KPL/FK Cassini Spacecraft Frame Definitions Kernel ============================================================================== This frame kernel contains the Cassini spacecraft, science instrument, and communication antennae frame definitions. Version and Date ---------------------------------------------------------- The TEXT_KERNEL_ID stores version information of loaded project text kernels. Each entry associated with the keyword is a string that consists of four parts: the kernel name, version, entry date, and type. For example, the ISS I-kernel might have an entry as follows: TEXT_KERNEL_ID += 'CASSINI_ISS V0.0.0 29-SEPTEMBER-1999 IK' | | | | | | | | KERNEL NAME <-------+ | | | | | V VERSION <-------+ | KERNEL TYPE | V ENTRY DATE Cassini Frame Kernel Version: \begindata TEXT_KERNEL_ID += 'CASSINI_FRAMES V3.7.0 20-NOVEMBER-2003 FK' \begintext Version 3.7 -- November 20, 2003 -- Lee Elson -- Updated CASSINI_XBAND per Diane Conner's request email. This was done by modifying the CASSINI_KABAND boresight vector. See [48] for details. Version 3.6 -- April 18, 2003 -- Lee Elson -- Modified CASSINI_XBAND frame definition so that its values are the same as CASSINI_KABAND. Added a new frame called CASSINI_XBAND_TRUE (NAIF ID -82108) that has the same definition parameters as the old CASSINI_XBAND. Also modified text structure so that changes are dated and stand out better for the human reader. See [46] and [47] for details. -- Modified descriptive text structure so that changes are dated and stand out better for the human reader. Version 3.5 -- September 4, 2002 -- Scott Turner, Richard West, and Rick McCloskey -- Entries for CASSINI_VIMS_IR_SOL, CASSINI_RADAR_2, and CASSINI_RADAR_4 were updated to reflect current values. See [42], [43], and [44] for details. -- CASSINI_VIMS_IR_SOL is now referenced directly to the spacecraft frame, CASSINI_SC_COORD, rather than CASSINI_VIMS_IR. Version 3.4 -- June 11, 2002 -- Scott Turner and Joshua Colwell -- Entries for CASSINI_KABAND were updated per Diane Conner's request email. See [38] for details. -- Updated entries for CASSINI_CIRS_FPB, CASSINI_CIRS_FP1, CASSINI_CIRS_FP3, and CASSINI_CIRS_FP4 based on updated alignment information provided in ECR 100515. See [39] for details. -- Modified the entries for CASSINI_UVIS_HSP, CASSINI_UVIS_FUV, and CASSINI_UVIS_EUV to match the body vector table provided by Alain Jouchoux in May 3, 2002 e-mail. This same data set is in the CASPER UVIS definition file. Verified that CASPER and PDT give consistent results using this frame kernel. -- Updated the entry for CASSINI_VIMS_IR to match the body vector table entry provided by Rick McCloskey. See [41] for details. Version 3.3 -- February 20, 2002 -- Scott Turner -- Updated the frame entry and documentation for CASSINI_VIMS_RAD as a result of ECR 101029 and documentation submitted with it. See [36] for details. Version 3.2 -- January 22, 2002 -- Scott Turner -- Updated frame entries for CASSINI_XBAND and CASSINI_KABAND as a result of SCR 490. See [35] for details. Version 3.1 -- August 9, 2001 -- Scott Turner -- Updated frame entries for CASSINI_XBAND and CASSINI_KABAND as a result of SCR 468. See [34] for details. Version 3.0 -- April 23, 2001 -- Scott Turner -- Restructured the articulating frames: CASSINI_MIMI_LEMMS1, CASSINI_MIMI_LEMMS2, CASSINI_CDA, CASSINI_CAPS. They now allow for multiple paths from the instrument frames to the spacecraft frame depending on what C-kernels are available. Use caution when loading conflicting C-kernels. -- Renamed CASSINI_SRU to CASSINI_SRU-A and added CASSINI_SRU-B, CASSINI_SRU-A_RAD, and CASSINI_SRU-B_RAD. -- Added the CASSINI_UVIS_SOLAR frame definition to support the UVIS solar occultation port FOV. -- Removed CASSINI_UVIS_EUV_OCC and CASSINI_UVIS_FUV_OCC frame definitions since the FOVs they support are actually tied to CASSINI_UVIS_EUV and CASSINI_UVIS_FUV frames respectively. -- Added the CASSINI_VIMS_IR_SOL frame definition to support the IR channel solar port FOV. Version 2.9 -- November 16, 2000 -- Scott Turner -- Corrected the definition of CASSINI_MIMI_INCA to account for the 9.5 degree offset from the spacecraft -Y axis. -- Corrected the definition of CASSINI_INMS. The Z-axis of this frame is now co-aligned with the -X axis of CASSINI_SC_COORD. Version 2.8 -- October 9, 2000 -- Scott Turner -- Updated CASSINI_ISS_NAC and CASSINI_ISS_WAC to reflect the updates associated with the Fomalhaut images taken on September 18, 2000. -- Migrated the CASSINI_ISS_NAC_RAD, CASSINI_ISS_WAC_RAD, CASSINI_VIMS_RAD, CASSINI_CIRS_RAD, CASSINI_CAPS, CASSINI_CDA, CASSINI_INMS, CASSINI_MAG_PLUS, CASSINI_MAG_MINUS, CASSINI_MIMI_CHEMS, CASSINI_MIMI_INCA, CASSINI_MIMI_LEMMS1, CASSINI_MIMI_LEMMS2, CASSINI_RADAR_1, CASSINI_RADAR_2, CASSINI_RADAR_3, CASSINI_RADAR_4, CASSINI_RADAR_5, CASSINI_RPWS, CASSINI_RPWS_EXPLUS, CASSINI_RPWS_EXMINUS, CASSINI_EZPLUS, CASSINI_RPWS_LP, CASSINI_KUBAND, and CASSINI_SBAND frames from the prototype section. -- Updated CASSINI_XBAND and CASSINI_KABAND as the result of SCR 367. These frames were migrated from the prototype section as well. Version 2.7 -- July 7, 2000 -- Scott Turner -- Added the following frame entries RPWS requested: CASSINI_RPWS_EXPLUS, CASSINI_RPWS_EXMINUS, CASSINI_RPWS_EZPLUS, CASSINI_RPWS_LP to the prototype frame section. See [14] for details. -- Changed the following frame names: CASSINI_HGA_X -> CASSINI_XBAND, CASSINI_HGA_S -> CASSINI_SBAND, CASSINI_HGA_KA -> CASSINI_KABAND, CASSINI_HGA_KU -> CASSINI_KUBAND. -- Halved the Euler angles associated with the CASSINI_CIRS_FP3 and CASSINI_FP4 frames. See [15] for details. Version 2.6 -- June 26, 2000 -- Scott Turner -- The RSS frame entries in the prototype section were renamed to HGA based frames. -- Removed the CASSINI_MAG frame and replaced it with the CASSINI_MAG_PLUS and CASSINI_MAG_MINUS frames. Version 2.5 -- April 2, 2000 -- Scott Turner -- Added CASSINI_VIMS. -- Added CASSINI_UVIS_FUV, CASSINI_UVIS_EUV, CASSINI_UVIS_FUV_OCC, CASSINI_UVIS_EUV_OCC, CASSINI_UVIS_HSP, and CASSINI_UVIS_HDAC. -- Fixed the keywords defining the CASSINI_HGA frame to use the proper ID code, -82101. -- Updated CASSINI_ISS_NAC and CASSINI_ISS_WAC to reflect the latest boresight information available in ECR's 100078 and 100079. Version 2.4 -- March 27, 2000 -- Scott Turner -- Added the CIRS Focal Plane Boresight frame, CASSINI_CIRS_FPB. -- CASSINI_CIRS_FP1, CASSINI_CIRS_FP3, CASSINI_CIRS_FP2 are no longer relative to CASSINI_SC_COORD but to the intermediate frame CASSINI_CIRS_FPB. -- Migrated the CASSINI_UVIS frame from the prototype section and added the CASSINI_UVIS_OCC frame. -- Added the TEXT_KERNEL_ID keyword to make version information accessible to programs at runtime. Version 2.3 -- March 9, 2000 -- Scott Turner -- Updated the Euler angles for CASSINI_CIRS_FP1, CASSINI_CIRS_FP3, and CASSINI_CIRS_FP4. Migrated them from the prototype section into the CIRS Section of the FK. Version 2.2 -- September 10, 1999 -- Scott Turner -- Removed TKFRAME_[ID]_BORESIGHT keyword for all but the antenna frames present. This information can now be found in the instrument kernel with the keyword: INS[ID]_BORESIGHT. -- Added a frame for the Stellar Reference Unit (SRU). -- Added prototype frame entries for several instruments. The transformations stored here for these frames are NOT for any real calculations, and in some cases are not connected with the actual instrument pointing at all. These frames will migrate from the prototype section as the kernel evolves. -- Changed CASSINI_SC_BUS to CASSINI_SC_COORD. -- Changed the LGA frame name definitions to CASSINI_LGA1 and CASSINI_LGA2 to accomodate simple translation to flight software frame names. -- Changed NAC and WAC ID codes from -82010 and -82020 to -82360 and -82361 respectively. This is to conform to the new ID code scheme proposed by Jeff Boyer. -- Altered the textual description of the spacecraft coordinate system to conform with [8]. -- Added some text from [8] to the ISS_NAC frame description. Version 2.1 -- July 14, 1999 -- Scott Turner -- Fixed incorrect comments regarding the NAC images. -- Fixed an improperly specified transformation for LGA2. -- Added TKFRAME_[ID]_BORESIGHT keyword for the frames present. Version 2.0 -- May 5, 1999 -- Scott Turner -- Added ISS NAC and WAC instrument frames. Version 1.0 -- May 14, 1998 -- Jeff Bytof -- Initial Release. References ---------------------------------------------------------- 1. ``C-kernel Required Reading'' 2. ``Kernel Pool Required Reading'' 3. ``Frames Required Reading'' 4. Cassini spacecraft blueprints. Provided by Kevin Tong, JPL. 5. ``Cassini Science Instruments and Investigations'', Revised Second Printing. Stephen J. Edberg. 6. ``Determination of the ISS Boresights in Cassini Spacecraft Coordinate System.'' Carolyn Porco and Vance Haemmerle. 7. Email from Vance Haemmerle regarding WAC alignment. 8. Cassini Document No. 699-406 ``Project Guidance Analysis Book'' 9. CASPER CIRS I-kernel Version 3.2 10. CIRS Fields-of-View PDF attached in an email from Stephen Edberg to Diane Conner. 11. Cassini Engineering Change Request #100078 12. Cassini Engineering Change Request #100079 13. CASPER VIMS I-kernel Version Version 4.2 14. Email from Terry Averkamp regarding new RPWS frame entries. 15. Email from Richard Achterberg regarding the CIRS frame entries. 16. Email from Vance Haemmerle regarding the Fomalhaut updates to the ISS NAC and WAC alignments. 17. Email from Jeff Boyer regarding radiator boresight alignments, MIMI_CHEMS orientation, and RPWS orientation. 18. Email from Sascha Kempf regarding CDA articulation. 19. CASPER INMS I-kernel Version 5.0 20. Email from Marcia Burton regarding the MAG field of views and frame definitions. 21. CASPER MAG I-kernel Version 6.0 22. CASPER MIMI I-kernel Version 4.0 23. CASPER RADAR I-kernel Version 2.2 24. Email from Terry Averkamp discussing the new RPWS frame entries. 25. Email from Thomas Burk regarding the updates to CASSINI_XBAND and CASSINI_KABAND frames that were the result of SCR 367. 26. Email from Deborah Bass regarding a correct in the CASSINI_INMS frame definition. 27. Email from Donald Mitchell regarding a correction in the CASSINI_MIMI_INCA frame definition. 28. Email from Rick McCloskey regarding updates and additions to the VIMS frame set. 29. Email from Joshua Colwell regarding the CASSINI_UVIS_SOLAR frame definition. 30. Email from Joshua Colwell verifying the CASSINI_UVIS_SOLAR frame definition. 31. Email from Rick McCloskey confirming the CASSINI_VIMS_V, CASSINI_VIMS_IR, CASSINI_VIMS_IR_SOL frame definitions. 32. Email from Jeff Boyer providing CASSINI_SRU_RAD frame definition. 33. Email from Don Mitchell describing the CASSINI_MIMI_LEMMS1 and CASSINI_MIMI_LEMMS2 articulation characteristics. 34. Email from Trina Ray describing updates for the CASSINI_XBAND and CASSINI_KABAND frame definitions. 35. Email from Diane Conner describing updates for the CASSINI_XBAND and CASSINI_KABAND boresights. 36. Cassini ECR 101029 - Change CASSINI_VIMS_RAD frame definition. 37. Cassini ECR 10325-B -- Change VIMS Sun Viewing Constraints Flight Rule FF37B2. 38. Email from Diane Conner regarding CASSINI_KABAND updated boresight information. 39. Page 28 from ECR 100515 listing updated alignment information for CASSINI_CIRS detectors. 40. Joshua Colwell's updated version 3.3.1 Cassini Spacecraft Frame Definition kernel. 41. Email from Rick McCloskey regarding the values in the body vector table for CASSINI_VIMS_IR. 42. Email from Rick McCloskey regarding the Euler angles for CASSINI_VIMS_IR_SOL, the VIMS solar port. 43. Email correction from Rick McCloskey regarding the Euler angles for CASSINI_VIMS_IR_SOL. 44. Email from Richard West regarding the CASSINI_RADAR_2 and CASSINI_RADAR_4 Euler angles. 45. Spreadsheet (gnumeric format) from Rick McCloskey regarding the Euler angles for CASSINI_VIMS_IR_SOL. 46. Email from Nicole Rappaport outlining needed changes to frame and radio science instrument kernel due to project use of Ka band data for X band pointing. 47. Cassini ECR number 102788 -- Additional Frame and FOV definitions to SPICE FK & IK Files for RSS 48. Cassini R/SCR NO: 613 -- Update the Onboard XBAND body vector table entries for GWE#3 Contact Information ---------------------------------------------------------- Direct questions, comments, or concerns about the contents of this kernel to: Lee Elson, NAIF/JPL, (818)-354-4223, Lee.Elson@jpl.nasa.gov Implementation Notes ---------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this frame kernel must `load' the kernel, normally during program initialization. Loading the kernel associates data items with their names in a data structure called the `kernel pool'. The SPICELIB routine LDPOOL loads a kernel file into the pool as shown below: CALL LDPOOL ( frame_kernel_name ) In order for a program or subroutine to extract data from the pool, the SPICELIB routines GDPOOL and GIPOOL are used. See [2] for more details. This file was created and may be updated with a text editor or word processor. Note: the keyword TKFRAME_[ID]_BORESIGHT defines the instrument or antenna boresight axis in the instrument or antenna frame. Cassini Frames ---------------------------------------------------------- The following Cassini frames are defined in this kernel file: Frame Name Relative To Type NAIF ID ======================= =================== ======= ======= AACS Body Frame: ---------------- CASSINI_SC_COORD J2000 CK -82000 CASSINI_SRU-A CASSINI_SC_COORD FIXED -82001 CASSINI_SRU-B CASSINI_SC_COORD FIXED -82002 CASSINI_SRU-A_RAD CASSINI_SC_COORD FIXED -82008 CASSINI_SRU-B_RAD CASSINI_SC_COORD FIXED -82009 Antenna Frames (-821xx): ------------------------ CASSINI_HGA CASSINI_SC_COORD FIXED -82101 CASSINI_LGA1 CASSINI_SC_COORD FIXED -82102 CASSINI_LGA2 CASSINI_SC_COORD FIXED -82103 CASSINI_XBAND CASSINI_SC_COORD FIXED -82104 CASSINI_KABAND CASSINI_SC_COORD FIXED -82105 CASSINI_KUBAND CASSINI_SC_COORD FIXED -82106 CASSINI_SBAND CASSINI_SC_COORD FIXED -82107 CASSINI_XBAND_TRUE CASSINI_SC_COORD FIXED -82108 ISS Frames (-8236x): ------------------------ CASSINI_ISS_NAC CASSINI_SC_COORD FIXED -82360 CASSINI_ISS_WAC CASSINI_SC_COORD FIXED -82361 CASSINI_ISS_NAC_RAD CASSINI_SC_COORD FIXED -82368 CASSINI_ISS_WAC_RAD CASSINI_SC_COORD FIXED -82369 CIRS Frames (-8289x): ------------------------ CASSINI_CIRS_FP1 CASSINI_CIRS_FPB FIXED -82890 CASSINI_CIRS_FP3 CASSINI_CIRS_FPB FIXED -82891 CASSINI_CIRS_FP4 CASSINI_CIRS_FPB FIXED -82892 CASSINI_CIRS_FPB CASSINI_SC_COORD FIXED -82893 CASSINI_CIRS_RAD CASSINI_SC_COORD FIXED -82898 UVIS Frames (-8284x): ------------------------ CASSINI_UVIS_FUV CASSINI_SC_COORD FIXED -82840 CASSINI_UVIS_EUV CASSINI_SC_COORD FIXED -82842 CASSINI_UVIS_SOLAR CASSINI_SC_COORD FIXED -82843 CASSINI_UVIS_HSP CASSINI_SC_COORD FIXED -82844 CASSINI_UVIS_HDAC CASSINI_SC_COORD FIXED -82845 VIMS Frames (-8283x): ------------------------ CASSINI_VIMS_V CASSINI_SC_COORD FIXED -82370 CASSINI_VIMS_IR CASSINI_SC_COORD FIXED -82371 CASSINI_VIMS_IR_SOL CASSINI_SC_COORD FIXED -82372 CASSINI_VIMS_RAD CASSINI_SC_COORD FIXED -82378 CAPS Frames (-8282x): ------------------------ CASSINI_CAPS_BASE CASSINI_SC_COORD FIXED -82822 CASSINI_CAPS_ART CASSINI_CAPS_BASE CK -82821 CASSINI_CAPS CASSINI_CAPS_ART CK -82820 CASSINI_SC_COORD CK -82820 CDA Frames (-8279x): ------------------------ CASSINI_CDA_BASE CASSINI_SC_COORD FIXED -82792 CASSINI_CDA_ART CASSINI_CDA_BASE CK -82971 CASSINI_CDA CASSINI_CDA_ART CK -82790 CASSINI_SC_COORD CK -82790 INMS Frames (-8274x): ------------------------ CASSINI_INMS CASSINI_SC_COORD FIXED -82740 MAG Frames (-8235x): ------------------------ CASSINI_MAG_PLUS CASSINI_SC_COORD FIXED -82350 CASSINI_MAG_MINUS CASSINI_SC_COORD FIXED -82351 MIMI Frames (-8276x): ------------------------ CASSINI_MIMI_CHEMS CASSINI_SC_COORD FIXED -82760 CASSINI_MIMI_INCA CASSINI_SC_COORD FIXED -82761 CASSINI_MIMI_LEMMS_BASE CASSINI_SC_COORD FIXED -82765 CASSINI_MIMI_LEMMS_ART CASSINI_MIMI_LEMMS_BASE CK -82764 CASSINI_MIMI_LEMMS1 CASSINI_MIMI_LEMMS_ART CK -82762 CASSINI_SC_COORD CK -82762 CASSINI_MIMI_LEMMS2 CASSINI_MIMI_LEMMS_ART CK -82763 CASSINI_SC_COORD CK -82763 RADAR Frames (-8281x): ------------------------ CASSINI_RADAR_1 CASSINI_SC_COORD FIXED -82810 CASSINI_RADAR_2 CASSINI_SC_COORD FIXED -82811 CASSINI_RADAR_3 CASSINI_SC_COORD FIXED -82812 CASSINI_RADAR_4 CASSINI_SC_COORD FIXED -82813 CASSINI_RADAR_5 CASSINI_SC_COORD FIXED -82814 RPWS Frames (-8273x): ------------------------ CASSINI_RPWS CASSINI_SC_COORD FIXED -82730 CASSINI_RPWS_EXPLUS CASSINI_SC_COORD FIXED -82731 CASSINI_RPWS_EXMINUS CASSINI_SC_COORD FIXED -82732 CASSINI_RPWS_EZPLUS CASSINI_SC_COORD FIXED -82733 CASSINI_RPWS_LP CASSINI_SC_COORD FIXED -82734 where: the frame ID codes are built from the spacecraft ID code, the instrument subsystem number, and the instrument number in a multiple instrument subsystem. The numbers 8 and 9 are reserved for the radiators. For example the ISS frame IDs are constructed as follows: CASSINI_ISS_WAC ID = -82 36 1 | | | | | | SPACECRAFT ID CODE <-----+ | +----> INSTRUMENT NUMBER | V INSTRUMENT SUBSYSTEM NUMBER Cassini Frames Hierarchy ---------------------------------------------------------- Notes: This diagram is subject to major revisions as this kernel evolves to suit the needs of each instrument. The articulating instrument frames have two paths back to the spacecraft frame. The first is a direct path via a single C-kernel connecting the instrument frame to the spacecraft frame. The second is one that utilizes a fixed offset C-kernel to rotate the instrument frame into the articulation frame, and then an articulation C-kernel and a base frame. For details see the sections for CASSINI_CDA, CASSINI_CAPS, and CASSINI_MIMI_LEMMS. The diagram below shows the Cassini frames hierarchy: 'IAU_EARTH' (EARTH BODY FIXED) | |<--- pck | 'J2000' INERTIAL | |<--- ck | 'CASSINI_SC_COORD' | 'CASSINI_SRU-A' | 'CASSINI_SRU-B' | 'CASSINI_SRU-A_RAD' | 'CASSINI_SRU-B_RAD' | 'CASSINI_HGA' | 'CASSINI_XBAND' | 'CASSINI_KABAND' | | | 'CASSINI_XBAND_TRUE' | 'CASSINI_KUBAND' | 'CASSINI_SBAND' | 'CASSINI_LGA1' | 'CASSINI_LGA2' | 'CASSINI_ISS_NAC' | 'CASSINI_ISS_WAC' | 'CASSINI_ISS_NAC_RAD' | 'CASSINI_ISS_WAC_RAD' | 'CASSINI_CIRS_FPB' | | | 'CASSINI_CIRS_FP1' | | | 'CASSINI_CIRS_FP3' | | | 'CASSINI_CIRS_FP4' | 'CASSINI_CIRS_RAD' | 'CASSINI_UVIS_FUV' | 'CASSINI_UVIS_EUV' | 'CASSINI_UVIS_SOLAR' | 'CASSINI_UVIS_HSP' | 'CASSINI_UVIS_HDAC' | 'CASSINI_VIMS_V' | 'CASSINI_VIMS_IR' | 'CASSINI_VIMS_IR_SOL' | 'CASSINI_VIMS_RAD' | 'CASSINI_CAPS_BASE' | | | |<--- ck | | | 'CASSINI_CAPS_ART' | | | |<--- ck | | o------'CASSINI_CAPS' | ^ | | | + ck | 'CASSINI_CDA_BASE' | | | |<--- ck | | | 'CASSINI_CDA_ART' | | | |<--- ck | | o------'CASSINI_CDA' | ^ | | | + ck | 'CASSINI_INMS' | 'CASSINI_MAG_PLUS' | 'CASSINI_MAG_MINUS' | 'CASSINI_MIMI_CHEMS' | 'CASSINI_MIMI_INCA' | 'CASSINI_MIMI_LEMMS_BASE' | | | |<--- ck | | | 'CASSINI_MIMI_LEMMS_ART' | | | |<--- ck | | o------'CASSINI_MIMI_LEMMS1' | ^ | | | | | + ck | | | o------'CASSINI_MIMI_LEMMS2' | ^ | | | + ck | 'CASSINI_RADAR_1' | 'CASSINI_RADAR_2' | 'CASSINI_RADAR_3' | 'CASSINI_RADAR_4' | 'CASSINI_RADAR_5' | 'CASSINI_RPWS' | 'CASSINI_RPWS_EXPLUS' | 'CASSINI_RPWS_EXMINUS' | 'CASSINI_RPWS_EZPLUS' | 'CASSINI_RPWS_LP' Spacecraft Frame ---------------------------------------------------------- From [8]: (Note: The figures referenced below can not be reproduced here. There is a diagram below that basically illustrates what is contained there.) ``The Stellar reference Unit (SRU) detector is a CCD. Its coordinate system is defined according to the geometry of the detector. Figure 2.1.2a depicts the SRU orientation and coordinates relative to the S/C coordinates. From the ACS point of view, the S/C coordinate system is defined with respect to the SRU coordinate frame, such that : +X = +b (SRU boresight) +Y = +v +Z = -h Therefore, by definition, there are no misalignments between the SRU and the S/C coordinate frames. The SRU coordinate system is defined by the pixel and line shift directions defined in Figure 2.1.2b. These directions are represented by unit vectors h and v respectively. Both h and v pass through the origin which is located at the exact center of the 1024 x 1024 array. As indicated in Figure 2.1.2b, the SRU boresight b passes through this point, is normal to both h and v, and points outward through the optics towards the scene being viewed.'' Stellar Reference Unit Frame: Cassini Spacecraft /\ ---------------------------------- \ / \ / HGA \ / MAG Boom -------------------------- ... =================| | | h | \ ^ / | | | | | | Y <-------| v <---o | sc | b, X | | sc | | | | | | | | | ---------------------- / \ / \ Main Rocket Engine ---------- | | | V Z sc where b and X point out of the screen or page. sc From [8]: ``The spacecraft basebody coordinate system is a body fixed coordinate system. It is a structural coordinate system defined when the spacecraft is assembled. The primary geometrical and mass properties are fixed to this system. The (X,Y,Z) coordinate system is not observable in space. Referring to Figure 2.1.1, the origin of the spacecraft coordinate system lies at the center of the field joint between the bus and the upper equipment module (UEM) upper shell structure assembly [7]. This location is defined by bolt holes A, D, and H (as shown on the Configuration lay out 10129891, Figure 3). The Z-axis emanates from the origin and is perpendicular to a plane generated by the mating surfaces of the bus at bolt holes A, D, and H. The +Z-axis is on the propulsion module side of the interface. The X-axis emanates from the origin and is parallel to the line through the true centers of bolt holes A and H at the bus and the UEM upper shell structure assembly interface. The -X-axis points towards the Huygens probe. The Y-axis is mutually perpendicular to the X and Z axes, with the +Y axis oriented along the magnetometer boom.'' Spacecraft bus attitude with respect to an inertial frame is provided by a C kernel (see [1] for more information). \begindata FRAME_CASSINI_SC_COORD = -82000 FRAME_-82000_NAME = 'CASSINI_SC_COORD' FRAME_-82000_CLASS = 3 FRAME_-82000_CLASS_ID = -82000 FRAME_-82000_CENTER = -82 CK_-82000_SCLK = -82 CK_-82000_SPK = -82 \begintext The nominal definition of the Stellar Reference Unit-A frame is displayed below. As described above and in [8], the boresight axis lies along the spacecraft +X axis. The rotation matrix that takes vectors from the SRU-A frame into the spacecraft frame is computed: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_SRU-A = -82001 FRAME_-82001_NAME = 'CASSINI_SRU-A' FRAME_-82001_CLASS = 4 FRAME_-82001_CLASS_ID = -82001 FRAME_-82001_CENTER = -82 TKFRAME_-82001_SPEC = 'ANGLES' TKFRAME_-82001_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82001_ANGLES = ( 0.0, -90.0, 0.0 ) TKFRAME_-82001_AXES = ( 3, 2, 1 ) TKFRAME_-82001_UNITS = 'DEGREES' \begintext The nominal definition of the Stellar Reference Unit-B frame is displayed below. Nominally SRU-A and SRU-B are aligned, so the boresight axis lies along the spacecraft +X axis. The rotation matrix that takes vectors from the SRU-B frame into the spacecraft frame is computed: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_SRU-B = -82002 FRAME_-82002_NAME = 'CASSINI_SRU-B' FRAME_-82002_CLASS = 4 FRAME_-82002_CLASS_ID = -82002 FRAME_-82002_CENTER = -82 TKFRAME_-82002_SPEC = 'ANGLES' TKFRAME_-82002_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82002_ANGLES = ( 0.0, -90.0, 0.0 ) TKFRAME_-82002_AXES = ( 3, 2, 1 ) TKFRAME_-82002_UNITS = 'DEGREES' \begintext The nominal definition of the Stellar Reference Unit-A Radiator frame is displayed below. As described in [32], the rotation matrix that takes vectors from the SRU-A_RAD frame into the spacecraft frame is computed: [ ] [ ] [ ] [ ] [ ROT ] = [ 180.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_SRU-A_RAD = -82008 FRAME_-82008_NAME = 'CASSINI_SRU-A_RAD' FRAME_-82008_CLASS = 4 FRAME_-82008_CLASS_ID = -82008 FRAME_-82008_CENTER = -82 TKFRAME_-82008_SPEC = 'ANGLES' TKFRAME_-82008_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82008_ANGLES = ( 180.0, -90.0, 0.0 ) TKFRAME_-82008_AXES = ( 3, 1, 3 ) TKFRAME_-82008_UNITS = 'DEGREES' \begintext The nominal definition of the Stellar Reference Unit-B Radiator frame is displayed below. As with the SRU-B frame, this is nominally the same frame as SRU-A_RAD. The rotation matrix that takes vectors from the SRU-B_RAD frame into the spacecraft frame is computed: [ ] [ ] [ ] [ ] [ ROT ] = [ 180.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_SRU-B_RAD = -82009 FRAME_-82009_NAME = 'CASSINI_SRU-B_RAD' FRAME_-82009_CLASS = 4 FRAME_-82009_CLASS_ID = -82009 FRAME_-82009_CENTER = -82 TKFRAME_-82009_SPEC = 'ANGLES' TKFRAME_-82009_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82009_ANGLES = ( 180.0, -90.0, 0.0 ) TKFRAME_-82009_AXES = ( 3, 1, 3 ) TKFRAME_-82009_UNITS = 'DEGREES' \begintext Antenna Frame Definitions ---------------------------------------------------------- This section of the frames kernel defines the Cassini spacecraft antenna frames. The ID codes associated with each of the frames are determined by subtracting the three digit antenna code (101-103) from the DSN Cassini spacecraft bus ID code (-82000). Note the angles in the frame definitions are specified for the "from antenna to (relative to) base frame" transformation. High Gain Antenna (HGA) The high gain antenna points nominally along the spacecraft -Z axis. As such the rotation matrix required that takes vectors represented in the high gain antenna frame into the spacecraft frame is constructed as follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ +180.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_HGA = -82101 FRAME_-82101_NAME = 'CASSINI_HGA' FRAME_-82101_CLASS = 4 FRAME_-82101_CLASS_ID = -82101 FRAME_-82101_CENTER = -82 TKFRAME_-82101_SPEC = 'ANGLES' TKFRAME_-82101_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82101_ANGLES = ( 0.0, 180.0, 0.0 ) TKFRAME_-82101_AXES = ( 3, 2, 1 ) TKFRAME_-82101_UNITS = 'DEGREES' TKFRAME_-82101_BORESIGHT = ( 0.0, 0.0, 1.0 ) \begintext The XBAND, XBAND_TRUE, KABAND, KUBAND, and SBAND frames are all frames associated with the orbiter's High Gain Antenna. These names were chosen for reasons of consistency with AACS, PDT, and sequencing software. High Gain Antenna X Band (XBAND) The high gain antenna is capable of operating in several bands, each of which may be calibrated and adjusted independently. The nominal frame definition for the XBAND is displayed below: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ 180.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: FRAME_CASSINI_XBAND = -82104 FRAME_-82104_NAME = 'CASSINI_XBAND' FRAME_-82104_CLASS = 4 FRAME_-82104_CLASS_ID = -82104 FRAME_-82104_CENTER = -82 TKFRAME_-82104_SPEC = 'ANGLES' TKFRAME_-82104_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82104_ANGLES = ( 0.0, 0.0, 180.0 ) TKFRAME_-82104_AXES = ( 3, 2, 1 ) TKFRAME_-82104_UNITS = 'DEGREES' From [25], the XBAND boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0005000 ] XBAND Boresight Vector = [ 0.0004000 ] [ -0.9999998 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -128.659808 ] [ -179.963313 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. First Updated Frame Definition: FRAME_CASSINI_XBAND = -82104 FRAME_-82104_NAME = 'CASSINI_XBAND' FRAME_-82104_CLASS = 4 FRAME_-82104_CLASS_ID = -82104 FRAME_-82104_CENTER = -82 TKFRAME_-82104_SPEC = 'ANGLES' TKFRAME_-82104_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82104_ANGLES = ( -128.659808, -179.963313, 0.0 ) TKFRAME_-82104_AXES = ( 3, 1, 3 ) TKFRAME_-82104_UNITS = 'DEGREES' From [34], the XBAND boresight has been adjusted again to the following vector in spacecraft coordinates: [ 0.0005200 ] XBAND Boresight Vector = [ 0.0005800 ] [ -0.9999997 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -138.12213046232 ] [ -179.95536809121 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. Second Updated Frame Definition: FRAME_CASSINI_XBAND = -82104 FRAME_-82104_NAME = 'CASSINI_XBAND' FRAME_-82104_CLASS = 4 FRAME_-82104_CLASS_ID = -82104 FRAME_-82104_CENTER = -82 TKFRAME_-82104_SPEC = 'ANGLES' TKFRAME_-82104_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82104_ANGLES = ( -138.12213046232, -179.95536809121, 0.0 ) TKFRAME_-82104_AXES = ( 3, 1, 3 ) TKFRAME_-82104_UNITS = 'DEGREES' From [35], the XBAND boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0004839 ] XBAND Boresight Vector = [ 0.0001745 ] [ -0.9999999 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -109.82989689352 ] [ -179.97052693372 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. Third Updated Frame Definition: FRAME_CASSINI_XBAND = -82104 FRAME_-82104_NAME = 'CASSINI_XBAND' FRAME_-82104_CLASS = 4 FRAME_-82104_CLASS_ID = -82104 FRAME_-82104_CENTER = -82 TKFRAME_-82104_SPEC = 'ANGLES' TKFRAME_-82104_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82104_ANGLES = ( -109.82989689352, -179.97052693372, 0.0 ) TKFRAME_-82104_AXES = ( 3, 1, 3 ) TKFRAME_-82104_UNITS = 'DEGREES' ______________________________________________________________ ++++++++++++++++++++March 18, 2003++++++++++++++++++++++++++++ From [46], the XBAND boresight has been adjusted so that it is co-aligned with the KABAND boresight. By defining the frame relative to 'CASSINI_KABAND', the following frame definition is valid: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Y where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_XBAND = -82104 FRAME_-82104_NAME = 'CASSINI_XBAND' FRAME_-82104_CLASS = 4 FRAME_-82104_CLASS_ID = -82104 FRAME_-82104_CENTER = -82 TKFRAME_-82104_SPEC = 'ANGLES' TKFRAME_-82104_RELATIVE = 'CASSINI_KABAND' TKFRAME_-82104_ANGLES = ( 0.0, 0.0, 0.0 ) TKFRAME_-82104_AXES = ( 3, 1, 2 ) TKFRAME_-82104_UNITS = 'DEGREES' \begintext High Gain Antenna X Band True (XBAND_TRUE) ______________________________________________________________ ++++++++++++++++++++March 18, 2003++++++++++++++++++++++++++++ In order to preserve the original boresight information for the XBAND antenna, a new frame is defined containing that information. The change history is documented above under the XBAND frame. From [35], the XBAND boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0004839 ] XBAND Boresight Vector = [ 0.0001745 ] [ -0.9999999 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -109.82989689352 ] [ -179.97052693372 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_XBAND_TRUE = -82108 FRAME_-82108_NAME = 'CASSINI_XBAND_TRUE' FRAME_-82108_CLASS = 4 FRAME_-82108_CLASS_ID = -82108 FRAME_-82108_CENTER = -82 TKFRAME_-82108_SPEC = 'ANGLES' TKFRAME_-82108_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82108_ANGLES = ( -109.82989689352, -179.97052693372, 0.0 ) TKFRAME_-82108_AXES = ( 3, 1, 3 ) TKFRAME_-82108_UNITS = 'DEGREES' \begintext High Gain Antenna KA Band (KABAND) The high gain antenna is capable of operating in several bands, each of which may be calibrated and adjusted independently. The nominal frame definition for the KABAND is displayed below: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ 180.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: FRAME_CASSINI_KABAND = -82105 FRAME_-82105_NAME = 'CASSINI_KABAND' FRAME_-82105_CLASS = 4 FRAME_-82105_CLASS_ID = -82105 FRAME_-82105_CENTER = -82 TKFRAME_-82105_SPEC = 'ANGLES' TKFRAME_-82105_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82105_ANGLES = ( 0.0, 0.0, 180.0 ) TKFRAME_-82105_AXES = ( 3, 2, 1 ) TKFRAME_-82105_UNITS = 'DEGREES' From [25], the KABAND boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0005000 ] KABAND Boresight Vector = [ 0.0004000 ] [ -0.9999998 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -128.659808 ] [ -179.963313 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. First Updated Frame Definition: FRAME_CASSINI_KABAND = -82105 FRAME_-82105_NAME = 'CASSINI_KABAND' FRAME_-82105_CLASS = 4 FRAME_-82105_CLASS_ID = -82105 FRAME_-82105_CENTER = -82 TKFRAME_-82105_SPEC = 'ANGLES' TKFRAME_-82105_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82105_ANGLES = ( -128.659808, -179.963313, 0.0 ) TKFRAME_-82105_AXES = ( 3, 1, 3 ) TKFRAME_-82105_UNITS = 'DEGREES' From [34], the KABAND boresight has been adjusted again to the following vector in spacecraft coordinates: [ 0.0005300 ] KABAND Boresight Vector = [ 0.0006600 ] [ -0.9999996 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -141.23448009520 ] [ -179.95150122158 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. Second Updated Frame Definition: FRAME_CASSINI_KABAND = -82105 FRAME_-82105_NAME = 'CASSINI_KABAND' FRAME_-82105_CLASS = 4 FRAME_-82105_CLASS_ID = -82105 FRAME_-82105_CENTER = -82 TKFRAME_-82105_SPEC = 'ANGLES' TKFRAME_-82105_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82105_ANGLES = ( -141.23448009520, -179.95150122158, 0.0 ) TKFRAME_-82105_AXES = ( 3, 1, 3 ) TKFRAME_-82105_UNITS = 'DEGREES' From [35], the KABAND boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0004839 ] KABAND Boresight Vector = [ 0.0001745 ] [ -0.9999999 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -109.82989689352 ] [ -179.97052693372 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. FRAME_CASSINI_KABAND = -82105 FRAME_-82105_NAME = 'CASSINI_KABAND' FRAME_-82105_CLASS = 4 FRAME_-82105_CLASS_ID = -82105 FRAME_-82105_CENTER = -82 TKFRAME_-82105_SPEC = 'ANGLES' TKFRAME_-82105_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82105_ANGLES = ( -109.82989689352, -179.97052693372, 0.0 ) TKFRAME_-82105_AXES = ( 3, 1, 3 ) TKFRAME_-82105_UNITS = 'DEGREES' From [38], the KABAND boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0005280 ] KABAND Boresight Vector = [ 0.0003500 ] [ -0.9999998 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -123.53955356526 ] [ -179.96370485104 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. FRAME_CASSINI_KABAND = -82105 FRAME_-82105_NAME = 'CASSINI_KABAND' FRAME_-82105_CLASS = 4 FRAME_-82105_CLASS_ID = -82105 FRAME_-82105_CENTER = -82 TKFRAME_-82105_SPEC = 'ANGLES' TKFRAME_-82105_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82105_ANGLES = ( -123.53955356526, -179.96370485104, 0.0 ) TKFRAME_-82105_AXES = ( 3, 1, 3 ) TKFRAME_-82105_UNITS = 'DEGREES' ______________________________________________________________ ++++++++++++++++++++November 20, 2003++++++++++++++++++++++++++++ From [48], the KABAND boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0004273 ] KABAND Boresight Vector = [ 0.0008606 ] [ -0.9999995 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -153.59495523828 ] [ -179.94494778906 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_KABAND = -82105 FRAME_-82105_NAME = 'CASSINI_KABAND' FRAME_-82105_CLASS = 4 FRAME_-82105_CLASS_ID = -82105 FRAME_-82105_CENTER = -82 TKFRAME_-82105_SPEC = 'ANGLES' TKFRAME_-82105_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82105_ANGLES = ( -153.59495523828, -179.94494778906, 0.0 ) TKFRAME_-82105_AXES = ( 3, 1, 3 ) TKFRAME_-82105_UNITS = 'DEGREES' \begintext High Gain Antenna KU Band (KUBAND) The high gain antenna is capable of operating in several bands, each of which may be calibrated and adjusted independently. The nominal frame definition for the KUBAND is displayed below: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ 180.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_KUBAND = -82106 FRAME_-82106_NAME = 'CASSINI_KUBAND' FRAME_-82106_CLASS = 4 FRAME_-82106_CLASS_ID = -82106 FRAME_-82106_CENTER = -82 TKFRAME_-82106_SPEC = 'ANGLES' TKFRAME_-82106_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82106_ANGLES = ( 0.0, 0.0, 180.0 ) TKFRAME_-82106_AXES = ( 3, 2, 1 ) TKFRAME_-82106_UNITS = 'DEGREES' \begintext High Gain Antenna S Band (SBAND) The high gain antenna is capable of operating in several bands, each of which may be calibrated and adjusted independently. The nominal frame definition for the SBAND is displayed below: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ 180.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_SBAND = -82107 FRAME_-82107_NAME = 'CASSINI_SBAND' FRAME_-82107_CLASS = 4 FRAME_-82107_CLASS_ID = -82107 FRAME_-82107_CENTER = -82 TKFRAME_-82107_SPEC = 'ANGLES' TKFRAME_-82107_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82107_ANGLES = ( 0.0, 0.0, 180.0 ) TKFRAME_-82107_AXES = ( 3, 2, 1 ) TKFRAME_-82107_UNITS = 'DEGREES' \begintext Low Gain Antenna One (LGA1) The first low gain antenna points nominally along the spacecraft -Z axis. As such the rotation matrix required that takes vectors represented in the first low gain antenna frame into the spacecraft frame is constructed as follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ +180.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_LGA1 = -82102 FRAME_-82102_NAME = 'CASSINI_LGA1' FRAME_-82102_CLASS = 4 FRAME_-82102_CLASS_ID = -82102 FRAME_-82102_CENTER = -82 TKFRAME_-82102_SPEC = 'ANGLES' TKFRAME_-82102_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82102_ANGLES = ( 0.0, 180.0, 0.0 ) TKFRAME_-82102_AXES = ( 3, 2, 1 ) TKFRAME_-82102_UNITS = 'DEGREES' TKFRAME_-82102_BORESIGHT = ( 0.0, 0.0, 1.0 ) \begintext Low Gain Antenna Two (LGA2) The second low gain antenna points nominally along the spacecraft -X axis. As such the rotation matrix required that takes vectors represented in the second low gain antenna frame into the spacecraft frame is constructed as follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_LGA2 = -82103 FRAME_-82103_NAME = 'CASSINI_LGA2' FRAME_-82103_CLASS = 4 FRAME_-82103_CLASS_ID = -82103 FRAME_-82103_CENTER = -82 TKFRAME_-82103_SPEC = 'ANGLES' TKFRAME_-82103_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82103_ANGLES = ( 0.0, 90.0, 0.0 ) TKFRAME_-82103_AXES = ( 3, 2, 1 ) TKFRAME_-82103_UNITS = 'DEGREES' TKFRAME_-82103_BORESIGHT = ( 0.0, 0.0, 1.0 ) \begintext ISS Frames ---------------------------------------------------------- The Narrow Angle Camera (NAC) and Wide Angle Camera (WAC) are mounted on the remote sensing pallet on the +X side of the Cassini spacecraft, and nominally directed along the -Y axis of the AACS body frame. Note the angles in the frame definitions are specified for the "from instrument to (relative to) base frame" transformation. Imaging Science Subsystem Narrow Angle Camera (ISS_NAC) The ISS NAC points nominally along the spacecraft -Y axis. The following frame definition encapsulates this nominal frame. From [8]: ``The Narrow Angle Camera (NAC) detector is a CCD. Its coordinate system is defined according to the geometry of the detector. The narrow angle coordinate system is defined in the same manner as the SRU coordinate systems defined above and the four central pixels of center of the full CCD are selected for the definition of the origin of the coordinate system. The Narrow Angle Camera is the primary instrument on the Remote Sensing Pallet (RSP). AACS is responsible for providing pointing knowledge of the boresight vector of this instrument. All other RSP instruments use the pointing provided to the NAC as their reference for determining their pointing.'' Nominal Frame Definition: FRAME_CASSINI_ISS_NAC = -82360 FRAME_-82360_NAME = 'CASSINI_ISS_NAC' FRAME_-82360_CLASS = 4 FRAME_-82360_CLASS_ID = -82360 FRAME_-82360_CENTER = -82 TKFRAME_-82360_SPEC = 'ANGLES' TKFRAME_-82360_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82360_ANGLES = ( -90.0, 0.0, 90.0 ) TKFRAME_-82360_AXES = ( 1, 2, 3 ) TKFRAME_-82360_UNITS = 'DEGREES' [6] describes the inflight calibration of the ISS that was the result of the CICLOPS (Cassini Imaging Central Laboratory for Operations) analysis of 8 NAC images that were taken during ICO (Instrument Checkout). The rotation matrix that takes vectors represented in the ISS_NAC frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ -90.024236 ] [ -0.047029483 ] [ 89.892082 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. The angles were taken directly from [6]. FRAME_CASSINI_ISS_NAC = -82360 FRAME_-82360_NAME = 'CASSINI_ISS_NAC' FRAME_-82360_CLASS = 4 FRAME_-82360_CLASS_ID = -82360 FRAME_-82360_CENTER = -82 TKFRAME_-82360_SPEC = 'ANGLES' TKFRAME_-82360_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82360_ANGLES = ( -90.024236, -0.047029483, 89.892082 ) TKFRAME_-82360_AXES = ( 1, 2, 3 ) TKFRAME_-82360_UNITS = 'DEGREES' From [10]: ``The NAC boresight is not precisely aligned with the S/C -Y body vector. Its alignment was determined during ICO-1 ISS observations of Spica, when the spacecraft was using SRU-B for orientation determination. The alignment parameters cited under Change Requested take into account the offset, as determined by AACS, between SRU-A and SRU-B.'' [10] also describes a series of frame transformations that convert the CASSINI_ISS_NAC frame into the CASSINI_SC_COORD frame, accounting for the offset between SRU-A and SRU-B. This results in following frame definition: The rotation matrix that takes vectors represented in the ISS_NAC frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ -89.99231636 ] [ -0.03586589 ] [ 89.93339682 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. FRAME_CASSINI_ISS_NAC = -82360 FRAME_-82360_NAME = 'CASSINI_ISS_NAC' FRAME_-82360_CLASS = 4 FRAME_-82360_CLASS_ID = -82360 FRAME_-82360_CENTER = -82 TKFRAME_-82360_SPEC = 'ANGLES' TKFRAME_-82360_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82360_ANGLES = (-89.99231636, -0.03586589, 89.93339682) TKFRAME_-82360_AXES = ( 1, 2, 3 ) TKFRAME_-82360_UNITS = 'DEGREES' From [16]: ``The following results were obtained by using 3 long exposure Fomalhaut NAC frames, each with 6 stars and using a 3 parameter fit (shift in line, shift in sample and rotation about optic axis).'' AACS NAC boresight X 0.0005760 +/- 0.0000018 Y -0.99999982 +/- 0.00000001 Z -0.0001710 +/- 0.0000016 The results of the Fomalhaut image calibrations produced the following update to the ISS_NAC frame defintion: The rotation matrix that takes vectors represented in the ISS_NAC frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ -90.009796 ] [ -0.03300 ] [ 89.9148 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_ISS_NAC = -82360 FRAME_-82360_NAME = 'CASSINI_ISS_NAC' FRAME_-82360_CLASS = 4 FRAME_-82360_CLASS_ID = -82360 FRAME_-82360_CENTER = -82 TKFRAME_-82360_SPEC = 'ANGLES' TKFRAME_-82360_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82360_ANGLES = (-90.009796, -0.03300, 89.9148 ) TKFRAME_-82360_AXES = ( 1, 2, 3 ) TKFRAME_-82360_UNITS = 'DEGREES' \begintext Imaging Science Subsystem Wide Angle Camera (ISS_WAC) The ISS WAC points nominally along the spacecraft -Y axis. The following frame definition encapsulates this nominal frame. Nominal Frame Definition: FRAME_CASSINI_ISS_WAC = -82361 FRAME_-82361_NAME = 'CASSINI_ISS_WAC' FRAME_-82361_CLASS = 4 FRAME_-82361_CLASS_ID = -82361 FRAME_-82361_CENTER = -82 TKFRAME_-82361_SPEC = 'ANGLES' TKFRAME_-82361_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82361_ANGLES = ( -90.0, 0.0, 90.0 ) TKFRAME_-82361_AXES = ( 1, 2, 3 ) TKFRAME_-82361_UNITS = 'DEGREES' [6] describes the inflight calibration of ISS that was the result of the CICLOPS (Cassini Imaging Central Laboratory for Operations) analysis of 36 WAC images taken during ICO (Instrument Checkout). At this time the images taken were only sufficient to develop the location of the WAC's optical axis. There are three determinations of this axes location in the spacecraft frame. In [7] V.Haemmerle suggests that the 2-parameter fit average coupled with nominal twist would be the safest assumption to determine the frame transformation from ISS_WAC to the AACS body frame. The rotation matrix that takes ISS_WAC vectors into the spacecraft frame would be constructed as follows: [ ] [ ] [ ] [ ] [ ROT ] = [ +89.9116120 ] [ -90.00059931 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y Z where [x] represents the rotation matrix of a given angle x about i axis i. These angles were computed using the assumption that the WAC optical axis lies along the vector: [ 0.00154266 ] WAC Optical Axis Vector = [ -0.99999881 ] [ -0.00001046 ] in AACS body coordinates. Further we assume nominal twist, hence the first rotation about Z is 0.0 degrees. FRAME_CASSINI_ISS_WAC = -82361 FRAME_-82361_NAME = 'CASSINI_ISS_WAC' FRAME_-82361_CLASS = 4 FRAME_-82361_CLASS_ID = -82361 FRAME_-82361_CENTER = -82 TKFRAME_-82361_SPEC = 'ANGLES' TKFRAME_-82361_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82361_ANGLES = ( 89.9116120, -90.00059931, 0.0 ) TKFRAME_-82361_AXES = ( 3, 2, 3 ) TKFRAME_-82361_UNITS = 'DEGREES' From [11]: ``The WAC boresight is not precisely aligned with the S/C -Y body vector. Its alignment was determined during ICO-1 ISS observations of Spica, when the spacecraft was using SRU-B for orientation determination. The alignment parameters cited under Change Request take into account the offset, as determined by AACS, between SRU-A and SRU-B.'' Taking the boresight from the ECR ([11]): [ 0.0013481161 ] WAC Optical Axis Vector = [ -0.99999894 ] [ 0.00054612156 ] and assuming no twist, we derive the following angles: [ ] [ ] [ ] [ ] [ ROT ] = [ +89.9227586 ] [ -89.96870954 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y Z where [x] represents the rotation matrix of a given angle x about i axis i. These angles were computed using the assumption that the WAC optical axis lies along the vector listed above. Further we assume nominal twist, hence the first rotation about Z is 0.0 degrees. FRAME_CASSINI_ISS_WAC = -82361 FRAME_-82361_NAME = 'CASSINI_ISS_WAC' FRAME_-82361_CLASS = 4 FRAME_-82361_CLASS_ID = -82361 FRAME_-82361_CENTER = -82 TKFRAME_-82361_SPEC = 'ANGLES' TKFRAME_-82361_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82361_ANGLES = ( 89.9227586, -89.96870954, 0.0 ) TKFRAME_-82361_AXES = ( 3, 2, 3 ) TKFRAME_-82361_UNITS = 'DEGREES' From [16]: ``The following results were obtained by using 3 long exposure Fomalhaut WAC frames, each using 12 stars near the center of frame and using a 3 parameter fit (shift in line, shift in sample and rotation about optic axis).'' AACS WAC boresight X 0.00121834 +/- 0.00000078 Y -0.99999923 +/- 0.00000001 Z 0.00025445 +/- 0.00000094 The results of the Fomalhaut image calibrations produced the following update to the ISS_WAC frame defintion: The rotation matrix that takes vectors represented in the ISS_NAC frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ -89.985421 ] [ -0.069806 ] [ 89.9736 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_ISS_WAC = -82361 FRAME_-82361_NAME = 'CASSINI_ISS_WAC' FRAME_-82361_CLASS = 4 FRAME_-82361_CLASS_ID = -82361 FRAME_-82361_CENTER = -82 TKFRAME_-82361_SPEC = 'ANGLES' TKFRAME_-82361_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82361_ANGLES = ( -89.985421, -0.069806, 89.9736 ) TKFRAME_-82361_AXES = ( 1, 2, 3 ) TKFRAME_-82361_UNITS = 'DEGREES' \begintext ISS Radiators (ISS_NAC_RAD and ISS_WAC_RAD) The ISS radiators are nominally oriented with their +Z axes directed down the spacecraft +X axis. Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. As [17] indicates, both the ISS_NAC_RAD and ISS_WAC_RAD boresights are nominally aligned with the +X axis in the spacecraft frame. By the methodology outlined above, this produces the following frame definitions: [ ] [ ] [ ] [ ] [ ROT ] = [ -90.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_ISS_NAC_RAD = -82368 FRAME_-82368_NAME = 'CASSINI_ISS_NAC_RAD' FRAME_-82368_CLASS = 4 FRAME_-82368_CLASS_ID = -82368 FRAME_-82368_CENTER = -82 TKFRAME_-82368_SPEC = 'ANGLES' TKFRAME_-82368_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82368_ANGLES = ( -90.0, -90.0, 0.0 ) TKFRAME_-82368_AXES = ( 3, 1, 3 ) TKFRAME_-82368_UNITS = 'DEGREES' \begintext Since the boresights are the same, both frame definitions are also the same, thus we have: Nominal Frame Definition: \begindata FRAME_CASSINI_ISS_WAC_RAD = -82369 FRAME_-82369_NAME = 'CASSINI_ISS_WAC_RAD' FRAME_-82369_CLASS = 4 FRAME_-82369_CLASS_ID = -82369 FRAME_-82369_CENTER = -82 TKFRAME_-82369_SPEC = 'ANGLES' TKFRAME_-82369_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82369_ANGLES = ( -90.0, -90.0, 0.0 ) TKFRAME_-82369_AXES = ( 3, 1, 3 ) TKFRAME_-82369_UNITS = 'DEGREES' \begintext CIRS Frames ---------------------------------------------------------- The Composite Infrared Spectrometer (CIRS) is mounted on the remote sensing pallet on the +X side of the Cassini spacecraft, and nominally directed along the -Y axis of the AACS body frame. Note the angles in the frame definitions are specified for the "from instrument to (relative to) base frame" transformation. Composite Infrared Spectrometer Focal Plane Boresight (CIRS_FPB) The CIRS FPB points nominally along the spacecraft -Y axis. The rotation matrix that takes vectors represented in the CIRS_FPB frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [-90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Y where [x] represents the rotation matrix of a given angle x about i axis i. The following frame definition encapsulates this nominal frame: Nominal Frame Definition FRAME_CASSINI_CIRS_FPB = -82893 FRAME_-82893_NAME = 'CASSINI_CIRS_FPB' FRAME_-82893_CLASS = 4 FRAME_-82893_CLASS_ID = -82893 FRAME_-82893_CENTER = -82 TKFRAME_-82893_SPEC = 'ANGLES' TKFRAME_-82893_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82893_ANGLES = ( 0.0, -90.0, 0.0 ) TKFRAME_-82893_AXES = ( 3, 1, 2 ) TKFRAME_-82893_UNITS = 'DEGREES' ECR 100515 [39] included mounting alignment updates for all CIRS focal planes. The optical boresight has moved from it's nominal configuration of the -Y axis in the spacecraft frame 1.7 milliradians towards +X and -0.04 milliradians towards -Z. The rotation matrix that takes vectors represented in the CIRS_FPB frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ -90.002291831180 ] [ -0.09740282517 ] [ ] [ ] [ ] [ ] Z X Y where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_CIRS_FPB = -82893 FRAME_-82893_NAME = 'CASSINI_CIRS_FPB' FRAME_-82893_CLASS = 4 FRAME_-82893_CLASS_ID = -82893 FRAME_-82893_CENTER = -82 TKFRAME_-82893_SPEC = 'ANGLES' TKFRAME_-82893_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82893_ANGLES = ( 0.0 -90.0022918311805233 -0.097402825172240, ) TKFRAME_-82893_AXES = ( 3, 1, 2 ) TKFRAME_-82893_UNITS = 'DEGREES' \begintext Composite Infrared Spectrometer Focal Plane #1 (CIRS_FP1) The CIRS FP1 points nominally along the spacecraft -Y axis. The following frame definition encapsulates this nominal frame. Nominal Frame Definition: FRAME_CASSINI_CIRS_FP1 = -82890 FRAME_-82890_NAME = 'CASSINI_CIRS_FP1' FRAME_-82890_CLASS = 4 FRAME_-82890_CLASS_ID = -82890 FRAME_-82890_CENTER = -82 TKFRAME_-82890_SPEC = 'ANGLES' TKFRAME_-82890_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82890_ANGLES = ( -90.0, 0.0, 90.0 ) TKFRAME_-82890_AXES = ( 1, 2, 3 ) TKFRAME_-82890_UNITS = 'DEGREES' [9] and [10] describe the most up to date values the orientation of the CIRS focal planes. The rotation matrix that takes vectors represented in the CIRS_FP1 frame into the CIRS_FPB frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ 0.23319382 ] [ ] [ ] [ ] [ ] Z X Y where [x] represents the rotation matrix of a given angle x about i axis i. The angles were computed from [10]. FRAME_CASSINI_CIRS_FP1 = -82890 FRAME_-82890_NAME = 'CASSINI_CIRS_FP1' FRAME_-82890_CLASS = 4 FRAME_-82890_CLASS_ID = -82890 FRAME_-82890_CENTER = -82 TKFRAME_-82890_SPEC = 'ANGLES' TKFRAME_-82890_RELATIVE = 'CASSINI_CIRS_FPB' TKFRAME_-82890_ANGLES = ( 0.0, 0.0, -0.23319382 ) TKFRAME_-82890_AXES = ( 3, 1, 2 ) TKFRAME_-82890_UNITS = 'DEGREES' [39] introduces new offsets for the FP1 from the optical boresight (FPB). They are: 3.98 milliradians towards +X in the spacecraft frame and 0.07 milliradians towards +Z in the spacecraft frame. These offsets result in the following rotation matrix: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0040107045659 ] [ -0.22803720246 ] [ ] [ ] [ ] [ ] Z X Y where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_CIRS_FP1 = -82890 FRAME_-82890_NAME = 'CASSINI_CIRS_FP1' FRAME_-82890_CLASS = 4 FRAME_-82890_CLASS_ID = -82890 FRAME_-82890_CENTER = -82 TKFRAME_-82890_SPEC = 'ANGLES' TKFRAME_-82890_RELATIVE = 'CASSINI_CIRS_FPB' TKFRAME_-82890_ANGLES = ( 0.0, 4.0107045659158E-03, -2.2803720246207E-01 ) TKFRAME_-82890_AXES = ( 3, 1, 2 ) TKFRAME_-82890_UNITS = 'DEGREES' \begintext Composite Infrared Spectrometer Focal Plane #3 (CIRS_FP3) The CIRS FP3 points nominally along the spacecraft -Y axis. The following frame definition encapsulates this nominal frame. Nominal Frame Definition: FRAME_CASSINI_CIRS_FP3 = -82891 FRAME_-82891_NAME = 'CASSINI_CIRS_FP3' FRAME_-82891_CLASS = 4 FRAME_-82891_CLASS_ID = -82891 FRAME_-82891_CENTER = -82 TKFRAME_-82891_SPEC = 'ANGLES' TKFRAME_-82891_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82891_ANGLES = ( -90.0, 0.0, 90.0 ) TKFRAME_-82891_AXES = ( 1, 2, 3 ) TKFRAME_-82891_UNITS = 'DEGREES' [9] and [10] describe the most up to date values the orientation of the CIRS focal planes. The rotation matrix that takes vectors represented in the CIRS_FP3 frame into the CIRS_FPB frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ 0.002549662 ] [ ] [ ] [ ] [ ] Z X Y where [x] represents the rotation matrix of a given angle x about i axis i. The angles were computed from [10] with updates from [15]. FRAME_CASSINI_CIRS_FP3 = -82891 FRAME_-82891_NAME = 'CASSINI_CIRS_FP3' FRAME_-82891_CLASS = 4 FRAME_-82891_CLASS_ID = -82891 FRAME_-82891_CENTER = -82 TKFRAME_-82891_SPEC = 'ANGLES' TKFRAME_-82891_RELATIVE = 'CASSINI_CIRS_FPB' TKFRAME_-82891_ANGLES = ( 0.0, 0.0, 0.02549662 ) TKFRAME_-82891_AXES = ( 3, 1, 2 ) TKFRAME_-82891_UNITS = 'DEGREES' [39] includes an update to the offset of CASSINI_CIRS_FP3 from CASSINI_CIRS_FPB. Instead of 0.445 milliradians, the new value is 0.47 milliradians of separation between the optical boresight and focal plane 3's boresight. The rotation matrix that takes vectors represented in the CIRS_FP3 frame into the CIRS_FPB frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ 0.002692902 ] [ ] [ ] [ ] [ ] Z X Y where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_CIRS_FP3 = -82891 FRAME_-82891_NAME = 'CASSINI_CIRS_FP3' FRAME_-82891_CLASS = 4 FRAME_-82891_CLASS_ID = -82891 FRAME_-82891_CENTER = -82 TKFRAME_-82891_SPEC = 'ANGLES' TKFRAME_-82891_RELATIVE = 'CASSINI_CIRS_FPB' TKFRAME_-82891_ANGLES = ( 0.0, 0.0, 2.6929016371149E-02 ) TKFRAME_-82891_AXES = ( 3, 1, 2 ) TKFRAME_-82891_UNITS = 'DEGREES' \begintext Composite Infrared Spectrometer Focal Plane #4 (CIRS_FP4) The CIRS FP4 points nominally along the spacecraft -Y axis. The following frame definition encapsulates this nominal frame. Nominal Frame Definition: FRAME_CASSINI_CIRS_FP4 = -82892 FRAME_-82892_NAME = 'CASSINI_CIRS_FP4' FRAME_-82892_CLASS = 4 FRAME_-82892_CLASS_ID = -82892 FRAME_-82892_CENTER = -82 TKFRAME_-82892_SPEC = 'ANGLES' TKFRAME_-82892_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82892_ANGLES = ( -90.0, 0.0, 90.0 ) TKFRAME_-82892_AXES = ( 1, 2, 3 ) TKFRAME_-82892_UNITS = 'DEGREES' [9] and [10] describe the most up to date values the orientation of the CIRS focal planes. The rotation matrix that takes vectors represented in the CIRS_FP4 frame into the CIRS_FPB frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -0.02549662 ] [ ] [ ] [ ] [ ] Z X Y where [x] represents the rotation matrix of a given angle x about i axis i. The angles were taken directly from [10] with updates from [15]. FRAME_CASSINI_CIRS_FP4 = -82892 FRAME_-82892_NAME = 'CASSINI_CIRS_FP4' FRAME_-82892_CLASS = 4 FRAME_-82892_CLASS_ID = -82892 FRAME_-82892_CENTER = -82 TKFRAME_-82892_SPEC = 'ANGLES' TKFRAME_-82892_RELATIVE = 'CASSINI_CIRS_FPB' TKFRAME_-82892_ANGLES = ( 0.0, 0.0, -0.02549662 ) TKFRAME_-82892_AXES = ( 3, 1, 2 ) TKFRAME_-82892_UNITS = 'DEGREES' [39] includes an update to the offset of CASSINI_CIRS_FP4 from CASSINI_CIRS_FPB. Instead of 0.445 milliradians, the new value is 0.47 milliradians of separation between the optical boresight and focal plane 4's boresight. The rotation matrix that takes vectors represented in the CIRS_FP4 frame into the CIRS_FPB frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -0.002692902 ] [ ] [ ] [ ] [ ] Z X Y where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_CIRS_FP4 = -82892 FRAME_-82892_NAME = 'CASSINI_CIRS_FP4' FRAME_-82892_CLASS = 4 FRAME_-82892_CLASS_ID = -82892 FRAME_-82892_CENTER = -82 TKFRAME_-82892_SPEC = 'ANGLES' TKFRAME_-82892_RELATIVE = 'CASSINI_CIRS_FPB' TKFRAME_-82892_ANGLES = ( 0.0, 0.0, -2.6929016371149E-02 ) TKFRAME_-82892_AXES = ( 3, 1, 2 ) TKFRAME_-82892_UNITS = 'DEGREES' \begintext CIRS Radiator (CIRS_RAD) The CIRS radiator is nominally oriented with its +Z axis directed down the spacecraft +X axis. Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. As [17] indicates, the CIRS_RAD boresight is nominally aligned with the +X axis in the spacecraft frame. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -90.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_CIRS_RAD = -82898 FRAME_-82898_NAME = 'CASSINI_CIRS_RAD' FRAME_-82898_CLASS = 4 FRAME_-82898_CLASS_ID = -82898 FRAME_-82898_CENTER = -82 TKFRAME_-82898_SPEC = 'ANGLES' TKFRAME_-82898_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82898_ANGLES = ( -90.0, -90.0, 0.0 ) TKFRAME_-82898_AXES = ( 3, 1, 3 ) TKFRAME_-82898_UNITS = 'DEGREES' \begintext UVIS Frames ---------------------------------------------------------- The Ultraviolet Imaging Spectrograph (UVIS) is mounted on the remote sensing pallet on the +X side of the Cassini spacecraft, and nominally directed along the -Y axis of the AACS body frame. Note the angles in the frame definitions are specified for the "from instrument to (relative to) base frame" transformation. Ultraviolet Imaging Spectrograph Far Ultraviolet Spectrograph (UVIS_FUV) An examination of [5] reveals that UVIS_FUV points nominally along the spacecraft -Y axis. The rotation matrix that takes vectors represented in the UVIS_FUV frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -90.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. The following frame definition describes this nominal frame: Nominal Frame Definition: FRAME_CASSINI_UVIS_FUV = -82840 FRAME_-82840_NAME = 'CASSINI_UVIS_FUV' FRAME_-82840_CLASS = 4 FRAME_-82840_CLASS_ID = -82840 FRAME_-82840_CENTER = -82 TKFRAME_-82840_SPEC = 'ANGLES' TKFRAME_-82840_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82840_ANGLES = ( 0.0, 0.0, -90.0 ) TKFRAME_-82840_AXES = ( 3, 2, 1 ) TKFRAME_-82840_UNITS = 'DEGREES' From [40], the UVIS_FUV boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0002 ] UVIS_FUV Boresight Vector = [ -0.99999998 ] [ 0.0001 ] This leads to the following rotation matrix that takes vectors represented in the UVIS_FUV frame into the spacecraft frame: [ ] [ ] [ ] [ ] [ ROT ] = [ -89.9999 ] [ -0.011459 ] [ 0.005729 ] [ ] [ ] [ ] [ ] X Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_UVIS_FUV = -82840 FRAME_-82840_NAME = 'CASSINI_UVIS_FUV' FRAME_-82840_CLASS = 4 FRAME_-82840_CLASS_ID = -82840 FRAME_-82840_CENTER = -82 TKFRAME_-82840_SPEC = 'ANGLES' TKFRAME_-82840_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82840_ANGLES = ( -89.999999, -0.01145916, 0.005729578 ) TKFRAME_-82840_AXES = ( 1, 2, 1 ) TKFRAME_-82840_UNITS = 'DEGREES' \begintext Ultraviolet Imaging Spectrograph Extreme Ultraviolet Spectrograph (UVIS_EUV) An examination of [5] reveals that the UVIS_EUV points nominally along the spacecraft -Y axis. The rotation matrix that takes vectors represented in the UVIS_EUV frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -90.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. The following frame definition describes this nominal frame: Nominal Frame Definition: FRAME_CASSINI_UVIS_EUV = -82842 FRAME_-82842_NAME = 'CASSINI_UVIS_EUV' FRAME_-82842_CLASS = 4 FRAME_-82842_CLASS_ID = -82842 FRAME_-82842_CENTER = -82 TKFRAME_-82842_SPEC = 'ANGLES' TKFRAME_-82842_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82842_ANGLES = ( 0.0, 0.0, -90.0 ) TKFRAME_-82842_AXES = ( 3, 2, 1 ) TKFRAME_-82842_UNITS = 'DEGREES' From [40], the UVIS_EUV boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0012 ] UVIS_EUV Boresight Vector = [ -0.99999843 ] [ 0.0013 ] This leads to the following rotation matrix that takes vectors represented in the UVIS_EUV frame into the spacecraft frame: [ ] [ ] [ ] [ ] [ ROT ] = [ -89.8984 ] [ -0.068755 ] [ -0.02704 ] [ ] [ ] [ ] [ ] X Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_UVIS_EUV = -82842 FRAME_-82842_NAME = 'CASSINI_UVIS_EUV' FRAME_-82842_CLASS = 4 FRAME_-82842_CLASS_ID = -82842 FRAME_-82842_CENTER = -82 TKFRAME_-82842_SPEC = 'ANGLES' TKFRAME_-82842_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82842_ANGLES = ( -89.8984716, -0.068755, -0.027044457 ) TKFRAME_-82842_AXES = ( 1, 2, 1 ) TKFRAME_-82842_UNITS = 'DEGREES' \begintext Ultraviolet Imaging Spectrograph Solar Occultation Port (UVIS_SOLAR) [29] and [30] indicate that the UVIS solar occultation port points nominally 20 degrees offset from the nominal UVIS boresights in the -Y direction of the nominal instrument frames. The rotation matrix that takes vectors represented in the CASSINI_UVIS_SOLAR frame into the CASSINI_SC_COORD frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -110.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_UVIS_SOLAR = -82843 FRAME_-82843_NAME = 'CASSINI_UVIS_SOLAR' FRAME_-82843_CLASS = 4 FRAME_-82843_CLASS_ID = -82843 FRAME_-82843_CENTER = -82 TKFRAME_-82843_SPEC = 'ANGLES' TKFRAME_-82843_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82843_ANGLES = ( 0.0, 0.0, -110.0 ) TKFRAME_-82843_AXES = ( 3, 2, 1 ) TKFRAME_-82843_UNITS = 'DEGREES' \begintext Ultraviolet Imaging Spectrograph High Speed Photometer (UVIS_HSP) An examination of [5] reveals that the UVIS_HSP points nominally along the spacecraft -Y axis. The rotation matrix that takes vectors represented in the UVIS_HSP frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -90.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. The following frame definition describes this nominal frame: Nominal Frame Definition: FRAME_CASSINI_UVIS_HSP = -82844 FRAME_-82844_NAME = 'CASSINI_UVIS_HSP' FRAME_-82844_CLASS = 4 FRAME_-82844_CLASS_ID = -82844 FRAME_-82844_CENTER = -82 TKFRAME_-82844_SPEC = 'ANGLES' TKFRAME_-82844_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82844_ANGLES = ( 0.0, 0.0, -90.0 ) TKFRAME_-82844_AXES = ( 3, 2, 1 ) TKFRAME_-82844_UNITS = 'DEGREES' From [40], the UVIS_HSP boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0012 ] UVIS_HSP Boresight Vector = [ -0.99999856 ] [ -0.0012 ] This leads to the following rotation matrix that takes vectors represented in the UVIS_HSP frame into the spacecraft frame: [ ] [ ] [ ] [ ] [ ROT ] = [ -89.9028 ] [ -0.068755 ] [ -0.16599 ] [ ] [ ] [ ] [ ] X Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_UVIS_HSP = -82844 FRAME_-82844_NAME = 'CASSINI_UVIS_HSP' FRAME_-82844_CLASS = 4 FRAME_-82844_CLASS_ID = -82844 FRAME_-82844_CENTER = -82 TKFRAME_-82844_SPEC = 'ANGLES' TKFRAME_-82844_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82844_ANGLES = ( -89.9027658, -0.068755, -0.1659861 ) TKFRAME_-82844_AXES = ( 1, 2, 1 ) TKFRAME_-82844_UNITS = 'DEGREES' \begintext Ultraviolet Imaging Spectrograph Hydrogen - Deuterium Absorption Cell (UVIS_HDAC) An examination of [5] reveals that the UVIS_HDAC points nominally along the spacecraft -Y axis. The rotation matrix that takes vectors represented in the UVIS_HSP frame into the spacecraft frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -90.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. The following frame definition describes this nominal frame: \begindata FRAME_CASSINI_UVIS_HDAC = -82845 FRAME_-82845_NAME = 'CASSINI_UVIS_HDAC' FRAME_-82845_CLASS = 4 FRAME_-82845_CLASS_ID = -82845 FRAME_-82845_CENTER = -82 TKFRAME_-82845_SPEC = 'ANGLES' TKFRAME_-82845_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82845_ANGLES = ( 0.0, 0.0, -90.0 ) TKFRAME_-82845_AXES = ( 3, 2, 1 ) TKFRAME_-82845_UNITS = 'DEGREES' \begintext VIMS Frames ---------------------------------------------------------- The Visible and Infrared Mapping Spectrometer is mounted on the remote sensing pallet on the +X side of the Cassini spacecraft, and nominally directed along the -Y axis of the AACS body frame. Note the angles in the frame definitions are specified for the ``from instrument to (relative to) base frame'' transformation. Visible and Infrared Mapping Spectrometer Visible (VIMS_V) The VIMS_V detector points nominally along the spacecraft -Y axis. The following frame definition encapsulates this nominal frame. From [13]: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -90.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_VIMS_V = -82370 FRAME_-82370_NAME = 'CASSINI_VIMS_V' FRAME_-82370_CLASS = 4 FRAME_-82370_CLASS_ID = -82370 FRAME_-82370_CENTER = -82 TKFRAME_-82370_SPEC = 'ANGLES' TKFRAME_-82370_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82370_ANGLES = ( 0.0, 0.0, -90.0 ) TKFRAME_-82370_AXES = ( 3, 2, 1 ) TKFRAME_-82370_UNITS = 'DEGREES' \begintext Visible and Infrared Mapping Spectrometer Infrared (VIMS_IR) The VIMS_IR detector points nominally along the spacecraft -Y axis. The following frame definition encapsulates this nominal frame. From [13]: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -90.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: FRAME_CASSINI_VIMS_IR = -82371 FRAME_-82371_NAME = 'CASSINI_VIMS_IR' FRAME_-82371_CLASS = 4 FRAME_-82371_CLASS_ID = -82371 FRAME_-82371_CENTER = -82 TKFRAME_-82371_SPEC = 'ANGLES' TKFRAME_-82371_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82371_ANGLES = ( 0.0, 0.0, -90.0 ) TKFRAME_-82371_AXES = ( 3, 2, 1 ) TKFRAME_-82371_UNITS = 'DEGREES' From [41], the VIMS_IR boresight has been adjusted to the following vector in spacecraft coordinates: [ 0.0021251 ] VIMS_IR Boresight Vector = [ -0.9999974 ] [ -0.0008495 ] Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -360.121759 ] [ -90.0486727 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_VIMS_IR = -82371 FRAME_-82371_NAME = 'CASSINI_VIMS_IR' FRAME_-82371_CLASS = 4 FRAME_-82371_CLASS_ID = -82371 FRAME_-82371_CENTER = -82 TKFRAME_-82371_SPEC = 'ANGLES' TKFRAME_-82371_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82371_ANGLES = ( -360.12175939433, -90.048672769633, 0.0 ) TKFRAME_-82371_AXES = ( 3, 1, 3 ) TKFRAME_-82371_UNITS = 'DEGREES' \begintext Visible and Infrared Mapping Spectrometer Infrared Solar Port (VIMS_IR_SOL) [28] indicates that the VIMS IR channel solar port points nominally 20 degrees offset from the VIMS IR boresight in the -Y direction of the VIMS_IR frame. The rotation matrix that takes vectors represented in the VIMS_IR_SOL frame into the VIMS_IR frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ -20.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. FRAME_CASSINI_VIMS_IR_SOL = -82372 FRAME_-82372_NAME = 'CASSINI_VIMS_IR_SOL' FRAME_-82372_CLASS = 4 FRAME_-82372_CLASS_ID = -82372 FRAME_-82372_CENTER = -82 TKFRAME_-82372_SPEC = 'ANGLES' TKFRAME_-82372_RELATIVE = 'CASSINI_VIMS_IR' TKFRAME_-82372_ANGLES = ( 0.0, 0.0, -20.0 ) TKFRAME_-82372_AXES = ( 3, 2, 1 ) TKFRAME_-82372_UNITS = 'DEGREES' [42] requested that CASSINI_VIMS_IR_SOL be referenced directly to CASSINI_SC_COORD. In addition, [42], [43], and [45] also carry updates to the alignment of the solar port. The rotation matrix that takes vectors represented in the VIMS_IR_SOL frame into the CASSINI_SC_COORD frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0859436686699 ] [ 0.0 ] [ -110.630253571 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_VIMS_IR_SOL = -82372 FRAME_-82372_NAME = 'CASSINI_VIMS_IR_SOL' FRAME_-82372_CLASS = 4 FRAME_-82372_CLASS_ID = -82372 FRAME_-82372_CENTER = -82 TKFRAME_-82372_SPEC = 'ANGLES' TKFRAME_-82372_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82372_ANGLES = ( 0.085943668669984, 0.0, -110.63025357166 ) TKFRAME_-82372_AXES = ( 3, 2, 1 ) TKFRAME_-82372_UNITS = 'DEGREES' \begintext Visible and Infrared Mapping Spectrometer Radiator (VIMS_RAD) The VIMS radiator is nominally oriented with its +Z axis directed down the spacecraft +X axis. This is not the case for the radiator plate itself, which is mounted in the housing such that it is canted by 28.05 degrees. In the spacecraft coordinate frame, the cant is towards the spacecraft -Y axis. This, however, is not the end of the story. Thermally, the radiator housing and the radiator plate have interaction with respect to solar heating so that the effective boresight for symmetric solar heating, regardless of direction, is not offset by 28.05 degrees from the spacecraft +X axis. Initially the +Z axis of the radiator frame was determined to be the +X axis of the spacecraft frame. This results in the following: Since only boresight information has been provided, the frame transformation outlined below was constructed by computing the RA and DEC of the boresight vector relative to the CASSINI_SC_COORD frame. These angles are then utilized in the following fashion to construct the frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -(RA+90) ] [ -(90-DEC) ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. This produces a frame whose Z-axis agrees with the specified boresight. As [17] indicates, the VIMS_RAD boresight is nominally aligned with the +X axis in the spacecraft frame. By the methodology outlined above, this produces the following frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ -90.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: FRAME_CASSINI_VIMS_RAD = -82378 FRAME_-82378_NAME = 'CASSINI_VIMS_RAD' FRAME_-82378_CLASS = 4 FRAME_-82378_CLASS_ID = -82378 FRAME_-82378_CENTER = -82 TKFRAME_-82378_SPEC = 'ANGLES' TKFRAME_-82378_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82378_ANGLES = ( -90.0, -90.0, 0.0 ) TKFRAME_-82378_AXES = ( 3, 1, 3 ) TKFRAME_-82378_UNITS = 'DEGREES' From [36]: A solar heating analysis and identification of a solar heating ``effective'' radiator boresight was performed for ECR 100325-B covering Flight Rule FF37B2 [37]. The solar heating analysis identified that a VIMS radiator boresight offset from the spacecraft +X axis in the direction of the spacecraft -Y axis by 4.5 degrees would define a thermally ``effective'' boresight. To implement this change, the rotation about the Z-axis needs to be increased by 4.5 degrees as follows: [ ] [ ] [ ] [ ] [ ROT ] = [ -85.5 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z X Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_VIMS_RAD = -82378 FRAME_-82378_NAME = 'CASSINI_VIMS_RAD' FRAME_-82378_CLASS = 4 FRAME_-82378_CLASS_ID = -82378 FRAME_-82378_CENTER = -82 TKFRAME_-82378_SPEC = 'ANGLES' TKFRAME_-82378_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82378_ANGLES = ( -85.5, -90.0, 0.0 ) TKFRAME_-82378_AXES = ( 3, 1, 3 ) TKFRAME_-82378_UNITS = 'DEGREES' \begintext CAPS Frames ---------------------------------------------------------- The Cassini Plasma Spectrometer is mounted on an actuator which is in turn attached to the fields and particles pallet which is roughly located on the -X side of the Cassini spacecraft. The actuator allows the instrument to articulate, so to make proper use of this frame requires a C-kernel (or set of C-kernels) with appropriate coverage for the epochs of interest. To connect the CASSINI_CAPS frame with the spacecraft coordinate frame (CASSINI_SC_COORD) two possible branches exist depending on the set of C-kernels loaded: CASSINI_SC_COORD CASSINI_SC_COORD ---------------- ---------------- | | |<--- fixed offset | | | V | CASSINI_CAPS_BASE | ----------------- | | | |<--- c-kernel |<--- c-kernel | | V | CASSINI_CAPS_ART | ---------------- | | | |<--- c-kernel | | | V V CASSINI_CAPS CASSINI_CAPS ------------ ------------ The branch illustrated on the left of the figure above utilizes a series of transformations to connect the spacecraft frame with the instrument frame. The general strategy in this branch is the following: -- Define a fixed offset frame that connects the spacecraft frame to the base or 'zero-point' of the articulation of the instrument. -- Define a C-kernel based frame to perform the rotation about the articulation axis. -- Define a C-kernel based frame that performs the final rotation necessary to produce the instrument frame. This last frame in the absence of the right branch could be another fixed offset frame. However, making it a C-kernel allows the branch on the right to exist. This alternate route up the frame tree allows the construction and use of C-kernels that tie the instrument frame directly back to the spacecraft frame. This is often convenient for science data analysis. Without further ado, the frame defintions: Cassini Plasma Spectrometer Zero-Articulation Base Frame (CAPS_BASE) The Z-axis of this frame is the articulation axis of CAPS. The X-axis is constructed by taking the vector product of the CAPS articulation axis with the boresight in the 'zero-angle' or base position. The Y-axis completes the right handed frame. The articulation axis of CAPS is the Z-axis of CASSINI_SC_COORD, and the boresight in its 'zero-angle' configuration is the negative Y-axis of this spacecraft frame, so we end up with the following: The rotation matrix that takes vectors represented in the CAPS_BASE frame into the spacecraft coordinate frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 0.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_CAPS_BASE = -82822 FRAME_-82822_NAME = 'CASSINI_CAPS_BASE' FRAME_-82822_CLASS = 4 FRAME_-82822_CLASS_ID = -82822 FRAME_-82822_CENTER = -82 TKFRAME_-82822_SPEC = 'ANGLES' TKFRAME_-82822_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82822_ANGLES = ( 0.0, 0.0, 0.0 ) TKFRAME_-82822_AXES = ( 3, 2, 1 ) TKFRAME_-82822_UNITS = 'DEGREES' \begintext Cassini Plasma Spectrometer Articulation Frame (CAPS_ART) The Z-axis of this frame is the articulation axis of CAPS. The X-axis is constructed by taking the vector product of the CAPS articulation axis with the boresight at some articulated position. The Y-axis completes the right handed frame. This frame encapsulates the articulation characteristics of the CAPS instrument. To make use of it requires a C-kernel with coverage at the epochs of interest be loaded. The rotation matrix that takes vectors from the CAPS_ART frame to the CAPS_BASE frame follows: [ ] [ ] [ ROT ] = [ ANGLE ] [ ] [ ] Z where [x] represents the rotation matrix of a given angle x about i axis i, and ANGLE is the articulation angle. \begindata FRAME_CASSINI_CAPS_ART = -82821 FRAME_-82821_NAME = 'CASSINI_CAPS_ART' FRAME_-82821_CLASS = 3 FRAME_-82821_CLASS_ID = -82821 FRAME_-82821_CENTER = -82 CK_-82821_SCLK = -82 CK_-82821_SPK = -82 \begintext Cassini Plasma Spectrometer Frame (CAPS) The negative Y-axis of this frame is the instrument boresight. The Z-axis is defined as the articulation axis of the detectors, and the X-axis completes the right handed frame. This frame requires one of two possible C-kernels: -- One kernel connects this instrument frame (-82820) directly to the spacecraft frame (-82000). -- The other possible kernel connects this instrument frame (-82820) to the articulation frame (-82821) defined above. The kernel that makes this connection for all epochs after launch is delivered with the kernel set. See the kernel comments for details of frame construction. One should take care in the simultaneous loading of C-kernels that utilize different paths of the frame tree to connect CASSINI_CAPS to CASSINI_SC_COORD. See [1] for details regarding C-kernel precedence. \begindata FRAME_CASSINI_CAPS = -82820 FRAME_-82820_NAME = 'CASSINI_CAPS' FRAME_-82820_CLASS = 3 FRAME_-82820_CLASS_ID = -82820 FRAME_-82820_CENTER = -82 CK_-82820_SCLK = -82 CK_-82820_SPK = -82 \begintext CDA Frames ---------------------------------------------------------- The Cosmic Dust Analyzer is mounted on the -X side of the Cassini spacecraft. The entire assembly is capable of articulating from it's zero angle position. The following describes the boresight in the spacecraft frame as a function of the articulation angle a: From [18]: x = 1/8 ( -1 - SQRT(3) + (-1 + SQRT(3)) COS(a) - 2 SQRT(6) SIN(a) ) y = 1/8 ( 3 + SQRT(3) + (-3 + SQRT(3)) COS(a) - 2 SQRT(2) SIN(a) ) z = 1/4 ( -1 + SQRT(3) + ( 1 + SQRT(3)) COS(a) ) The actuator allows the instrument to articulate, so to make proper use of this frame requires a C-kernel (or set of C-kernels) with appropriate coverage for the epochs of interest. To connect the CASSINI_CDA frame with the spacecraft coordinate frame (CASSINI_SC_COORD) two possible branches exist depending on the set of C-kernels loaded: CASSINI_SC_COORD CASSINI_SC_COORD ---------------- ---------------- | | |<--- fixed offset | | | V | CASSINI_CDA_BASE | ---------------- | | | |<--- c-kernel |<--- c-kernel | | V | CASSINI_CDA_ART | --------------- | | | |<--- c-kernel | | | V V CASSINI_CDA CASSINI_CDA ----------- ----------- The branch illustrated on the left of the figure above utilizes a series of transformations to connect the spacecraft frame with the instrument frame. The general strategy in this branch is the following: -- Define a fixed offset frame that connects the spacecraft frame to the base or 'zero-point' of the articulation of the instrument. -- Define a C-kernel based frame to perform the rotation about the articulation axis. -- Define a C-kernel based frame that performs the final rotation necessary to produce the instrument frame. This last frame in the absence of the right branch could be another fixed offset frame. However, making it a C-kernel allows the branch on the right to exist. This alternate route up the frame tree allows the construction and use of C-kernels that tie the instrument frame directly back to the spacecraft frame. This is often convenient for science data analysis. Without further ado, the frame defintions: Cosmic Dust Analyzer Zero-Articulation Base Frame (CDA_BASE) The Z-axis of this frame is the articulation axis of CDA. The X-axis is constructed by taking the vector product of the CDA articulation axis with the boresight in the 'zero-angle' or base position. The Y-axis completes the right handed frame. An examination of the relationship connecting the boresight position in the spacecraft frame with the articulation angle, yields the following: The articulation axis of CDA in CASSINI_SC_COORD is: (+4.8296291314453E-01, -8.3651630373781E-01, -2.5881904510252E-01) The 'zero-angle' boresight in CASSINI_SC_COORD is: (-2.5000000000000E-01, 4.3301270189222E-01, 8.6602540378444E-01) The articulation axis points in the opposite direction of the cone swept out by the boresight vectors. This was done to preserve the sense of the positive angle in the definition provided in [18]. Computing the frame described above we end up with: The rotation matrix that takes vectors represented in the CDA_BASE frame into the spacecraft coordinate frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 150.0 ] [ 0.0 ] [ 105.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_CDA_BASE = -82792 FRAME_-82792_NAME = 'CASSINI_CDA_BASE' FRAME_-82792_CLASS = 4 FRAME_-82792_CLASS_ID = -82792 FRAME_-82792_CENTER = -82 TKFRAME_-82792_SPEC = 'ANGLES' TKFRAME_-82792_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82792_ANGLES = ( 150.0, 0.0, 105.0 ) TKFRAME_-82792_AXES = ( 3, 2, 1 ) TKFRAME_-82792_UNITS = 'DEGREES' \begintext Cosmic Dust Analyzer Articulation Frame (CDA_ART) The Z-axis of this frame is the articulation axis of CDA. The X-axis is constructed by taking the vector product of the CDA articulation axis with the boresight at some articulated position. The Y-axis completes the right handed frame. This frame encapsulates the articulation characteristics of the CDA instrument. To make use of it requires a C-kernel with coverage at the epochs of interest be loaded. The rotation matrix that takes vectors from the CDA_ART frame to the CDA_BASE frame follows: [ ] [ ] [ ROT ] = [ ANGLE ] [ ] [ ] Z where [x] represents the rotation matrix of a given angle x about i axis i, and ANGLE is the articulation angle. \begindata FRAME_CASSINI_CDA_ART = -82791 FRAME_-82791_NAME = 'CASSINI_CDA_ART' FRAME_-82791_CLASS = 3 FRAME_-82791_CLASS_ID = -82791 FRAME_-82791_CENTER = -82 CK_-82791_SCLK = -82 CK_-82791_SPK = -82 \begintext Cosmic Dust Analyzer Frame (CDA) The Z-axis of this frame is the instrument boresight. The X-axis of is the same as the X-axis of CASSINI_CDA_ART, and the Y-axis completes the right handed frame. This frame requires one of two possible C-kernels: -- One kernel connects this instrument frame (-82790) directly to the spacecraft frame (-82000). -- The other possible kernel connects this instrument frame (-82790) to the articulation frame (-82791) defined above. The kernel that makes this connection for all epochs after launch is delivered with the kernel set. See the kernel comments for details of frame construction. One should take care in the simultaneous loading of C-kernels that utilize different paths of the frame tree to connect CASSINI_CDA to CASSINI_SC_COORD. See [1] for details regarding C-kernel precedence. \begindata FRAME_CASSINI_CDA = -82790 FRAME_-82790_NAME = 'CASSINI_CDA' FRAME_-82790_CLASS = 3 FRAME_-82790_CLASS_ID = -82790 FRAME_-82790_CENTER = -82 CK_-82790_SCLK = -82 CK_-82790_SPK = -82 \begintext INMS Frames ---------------------------------------------------------- The Ion and Neutral Mass Spectrometer is mounted on the fields and particles pallet roughly located on the -X side of the Cassini spacecraft. The instrument boresight is nominally directed along the -X axis of the AACS body frame. Note the angles in the frame definitions are specified for the ``from instrument to (relative to) base frame'' transformation. From [19], we have the following nominal frame definition: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ +90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] x Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_INMS = -82740 FRAME_-82740_NAME = 'CASSINI_INMS' FRAME_-82740_CLASS = 4 FRAME_-82740_CLASS_ID = -82740 FRAME_-82740_CENTER = -82 TKFRAME_-82740_SPEC = 'ANGLES' TKFRAME_-82740_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82740_ANGLES = ( 0.0, +90.0, 0.0 ) TKFRAME_-82740_AXES = ( 1, 2, 3 ) TKFRAME_-82740_UNITS = 'DEGREES' \begintext MAG Frames ---------------------------------------------------------- The Magnetometer is mounted on the magentometer boom which protrudes from the spacecraft body in the direction of the +Y axis of the AACS body frame. [20] establishes the need for two separate frame definitions, one for the Plus-X directed frame, the other for the Minux-X one. Note the angles in the frame definitions are specified for the ``from instrument to (relative to) base frame'' transformation. Magnetometer Plus-X (MAG_PLUS) The MAG_PLUS detector is pointed nominally in the direction of the spacecraft +X axis. The following definition encapsulates this frame: From [21]: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_MAG_PLUS = -82350 FRAME_-82350_NAME = 'CASSINI_MAG_PLUS' FRAME_-82350_CLASS = 4 FRAME_-82350_CLASS_ID = -82350 FRAME_-82350_CENTER = -82 TKFRAME_-82350_SPEC = 'ANGLES' TKFRAME_-82350_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82350_ANGLES = ( 0.0, -90.0, 0.0 ) TKFRAME_-82350_AXES = ( 1, 2, 3 ) TKFRAME_-82350_UNITS = 'DEGREES' \begintext Magnetometer Minus-X (MAG_MINUS) The MAG_MINUS detector is pointed nominally in the direction of the spacecraft -X axis. The following definition encapsulates this frame: From [21]: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_MAG_MINUS = -82351 FRAME_-82351_NAME = 'CASSINI_MAG_MINUS' FRAME_-82351_CLASS = 4 FRAME_-82351_CLASS_ID = -82351 FRAME_-82351_CENTER = -82 TKFRAME_-82351_SPEC = 'ANGLES' TKFRAME_-82351_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82351_ANGLES = ( 0.0, 90.0, 0.0 ) TKFRAME_-82351_AXES = ( 1, 2, 3 ) TKFRAME_-82351_UNITS = 'DEGREES' \begintext MIMI Frames ---------------------------------------------------------- Most of the components of the Magnetospheric Imaging Instrument are mounted on the fields and particles pallet roughly located on the -X side of the Cassini spacecraft. The one exception is the Ion and Neutral Camera which is mounted on the -Y side of the orbiter. Note the angles in the frame definitions are specified for the ``from instrument to (relative to) base frame'' transformation. Magnetospheric Imaging Instrument Charge Energy Mass Spectrometer (MIMI_CHEMS) The MIMI_CHEMS detector is nominally pointed along the -X axis of the spacecraft frame. The following definition encapsulates this frame: From [17]: [ ] [ ] [ ] [ ] [ ROT ] = [ 0.0 ] [ 90.0 ] [ 90.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_MIMI_CHEMS = -82760 FRAME_-82760_NAME = 'CASSINI_MIMI_CHEMS' FRAME_-82760_CLASS = 4 FRAME_-82760_CLASS_ID = -82760 FRAME_-82760_CENTER = -82 TKFRAME_-82760_SPEC = 'ANGLES' TKFRAME_-82760_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82760_ANGLES = ( 0.0, 90.0, 90.0 ) TKFRAME_-82760_AXES = ( 1, 2, 3 ) TKFRAME_-82760_UNITS = 'DEGREES' \begintext Magnetospheric Imaging Instrument Ion and Neutral Camera (MIMI_INCA) The MIMI_INCA detector is nominally pointed along the -Y axis of the spacecraft frame with a 9.5 degree offset in the direction of the +X axis of the spacecraft. The following definition encapsulates this frame: From [22]: [ ] [ ] [ ] [ ] [ ROT ] = [ -90.0 ] [ -9.5 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_MIMI_INCA = -82761 FRAME_-82761_NAME = 'CASSINI_MIMI_INCA' FRAME_-82761_CLASS = 4 FRAME_-82761_CLASS_ID = -82761 FRAME_-82761_CENTER = -82 TKFRAME_-82761_SPEC = 'ANGLES' TKFRAME_-82761_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82761_ANGLES = ( -90.0, -9.5, 0.0 ) TKFRAME_-82761_AXES = ( 1, 2, 3 ) TKFRAME_-82761_UNITS = 'DEGREES' \begintext Magnetospheric Imaging Instrument Low Energy Magnetospheric Measurements (MIMI_LEMMS) The actuator allows the detectors to articulate, so to make proper use of this frame requires a C-kernel (or set of C-kernels) with appropriate coverage for the epochs of interest. To connect the CASSINI_MIMI_LEMMS1 and CASSINI_MIMI_LEMMS2 frames with the spacecraft coordinate frame (CASSINI_SC_COORD) two possible branches exist depending on the set of C-kernels loaded: CASSINI_SC_COORD CASSINI_SC_COORD ---------------- ---------------- | | | |<--- fixed offset | | | | | V | | CASSINI_MIMI_LEMMS_BASE | | ----------------------- | | | | | |<--- c-kernel |<--- c-kernel | | | | V | | CASSINI_MIMI_LEMMS_ART | | ---------------------- | | | | | | |<--- c-kernel | | c-kernel --->| | | | | V | V | CASSINI_MIMI_LEMMS1 | CASSINI_MIMI_LEMMS1 | ------------------- | ------------------- | | | c-kernel --->| | | | V V CASSINI_MIMI_LEMMS2 CASSINI_MIMI_LEMMS2 ------------------- ------------------- The branches illustrated on the left of the figure above utilize a series of transformations to connect the spacecraft frame with the detector frames. The general strategy in these branches is the following: -- Define a fixed offset frame that connects the spacecraft frame to the base or 'zero-point' of the articulation of the detectors. -- Define a C-kernel based frame to perform the rotation about the articulation axis. -- Define a C-kernel based frame that performs the final rotation necessary to produce either of the instrument frame. These last frames (MIMI_LEMMS1 and MIMI_LEMMS2) in the absence of the right branch could be another fixed offset frame. However, making them C-kernels allows the branches on the right to exist. This alternate route up the frame tree allows the construction and use of C-kernels that tie the individual detector frames directly back to the spacecraft frame. This is often convenient for science data analysis. Without further ado, the frame defintions: Magnetospheric Imaging Instrument Low Energy Magnetospheric Measurements Zero-Articulation Base Frame (MIMI_LEMMS_BASE) The Z-axis of this frame is the articulation axis of MIMI_LEMMS. The X-axis is constructed by taking the vector product of the MIMI_LEMMS articulation axis with the MIMI_LEMMS1 boresight in the 'zero-angle' or base position. The Y-axis completes the right handed frame. As [33] indicates, the articulation axis is the Y-axis in CASSINI_SC_COORD and the 'zero-angle' boresight of MIMI_LEMMS1 is the -Z-axis in CASSINI_SC_COORD. Combining this information with the frame definition laid out above, we have: The rotation matrix that takes vectors represented in the MIMI_LEMMS_BASE frame into the spacecraft coordinate frame follows: [ ] [ ] [ ] [ ] [ ROT ] = [ 180.0 ] [ 0.0 ] [ -90.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_MIMI_LEMMS_BASE = -82765 FRAME_-82765_NAME = 'CASSINI_MIMI_LEMMS_BASE' FRAME_-82765_CLASS = 4 FRAME_-82765_CLASS_ID = -82765 FRAME_-82765_CENTER = -82 TKFRAME_-82765_SPEC = 'ANGLES' TKFRAME_-82765_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82765_ANGLES = ( 180.0, 0.0, -90.0 ) TKFRAME_-82765_AXES = ( 3, 2, 1 ) TKFRAME_-82765_UNITS = 'DEGREES' \begintext Magnetospheric Imaging Instrument Low Energy Magnetospheric Measurements Articulation Frame (MIMI_LEMMS_ART) The Z-axis of this frame is the articulation axis of MIMI_LEMMS. The X-axis is constructed by taking the vector product of the MIMI_LEMMS articulation axis with the MIMI_LEMMS1 boresight at some articulated position. The Y-axis completes the right handed frame. This frame encapsulates the articulation characteristics of the MIMI_LEMMS instrument. To make use of it requires a C-kernel with coverage at the epochs of interest be loaded. The rotation matrix that takes vectors from the MIMI_LEMMS_ART frame to the MIMI_LEMMS_BASE frame follows: [ ] [ ] [ ROT ] = [ ANGLE ] [ ] [ ] Z where [x] represents the rotation matrix of a given angle x about i axis i, and ANGLE is the articulation angle. \begindata FRAME_CASSINI_MIMI_LEMMS_ART = -82764 FRAME_-82764_NAME = 'CASSINI_MIMI_LEMMS_ART' FRAME_-82764_CLASS = 3 FRAME_-82764_CLASS_ID = -82764 FRAME_-82764_CENTER = -82 CK_-82764_SCLK = -82 CK_-82764_SPK = -82 \begintext Magnetospheric Imaging Instrument Low Energy Magnetospheric Measurements 1 (MIMI_LEMMS1) The Z-axis of this frame is the instrument boresight. This frame requires one of two possible C-kernels: -- One kernel connects this instrument frame (-82762) directly to the spacecraft frame (-82000). -- The other possible kernel connects this instrument frame (-82762) to the articulation frame (-82764) defined above. The kernel that makes this connection for all epochs after launch is delivered with the kernel set. See the kernel comments for details of the frame construction. One should take care in the simultaneous loading of C-kernels that utilize different paths of the frame tree to connect CASSINI_MIMI_LEMMS1 to CASSINI_SC_COORD. See [1] for details regarding C-kernel precedence. \begindata FRAME_CASSINI_MIMI_LEMMS1 = -82762 FRAME_-82762_NAME = 'CASSINI_MIMI_LEMMS1' FRAME_-82762_CLASS = 3 FRAME_-82762_CLASS_ID = -82762 FRAME_-82762_CENTER = -82 CK_-82762_SCLK = -82 CK_-82762_SPK = -82 \begintext Magnetospheric Imaging Instrument Low Energy Magnetospheric Measurements 2 (MIMI_LEMMS2) The Z-axis of this frame is the instrument boresight. This frame requires one of two possible C-kernels: -- One kernel connects this instrument frame (-82763) directly to the spacecraft frame (-82000). -- The other possible kernel connects this instrument frame (-82763) to the articulation frame (-82764) defined above. The kernel that makes this connection for all epochs after launch is delivered with the kernel set. See the kernel comments for details of the frame construction. One should take care in the simultaneous loading of C-kernels that utilize different paths of the frame tree to connect CASSINI_MIMI_LEMMS2 to CASSINI_SC_COORD. See [1] for details regarding C-kernel precedence. \begindata FRAME_CASSINI_MIMI_LEMMS2 = -82763 FRAME_-82763_NAME = 'CASSINI_MIMI_LEMMS2' FRAME_-82763_CLASS = 3 FRAME_-82763_CLASS_ID = -82763 FRAME_-82763_CENTER = -82 CK_-82763_SCLK = -82 CK_-82763_SPK = -82 \begintext RADAR Frames ---------------------------------------------------------- Compiled from [23] and [5]: The RADAR instrument consists of 5 beams in the following configuration: ^ Xsc | | Ysc | <------o | Zsc | . . . Beam 1 Beam 2 Beam 3 Beam 4 Beam 5 | |-----x-----|-----x-----|----x----|-----x-----|-----x-----| | |-- 1.35 ---|-- 0.85 --|-- 0.85 --|-- 1.35 ---| | | V Beam 3 Direction The above figure illustrates the separation in degrees between the beam centers and their relation to the spacecraft frame. Note the angles in the frame definitions are specified fro the ``from instrument to (relative to) base frame'' transformation. RADAR Beam 1 (RADAR_1) RADAR Beam 1 is directed nominally 2.2 degrees off of the -Z axis of the spacecraft in the direction of the +Y axis of the spacecraft frame. The following definition encapsulates this frame: From [23]: [ ] [ ] [ ] [ ] [ ROT ] = [ 177.8 ] [ 0.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_RADAR_1 = -82810 FRAME_-82810_NAME = 'CASSINI_RADAR_1' FRAME_-82810_CLASS = 4 FRAME_-82810_CLASS_ID = -82810 FRAME_-82810_CENTER = -82 TKFRAME_-82810_SPEC = 'ANGLES' TKFRAME_-82810_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82810_ANGLES = ( 177.8, 0.0, 0.0 ) TKFRAME_-82810_AXES = ( 1, 2, 3 ) TKFRAME_-82810_UNITS = 'DEGREES' \begintext RADAR Beam 2 (RADAR_2) RADAR Beam 2 is directed nominally 0.85 degrees off of the -Z axis of the spacecraft in the direction of the +Y axis of the spacecraft frame. The following definition encapsulates this frame: From [23]: [ ] [ ] [ ] [ ] [ ROT ] = [ 179.15 ] [ 0.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: FRAME_CASSINI_RADAR_2 = -82811 FRAME_-82811_NAME = 'CASSINI_RADAR_2' FRAME_-82811_CLASS = 4 FRAME_-82811_CLASS_ID = -82811 FRAME_-82811_CENTER = -82 TKFRAME_-82811_SPEC = 'ANGLES' TKFRAME_-82811_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82811_ANGLES = ( 179.15, 0.0, 0.0 ) TKFRAME_-82811_AXES = ( 1, 2, 3 ) TKFRAME_-82811_UNITS = 'DEGREES' From [44], the RADAR Beam 2 reference frame is to be adjusted to the following: [ ] [ ] [ ] [ ] [ ROT ] = [ 179.15 ] [ -1.2 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_RADAR_2 = -82811 FRAME_-82811_NAME = 'CASSINI_RADAR_2' FRAME_-82811_CLASS = 4 FRAME_-82811_CLASS_ID = -82811 FRAME_-82811_CENTER = -82 TKFRAME_-82811_SPEC = 'ANGLES' TKFRAME_-82811_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82811_ANGLES = ( 179.15, -1.2, 0.0 ) TKFRAME_-82811_AXES = ( 1, 2, 3 ) TKFRAME_-82811_UNITS = 'DEGREES' \begintext RADAR Beam 3 (RADAR_3) RADAR Beam 3 is directed nominally along the -Z axis of the spacecraft frame. The following definition encapsulates this frame: From [23]: [ ] [ ] [ ] [ ] [ ROT ] = [ 180.0 ] [ 0.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_RADAR_3 = -82812 FRAME_-82812_NAME = 'CASSINI_RADAR_3' FRAME_-82812_CLASS = 4 FRAME_-82812_CLASS_ID = -82812 FRAME_-82812_CENTER = -82 TKFRAME_-82812_SPEC = 'ANGLES' TKFRAME_-82812_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82812_ANGLES = ( 180.0, 0.0, 0.0 ) TKFRAME_-82812_AXES = ( 1, 2, 3 ) TKFRAME_-82812_UNITS = 'DEGREES' \begintext RADAR Beam 4 (RADAR_4) RADAR Beam 4 is directed nominally 0.85 degrees off of the -Z axis of the spacecraft in the direction of the -Y axis of the spacecraft frame. The following definition encapsulates this frame: From [23]: [ ] [ ] [ ] [ ] [ ROT ] = [ 180.85 ] [ 0.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_RADAR_4 = -82813 FRAME_-82813_NAME = 'CASSINI_RADAR_4' FRAME_-82813_CLASS = 4 FRAME_-82813_CLASS_ID = -82813 FRAME_-82813_CENTER = -82 TKFRAME_-82813_SPEC = 'ANGLES' TKFRAME_-82813_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82813_ANGLES = ( 180.85, 0.0, 0.0 ) TKFRAME_-82813_AXES = ( 1, 2, 3 ) TKFRAME_-82813_UNITS = 'DEGREES' \begintext From [44], the RADAR Beam 4 reference frame is to be adjusted to the following: [ ] [ ] [ ] [ ] [ ROT ] = [ 180.85 ] [ -1.2 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. \begindata FRAME_CASSINI_RADAR_4 = -82813 FRAME_-82813_NAME = 'CASSINI_RADAR_4' FRAME_-82813_CLASS = 4 FRAME_-82813_CLASS_ID = -82813 FRAME_-82813_CENTER = -82 TKFRAME_-82813_SPEC = 'ANGLES' TKFRAME_-82813_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82813_ANGLES = ( 180.85, -1.2, 0.0 ) TKFRAME_-82813_AXES = ( 1, 2, 3 ) TKFRAME_-82813_UNITS = 'DEGREES' \begintext RADAR Beam 5 (RADAR_5) RADAR Beam 5 is directed nominally 2.2 degrees off of the -Z axis of the spacecraft in the direction of the -Y axis of the spacecraft frame. The following definition encapsulates this frame: From [23]: [ ] [ ] [ ] [ ] [ ROT ] = [ 182.2 ] [ 0.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_RADAR_5 = -82814 FRAME_-82814_NAME = 'CASSINI_RADAR_5' FRAME_-82814_CLASS = 4 FRAME_-82814_CLASS_ID = -82814 FRAME_-82814_CENTER = -82 TKFRAME_-82814_SPEC = 'ANGLES' TKFRAME_-82814_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82814_ANGLES = ( 182.2, 0.0, 0.0 ) TKFRAME_-82814_AXES = ( 1, 2, 3 ) TKFRAME_-82814_UNITS = 'DEGREES' \begintext RPWS Frames ---------------------------------------------------------- The RPWS antennae are located roughly on the +Y side of the Cassini orbiter, while the RPWS Langmuir Probe is roughly located on the -X side. Note the angles in the frame definitions are specified for the ``from instrument to (relative to) base frame'' transformation. Radio and Plasma Wave Science (RPWS) As [17] indicates, the ``collective'' RPWS boresight is nominally directed along the spacecraft +Y axis. Utilizing the Euler angles specified in this email, we obtain the following frame definition: From [17]: [ ] [ ] [ ] [ ] [ ROT ] = [ 180.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] X Y Z where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_RPWS = -82730 FRAME_-82730_NAME = 'CASSINI_RPWS' FRAME_-82730_CLASS = 4 FRAME_-82730_CLASS_ID = -82730 FRAME_-82730_CENTER = -82 TKFRAME_-82730_SPEC = 'ANGLES' TKFRAME_-82730_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82730_ANGLES = ( 180.0, -90.0, 0.0 ) TKFRAME_-82730_AXES = ( 3, 1, 3 ) TKFRAME_-82730_UNITS = 'DEGREES' \begintext Radio and Plasma Wave Science Electric Antenna System (RPWS_E[AXIS][SIGN]) From [24]: ``The RPWS electric antenna system is a triad of 10-meter conducting monopoles, symmetric about the Y-Z plane. Two of the elements are extended in a 120-degree "V" on either side of the magnetometer boom (i.e., the S/C Y-axis) and in a plane which is rotated up from the S/C X-Y plane containing the magnetometer boom by 37 degrees. These two elements are referred to as the EXPLUS and EXMINUS sensors. The third element is extended downward in the S/C Y-Z plane at an angleof 37 degrees from the S/C +Z axis. That said, it now should be explained that the "electrical" characteristics of these three antennas deviate from the physical alignment and lengths of the elements due to the complex ground plane provided by the spacecraft. It is these electrical characteristics that the three RPWS Frame definitions RPWS_EXPLUS, RPWS_EXMINUS, and RPWS_EZPLUS are intended to specify. Based upon model rheometry experiments, in which a model of the Cassini Spacecraft with fully extended RPWS antennas was immersed in a tank filled with an electrolytic, the following estimates have been made for the electrical axes of the three antenna elements: Frame Frame Z-Axis in CASSINI_SC_COORD "boresight" ------ -------------------------------- RPWS_EXPLUS [ 0.91202578, 0.27709462, -0.30236989 ] RPWS_EXMINUS [ -0.91202578, 0.27709462, -0.30236989 ] RPWS_EZPLUS [ -0.01091120, 0.52089537, 0.85355080 ] These numbers may change after the RPWS Jupiter Calibrations.'' Antenna Frame Definitions: From [14]: [ ] [ ] [ ] [ ] [ ROT ] = [ -16.9 ] [ -107.6 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_RPWS_EXPLUS = -82731 FRAME_-82731_NAME = 'CASSINI_RPWS_EXPLUS' FRAME_-82731_CLASS = 4 FRAME_-82731_CLASS_ID = -82731 FRAME_-82731_CENTER = -82 TKFRAME_-82731_SPEC = 'ANGLES' TKFRAME_-82731_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82731_ANGLES = ( -16.9, -107.6, 0.0 ) TKFRAME_-82731_AXES = ( 3, 2, 1 ) TKFRAME_-82731_UNITS = 'DEGREES' \begintext From [14]: [ ] [ ] [ ] [ ] [ ROT ] = [ -163.1 ] [ -107.6 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_RPWS_EXMINUS= -82732 FRAME_-82732_NAME = 'CASSINI_RPWS_EXMINUS' FRAME_-82732_CLASS = 4 FRAME_-82732_CLASS_ID = -82732 FRAME_-82732_CENTER = -82 TKFRAME_-82732_SPEC = 'ANGLES' TKFRAME_-82732_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82732_ANGLES = (-163.1, -107.6, 0.0 ) TKFRAME_-82732_AXES = ( 3, 2, 1 ) TKFRAME_-82732_UNITS = 'DEGREES' \begintext From [14]: [ ] [ ] [ ] [ ] [ ROT ] = [ -91.2 ] [ -31.4 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_RPWS_EZPLUS = -82733 FRAME_-82733_NAME = 'CASSINI_RPWS_EZPLUS' FRAME_-82733_CLASS = 4 FRAME_-82733_CLASS_ID = -82733 FRAME_-82733_CENTER = -82 TKFRAME_-82733_SPEC = 'ANGLES' TKFRAME_-82733_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82733_ANGLES = ( -91.2, -31.4, 0.0 ) TKFRAME_-82733_AXES = ( 3, 2, 1 ) TKFRAME_-82733_UNITS = 'DEGREES' \begintext Radio and Plasma Wave Science Langmuir Probe (RPWS_LP) From [24]: ``The RPWS Langmuir Probe is on the -X side of the spacecraft and can sense roughly the entire hemisphere defined by the RPWS_LP Frame.'' From [14]: [ ] [ ] [ ] [ ] [ ROT ] = [ 180.0 ] [ -90.0 ] [ 0.0 ] [ ] [ ] [ ] [ ] Z Y X where [x] represents the rotation matrix of a given angle x about i axis i. Nominal Frame Definition: \begindata FRAME_CASSINI_RPWS_LP = -82734 FRAME_-82734_NAME = 'CASSINI_RPWS_LP' FRAME_-82734_CLASS = 4 FRAME_-82734_CLASS_ID = -82734 FRAME_-82734_CENTER = -82 TKFRAME_-82734_SPEC = 'ANGLES' TKFRAME_-82734_RELATIVE = 'CASSINI_SC_COORD' TKFRAME_-82734_ANGLES = ( 180.0, -90.0, 0.0 ) TKFRAME_-82734_AXES = ( 3, 2, 1 ) TKFRAME_-82734_UNITS = 'DEGREES' \begintext