KPL/IK CIRS Instrument Kernel ============================================================================== This instrument kernel (I-kernel) contains references to the mounting alignment, internal and FOV geometry for the Cassini Composite Infrared Spectrometer (CIRS) instruments. 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 CIRS I-Kernel Version: \begindata TEXT_KERNEL_ID += 'CASSINI_CIRS V1.0.0 10-JULY-2019 IK' \begintext Version 1.0 -- July 10, 2019 -- Boris Semenov -- Updated CASSINI_CIRS_FP3 and CASSINI_CIRS_FP4 field of view sizes and related comments. See [9] for details. Version 0.9 -- June 11, 2002 -- Scott Turner -- Updated CASSINI_CIRS_FP3, CASSINI_CIRS_FP4, and CASSINI_CIRS_FPB field of view sizes. See [8] for details. Version 0.8 -- March 12, 2002 -- Scott Turner -- Added mode timing keywords for CASSINI_CIRS_FPB FOV definition. Version 0.7 -- January 23, 2002 -- Scott Turner -- Added CASSINI_CIRS_FPB FOV definition. -- Corrected CASSINI_CIRS_FP3 and CASSINI_CIRS_FP4 FOV definitions. These FOV angular extents were recorded as twice their actual value. Version 0.6 -- April 23, 2001 -- Scott Turner -- Updated kernel to utilize new FOV ANGLES specification. Version 0.5 -- August 15, 2000 -- Scott Turner -- Recalculated the FOV definitions to enhance precision. Version 0.4 -- June 12, 2000 -- Scott Turner -- Altered the FP1, FP3, and FP4 FOV definitions to conform to the 'CIRS Fields-of-View' PDF. Version 0.3 -- June 7, 2000 -- Scott Turner -- Changed the INS[#]_FOV_CENTER_PIXEL keyword to match the specification in the I-kernel SIS. Version 0.2 -- March 27, 2000 -- Scott Turner -- Altered the BOUNDARY_CORNERS vector definitions for the FP3 and FP4 FOV definitions since they were oriented incorrectly. -- Corrected a typo in the definition of FP1's FOV. -- Some cosmetic alterations to the layout of the kernel were made. -- Added TEXT_KERNEL_ID keyword. Version 0.1 -- March 17, 2000 -- Scott Turner -- This I-kernel reflects changes discussed at the SPICE meeting on 3/16/2000. -- All of the INS[ID]_SEQ_[WORD] keywords were eliminated. -- INS[ID]_SEQ_FOV_CENTER is now keyed to INS[ID]_FOV_CENTER_PIXEL. Version 0.0 -- March 6, 2000 -- Scott Turner -- Initial Prototype Release for Review. References ---------------------------------------------------------- 1. ``Cassini Science Instruments and Investigations'', Revised Second Printing. Stephen J. Edberg. 2. Cassini Spacecraft Frames Definition Kernel 3. JPL Cassini Project Web Page describing the instruments. 4. Cassini/NAIF SPICE Workship, November 8-9, 1999. 5. Email from Jeff Boyer regarding necessary data for footprint calculations. 6. 'CIRS Fields-of-View' PDF, Stephen J. Edberg. 7. Email from Jeff Boyer regarding missing CASSINI_CIRS_FPB mode timing keywords and their values. 8. Page 28 from ECR 100515 listing updated alignment information for CASSINI_CIRS detectors. 9. Email from Marcia Segura, UMD, ``Minor changes to the Cassini CIRS FOV definition.'', March 7, 2019 Contact Information ---------------------------------------------------------- Direct questions, comments or concerns about the contents of this kernel to: Scott Turner, NAIF/JPL, (818)-345-3157, sturner@spice.jpl.nasa.gov Implementation Notes ---------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this instrument 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 FURNSH and CSPICE routine furnsh_c load SPICE kernels as shown below: FORTRAN (SPICELIB) CALL FURNSH ( 'kernel_name' ) C (CSPICE) furnsh_c ( "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 details. This file was created and may be updated with a text editor or word processor. Naming Conventions ---------------------------------------------------------- All names referencing values in this I-kernel start with the characters `INS' followed by the NAIF Cassini spacecraft ID number (-82) followed by a NAIF three digit code for the CIRS instruments. (FP1 = 890, FP3 = 891, FP4 = 892, FPB = 893). The remainder of the name is an underscore character followed by the unique name of the data item. For example, the CIRS FP1 boresight direction in the CIRS FP1 optics frame (``CASSINI_CIRS_FP1'' -- see [2] ) is specified by: INS-82890_BORESIGHT The upper bound on the length of the name of any data item is 32 characters. If the same item is included in more than one file, or if the same item appears more than once within a single file, the latest value supersedes any earlier values. CIRS description ---------------------------------------------------------- From [3]: The Composite Infrared Spectrometer (CIRS) is designed to measure infrared energy of various wavelengths in the Saturnian system. It will address a wide variety of science objectives for the atmospheres of Saturn and Titan, and for Saturn's icy satellites and rings, including composition determination and thermal state measurements. The CIRS instrument consists of two assemblies: optics and electronics. For information on these components, see below. (CIRS) The CIRS optics assembly consists of a telescope, a far infrared interferometer, a mid infrared interferometer, a reference interferometer, a moving scan mechanism, a cooler, thermal control equipment, an optics assembly mount, covers for the telescope and cooler, and a calibration shutter mechanism. For information on these components, see below. (Optics Assembly) The telescope is composed of a 50.8 cm-diameter paraboloid primary mirror and a hyperboloid secondary mirror. A sun shade will be present around the primary mirror. This shade will also serve as the primary mirror radiator. A cylindrical tube extends from the central portion of the primary mirror to support the secondary mirror, which has its own radiator. The CIRS science data will be collected by two of the instrument's three interferometers. Interferometers are instruments designed to make precise measurements of wavelength within some range of the electromagnetic spectrum. For example, the CIRS far infrared (FIR) interferometer covers a spectral range of 10-600 cm-1. The FIR instrument is a polarizing interferometer that uses substrate-mounted wire grid polarizers to polarize and analyze the radiation. The interferometer operates by first polarizing the radiation and then modulating its polarization. The FIR interferometer has its moving mirror mounted on one end of the moving scan mechanism, which it shares with the mid infrared interferometer. The fixed and moving mirrors are roof mirrors, and the FIR focal plane consists of a matched pair of thermopile detectors, each with a concentrator. The mid-infrared (MIR) interferometer, which is a conventional Michelson instrument, covers a spectral range of 600-1500 1/cm. The MIR interferometer has its moving mirror mounted on the opposite end of the moving scan mechanism from the FIR mirror. The fixed and moving mirrors are cube corners, and the MIR uses a germanium lens to focus the interferometer output onto focal planes FP3 and FP4. The reference interferometer will provide timing correlation of the science data sampling to the scan mechanism position. Specifically, the scan mechanism's motion will produce a variable reference interferometer signal that will be used to generate the timing signals necessary to time the recording of science data. The reference interferometer is a Michelson instrument, used on-axis at the optic center of the MIR interferometer. It includes laser diode and LED sources, a quartz beamsplitter/compensator, optics, and a silicon detector. The reference interferometer uses cube corners for the fixed and moving mirrors. The moving scan mechanism subassembly includes the optical and mechanical components in the optics assembly required for moving the interferometer mirrors to permit controlled sampling in the optical path difference. This subassembly consists of a common carriage with a moving shaft for the three interferometer mirrors, a motor to drive the shaft, a cantilever-spring motor mount, and a velocity transducer. The scan mechanism includes a launch lock that can be locked and unlocked repeatedly without refurbishment by remote command through the onboard computer. A single-stage, passive cooler, radiating to space, provides a 70-80 K cold finger with four discrete, commandable set points within that range. The nominal set point temperature will be 80 K. The cold finger has heaters for decontamination and detector annealing. A system of thermal control equipment, including temperature sensors, electrical heaters, proportional heater controllers, and radiators, is used to maintain the thermal control of the optics assembly. The temperature of the instrument is monitored by sensors located at appropriate places in the instrument, including, but not limited to, the telescope mirrors, the interferometers, the detectors, the optics housing, the radiating surface, and the Michelson motor. The optics assembly mount thermally decouples the optics assembly from the remote sensing pallet (RSP). The telescope and 80-K cooler will be protected with covers until the orbiter leaves the inner solar system, at which point the covers will be separately jettisoned by wax thermal actuators (WTAs). Each cover has two redundant parrafin actuators, either one of which can initiate the action of a pin-puller assembly, which in turn initiates the action of an ejection spring assembly. The calibration shutter mechanism will be used to interrupt the MIR beam, causing the MIR detectors to view a controlled 170-K black surface inside the instrument. The shutter is commandable through the onboard computer. The CIRS electronics assembly includes front-end electronics, scan mechanism electronics, reference interferometer electronics, temperature control and monitor electronics, the instrument data system, and power converter electronics for conditioning the spacecraft power as required by the instrument. For information on these components, see below. (Electronics Assembly) The front-end electronics provides analog and digital processing of the detector signals. This includes filtering, multiplexing, amplification, and digitization to achieve the science data requirements. The scan mechanism electronics provides the operation and control of the linear moving scan mechanism. The control system provides a constant velocity travel during the forward (scan) direction and a fast flyback during the reverse (flyback) direction. The control is a function of the reference interferometer timing signals and other sensors, as needed. The scan mechanism electronics also includes circuitry to actuate the calibration shutter. The reference interferometer electronics provides timing signals for accurate sampling of the science data and for accurate control of the scan mechanism velocity. The CIRS instrument has four zones that are independently controlled by the temperature control and monitor electronics. These zones are the primary mirrors, the secondary mirrors, the interfermeters, and the 80-K cooler. The temperature is monitored by temperature sensors located on the four zones, which provide accurate temperature values at the cooled temperatures. The sensors located on the optics assembly provide course values at the decontamination temperature. The monitored temperatures will be transmitted to the spacecraft. The instrument data system (IDS) is a microprocessor circuit that provides the instrument data processing function and communication with the spacecraft. The IDS receives and processes commands, data, and timing information from the spacecraft and configures and controls the instrument's operational states. It processes the science data from the front-end electronics and the housekeeping data from all of the subassemblies, and then it transmits these data to the spacecraft. The power converter electronics (PCE) conditions the regulated power received from the spacecraft and provides direct power to the instrument data system and the temperature controller and monitor subassemblies. The PCE also provides, on command, power to other subassemblies and release of the scan mechanism launch lock, the 80-K cooler cover, and the telescope cover. CIRS Field of View Parameters ---------------------------------------------------------- FOV Sizes (in degrees) Spacecraft Frame: Zsc ^ | | <-----o Xsc Ysc Ybs ___ ^ | ************* | | **** **** | | *** *** __ ..... __ ___ | ** ** | | | | | | * * | | | | | | * * | | | | | | * * | | | | | | * * | | | | | | * * | | | | | 0.22 * x * <-- | | x | | 0.17 | * * Xbs | | Zbs| | | | * * | | | | | | * * | | | | | | * * | | | | | | * * | | | | | | ** ** |__|.....|__| _|_ | *** *** FP4 FP3 | **** **** _|_ ************* |--| |--| FP1 0.02 0.02 The field of view parameters for the three focal planes that constitute the CIRS detectors are: -- Focal Plane 1 (FP1) -- Focal Plane 3 (FP3) -- Focal Plane 4 (FP4) -- Focal Plane Boresight (FPB) Circular FOVs: ------------ ------------------- Detector Diameter ------------ ------------------- FP1 0.223 degrees ------------ ------------------- Rectangular FOVs: ------------ -------------------- -------------------- Detector Horizontal Vertical ------------ -------------------- -------------------- FP3 0.0169 degrees 0.169 degrees FP4 0.0169 degrees 0.169 degrees FPB 0.0688 degrees 0.172 degrees ------------ -------------------- -------------------- The keywords INS[ID]_FOV_FRAME, INS[ID]_FOV_SHAPE, INS[ID]_BORESIGHT, and the FOV ANGLES specification keywords defined below are used to describe the instrument field of view. Since FP1 is a circular field of view and FP3 and FP4 are rectangular, the INS[ID]_FOV_SHAPE will either be 'CIRCLE' or 'RECTANGLE'. In the case of FP1, GETFOV returns a single vector that lies along the edge of the circular cone, and for FP3, FP4, and FPB four vectors. All four FOV boresights lie along the Z-axis. Focal Plane #1 (FP1) FOV Definition The FP1 FOV is defined with respect to the CASSINI_CIRS_FP1 frame as a cone with a 0.112 degree (0.00195 radian) half-extent, centered on the +Z axis of the frame. \begindata INS-82890_FOV_FRAME = 'CASSINI_CIRS_FP1' INS-82890_FOV_SHAPE = 'CIRCLE' INS-82890_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82890_FOV_CLASS_SPEC = 'ANGLES' INS-82890_FOV_REF_VECTOR = ( +1.0000000000000000 0.0000000000000000 0.0000000000000000 ) INS-82890_FOV_REF_ANGLE = ( 0.00195 ) INS-82890_FOV_ANGLE_UNITS = 'RADIANS' \begintext Focal Plane #3 (FP3) FOV Definition The FP3 FOV is defined with respect to the CASSINI_CIRS_FP3 frame as a rectangle with a 0.0845 degrees (0.001475 radian) half-extent in the YZ plane and a 0.00845 degree (0.0001475 radian) half-extent in the XZ plane, centered on the +Z axis of the frame. \begindata INS-82891_FOV_FRAME = 'CASSINI_CIRS_FP3' INS-82891_FOV_SHAPE = 'RECTANGLE' INS-82891_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82891_FOV_CLASS_SPEC = 'ANGLES' INS-82891_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82891_FOV_REF_ANGLE = ( 0.0014750 ) INS-82891_FOV_CROSS_ANGLE = ( 0.0001475 ) INS-82891_FOV_ANGLE_UNITS = 'RADIANS' \begintext Focal Plane #4 (FP4) FOV Definition The FP4 FOV is defined with respect to the CASSINI_CIRS_FP4 frame as a rectangle with a 0.0845 degrees (0.001475 radian) half-extent in the YZ plane and a 0.00845 degree (0.0001475 radian) half-extent in the XZ plane, centered on the +Z axis of the frame. \begindata INS-82892_FOV_FRAME = 'CASSINI_CIRS_FP4' INS-82892_FOV_SHAPE = 'RECTANGLE' INS-82892_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82892_FOV_CLASS_SPEC = 'ANGLES' INS-82892_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82892_FOV_REF_ANGLE = ( 0.0014750 ) INS-82892_FOV_CROSS_ANGLE = ( 0.0001475 ) INS-82892_FOV_ANGLE_UNITS = 'RADIANS' \begintext CIRS Focal Plane Boresight: This FOV definition was created to assist software developers in utilizing the CASSINI_CIRS_FPB frame to point the orbiter. By definition it is a rectangular FOV that encloses CASSINI_CIRS_FP3 and CASSINI_CIRS_FP4. From [8], we have that the FP3 and FP4 boresights are separated by 0.94 milliradians, and each detector is 0.3 milliradians square. Thus: \begindata INS-82893_FOV_FRAME = 'CASSINI_CIRS_FPB' INS-82893_FOV_SHAPE = 'RECTANGLE' INS-82893_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82893_FOV_CLASS_SPEC = 'ANGLES' INS-82893_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82893_FOV_REF_ANGLE = ( 0.0015000 ) INS-82893_FOV_CROSS_ANGLE = ( 0.0006200 ) INS-82893_FOV_ANGLE_UNITS = 'RADIANS' \begintext CIRS Radiator (RAD): The FOV values for the CIRS radiator are place holders until a time when the real values are provided. \begindata INS-82898_FOV_FRAME = 'CASSINI_CIRS_RAD' INS-82898_FOV_SHAPE = 'CIRCLE' INS-82898_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82898_FOV_CLASS_SPEC = 'ANGLES' INS-82898_FOV_REF_VECTOR = ( +1.0000000000000000 0.0000000000000000 0.0000000000000000 ) INS-82898_FOV_REF_ANGLE = ( 90.0 ) INS-82898_FOV_ANGLE_UNITS = 'DEGREES' \begintext CIRS Pixel Parameters ---------------------------------------------------------- These parameters describe the pixel structure associated with the instruments and their fields of views. In some cases this is a generalization of the notion of pixel, in that instead of representing pixels on a CCD they may represent a collection of individual detectors. Focal Plane 1 (FP1) \begindata INS-82890_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82890_PIXEL_SAMPLES = ( 1 ) INS-82890_PIXEL_LINES = ( 1 ) \begintext Focal Plane 3 (FP3) \begindata INS-82891_FOV_CENTER_PIXEL = ( 4.5, 0 ) INS-82891_PIXEL_SAMPLES = ( 1 ) INS-82891_PIXEL_LINES = ( 10 ) \begintext Focal Plane 4 (FP4) \begindata INS-82892_FOV_CENTER_PIXEL = ( 4.5, 0 ) INS-82892_PIXEL_SAMPLES = ( 1 ) INS-82892_PIXEL_LINES = ( 10 ) \begintext Focal Plane Boresight (FPB) \begindata INS-82893_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82893_PIXEL_SAMPLES = ( 1 ) INS-82893_PIXEL_LINES = ( 1 ) \begintext CIRS Radiator (RAD) \begindata INS-82898_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82898_PIXEL_SAMPLES = ( 1 ) INS-82898_PIXEL_LINES = ( 1 ) \begintext Instrument Mode Timing ---------------------------------------------------------- The following values were provided as samples in [5]. The values are defined in [5] as follows: ``The initial values for the following keywords are given per instrument number: INS[instrument number]_[instrument acronym]_MODE_NAME INS[instrument number]_[instrument acronym]_TRIGGER_OFFSET INS[instrument number]_[instrument acronym]_CYCLE_DURATION INS..._MODE_NAME contains the name of the instrument mode for the INS..._TRIGGER_OFFSET and INS..._CYCLE_DURATION keywords. INS..._TRIGGER_OFFSET specifies the reference time of the first instrument frame (to be calculated for a footprint) relative to the time of transacting the corresponding TRIGGER command. The units are SFOC duration. INS..._CYCLE_DURATION specifies the duration between successive instrument frames (from the first one) for the INS..._MODE_NAME.'' FP1 Mode Timing The following values define the instrument modes and timing for the CIRS FP1. \begindata INS-82890_MODE_NAME = 'ONE' INS-82890_TRIGGER_OFFSET = '0:01:00.0' INS-82890_CYCLE_DURATION = '0:00:52.5' \begintext FP3 Mode Timing The following values define the instrument modes and timing for the CIRS FP3. \begindata INS-82891_MODE_NAME = 'ONE_ORIGINAL' INS-82891_TRIGGER_OFFSET = '0:01:00.0' INS-82891_CYCLE_DURATION = '0:00:52.5' \begintext FP4 Mode Timing The following values define the instrument modes and timing for the CIRS FP4. \begindata INS-82892_MODE_NAME = 'ONE_ORIGINAL' INS-82892_TRIGGER_OFFSET = '0:01:00.0' INS-82892_CYCLE_DURATION = '0:00:52.5' \begintext FPB Mode Timing The following values define the instrument modes and timing for the CIRS FPB. \begindata INS-82893_MODE_NAME = 'ONE_ORIGINAL' INS-82893_TRIGGER_OFFSET = '0:01:00.0' INS-82893_CYCLE_DURATION = '0:00:52.5' \begintext NAIF ID Code to Name Mapping ---------------------------------------------------------- The following keywords define names for the corresponding ID Codes. See [4] for details. \begindata NAIF_BODY_NAME += ( 'CASSINI_CIRS_FP1' ) NAIF_BODY_CODE += ( -82890 ) NAIF_BODY_NAME += ( 'CASSINI_CIRS_FP3' ) NAIF_BODY_CODE += ( -82891 ) NAIF_BODY_NAME += ( 'CASSINI_CIRS_FP4' ) NAIF_BODY_CODE += ( -82892 ) NAIF_BODY_NAME += ( 'CASSINI_CIRS_FPB' ) NAIF_BODY_CODE += ( -82893 ) NAIF_BODY_NAME += ( 'CASSINI_CIRS_RAD' ) NAIF_BODY_CODE += ( -82898 ) \begintext Platform ID ---------------------------------------------------------- The CIRS instrument is mounted on the Remote Sensing Palette, which is connected to the Cassini Spacecraft body. Therefore the value in the keywords below are -82000. \begindata INS-82890_PLATFORM_ID = ( -82000 ) INS-82891_PLATFORM_ID = ( -82000 ) INS-82892_PLATFORM_ID = ( -82000 ) INS-82893_PLATFORM_ID = ( -82000 ) INS-82898_PLATFORM_ID = ( -82000 ) \begintext