KPL/FK \beginlabel PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM RECORD_BYTES = "N/A" ^SPICE_KERNEL = "mgs_v10.tf" MISSION_NAME = "MARS GLOBAL SURVEYOR" SPACECRAFT_NAME = "MARS GLOBAL SURVEYOR" DATA_SET_ID = "MGS-M-SPICE-6-V1.0" KERNEL_TYPE_ID = FK PRODUCT_ID = "mgs_v10.tf" PRODUCT_CREATION_TIME = 2007-02-21T16:31:31 PRODUCER_ID = "NAIF/JPL" MISSION_PHASE_NAME = "N/A" PRODUCT_VERSION_TYPE = ACTUAL PLATFORM_OR_MOUNTING_NAME = "N/A" START_TIME = "N/A" STOP_TIME = "N/A" SPACECRAFT_CLOCK_START_COUNT = "N/A" SPACECRAFT_CLOCK_STOP_COUNT = "N/A" TARGET_NAME = MARS INSTRUMENT_NAME = "N/A" NAIF_INSTRUMENT_ID = "N/A" SOURCE_PRODUCT_ID = "N/A" NOTE = "See comments in the file for details" OBJECT = SPICE_KERNEL INTERCHANGE_FORMAT = ASCII KERNEL_TYPE = FRAMES DESCRIPTION = "MGS Frames Kernel contains the complete set of frame definitions for the spacecraft, its structures, and science instruments. " END_OBJECT = SPICE_KERNEL \endlabel Mars Global Surveyor Frame Definitions Kernel =============================================================================== This Frames Kernel (FK) file contains the complete set of frame definitions for the Mars Global Surveyor (MGS) spacecraft, its structures, and science instruments. This frames kernel also contains name - to - NAIF ID mappings for the MGS science instruments and s/c structures (see the last section of the file.) Version and Date ------------------------------------------------------------------------------- Version 1.0 -- January 16, 2007 Initial release. This release incorporates all frame definitions that for a number of historical reasons were initially placed into the following MGS text kernels: -- SCLK (contained the definitions of the spacecraft and solar array frames) -- MAG/ER IK (contained the definitions of the additional solar array frames and MAG and ER sensor frames) -- MHSA IK (contained the MHSA frames definitions) -- MOC IK (contained the MOC frames definitions) -- MOLA IK (contained the MOLA frame definition) -- TES IK (contained the TES frame definition) -- HGA FK (contained the definitions of the HGA and other antenna frames) Note that although the frame definitions were copied to this FK file, they were NOT removed from the text kernels in which they were originally located. References ------------------------------------------------------------------------------- 1. ``Frames Required Reading'' 2. ``Kernel Pool Required Reading'' 3. ``C-Kernel Required Reading'' 4. The latest MGS SCLK file (mgs_sclkscet_00061.tsc as of 01/16/07) 5. The latest MAG/ER IK file (mgs_mager_v12.ti as of 01/16/07) 6. The latest MHSA IK file (mgs_mhsa_v23.ti as of 01/16/07) 7. The latest MOC IK file (mgs_moc_v20.ti as of 01/16/07) 8. The latest MOLA IK file (mgs_mola_v26.ti as of 01/16/07) 9. The latest TES IK file (mgs_tes_v12.ti as of 01/16/07) 10. The latest HGA FK file (mgs_hga_v10.tf as of 01/16/07) Contact Information ------------------------------------------------------------------------------- Boris V. Semenov, NAIF/JPL, (818)-354-8136, Boris.Semenov@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 (see [2]). The SPICELIB routine FURNSH (furnsh_c in CSPICE, cspice_furnsh in ICY) loads a kernel file into the pool as follows: CALL FURNSH ( 'frame_kernel_name' ) furnsh_c ( "frame_kernel_name" ); cspice_furnsh, "frame_kernel_name" This file was created and may be updated with a text editor or word processor. Should you need to update this kernel in any way, please, modify the "Version and Date" section above to reflect the changes. MGS Frames ------------------------------------------------------------------------------- The following MGS frames are defined in this kernel file: Frame Name "Relative to" Frame Frame Type Frame ID ====================== ===================== ============ ======== Spacecraft frame: ----------------- MGS_SPACECRAFT J2000 CK -94000 Antenna frames: --------------- MGS_HGA_HINGE MGS_SPACECRAFT CK -94070 MGS_HGA_EL_GIMBAL MGS_HGA_HINGE CK -94071 MGS_HGA_AZ_GIMBAL MGS_HGA_EL_GIMBAL CK -94072 MGS_HGA MGS_HGA_AZ_GIMBAL FIXED -94073 MGS_LGT1 MGS_HGA FIXED -94074 MGS_LGT2 MGS_HGA FIXED -94075 MGS_LGR1 MGS_SPACECRAFT FIXED -94076 MGS_LGR2 MGS_SPACECRAFT FIXED -94077 Solar Array frames: ------------------- MGS_LEFT_SOLAR_ARRAY MGS_SPACECRAFT CK -94001 MGS_RIGHT_SOLAR_ARRAY MGS_SPACECRAFT CK -94002 MGS_+Y_SOLAR_ARRAY MGS_LEFT_SOLAR_ARRAY FIXED -94901 MGS_-Y_SOLAR_ARRAY MGS_RIGHT_SOLAR_ARRAY CK -94902 Science Instrument frames: -------------------------- MGS_TES MGS_SPACECRAFT FIXED -94010 MGS_MHSA MGS_SPACECRAFT FIXED -94020 MGS_MHSA_D1 MGS_MHSA FIXED -94021 MGS_MHSA_D2 MGS_MHSA FIXED -94022 MGS_MHSA_D3 MGS_MHSA FIXED -94023 MGS_MHSA_D4 MGS_MHSA FIXED -94024 MGS_MOC_NA MGS_SPACECRAFT FIXED -94031 MGS_MOC_WA_RED MGS_SPACECRAFT FIXED -94032 MGS_MOC_WA_BLUE MGS_SPACECRAFT FIXED -94033 MGS_MOLA MGS_SPACECRAFT FIXED -94040 MGS_MAG_+Y_SENSOR MGS_+Y_SOLAR_ARRAY FIXED -94051 MGS_MAG_-Y_SENSOR MGS_-Y_SOLAR_ARRAY FIXED -94052 MGS_ER MGS_SPACECRAFT FIXED -94053 MGS Frames Hierarchy ------------------------------------------------------------------------------- The diagram below shows the MGS reference frames hierarchy: "J2000" +-----------------------------------------------+ | | | | <--pck | | <--pck V | V "IAU_MARS" | "IAU_EARTH" ---------- | ----------- | | | | "MGS_MOC_WA_BLUE" | ----------------- | ^ | | | | <--fixed | | "MGS_MHSA_D#" | "MGS_MOC_WA_RED" | ------------- | ---------------- | ^ | ^ | | | | | fixed--> | | | <-fxd | | | | | "MGS_MHSA" "MGS_MOLA" | "MGS_MOC_NA" | | ---------- ---------- | ------------ | | ^ ^ | | | | | | | | | | | fxd-> | ck--> | | <-fxd | | | | | | | | | | V | | | | | "MGS_SPACECRAFT" | | | +-----------------------------------------------+ | | | | | | | | fxd-> | fxd-> | | | <-fxd | <-fxd | | | | | | | | | V V | V V | | "MGS_LGR1" "MGS_ER" | "MGS_TES" "MGS_LGR2" | | ---------- -------- | --------- ---------- | | | | | <--ck | <--ck | <--ck | | | V V V "MGS_RIGHT_SOLAR_ARRAY" "MGS_HGA_HINGE" "MGS_LEFT_SOLAR_ARRAY" ----------------------- --------------- ---------------------- | | | | <--ck | <--ck | <--fixed | | | V | V "MGS_-Y_SOLAR_ARRAY" "MGS_HGA_EL_GIMBAL" "MGS_+Y_SOLAR_ARRAY" -------------------- ------------------- -------------------- | | | | <--fixed | <--ck | <--fixed | | | V V V "MGS_MAG_-Y_SENSOR" "MGS_HGA_AZ_GIMBAL" "MGS_MAG_+Y_SENSOR" ------------------- ------------------- ------------------- | | <--fixed | V "MGS_HGA" +-----------------------------------------------+ | | | <--fixed | <--fixed | | V V "MGS_LGT1" "MGS_LGT2" ---------- ---------- Spacecraft Frame ------------------------------------------------------------------------------- This section contains the definition of the spacecraft reference frame. This definition was copied to this FK file from the latest MGS SCLK file where it resided during mission operations (for historical reasons). The spacecraft frame is defined by the s/c design as follows: - +Z axis is parallel to the nominal science instrument boresights; - +X axis is parallel to the nominal HGA boresight for the antenna in the stowed position; - +Y axis completes the right hand frame; - the origin of the frame is centered on the launch vehicle separation plane. This diagrams illustrates the s/c frame: Scince Deck ._________________. ._______. ._________________. | \ |HGA Side / | | o| |o | | / | ^+Zsc \ | ._________________. .___|___. ._________________. | | | /__|__\ +Xsc is /_o------> +Ysc out of the page +Xsc Since the S/C bus attitude with respect to an inertial frame is provided by a C kernel (see [3]), this frame is defined as a CK-based frame. \begindata FRAME_MGS_SPACECRAFT = -94000 FRAME_-94000_NAME = 'MGS_SPACECRAFT' FRAME_-94000_CLASS = 3 FRAME_-94000_CLASS_ID = -94000 FRAME_-94000_CENTER = -94 CK_-94000_SCLK = -94 CK_-94000_SPK = -94 \begintext TES Frames ------------------------------------------------------------------------------- This section contains the definition of the reference frame for the Thermal Emission Spectrometer (TES). The description and frame definition provided in this section were copied from the TES IK file ([9]). In the process, only the description was modified; the definition was copied ``as is.'' TES Frames Summary ------------------ The following TES frame is defined in this kernel file: Frame Name "Relative to" Frame Frame Type Frame ID ====================== ===================== ============ ======== MGS_TES MGS_SPACECRAFT FIXED -94010 TES Frames Hierarchy -------------------- The diagram below shows the TES frames hierarchy: "J2000" +-----------------------------------------------+ | | | | <--pck | | <--pck V | V "IAU_MARS" | "IAU_EARTH" ---------- | ----------- | | <--ck | V "MGS_SPACECRAFT" ---------------- | | <--fixed | V "MGS_TES" --------- TES Alignment ------------- The offset of the TES instrument fixed frame relative to the Mars Global Surveyor spacecraft frame can be specified as three rotation angles -- ROLL, PITCH and YAW. From these angles a rotation matrix can be constructed that will transform the components of a vector expressed in the spacecraft frame to components expressed in the TES instrument fixed frame. For example, if x y and z are the components of a vector expressed in the spacecraft frame, X Y and Z will be the components of the same vector expressed in the TES instrument fixed frame: [ X ] [ ] [ x ] | Y | = | ROT | | y | [ Z ] [ ] [ z ] where ROT is the rotation matrix constructed from the rotation angles as follows: [ ] [ ] [ ] [ ] [ ROT ] = [ YAW ] [ PITCH ] [ ROLL ] [ ] [ ] [ ] [ ] Z Y X where each of three matrices on the right side represent a coordinate frame rotation by the given angle around the indicated axis. The following values of ROLL, PITCH and YAW were measured during the pre-launch alignment calibration: ROLL = 0.016 (degrees) PITCH = 0.014 (degrees) YAW = 359.996 (degrees) TES Frame Definition -------------------- The TES instrument frame, MGS_TES, is defined as follows: - +Z axis is the instrument boresight; nominally co-aligned with the s/c +Z axis; - +Y axis nominally points in the same direction as the s/c +Y axis; - +X axis completes the right hand frame; nominally points in the same direction as the s/c +X axis; This picture illustrates the MGS_TES frame: ^+Ztes | | +Xtes | +Ytes o------> ._________________. .__|_|__. ._________________. | \ | | / | | o| |o | | / | ^+Zsc \ | ._________________. .___|___. ._________________. | | | /__|__\ +Xsc and +Xtes /_o------> +Ysc are out of the page +Xsc The block below provides the frame definition keyword set for the TES frame incorporating the rotation angles specified in the previous subsection (note the opposite sign/order of rotations in the definition because the definition contains the transformation from the instrument frame to the spacecraft frame, see [1]): \begindata FRAME_MGS_TES = -94010 FRAME_-94010_NAME = 'MGS_TES' FRAME_-94010_CLASS = 4 FRAME_-94010_CLASS_ID = -94010 FRAME_-94010_CENTER = -94 TKFRAME_-94010_SPEC = 'ANGLES' TKFRAME_-94010_RELATIVE = 'MGS_SPACECRAFT' TKFRAME_-94010_ANGLES = ( -0.000279252680, -0.000244346095, -6.283115494010 ) TKFRAME_-94010_AXES = ( 1, 2, 3 ) TKFRAME_-94010_UNITS = 'RADIANS' \begintext MOLA Frames ------------------------------------------------------------------------------- This section contains the definition of the reference frame for the Mars Orbiter Laser Altimeter (MOLA). The description and frame definition provided in this section were copied from the MOLA IK file ([8]). In the process, only the description was modified; the definition was copied ``as is.'' MOLA Frames Summary ------------------- The following MOLA frame is defined in this kernel file: Frame Name "Relative to" Frame Frame Type Frame ID ====================== ===================== ============ ======== MGS_MOLA MGS_SPACECRAFT FIXED -94040 MOLA Frames Hierarchy --------------------- The diagram below shows the MOLA frames hierarchy: "J2000" +-----------------------------------------------+ | | | | <--pck | | <--pck V | V "IAU_MARS" | "IAU_EARTH" ---------- | ----------- | | <--ck | V "MGS_SPACECRAFT" ---------------- | | <--fixed | V "MGS_MOLA" ---------- MOLA Alignment -------------- The offset of the MOLA instrument fixed frame relative to the Mars Global Surveyor spacecraft frame can be specified as three rotation angles -- ROLL, PITCH and YAW. From these angels a rotation matrix can be constructed that will transform the components of a vector expressed in the spacecraft frame to components expressed in the MOLA instrument fixed frame. For example, if x y and z are the components of a vector expressed in the spacecraft frame, X Y and Z will be the components of the same vector expressed in the MOLA instrument fixed frame: [ X ] [ ] [ x ] | Y | = | ROT | | y | [ Z ] [ ] [ z ] where ROT is the rotation matrix constructed from the rotation angles as follows: [ ] [ ] [ ] [ ] [ ROT ] = [ YAW ] [ PITCH ] [ ROLL ] [ ] [ ] [ ] [ ] Z Y X where each of three matrices on the right side represent a coordinate frame rotation by the given angle around the indicated axis. This set of MOLA alignment angles was derived by the MOLA team from in-flight calibration data: ROLL = -0.0029 (degrees) PITCH = 359.9914 (degrees) YAW = 0.059 (degrees) MOLA Frame Definition --------------------- The MOLA instrument frame, MGS_MOLA, is defined as follows: - +Z axis is the receiver boresight; nominally co-aligned with the s/c +Z axis; - +Y axis nominally points in the same direction as the s/c +Y axis; - +X axis completes the right hand frame; nominally points in the same direction as the s/c +X axis; This picture illustrates the MGS_MOLA frame: ^+Zmola | | +Xmola.|_. +Ymola \ o------> ._________________. .____\_/. ._________________. | \ | | / | | o| |o | | / | ^+Zsc \ | ._________________. .___|___. ._________________. | | | /__|__\ +Xsc and +Xmola /_o------> +Ysc are out of the page +Xsc The block below provides the frame definition keyword set for the MOLA frame incorporating the rotation angles specified in the previous subsection (note the opposite sign/order of rotations in the definition because the definition contains the transformation from the instrument frame to the spacecraft frame, see [1]): \begindata FRAME_MGS_MOLA = -94040 FRAME_-94040_NAME = 'MGS_MOLA' FRAME_-94040_CLASS = 4 FRAME_-94040_CLASS_ID = -94040 FRAME_-94040_CENTER = -94 TKFRAME_-94040_SPEC = 'ANGLES' TKFRAME_-94040_RELATIVE = 'MGS_SPACECRAFT' TKFRAME_-94040_ANGLES = ( 0.0000506145, -6.283035209, -0.001029744259 ) TKFRAME_-94040_AXES = ( 1, 2, 3 ) TKFRAME_-94040_UNITS = 'RADIANS' \begintext MOC Frames ------------------------------------------------------------------------------- This section contains the definitions of the reference frames for the Mars Orbiter Camera camera (MOC). The description and frame definitions provided in this section were copied from the MOC IK file ([7]). In the process, only the description was modified; the definitions were copied ``as is.'' MOC Frames Summary ------------------ The following MOC frames are defined in this kernel file: Frame Name "Relative to" Frame Frame Type Frame ID ====================== ===================== ============ ======== MGS_MOC_NA MGS_SPACECRAFT FIXED -94031 MGS_MOC_WA_RED MGS_SPACECRAFT FIXED -94032 MGS_MOC_WA_BLUE MGS_SPACECRAFT FIXED -94033 MOC Frames Hierarchy -------------------- The diagram below shows the MOC frames hierarchy: "J2000" +-----------------------------------------------+ | | | | <--pck | | <--pck V | V "IAU_MARS" | "IAU_EARTH" ---------- | ----------- | | <--ck | V "MGS_SPACECRAFT" +-----------------------------------------------+ | | | | <--fixed | <--fixed | <--fixed | | | V V V "MGS_MOC_NA" "MGS_MOC_WA_RED" "MGS_MOC_WA_BLUE" ------------ ---------------- ----------------- MOC Camera Alignments --------------------- The offset of each individual MOC camera frame relative to the Mars Global Surveyor spacecraft frame can be specified as three rotation angles -- ROLL, PITCH and YAW. From these angles a rotation matrix can be constructed that will transform the components of a vector expressed in the spacecraft frame to components expressed in the MOC camera fixed frame. For example, if x y and z are the components of a vector expressed in the spacecraft frame, X Y and Z will be the components of the same vector expressed in the MOC camera frame: [ X ] [ ] [ x ] | Y | = | ROT | | y | [ Z ] [ ] [ z ] where ROT is the rotation matrix constructed from the rotation angles as follows: [ ] [ ] [ ] [ ] [ ROT ] = [ YAW ] [ PITCH ] [ ROLL ] [ ] [ ] [ ] [ ] Z Y X where each of three matrices on the right side represent a coordinate frame rotation by the given angle around the indicated axis. This set of MOC camera alignment angles was derived by USGS as the result of extensive analysis of the in-flight MOC images: ---------------------------------------------------------------- Instrument Roll, deg Pitch, deg Yaw, deg ---------------------------------------------------------------- MOC-NA 0.11463 -0.07162 0.18000 MOC-WA/RED (*) 1.04764 -0.45229 -0.78644 MOC-WA/BLUE (*) 1.01022 -0.35472 -0.30189 (*) The boresight direction defined by these angles for the WA/RED and WA/BLUE cameras corresponds to the pixel closest to the optical axis rather than to the central pixel of the line detector. For the WA/RED camera it's pixel 1673.65; for the WA/BLUE camera it's pixel 1687.58. For both WA cameras these angles define the frame with respect to which the radial distortion function provided in the MOC IK file ([7]). MOC Frames Definitions ---------------------- The NA camera frame is defined as follows: - +Z axis is the camera boresight, looking outwards (based on the view direction from the detector line central pixel); - +Y axis is along the camera detector line and points in the same direction as the s/c +Y axis; - +X axis completes the right hand frame (X cross Y = Z); The WA camera frames are defined as follows: - +Z axis is the camera optical boresight, looking outwards (based on the view direction from the pixel closest to the optical axis of the camera -- pixel 1673.6 for WA/RED and pixel 1687.58 for WA/BLUE.); - +Y axis is along the camera detector line and points in the same direction as the s/c +Y axis; - +X axis completes the right hand frame (X cross Y = Z); This picture illustrates the NA, WA_RED and WA_BLUE camera frames: ^+Zmoc | | +Xmoc.|. +Ymoc |o------> ._________________. .____|_|. ._________________. | \ | | / | | o| |o | | / | ^+Zsc \ | ._________________. .___|___. ._________________. | | | /__|__\ +Xsc and +Xmoc /_o------> +Ysc are out of the page +Xsc The block below provides the frame definition keyword sets for the MOC frames incorporating the rotation angles specified in the previous subsection (note the opposite sign/order of rotations in the definitions because the definitions contain the transformations from the camera frames to the spacecraft frame, see [1]): \begindata FRAME_MGS_MOC_NA = -94031 FRAME_-94031_NAME = 'MGS_MOC_NA' FRAME_-94031_CLASS = 4 FRAME_-94031_CLASS_ID = -94031 FRAME_-94031_CENTER = -94 TKFRAME_-94031_SPEC = 'ANGLES' TKFRAME_-94031_RELATIVE = 'MGS_SPACECRAFT' TKFRAME_-94031_ANGLES = ( -0.0020006709 0.0012500048 -0.0031415927 ) TKFRAME_-94031_AXES = ( 1, 2, 3 ) TKFRAME_-94031_UNITS = 'RADIANS' FRAME_MGS_MOC_WA_RED = -94032 FRAME_-94032_NAME = 'MGS_MOC_WA_RED' FRAME_-94032_CLASS = 4 FRAME_-94032_CLASS_ID = -94032 FRAME_-94032_CENTER = -94 TKFRAME_-94032_SPEC = 'ANGLES' TKFRAME_-94032_RELATIVE = 'MGS_SPACECRAFT' TKFRAME_-94032_ANGLES = ( -0.0182847674 0.0078939497 0.0137259674 ) TKFRAME_-94032_AXES = ( 1, 2, 3 ) TKFRAME_-94032_UNITS = 'RADIANS' FRAME_MGS_MOC_WA_BLUE = -94033 FRAME_-94033_NAME = 'MGS_MOC_WA_BLUE' FRAME_-94033_CLASS = 4 FRAME_-94033_CLASS_ID = -94033 FRAME_-94033_CENTER = -94 TKFRAME_-94033_SPEC = 'ANGLES' TKFRAME_-94033_RELATIVE = 'MGS_SPACECRAFT' TKFRAME_-94033_ANGLES = ( -0.0176316652 0.0061910319 0.0052689745 ) TKFRAME_-94033_AXES = ( 1, 2, 3 ) TKFRAME_-94033_UNITS = 'RADIANS' \begintext MHSA Frames ------------------------------------------------------------------------------- This section contains the definitions of the reference frames for the MGS Horizon Sensor Assembly (MHSA) and its detectors. The description and frame definition provided in this section were copied from the MHSA IK file ([6]). In the process, only the description was modified; the definitions were copied ``as is.'' MHSA Frames Summary ------------------- The following MHSA frames are defined in this kernel file: Frame Name "Relative to" Frame Frame Type Frame ID ====================== ===================== ============ ======== MGS_MHSA MGS_SPACECRAFT FIXED -94020 MGS_MHSA_D1 MGS_MHSA FIXED -94021 MGS_MHSA_D2 MGS_MHSA FIXED -94022 MGS_MHSA_D3 MGS_MHSA FIXED -94023 MGS_MHSA_D4 MGS_MHSA FIXED -94024 MHSA Frames Hierarchy --------------------- The diagram below shows the MHSA frames hierarchy: "J2000" +-----------------------------------------------+ | | | | <--pck | | <--pck V | V "IAU_MARS" | "IAU_EARTH" ---------- | ----------- | | <--ck | V "MGS_SPACECRAFT" ---------------- | | <--fixed | V "MGS_MHSA" +--------------------------------------------+ | | | | | <--fixed | <--fixed | <--fixed | <--fixed | | | | V V V V "MGS_MHSA_D1" "MGS_MHSA_D2" "MGS_MHSA_D3" "MGS_MHSA_D4" ------------- ------------- ------------- ------------- MHSA Mounting Offset -------------------- The offset of the MHSA instrument fixed frame relative to the Mars Global Surveyor spacecraft frame can be specified as the three rotation angles -- ROLL, PITCH and YAW. From these angles a rotation matrix can be constructed that will transform the components of a vector expressed in the spacecraft frame to components expressed in the MHSA instrument fixed frame. For example, if x y and z are the components of a vector expressed in the spacecraft frame, X Y and Z will be the components of the same vector expressed in the MHSA instrument fixed frame: [ X ] [ ] [ x ] | Y | = | ROT | | y | [ Z ] [ ] [ z ] where ROT is the rotation matrix constructed from the rotation angles as follows: [ ] [ ] [ ] [ ] [ ROT ] = [ YAW ] [ PITCH ] [ ROLL ] [ ] [ ] [ ] [ ] Z Y X where each of three matrices on the right side represent a coordinate frame rotation by the given angle around the indicated axis. The following values of ROLL, PITCH and YAW measured pre-launch give the alignment of the MHSA alignment cube: ROLL = 359.967 (degrees) PITCH = 0.037 (degrees) YAW = 359.974 (degrees) An additional -45 degree offset must be applied in YAW because the actual MHSA frame (or so called Barnes frame) in which the detector field of view vectors are defined is rotated relative to the alignment cube by that angle about Z axis. So YAW = ( 359.974 - 45.0 ) = 314.974 (degrees) MHSA Detectors Orientations --------------------------- The following text describes the MHSA detector view directions: For each MHSA quadrant, two angles are necessary to describe the field of view vectors in Barnes(*) frame. These angles are ALPHA and THETA. Following is the table showing the Barnes data: THETA ALPHA ----------- ----------- 1 44.85583 65.68686 2 45.11277 65.62951 3 45.18111 65.62672 4 44.81861 65.72406 ALPHA (A) is defined as the angle from Barnes Z axis to the field of view vector. In general, THETA (T) defines an angle from Barnes +/-Y axis to the projection of the field of view vector onto the Barnes XY plane. However, the precise definition of the angle depends on which quadrant it refers to. Following is a table which specifies how the field of view vectors were calculated in the Barnes frame, using the correct quadrant dependent definition of THETA. X Y Z ------------ ------------ ------- QUAD1 sin(A)sin(T) sin(A)cos(T) cos(A) QUAD2 -sin(A)sin(T) -sin(A)cos(T) cos(A) QUAD3 sin(A)sin(T) -sin(A)cos(T) cos(A) QUAD4 -sin(A)sin(T) sin(A)cos(T) cos(A) The angles ALPHA and THETA provided in the first table above in combination with the data from the second table can be easily transformed into two other angles (ALPHA' and THETA'), defining the rotations required to construct a rotation matrix that will transform the components of a vector expressed in the MHSA instrument fixed frame to the components of a vector expressed in a particular detector frame. The first of these angles, THETA', is the angle between +X axis of the Barnes frame and projection of the field of view vector onto the Barnes XY plane. It can be derived from THETA and corresponds to the first rotation about +Z axis of the Barnes frame. The second angle, ALPHA', is the same as ALPHA, i.e. it the angle from Barnes Z axis to the field of view vector. It corresponds to the second rotation about new position of the +Y axis of the Barnes frame. The derived values of the ALPHA' and THETA' are provided in the table below: THETA' ALPHA' ---------------------------- ----------- 1 ( 90 - 44.85583 ) = 45.14417 65.68686 2 ( 270 - 45.11277 ) = 224.88723 65.62951 3 ( 270 + 45.18111 ) = 315.18111 65.62672 4 ( 90 + 44.81861 ) = 134.81861 65.72406 The FOV vectors defined in the table above go through the geometrical centers of the detectors (i.e. centers of the circles circumscribing 4 elements of each FOV). To make the centers of the middle lower elements be FOV vectors, 2.7 degrees offset must be subtracted from ALPHA angle for each detector: THETA' ALPHA' ALPHA1' ---------------------------- ----------- ---------- 1 ( 90 - 44.85583 ) = 45.14417 65.68686 62.98686 2 ( 270 - 45.11277 ) = 224.88723 65.62951 62.92951 3 ( 270 + 45.18111 ) = 315.18111 65.62672 62.92672 4 ( 90 + 44.81861 ) = 134.81861 65.72406 63.02406 A rotation matrix transforming the components of a vector expressed in the MHSA instrument fixed frame to the components of a vector expressed in a particular detector frame can be constructed from these two rotation angles as follows: [ ] [ ] [ ] [ ROTi ] = [ ALPHA'i ] [ THETA'i ] [ ] [ ] [ ] Y Z where each of two matrices on the right side represent a coordinate frame rotation by the given angle around the indicated axis. Then given a X, Y and Z, the components of a vector expressed in the Barnes instrument fixed frame, the corresponding Xi, Yi and Zi, the components of the same vector expressed in the "i"th detector frame, can be calculated as follows: [ Xi ] [ ] [ x ] | Yi | = | ROTi | | y | [ Zi ] [ ] [ z ] where ROTi is the rotation matrix constructed from the corresponding rotation angles above MHSA Frame Definitions ---------------------- The block below provides the frame definition keyword sets for the MHSA frames incorporating the rotation angles specified in the previous two subsections (note the opposite sign/order of rotations in the definitions because the definitions contain the transformations from the instrument frames to the base frames, see [1]): \begindata FRAME_MGS_MHSA = -94020 FRAME_-94020_NAME = 'MGS_MHSA' FRAME_-94020_CLASS = 4 FRAME_-94020_CLASS_ID = -94020 FRAME_-94020_CENTER = -94 TKFRAME_-94020_SPEC = 'ANGLES' TKFRAME_-94020_RELATIVE = 'MGS_SPACECRAFT' TKFRAME_-94020_ANGLES = ( -6.282609348526, -0.000645771823, -5.497333358177 ) TKFRAME_-94020_AXES = ( 1, 2, 3 ) TKFRAME_-94020_UNITS = 'RADIANS' FRAME_MGS_MHSA_D1 = -94021 FRAME_-94021_NAME = 'MGS_MHSA_D1' FRAME_-94021_CLASS = 4 FRAME_-94021_CLASS_ID = -94021 FRAME_-94021_CENTER = -94 TKFRAME_-94021_SPEC = 'ANGLES' TKFRAME_-94021_RELATIVE = 'MGS_MHSA' TKFRAME_-94021_ANGLES = ( -0.7879144046, -1.0993280925, 0.0 ) TKFRAME_-94021_AXES = ( 3, 2, 3 ) TKFRAME_-94021_UNITS = 'RADIANS' FRAME_MGS_MHSA_D2 = -94022 FRAME_-94022_NAME = 'MGS_MHSA_D2' FRAME_-94022_CLASS = 4 FRAME_-94022_CLASS_ID = -94022 FRAME_-94022_CENTER = -94 TKFRAME_-94022_SPEC = 'ANGLES' TKFRAME_-94022_RELATIVE = 'MGS_MHSA' TKFRAME_-94022_ANGLES = ( -3.9250226092, -1.0983271462, 0.0 ) TKFRAME_-94022_AXES = ( 3, 2, 3 ) TKFRAME_-94022_UNITS = 'RADIANS' FRAME_MGS_MHSA_D3 = -94023 FRAME_-94023_NAME = 'MGS_MHSA_D3' FRAME_-94023_CLASS = 4 FRAME_-94023_CLASS_ID = -94023 FRAME_-94023_CENTER = -94 TKFRAME_-94023_SPEC = 'ANGLES' TKFRAME_-94023_RELATIVE = 'MGS_MHSA' TKFRAME_-94023_ANGLES = ( -5.5009481096, -1.0982784515, 0.0 ) TKFRAME_-94023_AXES = ( 3, 2, 3 ) TKFRAME_-94023_UNITS = 'RADIANS' FRAME_MGS_MHSA_D4 = -94024 FRAME_-94024_NAME = 'MGS_MHSA_D4' FRAME_-94024_CLASS = 4 FRAME_-94024_CLASS_ID = -94024 FRAME_-94024_CENTER = -94 TKFRAME_-94024_SPEC = 'ANGLES' TKFRAME_-94024_RELATIVE = 'MGS_MHSA' TKFRAME_-94024_ANGLES = ( -2.3530286375, -1.0999773550, 0.0 ) TKFRAME_-94024_AXES = ( 3, 2, 3 ) TKFRAME_-94024_UNITS = 'RADIANS' \begintext Solar Array and MAG/ER Sensor Frames ------------------------------------------------------------------------------- This section contains the definitions of the reference frames for the Magnetometer (MAG) sensors, Electron-Reflectometer (ER) sensor and the solar arrays. The description and most of the frame definitions provided in this section were copied from the MAG/ER IK file ([5]); the "MGS_LEFT_SOLAR_ARRAY" and "MGS_RIGHT_SOLAR_ARRAY" frame definitions were copied from the MGS SCLK file ([4]). In the process, only the description was modified; the definitions were copied ``as is.'' Solar Array and MAG/ER Frames Summary ------------------------------------- The following MGS solar array and MAG/ER frames are defined in this kernel file: Frame Name "Relative to" Frame Frame Type Frame ID ====================== ===================== ============ ======== MGS_LEFT_SOLAR_ARRAY MGS_SPACECRAFT CK -94001 MGS_RIGHT_SOLAR_ARRAY MGS_SPACECRAFT CK -94002 MGS_+Y_SOLAR_ARRAY MGS_LEFT_SOLAR_ARRAY FIXED -94901 MGS_-Y_SOLAR_ARRAY MGS_RIGHT_SOLAR_ARRAY CK -94902 MGS_MAG_+Y_SENSOR MGS_+Y_SOLAR_ARRAY FIXED -94051 MGS_MAG_-Y_SENSOR MGS_-Y_SOLAR_ARRAY FIXED -94052 MGS_ER MGS_SPACECRAFT FIXED -94053 Solar Array and MAG/ER Sensor Frames Hierarchy ---------------------------------------------- The diagram below shows the MGS Solar Array and MAG/ER frames hierarchy: "J2000" +-----------------------------------------------+ | | | | <--pck | | <--pck V | V "IAU_MARS" | "IAU_EARTH" ---------- | ----------- | | <--ck | V "MGS_SPACECRAFT" +-----------------------------------------------+ | | | | <--ck | | <--ck | | | V | V "MGS_RIGHT_SOLAR_ARRAY" | "MGS_LEFT_SOLAR_ARRAY" ----------------------- | ---------------------- | | | | <--ck | | <--fixed | | | V | V "MGS_-Y_SOLAR_ARRAY" | "MGS_+Y_SOLAR_ARRAY" -------------------- | -------------------- | | | | <--fixed | <--fixed | <--fixed | | | V V V "MGS_MAG_-Y_SENSOR" "MGS_ER" "MGS_MAG_+Y_SENSOR" ------------------- -------- ------------------- Solar Array and MAG/ER Frames Diagram ------------------------------------- The following diagrams shows the frames defined for the MGS solar arrays and MAG sensors: +Z | | *--- +Y +X / S/C body FR +Z (MGS_SPACECRAFT) +Z | +X | | |/ | | +Y ---* | *--- +Y | +X / -Y Gimbal FR | +Y Gimbal FR (MGS_RIGHT_ | (MGS_LEFT_ +Z +Z SOLAR_ARRAY) | SOLAR_ARRAY) | | +X | | | | |/ | | | *--- +Y +Y ---* | | | +X / -Y Yoke FR | | | +Y Yoke FR (MGS_+Y_SOLAR | | | (MGS_+Y_SOLAR _ARRAY) | | | _ARRAY) *--- +Y | | | | | *--- +Y /| | | | | | /| +Z | | | | | | +Z | +X | | | | | +X | | V | | -Y MAG sensor FR | | ______ | | +Y MAG sensor FR (MGS_MAG_-Y_SENSOR) | V / /| V | (MGS_MAG_+Y_SENSOR) | .___________|_ _____. /_____/ | .__|__ ___________|__. V / V// | | | | .' V // V / / -Y Solar // | | | | .' // +Y Solar / @ Array /@ @--| | ---@ @/ Array @ / // .' | | | | // / ._____________//_____.' | | ' |_____//_____________. ._____.' The "MGS_LEFT_SOLAR_ARRAY" and "MGS_RIGHT_SOLAR_ARRAY" frames are associated with the +Y and -Y solar array gimbals respectively. The orientation of these frames is provided in the CK files produced by the MGSSCK program at LMA. Note that there are no separate frames defined for inboard ("elevation") and outboard ("azimuth") gimbals for each solar array. Instead each pair of gimbals is considered as a single gimbal having two degrees of rotational freedom. These frames can be considered the "nominal" solar array position frames since they specify gimbal orientation and do not take into account any additional rotations that occured due to an incomplete deployment of the -Y array. The "MGS_+Y_SOLAR_ARRAY" and "MGS_-Y_SOLAR_ARRAY" frames are associated with the +Y and -Y solar array yokes respectively. These frames are defined relative to the corresponding gimbal frames Defining these frames was required because of the -Y solar array deployment failure, which introduced an additional rotation in the yoke for that panel. For the +Y panel this frame is co-aligned with the gimbal frame. The "MGS_MAG_+Y_SENSOR" and "MGS_MAG_-Y_SENSOR" frames are associated with the +Y and -Y MAG sensors. These frames are fixed offset frames whose orientation is specified by a set of Euler angles relative to the corresponding yoke frames. The "MGS_MAG_ER" frame is associated with the ER sensor. Because the ER sensor is rigidly mounted on the spacecraft, this frame is a fixed offset frame whose orientation is specified by a set of Euler angles relative to the spacecraft frame. Solar Array Gimbal and Yoke Frame Definitions --------------------------------------------- The +Y solar array gimbal frame ("MGS_LEFT_SOLAR_ARRAY") and the -Y solar array gimbal ("MGS_RIGHT_SOLAR_ARRAY") frames constantly change their orientation with respect to the spacecraft frame as they track the Sun. These frame are defined as CK-based frames with their orientation provided in the solar array CK files. The -Y solar array yoke frame ("MGS_-Y_SOLAR_ARRAY") is rotated by the hinge deflection angle about the X axis relative to the -Y solar array gimbal frame ("MGS_RIGHT_SOLAR_ARRAY"). Because the -Y solar array was not fully deployed causing this rotation to vary over time, this frame is defined as a CK-based frame with it orientation stored in the hinge deflection CK file. The +Y solar array yoke frame("MGS_+Y_SOLAR_ARRAY") is co-aligned with the +Y solar array gimbal frame ("MGS_LEFT_SOLAR_ARRAY") frame. It is defined as a fixed offset frame. The block below provides the frame definition keyword sets for the SA gimbal and yoke frames: \begindata FRAME_MGS_LEFT_SOLAR_ARRAY = -94001 FRAME_-94001_NAME = 'MGS_LEFT_SOLAR_ARRAY' FRAME_-94001_CLASS = 3 FRAME_-94001_CLASS_ID = -94001 FRAME_-94001_CENTER = -94 CK_-94001_SCLK = -94 CK_-94001_SPK = -94 FRAME_MGS_+Y_SOLAR_ARRAY = -94901 FRAME_-94901_NAME = 'MGS_+Y_SOLAR_ARRAY' FRAME_-94901_CLASS = 4 FRAME_-94901_CLASS_ID = -94901 FRAME_-94901_CENTER = -94 TKFRAME_-94901_SPEC = 'ANGLES' TKFRAME_-94901_RELATIVE = 'MGS_LEFT_SOLAR_ARRAY' TKFRAME_-94901_ANGLES = ( 0.0, 0.0, 0.0 ) TKFRAME_-94901_AXES = ( 1, 2, 3 ) TKFRAME_-94901_UNITS = 'DEGREES' FRAME_MGS_RIGHT_SOLAR_ARRAY = -94002 FRAME_-94002_NAME = 'MGS_RIGHT_SOLAR_ARRAY' FRAME_-94002_CLASS = 3 FRAME_-94002_CLASS_ID = -94002 FRAME_-94002_CENTER = -94 CK_-94002_SCLK = -94 CK_-94002_SPK = -94 FRAME_MGS_-Y_SOLAR_ARRAY = -94902 FRAME_-94902_NAME = 'MGS_-Y_SOLAR_ARRAY' FRAME_-94902_CLASS = 3 FRAME_-94902_CLASS_ID = -94902 FRAME_-94902_CENTER = -94 CK_-94902_SCLK = -94 CK_-94902_SPK = -94 \begintext MAG Sensor Frames Definitions ----------------------------- The +Y MAG sensor frame ("MGS_MAG_+Y_SENSOR") is rotated +90 degrees about the +Y axis relative to the +Y solar array yoke frame ("MGS_+Y_SOLAR_ARRAY"). The -Y MAG sensor frame ("MGS_MAG_-Y_SENSOR") is first rotated -90 degrees about the +Y axis, and then rotated +180 degrees about the new position of the +Z axis relative to the -Y solar array yoke frame ("MGS_+Y_SOLAR_ARRAY"). Since the orientation of both MAG sensor frames is fixed with respect to the corresponding yoke frames, their frames are defined as fixed offset frames. The block below provides the frame definition keyword sets for the MAG sensor frames (note the opposite sign/order of rotations in the definitions because the definitions contain the transformation from the sensor frames to the yoke frames, see [1]): \begindata FRAME_MGS_MAG_+Y_SENSOR = -94051 FRAME_-94051_NAME = 'MGS_MAG_+Y_SENSOR' FRAME_-94051_CLASS = 4 FRAME_-94051_CLASS_ID = -94051 FRAME_-94051_CENTER = -94 TKFRAME_-94051_SPEC = 'ANGLES' TKFRAME_-94051_RELATIVE = 'MGS_+Y_SOLAR_ARRAY' TKFRAME_-94051_ANGLES = ( 0.0, -90.0, 0.0 ) TKFRAME_-94051_AXES = ( 1, 2, 3 ) TKFRAME_-94051_UNITS = 'DEGREES' FRAME_MGS_MAG_-Y_SENSOR = -94052 FRAME_-94052_NAME = 'MGS_MAG_-Y_SENSOR' FRAME_-94052_CLASS = 4 FRAME_-94052_CLASS_ID = -94052 FRAME_-94052_CENTER = -94 TKFRAME_-94052_SPEC = 'ANGLES' TKFRAME_-94052_RELATIVE = 'MGS_-Y_SOLAR_ARRAY' TKFRAME_-94052_ANGLES = ( 0.0, 90.0, 180.0 ) TKFRAME_-94052_AXES = ( 1, 2, 3 ) TKFRAME_-94052_UNITS = 'DEGREES' \begintext ER Sensor Frame Definition -------------------------- The ER instrument frame ("MGS_ER") +Z axis lies in the S/C XY plane, 10 degrees from the -X axis in the direction of the -Y axis. The ER frame is defined as a fixed-fixed offset frame because the sensor is rigidly mounted on the spacecraft bus. The block below provides the frame definition keyword set for the ER sensor frame (note the opposite sign/order of rotations in the definition because the definition contain the transformation from the sensor frame to the spacecraft frame, see [1]): \begindata FRAME_MGS_ER = -94053 FRAME_-94053_NAME = 'MGS_ER' FRAME_-94053_CLASS = 4 FRAME_-94053_CLASS_ID = -94053 FRAME_-94053_CENTER = -94 TKFRAME_-94053_SPEC = 'ANGLES' TKFRAME_-94053_RELATIVE = 'MGS_SPACECRAFT' TKFRAME_-94053_ANGLES = ( 0.0, 90.0, -10.0 ) TKFRAME_-94053_AXES = ( 3, 2, 1 ) TKFRAME_-94053_UNITS = 'DEGREES' \begintext Antenna Frames ------------------------------------------------------------------------------- This section contains the definitions of the reference frames for the High Gain Antenna (HGA) and Low Gain Transmit (LGT) and Receive (LGR) antennas. The description and frame definitions provided in this section were copied from the MGS HGA FK file ([10]). In the process, only the description was modified; the definitions were copied ``as is.'' Antenna Description ------------------- The following text describes the MGS antennas: The MGS spacecraft is equipped with High Gain Antenna (HGA) and four low-gain antennas (LGA), two for transmit and two for receive. The HGA is mounted on the boom attached by a hinge to the +X side of the AFT deck of the spacecraft propulsion module. The HGA boresight direction is fixed and co-aligned with the spacecraft +X axis when antenna is in the stowed configuration (during cruise and aerobraking phases of the mission.) After the HGA is deployed for mapping operations, its pointing is achieved by rotation of the azimuth and elevation gimbals. Both transmitting LGAs are mounted to the TWA Enclosure Box which is itself mounted to the HGA reflector. One of the transmit LGAs (LGT1) is co-aligned with the HGA boresight (nominally in the +X direction while the antenna is stowed), while the other's (LGT2) boresight is oriented approximately 160 degrees away from this axis (near the -X axis while the HGA is stowed). The two receive LGAs are mounted on the -X panel of the equipment module (LGR2) and the +X side of the propulsion module (LGR1). HGA Hinge Geometry ------------------ The following text describes the MGS HGA boom hinge: The MGS HGA deployment hinge is a mechanism attaching the HGA boom to the +X side of the AFT deck of the propulsion module. During transition from aerobraking to mapping, the locks holding antenna in stowed configuration get released and, driven by the spring, the hinge rotates from stowed to deployed position and locks in deployed position for the rest of the mission. The hinge rotation axis is parallel to the s/c Y axis. In the stowed configuration the antenna boom is parallel to the s/c Z axis. In the deployed configuration the boom is parallel to the s/c XZ plane and is rotated by 5 degrees from the s/c -Z axis towards the s/c +X axis. The full nominal deployment angle between stowed and deployed positions is 175 degrees. There is no direct measurement of the hinge deployment angle available in the s/c engineering telemetry after antenna is deployed. The deployment actual angle is planned to be estimated from signal strength during the initial HGA calibration tests. HGA Gimbal Geometry ------------------- The following text describes the MGS HGA gimbals: The MGS HGA Gimbal assembly is a mechanism attaching the HGA reflector to the end of the HGA boom. It consists of two independent gimbals -- elevation (EL) and azimuth (AZ) gimbals -- and is used to achieve antenna pointing in deployed configuration. The first of them -- EL gimbal -- is attached to the antenna boom. The second -- AZ gimbal -- is attached by one side to the first gimbal with a "corner-like" fitting and by the opposite side to the antenna reflector. The EL gimbal rotation axis is parallel to the deployment hinge rotation axis. The AZ gimbal rotation axis is perpendicular to the EL gimbal rotation axis and parallel to the s/c XZ and the antenna reflector rim circle planes. The gimbals have the following hard/soft stop positions determining limits of the rotation ranges: Soft Stops: azimuth: -8 deg ... +81 deg elevation: -153 deg ... +153 deg Hard stops: azimuth: -30 deg ... +190 deg elevation: -158 deg ... +158 deg "Zero" angle position (EL=0,AZ=0) puts the HGA boresight vector parallel to the -Z axis of the spacecraft. Other recognized antenna positions include: Stowed Position: azimuth: +180 deg elevation: -95 deg Initial Deployed azimuth: 0 deg Position: elevation: -90 deg Park Position: azimuth: 80 deg elevation: -120 deg The antenna gimbal angle values are available in the spacecraft engineering telemetry channels: F-0190 (HGA_AZ_ANG), Azimuth Angles F-0195 (HGA_EL_ANG), Elevation Angles at the s/c housekeeping medium rate i.e. once every 32 seconds. The angle value are downlinked in radians. There are also three additional HGA data telemetry channels: F-0193 (HGA_AZ_TRG), Azimuth Targets F-0198 (HGA_EL_TRG), Elevation Targets F-0200 (HGA_STATS), HGA Status words the first two of which give the expected final values +-0.04 degrees of the panels when motion is commanded and which are unnecessary for the computation of the gimbal rotations. During mapping, movement of the of the azimuth gimbal is in general fixed for a given orbit. For a fixed azimuth position, the elevation gimbal angle is varied to provide proper pointing throughout the orbit. Antenna Frames Summary ---------------------- The following MGS Antenna frames are defined in this kernel file: Frame Name "Relative to" Frame Frame Type Frame ID ====================== ===================== ============ ======== MGS_HGA_HINGE MGS_SPACECRAFT CK -94070 MGS_HGA_EL_GIMBAL MGS_HGA_HINGE CK -94071 MGS_HGA_AZ_GIMBAL MGS_HGA_EL_GIMBAL CK -94072 MGS_HGA MGS_HGA_AZ_GIMBAL FIXED -94073 MGS_LGT1 MGS_HGA FIXED -94074 MGS_LGT2 MGS_HGA FIXED -94075 MGS_LGR1 MGS_SPACECRAFT FIXED -94076 MGS_LGR2 MGS_SPACECRAFT FIXED -94077 Antenna Frames Hierarchy ------------------------ The diagram below shows the MGS Antenna frames hierarchy: "J2000" +-----------------------------------------------+ | | | | <--pck | | <--pck V | V "IAU_MARS" | "IAU_EARTH" ---------- | ----------- | | <--ck | V "MGS_SPACECRAFT" +-----------------------------------------------+ | | | | <--fixed | <--ck | <--fixed | | | V V V "MGS_LGR1" "MGS_HGA_HINGE" "MGS_LGR2" ---------- --------------- ---------- | | <--ck | V "MGS_HGA_EL_GIMBAL" ------------------- | | <--ck | V "MGS_HGA_AZ_GIMBAL" ------------------- | | <--fixed | V "MGS_HGA" +-----------------------------------------------+ | | | <--fixed | <--fixed | | V V "MGS_LGT1" "MGS_LGT2" ---------- ---------- HGA Frame Definitions --------------------- The MGS HGA deploy hinge frame is defined as follows: - Z axis is along the deploy hinge rotation axis, and is parallel to and points in the same direction as the s/c frame +Y axis; - X axis is perpendicular to the hinge rotation axis, parallel to the HGA boom central axis and points along it from the deploy hinge side towards the elevation gimbal side; - Y axis completes the right hand frame; - the origin of this frame is located at the intersection of the hinge rotation axis and the plane perpendicular to the rotation axis and containing the central axis of the boom. The MGS HGA elevation gimbal frame is defined as follows: - Z axis is along the elevation gimbal rotation axis and points from the HGA boom side towards the azimuth gimbal side; - X axis is perpendicular to the elevation gimbal rotation axis, parallel to the azimuth gimbal rotation axis and points from the elevation gimbal side towards the HGA reflector mounting side; - Y axis completes the right hand frame; - the origin of this frame is located at the intersection of the elevation gimbal rotation axis and the plane perpendicular to this rotation axis and containing the azimuth gimbal rotation axis. The MGS HGA azimuth gimbal frame is defined as follows: - Z axis is along the azimuth gimbal rotation axis and points from the elevation gimbal side towards the HGA reflector mounting side; - X axis is perpendicular to the azimuth gimbal rotation axis, parallel to the plane containing the HGA reflector rim circle and points from the azimuth gimbal towards the HGA rim circle center; - Y axis completes the right hand frame; - the origin of this frame is located at the intersection of the azimuth gimbal rotation axis and the plane perpendicular to this rotation axis and containing the HGA reflector central symmetry axis (boresight axis). The MGS HGA boresight frame is defined as follows: - Z axis is along the HGA reflector central symmetry axis (boresight axis) and points from the reflector surface towards the feed horn; - X axis is perpendicular to the boresight direction, perpendicular to azimuth gimbal rotation axis and points from the antenna symmetry axis towards the side of the reflector to which the azimuth gimbal is attached; - Y axis completes the right hand frame; - the origin of this frame is located at the intersection of the antenna reflector symmetry axis and the plane containing HGA reflector rim circle. The diagram below illustrates the HGA hinge/gimbal/boresight frames (the antenna is shown in the configuration when the boom is fully extended along the s/c +X axis, the elevation and azimuth gimbal axes are in the s/c plane, and the antenna boresight points along the s/c +Z axis): Top view (+Zsc view): --------------------- * * * * * * * * * * * * * * * * * * +Zb o----> +Yb * * | * * | * * v +Xb * * * * ^ * ^ +Zel * |+Xaz *____ | * | __| |____|_ <----x__*___| +Xel<----o|+Yel +Zaz +Yaz |_____| | | azimuth _|_|_ ____________ +Zh gimbal | | elev. | ^ | | gimbal +Ysc |_|__ |_____| ^ +Yh| |___________________________________| | | | x---->___________________________________| | +Xsc |_____| +Xh o----> | deployment +Zsc | hinge | | | ____________| Side view (-Ysc view): ---------------------- ^ +Zb | | | +Yb | ___________o---->______ +Yel | \__ +Xb __/ ^ |___ \__ __/____ _|_ /+Zh\_______________\__+Xaz __/_| |_/ | \ ____________| x---->____________<----x______| +Xel<---x +Zel ^+Zsc \_|_/ +Xh +Zaz | |_____| \___/ | \ | | | +Xsc V +Yh v +Yaz ___x--->_\ +Ysc On the diagram: +Xsc,+Ysc,+Zsc -- axes of the s/c frame; +Xh, +Yh, +Zh -- axes of the hinge frame; +Xel,+Yel,+Zel -- axes of the elevation gimbal frame; +Xaz,+Yaz,+Zaz -- axes of the azimuth gimbal frame; +Xb, +Yb, +Zb -- axes of the HGA boresight frame; "o" shows axes pointing "out of the page", "x" shows axes pointing "into the page" As follows from the definition, the HGA boresight frame is rotated from the azimuth gimbal frame by two rotations -- first by +90 degrees about the +X axis and second by +180 degrees about the +Z axis. The block below provides the frame definition keyword sets for the HGA hinge/gimbal/boresight frames (note the opposite sign/order of rotations in the MGS_HGA definition because the definition contains the transformation from the antenna to the reference frame, see [1]): \begindata FRAME_MGS_HGA_HINGE = -94070 FRAME_-94070_NAME = 'MGS_HGA_HINGE' FRAME_-94070_CLASS = 3 FRAME_-94070_CLASS_ID = -94070 FRAME_-94070_CENTER = -94 CK_-94070_SCLK = -94 CK_-94070_SPK = -94 FRAME_MGS_HGA_EL_GIMBAL = -94071 FRAME_-94071_NAME = 'MGS_HGA_EL_GIMBAL' FRAME_-94071_CLASS = 3 FRAME_-94071_CLASS_ID = -94071 FRAME_-94071_CENTER = -94 CK_-94071_SCLK = -94 CK_-94071_SPK = -94 FRAME_MGS_HGA_AZ_GIMBAL = -94072 FRAME_-94072_NAME = 'MGS_HGA_AZ_GIMBAL' FRAME_-94072_CLASS = 3 FRAME_-94072_CLASS_ID = -94072 FRAME_-94072_CENTER = -94 CK_-94072_SCLK = -94 CK_-94072_SPK = -94 FRAME_MGS_HGA = -94073 FRAME_-94073_NAME = 'MGS_HGA' FRAME_-94073_CLASS = 4 FRAME_-94073_CLASS_ID = -94073 FRAME_-94073_CENTER = -94 TKFRAME_-94073_SPEC = 'ANGLES' TKFRAME_-94073_RELATIVE = 'MGS_HGA_AZ_GIMBAL' TKFRAME_-94073_ANGLES = ( -90.0, 0.0, 180.0 ) TKFRAME_-94073_AXES = ( 1, 2, 3 ) TKFRAME_-94073_UNITS = 'DEGREES' \begintext Transmit LGA Frame Definitions ------------------------------ The MGS LGT1 boresight frame is defined as follows: - Z axis is perpendicular to the antenna "patch" surface and points away from its surface; - X axis is parallel to the line connecting the "patch" center with the "patch" corner farthest from both antenna connectors attached to the bottom side of the patch and points from the center towards the corner; - Y axis completes the right hand frame; - the origin of this frame is located at the geometric center of the antenna "patch" square. The MGS LGT2 boresight frame is defined as follows: - Z axis is perpendicular to the antenna "patch" surface and points away from the surface; - X axis is parallel to the line connecting the "patch" center with the "patch" corner farthest from both antenna connectors attached to the bottom side of the patch and points from the center towards the corner; - Y axis completes the right hand frame; - the origin of this frame is located at the geometric center of the antenna "patch" square. As follows from the definitions, the LGT1 frame is rotated from the HGA boresight frame by +214 degrees about the +Z axis (34 degrees due to the TWA box mounting on the HGA reflector plus 180 degrees due to the "patch" orientation with respect to the bracket of which it is mounted.) The LGT2 frame is first rotated +34 degrees about the +Z axis (due to the TWA box mounting on the HGA reflector), after that it is rotated by -130.88 degrees about the new direction of +Y axis and at last it is rotated -10.4 degrees about the new direction of +X axis (last two rotations are due to the "sophisticated" geometry of the lower LGT2 mounting bracket.) The block below provides the frame definition keyword sets for the LGT1 and LGT2 frames, which incorporate these rotations (note the opposite sign/order of rotations because the definitions contains the transformations from the antenna to the reference frame, see [1]): \begindata FRAME_MGS_LGT1 = -94074 FRAME_-94074_NAME = 'MGS_LGT1' FRAME_-94074_CLASS = 4 FRAME_-94074_CLASS_ID = -94074 FRAME_-94074_CENTER = -94 TKFRAME_-94074_SPEC = 'ANGLES' TKFRAME_-94074_RELATIVE = 'MGS_HGA' TKFRAME_-94074_ANGLES = ( -214.0, 0.0, 0.0 ) TKFRAME_-94074_AXES = ( 3, 2, 1 ) TKFRAME_-94074_UNITS = 'DEGREES' FRAME_MGS_LGT2 = -94075 FRAME_-94075_NAME = 'MGS_LGT2' FRAME_-94075_CLASS = 4 FRAME_-94075_CLASS_ID = -94075 FRAME_-94075_CENTER = -94 TKFRAME_-94075_SPEC = 'ANGLES' TKFRAME_-94075_RELATIVE = 'MGS_HGA' TKFRAME_-94075_ANGLES = ( -34.0, 130.0, 10.4 ) TKFRAME_-94075_AXES = ( 3, 2, 1 ) TKFRAME_-94075_UNITS = 'DEGREES' \begintext Receive LGA Frame Definitions ----------------------------- The MGS LGR1 boresight frame is defined as follows: - Z axis is perpendicular to the antenna "patch" surface, and is parallel and points in the same direction as the s/c +X axis; - Y axis is parallel to and points in the same direction as the s/c +Y axis; - X axis completes the right hand frame; - the origin of this frame is located at the geometric center of the antenna "patch" square. The MGS LGR2 boresight frame is defined as follows: - Z axis is perpendicular to the antenna "patch" surface, and is parallel and points in the same direction as the s/c -X axis; - Y axis is parallel to and points in the same direction as the s/c +Y axis; - X axis completes the right hand frame; - the origin of this frame is located at the geometric center of the antenna "patch" square. As follows from the definitions, the LGR1 frame is rotated from the spacecraft frame by +90 degrees about the +Y axis and the LRG2 frame is rotated from the spacecraft frame by -90 degrees about the +Y axis. The diagram below illustrates the LGR1 and LGR2 frames: Side View (-Ysc): ----------------- LGT2 ____ LGT1 @=| |=@ | |_ |__ / | ___________ / | +Xlgr2 | | / | ^ | | / | | | || | +Zlgr2 | | || | HGA <----x=| || | +Ylgr2|___________| \ | | | \ | | | \ | | | \__| | | | +Ylgr1 | |=x----> |___________| | +Zlgr1 +Zsc \ | / ^ \ v / | \ +Xlgr1 / | \ /_____x----> +Ysc +Xsc On the diagram: +Xsc, +Ysc, +Zsc -- axes of the s/c frame; +Xlgr1, +Ylgr1, +Zlgr1 -- axes of the LGR1 frame; +Xlgr2, +Ylgr2, +Zlgr2 -- axes of the LGR2 frame; "x" shows axes pointing "into the page" The block below provides the frame definition keyword sets for the LGR1 and LGR2 frames, which incorporate these rotations (note the opposite sign/order of rotations because the definitions contains the transformation from the antenna to the reference frame, see [1]): \begindata FRAME_MGS_LGR1 = -94076 FRAME_-94076_NAME = 'MGS_LGR1' FRAME_-94076_CLASS = 4 FRAME_-94076_CLASS_ID = -94076 FRAME_-94076_CENTER = -94 TKFRAME_-94076_SPEC = 'ANGLES' TKFRAME_-94076_RELATIVE = 'MGS_SPACECRAFT' TKFRAME_-94076_ANGLES = ( 0.0, -90.0, 0.0 ) TKFRAME_-94076_AXES = ( 3, 2, 1 ) TKFRAME_-94076_UNITS = 'DEGREES' FRAME_MGS_LGR2 = -94077 FRAME_-94077_NAME = 'MGS_LGR2' FRAME_-94077_CLASS = 4 FRAME_-94077_CLASS_ID = -94077 FRAME_-94077_CENTER = -94 TKFRAME_-94077_SPEC = 'ANGLES' TKFRAME_-94077_RELATIVE = 'MGS_SPACECRAFT' TKFRAME_-94077_ANGLES = ( 0.0, 90.0, 0.0 ) TKFRAME_-94077_AXES = ( 3, 2, 1 ) TKFRAME_-94077_UNITS = 'DEGREES' \begintext Mars Global Surveyor NAIF ID Codes Definitions ------------------------------------------------------------------------------- This section contains name - to - NAIF ID mappings for the MGS mission. Once the contents of this file is loaded into the KERNEL POOL, these mappings become available within SPICE, making it possible to use these names in the high level SPICE routine calls. Spacecraft: ----------- MARS GLOBAL SURVEYOR -94 MGS -94 MGS_SPACECRAFT_BUS -94000 MGS_SC_BUS -94000 MGS_SPACECRAFT -94000 Science Instruments: -------------------- MGS_TES -94010 MGS_MHSA -94020 MGS_MHSA_D1 -94021 MGS_MHSA_D2 -94022 MGS_MHSA_D3 -94023 MGS_MHSA_D4 -94024 MGS_MOC -94030 MGS_MOC_NA -94031 MGS_MOC_WA_RED -94032 MGS_MOC_WA_BLUE -94033 MGS_MOLA -94040 MGS_MAG_+Y_SENSOR -94051 MGS_MAG_-Y_SENSOR -94052 MGS_ER -94053 Antennas: --------- MGS_HGA_HINGE -94070 MGS_HGA_EL_GIMBAL -94071 MGS_HGA_AZ_GIMBAL -94072 MGS_HGA -94073 MGS_HGA_PHASE_CENTER -94078 MGS_LGT1 -94074 MGS_LGT2 -94075 MGS_LGR1 -94076 MGS_LGR2 -94077 Solar Arrays: ------------- MGS_+Y_GIMBAL -94001 MGS_-Y_GIMBAL -94002 MGS_+Y_YOKE -94901 MGS_-Y_YOKE -94902 The mappings summarized in this table are implemented by the keywords below. \begindata NAIF_BODY_NAME += ( 'MARS GLOBAL SURVEYOR' ) NAIF_BODY_CODE += ( -94 ) NAIF_BODY_NAME += ( 'MGS' ) NAIF_BODY_CODE += ( -94 ) NAIF_BODY_NAME += ( 'MGS_SPACECRAFT_BUS' ) NAIF_BODY_CODE += ( -94000 ) NAIF_BODY_NAME += ( 'MGS_SC_BUS' ) NAIF_BODY_CODE += ( -94000 ) NAIF_BODY_NAME += ( 'MGS_SPACECRAFT' ) NAIF_BODY_CODE += ( -94000 ) NAIF_BODY_NAME += ( 'MGS_TES' ) NAIF_BODY_CODE += ( -94010 ) NAIF_BODY_NAME += ( 'MGS_MHSA' ) NAIF_BODY_CODE += ( -94020 ) NAIF_BODY_NAME += ( 'MGS_MHSA_D1' ) NAIF_BODY_CODE += ( -94021 ) NAIF_BODY_NAME += ( 'MGS_MHSA_D2' ) NAIF_BODY_CODE += ( -94022 ) NAIF_BODY_NAME += ( 'MGS_MHSA_D3' ) NAIF_BODY_CODE += ( -94023 ) NAIF_BODY_NAME += ( 'MGS_MHSA_D4' ) NAIF_BODY_CODE += ( -94024 ) NAIF_BODY_NAME += ( 'MGS_MOC' ) NAIF_BODY_CODE += ( -94030 ) NAIF_BODY_NAME += ( 'MGS_MOC_NA' ) NAIF_BODY_CODE += ( -94031 ) NAIF_BODY_NAME += ( 'MGS_MOC_WA_RED' ) NAIF_BODY_CODE += ( -94032 ) NAIF_BODY_NAME += ( 'MGS_MOC_WA_BLUE' ) NAIF_BODY_CODE += ( -94033 ) NAIF_BODY_NAME += ( 'MGS_MOLA' ) NAIF_BODY_CODE += ( -94040 ) NAIF_BODY_NAME += ( 'MGS_MAG_+Y_SENSOR' ) NAIF_BODY_CODE += ( -94051 ) NAIF_BODY_NAME += ( 'MGS_MAG_-Y_SENSOR' ) NAIF_BODY_CODE += ( -94052 ) NAIF_BODY_NAME += ( 'MGS_ER' ) NAIF_BODY_CODE += ( -94053 ) NAIF_BODY_NAME += ( 'MGS_HGA_HINGE' ) NAIF_BODY_CODE += ( -94070 ) NAIF_BODY_NAME += ( 'MGS_HGA_EL_GIMBAL' ) NAIF_BODY_CODE += ( -94071 ) NAIF_BODY_NAME += ( 'MGS_HGA_AZ_GIMBAL' ) NAIF_BODY_CODE += ( -94072 ) NAIF_BODY_NAME += ( 'MGS_HGA' ) NAIF_BODY_CODE += ( -94073 ) NAIF_BODY_NAME += ( 'MGS_HGA_PHASE_CENTER' ) NAIF_BODY_CODE += ( -94078 ) NAIF_BODY_NAME += ( 'MGS_LGT1' ) NAIF_BODY_CODE += ( -94074 ) NAIF_BODY_NAME += ( 'MGS_LGT2' ) NAIF_BODY_CODE += ( -94075 ) NAIF_BODY_NAME += ( 'MGS_LGR1' ) NAIF_BODY_CODE += ( -94076 ) NAIF_BODY_NAME += ( 'MGS_LGR2' ) NAIF_BODY_CODE += ( -94077 ) NAIF_BODY_NAME += ( 'MGS_+Y_GIMBAL' ) NAIF_BODY_CODE += ( -94001 ) NAIF_BODY_NAME += ( 'MGS_-Y_GIMBAL' ) NAIF_BODY_CODE += ( -94002 ) NAIF_BODY_NAME += ( 'MGS_+Y_YOKE' ) NAIF_BODY_CODE += ( -94901 ) NAIF_BODY_NAME += ( 'MGS_-Y_YOKE' ) NAIF_BODY_CODE += ( -94902 ) \begintext