KPL/IK NEAR Near-Infrared Spectrograph (NIS) instrument and frame kernel file ---------------------------------------------------------------------- Version 1.4, by Jeff Bytof, NAIF/JPL, 14 August 1998 (1) Modified the Euler angles needed to move the NEAR_NIS_BASE reference frame into the NEAR_SC_BUS_PRIME frame. Calibrated boresight data provided by Yanping Guo (JHU/APL), dated 13 August 1998, is as follows: ----------------------------------------------------- Instrument Zenith Angle off Azimuth Angle off +Z S/C Axis (deg) +X' S/C Axis (deg) ----------------- ------------------ NIS 89.8581 -0.1408 ----------------------------------------------------- The zenith angle is measured from the spacecraft +Z axis to the instrument boresight, and the azimuth angle is measured counterclockwise from the spacecraft +X' axis to the boresight. The NEAR_NIS_BASE "boresight" is defined to be identical to the +X unit vector of its reference frame. Using the Euler angles given in this kernel, the components of the NEAR_NIS_BASE frame relative to the NEAR_SC_BUS_PRIME frame are found by the SPICE subroutine SXFORM to be as follows: X: .9999939137 -.0024574136 .0024766197 Y: .0024574211 .9999969805 .0000000000 Z: -.0024766122 .0000060861 .9999969332 This indicates that the NEAR_NIS_BASE "boresight" points towards (.9999939137, -.0024574136, .0024766197) as measured in the NEAR_SC_BUS_PRIME frame. (2) Corrected the SPICE file ID word to KPL/IK. Version 1.3 (prototype) by JAB, NAIF/JPL, March 17, 1998 Two instruments were added with codes -93023 and -93024 that reference the NEAR_NIS_BASE frame directly, bypassing the NEAR_NIS_MIRROR frame. They have the same FOV's as -93021 and -93022, respectively. Version 1.2 (prototype) by JAB, NAIF/JPL, September 11, 1997 SC_BUS frame definitions were swapped with SC_BUS_PRIME, to follow the NEAR project's use of the code -93000 for the SC_BUS_PRIME frame. Version 1.1 (prototype) by BVS, NAIF/JPL, August 11, 1997 The frame definitions were changed to reflect correct transformation sense specified by FRAMES.REQ document released in SPICE toolkit N0047. Version 1.0 (prototype) by BVS, NAIF/JPL, April 16, 1997 Spacecraft frame definitions. Required to support automatic frame transformations. Two frames are defined for NEAR s/c: - s/c frame (or s/c technological frame); - s/c prime frame; rotated -135 degrees around Z relative to the s/c frame; Orientation of the first frame is provided in CK files relative to some inertial or non-inertial frame; orientation of the second frame is a constant offset from the first frame specified in the frame definition. Note that these definitions are duplicated in IK files for all other NEAR instruments. Note that angles in the frame definitions are specified for "from instrument to base (relative to) frame" transformation. \begindata FRAME_NEAR_SC_BUS_PRIME = -93000 FRAME_-93000_NAME = 'NEAR_SC_BUS_PRIME' FRAME_-93000_CLASS = 3 FRAME_-93000_CLASS_ID = -93000 FRAME_-93000_CENTER = -93 CK_-93000_SCLK = -93 CK_-93000_SPK = -93 FRAME_NEAR_SC_BUS = -93100 FRAME_-93100_NAME = 'NEAR_SC_BUS' FRAME_-93100_CLASS = 4 FRAME_-93100_CLASS_ID = -93100 FRAME_-93100_CENTER = -93 TKFRAME_-93100_SPEC = 'ANGLES' TKFRAME_-93100_RELATIVE = 'NEAR_SC_BUS_PRIME' TKFRAME_-93100_ANGLES = ( -135.0, 0.0, 0.0 ) TKFRAME_-93100_AXES = ( 3, 2, 1 ) TKFRAME_-93100_UNITS = 'DEGREES' \begintext NIS instrument frames definition. Required to support automatic frame transformations. Since the instrument has a moving mirror, two frames are defined for it. First frame is an instrument mounting frame which is fixed to the instrument structure. Its orientation is a constant offset from s/c prime frame. Second frame is a mirror frame which is defined by to the reflected boresight direction (not the mirror itself). The orientation of this frame is provided in a CK files relative to the instrument mounting or other inertial or non-inertial frame. Note that angles in the frame definitions are specified for "from instrument to base (relative to) frame" transformation. \begindata FRAME_NEAR_NIS_BASE = -93002 FRAME_-93002_NAME = 'NEAR_NIS_BASE' FRAME_-93002_CLASS = 4 FRAME_-93002_CLASS_ID = -93002 FRAME_-93002_CENTER = -93 TKFRAME_-93002_SPEC = 'ANGLES' TKFRAME_-93002_RELATIVE = 'NEAR_SC_BUS_PRIME' TKFRAME_-93002_ANGLES = ( 0.1408, 0.1419, 0.0 ) TKFRAME_-93002_AXES = ( 3, 2, 1 ) TKFRAME_-93002_UNITS = 'DEGREES' FRAME_NEAR_NIS_MIRROR = -93020 FRAME_-93020_NAME = 'NEAR_NIS_MIRROR' FRAME_-93020_CLASS = 3 FRAME_-93020_CLASS_ID = -93020 FRAME_-93020_CENTER = -93 CK_-93020_SCLK = -93 CK_-93020_SPK = -93 \begintext Instrument FOVs shape/orientation definitions. Conform to specification in the header of the GETFOV subroutine. Corner directions are given counterclockwise as seen from boresight. Since NIS has two different FOVs, there are specified separately in this IK file. Two different instrument ID codes are used for that: -93021 ID code is used for rectangular FOV (0.38 by 0.76 degrees) and -93022 ID code is used for square FOV (0.76 by 0.76 degrees) FOV corner directions are defined assuming that: - both FOVs have rectangular shape with the sides along Z and Y axes of the mirror frame; - FOV angular sizes in Z direction are 0.38 degrees for the first FOV and 0.76 degrees for the second FOV; in Y direction -- 0.76 degrees for both FOVs; - boresight vector intersects FOVs exactly in the center of the rectangles; \begindata INS-93021_FOV_FRAME = 'NEAR_NIS_MIRROR' INS-93021_FOV_SHAPE = 'POLYGON' INS-93021_BORESIGHT = ( 1.0 0.0 0.0 ) INS-93021_FOV_BOUNDARY_CORNERS = ( 1.0 0.006632348403 0.003316137734 1.0 -0.006632348403 0.003316137734 1.0 -0.006632348403 -0.003316137734 1.0 0.006632348403 -0.003316137734 ) INS-93022_FOV_FRAME = 'NEAR_NIS_MIRROR' INS-93022_FOV_SHAPE = 'POLYGON' INS-93022_BORESIGHT = ( 1.0 0.0 0.0 ) INS-93022_FOV_BOUNDARY_CORNERS = ( 1.0 0.006632348403 0.006632348403 1.0 -0.006632348403 0.006632348403 1.0 -0.006632348403 -0.006632348403 1.0 0.006632348403 -0.006632348403 ) \begintext The following instruments have the same FOV's as -93021 and -93022, but only reference the NEAR_NIS_BASE frame, bypassing the NEAR_NIS_MIRROR frame. \begindata INS-93023_FOV_FRAME = 'NEAR_NIS_BASE' INS-93023_FOV_SHAPE = 'POLYGON' INS-93023_BORESIGHT = ( 1.0 0.0 0.0 ) INS-93023_FOV_BOUNDARY_CORNERS = ( 1.0 0.006632348403 0.003316137734 1.0 -0.006632348403 0.003316137734 1.0 -0.006632348403 -0.003316137734 1.0 0.006632348403 -0.003316137734 ) INS-93024_FOV_FRAME = 'NEAR_NIS_BASE' INS-93024_FOV_SHAPE = 'POLYGON' INS-93024_BORESIGHT = ( 1.0 0.0 0.0 ) INS-93024_FOV_BOUNDARY_CORNERS = ( 1.0 0.006632348403 0.006632348403 1.0 -0.006632348403 0.006632348403 1.0 -0.006632348403 -0.006632348403 1.0 0.006632348403 -0.006632348403 ) \begintext