KPL/IK VIRTIS Instrument kernel =========================================================================== This instrument kernel (I-kernel) contains Rosetta VIRTIS optics, detector, and field-of-view parameters. Version and Date --------------------------------------------------------------------------- Version 1.0 -- March 15, 2005 -- Boris Semenov, NAIF/JPL Version number change for the first official release. Version 0.3 -- March 15, 2005 -- Boris Semenov, NAIF/JPL Fixed VIRTIS-H FOV definition and relevant parameters and comments to align slit with the +X axis of the VIRTIS-H frame. Version 0.2 -- October 12, 2004 -- Boris Semenov, NAIF/JPL Fixed cut-n-paste errors (incorrect ID) in the keywords in the ``Detector Parameters'' section. Version 0.1 -- September 2, 2004 -- Boris Semenov, NAIF/JPL Filled in instrument overview section (copied from [6]). Version 0.0 -- August 4, 2004 -- Boris Semenov, NAIF/JPL VERY PRELIMINARY VERSION. References --------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. ``C-kernel Required Reading'' 3. ``VIRTIS EID, Part B'', ROS-EST-RS-30015/EID B, 2001-02-15 4. Rosetta Frames Definition Kernel (FK), latest version. 5. ``VIRTIS: Experiment User Manual'', RO-VIR-UM-001, 2002-05-10 6. ESA Science and Technology Web Server, Rosetta Instruments Area, http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35061 Implementation Notes -------------------------------------------------------- Applications that need SPICE I-kernel data must ``load'' the I-kernel file, normally during program initialization. Loading the kernel using the SPICELIB routine FURNSH causes the data items and their associated values present in the kernel to become associated with a data structure called the ``kernel pool''. The application program may then obtain the value(s) for any IK data item using the SPICELIB routines GDPOOL, GIPOOL, GCPOOL. Routine GETFOV may be used if the file contains instrument field-of-view (FOV) specification. See [1] for details. This file was created with, and can be updated with a text editor or word processor. Conventions for Specifying Data -------------------------------------------------------- Data items are specified using ``keyword=value'' assignments [1]. All keywords referencing values in this I-kernel start with the characters `INS' followed by the NAIF Rosetta instrument ID code, constructed using the spacecraft ID number (-226) followed by the NAIF three digit ID number for VIRTIS module. These IDs are defined in [4] as follows: Instrument name ID -------------------- ------- ROS_VIRTIS -226200 ROS_VIRTIS-M -226210 ROS_VIRTIS-M_VIS -226211 ROS_VIRTIS-M_VIS_SCAN -226212 (*) ROS_VIRTIS-M_IR -226213 ROS_VIRTIS-M_IR_SCAN -226214 (*) ROS_VIRTIS-H -226220 ROS_VIRTIS_URF -226230 (*) _SCAN names/IDs are defined to allow specifying a complete FOV resulting from side scan the VIRTIS-M scan mirror. The remainder of the keyword is an underscore character followed by the unique name of the data item. For example, the focal length of the VIRTIS-M VIS optics is specified by INS-226211_FOCAL_LENGTH The upper bound on the length of all keywords is 32 characters. If a keyword is included in more than one file, or if the same keyword appears more than once within a single file, the last assignment supersedes any earlier assignments. Overview -------------------------------------------------------- From [6]: VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) is an imaging spectrometer that combines three data channels in one instrument. Two of the data channels are designed to perform spectral mapping. The third channel is devoted to spectroscopy. Summary of VIRTIS Characteristics Spectral range (mkm): Mapping Spectrometer - Visible --- 0.25 - 1.0 Mapping Spectrometer - Infrared --- 0.95 - 5 Hi Res Spectrometer - Infrared --- 2.03 - 5.03 Spectral resolution: Mapping Spectrometer - Visible --- 100 - 380 Mapping Spectrometer - Infrared --- 70 - 360 Hi Res Spectrometer - Infrared --- 1300 - 3000 Field of view (mrad x mrad) Mapping Spectrometer - Visible --- 64 (slit) x 64 (scan) Mapping Spectrometer - Infrared --- 64 (slit) x 64 (scan) Hi Res Spectrometer - Infrared --- 0.583 x 1.749 Mass (kg) 30 Mounting Alignment -------------------------------------------------------- Refer to the latest version of the Rosetta Frames Definition Kernel (FK) [4] for the VIRTIS reference frame definitions and mounting alignment information. Apparent FOV Layout -------------------------------------------------------- WARNING --- the description/diagram below have not been verified This diagram illustrates the VIRTIS-M apparent FOV layout for "zero" scan mirror position in the corresponding reference frame. ^ | direction of | flight | ^ +Xvis (along track) | +Xir | | | ~0.014 degrees | | | v Pixel 1 | Pixel 256 --- +---------|---------+ | 1 line | x-------------> +Yvis (cross track) --- +-------------------+ +Yir ^ 256 pixels/line | | ~3.67 degrees | |<----------------->| | | Boresight (+Z axis) is into the page This diagram illustrates the VIRTIS-M apparent FOV layout resulting from a full, 256 step, +/- 1.83 degree scan mirror sweep about Y axis. ^ | direction of | flight | ^ +Xvis (along track) | +Xir | Pixel 1,1 | --- *---------|---------+ ^ | | | | ~3.67 | | | | degrees | | | | | | | | 256 lines | x-------------> +Yvis (cross track) | (each for | | +Yir | a step in | | | scan seq.)| | V | | --- +-------------------+ | 256 pixels/line | ~3.67 degrees | |<----------------->| | | Boresight (+Z axis) is into the page This diagram illustrates the VIRTIS-H apparent FOV layout in the corresponding reference frame. ^ | direction of | flight | ^ +Xh (along track) | | | | ~0.1 degrees | v | --- Line 1 +-|-+ | | | | | | x-------------> +Yh (cross track) | | | --- Line 3 +---+ ^ 1 pixel/line | | | ~0.0334 degrees ->|---|<----- | | Boresight (+Z axis) is into the page Optical Parameters -------------------------------------------------------- The following VIRTIS-M VIS and IR and VIRTIS-H nominal first order optical parameters are included in the data section below, from [3]: ----------------------------------------------------------------- parameter VIRTIS-M/VIS VIRTIS-M/IR VIRTIS-H ----------------------------------------------------------------- Focal Length, mm 152.0 152.0 195.5 (*) f/ratio f/5.6 f/3.2 f/2.04 IFOV, rad/pixel Cross-track 0.00025 0.00025 0.000583 Along-track 0.00025 0.00025 0.000583 Field of view (deg) Cross-track 3.6669 3.6669 0.0334 Along-track 0.0143 0.0143 0.1002 Field of view (deg) - scan Cross-track 3.6669 3.6669 n/a Along-track 3.6669 3.6669 n/a ----------------------------------------------------------------- (*) VIRTIS-H focal length was estimated from IFOV and pixel size. The keywords below provide nominal values from the table above. Angular size values in the keywords are given radians, with the cross-track size being the first value and the along-track size being the second value in each pair. \begindata INS-226211_FOCAL_LENGTH = ( 152.0 ) INS-226211_F/RATIO = ( 5.6 ) INS-226211_FOV_ANGULAR_SIZE = ( 0.064000, 0.000250 ) INS-226211_IFOV = ( 0.000250, 0.000250 ) INS-226213_FOCAL_LENGTH = ( 152.0 ) INS-226213_F/RATIO = ( 3.2 ) INS-226213_FOV_ANGULAR_SIZE = ( 0.064000, 0.000250 ) INS-226213_IFOV = ( 0.000250, 0.000250 ) INS-226220_FOCAL_LENGTH = ( 195.5 ) INS-226220_F/RATIO = ( 2.04 ) INS-226220_FOV_ANGULAR_SIZE = ( 0.000583, 0.001749 ) INS-226220_IFOV = ( 0.000583, 0.000583 ) \begintext Detector Parameters -------------------------------------------------------- The nominal VIRTIS detector parameters from [6] are: ----------------------------------------------------------------- parameter VIRTIS-M/VIS VIRTIS-M/IR VIRTIS-H ----------------------------------------------------------------- Detector Array Size/Physical Cross-track 512 270 436 Along-track 1024 436 270 Detector Array Size/Spatial Cross-track 256 (1) 256 (2) 1 Along-track 1 1 3 Detector Array Center/Spatial Cross-track 127.5 127.5 0.5 Along-track 0.5 0.5 1.5 Pixel Size, microns/Spatial Cross-track 38 (3) 38 38 Along-track 38 38 38 ----------------------------------------------------------------- (1) VIS CCD pixels are 2x2 binned at detector level (2) assuming IR reads out the same number of pixels as VIS (3) size of a 2x2 binned pixel The values are given in microns for PIXEL_SIZE keywords and in counts for PIXEL_SAMPLES, PIXEL_LINES, and CENTER keywords. \begindata INS-226211_PIXEL_SIZE = ( 38, 38 ) INS-226211_PIXEL_SAMPLES = ( 256 ) INS-226211_PIXEL_LINES = ( 1 ) INS-226211_CCD_CENTER = ( 127.5, 0.5 ) INS-226213_PIXEL_SIZE = ( 38, 38 ) INS-226213_PIXEL_SAMPLES = ( 256 ) INS-226213_PIXEL_LINES = ( 1 ) INS-226213_CCD_CENTER = ( 127.5, 0.5 ) INS-226220_PIXEL_SIZE = ( 38, 38 ) INS-226220_PIXEL_SAMPLES = ( 1 ) INS-226220_PIXEL_LINES = ( 3 ) INS-226220_CCD_CENTER = ( 0.5, 1.5 ) \begintext FOV Definitions --------------------------------------------------------------------------- This section contains definitions for the VIRTIS FOVs. These definitions are provided in the format required by the SPICE (CSPICE) function GETFOV (getfov_c). The set of assignments in the data section below defines the VIRTIS-M VIS and IR non-scanning FOVs and VIRTIS-H FOV with respect to the corresponding frames to be a rectangles with the corners defined by the first and last pixels of the spatial, cross-track line and the boresight along the +Z axis. These FOV definitions use angular extent style specification with the cross and along track angular sizes taken from the ``Optics Parameters'' section above. \begindata INS-226211_FOV_FRAME = 'ROS_VIRTIS-M_VIS' INS-226211_FOV_SHAPE = 'RECTANGLE' INS-226211_BORESIGHT = ( 0.000000 0.000000 152.000000 ) INS-226211_FOV_CLASS_SPEC = 'ANGLES' INS-226211_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-226211_FOV_REF_ANGLE = ( 0.00716197 ) INS-226211_FOV_CROSS_ANGLE = ( 1.83346494 ) INS-226211_FOV_ANGLE_UNITS = 'DEGREES' INS-226213_FOV_FRAME = 'ROS_VIRTIS-M_IR' INS-226213_FOV_SHAPE = 'RECTANGLE' INS-226213_BORESIGHT = ( 0.000000 0.000000 152.000000 ) INS-226213_FOV_CLASS_SPEC = 'ANGLES' INS-226213_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-226213_FOV_REF_ANGLE = ( 0.00716197 ) INS-226213_FOV_CROSS_ANGLE = ( 1.83346494 ) INS-226213_FOV_ANGLE_UNITS = 'DEGREES' INS-226220_FOV_FRAME = 'ROS_VIRTIS-H' INS-226220_FOV_SHAPE = 'RECTANGLE' INS-226220_BORESIGHT = ( 0.000000 0.000000 195.500000 ) INS-226220_FOV_CLASS_SPEC = 'ANGLES' INS-226220_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-226220_FOV_REF_ANGLE = ( 0.01670172 ) INS-226220_FOV_CROSS_ANGLE = ( 0.05010516 ) INS-226220_FOV_ANGLE_UNITS = 'DEGREES' \begintext The set of assignments in the data section below defines the VIRTIS-M VIS and IR apparent FOVs resulting from a full, 256 step, +/- 1.83 degree scan mirror sweep about Y axis with respect to the corresponding frames to be a rectangles with the corners defined by the first and last pixels of the spatial, cross-track line in the first and last scan positions and the boresight along the +Z axis. These FOV definitions use angular extent style specification with the cross and along track angular sizes taken from the ``Optics Parameters'' section above. \begindata INS-226212_FOV_FRAME = 'ROS_VIRTIS-M_VIS' INS-226212_FOV_SHAPE = 'RECTANGLE' INS-226212_BORESIGHT = ( 0.000000 0.000000 152.000000 ) INS-226212_FOV_CLASS_SPEC = 'ANGLES' INS-226212_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-226212_FOV_REF_ANGLE = ( 1.83346494 ) INS-226212_FOV_CROSS_ANGLE = ( 1.83346494 ) INS-226212_FOV_ANGLE_UNITS = 'DEGREES' INS-226214_FOV_FRAME = 'ROS_VIRTIS-M_IR' INS-226214_FOV_SHAPE = 'RECTANGLE' INS-226214_BORESIGHT = ( 0.000000 0.000000 152.000000 ) INS-226214_FOV_CLASS_SPEC = 'ANGLES' INS-226214_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-226214_FOV_REF_ANGLE = ( 1.83346494 ) INS-226214_FOV_CROSS_ANGLE = ( 1.83346494 ) INS-226214_FOV_ANGLE_UNITS = 'DEGREES' \begintext Optical Distortion -------------------------------------------------------- [TBD] Platform ID --------------------------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the instrument mounted. All VIRTIS components it is the spacecraft. \begindata INS-226200_PLATFORM_ID = ( -226000 ) INS-226210_PLATFORM_ID = ( -226000 ) INS-226211_PLATFORM_ID = ( -226000 ) INS-226213_PLATFORM_ID = ( -226000 ) INS-226220_PLATFORM_ID = ( -226000 ) \begintext