KPL/IK THEMIS Instrument kernel =========================================================================== This instrument kernel (I-kernel) contains the Mars Odyssey 2001 Thermal Emission Imaging System (THEMIS) optics, detector and filter parameters. Version and Date --------------------------------------------------------------------------- Version 1.1 -- August 1, 2001 -- Boris Semenov, NAIF/JPL Updated the active IR detector pixel size with values provided by Greg Mehall. Version 1.0 -- July 30, 2001 -- Boris Semenov, NAIF/JPL Included description and parameter values provided by Greg Mehall. Version 0.1 -- March 12, 2001 -- Boris Semenov, NAIF/JPL Pre-release. Added IR and VIS FOV definitions based on nominal FOV angular sizes. Version 0.0 -- March 5, 2001 -- Boris Semenov, NAIF/JPL Pre-release. References --------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. ``C-kernel Required Reading'' 3. ``THEMIS ICD'', MSP01-97-0008, June 10, 1999 4. M'01 Frames Definition Kernel (FK), latest version. 5. THEMIS Instrument Characteristics, ASU THEMIS Team Web Site, http://emma.la.asu.edu/THEMIS/inst.html, March 2001. 6. THEMIS Information Sheet, JPL M'01 Odyssey Web Site, http://mars.jpl.nasa.gov/2001/instruments/images/themis1.jpg, March 2001. 7. Corrections and additions by Greg Mehall, July 2001. Implementation Notes -------------------------------------------------------- User programs that need I-kernel data must `load' the I-kernel file, normally during program initialization. Loading the kernel using SPICELIB routine LDPOOL causes the data items and their associated values present in the kernel to become associated with a data structure called the ``kernel pool''. Then a user's program can obtain the value(s) for any data item using the SPICELIB routines GDPOOL, GIPOOL and GCPOOL. See [1] for details. This file was created and can 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 M'01 spacecraft ID number (-53) followed by the NAIF three digit THEMIS IR instrument reference number (031) or THEMIS VIS instrument reference number (032). The remainder of the name is an underscore character followed by the unique name of the data item. For example, the focal length of the THEMIS IR camera is specified by INS-53031_FOCAL_LENGTH The upper bound on the length of the name of any data item is 32 characters. If the same item is included in more then one file, or if the same item appears more than once within a single file, the latest value supersedes any earlier values. THEMIS Overview -------------------------------------------------------- From [5] & [7]: "Infrared Imaging by THEMIS -------------------------- The Thermal Emission Imaging System (THEMIS) will determine the mineralogy and petrology of the Martian surface using a multi-spectral, thermal infrared images with 10 spectral filters filters between 6.6 and 15.0 micrometers. The 9 infrared spectral filters were selected in part based on the mineral results from the Mars Global Surveyor Thermal Emission Spectrometer (TES). The THEMIS infrared camera utilizes an uncooled 240 x 320 pixel microbolometer detector array. The array readout rate is 30 frames per second. The detector array is divided into ten 24 x 320 pixel "data" bands. The infrared camera also uses "time delayed integration" (TDI) to increase the signal to noise for each band. This is accomplished by summing the data from 16 of each 24 active rows in each data band. Any combination of the 10 data bands can be selected and downlinked for each infrared image. The resultant downlinked data is a 1 x 320 pixel line at a rate of 30 lines per second for each selected data band. The TDI can be disabled but will result in the reduction of the signal to noise by a factor of four. When TDI is disabled, only the data from 1 of each 24 active rows in each data band is downlinked The 9 spectral optical filters are attached to the front of the detector array. The 6.6 microns spectral filter covers 2 data bands (48 x 320 pixels) and the remaining spectral filters cover 1 data band (24 x 320 pixels). Each spectral filter has a full-width half-maximum bandwidth of approximately 1 microns. The instantaneous field of view of each infrared pixel is 250 microrad. The resulting cross-track field of view is 80 mrad. The image length is selectable in increments of 64 mrad allowing the along-track field of view to vary from 68 to 16324 mrad. From a 400 km mapping orbit, the entire planet will be mapped in the infrared with a ground sampling distance of 100 meters. At this altitude, the image cross-track width will be 32 km and the image along-track length can vary from 27 to 6530 km. Visible Imaging by THEMIS ------------------------- The THEMIS will study small-scale geologic processes on the Martian surface using a multi-spectral, visible images with 5 spectral filters between 420 and 870 nanometers. The THEMIS visible camera utilizes a 1024 x 1024 pixel CCD. The array integration time is selectable with a nominal setting of 6 milliseconds for Martian mapping operations. The array inter-frame time is also selectable with a nominal setting of 1 second. The detector array is divided into five 1024 x 192 pixel data bands. Any combination of these 5 bands can be selected and downlinked for each visible image. The resultant downlinked data is a 1024 x 192 pixel frame at a rate of one frame per second for each selected band. The visible camera also allows for 2x and 4x pixel spatial summing to reduce data volume. The 5 spectral optical filters are attached to the front of the CCD. Each filter covers approximately 1024 x 204 pixels on the CCD and includes the 1024 x 192 pixels of the data band. Each spectral filter has a full-width half-maximum bandwidth of approximately 50 nanometers. The instantaneous field of view of each visible pixel is 45 microrad. The resulting cross-track field of view is 46.08 mrad. The image length is selectable in increments of 192 line frames. Based on the nominal interframe time of 1 sec, the corresponding incremental along-track field of view is 7.5 mrad. The data volume for each visible image is also limited to the 3,915,776 byte internal buffer in the visible camera electronics. From a 400 km mapping orbit, the planet will be mapped in the visible with a ground sampling distance of 18 meters. At this altitude, the image cross-track width will be 18.4 km and the image along-track length can vary from 3.5 to 9 km for 5 band images and from 3.5 to 57 km for single band images. Use of spatial summing will allow longer image lengths with reduced spatial resolution. The THEMIS instrument was designed and built by Arizona State University, Tempe, Arizona, and Raytheon, Santa Barbara Remote Sensing, Goleta California. The visible camera sub-system and flight software development were provided by Malin Space Science Systems, San Diego, California. The THEMIS will be controlled and operated from the mission operations facility at Arizona State University, Tempe, Arizona." THEMIS Mounting Alignment -------------------------------------------------------- Refer to the latest version of Mars Odyssey 2001 Frames Definition Kernel ([4]) for the THEMIS frame definitions and mounting alignment information. THEMIS Optics Parameters -------------------------------------------------------- The following THEMIS IR and VIS first order optical parameters are included in the data section below ([6]&[7]): ----------------------------------------------------------------- parameter IR VIS ----------------------------------------------------------------- Focal Length, mm 200.0 200.0 f/ratio f/1.66 f/1.66 IFOV, rad/pixel 0.000250 0.000045 Field of view (rad) Cross-track 0.080 0.04608 Along-track 0.060 0.04608 ----------------------------------------------------------------- The values in the keywords are given in the same units as in the table. \begindata INS-53031_FOCAL_LENGTH = ( 200.0 ) INS-53031_F/RATIO = ( 1.667 ) INS-53031_FOV_ANGULAR_SIZE = ( 0.080, 0.060 ) INS-53031_IFOV = ( 0.000250 ) INS-53032_FOCAL_LENGTH = ( 200.0 ) INS-53032_F/RATIO = ( 1.667 ) INS-53032_FOV_ANGULAR_SIZE = ( 0.04608, 0.04608 ) INS-53032_IFOV = ( 0.000045 ) \begintext THEMIS FOV Definitions --------------------------------------------------------------------------- Both FOVs defined in this section are based on the nominal THEMIS detector FOV angular sizes provided in the Table in "THEMIS Optics Parameters" section above. The set of keywords in the data section below defines nominal THEMIS IR FOV with respect to the M01_THEMIS_IR frame to be a rectangle with angular sizes of 0.080 radians in M01_THEMIS_IR XZ-plane (plane parallel to the IR CCD lines and, nominally, normal to the mapping orbit plane) and 0.060 radians in M01_THEMIS_IR YZ-plane (normal to the IR CCD columns and, nominally, parallel to the mapping orbit plane) with the boresight along +Z axis of M01_THEMIS_IR frame. \begindata INS-53031_FOV_FRAME = 'M01_THEMIS_IR' INS-53031_FOV_SHAPE = 'RECTANGLE' INS-53031_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-53031_FOV_BOUNDARY_CORNERS = ( +0.0399713690821580 +0.0299715285563850 +0.9987512188376500 -0.0399713690821580 +0.0299715285563850 +0.9987512188376500 -0.0399713690821580 -0.0299715285563850 +0.9987512188376500 +0.0399713690821580 -0.0299715285563850 +0.9987512188376500 ) \begintext The set of keywords in the data section below defines nominal THEMIS VIS FOV with respect to the M01_THEMIS_VIS frame to be a rectangle with angular sizes of 0.04608 radians in M01_THEMIS_VIS XZ-plane (plane parallel to the VIS CCD lines and, nominally, normal to the mapping orbit plane) and 0.04608 radians in M01_THEMIS_VIS YZ-plane (normal to the VIS CCD columns and, nominally, parallel to the mapping orbit plane) with the boresight along +Z axis of M01_THEMIS_VIS frame. \begindata INS-53032_FOV_FRAME = 'M01_THEMIS_VIS' INS-53032_FOV_SHAPE = 'RECTANGLE' INS-53032_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-53032_FOV_BOUNDARY_CORNERS = ( +0.0230318503829290 +0.0230318503829290 +0.9994693930961000 -0.0230318503829290 +0.0230318503829290 +0.9994693930961000 -0.0230318503829290 -0.0230318503829290 +0.9994693930961000 +0.0230318503829290 -0.0230318503829290 +0.9994693930961000 ) \begintext THEMIS Optical Distortion Specification -------------------------------------------------------- The optical distortion for IR for VIS camera was not available at the time when this version of the IK was released. THEMIS Detector Parameters -------------------------------------------------------- The following THEMIS IR and VIS detector geometry parameters are included in the data section below ([6]&[7]): ----------------------------------------------------------------- parameter IR VIS ----------------------------------------------------------------- Pixel Size, microns Physical Cross-track 50 9.0 Along-track 50 9.0 Active Cross-track 45.4 2.6 Along-track 24.6 6.2 Detector Array Size (physical) Cross-track 320 1024 Along-track 240 1024 Detector Array Center (physical) Cross-track 160.5 512.5 Along-track 120.5 512.5 Detector Array Size (Active) Cross-track 320 1008 Along-track 240 1018 Detector Array Center (Active) Cross-track 160.5 504.5 Along-track 120.5 509.5 ----------------------------------------------------------------- The values in the keywords are given in the same units as in the table above. \begindata INS-53031_PIXEL_SIZE = ( 50, 50 ) INS-53031_PIXEL_SAMPLES = ( 320 ) INS-53031_PIXEL_LINES = ( 240 ) INS-53031_CENTER = ( 160.5, 120.5 ) INS-53032_PIXEL_SIZE = ( 9, 9 ) INS-53032_PIXEL_SAMPLES = ( 1008 ) INS-53032_PIXEL_LINES = ( 1018 ) INS-53032_CENTER = ( 504.5, 509.5 ) \begintext Relationship Between THEMIS Frames and Detector Line/Sample Coordinates --------------------------------------------------------------------------- This section provides the location of the pixel (1,1) of the IR and VIS cameras with respect to the corresponding camera frames. IR Pixel (1,1) Direction The first pixel in the first row of the IR images is in the fore-track S/C +Y direction and in the cross-track S/C +Z direction or in the +X/+Y quadrant of the M01_THEMIS_IR frame: ^ +Yir -- s/c velocity/along track | Pixel | (1,1)-------|---------+ | | | | | | | | | | | | <-------------x | 240 rows +Xir | +Zir | cross-track | boresight | | (into page) | | | +-------------------+ 320 samples/row VIS Pixel (1,1) Direction The first pixel in the first row of the VIS images is in the fore-track S/C +Y direction and in the cross-track S/C +Z direction or in the +X/+Y quadrant of the M01_THEMIS_VIS frame: ^ +Yvis -- s/c velocity/along track | Pixel | (1,1)-------|---------+ | | | | | | | | | | | | <-------------x | 1018 rows +Xvis | +Zvis | cross-track | boresight | | (into page) | | | +-------------------+ 1008 samples/row Filters --------------------------------------------------------------------------- IR Filters The AR coated ZeSe window and multi-layer thin-film Ge filters comprise the spectral separation for the nine THEMIS infrared filters. Filters cover all 320 pixels in the cross-track S/C z-axis direction. Filter 1 (6.6 microns band) is in the fore-track S/C +y direction. Each filter covers approximately 20 rows on the array but only 16 rows of optically clear pixels are used. Dark mirror coating covers the rows between each filter. ----------------------------------------------------------------- Filter # Band Center, Bandwidth, Start End microns microns Row Row ----------------------------------------------------------------- 1 6.62 1.01 1 32 2 7.88 1.09 43 58 3 8.56 1.18 69 84 4 9.30 1.18 95 110 5 10.11 1.10 121 136 6 11.03 1.19 147 162 7 11.78 1.07 173 188 8 12.58 0.81 198 213 9 14.96 0.86 224 239 ----------------------------------------------------------------- The IR filter layout summarized in the table looks like this: ^ Row Index | s/c velocity --------- | 1 (*)----------------------------------------------+ | | | IR Filter 1 | 32 rows | | 32 +-----------------------------------------------+ 43 +---------------------------------(10 dark rows)+ | IR Filter 2 | 16 rows 58 +-----------------------------------------------+ 69 +---------------------------------(10 dark rows)+ 2 | IR Filter 3 | 16 rows 4 84 +-------------- +Yir ----------------+ 0 95 +-------------- ^ --(10 dark rows)+ | IR Filter 4 | | 16 rows r 110 +-------------- | ----------------+ o 121 +-------------- <---- x --(10 dark rows)+ w | IR Filter 5 +Xir +Zir | 16 rows s 136 +-------------- (into ----------------+ 147 +-------------- page) --(10 dark rows)+ | IR Filter 6 | 16 rows 162 +-----------------------------------------------+ 173 +---------------------------------(10 dark rows)+ | IR Filter 7 | 16 rows 188 +-----------------------------------------------+ 198 +----------------------------------(9 dark rows)+ | IR Filter 8 | 16 rows 213 +-----------------------------------------------+ 224 +---------------------------------(10 dark rows)+ | IR Filter 9 | 16 rows 239 +-----------------------------------------------+ (1 dark row) 320 samples The set of keywords below contains wavelength center, bandwidth and CCD row ranges for each IR filter. \begindata INS-53031_FILTER_BANDCENTER = ( 6.62, 7.88, 8.56, 9.30, 10.11, 11.03, 11.78, 12.58, 14.96 ) INS-53031_FILTER_BANDWIDTH = ( 1.01, 1.09, 1.18, 1.18, 1.10, 1.19, 1.07, 0.81, 0.86 ) INS-53031_FILTER_FIRST_ROW = ( 1, 43, 69, 95, 121, 147, 173, 198, 224 ) INS-53031_FILTER_LAST_ROW = ( 32, 58, 84, 110, 136, 162, 188, 213, 239 ) \begintext VIS Filters Five color filters are cemented onto the visible detector surface with the gaps between filters aligned with the detector rows. For non-calibration images, the camera firmware skips the dark rows and the gaps between filters, producing 192 lines per filter in the 1x1 summing mode. A special calibration image capability can be used to read out all rows, 1x1 summing only. Filters cover all 1024 pixels in the cross track S/C z-axis direction. Filter 1 (0.870 microns band) is in the fore-track S/C +y direction. Each filter covers approximately 205 rows on the array but only the 192 rows of optically clear pixels are used. There are no dark mirror coatings over the rows between each filter. ----------------------------------------------------------------- Filter # Band Center, Bandwidth, Start End microns microns Row Row ----------------------------------------------------------------- 1 0.870 0.049 4 195 2 0.423 0.051 203 394 3 0.652 0.053 404 595 4 0.751 0.053 612 803 5 0.553 0.045 814 1005 ----------------------------------------------------------------- The VIS filter layout summarized in the table looks like this: ^ Row Index | s/c velocity --------- | (3 dark rows) 4 (*)----------------------------------------------+ | | | VIS Filter 1 | 192 rows | | 195 +-----------------------------------------------+ 203 +----------------------------------(7 dark rows)+ | | | VIS Filter 2 | 192 rows | +Yvis | 1 394 +--------------- ^ ----------------+ 0 404 +--------------- | ---(9 dark rows)+ 1 | | | 8 | VIS Filter 3 <----x | 192 rows | +Xvis +Zvis | r 595 +-------------- ----------------+ o 612 +-------------- --(16 dark rows)+ w | | s | VIS Filter 4 | 192 rows | | 803 +-----------------------------------------------+ 814 +---------------------------------(10 dark rows)+ | | | VIS Filter 5 | 192 rows | | 1005 +-----------------------------------------------+ (13 dark rows) 1008 samples The set of keywords below contains wavelength center, bandwidth and CCD row ranges for each VIS filter. \begindata INS-53032_FILTER_BANDCENTER = ( 0.870, 0.423, 0.652, 0.751, 0.553 ) INS-53032_FILTER_BANDWIDTH = ( 0.049, 0.051, 0.053, 0.053, 0.045 ) INS-53032_FILTER_FIRST_ROW = ( 4, 203, 404, 612, 814 ) INS-53032_FILTER_LAST_ROW = ( 195, 394, 595, 803, 1005 ) \begintext Platform ID --------------------------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the cameras are mounted. For both THEMIS detectors such platform is the spacecraft itself. \begindata INS-53031_PLATFORM_ID = ( -53000 ) INS-53032_PLATFORM_ID = ( -53000 ) \begintext