KPL/IK ORX OLA Instrument Kernel =============================================================================== This Instrument Kernel (IK) file contains Field-Of-View (FOV) and other geometric parameters definitions for the OSIRIS-REx Laser Altimeter (OLA) instrument. Version and Date ------------------------------------------------------------------------------- Version 0.1 -- July 27, 2018 -- Boris Semenov, NAIF Updated based on [4]. Version 0.0 -- August 24, 2015 -- Boris Semenov, NAIF Placeholder version. References ------------------------------------------------------------------------------- 1. Kernel Pool Required Reading 2. GETFOV, getfoc_c, cspice_getfov headers 3. ORX FK file, latest version 4.``Summary of Spice Kernel Changes.docx'', Michael Daly, York University, 04/20/2018 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 kernel must ``load'' the kernel, normally during program initialization. The SPICE routine FURNSH loads a kernel file into the pool as shown below. CALL FURNSH ( 'frame_kernel_name; ) -- FORTRAN furnsh_c ( "frame_kernel_name" ); -- C cspice_furnsh, frame_kernel_name -- IDL cspice_furnsh( 'frame_kernel_name' ) -- MATLAB Once the file has been loaded, the SPICE routine GETFOV (getfov_c in C, cspice_getfov in IDL and MATLAB) can be used to retrieve FOV parameters for a given instrument or structure. This file was created and may be updated with a text editor or word processor. Naming Conventions ---------------------------------------------------------- All names referencing values in this IK file start with the characters `INS' followed by the NAIF ORX ID number (-64) followed by a NAIF three digit ID code for one of OLA detectors: ORX_OLA_HIGH -64402 ORX_OLA_LOW -64403 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the boresight direction of ORX_OLA_HIGH is specified by: INS-64402_BORESIGHT The upper bound on the length of the name of any data item is 32 characters. If the same item is included in more than one file, or if the same item appears more than once within a single file, the latest value supersedes any earlier values. Instrument Description --------------------------------------------------------- OLA is a scanning laser altimeter with two laser transmitters and a common receiver. The scanning is in two dimensions and configurable as spot, line and raster patterns. It measures at two rates with the lower rate having greater range capability than the higher rate (100Hz and 10 kHz). Further details may be found in Daly, M.G., Barnouin, O.S., Dickinson, C. et al. Space Sci Rev (2017) 212: 899. https://doi.org/10.1007/s11214-017-0375-3 Mounting Alignment -------------------------------------------------------- Refer to the latest version of the ORX Frames Definition Kernel (FK) [3] for the instrument reference frame definitions and mounting alignment information. Instrument Detector/Sensor Layout ---------------------------------------------------------- OLA approximates a mono-axial lidar. Instrument Pixel-to-3D Coordinate Mapping ---------------------------------------------------------- The laser transmitter pointing is assessed using azimuth and elevation angles from the scanning mirror that coincide with the spacecraft X and Y axes. Along with the measurement direction, a range and a measurement time is provided. The measurement times, ranges and angles require correction based on a ground calibration file. The time correction consists of a set of computations to correct OLA time to spacecraft time. The range correction to the mirror articulation origin requires the subtraction of a fixed offset. Angular corrections require an angular correction for each of the azimuth and elevation direction that are dependent on the measured values in both directions. Instrument Detector/Sensor Parameters ---------------------------------------------------------- N/A. Instrument Optical Parameters ---------------------------------------------------------- The instrument’s sampled area is determined by the laser beam divergences of the two transmitters. These are identified as instrument FOVs below. Instrument Optical Distortion ---------------------------------------------------------- N/A. Instrument Filter Parameters ---------------------------------------------------------- N/A. Instrument FOV Definition(s) ---------------------------------------------------------- This section defines the following FOVs: ID SHAPE FRAME SIZE BSIGHT SOURCE ------- -------- ------------- -------- ------ ------------- -64402 CIRCLE ORX_OLA_HIGH 0.00550 +Z Daly, April 2018 -64403 CIRCLE ORX_OLA_LOW 0.00249 +Z Daly, April 2018 where the source means: Daly -- Based on acceptance test data. All sizes are half-extents given in degrees. FOVs are actually laser beam divergences that are 1/e values. The FOVs are defined in this data block. \begindata INS-64402_FOV_CLASS_SPEC = 'ANGLES' INS-64402_FOV_SHAPE = 'CIRCLE' INS-64402_FOV_FRAME = 'ORX_OLA_HIGH' INS-64402_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-64402_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-64402_FOV_REF_ANGLE = ( 0.00550 ) INS-64402_FOV_ANGLE_UNITS = ( 'DEGREES' ) INS-64403_FOV_CLASS_SPEC = 'ANGLES' INS-64403_FOV_SHAPE = 'CIRCLE' INS-64403_FOV_FRAME = 'ORX_OLA_LOW' INS-64403_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-64403_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-64403_FOV_REF_ANGLE = ( 0.00249 ) INS-64403_FOV_ANGLE_UNITS = ( 'DEGREES' ) \begintext End of the IK file.