KPL/IK DECA Instrument kernel =========================================================================== This instrument kernel (I-kernel) contains the ExoMars-2016 Schiaparelli Entry, Descent and Landing Demonstrator Module (EDM) Descent Camera (DECA) optics, detector, and field-of-view (FOV) parameters. Version and Date --------------------------------------------------------------------------- Version 0.0 -- September 20, 2016 -- Marc Costa Sitja, ESAC/ESA Initial Release. Pending review by the ExoMars 2016 EDM Project Team at ESTEC. References --------------------------------------------------------------------------- 1. ``Frames Required Reading'' 2. ``Kernel Pool Required Reading'' 3. ``C-kernel Required Reading'' 4. ExoMars-2016 EDM Frames Definition Kernel (FK), latest version. 5. ``DECA User Manual'', EXM-DECA-UM-RSSD-0001, Issue 2, Revision 5, 28 July, 2014. Contact Information --------------------------------------------------------------------------- If you have any questions regarding this file contact SPICE support at ESAC: Marc Costa Sitja (+34) 91-8131-457 mcosta@sciops.esa.int, esa_spice@sciops.esa.int or NAIF at JPL: Boris Semenov (818) 354-8136 Boris.Semenov@jpl.nasa.gov Implementation Notes -------------------------------------------------------- Applications that need SPICE I-kernel data must ``load'' the I-kernel file, 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 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''. 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. The application program may obtain the value(s) for any other IK data item using the SPICELIB routines GDPOOL, GIPOOL, GCPOOL (gdpool_c, gipool_c, gcpool_c in C, cspice_gdpool, cspice_gipool, cspice_gcpool in IDL and MATLAB). See [2] for details. This file was created with, and can be updated with a text editor or word processor. Naming Conventions and Conventions for Specifying Data -------------------------------------------------------- Data items are specified using ``keyword=value'' assignments [2]. All keywords referencing values in this I-kernel start with the characters `INS' followed by the NAIF EDM instrument ID code, constructed using the spacecraft ID number (-117) followed by the NAIF three digit ID number for DECA camera (100): Instrument name ID -------------------- ------- EDM_DECA -117100 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the DECA camera boresight direction in the EDM_DECA frame is specified by: INS-117100_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 -------------------------------------------------------- DECA - the 'Descent Camera' - is a re-flight of an instrument called VMC (Visual Monitoring Camera), which flew on the Herschel-Planck mission. The camera was designed and built by the company OIP. An Engineering and Qualification Model (EQM) and a Flight Spare (FM2) were delivered to ESA/ESTEC and have been on storage there, while the FM1 was delivered and flew on Herschel. In 2011, it was decided that the Flight Spare would be considered to fly on the 2016 EDL Demonstrator Module (EDM) to obtain some images during the descent. The hardware was not modified at all apart from mounting new labels. A delta-qualification campaign was performed to ensure that the camera will be suited for a landing on Mars. The DECA instrument is a camera which uses a STAR-1000 detector. It is read out with 8 bit dynamic range. Only the center 512 x 512 px2 are used. DECA has a lens with a field of view of 60 x 60 deg2. DECA is mounted downward-looking, pointing 20° off-nadir. It will be starting to acquire images a certain time after front-shield jettisoning. After switch-on, it will wait for 5 seconds, then acquire 15 images spaced by 1.5 seconds. The data will be stored in local memory. Several minutes after the landing of the EDM on the surface (to avoid electrostatic discharges affecting the instrument) the data will be read out by the EDM computer (CTPU) and subsequently downlinked to Earth. There are several scientific goals that will be addressed by DECA: (a) Transparency of the atmosphere. The total duration of the image sequence will be 21 seconds. In this time, the EDM will drop a significant altitude through the atmosphere. By comparing the contrast in the images, it is possible to constrain the dust content of the atmosphere. (b) High-resolution imaging of the landing site. The camera is fixed-mounted on the EDM platform, looking downward. The rotation and swinging of the EDM under its parachute will point the camera in different downward directions. Due to the proximity to the Mars surface, very high-resolution images can be obtained which will allow constraining the position of the landing site. (c) 3-D topography - with simple 'shape from shading' routines, a 3-D model of the imaged surface can be approximated. Optical Parameters -------------------------------------------------------- [TBD] Mounting Alignment -------------------------------------------------------- Refer to the latest version of the EDM Frames Definition Kernel (FK) [3] for the DECA reference frame definitions and mounting alignment information. DECA Camera Field-of-View Layout -------------------------------------------------------- The DECA camera comprises a single square CCD detector. The view directions of the corners and the axes of the EDM_DECA frame projected onto the Mars surface look like this: (512,512) Pixel +----------------------+ --------- | | ^ | +Ydeca | | | boresight | | | (out of the page) | | <-----------------o | 60.0 deg +Zdeca | | | | | | | | | | | | | | | v +-----------|----------+ ---------- (1,1) v Pixel +Xdeca | | |<-------------------->| 60.0 deg FOV Definition --------------------------------------------------------------------------- This section contains definitions for the DECA camera FOV. These definitions are provided in a format consistent required by the SPICE (CSPICE, ICY) function GETFOV (getfov_c, cspice_getfov). The set of assignments in the data section below defines the DECA FOV with respect to the EDM_DECA frame to be a rectangle with the corners defined by the first and last pixels of the first and last lines of the CCD and the boresight along the +Y axis of the EDM_DECA frame. This FOV definition uses angular extent style specification with the cross and along track angular sizes taken from the ``Optics Parameterss'' section above. The reference vector has been selected such the boundary vector returned from the function GETFOV (getfov_c, cspice_getfov) corresponds to pixel (1,1) as described in the ``Detector Layout'' section above. The following vectors returned from the function correspond to the corner points of the detector layout counted clockwise from (1,1). Please note that the FOV reference and cross angles are defined with half angle values. \begindata INS-117100_FOV_FRAME = 'EDM_DECA' INS-117100_FOV_SHAPE = 'RECTANGLE' INS-117100_BORESIGHT = ( 0.0 1.0 0.0 ) INS-117100_FOV_CLASS_SPEC = 'ANGLES' INS-117100_FOV_REF_VECTOR = ( 1.0 0.0 0.0 ) INS-117100_FOV_REF_ANGLE = ( 30.0 ) INS-117100_FOV_CROSS_ANGLE = ( 30.0 ) INS-117100_FOV_ANGLE_UNITS = 'DEGREES' \begintext Platform ID --------------------------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the camera is mounted. For the DECA camera this platform is the spacecraft. \begindata INS-117100_PLATFORM_ID = ( -117000 ) \begintext End of IK file.