Thermal Emission Imaging System
2001 Mars Odyssey
THEMIS STANDARD DATA PRODUCTS SOFTWARE INTERFACE SPECIFICATION
January 1, 2007
Thermal Emission Imaging System
2001 Mars Odyssey
THEMIS STANDARD DATA PRODUCTS SOFTWARE INTERFACE SPECIFICATION
Prepared by:
Kimberly C. Murray Date
THEMIS Data Archivist
Approved by:
Philip R. Christensen Date
THEMIS Principal Investigator
Greg L. Mehall Date
THEMIS Instrument Manager
Noel S. Gorelick Date
THEMIS Principal Systems Programmer
R. Stephen Saunders Date
Mars Odyssey Project Scientist
Betty J. Sword Date
PDS Mars Data Engineer
January 1, 2007
|
Date |
Description |
Sections affected |
|
10/01/01 |
Initial draft |
All |
|
02/25/02 |
Response to PDS Imaging Node review |
All |
|
04/01/02 |
Response to PDS Imaging Node review; QUBE label corresponds with SFDU2CUBE V-1.45 |
Most |
|
05/31/02 |
Response to PDS Imaging Node review and external content review; QUBE label corresponds with SFDU2CUBE V-1.50 |
Most |
|
07/24/02 |
Revision of TIME keywords
in all labels; revision of IREDR CORE_NULL value; revision of RDR label;
revision of center corresponds of the |
Section 2.3.3; Appendices |
|
10/01/02 |
Revision of IR-RDR QUBEs calibration (V-4.5) and data format; QUBE label corresponds with SFDU2CUBE V-1.54 Response to PDS Peer Review |
Sections 2.2, 3.2; Appendices |
|
01/01/03 |
Addition of IR-BTR and VIS-ABR as Standard Data Products |
Title and most sections |
|
|
Revision of EDR QUBE
headers corresponds with SFDU2CUBE V-1.56; revision of RDR QUBE headers
corresponds with IR calibration V-4.6 and |
Appendices |
|
|
Addition of ERRATA_ID history objects |
Appendix A.6 |
|
04/01/03 |
Revision of IR-RDR QUBE format; revision of VIS-RDR History Object |
Section 3.2; Appendices |
|
07/01/03 |
Revisions to timing keywords corresponds with SFDU2CUBE V-1.59; revision of VIS-RDR History Object |
Section 2.3.4, Appendices |
|
10/01/03 |
Addition of geometry source keyword to BTR and ABR images |
Appendices |
|
10/01/04 |
Complete reference available for THEMIS document [6] |
Section 1.3 |
|
07/01/05 |
Revision of VIS-RDR
History Object |
Appendices A.4 and A.8 |
|
12/01/06 |
Revisions to IR-EDR header
corresponds with SFDU2CUBE V 1.67 |
Section 2.1 and Appendices |
|
01/01/07 |
Revisions to IR-RDR and
BTR headers corresponds to IR calibration V-5.0 |
Appendices |
DOCUMENT CHANGE LOG....................................................................................................... III
CONTENTS.................................................................................................................................. IV
1. INTRODUCTION....................................................................................................................... 1
1.1 Purpose and Scope................................................................................................................. 1
1.2 Contents................................................................................................................................. 1
1.3 Applicable Documents and Constraints.................................................................................... 1
1.4 Relationships with Other Interfaces.......................................................................................... 2
2. Data Product Characteristics and Environment............................................ 2
2.1 Instrument Overview............................................................................................................... 2
2.2 Data Product Overview........................................................................................................... 3
2.3 Standards Used in Generating Data Products........................................................................... 4
2.3.1 PDS Standards................................................................................................................ 4
2.3.2 QUBE Object.................................................................................................................. 4
2.3.3 IMAGE Object................................................................................................................ 6
2.3.4 Time Standards................................................................................................................ 6
2.3.5 Coordinate Systems......................................................................................................... 7
2.3.6 Orbit Numbering Conventions.......................................................................................... 7
2.4 Data Product Contents............................................................................................................ 7
2.4.1 Data Processing Level...................................................................................................... 7
2.4.2 Data Product Generation.................................................................................................. 7
2.4.3 Data Product Archive....................................................................................................... 8
2.4.4 Labeling and Identification................................................................................................ 8
3. Detailed Data Product Specifications................................................................... 9
3.1 Data Product Structure and Organization................................................................................. 9
3.2 Data Format............................................................................................................................ 9
3.3 Labels................................................................................................................................... 10
3.3.1 File Identification and Structure Label............................................................................. 10
3.3.2 HISTORY Object Structure........................................................................................... 10
3.3.3 Telemetry Table Object Structure................................................................................... 11
3.3.4 QUBE Object Label...................................................................................................... 11
3.3.5 IMAGE Object Label.................................................................................................... 11
4. Applicable Software...................................................................................................... 11
4.1 Utility Programs..................................................................................................................... 11
4.2 Applicable PDS Software Tools............................................................................................ 12
A. Appendicies......................................................................................................................... 13
A.1 Example Label: IREDR......................................................................................................... 13
A.2 Example Label: VISEDR...................................................................................................... 15
A.3 Example Label: IRRDR........................................................................................................ 17
A.4 Example Label: VISRDR...................................................................................................... 20
A.5 Example Label: IRBTR......................................................................................................... 22
A.6 Example Label: VISABR...................................................................................................... 22
A.7 Label Keyword Descriptions................................................................................................ 23
A.8 HISTORY Object Items and Examples................................................................................. 33
A.9 Telemetry Table Structure (tlm.fmt)....................................................................................... 36
|
ABR |
Apparent Brightness Record |
|
ASU |
|
|
BTR |
Brightness Temperature Record |
|
DN |
Data Number |
|
EDR |
Experiment Data Record |
|
IR |
Infrared |
|
IRIS |
Infrared Imaging System |
|
IRS |
Infrared Subsystem |
|
|
Integrated Software for Imaging Spectrometers |
|
JPL |
Jet Propulsion Laboratory |
|
NASA |
National Aeronautics and Space Administration |
|
PDS |
Planetary Data System |
|
RDR |
Reduced Data Record |
|
ODY |
2001 Mars Odyssey |
|
SBRS |
|
|
SFDU |
Standard Formatted Data Unit |
|
SIS |
Software Interface Specification |
|
TDI |
Time-Delay Integration |
|
TE |
Thermal Electric |
|
THEMIS |
THermal EMission Imaging System |
|
TLM |
Telemetry |
|
|
Visible |
1. INTRODUCTION
1.1 Purpose and Scope
The purpose of this Data Product SIS is to provide users of the Thermal Emission Imaging System (THEMIS) Visible and Infrared standard data products with enough information to enable them to read and understand the data products. THEMIS standard data products include experimental, reduced, and derived data files. The experimental and reduced products (VISEDR, IREDR, VISRDR, and IRRDR) are spectral image QUBEs consisting of one layer per each visible or infrared band collected. The derived (VISABR and IRBTR) are one band IMAGE files produced from the reduced products. The format and content specifications presented here apply to all data collection phases of the 2001 Mars Odyssey Project for which the data products are available. This SIS is intended to be used by the scientists who will analyze the data, including those associated with the 2001 Mars Odyssey Project and those in the general planetary science community.
1.2 Contents
This Standard Data Product SIS describes in detail how the visible and infrared data products are acquired by the THEMIS instrument, and how the data are processed, formatted, labeled, and uniquely identified. The document discusses standards used in generating the product and the software that may be used to access the product. The data product structure and organization is described in sufficient detail to enable a user to read the product. Finally, examples of product labels are provided.
1.3 Applicable Documents and Constraints
This Data Product SIS is responsive to the following 2001 Mars Odyssey documents:
1. Mars Exploration Program Data Management Plan, R. E. Arvidson and S. Slavney, Rev. 2, Nov. 2, 2000.
2. 2001 Mars Odyssey Orbiter Archive Generation, Validation and Transfer Plan, R. E. Arvidson, R. S. Saunders, and S. Slavney, JPL D-20679, November 3, 2000.
This SIS is also consistent with the following Planetary Data System documents:
3. Planetary Data System Data Preparation Workbook, February 1, 1995, Version 3.1, JPL D-7669, Part 1.
4. Planetary Data System Data Standards Reference, October 30, 2002, Version 3.5, JPL D-7669, Part 2.
5. Planetary Data System Data Dictionary, August 28, 2002, JPL D-7116, Rev E.
(Note: The Data Dictionary is being updated to include several THEMIS specific changes.)
The user is referred to the following THEMIS documents for additional information:
6.
The Thermal Emission Imaging System (THEMIS) for the Mars 2001 Odyssey
7.
Calibration Report for the Thermal Emission Imaging System (THEMIS) for
the 2001 Mars Odyssey
8. Mars Odyssey THEMIS: Data Processing User’s Guide, P.R. Christensen.
9. Mars Odyssey THEMIS: Geometric Processing User’s Guide.
Finally, this SIS is meant to be consistent with the contract negotiated between the 2001 Mars Odyssey Project and the THEMIS Principal Investigator (PI) in which reduced data records and documentation are explicitly defined as deliverable products.
1.4 Relationships with Other Interfaces
Changes in the standard data products (THM-EDR, THM-RDR, IRBTR, or VISABR) would require changes to this document. Changes to the data products will most likely also affect the processing software described in THEMIS Data Processing User’s Guide [8].
2. Data Product Characteristics and Environment
2.1 Instrument Overview
The THEMIS instrument is a combined infrared (IR) and
visible (
THEMIS IR images are acquired at selectable image lengths and in combinations of ten selectable bands. The image width is 320 pixels (32 km, based on the nominal 400 km mapping orbit) and the length is variable, in multiples of 256 line increments, with a minimum and maximum image lengths of 272 and 65,296 lines respectively (27.2 km and 6,530 km, based on the nominal mapping orbit). The IR focal plane is covered by ten ~1 µm-bandwidth strip filters, producing ten band images with bands 1 and 2 having the same wavelength range.
THEMIS VIS images are acquired in framelets of size 1024 pixels crosstrack by 192 lines downtrack, for a total image size of 3.734 Mbytes or less. The number of framelets is determined by the number of bands selected (five available) and the spatial resolution selected (three summing modes available). The size of an image is given by:
[((1024 * 192) * #framelets * #bands) ¸ summing2] ≤ 3.734 Mbytes
For example, if spatial summing is not applied
(summing=1), either a single-band, 19-framelet (65.6 km) image or a 5-band
3-framelet (10.3 km) image can be collected. Each
A VIS image can be acquired simultaneously with an IR image, but the spacecraft can only receive data from one of the two THEMIS imagers at a time. The IR imager transfers data as it is being collected, while the VIS images are stored within an internal THEMIS buffer for later transfer to the spacecraft computer. Before storage of IR images on the spacecraft, one or more data reduction techniques may be selected. The time-delay integration (TDI) algorithm may be applied to improve the signal-to-noise ratio of each pixel by co-adding 16 independent measurements of each point on the ground. Lossless data compression may be applied to the image by the hardware Rice algorithm chip.
The IR and VIS cameras share the instrument optics and
housing, but have independent power and data interfaces to the spacecraft. In
Spring 2006, a software patch was loaded into the spacecraft memory to apply
spatial summing to IR images before downlink;
use of this patch decreases the effective bandwidth of the IR camera,
and allows for the collection of additional IR images. Final data stream formatting for both the IR
and VIS data is performed by the spacecraft processor. Further information about onboard processing
is available in the THEMIS Space Science
Review paper [6].
2.2 Data Product Overview
The four THEMIS multi-spectral standard data products (referred to collectively as the THM-EDR and THM-RDR data products) include raw and radiometrically calibrated image QUBEs at either thermal infrared or visible wavelengths. As discussed in the Instrument Overview (Section 2.1), one THEMIS observation results in either a visible image, an infrared image, or both an infrared image and a visible image with overlapping spatial coverage. Additional infrared images, called “reset” and “shutter” images, are collected throughout each orbit for calibration purposes. All images are stored in binary format with an attached ASCII label and header data objects.
All THEMIS experimental and reduced standard data products
are image QUBEs: VISEDR and IREDR contain raw data
values; VISRDR and IRRDR contain radiometrically
corrected radiance data. The label attached to each product contains
identification and observation parameters associated with the image. A
HISTORY data object, in ASCII format, follows the label within each product
header. For raw infrared products (IREDR), the header includes a second
data object containing binary telemetry information sampled regularly
throughout the observation. In an image QUBE each layer contains the data
from one instrument band; thus, a three band observation will result in a three
layer QUBE. Available bands for each camera are listed in Table 1a&b.
Tables 1a&b: THEMIS available bands
|
INFRARED BANDS |
|
VISIBLE BANDS |
||||
|
Band Numbers |
Center (mm) |
FWHM (mm) |
|
Band Numbers |
Center (mm) |
FWHM (mm) |
|
IR-1 |
6.78 |
1.01 |
|
V-1 |
0.425 |
0.049 |
|
IR-2 |
6.78 |
1.01 |
|
V-2 |
0.540 |
0.051 |
|
IR-3 |
7.93 |
1.09 |
|
V-3 |
0.654 |
0.053 |
|
IR-4 |
8.56 |
1.16 |
|
V-4 |
0.749 |
0.053 |
|
IR-5 |
9.35 |
1.20 |
|
V-5 |
0.860 |
0.045 |
|
IR-6 |
10.21 |
1.10 |
|
|
|
|
|
IR-7 |
11.04 |
1.19 |
|
|
|
|
|
IR-8 |
11.79 |
1.07 |
|
|
|
|
|
IR-9 |
12.57 |
0.81 |
|
|
|
|
|
IR-10 |
14.88 |
0.87 |
|
|
|
|
There are two THEMIS derived standard data products: visible apparent brightness records (VISABR) and infrared brightness temperature records (IRBTR). These products are calculated from a single band of the corresponding RDR product: IRBTRs are derived from band IR-9, or the first available band; VISABRs are derived from band V-3, or the first available band. Each brightness record is stored as an 8-bit IMAGE with an attached label containing identification and the geometric parameters calculated for the center of the observation.
2.3 Standards Used in Generating Data Products
2.3.1 PDS Standards
The THM-EDR and THM-RDR data products comply with Planetary Data System standards for file formats and labels, as specified in the PDS Standards Reference [4].
2.3.2 QUBE Object
All multi-spectral THEMIS data products make use of the
PDS spectral QUBE object, adapted from the
Figure 1a: THEMIS QUBE core structure Figure 1b. Exploded view of PDS QUBE
The QUBE object has an attached label containing pertinent observation information, and header data objects (Figure 2). Required keywords, in the “keyword=value” text format of PDS labels, define QUBE structure, CORE parameters, and BAND_BIN information. The header data objects contain information related to the image; for THEMIS QUBEs these may include a HISTORY object and a telemetry TABLE object.
Figure 2: Example of a THEMIS VISEDR QUBE: attached label, header data object, and image QUBE
2.3.3 IMAGE Object
THEMIS brightness products (IRBTR and VISABR) make use of the PDS IMAGE object defined in the PDS Standards Reference [4]. An IMAGE is a two-dimensional array of values organized as line_samples and lines. A THEMIS IMAGE is derived from a single band of a THM-RDR QUBE and has the same dimensions as that band. Each THEMIS IMAGE has an attached label, shown conceptually in Figure 3, containing a summary of observation information in the “keyword=value” format.
Figure 3: Example of a THEMIS IRBTR: attached label and IMAGE data
2.3.4 Time Standards
The time stamp (SPACECRAFT_CLOCK_START_COUNT) stored with each standard data product is the value of the spacecraft clock at the time of data acquisition of the leading edge of the first detector in the array (filter 1), even if filter 1 is not downlinked. For VIS QUBEs, this time is calculated from the UNCORRECTED_SCLK_START_COUNT and may differ by as much as 4 seconds, depending on which bands are acquired in the observation. The stop time stamp, SPACECRAFT_CLOCK_STOP_COUNT, is calculated from the sum of the UNCORRECTED_SCLK_START_COUNT and IMAGE_DURATION. For VIS QUBEs, the difference of the start and stop time stamps may not be equivalent to IMAGE_DURATION, depending on which bands are acquired in the observation.
The spacecraft clock value is equal to the number of seconds since 12:00 a.m. 1/01/1980 GMT. This number can vary from the number of seconds recorded on earth due to variations in the spacecraft’s oscillator or relativistic effects. The portion of the number that occurs after the decimal point is a count of “clock tics” which are 1/256th of a second long; the decimal portion will always be between 0 and 255. All data products also contain time values in UTC (Universal Time Coordinated) and ET (Ephemeris Time) formats, translated from the spacecraft event times. UTC is the date (year, month, day) and time (hour, minute, second) in GMT. ET is the time in seconds since January 1, 2000 at 12:00:00 in Barycentric Dynamical Time (TDB).
2.3.5 Coordinate Systems
The THM-EDR and THM-RDR data products are not projected into any coordinate system. The image QUBEs are maintained in the raw raster order produced by the instrument, reorganized to group together the data from each band. The QUBE layers are not spatially registered. Layers within a single QUBE can be out of registration with each other by up to 10 lines and/or columns.
THEMIS brightness products (IRBTR and VISABR) are also not
projected into any coordinate system, however they do contain some basic
geometric parameters in the attached header. All geometric values are
based on Mars IAU 2000 areocentric model with east positive longitude.
Geometric parameters are generated with a THEMIS specific
2.3.6 Orbit Numbering Conventions
The orbit number (ORBIT_NUMBER) stored with each THEMIS data product follows the convention established by the 2001 Mars Odyssey Project. During aerobraking, orbits are counted from the periapsis pass, with orbit 1 being the Mars Orbit Insertion pass. During mapping, orbits are counted from the descending equator crossing, incrementing from the last aerobraking orbit counted.
2.4 Data Product Contents
2.4.1 Data Processing Level
All THEMIS standard data products comply with NASA processing levels standards. THM-EDR are Level-0 spectral image QUBEs of raw THEMIS science data at the full resolution returned from the spacecraft, time ordered, with duplicates and transmission errors removed. THM-RDR are Level-1A spectral image QUBEs, radiometrically calibrated versions of the THM-EDR products. IRBTR and VISABR are Level-1A IMAGEs, calculated from the THM-RDR products with geometric parameters in the header.
2.4.2 Data Product Generation
The THEMIS data products will be generated by the staff at the ASU Mars Space Flight Facility. The data received on the ground are in the form of compressed, scaled, 8-bit "data numbers" (DN). Data processing will consist of decompression, radiometric calibration, and systematic noise removal. The instrument response functions necessary to perform calibration were acquired prior to launch using a thermal vacuum chamber at the SBRS facility (see THEMIS Calibration Report [7]). A detailed discussion of the processing techniques summarized below is available in the THEMIS Data Processing User’s Guide [8].
For IR data, the DN values represent the delta signal between the scene and the internal reference calibration flag. After decompression, the data is converted to scene radiance by: (1) adjusting for the gain and offset levels used during data collection; (2) correcting for drift or offset that occurs between observations of the calibration flag; and (3) converting signal to radiance using the instrument response function determined prior to launch.
For
Brightness records are dependent on the values available in the source calibrated data record. The VISABR data values are an 8-bit version of the calibrated radiance, scaled to the minimum and maximum radiance values of each source image. The IRBTR data values are a scaled representation of the brightness temperature measured in degrees Kelvin. To remove the scaling, apply the following function to each data value (x)
y = m
x + b
where m is the SCALING_FACTOR value and b is the OFFSET value, given in the IMAGE label.
2.4.3 Data Product Archive
Data will be accumulated, calibrated, and validated at the
ASU Mars Space Flight Facility. The size of individual data products
depends on several factors: image type (
The estimated total volume of data to be collected over the course of the mission is limited by the available downlink allocated to THEMIS. Many factors affect the actual downlink available on any given day, which can vary from 0 to more than 400 Mbytes per day. THEMIS mission planners will maximize data collection by balancing the day’s available allocated downlink against the size-defining parameters of the daily planned observations (VIS/IR, image length, number of bands).
Data products will be archived and released following the agreement outlined in the 2001 Mars Odyssey Orbiter Archive Plan [2]. Due to the large volume of data products expected from the mission, physical copies will be made for PDS long-term archive purposes only. All other data distribution will be facilitated through an online THEMIS data archive service, maintained by the ASU Mars Space Flight Facility.
2.4.4 Labeling and Identification
Each THEMIS data product is stored in a single file following the PDS SPECTRAL_QUBE format. Data products are uniquely identified by the PRODUCT_ID which is based on the abbreviated description of the product type, the data collected time, and the data processing level (see Section 3.1). File names follow the PDS convention of “PRODUCT_ID”.QUB or “PRODUCT_ID”.IMG.
Each product has an attached PDS label (see Section 3.3), which includes a PRODUCT_VERSION_ID keyword in the event that a revision to the product must be made after the initial public release. If a revision is required, the PRODUCT_VERSION_ID value will be incrimented, an ERRATA_ID will be established, and the change made will be documented. An ERRATA_ID value takes the form of ODTaa_rrrr_v.v, where
ODTaa is the abbreviated dataset description; [ ODTIB = IRBTR dataset; ODTIE = IREDR dataset; ODTIR = IRRDR dataset; ODTVB = VISABR dataset; ODTVE = VISEDR dataset; ODTVR = VISRDR dataset; ]
rrrr is a zero padded, 4-digit RELEASE_ID number identifying when the product was originally released; [ 0001 = data released in October 2002 ]
v.v is the PRDUCT_VERSION_ID value [ 1.0 = first release of product ]
Every ERRATA_ID will be documented in the ERRATA.TXT, the appropriate ODTaaREL.CAT, and the modified fields of the INDEX.TAB. For QUBE objects (THM-EDRs and THM-RDRs), a description of the applied errata will be added to the HISTORY object (see Appendix A.8).
3. Detailed Data Product Specifications
3.1 Data Product Structure and Organization
Each THEMIS data product is an individual file with a unique label. Data products are organized in the time-sequential order that they were collected during the mission. Each file name consists of an alphanumeric identifier following the pattern “AooooonnnPPP.EXT”, where
A is a 1-letter description of the type of image collected; [ V = visible image; I = infrared image; R = infrared reset image; S = infrared shutter image ]
ooooo is a 5-digit mission orbit number when the image was collected; [ 01000 = mapping orbit number example ]
nnn is a 3-digit image sequence number indicating the order that images were collected each orbit; [ 001 = first image collected in the xxxxx orbit ]
PPP is a 3-letter description of the processing level of the image data; [ABR = visible derived apparent brightness data; BTR = infrared derived brightness temperature data; EDR = raw data; RDR = radiometrically calibrated data ]
.EXT is a 3-letter extension describing this product; [ IMG = PDS IMAGE format; QUB = PDS SPECTRAL_QUBE format ]
More information, including mission orbit numbers, spacecraft clock times, processing dates, and version numbers, are accessible in the ASCII label described in Section 3.3 below.
3.2 Data Format
The THM-EDR data products are uncompressed, binary,
band-sequential QUBEs of 8-bit integers. The
image width is fixed (320 pixels for IR, 1024 pixels for
The format of the IRRDR QUBEs is identical to the source IREDR QUBE, except that the data are stored as floating point values, scaled into 16-bit integers. To recover the floating point values, apply the following function to each data value per band (xi)
yi
= mixi
+ bi
where mi is the BAND_BIN_MULTIPLIER value for band i, and bi is the BAND_BIN_BASE value for band i. These scaling factors are given in the BAND_BIN group within each IRRDR QUBE label.
The format of the VISRDR QUBEs is identical to the source VISEDR QUBE, except that the data are stored as 16-bit MSB integers.
The THEMIS brightness products are uncompressed, binary, single band IMAGEs of 8-bit integers. The length and width of the IMAGE is identical to a single band of the source THM-RDR QUBE.
For IR QUBEs, missing data pixels are set to the CORE_NULL value and the total count of missing lines is stored in the MISSING_SCAN_LINES keyword. For VISEDR QUBEs, missing data pixels are either filled with zero values, if several complete lines are missing, or they are filled with a pattern of values, if a section of a line is missing. In VISRDR QUBEs, the missing data pixels are set to zero.
3.3 Labels
The PDS label describes the structure, content, and observation specifications of the data. It is attached as ASCII text at the beginning of each image file. Information in the label are stored in a “keyword=value” text format and structured in the Object Definition Language (ODL) of PDS. Example labels are shown in Appendices A.1-A.6; individual keyword items are defined in Appendices A.7-A.9.
3.3.1 File Identification and Structure Label
The first lines of the label are the file identification keywords and associated values. Next are the file structure keywords, which define the number and size of records in the data file, followed by the pointer keywords, which define the start byte of the header data objects and the image data. Finally, “identification data elements” define parameters of the mission, spacecraft, instrument team, and data stream. See Appendix A.7 for a detailed description of these keywords.
3.3.2 HISTORY Object Structure
A HISTORY object is available in each THEMIS QUBE. The history object structure keywords define the size and format of the data object stored later in the header. The HISTORY object itself is a structured series of text entries identifying all previous computer manipulations of the data in the file; the format is not intended to be compliant with PDS-ODL standards. HISTORY entries may include identification of source data, processes performed, processing parameters, and dates and times of processing. See Appendix A.8 for a detailed description of the entries and keywords used with THM-EDR and THM-RDR HISTORY objects.
3.3.3 Telemetry Table Object Structure
The telemetry (TLM) table is only available in the raw infrared data products (IREDR). The TLM table object structure keywords define the size and format of the table object stored later in the header. See Appendix A.7 for a detailed content description of the TLM table.
The TLM table itself follows the PDS TABLE structure using fixed length binary records sorted time-sequentially. The table structure is defined in an external, ASCII file identified in the pointer keyword as “tlm.fmt”. It contains details such as the table dimensions, a general description of the telemetry data source, and definitions of each table column. Column definitions include the following details: name, starting position (in bytes), size (in bytes), data type, description, and scaling factors if applicable. In some cases, the column being described is composed of multiple bit-fields; the individual meaning of each bit-field is described with the same details listed above.
The TLM table records can be accessed using the DAVINCI software package described in Section 4.1 below.
3.3.4 QUBE Object Label
The QUBE object keywords make up the bulk of a QUBE label and are organized by the following sub-structure descriptions:
QUBE structure - para