PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 1998-07-31 NOTE = "N/A" END_OBJECT = TEXT END Mars Pathfinder Radio Science Data Archive Surface Operations (MPF-M-RSS-1/5-RADIOTRACK-V1.0) AAREADME.TXT 31 July 1998 W. M. Folkner Jet Propulsion Laboratory ============================================================================== INTRODUCTION ============================================================================== This compact disc contains archival raw, partially processed, and ancillary/supporting radio science data acquired during Mars Pathfinder surface operations, July 4, 1997 to October 7, 1997. The radio observations were carried out using the Pathfinder and Earth-based receiving stations of the NASA Deep Space Network (DSN), providing measurements of the range and range-rate (Doppler) between Earth and Pathfinder. The entire data set is contained on two volumes, designated MPRS_0001 and MPRS_0002. Only the raw range and Doppler data (in ATDF or TDF files) require significant storage volume and are different on the two volumes. The more processed data along with calibrations are duplicated on each volume for convenience. ============================================================================== VOLUME SET INFORMATION ============================================================================== Each archive volume has the structure illustrated in the diagram below. The INDEX directory notes the volume location of all files. Most files are duplicated on all volumes for convenience. The primary data types for these volumes are the DSN Orbit Data File (ODF) in the ODF directory. The ODF files contain data sampled at 60-second intervals. The ODF files are binary files, for which the format is described in the associated LBL files. Archival Tracking Data File (ATDF or TDF) files are considered backup data to the ODF data. The ATDF files contain data sampled at 0.1 second intervals, which is much greater than necessary for the geodetic analysis performed for the Rotational and Orbital Dynamics investigation. The TDF files are binary files, for which the format is described in the associated LBL files. The range and Doppler measurements need to be calibrated for media delays due to the Earth's troposphere and ionosphere. The CALIB directory contains these calibrations based on measurements made at the DSN stations. The troposphere calibrations are comprised of a seasonal model, in the file 7001T365.TRO, and daily corrections to the seasonal model, collected by month in the files 7xxxTyyy.TRO, where xxx and yyy denote the dates covered on the file, from day-of-year xxx to day-of-year yyy. The ionosphere calibrations files each cover one month of tracking data, in the files 7xxxCyyy.ION. Earth orientation information used in the data processing is contained in the EOP directory. The DOCUMENT directory contains descriptions of these file formats. The locations of the DSN tracking stations used to acquire the data are given in the file INST.CAT in the CATALOG directory. The DSN ranging instrumentation is calibrated before each pass, and sometimes possible systematic errors can be investigated by examining these calibrations. The ranging calibrations are available in the TDF files. For ease of use, an ASCII version of the Pathfinder ranging calibration data is included in the file RANGECAL.TAB in the CALIB directory. An ASCII version of all the tracking data is also included in summary tables in the REDUCED directory. These contain only the 'good' points, where outliers thought to be due to instrumental error have been removed. The data on the REDUCED files have had the Earth troposphere and ionosphere calibrations applied. For determining properties of Mars, the Pathfinder data are most valuable when combined with similar measurements from the Viking landers. The REDUCED directory contains an ASCII form of the Viking lander range and Doppler data currently available. The original raw Viking data is not included here. Like the Pathfinder data, the Viking lander data have had calibrations for Earth troposphere and ionosphere applied. In addition, the Viking lander range data have been corrected for delay due to solar plasma effects from 1976 through 1980 based on dual-frequency calibrations made by the Viking orbiters. The Pathfinder data, in combination with the Viking lander data, were used to solve for Mars rotation parameters as well as the lander locations. The RESULTS directory contains these estimated parameters. Two sets of rotation parameters are included, one using the standard cartographic system based on the right ascension and declination of the spin axis direction (MAR_RA_D) and one based on the obliquity and longitude of the node of the equator (MARS_ROT). The results are described in more detail in the paper "Interior Structure and Seasonal Mass Redistribution of Mars from Radio Tracking of Mars Pathfinder", W. M. Folkner et al., Science vol. 278, pp. 1749-1752, 1997 [FOLKNERETAL1997B]. The diagram below shows the organization of each volume, starting from the root of the compact disc. root | |- AAREADME.TXT |- VOLDESC.CAT |- ERRATA.TXT | |- CALIB | | | |- CALINFO.TXT Overview of Directory | |- ydddTddd.TRO DSN Troposphere calibrations | |- ydddCddd.ION DSN Ionosphere calibrations | |- RANGECAL.TAB DSN ranging calibrations | |- *.LBL Detached PDS labels | |- CATALOG | | | |- CATINFO.TXT Streamlined PDS catalog files | |- DATASET.CAT for mission, host, instrument, | |- INST.CAT data set (files evolve as | |- INSTHOST.CAT mission progresses). | |- MISSION.CAT | |- PERSON.CAT | |- REF.CAT | |- DOCUMENT | | | |- DOCINFO.TXT Overview of directory | |- TRK_2_18.TXT ODF file format description | |- TRK_2_21.TXT EOP document | |- TRK_2_23.TXT Troposphere/ionosphere calibration format | |- TRK_2_25.TXT TDF file format description | |- EOP | | | |- EOP12_97.TXT Earth orientation information | |- *.LBL Detached PDS labels | |- INDEX | | | |- INDXINFO.TXT Overview of directory | |- INDEX.LBL Label to INDEX.TAB | |- INDEX.TAB List of data file contents, this volume | |- CUMINDEX.LBL Label to CUMINDEX.TAB | |- CUMINDEX.TAB List of data file contents, all volumes | |- ODF | | | |- yddddddc.ODF Binary tracking ODF data | |- *.LBL Detached PDS labels | |- TDF | | | |- yddddddc.TDF Binary tracking ATDF data | |- *.LBL Detached PDS labels | |- REDUCED | | | |- MPF_RANG.TAB MPF range data | |- MPF_DOPP.TAB MPF Doppler data | |- VIK_RANG.TAB Viking Lander range data | |- VIK_DOPP.TAB Viking Lander Doppler data | |- *.LBL Detached PDS labels | |- RESULTS | | | |- MARS_ROT.TAB Estimated Mars rotation angles | |- MAR_RA_D.TAB Estimated Mars rotation angles | |- LANDER.TAB Estimated lander positions | |- *.LBL Detached PDS labels ============================================================================== DISC FORMAT ============================================================================== The disc is organized according to the PDS standard for "one data set, many volumes." This file (AAREADME.TXT) and a PDS volume object definition (VOLDESC.CAT) are included at the root level. The remaining directories at the root level contain documentation, data files and detached PDS labels. ============================================================================== FILE FORMAT ============================================================================== All data files on the disc are accompanied by detached PDS labels, which describe their contents. PDS TEXT objects have attached labels. Detached labels have the same file name as the data file except that the label name has the suffix "LBL". Detached PDS labels for multi-file documents have distinctive file names ending with ".LBL". Detailed documentation on file structure is available for some file types in Software Interface Specifications in the DOCUMENT directory. ODF and TDF files have full PDS labels which describe format and content completely. For other file types, where no electronic version of the SIS was available, the PDS label provides a reference to a hard copy document. See the DESCRIPTION keyword in each PDS label. Text files, including data files of ASCII text and all labels (*.LBL files), are delimited with carriage-return (ASCII 13) line-feed (ASCII 10) pairs at the end of each line. Detached labels and text files (*.TXT file names) have fixed length records of 80 bytes to facilitate their use as either fixed-length record files or as stream files with carriage-return line-feed delimiters. ============================================================================== SOFTWARE ============================================================================== Software for parsing the binary data files has been developed at several institutions to support NASA flight projects. Because parsing must be done at the bit level and the code is usually written for a narrow platform-specific application, no software has been included as part of this archival product. ============================================================================== ACKNOWLEDGMENTS ============================================================================== These data were collected under auspices of the Mars Pathfinder Project. Much of the format information and generation of file labels was done based on the work of Dick Simpson, Stanford University, who developed formats for the Mars Global Surveyor Project. At PDS the assistance of Betty Sword was appreciated. ============================================================================== DISCLAIMER ============================================================================== Although considerable care has gone into making this volume set, errors are both possible and likely. Users of the data are advised to exercise the same caution as they would when dealing with any other unknown data set. Reports of errors or difficulties would be appreciated. Please contact the person listed below. ============================================================================== COGNIZANT PERSONNEL ============================================================================== The person responsible for construction and release of this volume set is Bill Folkner, Participating Scientist for the Mars Pathfinder Rotation and Orbit Dynamics Investigation. William M. Folkner JPL m/s 238-600 4800 Oak Grove Dr. Pasadena, CA 91109 Tel: 818-354-0443 FAX: 818-393-4965 William.Folkner@jpl.nasa.gov