Radio Science data sets

Data Set Overview

The Mars Exploration Rover 1 (MER1) Radio Science (RS) data archive contains raw radio tracking data collected during the surface lifetime of the MER1 Rover. The data contain potentially valuable information on the rotation dynamics of Mars, extending the previous data available from the Viking and Mars Pathfinder landers. For more information on the investigations see [FOLKNERETAL1997A].

The raw data include two primary data types. Orbit Data Files (ODFs) contain measurements of the Doppler shift of the MER1 radio signal as measured by tracking stations of the NASA Deep Space Network. Ultra-High-Frequency Doppler Files (UHFD) contain measurements of the Doppler shift of the MER1 radio signal as measured by a counter on the Mars Odyssey orbiter.

Parameters

The ODF contains the radio tracking information (range and Doppler) needed by spacecraft navigation teams and investigators interested in determining gravitational fields of bodies such as Mars. Each ODF is accompanied by a full PDS label which describes both the content and format of the associated file.

ODF fields include:

Narrowband spacecraft VLBI, Doppler mode (cycles)
Narrowband spacecraft VLBI, phase mode (cycles)
Narrowband quasar VLBI, Doppler mode (cycles)
Narrowband quasar VLBI, phase mode (cycles)
Wideband spacecraft VLBI (nanoseconds)
Wideband quasar VLBI (nanoseconds
One-way Doppler (Hertz)
Two-way Doppler (Hertz)
Three-way Doppler (Hertz)
One-way total count phase (cycles)
Two-way total count phase (cycles)
Three-way total count phase (cycles)
PRA planetary operational discrete spectrum range (range units)
SRA planetary operational discrete spectrum range (range units)
Azimuth angle (degrees)
Elevation angle (degrees)
Hour angle (degrees)
Declination angle (degrees)
X angle (where +X is east) (degrees)
Y angle (where +Y is east) (degrees)
X angle (where +X is south) (degrees)
Y angle (where +Y is south) (degrees)

The UHFD contains the measurements of the Doppler shift of the MER1 radio signal received by the Mars Odyssey orbiter. Each UHFD is accompanied by a full PDS label which describes both the content and format of the associated file.

UHFD fields include:

Measurement time (second past J2000)
Measurement reference frequency indicator flag
Data quality flag
Absolute value of Doppler shift (Hertz)

Processing

Minimal processing has been done on the ODF and UHFD files, primarily including flagging data points that appear invalid during the formatting process.

Data

ODFs are stored in the ODF directory. File names are of the form yyddd_eee.DAT where yy is the two-digit year of the first data, ddd is the three-digit day-of-year of the first data point, and eee is the three-digit day-of-year of the last data point.

UHFDs are stored in the UHF directory. File names are of the form ODYyyyyddd_S254.CSV where yyyy is the four-digit year of the first data point, ddd is the three-digit day-of-year of the first data point, and S254 is a DSN designator for the Mars Exploration Rover 2.

Ancillary Data

Files are stored in the CALIB Directory. The CALIB directory includes files with station calibrations for Earth troposphere and ionosphere effects. Each file is accompanied by a PDS label.

Software

Software for parsing, reducing, and analyzing data such as these has been developed at several institutions. Because such software must usually operate at the bit-level and is written for a narrow range of platforms, it is not suitable for general distribution. No software is included with this archival data set.

Data Coverage and Quality

This archive includes all radio tracking data collected from MER1 beginning with landing on 2004-01-04 through 2004-02-03. Most of the data in the archive have not been evaluated for accuracy beyond preliminary screening.