Data Set Information
DATA_SET_NAME MARS EXPRESS MARS MARSIS REDUCED DATA RECORD SUBSURFACE V2.0
DATA_SET_ID MEX-M-MARSIS-3-RDR-SS-V2.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview=================MARSIS Level 2 data products consist of Level 1b data that have beenuncompressed, corrected for Automated Gain Control, aligned to areference altitude and, except for data acquired using the SS2 mode,range-processed after correcting for the distortion of the transmittedsignal caused by the ionosphere. Echoes collected in the acquisition(ACQ) phase, having a much smaller bandwidth, do not have a verticalresolution sufficient for scientific analysis, and thus are not usedin generating Reduced Data Records. Geometric information needed tolocate observations in space and time is also provided in the DataSet.Parameters==========MARSIS data are the result of the processing of groups of echoescalled frames. A frame is produced by the coherent summation of manytens of echoes. Each frame is recorded as a time series of complexsignal samples. Scientific data in a frame are complemented by a setof engineering data, produced by the instrument and recordingparameter values used in pulse transmission, echo reception andon-board processing, and by geometric information needed to locateobservations in space and time.Processing==========Level 2 processing of subsurface sounding data consists of severalsteps, needed to convert the instrument telemetry into a collection ofradar echoes that can be used for geological analysis andinterpretation of the Martian subsurface. These are: Data de-compression: 8-bit spectrum samples are converted back to4-byte real numbers. AGC compensation: the gain scaling factor, applied during AutomatedGain Compensation, is applied to the data. Receiving time compensation: echoes are shifted in time to refer themto a common altitude above the Martian ellipsoid. Range compression: the received signal is convolved with thetransmitted signal to increase range resolution and signal-to-noiseratio. Ionosphere distortion correction: an algorithm to correct ionospheredispersion of the signal, called 'contrast method', is applied to thedata.Depending on the instrument mode, some of the above steps may notapply (for example, range processing is performed on board in modeSS2). The final result is a file containing all complex echoescollected by MARSIS in the course of a single orbit.Data====Data Products need to accommodate the different data structuresproduced by different subsurface sounding modes of the instrument.There is a single type of Data Product specialized into five differentsubtypes, one for each subsurface sounding mode:R_SSx Subsurface Sounding data that have been uncompressed,calibratedand range-processed, together with geometry informationWhere 'x' stands for a number between 1 and 5.SSx_RDR Data Products consist of two files, one of which contains aPDS binary TABLE object while the other is a PDS label describing itsstructure. The first file contains the instrument data proper,organised into frames. Each frame corresponds to a record in the file,which is also a row in the PDS binary TABLE object into which framesare organised. A Data Product contains all frames acquired using thesame instrument mode in tracking (TRK) state during a single orbit.Ancillary Data==============No Ancillary data are provided.Coordinate System=================Locations on the surface of Mars are expressed in planetocentriccoordinates. Longitude increases to the East and is comprised in therange 0 - 360 degrees.Software========MARSIS data products can be read by the PDS software NASAView, whichreads a PDS label and displays the associated image or table.Media/Format============The standard distribution format for the data is transfer throughInternet from the Planetary Science Archive of ESA, which can beaccessed at the following URL:http://www.cosmos.esa.int/web/psa/psa-introductionConfidence Level Overview=========================This data set contains all data for the Mars Express MARSIS for theinterval described above. Every effort has been made to ensure thatall data returned by the spacecraft is included and that processing isaccurate.Review======The MARSIS EDR data have been reviewed internally by the Mars ExpressMARSIS team prior to release to the PDS. The data set has been alsopeer reviewed by the PSA.Data Coverage and Quality=========================Data in this dataset have been acquired only in the last six months ofthe nominal mission, because of the delay in the deployment of theMARSIS antenna. Because of this, coverage is limited mainly tosouthern latitudes.Data quality in a data product label is indicated through theDATA_QUALITY_ID element, and measures the median of the total echopower across the orbit. The permitted values of DATA_QUALITY_ID arethe following: 0: data quality unknown 1: median data quality index in the bottom 25% of computed values 2: median data quality index in the bottom 50% of computed values 3: median data quality index in the top 50% of computed values 4: median data quality index in the top 25% of computed valuesFor instrument mode transmitting at two different frequencies,DATA_QUALITY_ID reports a value for every frequency.Limitations===========There are no known limitations at this time.
DATA_SET_RELEASE_DATE 2016-10-01T00:00:00.000Z
START_TIME 2005-05-21T11:18:58.000Z
STOP_TIME 2005-11-30T06:44:43.000Z
MISSION_NAME MARS EXPRESS
MISSION_START_DATE 2003-02-19T12:00:00.000Z
MISSION_STOP_DATE N/A (ongoing)
TARGET_NAME PHOBOS
MARS
NON SCIENCE
TARGET_TYPE SATELLITE
PLANET
CALIBRATION
INSTRUMENT_HOST_ID MEX
INSTRUMENT_NAME MARS ADVANCED RADAR FOR SUBSURFACE AND IONOSPHERE SOUNDING
INSTRUMENT_ID MARSIS
INSTRUMENT_TYPE RADAR
NODE_NAME planetary plasma interactions
ARCHIVE_STATUS ARCHIVED - ACCUMULATING
CONFIDENCE_LEVEL_NOTE Data quality in a data product label is indicated through the DATA_QUALITY_ID element, and measures the total power in radar echoes.
CITATION_DESCRIPTION Orosei, R., F. Cantini, M. Cartacci, A. Cicchetti and R. Noschese, MARS EXPRESS MARS MARSIS REDUCED DATA RECORD SUBSURFACE V2.0, MEX-M-MARSIS-3-RDR-SS-V2.0, ESA Planetary Science Archive, 2016.
ABSTRACT_TEXT This dataset contains subsurface sounding data from the MARS EXPRESS MARS MARSIS EXPERIMENT DATA RECORD V2.0 Data Set that have been uncompressed, corrected for Automated Gain Control, aligned to a reference altitude and, except for data acquired using the SS2 mode, range processed after correcting for the distortion of the transmitted signal caused by the ionosphere.
PRODUCER_FULL_NAME ROBERTO OROSEI
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