PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 720 FILE_RECORDS = 181 ^IMAGE = "GGM2BE60.IMG" INSTRUMENT_HOST_NAME = "MARS GLOBAL SURVEYOR" TARGET_NAME = MARS INSTRUMENT_NAME = "RADIO SCIENCE SUBSYSTEM" DATA_SET_ID = "MGS-M-RSS-5-SDP-V1.0" ORIGINAL_PRODUCT_ID = "gmm2b.60x60.anomalyerror_grid" PRODUCT_ID = "GGM2BE60.IMG" PRODUCT_RELEASE_DATE = 2000-09-30 DESCRIPTION = " This file contains a digital map of Mars gravity anomaly errors. Gravity anomalies were evaluated with respect to the GMM2B model to 60x60. The anomaly errors are the uncertainties in the anomaly values derived using the covariances in the model. The model was constructed from 955,115 observations, summarized in the table below. MGS data are limited to tracking from the Aerobraking Hiatus and Science Phasing Orbit (SPO) subphases of the Orbit Insertion phase of the mission and from February 1999 to February 2000 after the orbit was circularized. Time Periods Total Arcs Observations ----------------------- ---- ------------ Hiatus 2 24119 SPO-1 8 31001 SPO-2 16 157972 Feb-Mar 1999 9 76813 Apr 1999 - Feb 2000 47 665210 ----------------------- ---- ------------ Total 955115 The gravity model was derived using a Kaula type constraint: sqrt(2)*13*10**(-5)/L**2 (Kaula, W.M., Theory of Satellite Geodesy, Blaisdell, Waltham, MA, 1966). The analysis and results were described by F.G. Lemoine, D.D. Rowlands, D.E. Smith, D.S. Chinn, G.A. Neumann, and M.T. Zuber at the Spring Meeting of the American Geophysical Union, May 30 - June 3, 2000, Washington. DC. The gravity anomalies are evaluated on a reference ellipsoid with the following constants: GM = 0.42828371901284e+14 m**3/s**2, semi-major axis 3397000.0 m, the 1991 IAU rotation rate (7.088218081252279e-4 rad/s), and an inverse flattening for the ellipsoid (1/f) of 196.877360. This selection of 1/f as the nominal shape of the reference equipotential surface effectively removes 95 percent of J2. The map is constructed in the form of a PDS image having 181 lines of 360 pixels each." START_TIME = 1997-10-13T00:00:00 STOP_TIME = 2000-02-29T12:05:00 SOFTWARE_NAME = "SOLVE.F90INLINE3;2000.01" PRODUCT_CREATION_TIME = 2000-09-18T00:00:00 PRODUCER_ID = "MGS RST" OBJECT = IMAGE LINES = 181 LINE_SAMPLES = 360 SAMPLE_TYPE = MSB_INTEGER SAMPLE_BITS = 16 OFFSET = 0.0 SCALING_FACTOR = 0.01 DESCRIPTION = "The Digital Map contains uncertainties associated with gravity anomalies where the uncertainties were evaluated using covariances in the model. Units of uncertainties are milligals (1 milligal = 0.01 mm/s/s). The true values can be obtained by multiplying the sample in the map by SCALING_FACTOR and then adding OFFSET. " END_OBJECT = IMAGE OBJECT = IMAGE_MAP_PROJECTION ^DATA_SET_MAP_PROJECTION = "DSMAP2.CAT" COORDINATE_SYSTEM_TYPE = "BODY-FIXED ROTATING" COORDINATE_SYSTEM_NAME = PLANETOCENTRIC MAP_PROJECTION_TYPE = "SIMPLE CYLINDRICAL" A_AXIS_RADIUS = 3397.00 B_AXIS_RADIUS = 3397.00 C_AXIS_RADIUS = 3397.00 FIRST_STANDARD_PARALLEL = "N/A" SECOND_STANDARD_PARALLEL = "N/A" POSITIVE_LONGITUDE_DIRECTION = "EAST" CENTER_LATITUDE = 0.0 CENTER_LONGITUDE = 0.0 REFERENCE_LATITUDE = 0.0 REFERENCE_LONGITUDE = 0.0 LINE_FIRST_PIXEL = 1 LINE_LAST_PIXEL = 181 SAMPLE_FIRST_PIXEL = 1 SAMPLE_LAST_PIXEL = 360 MAP_PROJECTION_ROTATION = 0.0 MAP_RESOLUTION = 1.0E+00 MAP_SCALE = "N/A" MAXIMUM_LATITUDE = 90.0 MINIMUM_LATITUDE = -90.0 EASTERNMOST_LONGITUDE = 179.0 WESTERNMOST_LONGITUDE = -180.0 LINE_PROJECTION_OFFSET = 90.0 SAMPLE_PROJECTION_OFFSET = 180.0 END_OBJECT = IMAGE_MAP_PROJECTION END