PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 720 FILE_RECORDS = 181 ^IMAGE = "GGM0964E.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 = "mgm0964c18.50x50.anomalyerror_grid" PRODUCT_ID = "GGM0964E.IMG" PRODUCT_RELEASE_DATE = 1999-10-31 DESCRIPTION = " This file contains a digital map of Mars gravity anomaly errors. Gravity anomalies were evaluated with respect to the MGM0964C18 model to 50x50 (the approximate degree at which the modified Kaula Rule for Mars intersects the degree covariances of the coefficient standard deviations). The anomaly errors are the uncertainties in the anomaly values derived using the covariances in the model. The MGM0964C18 model was constructed from 353,648 Mars Global Surveyor 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 to February and March 1999 after the orbit was circularized. The solution used no data from either Viking or Mariner 9. Time Periods Total ----------------------- ------------ Hiatus and SPO 257165 February and March 1999 96483 ----------------------- ------------ Total 353648 Details of the analysis and results can be found in the DOCUMENT directory of this archival volume (see AAS99328.LBL). Or, see Lemoine et al., Paper AAS 99-328, Astrodynamics Specialist Conference, Girdwood, Alaska, 16-19 August 1999. This paper describes both MGM0964C18 and an improved model, MGM0964C20. The gravity anomalies are evaluated on a reference ellipsoid with the following constants: GM = 0.4282838041570575e+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 = 1997-09-12T00:00:00 STOP_TIME = 1999-03-27T23:59:59 SOFTWARE_NAME = "SOLVE.SPECIAL;9603.02" PRODUCT_CREATION_TIME = 1999-09-01T00:00:00 PRODUCER_ID = "MGS RST" OBJECT = IMAGE LINES = 181 LINE_SAMPLES = 360 SAMPLE_TYPE = MSB_INTEGER SAMPLE_BITS = 16 OFFSET = 0.0 SCALING_FACTOR = 0.001 DESCRIPTION = "The Digital Map contains uncertainties associated with gravity anomalies where the gravity anomalies were evaluated using the MGM0964C18 model to 50x50. 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 = -0.5 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 = 179.5 END_OBJECT = IMAGE_MAP_PROJECTION END