urn:nasa:pds:mgs-rss:data-maps:ggm0890a 1.0 1.22.0.0 Product_Observational 2025 MGS RSS This file contains a digital map of Mars gravity accelerations derived from radio tracking of the Mariner 9, Viking, and Mars Global Surveyor spacecraft. The map is vertical gravity in milligals and the data cover 1997-09-12T00:00:00Z to 1998-09-17T23:59:59Z. David Smith 1 Goddard Space Flight Center https://ror.org/0171mag52 2025-02-25 1.0 This product, GGM0890A.IMG, was originally released as part of the PDS3 MGS-M-RSS-5-SDP-V1.0 data set. The metadata have been migrated to PDS4. The keywords WESTERNMOST_LONGITUDE,EASTERNMOST_LONGITUDE, MINIMUM_LATITUDE, and MAXIMUM_LATITUDE. As used in radio science products, these are the extreme values at pixel centers rather than the extremes of the area represented. For example, if the image has 180 rows at equally spaced latitudes (-89.5, -88.5, ..., -0.5, +0.5, ..., +89.5) then MINIMUM_LATITUDE = -89.5 and MAXIMUM_LATITUDE = 89.5 A more conventional usage might have these same keywords set to -90.0 and +90.0, respectively, because those are the limits of the area represented by the pixels. In cases where the radio science image has 181 rows (-90.0, -89.0, ...,-1.0, 0.0, +1.0, ..., +90.0), the radio science label would show MINIMUM_LATITUDE = -90.0 and MAXIMUM_LATITUDE = 90.0 The more conventional label, in this case, would have the same values. 1997-09-12T00:00:00Z 1998-09-17T23:59:59Z Science Derived Mars Global Surveyor Gravity Anomaly Maps Data Mars Global Surveyor Mission urn:nasa:pds:context:investigation:mission.mars_global_surveyor data_to_investigation Mars Global Surveyor Host urn:nasa:pds:context:instrument_host:spacecraft.mgs is_instrument_host Mariner 9 Host urn:nasa:pds:context:instrument_host:spacecraft.mr9 is_instrument_host Viking Orbiter 1 Host urn:nasa:pds:context:instrument_host:spacecraft.vo1 is_instrument_host Viking Orbiter 2 Host urn:nasa:pds:context:instrument_host:spacecraft.vo2 is_instrument_host Radio Science Subsystem (RSS) Instrument urn:nasa:pds:context:instrument:mgs.rss is_instrument Radio Science Subsystem (RSS) Instrument urn:nasa:pds:context:instrument:rss.mr9 is_instrument Radio Science Subsystem (RSS) Instrument urn:nasa:pds:context:instrument:rss.vo1 is_instrument Radio Science Subsystem (RSS) Instrument urn:nasa:pds:context:instrument:rss.vo2 is_instrument Mars Planet urn:nasa:pds:context:target:planet.mars data_to_target Array_3D_Image cartography_parameters_to_image_object -179.5 179.5 89.5 -89.5 Equirectangular 0 0 0 Coordinate Pair 59110.0455857414781 59274.6975233062185 1.00278551532033422 1 -10669445.5541951191 5334722.77709755953 Planetocentric MGM0890 3396190 3396190 3396190 Positive East Array_3D_Image display_settings_to_array Sample Left to Right Line Top to Bottom urn:nasa:pds:mgs-rss:data-sha:ggm0890a::1.0 data_to_derived_product MGS-M-RSS-5-SDP-V1.0:anom.mgm0890.xyz:GGM0890A.IMG data_to_derived_source_product 10.17189/1519757 PDS Planetary Plasma Interactions Node This is the first version converted to PDS4. The DOI references the source PDS3 data set. GGM0890A.IMG 1999-09-09T15:07:42 129600 6fe85968cf217d6994f71d06212ab736 Array_3D_Image 0 3 Last Index Fastest The model was constructed from 515,878 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. Spacecraft Total Observations -------------------- ------------ Mariner 9 69992 Viking 1 109176 Viking 2 79545 Mars Global Surveyor 257165 -------------------- ------------ Total 515878 Performance of the gravity model can be evaluated by computing the orbit position discrepancy between overlapping arcs. The set of overlapping arcs included nine 4.5 day arcs between March 27 and May 1, 1998 (SPO-1), and 23 4.5 day arcs between May 31 and September 8, 1998 (SPO-2). Results are summarized in the table below: Average RMS Overlaps for Gravity Model MGM0890 Time Interval Radial Cross-Track Along-Track Total (m) (m) (m) (m) ------------- ------ ----------- ----------- ------ SPO-1 35.9 934.1 424.0 1034.1 SPO-2 29.1 116.5 491.2 510.5 SignedMSB2 mm/s/s Band 1 1 Line 180 2 Sample 360 3 -32768 The Digital Map contains values of vertical gravity in 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.