OBJECT = DATASET DATA_SET_ID = 'MGN-V-RDRS-5-GDR-TOPOGRAPHIC-V1.0' OBJECT = DATASETINFO DATA_SET_NAME = 'MGN V RDRS 5 GLOBAL DATA RECORD TOPOGRAPHIC V1.0' DATA_SET_COLLECTION_MEMBER_FLG = N EVENT_START_TIME = 1990-09-15T16:22:14.871 EVENT_STOP_TIME = 1992-09-14T02:27:41.936 NATIVE_START_TIME = 'N/A' NATIVE_STOP_TIME = 'N/A' DATA_OBJECT_TYPE = 'IMAGE' DATA_SET_RELEASE_DATE = 1992-01-15 PROCESSING_LEVEL_ID = 5 PRODUCER_FULL_NAME = 'Peter G. Ford' PRODUCER_INSTITUTION_NAME = "Massachusetts Institute of Technology" SOFTWARE_FLAG = N DETAILED_CATALOG_FLAG = N PROCESSING_START_TIME = 1991-06-24T20:11:00 PROCESSING_STOP_TIME = 1992-12-04T00:55:49 DATA_SET_DESC = "Global Topographic Data Record (GTDR). The range to surface is derived by fitting altimeter echoes from the fan-beam altimetry antenna as a function of time to Hagfors' radar backscatter model templates. The ranges are subtracted from the spacecraft radial coordinate (derived from Doppler tracking), yielding measurements of planetary radius. The data are filtered to remove low-frequency errors in the in-plane elements of each spacecraft orbit, and then re-sampled into sinusoidal, Mercator, and north and south polar stereographic projections at a resolution of about 5x5 kilometers per pixel. A fifth image contains estimates of the absolute accuracy of the radius values in each pixel of the sinusoidal projection. This is derived by taking the root mean square of (a) the statistical accuracy anticipated from the template fitting and (b) the systematic errors estimated from the in-plane element filtration. Note that this is the absolute topographic accuracy -- relative errors are much smaller, about 10-15 meters in relatively flat areas. Except in the radius error image, each GTDR pixel is represented by a 16-bit integer. In sinusoidal images, pixels lying outside the domain of the projection are set to zero. In all images, pixels with unknown or unmeasured values are also set to zero. The remaining values are related to the planetary radius by the following equation: DN = (RADIUS ) - 6039999 In the radius error image, each pixel is represented by an 8-bit integer. Pixels lying outside the domain of the projection are set to zero, as are all pixels with unknown or unmeasured values. The remaining values are related to the radius error by the following equation: DN = (RADIUS-ERROR * 0.2) + 1 See: Software Interface Specification Document (Peter G. Ford, 1991, Global Altimetry and Radiometry Data Records, MIT-MGN-GxDR SIS Version 2.3, 40 p.) that is included on GxDR CD-ROMs. Note: There exist photoproducts that are identified as GxDRP (where x is E (Emissivity), S (Slope), RE (Reflectivity), or T (Topography)) however, they are not generated from the digital GxDR products. They are instead produced from the Magellan ARCDR (Altimetry and Radiometry Composite Data Record) data files." CONFIDENCE_LEVEL_NOTE = 'UNK' END_OBJECT = DATASETINFO OBJECT = DATASETTARG TARGET_NAME = 'VENUS' END_OBJECT = DATASETTARG OBJECT = DSPARMINFO SAMPLING_PARAMETER_NAME = 'PIXEL' SAMPLING_PARAMETER_RESOLUTION = 9282 MINIMUM_SAMPLING_PARAMETER = 'N/A' MAXIMUM_SAMPLING_PARAMETER = 'N/A' SAMPLING_PARAMETER_INTERVAL = 4641 MINIMUM_AVAILABLE_SAMPLING_INT = 'N/A' SAMPLING_PARAMETER_UNIT = 'METER' DATA_SET_PARAMETER_NAME = 'PLANETARY RADIUS' NOISE_LEVEL = 'UNK' DATA_SET_PARAMETER_UNIT = 'METER' END_OBJECT = DSPARMINFO OBJECT = SCDSHOST INSTRUMENT_HOST_ID = 'MGN' INSTRUMENT_ID = 'RDRS' END_OBJECT = SCDSHOST OBJECT = DSREFINFO REFERENCE_KEY_ID = 'FORD1991' OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = 'Software Interface Specification' JOURNAL_NAME = 'Project Magellan SIS Document' PUBLICATION_DATE = 1991 REFERENCE_DESC = "Peter G. Ford, Global Altimetry and Radiometry Data Record, Project Magellan Software Interface Specification Document MIT-MGN-GxDR, 1991 Version 2.3, 40p." OBJECT = REFAUTHORS AUTHOR_FULL_NAME = 'Peter G. Ford' END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = SAUNDERSETAL1990 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = 'Mission Science' JOURNAL_NAME = 'Journal of Geophysical Research' PUBLICATION_DATE = 1990 REFERENCE_DESC = "Saunders, R.S., G.H. Pettengill, R.E. Arvidson, W.L. Sjogren, W.T.K. Johnson, L. Pieri, The Magellan Venus Radar Mapping Mission, Journal of Geophysical Research, 1990, Vol 95, pp. 8339-8335" OBJECT = REFAUTHORS AUTHOR_FULL_NAME = 'R. Stephen Saunders' END_OBJECT = REFAUTHORS OBJECT = REFAUTHORS AUTHOR_FULL_NAME = 'Gordon H. Pettengill' END_OBJECT = REFAUTHORS OBJECT = REFAUTHORS AUTHOR_FULL_NAME = 'Raymond E. Arvidson' END_OBJECT = REFAUTHORS OBJECT = REFAUTHORS AUTHOR_FULL_NAME = 'William T. K. Johnson' END_OBJECT = REFAUTHORS OBJECT = REFAUTHORS AUTHOR_FULL_NAME = 'Leslie J. Pieri' END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO OBJECT = DSREFINFO REFERENCE_KEY_ID = FORDETAL1992 OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = 'Mission Science' JOURNAL_NAME = 'Journal of Geophysical Research' PUBLICATION_DATE = 1992 REFERENCE_DESC = "Ford, P.G. and G.H. Pettengill, Venus Topography and Kilometer-Scale Slopes, Journal of Geophysical Research, 1992, Vol 97, pp. 13103-13114" OBJECT = REFAUTHORS AUTHOR_FULL_NAME = 'Peter G. Ford' END_OBJECT = REFAUTHORS OBJECT = REFAUTHORS AUTHOR_FULL_NAME = 'Gordon H. Pettengill' END_OBJECT = REFAUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO END_OBJECT = DATASET END