urn:nasa:pds:magellan_arcdr:data_radiometry:rdf02007_1 1.0 1.20.0.0 Product_Observational 2024-01-29 1.0 Initial PDS4 version 1991-04-25T04:33:05Z 1991-04-25T05:04:53Z Magellan Mission urn:nasa:pds:context:investigation:mission.magellan data_to_investigation Magellan Host urn:nasa:pds:context:instrument_host:spacecraft.mgn is_instrument_host Radar System for Magellan Instrument urn:nasa:pds:context:instrument:mgn.rdrs is_instrument Venus Planet urn:nasa:pds:context:target:planet.venus data_to_target ARCDR 1 1 2007 Mapping Cycle 1 mg_2009 1991-04-25T04:33:05Z 1991-04-25T05:04:53Z Center 89.1439 -34.3404 121.5343 305.3940 rdf02007_1.dat 1991-10-04T15:09:43.000Z Created with ARCDR processing software version 02 Radiometry_File Radiometry_File 0 2410 This file contains binary records describing, in time order, each radiometer footprint measured during an orbit of the Magellan radar mapper 22 8 264 SFDU 1 1 ASCII_String 20 The SFDU identifies the label and length of the Standard Format Data Unit (SFDU). Rad_Number 2 21 SignedLSB4 4 The rad_number element provides the number assigned to the burst header that contains the radiometer measurement referenced by this element. Flag 3 25 UnsignedLSB4 4 The Flag element identifies processing flag fields. Each bit in the Flag element has its own meaning and can be combined bitwise. See the ARCDR SIS Table 5-9 for a list of values and their meanings. Flag2 4 29 UnsignedLSB4 4 Additional flag fields (unused). Spacecdraft_Epoch_TDB_Time 5 33 IEEE754LSBDouble 8 The rad_spacecraft_epoch_tdb_time element provides the ephemeris time at which the radiometry measurement was made. 1 3 1 0 41 24 Spacecraft_Position_Vector 1 1 IEEE754LSBDouble 8 km The spacecraft_position_vector element provides spacecraft position at radiometry spacecraft_epoch_tdb_time, relative to the Venus center of mass, expressed in inertial coordinates in the J2000 coordinate system. 2 3 1 0 65 24 Spacecraft_Velocity_Vector 1 1 IEEE754LSBDouble 8 km/s The spacecraft_velocity_vector element provides the spacecraft velocity at radiometry spacecraft_epoch_tdb_time, relative to the Venus center of mass, expressed in inertial coordinates in the J2000 coordinate system. Footprint_Longitude 6 89 IEEE754LSBSingle 4 degree The footprint_longitude (VBF85) element provides the crust-fixed longitude, at spacecraft_epoch_tdb_time, of the intersection of the antenna boresight and the planetary surface (a sphere of radius average_planetary_radius). Footprint_Latitude 7 93 IEEE754LSBSingle 4 degree The footprint_latitude (VBF85) element provides the crust-fixed latitude, at spacecraft_epoch_tdb_time, of the intersection of the antenna boresight and the planetary surface (a sphere of radius average_planetary_radius element). Along_Track_Footprint_Size 8 97 IEEE754LSBSingle 4 km The along_track_footprint_size element provides the along-track dimension of the intersection of the SAR antenna (3dB one-way attenuation) cone with a sphere of radius average_planetary_radius. Cross_Track_Footprint_Size 9 101 IEEE754LSBSingle 4 km The cross_track_footprint_size element provides the cross-track footprint dimension of the intersection of the SAR antenna (3dB one-way attenuation) cone with a sphere of radius average_planetary_radius. 3 2 1 0 105 8 SAR_Footprint_Size 1 1 IEEE754LSBSingle 4 km The sar_footprint_size element provides the approximate diameter of the surface footprint represented by the SAR backscatter values that are provided by the sar_average_backscatter element. 4 2 1 0 113 8 SAR_Average_Backscatter 1 1 IEEE754LSBSingle 4 dB The sar_average_backscatter element provides a pair of running averages of SAR image pixel values, sar_average_backscatter[0] taken from pixels lying westward of the antenna boresight, and sar_average_backscatter[1] taken from pixels lying to the east of it. Incidence_Angle 10 121 IEEE754LSBSingle 4 degree The incidence_angle element provides the angle between the local vertical and the spacecraft direction, measured at the center of the radiometer footprint at spacecraft_epoch_event_time. Brightness_Temperature 11 125 IEEE754LSBSingle 4 K The brightness_temperature element provides the planet brightness temperature, derived from the planet_reading_system_temp after correcting for antenna efficiency and side-lobe gain. Average_Planetary_Radius 12 129 IEEE754LSBSingle 4 km The average_planetary_radius element provides the planetary radius of the radiometer footprint, used to compute footprint_longitude and footprint_latitude, and also surface_temperature and atmospheric corrections to surface_emissivity. Planet_Reading_System_Temp 13 133 IEEE754LSBSingle 4 K The planet_reading_system_temp element provides the raw radiometer reading, when switched into the SAR antenna, converted to equivalent noise temperature. Assumed_Warm_Sky_Temperature 14 137 IEEE754LSBSingle 4 K The assumed_warm_sky_temperature element provides the temperature assumed for the dominant portion of 'sky' reflected by the radiometer footprint, including atmospheric absorption and emission. Rad_Receiver_System_Temp 15 141 IEEE754LSBSingle 4 K The rad_receiver_system_temp element provides the receiver input radiometer reading, converted to equivalent noise temperature. This is the difference between raw_rad_antenna_power and raw_rad_load_power, converted to equivalent noise temperature and compensated for changes in receiver gain and temperature. Surface_Emission_Temperature 16 145 IEEE754LSBSingle 4 K The surface_emission_temperature element provides the temperature assumed for the planetary surface covered by the radiometer footprint, derived by correcting brightness_temperature for atmospheric emission and absorption. Surface_Emissivity 17 149 IEEE754LSBSingle 4 The surface_emissivity element provides the surface microwave emissivity, calculated by dividing (surface_emission_temperature - assumed_warm_sky_temperature) by (physical_surface_temperature - assumed_warm_sky_temperature). 5 18 1 0 153 72 Partials 1 1 IEEE754LSBSingle 4 The rad_partials_group element provides the partials of the footprint_latitude, the footprint_longitude, and the average_planetary_radius elements with respect to the spacecraft_position_vector and spacecraft_velocity_vector elements. Rad_Emissivity_Partial 18 225 IEEE754LSBSingle 4 km**(-1) The rad_emissivity_partial element provides the partial derivative of surface_emissivity with respect to average_planetary_radius. Surface_Temperature 19 229 IEEE754LSBSingle 4 K The surface_temperature element provides the physical surface temperature of the radiometer footprint, calculated from average_planetary_radius and the project-adopted atmospheric model. Raw_Rad_Antenna_Power 20 233 IEEE754LSBSingle 4 The raw_rad_antenna_power element provides the radiometer noise power when the receiver is connected to the SAR antenna. It is corrected for systematic errors resulting from leakage of the altimeter signal. Raw_Rad_Load_Power 21 237 IEEE754LSBSingle 4 The raw_rad_load_power element provides the radiometer noise power when the receiver is connected to a load at a known temperature. It is averaged over as many as 10 successive measurements and corrected for systematic errors resulting from leakage of the altimeter signal. 6 2 1 0 241 2 Alt_Skip_Factor 1 1 UnsignedByte 1 The alt_skip_factor elements provide the values of altimeter skip factor taken from the radar burst header. alt_skip_factor[0] pertains to the measurement of raw_rad_antenna_power and alt_skip_factor[1] to raw_rad_load_power. 7 2 1 0 243 2 Alt_Gain_Factor 1 1 UnsignedByte 1 The alt_gain_factor elements provide the values of altimeter gain factor taken from the radar burst header. alt_gain_factor[0] pertains to the measurement of raw_rad_antenna_power and alt_gain_factor[1] to raw_rad_load_power. Alt_Coarse_Resolution 22 245 SignedLSB4 4 The alt_coarse_resolution element provides the altimeter coarse time resolution factor taken from the radar burst header in which the raw_rad_antenna_power was reported. 8 16 1 0 249 16 Spare 1 1 UnsignedByte 1 Spare bytes.