MGN RDRS Full-Resolution Basic Image Data Record (FBIDR)

FBIDR – Full-Resolution Basic Image Data Record

PDS Data Set ID: MGN-V-RDRS-5-BIDR-FULL-RES-V1.0DOI: 10.17189/1522529

For more information about RDRS FBIDR products, see the FBIDR Data Set Description and FBIDR Product SIS.

The Radar System (RDRS) Full-Resolution Basic Image Data Record (FBIDR) data products consist of synthetic aperture radar (SAR) image data acquired along one orbit. Pixel widths are 75 m. Data are presented as 8-bit pixel brightness values where the brightness is in proportion to the scaled radar backscatter cross section. Scaling is accomplished by dividing the radar cross section value for each pixel by the value estimated from the Muhleman Law for the mid-range point incidence angle, converting the ratio to decibels, and scaling to a 1 to 251 output range. The 1 value corresponds to -20 dB and 251 to +30 dB, with a linear quantization of 0.2 dB in between. Data have at least 4 looks.

FBIDRs are presented as image files containing two 2-byte VAX integers at the beginning of each line. The first integer specifies the pixel offset to (# bytes to but NOT including) the first valid pixel; the second specifies a pointer to (# bytes to AND including) the last valid pixel. The remainder of the line consists of scaled backscatter cross section values.

Regions within 89 degrees of the equator have FBIDRs in sinusoidal equal area projection; FBIDR data located more than 80 degrees from the equator are also in oblique sinusoidal equal area projection. For the sinusoidal equal area projection, the origin is at 0 degrees latitude and the central meridian is the sub-spacecraft longitude at the equator, adjusted to the nearest multiple of 75 m, relative to a pixel centered at 0 degrees longitude.

RDRS FBIDR product subdirectories have the following directory names:

Fnnnn_x

where:

nnnn = 4-digit decimal number denoting the Magellan Project-assigned orbit number

x = 1-digit decimal number denoting the Project-assigned version of the FBIDR product for the orbit

In ODE, FBIDR products, which include the files in the table below, have the following product IDs:

F-BIDR.0NNNN;0X

Within each FBIDR product subdirectory, the following files appear. All files except the ERR file appear along with their corresponding PDS labels.

File Name	File Contents
ERR_nnnn.TXT	List of discrepancies for this FBIDR between the SIS and the FBIDR data files
FILE_01	Summary FBIDR volume information
FILE_02	Orbit header
FILE_03	EDR data quality summary
FILE_04	S/C ephemeris file
FILE_05	SCLK/SCET conversion coefficients
FILE_06	DSN monitor records
FILE_07	Quaternion pointing coefficients
FILE_08	Processing bandwidth
FILE_09	Decommutation and decalibration data
FILE_10	Engineering data
FILE_11	Radar burst header records
FILE_12	Per-orbit parameters
FILE_13	Image data in oblique sinusoidal projection
FILE_13.AUX	Index file for FILE_13
FILE_14	Processing parameters for oblique sinusoidal data
FILE_15	Image data in sinusoidal projection
FILE_15.AUX	Index file for FILE_15
FILE_16	Processing parameters for sinusoidal data
FILE_17	Processed radiometric data
FILE_18	Cold-sky calibration results
FILE_19	Processing monitor record
FILE_20	Additional FBIDR volume information