Chandrayaan-1 MRFFR Calibrated Data Record (CDR)

CDR – Calibrated Data Record

Instrument: Forerunner

PDS3 Data Set ID: CH1-ORB-L-MRFFR-4-CDR-V1.0

PDS4 Bundle: urn:nasa:pds:chand1-orb_mini_rfDOI: 10.17189/1519033

Chandrayaan-1 Mini-RF archives PDS3 to PDS4 Migration Status: Complete

For more information about Forerunner CDR products, see the CDR Data Set Description.

For more information about all Forerunner products, see the Data Product SIS.

The Forerunner (MRFFR) Calibrated Data Record (CDR) data products are Synthetic Aperture Radar (SAR) images collected by the instrument. They also contain stokes parameters files, polarization ratio files, and a browse image.

CDRs are SAR images in range and azimuth orientation with pixel values in beta naught, which have been radiometrically and polarmetrically calibrated. Each cross-product image file contains simple lines of pixels. Each pixel consists of four 4-byte floating point numbers. The first two floating point numbers are the image intensity values for the horizontal (H) and vertical (V) channel receive. The second two numbers are the real and imaginary parts of the single complex number which gives the cross power intensity image between the H & V receive. H & V represent the complex amplitudes of the horizontally and vertically polarized backscatter respectively. An asterisk (*) represents a complex conjugate of H or V. CDRs are the lowest level usable science data products.

Each science product is accompanied by a text metadata file that contains the parameters that describe the state the instrument was in at the time of data collection and location and timing information about the data set.

MRFFR CDR products have the following file names:

FSB_nnnnn_1CD_XrU_aadooo_Vz.xxx (with one detached PDS label for the two data files and one detached PDS label for the housekeeping product)

where:

F = instrument = Forerunner

S = frequency band = S-band

B = radar mode = Baseline SAR

nnnnn = orbit number in which data acquisition began, numeric range 00001…99999

R = processing level = Raw PDR

tt = file type

CD = Calibrated Data Records

HK = Instrument Housekeeping data

X = projection = N/A

r = pixel resolution bin scale in pixels per degree (ppd) and meters/pixel (mpd)

H = 128 ppd, 237 mpd

I = 256 ppd, 118 mpd

B = bit type and scaling = Byte

aa = lunar center latitude to nearest whole degree, numeric range 00…90, XX = N/A or Unknown

d = hemisphere of latitude

N = North latitude

S = South latitude

X = N/A

ooo = lunar center longitude to nearest whole degree, numeric range 000…359

z = product version number, numeric range 1…9

xxx = file extension

DAT = Unformatted binary data (e.g., raw files)

TXT = Unstructured text data (e.g., parameter files)

CSV = Comma Separated Value text files (housekeeping)

IMG = Processed image file

In ODE, CDR products have the following product IDs:

FSB_NNNNN_1CD_XRU_AADOOO_VZ