getccsds output-file-1 output-file-2 ... on_pass_disk = yes or no input_file = input CADU file name (only if on_pass_disk=no) satellite = satellite name (only if on_pass_disk=no) reed_solomon = yes or no (see Notes) vcid_name = name of virtual channel sensor (such as modis or airs) vcid_number = number of virtual channel (only if vcid_name=blank) file_1_apids = ids of application packets to put in output-file-1 file_2_apids = ids of application packets to put in output-file-2 ...
getccsds reads 1024-byte CADU framed data and extracts CCSDS application packet data. A CCSDS data stream can contain data from a number of virtual channels, each with its own identifier (VCID); getccsds can only extract application packets from one virtual channel at a time. Virtual channels normally correspond to satellite sensors. Any given virtual channel may have one or more types of application packets; these types are distinquished by packet id (APID).
Each satellite has its own CCSDS configuration file, which relates virtual channels to their application packets. These configuration files are stored as $SATDATA/satellite-name/ccsds_config. The following is the CCSDS configuration file for EOS Terra-1:
# Name VCid APid MinLen MaxLen NumLens # If there is exactly one valid length, NumLens=1, MaxLen=MinLen # If there are two valid lengths, NumLens=2, MaxLen > MinLen ################################################################
modis 42 64 276 642 modis 42 127 276 642
In this example, the only virtual channel is "modis" (VCid=42). There are two packet types (APid=64 and APid=127). Each of these packet types have two possible packets sizes (276 or 642 bytes).
The reed_solomon parameter enables Reed-Solomon decoding. There is a significant tradeoff between processing speed and the potential extra data quality offered by Reed-Solomon bit error correction. Basically, reed_solomon=yes runs about 10 times slower than reed-solomon=no, and has diminishing benefit once the satellite is well above the horizon.
getccsds replaces framesx for Terra-1 and Aqua-1 application processing.
Last Updated: $Date: 2001/10/29 19:38:18 $