Galileo Spacecraft Pages
4. LGA Processor Overview
4.1 LGAPROC Operation
4.1.1 Configuration Files
Before running LGAPROC, the operator must create a configuration file which describes the data to be processed. The configuration file contains several lines of data in the following format:
KEYWORD = VALUE
The valid keywords and expected values are listed in Table 1 below.
|EPD_PKT||Filename of EPD SFDU packets. Multiple EPD packet files may be listed. They will be read in the order they are listed.||Y|
|AACS_PKT||Filename of AACS SFDU packets.||N|
|MAG_ASC||Filename of ASCII MAG data.||N|
|APPEND||If 'Y' then new data is appended to old files. If 'N' new files are created for all data.||N|
|COORD_CENTER||The body to be the center of coordinates. 'Jupiter' is the normal value.||N|
4.1.2 Running LGAPROC
After creating the configuration file, LGAPROC can be executed. The executable will accept the name of the configuration file as a command line parameter. If no command line parameter is specified, the program will prompt the operator for the name of the configuration file.
No output is generated during the execution of LGAPROC. Successful completion of the program is indicated the return of the command prompt without error. The operator should inspect the log files mentioned below to determine if LGAPROC encountered any problems reading the data files.
LGAPROC generates two files for each day of data processed. The first file is the archive file with record structure described in Section 3. The archive filenames are generated to match the year and day of the data contained in the files. For example, data collected during day 250 of 1996 would be stored in a file named 96250.lga. A log file is also generated corresponding to each archive file. In the above example, 96250.log would contain information about which packets LGAPROC processed. The log file will contain notation if EPD packets are out of sequence and if EPD packets cannot be matched with appropriate MAG and AACS data. No note will appear in the log file about missing MAG or AACS information if quick look files are being produced from EPD packets only.
4.2 LGAPROC Functions
The basic tasks performed by LGAPROC include the following:
**Known deficiency of this document: "Still need to include a more complete description of the processing steps in the final version of LGAPROC; description of the sfdu.h and bits.h libraries." See other documents on this website.
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Updated 12/21/04, T. Hunt-Ward