Galileo Spacecraft Pages
Appendix C. Magnetometer Subsystem
Table of Contents:
Source: Document 625-610, revision dated 2/16/83
The MAG EDR science record is designed to a RIM cycle containing 91 minor frames. Each minor frame corresponds to a MOD 91 count. The Mag record shall be placed onto the MAG science EDR along with AACS records in time order. The logical record structure is diagrammed in Figure 1.
Figure 1. MAG Record.
(17 32-bit words)
(54 32-bit words)
(455 32-bit words)
Processing Start/Stop. Refer to Subsection 5.2* (see below).
Record Buildup. Mag science record buildup shall proceed with the extraction from the appropriate bit locations from minor frames 1 through 91 of each RIM cycle. Subsection 5.2* defines the basic data extraction procedure.
Record Header. The MAG record shall receive a standard record header (refer to Section 4). (Ed. note: Section 4 is incorporated into this handbook as Appendix B, SEDR Files.)
Record Subheader. The MAG subheader contains a standard subheader which contains selected engineering measurements in DN extracted from the engineering packet of the LRS data block (channels from the fixed engineering data). Refer to Figure 5-1 on page 5-3 (figure incorporated below).
Standard Subheader Format:
Data Block. The MAG data block contains data extracted from bits 2880 through bits 3039 of each minor frame from the golay compressed LRS data block of the input SDR record. Specified word locations shall be maintained within the data block. Refer to Figure 2 below for data block format and GLL-3-280 Appendix A (not available on this website) for detailed definition of the data fields.
Figure 2. MAG Data Block Format
EDRGEN shall extract the AACS, science and science-related engineering channels for each LRS minor frame. EDRGEN shall then build individual experiment records and AACS records by combining all minor frames corresponding to a RIM cycle (91 minor frame) placing the start time of the first minor frame into the record header and appending SCET, golay correction flags and data presence indicator flags as indicated in Section 4. An accumulation of summary data shall be performed with the summary of each EDR tape being provided.
EDRGEN shall extract data from the LRS frames using the spacecraft clock (SCLK) count to control the extraction process. The following criteria are to be applied to SCLK count for each LRS minor frame:
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Updated 10/4/04, T. Hunt-Ward