Original Document: Dave Curtis, Space Sciences Laboratory, UC Berkeley, CA 947204
Modified By: Roger Williams, Space Sciences Laboratory, UC Berkeley, CA 94720

The ISPM LAN team has broken down the data processing programming tasks among the various member institutions. Berkeley's task is to provide the front end software that reads the EDR and SEDR data tapes generated at JPL and produces a LAN archive tape. The format for this tape is specified in the LAN archive tape format definition document compiled at Fundamental Technologies by Tom Armstrong. In addition to this tape, a number of synoptic plots and an on-line data base of selected channels of LAN data are to be generated at Berkeley.

The software is constrained to be written in FORTRAN 77 in such a way as to be portable among the various institutions of the LAN team. All key member institutions of the LAN team have DEC VAX computers, but some run the VMS operating system, while others run UNIX. To achieve this goal, the bulk of the software is written in standard FORTRAN 77 with on extensions, while a few key routines are necessarily site-specific (in particular the tape I/O routines). These routines are written separately for each operating system, conforming to a common interface specification.

The bulk of this programming task has been completed, and the modules are described in an attached document. The software was written by David Curtis and Peter Harvey at Berkeley, under the UNIX operating system, and has been partially verified under VMS.

The tasks required to complete the Berkeley portion of the data processing software are described below:

1. Magnetometer validity flags in ARC header (ARCGEN program, subroutine GETBF in module bfield.f)

The Archive record header specification calls for data validity flags for the magnetometer data (record header variable BFIELD). The only available documentation on the contents of the magnetometer (HED) data in the experiment housekeeping words is contained in a letter of March 31, 1983, from George Simnett to Dr. Lanzerotti. The contents of the data words are fairly well described, but there are references to a number of data validity qualifiers that are not well described. In order to generate the data called for in the Archive header specification, a more precise definition of the HED experiment housekeeping words is necessary. Rob Gold and/or Tom Armstrong agreed to obtain this information.

2. Magnetometer uncertainty words in ARC header (ARCGEN program, subroutine GETBF in module bfield.f)

The Archive record header specification calls for data uncertainty factors for the magnetometer data (record header variable BFIELD). It has been agreed that these uncertainty factors should contain the 1-bit quantization level of the data item. This factor has not yet been implemented (currently the uncertainty factor is set to zero).

3. Ephemeris, Orientation, and Transformation data in Archive header (ARCGEN program, module oa.f; OAGEN program)

The Archive record header specification calls for a number of variables associated with orbit and attitude information (EPHEM, AXIS, TRANS). These factors are derived from information contained in an auxiliary SEDR tape generated at JPL. The program OAGEN reads this tape and extracts the necessary information into a database file called OA.DAT. Note that the OAGEN program is not yet documented in the data production software module descriptions. The routines in the module oa.f read this file and compute the required information for a selected time. Work on this module was in progress when work on ISPM was suspended. A routine called 'findoa' needs to be written (finds the data point in the OA.DAT file that is closest to a specified time and interpolates to get the best estimate of the SEDR O&A data). The oa module must then be tested, and then integrated into the ARCGEN program. The routine GETOA should be called by LANAH in archdr.f.

4. Housekeeping data in Archive Header (ARCGEN program, subroutine LANAH in module archdr.f)

The Archive record header specification calls for a block of housekeeping data (HOUSE). The contents of this block have not yet been defined. R. Gold agreed to provide this information.

5. Pitch Angles in the Archive Rate Block (ARCGEN program, subroutine GETRH in module rates.f)

The Archive Rate Block specification calls for pitch angles and look directions of the detectors (PA, PB, etc.). This information can be computed from the magnetometer information and the orbit and attitude information in the record header, together with the detector look direction information which should be included in the instrument description file. This has not yet been done.

6. Synoptic file plotter, time axis (ARCSYN program, module synplt.f)

The synoptic file plot routines in ARCSYN have not yet been documented. In addition, the time axis of the plots is in units of fractional hours. T. Armstrong agreed to provide a better time axis routine with rational tic marks.

Relevant Documents:

LAN Experiment Data System: Performance and Interface Specification," D.R. Guynn

"EDR Software Interface Specification," JPL 628-306 ICD ISPM 2sb

"SEDR Software Interface Specification," JPL 628-306 ICD ISPM 2sc

ISPM LAN Archive Tape definition documents (T. P. Armstrong, Fundamental Technologies)
Record Header Definition, 1/25/85
Rate Block Definition, 1/25/85
MFSA Block Definition, 5/23/85
PHA Block Definition, 5/23/85

ISPM LAN Data Production Software Module Descriptions
ARCGEN, 11/15/85
SYNCHK, 8/20/85
STATMRG, 8/20/85
ARCSTAT, 8/20/85
ARCLOG, 8/20/85
ARCSYN, 8/20/85
ARCDUMP, 8/20/85

"ISPM LAN Coordinate Systems and Transformations," 12/11/85, D.W. Curtis, U.C. Berkeley

Letter from R. Gold to Distribution, 1/21/85; LAN-082-85, Validity checks of LAN Data Stream

Letter from George Simnett to L. Lanzerotti, 3/31/83, Magnetometer (HED) experiment housekeeping contents description

Letter from R. Gold to D. Curtis, 9/5/85, LAN Analog housekeeping calibrations

Letter from R. Gold to L. Lanzerotti, 1/20/86; LAN # 087-86, LAN Look Directions

• A5.1 ARCGEN
• A5.2 ARCDUMP
• A5.3 ARCLOG
• A5.4 ARCSTAT
• A5.5 ARCSYN
• A5.6 STATMRG
• A5.7 SYNCHK
• LAN Pulse Height Archive Block Updates

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