Voyager LECP Pages
February 2, 1982
TO: Voyager LECP Team Members
FROM: J. F. Carbary
SUBJECT: GSFC MAG Data and Merged NAV-MAG Data
The GSFC magnetometer team has recently made available to us the Saturn encounter MAG data. The data have a time resolution of 48S and cover the time intervals:
The MAG data are given in the spacecraft payload (PLD) system - not the usual heliographic (RTN) system. The experimenters must take care to make the necessary transformations. The PLD data are in the same positions on a MAG tape as the usual RTN data were.
In addition, tapes have been created which contain merged navigation (NAV) and MAG data at a 48S time resolution. These NAVMAG tapes are FB, 1600 BPI and have the following record format:
|1||I*2||YY||2 digit year|
|2||I*2||DDD||Day of year (Jan 1 = 1)|
|3||I*2||HH||Hour of day|
|4||I*2||MM||Minute of hour|
|5||I*2||SS||Second of minute|
|7-10||R*8||TSEC||Seconds since 1977.000.00|
|11-16||R*4||R(3)||Spacecraft X,Y,Z in STN frame* in RS**|
|17-22||R*4||B(3)||Magnetic field Bx, By, Bz in STN frame* in g|
|23-40||R*4||TM(3,3)||Transform matrix from LECP frame*** to STN frame*|
|41-42||R*4||LON||Spacecraft SLS longitude**** in degrees|
|43-44||R*4||LAT||Spacecraft latitude in degrees|
|*||The STN frame is similar to the solar ecliptic frame used at earth. In the STN system, Z points along the spin axis of Saturn, X points sunward in the meridian defined by Z and the planet-sun line, and Y completes the RH system.|
|**||1 RS = 60000 km. Users may wish to convert to 1 RS = 60330 km, in which case the conversion factor is 0.99453.|
|***||The LECP frame is the scan frame of the instrument with Z along the stepper axis, X along the centerline of sector 8, and Y along the centerline of sector Z.|
|****||Desch and Kaiser, Geophys. Res. Lett., 8, 253, 1981.|
|DEC compatible software is available to read and average these tapes.|
NAV-MAG File Format
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Last modified 5/12/05, Tizby Hunt-Ward
Original page by I. Robertson