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Appendices
Test Bed Receiver Subsystem Addendum – Rev 1 43
GEPA/B EPHEMERIS INFORMATION
GLONASS ephemerides are referenced to the Parametry Zemli 1990 (PZ-90) geodetic datum, and GLONASS ephemeris
information is available through the GEPA/B log. GLONASS coordinates are reconciled internally through a position
filter and output to WGS84. Refer to the SVDA/B log in the
MiLLennium Command Descriptions Manual for information
on WGS84.
GEPA
Structure:
$GEPA week
seconds ephweek ephtime time offset
svid
freq issue health posX posY posZ
velX
velY velZ LSAccX LSAccY LSAccZ tau
gamma
tk age flags *xx [CR][LF]
Field #
Field
Description Example
1
$GEPA Log Header $GEPA
2 Week GPS Week of log output 991
3 Seconds GPS Time of log output 496487
4 EphWeek Reference week of ephemeris (in GPS time) 991
5 EphTime Reference time of ephemeris (in GPS time) 495913
6 Time
offset
Integer seconds between GPS and GLONASS Time + implies GLONASS
ahead of GPS
107871
7 SVID Slot number for satellite 4
8 Freq Frequency number for satellite 12
9 Issue 15-minute interval number corresponding to ephemeris reference time 83
10 Health Ephemeris Health (0 = GOOD, 1 = BAD) 0
11 PosX X coordinate for satellite at reference time (PZ90), in meters -2.102581933593754E+007
12 PosY Y coordinate for satellite at reference time (PZ90), in meters -1.216645166015627E+007
13 PosZ Z coordinate for satellite at reference time (PZ90), in meters 7.7982763671875110E+006
14 VelX X coordinate for satellite velocity at reference time (PZ90), in meters/s -9.655075073242192E+002
15 VelY Y coordinate for satellite velocity at reference time (PZ90), in meters/s -5.014476776123048E+002