C-Nav 2050, Руководство пользователя

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2050 User Guide
D.1 ALM NMEA Sentence
GPS Almanac Data
The ALM sentence provides GPS week number, satellite health and the complete almanac
data for one satellite. Multiple messages may be transmitted for each satellite.
Example:
$GPALM,32,1,01,1273,00,2A53,7B,1845,FD59,A10C1B,75D0A3,BB4C39,0FAD97,16C,000*4B
FIELD Description
1 Total Number of messages
2 Message Number
3 Satellite PRN Number – 01 thru 32
4 GPS Week Number
5 SV Health – bits 17 thru 24 of each almanac page (‘00’ = healthy)
6 Eccentricity - e
7 Almanac Reference Time – t
oa
8 Inclination Angle – (sigma)
i
9 Rate of Right Ascension - OMEGADOT
10 Root of Semi-Major Axis - root(A)
11 Argument of Perigee - OMEGA
12 Longitude of Ascention Node – (OMEGA)
0
13 Mean Anomaly – M
0
14 Clock Parameter – af
0
15 Clock Paramater – af
1
Table D. 2 ALM Sentence Fields
Note – Reference ICD-GPS-2000, Rev.B
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