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142 MiLLennium Command Descriptions Manual
GPALM Almanac Data
This log outputs raw almanac data for each satellite PRN contained in the broadcast message. A separate record is
logged for each
PRN, up to a maximum of 32 records. Following a GPSCard reboot, no records will be output until
new broadcast message data is received from a satellite. It takes a minimum of 12.5 minutes to collect a complete
almanac following GPSCard boot-up. (The almanac reported here has no relationship to the NovAtel $
ALMA
almanac injection command. Following a cold start, the log will output null fields until a new almanac is collected
from a satellite.)
Structure:
Example:
$GPALM,17,17,28,653,00,3EAF,87,0D68,FD30,A10CAB,6EE732,525880,6DC5A8,009,
005*37[CR][LF]
➀ Variable length integer, 4-digits maximum from (2) most significant binary bits of Subframe 1, Word 3
reference Table 20-I, ICD-GPS-200, Rev. B, and (8) least significant bits from subframe 5, page 25, word 3
reference Table 20-I, ICD-GPS-200, Rev. B, paragraph 20.3.3.5.1.7
➁ Reference paragraph 20.3.3.5.1.3, Table 20-VII and Table 20-VIII, ICD-GPS-200, Rev. B
➂ Reference Table 20-VI, ICD-GPS-200, Rev. B for scalingfactors and units.
To obtain copies of ICD-GPS- 200, see Appendix F, Standards and References, for address information.
$GPALM
# msg
msg # PRN GPS wk SV hlth ecc
alm ref time incl angle omegadot rt axis
omega
long asc node
M
o
a
f1
*xx
[CR][LF]
Field Structure Field Description Symbol
Exam-
ple
1 $GPALM Log header $GPALM
2 # msg Total number of messages logged x.x 17
3 msg # Current message number x.x 17
4 PRN Satellite PRN number, 01 to 32 xx 28
5 GPS wk
GPS reference week number
➀
x.x 653
6 SV hlth
SV health, bits 17-24 of each almanac page
➁
hh 00
7 ecc
e, eccentricity
➂
hhhh 3EAF
8 alm ref time
toa, almanac reference time
➂
hh 87
9 incl angle
(sigma)
i
, inclination angle
➂
hhhh OD68
10 omegadot
OMEGADOT, rate of right ascension
➂
hhhh FD30
11 rt axis
(A)
1/2
, root of semi-major axis
➂
hhhhhh A10CAB
12 omega
omega, argument of perigee
➂
hhhhhh 6EE732
13 long asc node
(OMEGA)
o
,longitude of ascension node
➂
hhhhhh 525880
14 M
o
Mo, mean anomaly
➂
hhhhhh 6DC5A8
15 a
f0
af0, clock parameter
➂
hhh 009
16 a
f1
af1, clock parameter
➂
hhh 005
17 *xx Checksum *hh *37
18 [CR][LF] Sentence terminator [CR][LF]