GPALM

Almanac data

Platform:

OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7, SMART2

This log outputs raw almanac data for each GPS satellite PRN contained in the broadcast message. A separate record is logged for each PRN, up to a maximum of 32 records. GPALM outputs these messages without waiting for a valid almanac. Instead, it uses a UTC time, calculated with default parameters. In this case, the UTC time status (see the TIME log) is set to WARNING since it may not be one hundred percent accurate. When a valid almanac is available, the receiver uses the real parameters. UTC time is then set to VALID. It takes a minimum of 12.5 minutes to collect a complete almanac following receiver boot-up. In the case of a GLONASS capable receiver, the UTC offset can be determined once the GLONASS ephemeris is decoded, which takes about 50 seconds. If an almanac was stored in NVM, the stored values are reported in the GPALM log once time is set on the receiver.

To obtain copies of ICD-GPS-200, refer to https://www.gps.gov/technical/icwg/.

Message ID: 217

Log Type: Asynch

Recommended Input:

log gpalm onchanged

Example:

$GPALM,30,01,01,2210,00,617b,0f,1da7,fd70,a10d0a,24de91,6fe696,16263f,17c,ffe*7B

$GPALM,30,02,02,2210,00,a752,0f,0f5f,fd56,a10cf7,c62dda,6c306a,1c751c,d53,000*7F

$GPALM,30,03,03,2210,00,21ef,0f,1464,fd63,a10c9d,26d19c,9a02d6,e8f3d8,eff,ffc*20

$GPALM,30,04,04,2210,00,0ed5,0f,0bfc,fd40,a10c67,871978,c614e7,5cff7f,f51,001*26

$GPALM,30,05,05,2210,00,30d6,0f,0bf0,fd56,a10d59,2996db,98511a,8266e6,faa,000*2B

$GPALM,30,06,06,2210,00,150b,0f,1d37,fd6d,a10d81,dd08a4,6f9046,1f9de5,13f,004*79

$GPALM,30,07,07,2210,00,83b7,0f,059e,fd5c,a10cf2,a38e0f,ef9113,faf04e,152,000*7D

$GPALM,30,08,08,2210,00,3d03,0f,0da3,fd22,a10da6,06d382,43d119,6f02ae,fb9,000*76

$GPALM,30,09,09,2210,00,1113,0f,0770,fd39,a10bfc,4c6129,c3e4b9,844e81,e9f,001*7C

$GPALM,30,10,10,2210,00,3e48,0f,1443,fd65,a10d0e,9a5e76,99e60d,c36848,e4c,ffc*2A

...

$GPALM,30,21,22,2210,00,6d60,0f,0c0f,fd41,a10cff,b484ba,c80d8d,69e9f1,110,002*75

$GPALM,30,22,23,2210,00,118d,0f,1111,fd62,a10d46,7a73b2,98de21,f78a52,fe9,fff*20

$GPALM,30,23,24,2210,00,662b,0f,fad0,fd4c,a10d14,212fb6,ec22c7,22a913,0fc,ffe*24

$GPALM,30,24,25,2210,00,5625,0f,0983,fd44,a10d05,28daa2,19bb67,d5b628,155,001*71

$GPALM,30,25,26,2210,00,38d6,0f,fd0b,fd36,a10d99,0fd6f2,17bfe3,ba7af2,0d8,001*7E

$GPALM,30,26,27,2210,00,5671,0f,1355,fd2a,a10cd2,1bbd7f,44a393,70647e,0d5,002*75

$GPALM,30,27,29,2210,00,119e,0f,18e8,fd35,a10d41,5beea1,47bfe9,7518fe,de5,fff*2A

$GPALM,30,28,30,2210,00,2fa3,0f,fbf2,fd4d,a10dc1,923e8f,f00c20,fa7e58,dd6,000*2E

$GPALM,30,29,31,2210,00,5578,0f,085d,fd5d,a10d86,0fe442,f05163,e7e443,f46,000*2F

$GPALM,30,30,32,2210,00,30d7,0f,09ed,fd3d,a10c3f,a2d321,c45da6,8b29e1,f7a,ffe*70

See the The NMEA (National Marine Electronics Association) has defined standards that specify how electronic equipment for marine users communicate. GNSS receivers are part of this standard and the NMEA has defined the format for several GNSS data logs otherwise known as 'sentences'. that applies to all NMEA logs.

Field	Structure	Description	Symbol	Example
1	$GPALM	Log header		$GPALM
2	# msg	Total number of messages logged. Set to zero until almanac data is available	x.x	17
3	msg #	Current message number1	x.x	17
4	PRN	Satellite PRN number: GPS = 1 to 32	xx	28
5	GPS wk	GPS reference week number	x.x	653
6	SV hlth	SV health, bits 17-24 of each almanac page2	hh	00
7	ecc	e, eccentricity3	hhhh	3EAF
8	alm ref time	to a almanac reference time ³	hh	87
9	incl angle	(sigma)i, inclination angle ³	hhhh	OD68
10	omegadot	OMEGADOT, rate of right ascension ³	hhhh	FD30
11	rt axis	(A)^1/2, root of semi-major axis ³	hhhhhh	A10CAB
12	omega	omega, argument of perigee ³	hhhhhh	6EE732
13	long asc node	(OMEGA)°, longitude of ascension node ³	hhhhhh	525880
14	Mo	Mo, mean anomaly ³	hhhhhh	6DC5A8
15	af0	af0, clock parameter ³	hhh	009
16	af1	af1, clock parameter ³	hhh	005
17	*xx	Check sum	*hh	*37
18	[CR][LF]	Sentence terminator		[CR][LF]