GLOALMANAC
Decoded GLONASS L1 C/A Almanac
|
Platform: |
OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7, SMART2 |
The GLONASS L1 C/A almanac reference time and week are in GPS reference time coordinates. GLONASS ephemeris information is available through the GLOEPHEMERIS log.
The OEM7 family of receivers automatically save almanacs in their Non-Volatile Memory (NVM), so creating an almanac boot file is not necessary.
The speed at which the receiver locates and locks onto new satellites is improved if the receiver has approximate time and position (SETAPPROXTIME and SETAPPROXPOS), as well as an almanac. This allows the receiver to compute the elevation of each satellite so it can tell which satellites are visible and their Doppler offsets, improving Time to First Fix (TTFF).
Message ID: 718
Log Type: Asynch
Recommended Input:
log gloalmanaca onchanged
ASCII Example:
#GLOALMANACA,USB1,0,53.0,SATTIME,2209,504978.000,02000020,ba83,16809;
24,
2209,459317.000,1,1,1,0,38099.000000000,2.399074047,0.023048661,0.000476837,-0.560765852,-2655.628906250,0.001831055,-0.000007629,
2209,424430.093,2,-4,1,0,3212.093750000,-1.309084823,0.030961245,0.002090454,-2.181895923,-2656.099609375,0.002197266,-0.000518799,
...
2209,446938.156,23,3,1,0,25720.156250000,1.249280545,0.051649013,0.000517845,1.196025646,-2656.480468750,-0.000183105,0.000041962,
2209,451304.593,24,2,1,0,30086.593750000,0.928882292,0.033564818,0.000393867,-1.955729631,-2655.910156250,-0.000183105,-0.000091553*87b68608
|
Field |
Field type |
Description |
Format |
Binary Bytes |
Binary Offset |
|
1 |
Log header |
GLOALMANAC header For information about log headers, see ASCII, Abbreviated ASCII or Binary. |
|
H |
0 |
|
2 |
#recs |
The number of GLONASS almanac records to follow. Set to zero until almanac data is available |
Long |
4 |
H |
|
3 |
week |
GPS reference week, in weeks |
Ulong |
4 |
H+4 |
|
4 |
time |
GPS reference time, in milliseconds (binary data) or seconds (ASCII data) Note: The week and time are based on the GPS scale and are computed using the N4, NA, and tλnA values. |
GPSec |
4 |
H+8 |
|
5 |
slot |
Slot number for satellite, ordinal |
Uchar |
1 |
H+12 |
|
6 |
frequency |
Frequency for satellite, ordinal (frequency channels are in the range -7 to +6) |
Char |
1 |
H+13 |
|
7 |
sat type |
Satellite type where 0 = GLO_SAT 1 = GLO_SAT_M (M type) 2 = GLO_SAT_K (K type) |
Uchar |
1 |
H+14 |
|
8 |
health |
Satellite status where 0 = OPERATIONAL 1 = MALFUNCTION |
Uchar |
1 |
H+15 |
|
9 |
TlambdaN |
GLONASS Time of ascending node equator crossing (s) |
Double |
8 |
H+16 |
|
10 |
lambdaN |
Longitude of ascending node equator crossing |
Double |
8 |
H+24 |
|
11 |
deltaI |
Correction to nominal inclination (radians)1 |
Double |
8 |
H+32 |
|
12 |
ecc |
Eccentricity |
Double |
8 |
H+40 |
|
13 |
ArgPerig |
Argument of perigee (PZ-90.02) (radians) |
Double |
8 |
H+48 |
|
14 |
deltaT |
Correction to the mean value of the Draconian period (s/orbital period)2 |
Double |
8 |
H+56 |
|
15 |
deltaTD |
Rate of change of orbital period (s/orbital period2) |
Double |
8 |
H+64 |
|
16 |
tau |
Clock offset (s) |
Double |
8 |
H+72 |
|
17 |
Next message offset = H + 4 + (#recs x 76) |
||||
|
18 |
xxxx |
32-bit CRC (ASCII and Binary only) |
Ulong |
4 |
H+4+ |
|
19 |
[CR][LF] |
Sentence terminator (ASCII only) |
- |
- |
- |