BDSALMANAC
Decoded BDS Almanac
|
Platform: |
OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7, SMART2 |
This log contains the decoded BeiDou B1I almanac parameters, with the parity information removed and appropriate scaling applied. Multiple messages are transmitted, one for each SV almanac collected. For more information about almanac data, refer to the BDS Signal Specification.
The OEM7 family of receivers automatically save almanacs in their Non-Volatile Memory (NVM), so creating an almanac boot file is not necessary.
Message ID: 1584
Log Type: Asynch
Recommended Input:
log bdsalmanaca onchanged
ASCII Example:
#BDSALMANACA,USB1,58,66.0,SATTIME,2209,495392.000,02000020,24ad,16809;1,853,
233472,6493.366211,3.9148330688e-04,2.140348862,1.199588705,-2.642467663,
6.62884755e-10,1.3200623733e-02,1.783371e-04,4.36557e-11,0*47ce1f59
#BDSALMANACA,USB1,57,66.0,SATTIME,2209,495422.000,02000020,24ad,16809;2,853,
233472,6493.407715,1.2860298157e-03,-1.063963232,-3.106212600,-2.469847262,
2.85726187e-10,3.2794831454e-02,4.005432e-05,-4.00178e-11,0*8a6f2da6
#BDSALMANACA,USB1,56,66.0,SATTIME,2209,495452.000,02000020,24ad,16809;3,853,
233472,6493.317871,8.8787078857e-04,0.016723986,2.822887922,-2.736275307,
4.11445710e-10,3.2818799903e-02,-5.550385e-04,7.27596e-12,0*d002a7ff
...
#BDSALMANACA,USB1,2,66.0,SATTIME,2209,494348.000,02000020,24ad,16809;60,853,
233472,6493.458496,4.3869018555e-04,1.681354547,2.010414773,2.163612865,
2.25152236e-09,3.6605814973e-02,-9.536743e-07,0.00000,58*0b0eeddc
#BDSALMANACA,USB1,1,66.0,SATTIME,2209,494378.000,02000020,24ad,16809;61,853,
233472,6493.341309,5.9413909912e-04,-0.385926122,-0.842142719,1.330163202,
2.12580283e-09,2.6886608575e-02,0.000000,0.00000,58*0db11f92
#BDSALMANACA,USB1,0,66.0,SATTIME,2209,474248.000,02000020,24ad,16809;62,853,
417792,6553.599609,1.2499809265e-02,-1.256637361,-1.256637361,1.256636987,
5.99202102e-07,1.5707723583e-01,7.810593e-04,-1.49157e-09,100*5633ace5
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).
|
Field |
Field Type |
Description |
Format |
Binary Bytes |
Binary Offset |
|
1 |
Log header |
BDSALMANAC header For information about log headers, see ASCII, Abbreviated ASCII or Binary. |
|
H |
0 |
|
2 |
satellite ID |
Satellite ID/ranging code |
Ulong |
4 |
H |
|
3 |
week |
Week number in BeiDou time (BDT) since the BeiDou system time start epoch (January 1, 2006) |
Ulong |
4 |
H+4 |
|
4 |
toa |
Time of almanac (s) |
Ulong |
4 |
H+8 |
|
5 |
RootA |
Square root of semi-major axis (sqrt(m)) |
Double |
8 |
H+12 |
|
6 |
ecc |
Eccentricity (dimensionless) |
Double |
8 |
H+20 |
|
7 |
ω |
Argument of perigee (radians) |
Double |
8 |
H+28 |
|
8 |
M0 |
Mean anomaly at reference time (radians) |
Double |
8 |
H+36 |
|
9 |
Ω |
Longitude of ascending node of orbital of plane computed according to reference time (radians) |
Double |
8 |
H+44 |
|
10 |
|
Rate of right ascension (radians/s) |
Double |
8 |
H+52 |
|
11 |
δi |
Correction of orbit reference inclination at reference time (radians) |
Double |
8 |
H+60 |
|
12 |
a0 |
Constant term of clock correction polynomial (s) |
Double |
8 |
H+68 |
|
13 |
a1 |
Linear term of clock correction polynomial (s/s) |
Double |
8 |
H+76 |
|
14 |
health |
Satellite health information |
Ulong |
4 |
H+84 |
|
15 |
xxxx |
32-bit CRC (ASCII and Binary only) |
Hex |
4 |
H+88 |
|
16 |
[CR][LF] |
Sentence terminator (ASCII only) |
- |
- |
- |
