NavCom Sapphire Rev.J - Manual (Page 259)

Sapphire Technical Reference Manual Rev. J
259
2.3 ALM1B (Version 1; v1.0.0.4) (Binary)
SF-3050 Sapphire SF-3040
From a cleared memory without an almanac present, it takes about 13 minutes after satellite
lock to obtain and display complete almanac information. With an almanac present, it takes only
a matter of seconds.
Almanac data for GPS, GLONASS, and GALILEO are available to be output and each satellite
type has its own data format.
The format of this binary message is defined in Table 105.
Table 105: ALM1B Binary Message Data
Data Item Data Type Section
Satellite type (-1=NONE, 0=GPS,
1=GALILEO, 2=SBAS, 3=GLONASS)
U08
Almanac data 2.3.1 to 2.3.4
2.3.1 GPS Almanac
Table 106 lists the body of the GPS ALM1B message. The length of this message is 862
bytes, including 853 bytes for the message body and 9 bytes for the message header.
Table 106: GPS ALM1B Binary Message Data
Data Item (Message Body: 853 Bytes) Data Type
GPS week of collection U16
GPS millisecond of collection U32
Almanac reference week U16
Almanac reference time, second-of-week U32
Almanac source prn U08
Subframe for SV ID 1 (almanac data for SV 1) 24 bytes
Subframe for SV ID 2 (almanac data for SV 2) 24 bytes
… …
Subframe for SV ID 32 (almanac data for SV 32) 24 bytes
Subframe for SV ID 51 (SV health data for SV 1 through 24, the almanac
reference time, the almanac reference week number)
24 bytes
Subframe for SV ID 56 (ionospheric and UTC data) 24 bytes
Subframe for SV ID 63 (A-S flags/SV configurations for 32 SV's, plus SV
health for SV 25 through 32)
24 bytes