Trimble Outdoors THUNDERBOLT 64057-00-ENG - Manual (Page 53)

Trimble ThunderBolt E GPS Disciplined Clock User Guide 51
Trimble Standard Interface Protocol A
Report Packet 0x49: Almanac Health
This packet provides health data on 32 satellites. Packet data consists of a data byte for
each of 32 satellites, each data byte containing the 6-bit health from almanac page 25.
Report Packet 0x4A: Single Precision LLA Position Fix
The packet provides current GPS position fix in LLA (latitude, longitude, and altitude)
coordinates. If the I/O position option is set to "LLA" and the I/O precision of position
output is set to single precision, then the receiver sends this packet each time a fix is
computed. The data format is shown below:
The LLA conversion is done according to the datum selected using packet 0x8E-15.
The default is WGS-84. Altitude is referred to the datum or the MSL Geoid, depending
on which I/O LLA altitude option is selected with packet 0x35. The time of fix is in GPS
time or UTC, depending on which I/O timing option is selected.
C
CAUTION – When converting from radians to degrees, significant and readily visible
errors will be introduced by use of an insufficiently precise approximation for the
constant p (pi). The value of a constant p as specified in ICD-GPS-200 is 3.1415926535898.
C
CAUTION – The MSL option is only valid with the WGS-84 datum. When using other
datums, only the HAE option is valid.
Byte Item Type
0 Health of satellite #1 bit field
1 Health of satellite #1 bit field
2 Health of satellite #1 bit field
- - -
31 Health of satellite #31 bit field
Byte Item Type Units
0-3 Latitude Single radians: + for north, - for south
4-7 Longitude Single radians: + for east, - for west
8-11 Altitude Single meters
12-15 Clock Bias Single meters
16-19 Time-of-fix Single seconds