Trimble Outdoors SK8 - Manual (Page 111)

Lassen-SK8 Embedded GPS Module A-47
Trimble Standard Interface Protocol
A.17.41 Report Packet 0x5C
This packet provides tracking status data for a specified satellite. Some of the information
is very implementation-dependent and is provided mainly for diagnostic purposes. The
receiver sends this packet in response to Packet
0x 3C. The data format is shown in Table
A-49.
Table A-49. Report Packet 0x5C Data Formats
Byte/Item Type/Units Value/Meaning
Byte 0 - Satellite PRN
number BYTE/number
1 - 32
Byte 1 - Channel code BYTE Bit 4-6, channel number, 0-7
Bit position within byte 1 7(MSB) 3
(channel number beginning with 0)
Byte 2/Acquisition flag BYTE Byte 2 value:
0 never acquired
1 acquired
2 re-opened search
Byte 3/Ephemeris flag BYTE Byte 3 value:
0 flag not set
good ephemeris for this satellite
(<4 hours old, good health)
Byte 4 - 7/Signal level SINGLE same as in Packet 0x47
Byte 8 - 11/GPS time of
last measurement SINGLE/seconds Byte 8 - 11 value:
<0 no measurements have been taken
Byte 12 - 15/Elevation SINGLE/radians Approximate elevation of this satellite
above the horizon. Updated about
every 15 seconds. Used for searching
and computing measurement
correction factors.
Byte 16 - 19/Azimuth SINGLE/radians Approximate azimuth from true north
to this satellite. Updated typically about
every 3 to 5 minutes. Used for
computing measurement correction
factors.
Byte 20/old
measurement flag BYTE Byte 20 value:
0 flag not set
>0 the last measurement is too old to
use for a fix computation.
Byte 21/Integer msec
flag BYTE Byte 21 value:
Don't have good knowledge of integer
millisecond range to this satellite
1 msec from sub-frame data collection
2 verified by a bit crossing time
3 verified by a successful position fix
4 suspected msec error