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Serial Port Output
89
Serial Port Output
SNAV Message
The SNAV message contains satellite ephemeris data, including values for orbital
parameters, satellite health status, clock corrections, etc. SNAV is output in binary
format only. One message is output for each satellite being tracked. Table 4.9
below outlines the contents of the SNAV message.
The structure of the SNAV message is shown below:
$PASHR,SNV,<Ephemeris Data + Checksum>
m6
Longitude in degrees and decimal minutes
(dddmm.mmmmmm) Positive east.
±180
f7
Altitude (meters)
±99999.999
f8
Velocity in ECEF-X (m/sec).
±999.99
f9
Velocity in ECEF-Y (m/sec).
±999.99
f10
Velocity in ECEF-Z (m/sec).
±999.99
d11
Number of satellites used for position computation.
3 -12
s12
Site name
4 character
string
d13
PDOP
0 - 99
d14
HDOP
0 - 99
d15
VDOP
0 - 99
d16
TDOP
0 - 99
Table 4.9.
$PASHR,SNV Message Structure
Binary Type
Size
Contents
short
2
Wn. GPS week number
long
4
Seconds of GPS week
float
4
Tgd. Group delay (sec)
long
4
IODC. Clock data issue
long
4
toc. second
float
4
af2. sec/sec2 (clock correction)
float
4
af1. sec/sec (clock correction)
Table 4.8.
$PASHR,PBN Message Structure (ASCII) (continued)
Parameter
Description
Range