D Logs summary

198 MiLLennium Command Descriptions Manual

SPHA/B Speed and Direction Over Ground
This log provides the actual speed and direction of motion of the GPSCard antenna over ground, at the time of
measurement, and is updated up to 10 times per second. It should be noted that the GPSCard does not determine
the direction a vessel, craft, or vehicle is pointed (heading), but rather the direction of motion of the GPS antenna
relative to ground.

SPHA

Structure:
Example:
$SPHA,640,333111.00,0.438,325.034,2.141,0*02[CR][LF]

SPHB

Format: Message ID = 06 Message byte count = 52
$SPHA week seconds hor spd trk gnd
vert spd sol status *xx [CR][LF]
Field # Field type Data Description Example
1$SPHA Log header $SPHA
2week GPS week number 640
3seconds GPS seconds into the week 333111.00
4hor spd Horizontal speed over ground, in metres per second 0.438
5trk gnd Actual direction of motion over ground (track over grou nd)
with respect to True North, in degrees 325.034
6vert spd Vertical speed, in metres per second, where positive
values indicate increasing altitude (up) and negative
values indicate decreasing altitude (down)
2.141
7sol status Solution status as listed in Table D-1 0
8*xx Checksum *02
9[CR][LF] Sentence terminator [CR][LF]
Field # Data Bytes Format Units Offset
1 Sync 3 char 0
(header) Checksum 1 char 3
Message ID 4 integer 4
Message byte count 4 integer 8
2Week number 4 integer weeks 12
3Seconds of week 8 double seconds 16
4Horizontal speed 8 double metres per second 24
5Track over ground (TOG) 8 double degrees 32
6Vertical speed 8 double metres per second 40
7Solution status 4 integer 48