SXBlue GPS Reference Manual
27
5.2.7 RRE Data Message
The RRE message contains the satellite range residuals and estimated position error.
The table below breaks down the RRE data message into its components. This
message has the following format:
$GPRRE,n,ii,rr…ii,rr,hhh.h,vvv.v *cc<CR><LF>
Table 5-9 RRE Data Message Defined
Field
Description
n
Number of satellites used in position
computation
ii
Satellite number
rr
Range residual in meters
hhh.h
Horizontal position error estimate in meters
vvv.v
Vertical position error estimate in meters
*cc
Checksum
<CR><LF>
Carriage return and line feed
5.2.8 VTG Data Message
The VTG message contains velocity and course information. The table below breaks
down the VTG data message into its components. This message has the following
format:
$GPVTG,ttt,c,ttt,c,ggg.gg,u,ggg,gg,u*cc<CR><LF>
Table 5-10 VTG Data Message Defined
Field
Description
ttt
True course over ground, ttt = 000 to 359, in degrees
c
True course over ground indicator, c = T always
ttt
Magnetic course over ground, ttt = 000 to 359, in degrees
c
Magnetic course over ground Indicator, always c = M
ggg.gg
Speed over ground, 000 to 999 knots
u
Speed over ground units, u = N = Nautical mile/h
ggg.gg
Speed over ground, 000 to 999 km/h
u
Speed over ground units, u = K = kilometer/h
*cc
Checksum
<CR><LF>
Carriage return and line feed