User`s manual

AQ-300 Operating Manual
AQ Max Technology Inc. 6F-2, No.90, Sec.1, Chung-Hwa East Rd, Tainan, Taiwan
Fax: ++886 6 2380861 E-Mail: [e-mail] Web: www.aqmax.com
15
Course Over Ground and Ground Speed
Table A-10 contains the values for the following example:
$GPVTG,309.62,T, ,M,0.13,N,0.2,K*6E
Table A-10 VTG Data Format
Name Example Units Description
Message ID $GPVTG VTG protocol header
Course 309.62 Degrees Measured heading
Reference T True
Course Degrees Measured heading
Reference M Magnetic (1)
Speed 0.13 Knots Measured horizontal speed
Units N Knots
Speed 0.2 Km/hr Measured horizontal speed
Units K Kilometers per hour
Checksum *6E
<CR> <LF> End of message termination
(1) SiRF Technology Inc. does not support magnetic declination. All “course over
ground” data are geodetic WGS84 directions.
RTCM Received
Data
The default communication parameters for DGPS Input are 9600 baud, 8
data bits, stop bit, and no parity. Position accuracy of less than 5 meters
can be achieved with the AQ-300 by using Differential GPS (DGPS)
real-time pseudo-range correction data in RTCM SC-104 format, with
message types 1, 5, or 9. As using DGPS receiver with different
communication parameters, AQ-300 may decode the data correctly to
generate accurate messages and save them in battery-back SRAM for
later computing.