Holux gm-83 Manual Do Utilizador
GM-83 User’s manual
8
4. Software Interface
The GM-83 interface protocol is based on the National Marine Electronics Association's NMEA 0183
ASC interface specification, which is defined in NMEA 0183, Version 2.2 and the Radio Technical
Commission for Maritime Services (RTCM Recommended Standards For Differential Navstar GPS Service,
Version 2.1, RTCM Special Committee No.104).
Commission for Maritime Services (RTCM Recommended Standards For Differential Navstar GPS Service,
Version 2.1, RTCM Special Committee No.104).
4.1 NMEA Transmitted Messages
The default communication parameters for NMEA output are 4800 baud, 8 data bits, stop bit, and no
parity.
Table 4-1 NMEA-0183 Output Messages
NMEA Record
Description
GPGGA
Global positioning system fixed data
GPGLL
Geographic position- latitude/longitude
GPGSA
GNSS DOP and active satellites
GPGSV
GNSS satellites in view
GPRMC
Recommended minimum specific GNSS data
GPVTG
Course over ground and ground speed
GPMSS
Radio-beacon Signal-to-noise ratio, signal strength, frequency, etc.
4.1.1 Global Positioning System Fix Data (GGA)
Table 4-2 contains the values for the following example:
$GPGGA,161229.487,3723.2475,N,12158.3416,W,1,07,1.0,9.0,M, , , ,0000*18
Table 4-2 GGA Data Format
Name
Example
Units
Description
Message ID
$GPGGA
GGA protocol header
UTC Time
161229.487
hhmmss.sss
Latitude
3723.2475
ddmm.mmmm
N/S Indicator
N
N=north or S=south
Longitude
12158.3416
dddmm.mmmm
E/W Indicator
W
E=east or W=west
Position Fix Indicator
1
See Table 5-3
Satellites Used
07
Range 0 to 12
HDOP
1.0
Horizontal Dilution of Precision
MSL Altitude
(1)
9.0
Meters
Units
M
Meters
Geoid Separation
(1)
Meters
Units
M
Meters
Age of Diff. Corr.
second Null fields when DGPS is not used
Diff. Ref. Station ID
0000
Checksum
*18
<CR> <LF>
End of message termination
(1). SiRF Technology Inc. does not support geoid corrections. Values are WGS84 ellipsoid heights.
Table 4-3 Position Fix Indicator