Data Sheet

LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi District, New Taipei City 221, Taiwan
℡ 886-2-8698-3698
 886-2-8698-3699
www.locosystech.com
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© 2006 LOCOSYS Technology Inc.
4 GPS receiver
Chip MediaTek MT3339
Frequency L1 1575.42MHz, C/A code
Channels Support 66 channels (22 Tracking, 66 Acquisition)
Update rate 1Hz default, up to 10Hz
Hot start (Open Sky) < 1s (typical)
32s (typical) without AGPS
Acquisition Time
Cold Start (Open Sky)
<15s (typical) with AGPS (hybrid ephemeris prediction)
Autonomous 3m (2D RMS)
Position Accuracy
SBAS 2.5m (depends on accuracy of correction data)
Datum WGS-84 (default)
Max. Altitude < 50,000 m
Max. Velocity < 515 m/s
Protocol Support NMEA 0183 ver 3.01
9600 bps
(1)
, 8 data bits, no parity, 1 stop bits (default)
1Hz: GGA, GLL, GSA, GSV, RMC, VTG
Note 1: Both baud rate and output message rate are configurable to be factory default.
5 Software interface
5.1 NMEA output message
Table 5.1-1 NMEA output message
NMEA record Description
GGA
Global positioning system fixed data
GLL
Geographic position - latitude/longitude
GSA
GNSS DOP and active satellites
GSV
GNSS satellites in view
RMC
Recommended minimum specific GNSS data
VTG
Course over ground and ground speed
 GGA--- Global Positioning System Fixed Data
Table 5.1-2 contains the values for the following example:
$GPGGA,053740.000,2503.6319,N,12136.0099,E,1,08,1.1,63.8,M,15.2,M,,0000*64
Table5.1- 2 GGA Data Format
Name Example Units Description
Message ID $GPGGA GGA protocol header
UTC Time 053740.000 hhmmss.sss
Latitude 2503.6319 ddmm.mmmm