GPS Receiver Board
GPS-24 / 24A Operating Manual
Rikaline
Specifications subject to change without prior notice
Rikaline
International Corp.
14F, 171, ChengGong Rd, Sanchong CityTaipei 241, Taiwan
Tel: ++886 2 8973 1899 Fax: ++886 2 8973 1896 E-Mail:
Web: www.rikaline.com.tw
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4. Software Interface
The GPS-24 / 24A interface protocol is based on the National Marine Electronics Association's NMEA 0183
ASC
Ⅱ
interface specification, which is defined in NMEA 0183, Version 3.0 and the Radio Technical
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 GPS-24 / 24A outputs data in NMEA-0183 format as defined by the National Marine Electronics
Association (NMEA), Standard.
The default communication parameters for NMEA output are 9600 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
GPZDA
Date & Time
Detailed NMEA information is in Appendix A
4.2 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 GPS-24 / 24A 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, GPS-24 / 24A may decode the data
correctly to generate accurate messages and save them in battery-back SRAM for later computing.
4.3 Earth Datums
The GPS-24 / 24A is built in earth datum with WGS84.
