Rikaline, Appendix a software interface, A.1 nmea transmitted messages – Rikaline GPS-300 User Manual

Page 11

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GPS-300 Operating Manual

Rikaline

Rikaline

International Corp.

10F, 64, Kang-Ding Road, Taipei 108, Taiwan

Tel: ++886 2 2370 4688 Fax: ++886 2 2370 4686 E-Mail:

[email protected]

Web: www.rikaline.com.tw

11

Appendix A Software Interface

The GPS-300 interface protocol is based on the National Marine Electronics Association's NMEA 0183

ASC

Ⅱ 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).

A.1 NMEA Transmitted Messages


The GPS-300 supported by SiRF Technology Inc. also outputs data in NMEA-0183 format as defined by

the National Marine Electronics Association (NMEA), Standard.

The default communication parameters for NMEA output are 4800 baud, 8 data bits, stop bit, and no parity.

Table A-1 NMEA-0183 Output Messages

NMEA Sentence

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

A.1.1 Global Positioning System Fix Data (GGA)


Table A-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 A-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

9.0

Meters

Units M

Meters

Geoid Separation

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

Table A-3 Position Fix Indicator

Value Description

0

0 Fix not available or invalid

1

GPS SPS Mode, fix valid

2

Differential GPS, SPS Mode, fix valid

3

GPS PPS Mode, fix valid


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