Gps data, 1. nmea $gpgga string definition – Campbell Scientific GPS16-HVS Garmin GPS Receiver User Manual

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Garmin 16-HVS GPS Receiver

3. GPS Data

The Garmin16-HVS has several data formats available. The Garmin16-HVS is

configured to output the NMEA $GPGGA time and position string. It is

possible to configure the Garmin16-HVS to output other NMEA strings

including the $GPVTG track made good and ground speed string. See

Appendix D for details.

Sample NMEA $GPGGA data string:

$GPGGA,hhmmss,llll.lll,a,nnnnn.nnn,b,t,uu,v.v,w.w,M,x.x,M,y.y,zzzz*hh<CR><LF>

TABLE 3-1. NMEA $GPGGA String Definition

Field Description
0

$GPGGA

NMEA string identifier

1

hhmmss

UTC of Position: Hours, minutes, seconds

2

1111.111

Latitude: Degrees, minutes, thousandths of minutes

3

a

N (North) or S (South)

4

nnnnn.nnn

Longitude: Degrees, minutes, thousandths of minutes

5

b

E (East) or W (West)

6

t

GPS Quality Indicator: 0 = No GPS, 1 = GPS, 2 =

DGPS

7

uu

Number of Satellites in Use

8

v.v

Horizontal Dilution of Precision (HDOP)

9

w.w

Antenna Altitude in Meters

10

M

M = Meters

11

x.x

Geoidal Separation in Meters

12

M

M = Meters. Geoidal separation is the difference

between the WGS-84 earth ellipsoid and mean-sea-

level.

13

y.y

Age of Differential GPS Data. Time in seconds since

the last Type 1 or 9 Update

14

zzzz

Differential Reference Station ID (0000 to 1023)

15

*

Asterisk, generally used as the termination character

16

hh

Checksum

17

<CR><LF> Carriage return, line feed characters.

Sample $GPGGA output strings:

Cold Start

No satellites acquired, Real Time Clock and Almanac invalid:

$GPGGA,,,,,,0,00,,,,,,,*66

Warm Start

No satellites acquired, time from Real Time Clock, almanac valid:

$GPGGA,235032.0,,,,,0,00,,,,,,,*7D

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