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NMEA 0183 Protocol Sentences Explained
NMEA 0183 Protocol Sentences Explained
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Written by Sierra Wireless
Updated over 3 years ago

Here are the most common NMEA Sentences used in GPS configurations on OMG and MG90 devices and can be configured in the GPS tab on the LCI for both local and remote forwarding:

GGA - essential fix data which provide 3D location and accuracy data.

$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47

Where:

GGA Global Positioning System Fix Data

123519 Fix taken at 12:35:19 UTC

4807.038,N Latitude 48 deg 07.038' N

01131.000,E Longitude 11 deg 31.000' E

1 Fix quality: 0 = invalid

1 = GPS fix (SPS)

2 = DGPS fix

3 = PPS fix

4 = Real Time Kinematic

5 = Float RTK

6 = estimated (dead reckoning) (2.3 feature)

7 = Manual input mode

8 = Simulation mode

08 Number of satellites being tracked

0.9 Horizontal dilution of position

545.4,M Altitude, Meters, above mean sea level

46.9,M Height of geoid (mean sea level) above WGS84

ellipsoid

(empty field) time in seconds since last DGPS update

(empty field) DGPS station ID number

*47 the checksum data, always begins with *

GSA - GPS DOP and active satellites. This sentence provides details on the nature of the fix.

$GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39

Where:

GSA Satellite status

A Auto selection of 2D or 3D fix (M = manual)

3 3D fix - values include: 1 = no fix

2 = 2D fix

3 = 3D fix

04,05... PRNs of satellites used for fix (space for 12)

2.5 PDOP (dilution of precision)

1.3 Horizontal dilution of precision (HDOP)

2.1 Vertical dilution of precision (VDOP)

*39 the checksum data, always begins with *

GSV - Satellites in View shows data about the satellites that the unit might be able to find based on its viewing mask and almanac data. It also shows current ability to track this data.

$GPGSV,2,1,08,01,40,083,46,02,17,308,41,12,07,344,39,14,22,228,45*75

Where:

GSV Satellites in view

2 Number of sentences for full data

1 sentence 1 of 2

08 Number of satellites in view

01 Satellite PRN number

40 Elevation, degrees

083 Azimuth, degrees

46 SNR - higher is better

for up to 4 satellites per sentence

*75 the checksum data, always begins with *

RMC - NMEA has its own version of essential gps pvt (position, velocity, time) data. It is called RMC, The Recommended Minimum, which will look similar to:

$GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A

Where:

RMC Recommended Minimum sentence C

123519 Fix taken at 12:35:19 UTC

A Status A=active or V=Void.

4807.038,N Latitude 48 deg 07.038' N

01131.000,E Longitude 11 deg 31.000' E

022.4 Speed over the ground in knots

084.4 Track angle in degrees True

230394 Date - 23rd of March 1994

003.1,W Magnetic Variation

*6A The checksum data, always begins with *

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