Global Navigation Satellite System (GNSS)
Data Formats
Dinesh ManandharCenter for Spatial Information Science
The University of Tokyo
Contact Information: dinesh@iis.u-Tokyo.ac.jp

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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Data Formats: NMEA, RINEX

References: https://www.nmea.org/
http://freenmea.net/docs
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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National Marine Electronics Association (NMEA) Format• NMEA is format to output measurement data from a sensor in a
pre-defined format in ASCII• In the case of GPS, It output GPS position, velocity, time andsatellite related data
• NMEA sentences (output) begins with a “Talker ID” and“Message Description”• Example: $GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47• “$GP” is Talker ID• “GGA” is Message Description to indicate for Position Data
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

Slide : 3

NMEA Data Format
GGA - 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
123519Fix 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 level46.9,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 *Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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Serial Configuration of NMEA
• Baud rate
• Parity• Data bits
• Stop bits
• Handshake: 4800: None:8:1: NoneDinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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RINEX Data Format• Receiver Independent Exchange Format (RINEX) is a data exchange format forraw satellite data among different types of receivers.

• Different types of receivers may output position and raw data in proprietary formats• For post-processing of data using DGPS or RTK it is necessary to use data fromdifferent types of receivers. A common data format is necessary for this purpose.
• Example: How to post process data from Trimble, Novatel and Septenrtio receivers tocompute a position?

• RINEX only provides Raw Data. It does not provide position output.
• User has to post-process RINEX data to compute position• Raw data consists of Pseudorage, Carrierphase, Doppler, SNR• RINEX basically consists of two data types• “*.*N” file for Satellite and Ephemeris Related data.
• Also called Navigation Data

• “*.*O” file for Signal Observation Data like Pseudorange, Carrier Phase, Doppler, SNR• Also called Observation Data

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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RINEX “N” File for GPS

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

Slide : 7RINEX “N” File for QZSS

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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RINEX “N” File for GLONASS

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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RINEX “N” File for GALILEO

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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RINEX “N” File for BEIDOU

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

Slide : 11

RINEX “N” File for SBAS

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jpSlide : 12

RINEX “O” File GPS, GLONASS, GALILEO, QZSS, SBAS

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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RINEX “O” File, Continued from previous slide

Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@iis.u-tokyo.ac.jp

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