GNSS Data Formats
Dinesh ManandharCenter for Spatial Information Science
The University of Tokyo
Contact Information: dinesh@csis.u-tokyo.ac.jp
Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 1

Data Formats: NMEA, RINEX, RTCM

References: https://www.nmea.org/
http://freenmea.net/docs
Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 2

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 outputs 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
Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.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' N01131.000, ELongitude 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 *Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 4

RINEX Data Format• RINEX: Receiver Independent Exchange Format is a data exchange format for raw 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 from different types ofreceivers. A common data format is necessary for this purpose.
• Example: How to post process data from Trimble, Novatel and Septenrtio receivers to compute aposition?

• 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

• The latest RINEX version is 3.04, 23 NOV 2018

• Note: Not all the software and receivers are yet compatible with the latest version• Make sure which version of RINEX works the best with your software
Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 5RINEX “N” File for GPS

Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 6

RINEX “N” File for QZSS

Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 7

RINEX “N” File for GLONASS

Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 8

RINEX “N” File for GALILEO

Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 9

RINEX “N” File for BEIDOU

Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 10

RINEX “N” File for SBAS

Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 11

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

Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 12

RINEX “O” File, Continued from previous slide

Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 13

Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 14

RTCM
• RTCM : Radio Technical Commission for Maritime Services• An internationally accepted data transmission standard for base-station data transmission
to a rover defined. The standards are defined and maintained by RTCM SC-104• RTCM SC-104 (Special Committee 104)
• Defines data formats for Differential GPS and• RTK (Real-Time Kinematic Operations)• The Current Version is RTCM-3 (10403.3)• Refer https://www.rtcm.org/ for detail information and document• Documents are not free
• A normal user does not need RTCM document.
• GNSS receivers with base-station capabilities will setup necessary messages for RTK• If you are developing a system or application you may need it
Training on GNSS – Course (T151-40), Organized by: GIC/AIT, CSIS/UT and ICG, held at: GIC/AIT, Thailand from 6 – 10 JAN 2020
Dinesh Manandhar, CSIS, The University of Tokyo, dinesh@csis.u-tokyo.ac.jp

Slide : 15