RTCM Data Format

(Radio Technical Commission

for Maritime Services)

RINEX Raw GPS static data format for data processing and archive

NMEA Standard related to data communication between marine

electronic devices. Transmission of GPS position from GPS receiver to other

devices (e.g. GPS receiver to PDA) For real time positioning

RTCM SC-104 Transmission of GPS correction from GPS reference station

to GPS Rover For DGPS/RTK surveys

Overview of Common GPS Data Format

Outline

Example of using RTCM Data Format

About RTCM

RTCM Data Structure

RTCM Message Types

RTCM using in SatRef

SatRef System DGPS Single-RTK Network-RTK

All GPS corrections from SatRef are in RTCM-2.1 data format.

About RTCM About RTCM

Radio Technical Commission for Maritime Services

Various Special Committees set the standards for International maritime radionavigation and radiocommunication

Examples:

1. GPS Applications

2. Electronic Charts…..

What is RTCM SC-104 ?

RTCM Special Committee (SC) 104 is the one concerned GPS correction signal. RTCM data format related to GPS corrections is called

RTCM SC-104 data format.

Compact binary data good for real-time processing

What is RTCM SC-104 ?

Different versions

RTCM-2.0 (Code correction ->DGPS)

RTCM-2.1 (Code + Phase correction -> RTK)

RTCM 2.2 ( …+ GLONASS )

RTCM 2.3 ( ….+ GPS Antenna Definition)

RTCM 3.0 (….+ Network RTK & GNSS)

RTCM Data Structure RTCM Data Structure (Versions 2.0-2.3)(Versions 2.0-2.3)

RTCM Data Structure

Each data record contains several message types for various contents. Message 1, Message2…. Message N

Each message comprises header and body Header: message type, time, length of message, Body: data for every data type

RTCM Message Types(Versions 2.0-2.3)

RTCM Message TypesRTCM Message Type

Description

1 Differential GPS Corrections

2 Delta Differential GPS Corrections

3 GPS Reference Station Parameters

4 Reference Station Datum

5 GPS Constellation Health

6 GPS Null Name

7 DGPS Beacon Almanac

8 Pseudolite Almanac

9 GPS Partial Correction Set

10 P-Code Differential Correction

11 C/A Code, L1, L2 Delta Corrections

12 Pseudolite Station Parameter

13 Ground Transmitter Parameter

14 GPS Time of Week

15 Ionospheric Delay Message

RTCM Message Types

18-21 messages

added in RTCM2.1

23-24 messages

added in RTCM2.3

31-36 messages

added in RTCM2.2

16 GPS Special Message

17 GPS Ephemerides

18 RTK Uncorrected Carrier Phases

19 RTK Uncorrected Pseudorange

20 RTK Carrier Phase Corrections

21 RTK Pseudorange Corrections

22 Extended Reference Station Parameters

23 Antenna Type Defination

24 Reference Station: Antenna Reference Point (ARP) Parameter

25, 26 Undefined

27 Extended DGPS Radiobeacon Almanac

28…30 Undefined

31 Differential GLONASS Corrections

32 Differential GLONASS Reference Station

33 GLONASS Constellation Health

34 GLONASS Partial Differential Correction Set

GLONASS Null Name (N<=1)

RTCM Message Types

31-36 messages

added in RTCM2.2

35 GLONASS Radiobeacon Almanac

36 GLONASS Special Message

37 GNSS System Time Offset

38..58 Undefined

59 Proprietary Message

60..63 Multipurpose Usage

RTCM Raw Data

Binary data

RTCM Message Type 1

1. Pseudorange Corr.

2. Range Rate Corr.

RTCM Message Type 3+22

RTCM Message Type 20

RTCM Message Type 21

RTCM version 3.0

RTCM 3.0 New data structure developed for network RTK ap

plications. new signals L2C and L5 GNSS system data

• Compact Data Structure • RTCM 2.0 – 0.5 kbit / sec. (DGPS)• RTCM 2.1-2.3 requires 5 kbit / sec (DGPS+RTK)• RTCM 3.0.requires 2 kbit / sec

RTCM version 3.0

Four Groups of RTCM 3.0 GNSS RTK messages (RTCM 2004)

Group Name Message Type

Message Description

Observations 1001 L1-only GPS RTK Observables

1002 Extended L1-Only GPS RTK Observables

1003 L1 & L2 GPS RTK Observables

1004 Extended L1 & L2 GPS RTK Observables

1005 L1 Only GLONASS RTK Observables

1006 ExtendedL1-Only GLONASS RTK Observables

1007 L1 & L2 GLONASS RTK Observables

1008 Extended L1 & L2 GPS RTK Observables

Station Coordinates 1009 Stationary RTK Reference Station ARP

1010 Stationary RTK Reference ARP with Antenna Height

Antenna Description 1011 Antenna Descriptor

1012 Antenna Descriptor & Serial Number

Auxiliary Operation Information

1013 System Parameters

References RTCM Recommended Standards for Differential NAV

STAR GPS service www.navcen.uscg.gov/pubs/dgps/rctm104/Default.htm

RTCM Official Website http://www.rtcm.org/

DGPS Data Formats 2.0www.geopp.de/download/DGPS-data-formats2.pdf

Reference Station Network Information Distribution http://www.network-rtk.info/euler/euler.html

The EndThank you!