Transcript GPS Data Format NEMA-0183

RTCM Data Format
(Radio Technical Commission
for Maritime Services)
Overview of Common GPS Data Format

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
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
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
(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 Types
RTCM
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
16
GPS Special Message
17
GPS Ephemerides
18-21 messages
18
RTK Uncorrected Carrier Phases
added in RTCM2.1
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
31-36 messages
32
Differential GLONASS Reference Station
added in RTCM2.2
33
GLONASS Constellation Health
34
GLONASS Partial Differential Correction Set
GLONASS Null Name (N<=1)
23-24 messages
added in RTCM2.3
RTCM Message Types
31-36 messages
35
GLONASS Radiobeacon Almanac
added in RTCM2.2
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 version 3.0

RTCM 3.0
 New data structure developed for network RTK
applications.

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
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
1009
Stationary RTK Reference Station ARP
1010
Stationary RTK Reference ARP with Antenna
Height
1011
Antenna Descriptor
1012
Antenna Descriptor & Serial Number
1013
System Parameters
Station Coordinates
Antenna Description
Auxiliary Operation
Information
References

RTCM Recommended Standards for Differential
NAVSTAR GPS service
www.navcen.uscg.gov/pubs/dgps/rctm104/Default.htm

RTCM Official Website
http://www.rtcm.org/

DGPS Data Formats 2.0
www.geopp.de/download/DGPS-data-formats2.pdf

Reference Station Network Information Distribution
http://www.network-rtk.info/euler/euler.html
The End
Thank you!