If you wish to contribute or participate in the discussions about articles you are invited to contact the Editor

DGNSS Standards: Difference between revisions

From Navipedia
Jump to navigation Jump to search
Line 48: Line 48:
|}
|}


The RTCM 10402.3 standards defined the messages for differential correction information. There are 64 types of messages. The message format is a sequence of 30 bits. The messages 1 to 17 are available in older RTCM versions, while messages 18-21 have been added in version 3 to made the standard applicable to [[Work in Progress:Real Time Kinematics|RTK]] corrections.


--------
The GNSS message types are summarized in the following table:


Hay 64 tipos de mensajes disponibles. El formato de los mensajes consiste en secuencias de palabras de 30 bits. Los últimos 6 bits en cada palabra son los bits de paridad. Cada mensaje comienza con dos palabras cabecera. La primera palabra es fija y contiene lo que se denomina preámbulo (preamble), el tipo de mensaje, y el identificador de la estación de referencia. La segunda palabra contiene la marca de tiempo en forma de cuenta Z, el número de secuencia, la longitud de mensaje y la salud de la estación de referencia.
{| class="wikitable" align="center"
 
!Message type identifier
Los mensajes 1-17 están disponibles en ambas versiones de RTCM, mientras que los mensajes 18-21 contienen cabeceras de 3 palabras y tienen como propósito el posicionamiento RTK (Real Time Kinematic) de aplicación en receptores que admitan esta técnica. La "estación base" debe de estar a una distancia de unas pocas decenas de kilómetros (20-30 Km) para que la correción sea efectiva. Esta técnica permite alcanzar precisiones centimétricas en tiempo real.
!Message Name
 
|-align="center"
Número de mensaje Estado actual Título
|0
1 Fixed Differential GPS Corrections  
| Spare
2 Fixed Delta Differential GPS Corrections 
|-align="center"
3 Fixed Reference Station Parameters 
|1  
4 Retired Surveying
| Pseudo-range Corrections
5 Fixed Constellation Health
|-align="center"
6 Fixed Null Frame
|2  
7 Fixed Beacon Almanacs
| GBAS Related Data
8 Tentative Pseudolite Almanacs
|-align="center"
9 Fixed Partial Satellite Set Differencial Corrections 
|3
10 Reserved P-Code Differential Corrections (all)  
| Reserved for ground–based ranging source
11 Reserved C/A-Code L1, L2 Delta Corrections 
|-align="center"
12 Reserved Pseudolite Station Parameters
|4
13 Tentative Ground Transmitter Parameters
| Final Approach Segment (FAS) data
14 Reserved Surveying Auxiliary Message
|-align="center"
15 Reserved Ionosphere (Troposphere) Message
|5
16 Fixed Special Message
| Predicted ranging source availability
17 Tentative Ephemeris Almanac
|-align="center"
18 Tentative Uncorrected Carrier Phase Measurements
|6
19 Tentative Uncorrected Pseudorange Measurements
| Reserved
20 Tentative RTK Carrier Phase Corrections
|-align="center"
21 Tentative RTK Pseudorange Corrections
|7
22-58 Undefined 
| Reserved for national applications
59 Tentative Proprietary Message
|-align="center"
60-63 Reserved geMultipurpose Usa
|8
| Reserved for test applications
|-align="center"
|9-255
| Spare
|}


==Other Standards==
==Other Standards==

Revision as of 10:59, 6 June 2011


FundamentalsFundamentals
Title DGNSS Standards
Author(s) GMV
Level Medium
Year of Publication 2011
Logo GMV.png


The classical DGNSS technique technique is an enhancement to a primary GNSS system, that consists of the determination of the GNSS position for an accurately-surveyed position known as reference station.

Introduction

Unlike other GNSS Augmentation systems as SBAS or GBAS, DGNSS is not used for civil aviation, but for urban transportation and in offshore areas. Therefore, the standards applying DGNSS systems are the ones of data transmission standards defined by the Special Committee 104 on DGNSS of the Radio Technical Commission for Maritime Services (RTCM). Except for RTCM, there exist other proprietary DGPS standards, such as Trimble Compact Measurement Record (CMR).

RTCM Standards

The internationally accepted data transmission standards for DGNSS are defined by RTCM, particularly by its Special Committee SC-104. RTCM SC-104 is a standard that defines the data structure for differential correction information for a variety of differential correction applications. It was developed by the Radio Technical Commission for Maritime Services (RTCM) and has become an industry standard for communication of correction information. Note that RTCM is a binary data protocol.

The applicable documents to DGNSS systems are listed in the following table and constitute the current version of the core set of documents to be used for the development of a new DGNSS system.


Document Item Reference Issue Comments
Recommended Standards for Differential GNSS (Global Navigation Satellite Systems) Service RTCM 10402.3 2.3 This standard is used around the world for differential satellite navigation systems, both maritime and terrestrial.
Differential GNSS (Global Navigation Satellite Systems) Services RTCM 10403.0 3 A more efficient alternative to RTCM 10402.3
Standard for Networked Transport of RTCM via Internet Protocol (Ntrip) RTCM 10410.0 1 An application-level protocol that supports streaming Global Navigation Satellite System (GNSS) data over the Internet
Standard for Differential Navstar GPS Reference Stations and Integrity Monitors (RSIM) RTCM 10401.2 2 A companion to RTCM 10402.3, this standard addresses the performance requirements for the equipment which broadcasts DGNSS corrections

The RTCM 10402.3 standards defined the messages for differential correction information. There are 64 types of messages. The message format is a sequence of 30 bits. The messages 1 to 17 are available in older RTCM versions, while messages 18-21 have been added in version 3 to made the standard applicable to RTK corrections.

The GNSS message types are summarized in the following table:

Message type identifier Message Name
0 Spare
1 Pseudo-range Corrections
2 GBAS Related Data
3 Reserved for ground–based ranging source
4 Final Approach Segment (FAS) data
5 Predicted ranging source availability
6 Reserved
7 Reserved for national applications
8 Reserved for test applications
9-255 Spare

Other Standards

The Compact Measurement Record (CMR) by Trimble.

Notes


References

Retrieved from "https://gssc.esa.int/navipedia/index.php?title=DGNSS_Standards&oldid=5557"