GBAS Standards

Fundamentals
Title	GBAS Standards
Edited by	GMV
Level	Intermediate
Year of Publication	2011

As defined by the International Civil Aviation Organization (ICAO), a Global Navigation Satellite System (GNSS) is a worldwide position and time determination system that includes one or more satellite constellations, aircraft receivers, and system integrity monitoring, augmented as necessary to support the required navigation performance for the intended operation. Current satellite navigation systems (e.g. GPS, GLONASS or Galileo) were not designed to meet the real-time integrity monitoring capability required by the civil aviation navigation safety needs. To overcome this limitation, several Augmentation Systems have been put in place. Among these systems, the Ground Based Augmentation System (GBAS) is intended primarily to support precision approach operations.

To obtain the required precision in procedures and systems in each Augmentation Systems, universally accepted standards have been introduced.

Introduction

There are standards and specification applicable to GBAS message as well as the airborne GBAS receiver equipment. The specification of GBAS message data format is contained in the ICAO SARPS Appendix B for the aspects related with the signal in space, and in the RTCA MOPS DO-253, the minimum operational performance requirements applicable to the airborne GBAS receiver equipment are described.

There are 3 sets of International Standards which GBAS’s shall be compliant in order to be used by Civil Aviation Authorities:

• The Standards and Recommended Practices (SARPS) Standard for GBAS systems established and controlled by the International Civil Aviation Organization (ICAO) and which provides standards regarding the type and content of data which must be generated and transmitted by a GBAS system. In general, the GBAS provider shall broadcast a GBAS Signal in Space (SIS) compliant to this standard in terms of radio-frequency characteristics, and data content and format.
• The Minimum Operational Performance Standard (MOPS) DO-253 established and controlled by the US Radio Technical Commission for Aeronautics (RTCA) and which provides standards for an airborne GBAS receiver equipment.
• The Minimum Operational Performance Specification (MOPS) for a Ground Based Augmentation System (GBAS) ground facility to support CAT I approach and landing (incl Amd 1) ED-114, established by EUROCAE Working Group 28.

For the aeronautical user international community, the documents listed in the following table constitute the current version of the core set of documents to be used for the development of a new system devoted to provide services to these users or for the development of aeronautical user terminals.

Document Item	Reference	Issue	Date	Standardisation Body
SBAS Elements
SARPS Volume 1 – Annex 10	Including Amendments 1-92	7	July 2018	ICAO
MOPS for GPS/GBAS airborne equipment	MOPS DO-253	D	July 2017	RTCA SC 159
GNSS-Based Precision Approach Local Area Augmentation System (LAAS) Signal-In-Space Interface Control Document (ICD)	MOPS-DO-246	E	July 2017	RTCA SC 159
Minimum Aviation System Performance Standards (MASPS) for the Local Area Augmentation System (LAAS)	MASPS-DO-245	A	December 2004	RTCA SC 159
MOPS for a Ground Based Augmentation System (GBAS) ground facility to support CAT I approach and landing	ED-114	B	September 2019	EUROCAE WG28
MASPS for a Global Navigation Satellite System Ground Based Augmentation System to Support Cat 1 Operations	ED-95	1	October 1999	EUROCAE WG28
Primary Constellations
GPS
GPS L1, L2C	IS-GPS-200	L	August 2020	GPS Wing
GPS L5	IS-GPS-705	G	August 2020	GPS Wing
GPS L1C	IS-GPS-800	G	August 2020	GPS Wing
GLONASS
GLONASS L1, L2 ICD	GLONASS ICD	5.1	2008	Russian Institute of Space Device Engineering
GLONASS CDMA (L1, L2, L3)	GLONASS ICD	1.0	2016	Russian Institute of Space Device Engineering
Galileo
Galileo Open Service SIS ICD	OS SIS ICD	2.0	January 2021	European Union
Interim MOPS for airborne GALILEO receiving equipment	ED-131	Draft 1.2	July 2018	EUROCAE WG62

Standardization Bodies

Most of the information included in the same section of article SBAS Standards is applicable here. Instead of the Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment (MOPS-DO-229), for GBAS the standard is the one in MOPS Minimum Operational Performance Standards for the local area augmentation system airborne equipment (MOPS-DO-253) and MOPS for a Ground Based Augmentation System (GBAS) ground facility to support CAT I approach and landing (ED-114). Also, for the analogue of the SBAS Interoperability Working Group (IWG), there is the International GBAS Working Group, whose webpage is www.flygls.net.

Credits

The information therein was mainly obtained from the following homepages:

• ICAO website.
• EUROCAE website.
• RTCA website.