EUROCAE ED-95 PDF

PURPOSE AND SCOPE

This document contains Minimum Aviation System Performance Specification (MASPS) for a Ground Based Augmentation System (GBAS), as part of the Global Navigation Satellite System (GNSS), to support Cat I precision approaches and landing, with a growth capability to support Cat II / III operations.

The purpose of this MASPS is to define the system performance requirements and also to allocate the system performance requirements to the Minimum Operational Performance Specifications (MOPS) of the two major sub-systems.

To ease the introduction of GBAS, the operational concept uses pilot and auto-pilot interfaces, already approved for ILS operation, thereby minimising the impact at the cockpit level. Furthermore, ATC procedures for GBAS will be as close as possible to those of ILS.

Primary performance parameters are accuracy, integrity, availability, and continuity. These parameters are specified at system level and then allocated to the major subsystems.

Functional specifications are used where possible so that implementers may have flexibility in developing the GBAS equipment.

Chapter 2 of this document provides system information and assumptions needed to understand the rationale for equipment characteristics and requirements stated in the remaining sections. It describes typical equipment applications and operational goals and forms the basis of the specifications in Chapter 3.

Chapter 3 contains the minimum system performance specifications for the complete system and for each sub-system that is a required element of the system. These standards specify the required performance under the standard environmental conditions.

Appendices A to H specify the broadcast message formats, the allocations of accuracy, continuity and integrity, the integrity alert system latency, the VHF and the C-Band implementations of the broadcast system and interference environment.

Appendices A and F to H refer to the signal transmitted by the ground station and are normative. These appendices are consistent with the draft SARPS approved by GNSSP3 and may be superseded by future versions of ICAO documents :

• Appendix A specifies the broadcast message format.

• Appendices F and G describe the VHF and C Band implementations of the broadcast system.

• Appendix H describes the interference environment.

When the GBAS signal in space is specified by ICAO SARPS, these appendices will be superseded by the relevant ICAO documents.

Appendices B through E are informative and contain rationale for the requirements and allocations given in Section 3 on, respectively, accuracy, continuity, integrity and the integrity alert system latency and availability.