EUROCAE ED-97 PDF

INTRODUCTION

This document has been prepared by EUROCAE Working Group 28 with the expectation that it would be published as a Minimum Operational Performance Specification (MOPS), however the rate of change of the technology in this area and the fact that it has not been possible to validate fully the performance parameters of GLONASS to the standard sufficient to underpin EUROCAE MOPS, the decision has been taken to publish the data as an Interim Technical Performance Statement. The title has been chosen to indicate that prior to use the data needs to be checked. Key discussions on technical performance take place within the ICAO GNSS Panel and it is output from this Panel that should be considered as the most up to date and definitive source of information against which MOPS (using the methods outlined in this document) can be derived.

This document contains the best estimate of operational performance statements for airborne EGNOS/WAAS receiver equipment intended to be used as a primary means of navigation for all phases of flight from En-route down to Non Precision Approach. The terminology EGNOS/WAAS is generically used to refer to Satellite Based Augmentation System (SBAS) providers such as the European Geostationary Navigation Overlay System (EGNOS) and the US Wide Area Augmentation System (WAAS). These Standards are intended to be applicable to other SBAS providers such as Japan's Multifunctional Transport Satellite Augmentation System (MSAS). This document specifies EGNOS/WAAS equipment using the GPS constellation. Equipment combining GPS and GLONASS may be specified in a subsequent publication.

These statements are designed to ensure that airborne EGNOS/WAAS receiving equipment can be designed to be compatible with the technical specification for GPS as defined in the document "GPS Standard Positioning Service - Signal Specifications" and for SBAS signal in space definition as defined in ICAO GNSS Standards and Recommended Practices (SARPs).

This document defines performance, functions and features for a 2D system, which provides only lateral guidance. The performance of specific equipment may be enhanced or superior to this specification depending on the intended application and configuration.

Chapter 1 provides information explaining the need for the equipment characteristics and tests defined in the remaining chapters. It describes typical equipment applications and operational objectives and is the basis for the performance criteria specified in Chapter 2 and Chapter 3. Definitions essential to proper understanding of this document are also provided in Chapter 1.

Chapter 2 contains general design specifications.

Chapter 3 contains the minimum performance specification for the equipment, defining performance under standard operating conditions.

Chapter 4 contains provisions for the minimum performance specification of a EGNOS/WAAS receiving equipment using combined GPS and GLONASS signals; however the reader should note that some of the GLONASS data has not been validated fully.

Chapter 5 prescribes the environmental test conditions which provide a laboratory means of determining the overall performance characteristics of the equipment under conditions representative of those which may be encountered in actual operations.

Chapter 6 describes recommended test procedures for demonstrating compliance with the minimum performance specifications contained in Chapter 3.

Chapter 7 specifies the performance of the installed equipment. Ground and flight tests for the installed equipment are included. The appendices contain additional information and guidance material regarding the testing and use of an EGNOS/WAAS receiving equipment.

Appendix A contains the EGNOS/WAAS Signal Specification and Appendices B and G describe the standard Interference Environment for GPS and GLONASS respectively.

Appendix C contains GPS, GLONASS, EGNOS and WAAS assumptions.

Appendix D details the algorithms which are used to compute EGNOS/WAAS provided integrity.

Appendix E provides the budget allocated for Integrity calculations.

Appendix F provides information concerning interoperability.

Appendix G provides information on GLONASS characteristics.

Appendix H provides justification for the testing and pass/fail criteria used in Chapter 6.