scope:

PURPOSE AND SCOPE

This document contains Minimum Operational Performance Specifications (MOPS) for a Ground Based Augmentation System (GBAS) ground facility, as part of a Global Navigation Satellite System (GNSS) to support Category 1 precision approach and landing.

This minimum operational performance specification is designed to ensure that ground equipment certified against it will be compatible with the ICAO Standards and Recommended Practices.

Chapter 1 of this document provides the information required to understand 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 stated in Chapter 2 to Chapter 4. Definitions essential to proper understanding of this document are also provided in Chapter 1.

• Chapter 2 contains general design requirements including system/subsystem performance allocations, ground equipment maintainability, hardware and software design assurance, personnel safety and environmental test conditions.

• Chapter 3 contains the specific technical requirements of the ground equipment such as coverage volume, operating modes with control and status, data link characteristics and executive monitoring.

• Chapter 4 prescribes the siting of ground equipment: location, installation, multipath and interference issues.

• Chapter 5 describes recommended test procedures for demonstrating compliance with chapters 2, 3 and 4. As the measured values of equipment performance characteristics may be a function of the method of measurement, standard test conditions and methods of test are recommended in this document.

• Appendix A provides guidance on the broadcast message format and coding.

• Appendix B provides guidance on the rationale behind the VDB power density requirements given in Chapter 3.

• Appendix C provides guidance in relation to Continuity of Service and includes an example continuity risk allocation.

• Appendix D provides the Integrity risk allocation.

• Appendix E provides information on the standard interference mask.

• Appendix F provides information on the use of multiple transmit antennas to improve the coverage of the VDB.

• Appendix G provides guidance on the objectives of Signal Quality Monitoring, the use of threat models and typical monitoring concepts.

• Appendix H provides information on testing used during selection of a suitable site for the GBAS Ground subsystem.

• Appendix I provides guidance on the use of the GBAS Positioning Service.

• Appendix J provides guidance on the optional data recording function

• Appendix K provides an example of message encoding.

In this document, the use of the word "Shall" indicates a mandated criterion; i.e. compliance with the particular procedure or specification is mandatory and no alternative may be applied.

The use of the word "Should" (and phrases such as "It is recommended that...", etc.) indicate that although the procedure or criterion is regarded as the preferred option, alternative procedures, specifications or criteria may be applied, provided that the manufacturer, installer or tester can provide information or data to adequately support and justify the alternative.