Description / Abstract: Introduction

This document contains minimum operational performance standards (MOPS) for airborne navigation equipment using the Global Positioning System (GPS) augmented by the Local Area Augmentation System (LAAS). These standards are partially derived from the requirements specified in RTCA/DO-245(), Minimum Aviation System Performance Standards (MASPS) for the Local Area Augmentation System (LAAS). Additional requirements have been derived by analysis of operational intent and direct allocation of performance requirements between airborne and ground systems. Throughout this document, the term “LAAS” is used as a generic reference to ground-based augmentation systems (GBAS) as defined by the International Civil Aviation Organization (ICAO), as the requirements in this standard are intended to comply with the ICAO Standards and Recommended Practices (SARPs) for the GBAS aircraft element.

Note: This MOPS was developed in conjunction with the ICAO Annex 10 Volume I SARPs (through Amendment 91). The shorter notation “ICAO Annex 10” is used in this document to refer to the SARPs.

The standards in this document define minimum performance requirements, functions and features for LAAS airborne equipment to support multiple types of service that are intended to support precision approach operations and guided takeoff for all weather minimums. This standard also covers the computation and output of position, velocity, and time (PVT) to support area navigation and other applications.

Note: The requirements for area navigation systems continue to evolve. Applicable standards include RTCA/DO-236(), RTCA/DO-229(), RTCA/DO-187() [as amended by TSO-C115()] and RTCA/DO-316().

Compliance with these standards by manufacturers, installers and users is recommended as a means of assuring that the equipment will satisfactorily perform its intended functions under conditions encountered in routine aeronautical operations. The regulatory application of these standards is the responsibility of appropriate government agencies. The Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA) have published two Technical Standard Orders (TSO) for GPS/LAAS equipment, one for the LAAS VHF Data Broadcast (VDB) receiver function (TSO/ETSO-C162) and another for the LAAS Position And Navigation (PAN) function (TSO/ETSO-C161). These TSOs and ETSOs do not currently address GBAS Approach Service Type D (GAST D). It is expected that regulators will use this MOPS for authorizations with GAST D.

The VDB Adjacent Channel interference requirements specified in this MOPS are harmonized with the ICAO Annex 10 GBAS SARPs. The ICAO NSP Spectrum Working Group (SWG), with support from RTCA SC-159, is updating the GBAS SARPs frequency compatibility criteria that are intended to be effective in November 2020. It is intended that this MOPS remain harmonized with the ICAO Annex 10 GBAS SARPs, including changes to the avionics D/U requirements that may result from updating the GBAS SARPs frequency compatibility criteria. Refer to Section K.5.2.2 in Appendix K for further details.

The word "equipment", as used in this document, includes all components or units necessary (as determined by the equipment manufacturer or installer) to properly perform its intended function.

In this document, the term “shall” is used to indicate requirements. An approved design would comply with every requirement, which can be assured by inspection, test, analysis, or demonstration. The term “must” is used to identify items which are important but are either duplicated somewhere else in the document as a “shall”, or are considered to be outside the scope of this document. The term “should” is used to denote a recommendation that would improve the LAAS equipment, but does not constitute a minimum requirement.

This document facilitates traceability by identifying each specific requirement with a requirement designator. The notation “[LAAS-xxx]”, where xxx is a three-digit number, identifies each specific requirement for traceability purposes.

Section 1 of this document provides 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 for the standards stated in Sections 2 through 4.

Section 2 contains the equipment performance requirements and test procedures for the VDB receiver function and the PAN function. These standards define required performance under standard operating conditions and stressed physical environmental conditions.

Section 3 describes those additional requirements and tests that ensure that the LAAS equipment performs its intended function in a particular installation. Tests for the installed equipment are included when performance cannot be adequately determined through bench testing.

Section 4 describes the characteristics of installed LAAS equipment, and the expected pilot reactions to specified displays.

Appendix A contains a listing of abbreviations and definition of terms used in this document.

Appendix B lists requirements, by requirements number, that have changed from the prior version of this document. It also indicates requirements that have been added.

Appendix C contains an example of Final Approach Path and deviation calculations.

Appendix D defines the GPS interference environment for which the PAN equipment is required to operate.

Appendix E describes the approach and positioning service volumes and the maximum distance for use of differential corrections.

Appendix F is reserved.

Appendix G defines rotorcraft specific requirements for LAAS equipment. It is noted that the PinS operations defined in Appendix G are based on GAST C. This MOPS was not developed to support rotorcraft operations based on GAST D.

Appendix H discusses test considerations.

Appendix I discusses GBAS Approach Service Types, Facility Classifications, Airborne Equipment Classifications, and Approach Facility Classifications.

Appendix J gives an example of how airborne geometry screening requirements can be derived based on ground monitor requirements and airplane performance for one airplane integration.

Appendix K provides the rationale for the VDB airborne receiver sensitivity and dynamic range requirements based upon the overall VDB system link budget.

Appendix L describes how a ground station uses reference receivers and the broadcast Bvalue parameters corresponding to the H1 hypotheses to support GBAS aided inertial systems.