Flight Test Criteria for Qualification of GPS-Based Positioning and Landing Systems

摘要

This paper describes a methodology for determining specific test criteria for accuracy testing of Differential GNSS (DGNSS)landing systems and related TSPI systems.The intent of this paper is to remain generic so as to be applicable to multiple applications,such as Ground-Based Augmentation System(GBAS)and civil Time-Space Position Indication (TSPI)systems,as well as their military counterparts.The methodology’s test criteria are intended to account for errors in the“truth system”that are significant for some of the test parameters under some test conditions.Key criteria addressed include:what is the number of flight test maneuvers needed to provide sufficient confidence,how to account for less than “perfect”truth reference systems,and how to account for GNSS-specific issues(e.g.,satellite geometry variations).The approach advocates the use of a hierarchy of sub-system and system-level verification steps to reduce the duration and complexity of the flight test evaluations.An example is presented where simulation-based testing and sub-system testing are explicitly accounted for in the flight test confidence criteria.The result demonstrates the value in accounting for lower-level testing to obtain higher confidence in the verification of accuracy requirements.