Proposed Airport Pseudolite Signal Specification for GPS Precision Approach Local Area Augmentation Systems

Abstract

The availability and continuity of accuracy and integrity are major concerns for GPS-based precision approach and landing systems without augmentation. Thus, following the lead of the FAA baseline Local Area Augmentation System (LAAS) architecture that includes pseudolites, RTCA Special Committee 159 Working Group 4a for GPS/Precision Landing Guidance has set up an Airport Pseudolite (APL) subgroup. The purpose of this subgroup is to develop LAAS pseudolite standards. This subgroup is responsible for trade studies necessary for the development of an APL signal structure. This development is well underway, starting with a set of basic assumptions to be considered in that development. Minimum performance criteria for a viable pseudolite signal structure are also being established. This paper presents these basic assumptions to be considered and the resulting minimum performance criteria for the APL signal structure. Then, the details of the proposed APL signal specification currently under review that meets those criteria are described. Also, the analytical results that justify the proposal against the defined considerations and minimum performance requirements are presented.