Selecting Among Dual Frequency Multiple Constellation (DFMC) Satellite-Based Augmentation Systems (SBAS) During En-route and Non-Precision Flight Operations

Abstract

As satellite-based augmentation systems (SBAS) begin their second decade, new satellite core constellation deployment, operation of additional SBAS, and provisioning of dual-frequency service will increase the regions of multiple overlapping SBAS service. New user equipment designs need to consider operation in such regions. Current SBAS standards do not identify required SBAS selection criteria for enroute or terminal operations. Without new SBAS selection requirements, equipment could operate in the same airspace in the enroute or terminal mode using different SBAS augmenting different core constellations. Observed SBAS selection during interoperability flight tests with single-frequency equipment shows differences in transition behavior, some of which may result in loss of user SBAS service. This paper assesses several possible SBAS selection methods for overall service availability and SBAS selection potential. The analysis shows that broadcast integrity parameter methods can automatically select the nearest SBAS with high probability and service availability.