Refinement of Broadcast Integrity Methods for Space Based Augmentation System Selection

Jed Dennis, Mark Hemstad

Abstract:	As Satellite-Based Augmentation Systems (SBAS) begin their second decade, there is increasing likelihood of multiple overlapping SBAS service due to the deployment of new systems and the provisioning of dual frequency service. The new service design will need to consider interoperability of the user equipment with different SBAS and Global Navigation Satellite Systems (GNSS). Current SBAS standards do not identify required SBAS selection criteria for en-route or terminal operations. Without any new standard SBAS selection requirements, this may result in equipment operating in the same airspace in the en-route or terminal mode using different SBAS and different GNSS. Observed SBAS selection during interoperability flight tests with single frequency SBAS shows that different user equipment displays different transition behavior. Some of the behavior might lead to loss of availability. This paper assesses the performance of two SBAS selection schemes based on broadcast integrity methods, the minimum Horizontal Protection Level (HPL) method and variations of the delta Dual Frequency Range Error (?DFRE) method. The assessment identifies an improvement in the ?DFRE method using the mean ?DFRE computation. The assessment develops the behavior in the transition region and when SBAS have different performance. The analysis shows that the mean ?DFRE broadcast integrity method has the best performance of the broadcast integrity methods at selecting the associated SBAS. Additionally, it seems robust against variations in SBAS performance. Therefore the mean ?DFRE method is a candidate for automated SBAS selection.
Published in:	Proceedings of the 2015 International Technical Meeting of The Institute of Navigation January 26 - 28, 2015 Laguna Cliffs Marriott Dana Point, California
Pages:	404 - 414
Cite this article:	Dennis, Jed, Hemstad, Mark, "Refinement of Broadcast Integrity Methods for Space Based Augmentation System Selection," Proceedings of the 2015 International Technical Meeting of The Institute of Navigation, Dana Point, California, January 2015, pp. 404-414.
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