A Systems Approach to Sizing of Co-operative High-Accuracy Location (C-HALO) Services Validated by Experiments in San Francisco

Venkatesan. N. Ekambaram, Christian Manasseh, Adam Goodliss, Raja Sengupta, Kannan Ramchandran

Abstract:	This paper presents a methodology for assessing the accuracy gap between the current level-of-service provided by the US GPS constellation and DGPS, and the level-of-service envisaged by new Cooperative High-Accuracy LOcation (C-HALO) services that achieve decimeter accuracy. We present a novel GIS-based Hidden-Markov Model (HMM) predictive framework to estimate the fraction of roads with low satellite visibility counts that we call as the “dark area”, where C-HALO cannot be realized. Out of the total area of San Francisco (121 sq.km), 0.3 to 4% of the San Francisco streets are predicted to fall in the “dark” area with 95% confidence. Today, the DoD provides guarantees of 7m accuracies 97% of the time using the GPS constellation. Our dark area falls within this 3%. If it were covered by systematic new C-HALO investment, the nation might realize a similar performance guarantee at the decimeter level that would be meaningful for safe and efficient travel on the national roadway system.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	2233 - 2239
Cite this article:	Ekambaram, Venkatesan. N., Manasseh, Christian, Goodliss, Adam, Sengupta, Raja, Ramchandran, Kannan, "A Systems Approach to Sizing of Co-operative High-Accuracy Location (C-HALO) Services Validated by Experiments in San Francisco," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 2233-2239.
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