Distributed Ionosphere Monitoring by Collaborating Mobile Receivers

Okuary Osechas and Jason Rife

Abstract:	This paper presents a novel method for ionosphere anomaly monitoring, based on a network of collaborative airborne dual-frequency receivers. Each receiver measures the ionospheric delay for each satellite measurements are shared across various receivers and used in the estimation of the local ionosphere gradient, which may be different for each satellite in the case of an ionosphere storm. This monitor is able to detect anomalously large ionosphere gradients of 400 mm/km with better than 10-9 accuracy, using a network of 20 aircraft; similar sensitivity to signicantly smaller gradients is possible if more aircraft are involved in the scheme. The method is tested in simulation and it is shown that the probability of misdetection is largely insensitive to radio frequency interference (RFI), even when receivers are disabled over a radius of 20 km, with collaborating aircraft uniformly spread over a radius of 50 km. From this result, precision landing (with ionosphere mitigation) is possible even when all but one ground-station reference receiver is incapacitated by RFI. Also, because the proposed algorithm detects anomalies over large baselines (tens of kilometers of separation), this algorithm could enable approach and landing at one airport using differential corrections broadcast from another airport in an urban metroplex. Such operations are not typical using standard ionosphere mitigation techniques because of tight restrictions on the allowed broadcast distance, called Dmax.
Published in:	Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012) September 17 - 21, 2012 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	2191 - 2200
Cite this article:	Osechas, Okuary, Rife, Jason, "Distributed Ionosphere Monitoring by Collaborating Mobile Receivers," Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012), Nashville, TN, September 2012, pp. 2191-2200.
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