Navigation using High-Frequency Ground Beacons and Ionosphere Model Corrections

Yoav Baumgarten and Mark L. Psiaki

Abstract:	A new navigation concept is developed that relies on passive one-way ranging using pseudorange measurements of High-Frequency (HF) beacon signals that are reflected off of the ionosphere. This concept is being developed as a possible alternative to GNSS positioning and timing services, with clear benefits where it comes to costs and system redundancy. The proposed system’s HF signals are transmitted from ground-based beacons. They travel from the known beacon locations to the unknown user equipment (UE) location along ray paths that reflect off of the Earth and the ionosphere. This reliance on reflected signals allows the beacons to lie beyond the receiver’s horizon. If a set of beacon signals reaches the UE receiver with sufficient geometric diversity, then the three-dimensional position and the clock offset of the receiver can be determined. Ionospheric modeling uncertainty can cause large errors in the deduced UE position and clock offset. This can be compensated by developing a parametric model of ionosphere variability and by estimating corrections to these parameters as an integral part of the navigation solution. A batch filter is developed to estimate the UE position, clock offset, and corrections to an a priori ionosphere model. This paper presents and initial evaluation of this concept. It analyzes the observability and possible accuracy of this system. For a case study involving significant errors in the a priori ionospheric parameters, the total error in position estimate was in an order of hundreds of meters in the horizontal plane and a couple of meters in the vertical direction. The a posteriori estimates for the ionosphere exhibits significantly smaller errors compared to the a priori data.
Published in:	Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2015) September 14 - 18, 2015 Tampa Convention Center Tampa, Florida
Pages:	1425 - 1435
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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