Joint Detection and Estimation of Weak GNSS Signals with Application to Coarse Time Navigation

Zhe He and Mark Petovello

Abstract:	GNSS receivers have already widely been used in vast applications. The focus of this paper is to improve the capability in harsh environments. In a high sensitivity receiver, a conventional approach is to first detect signals on satellite-by-satellite basis, then generate measurements and estimate a position solution. To further enhance the receiver performance, researchers have proposed to non-coherently make use of all-in-view satellite information. Examples of this include ‘collective detection’ and ‘maximum likelihood positioning’. Both approaches investigated the potentials of this ‘joint’ approach either in a detection aspect by evaluating the receiver operating characteristic (ROC) or an estimation aspect based on an estimator’s Cramer-Rao lower bound. The term ‘joint’ is used in this paper because this approach automatically combines detection (of all available satellites) and estimation (navigation solution) process together. In this paper, maximum a posteriori (MAP) detection and estimation analysis of conventional block processing, receiver and ‘joint’ approach receiver has been conducted, and comparisons have been worked out. Metrics such as a posteriori likelihood ratio/detection rate is derived, which depend on both the estimation and detection metrics. In the end, a joint approach coarse-time high sensitivity software receiver with long non-coherent integration has been implemented and demonstrated. Real data from indoor environment shows promising improvements over conventional coarse-time block processing receiver.
Published in:	Proceedings of the 27th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2014) September 8 - 12, 2014 Tampa Convention Center Tampa, Florida
Pages:	1554 - 1567
Cite this article:	He, Zhe, Petovello, Mark, "Joint Detection and Estimation of Weak GNSS Signals with Application to Coarse Time Navigation," Proceedings of the 27th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2014), Tampa, Florida, September 2014, pp. 1554-1567.
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