Adaptive Hybrid Positioning Engine

Mohamed Youssef and Ashkan Izadpanah

Abstract:	New Location-Based Services require instantaneous reliable positioning systems that can work everywhere. Since no single positioning technology can meet such requirements, companies have been combining different positioning technologies in an effort to mitigate and compensate for each technology´s own limitations. Such combinations typically include GNSS (Global Navigation Satellite System) as the primary solution, along with one or more non-GNSS positioning systems such as Wi-Fi, cellular and/or inertial navigation sensors. When multiple positioning technologies co-exist in a handset, they are generally referred to as a Hybrid Positioning Engine (HPE)[1],[2],[3]. Current HPE however can best be described as discrete collections of positioning options, each working in an independent manner, and from which the best solution is selected [1], [3]. This paper introduces a novel and patent-pending adaptive HPE technique developed by Rx Networks. In adaptive HPE technique, Assisted-GNSS (A-GNSS) and non-GNSS positioning technologies actively collaborate to aid the GNSS receiver to work out a position when it otherwise cannot do so on its own. The technique presumes the device is already taking advantage of any available GNSS assistance options and that if no satellite signals are visible, the traditional fallback on non-GNSS coarse position will take place. However, whenever less than the minimum number of required satellites are detected by the GNSS receiver, this adaptive HPE technique can be invoked to increase the probability of an accurate solution. The adaptive HPE works in one of two possible modes: 1) the basic mode (Loosely-Coupled HPE) combines a Cell-ID supplied by the non-GNSS positioning system with whatever few satellites the GNSS receiver was able to acquire to yield a solution of higher accuracy than the Cell-ID of the non-GNSS positioning system; 2) the advanced mode (Tightly-Coupled HPE) uses the Cell-ID supplied by the non-GNSS positioning system to help the GNSS receiver acquire additional satellites beyond those it acquired on its own. If enough satellites can be added with the Tightly-Coupled mode, the GNSS receiver can resolve its location conventionally. Otherwise, the solution falls back to the Loosely-Couple mode described above.
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:	3937 - 3944
Cite this article:	Youssef, Mohamed, Izadpanah, Ashkan, "Adaptive Hybrid Positioning Engine," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 3937-3944.
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