Using Indoor Maps to Enhance Real-time Unconstrained Portable Navigation

Tao Li and Jacques Georgy

Abstract:	Indoor navigation with portable devices such as smart phones, tablets, and smart watches has been the research and development focus recently. Pedestrian Dead Reckoning (PDR) has emerged as one of most popular techniques for indoor portable navigation. Although existing works of PDR demonstrate promising results in the indoor environments regardless of how a user holds the portable device or what motion a user performs, the standalone PDR still lacks robustness because of the accumulated heading error. This shortcoming will cause a skewed path over time and produce position estimates that might not be consistent with the building layout. The resulting paths cross through walls, doors or other obstacles. Although magnetometers can provide attitude correction to PDR, they are vulnerable to interferences which are very common in the indoor environments. Therefore, map information can be used to aid the PDR solution (map matching) to provide a more reliable navigation solution. This paper presents a novel map matching method using indoor maps to enhance the accuracy and reliability of the indoor portable navigation applications. Unlike several existing map matching algorithms, the proposed indoor map matching algorithm does not rely on the assumption that a user must be constrained to a network of linked points, lines or curves. Both the geometric (shapes of the room, corridor and etc.), topological information (the relationship between objects in a building) and probabilistic information are used in the proposed map matching algorithm. Both the particle and the multi-hypothesis based filtering methods are implemented and their performances in the indoor map matching scenarios are compared in the work. Furthermore, the proposed map matching algorithm uses motion context information from the sensor-based solution to provide 2-dimentional (2D) position and heading correction to the PDR solution. The motion context may include going up/down stairs, standing/walking on escalators, elevators or conveyor and etc. In addition, the map matching algorithm can also handle the floor change automatically. Finally, field test results are presented to demonstrate the performance of the portable indoor positioning system with map matching enhancement. The tests are performed in a large shopping mall with multiple floors so that all kinds of indoor navigation scenarios are covered.
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:	3174 - 3183
Cite this article:	Li, Tao, Georgy, Jacques, "Using Indoor Maps to Enhance Real-time Unconstrained Portable 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. 3174-3183.
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