An Alternative Approach to Multipath and Near-Far Problem for Indoor Geolocation Systems

Ilir F. Progri and William R. Michalson

Abstract:	Previously we have considered the navigation characteristics of an autonomous, pseudolite based, indoor geolocation system designed to operate on a single frequency modulated on “orthogonal” or “nearly orthogonal” codes to achieve channel separation. Although this system has the potential to provide accurate positioning under normal conditions; i.e., when low or no multipath is present and when the distance from the receiver is almost equally spaced from the pseudolites. Due to the presence of multiple objects, the multipath effect is significant, which impacts the receiver and total navigation performance. On the other hand, the system we are trying to build requires a random placement of the pseudolites and a random trajectory path of the receiver, which may lead to the near-far problem. Therefore, the impact of the multipath and of the near-far problem when multipath is present is not fully assessed. This paper will discuss the theoretical characteristics of the multi-carrier and multi-code navigation system by looking first at the receiver’s performance due to the multipath, geometry, and dynamics impact. The impact of other important parameters such as carrier frequency, code length and type, chipping rate, data rate, noise and transmitted power are discussed in the paper.
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	1434 - 1467
Cite this article:	Progri, Ilir F., Michalson, William R., "An Alternative Approach to Multipath and Near-Far Problem for Indoor Geolocation Systems," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 1434-1467.
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