Performance Analysis and Simulation of Weak GPS Signal Acquisition and Tracking

Ruihui Di

Abstract:	Under normal conditions, GPS signal strength is about - 160dBW within a bandwidth of about 2.046MHz while the thermal noise is about -141dBW at room temperature. When a GPS receiver is operating inside a building or in an urban canyon, the buildings will block and attenuate the GPS signals. At this situation, improving the sensitivity of GPS signal processing is always desirable. Signal sensitivity is important issue for GPS signal processing in the forest, building or in city canyon. In the present paper, coherent and non-coherent integration methods are used for weak signal acquiring and tracking. In the phase of developing the signal processing algorithms, it is not optimal to use real sampled data which was obtained from the GPS antenna through an RF front end, because it is impossible to control or to know the properties of the received signals. In order to solve this problem, we can use simulated data. Implementing such a GNSS signal simulator has also been presented in the paper. Multi-path is the result of reflected signal interfering with the direct line-of-sight signal and is a dominant source of error in weak GPS signal acquiring and tracking. We can use Multi-path Signal Collection technology to make the dispersive signals together. The purpose of doing so is to utilize the weak signals to fulfill GPS signal acquiring. In addition to what have been stated as above, several new methods to acquire weak GPS signals are proposed in this paper, such as chaos theory, and so on. Some performance with respect to weak GPS signals, such as, multi-path effect, anti-jamming effect, the feasibility of using weak GPS signals for high dynamic systems, the factors affecting weak GPS signal acquiring and tracking, etc., have also been studied. The paper will present the detailed analysis about weak signal processing.
Published in:	Proceedings of the 63rd Annual Meeting of The Institute of Navigation (2007) April 23 - 25, 2007 Royal Sonesta Hotel Cambridge, MA
Pages:	595 - 601
Cite this article:	Di, Ruihui, "Performance Analysis and Simulation of Weak GPS Signal Acquisition and Tracking," Proceedings of the 63rd Annual Meeting of The Institute of Navigation (2007), Cambridge, MA, April 2007, pp. 595-601.
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