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Journal of Applied Mathematics
Volume 2014 (2014), Article ID 107156, 10 pages
http://dx.doi.org/10.1155/2014/107156
Research Article

Urban and Indoor Weak Signal Tracking Using an Array Tracker with MVA and Nonlinear Filtering

1College of Automation, Harbin Engineering University, Harbin 150001, China
2The Unit 92941, PLA, Huludao 125000, China

Received 4 May 2014; Accepted 17 June 2014; Published 2 July 2014

Academic Editor: Yuxin Zhao

Copyright © 2014 Jicheng Ding et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We focus on the need for weak GPS signal tracking technique at a receiver powered on in urban or indoor environment; the tracking loop is unlocked and data bit edge position is unknown. A modified Viterbi algorithm (MVA) based on dynamic programming is developed and it is applied to GPS bit synchronization to improve bit edge position detection probability. Meanwhile, two combination carrier tracking schemes based on central difference Kalman filter (CDKF) and MVA module are designed for tracking very weak GPS signal. The testing results indicate that the methods can successfully detect bit edge position with high detection probability whether or not the tracking loop is locked. The tested combination tracking scheme is still able to work well when the signal quality deteriorates to 20 dB-Hz without additional large store space.