Study On Target Localization Methods Based On Pseudo-Doppler Antennas

With the development of modern wireless communication technology, the number of wireless communication devices and the density of spectral coverage increased significantly. Some sudden or malicious radio interference may cause huge property losses to the users; Terrorists and insurgents will also use wireless signal to communicate or distribute illegal information, which threats the safety of person and property of the people. As a key technology in wireless signal monitoring, signal localization plays an important part in interference localization, illegal signal detection and suspicious signal tracking.As a kind of widely used direction-finding antenna, pseudo-Doppler antenna has low facility complexity, less cost and high accuracy. Its single-channel bearing estimation ability enables signal monitor personnel to localize signal source by distribute two or more pseudo-Doppler antennas.It also cooperates well with other kinds of antennas.However, when the received signal frequency doesn’t match the antenna’s size, the bearing-estimation result will have phase ambiguity, other than that, traditional pseudo-Doppler localization method is less robust under stable distribution noise than Gaussian noise, and as an AOA based localization method, It will lose its efficacy in non-line-of-sight(NLOS) environment. This thesis did a thorough research on above issues, proposed two optimized localization methods in line-of-sight(LOS) environment, and one localization method suitable for NLOS environment, details are as follows:Firstly, an AOA-TDOA combined pseudo-Doppler localization method is proposed, which overcomes the phase-ambiguity issue using phase interferometer database matching. Both simulation and real experiments show that the method has high localizing accuracy.Secondly, a particle filtering based dual-station pseudo-Doppler localization method is proposed. The method employs particle filtering approach to jointly estimate both AOA of the two stations, then applies a non-linear mapping to acquire the source’s location, forming an integration of AOA calculation and dual-station localization. Simulations demonstrates that the proposed method is much more robust than the traditional method with stable distribution noise.Finally, an optimized pseudo-Doppler localization method based on signal fingerprint database matching is proposed to cope with NLOS environment. This thesis also built an radio propagation simulation platform with .Net Framework based on ray-tracing theory. Integrated simulations including signal emitting, signal reception, signal analyzation, fingerprint abstraction, fingerprint database generation and source localization are performed on this platform, results show that the proposed method achieves a high localization accuracy in NLOS environment.