The Research Of TDOA Estimation Based On Satellite Associated Location

Electronic warfare is dominant in modern information war. The passive localization of the enemy interference is an extraordinary important branch in electronic warfare countermeasures. To localize the position of local radiation source fast and with high precision is the key factor in winning the electronic countermeasures, either for enemy or ourselves. In this paper, we introduced the satellite-carried passive location system which is widely applied in military and civilian areas. Additionally, we researched the estimation of time delay parameters of the localization system in deep.In this paper, we first introduced the background of satellite-carried passive location system, as well as the research status and development trend in home and abroad. Then, the basic mentality of system model and system works on satellite-carried passive location technique was introduced, as well as the geometry principle of satellite-carried passive location system works. Meanwhile, we introduced several major factors that influence the precision in this localization system model.In this paper, we focused on the estimation of TDOA in satellite-carried passive localization. Several algorithms were analyzed and derived, including the generalized cross correlation method improved from basic correlation, the method based on cross ambiguity function, and the TOC-CHTS method based on the combination of Hilbert transform and high-order cumulants. In practical applications, due to that all the estimation schemes can only compute one time delay value for a group of data, the result of computation may have a large error and the algorithm stability cannot be guaranteed because of noise and some characteristics of the signal. Hence, we proposed an improved scheme based on wavelet transform and data clustering analysis. The proposed scheme can transform the group of data that contain the time delay information into wavelet domain, which can result in multiple groups of data. Computing the time delay of each group of data, combined with deleting the singular point using data clustering analysis, the final estimation can be obtained. In this paper, the improved scheme of TOC-CHTS is named as WT-TOC-CHTS. In addition, for the case that the objective signal is narrow-band digital modulated signals, we introduced the TDOA estimation based on phase method aiming at the problem that it costs too much for transmitting localization data in real environment. To deal with its defect of inferior performance in anti-noise, we proposed a TDOA estimation scheme based on shift invariance wavelet threshold denoising. In the novel scheme, we first denoise the signal using wavelet threshold denoising method based on shift invariance, then optimized the denoising effect using zero-cross detecting. At last, we obtained the estimation of TDOA in frequency domain employing the characteristics of narrow-band signals. Finally, the simulation results verified the effectiveness and feasibility of the novel scheme proposed in this paper.At last, we concluded the research works in this paper, stated that there still had several problems required to be study deeply, and looked ahead the further works in the near future.