Research On Key Technology Of TDOA-Based Location For JTIDS Signal Source

Combined with signal characteristics and location conditions, two key technologies in JTIDS signal passive TDOA location, namely time delay estimation (TDE) and position solution, especially low cost and easy engineering realization, are investigated in the thesis, which meet the requirement. In the end, according to the selected methods of TDE and location solution, the location system is designed by modularizations and evaluated by location precision. Main work is listed as follows:1. Considering the different measures dealing with signal of location station, TDE methods are divided into two categories. One is the method of TDE based on cross correlation, and the other is the method of TDE based on signal detection. In the former sort, several methods, such as cross-correlation TDE, general cross-correlation TDE, cyclic spectrum TDE, higher-order cross-bispectrum TDE and LMSTDE, are analyzed and simulated using JTIDS signal. The conclusion is that these TDE methods can give an accurate estimation, but the computation complexity is high and the engineering realization is difficult.2. The latter method with the use of the pulse characteristics aims at solving above deficiencies. Three methods are studied for the detecting part, the critical part of the method, such as method of TDE based on most correlation, method of TDE based on self-correlation signal detection algorithm and method of TDE based on higher-order statistic. Theoretical analysis and simulation results are given, which indicate the method of TDE based on self-correlation signal detection algorithm is better than others not only in the precision of TDE but in the computation complexity and the hardware realization.3. Factors related with the precision of location are studied, and location accuracy GDOP figures are given on the different conditions of different location precisions, arrangement ways and location station numbers, which can provide theories on the base distribution of location system. In addition, combined with the application of JTIDS signal, a novel method of TDOA location, namely Hyperbola Asymptote Least Square location method (HA-LS), is proposed. Compared with the traditional location algorithms, simulation results indicate that the proposed method can obtain better performance especially in the short base line location applied in the situation of the work. Meanwhile, the amount of computation is low and the engineering realization is easy.4. On the basis of studies, the passive TDOA location system design chart and performance evaluation figure are given which indicate the availability and validity of the system.Finally, summary is carried on about the work and an outlook for future is given.