Time Difference Of The Passive Location Of The Radar Signal Extraction

Time difference of arrival (TDOA) location system, namely the hyperbola location, is an important passive location method.Using the time difference of signals arrived to three or more different stations, we can determine the position of the target wanted to be located.Because of its high precision and fast location advantages, it is widely used in practice.But its precision depends on time delay estimation, so researching fast and exact time delay estimation method become a hot topic in TDOA location system.The special radar signal environment is very complex in electronic warfare, so the received signals always have low signal noise ratio (SNR) and complex model.Under this kind of environment, the estimation precision of time delay and the capability of restraining noise fallen down in the conventional methods.Most radar signals are non-stationary signals, but they are cyclostationary signals,namely, the correlation function of radar signals is periodic function of time. Based on the cyclostationary characteristic, a novel time delay estimation method has been proposed in this thesis.The reseach work focused on the time delay estimation of the common practical radar singnals, including harmonics signal, chirp signal, polynomial phase signal, and phase-shift keying signal.The new algorithm for different radar signals are deduced in detail respectively, and simulation results are presented.The results proved that the new method is efficient for time delay and some other parameters estimation. At the same time, it can restrain multiplicative and additive noise.Generally, a nice idea and method are proposed for radar signal processing. Meanwhile, there is still a lot of work worth further research with great effort.