Detection,and parameter estimation of LPI signals in passive radar

It is desired for multi-static passive radar to intercept target radar signals simultaneously during the process of location which utilize the difference time of arrival (DTOA). However, many LPI techniques are adopted by airborne radar in practice such as low side lobe method and narrow beam technique. As a result, receivers will not locate in the coverage of major lobe simultaneously. One is covered by the main beam while others located in the side lobe of the antenna. Therefore the difference of signals' strength between these receivers will be more than 20dB. The strong signal intercepted by the receiver in the main beam is analyzed by auto-correlation theory, and signal's periodicity is estimated. Then we take it as replica of the side lobe signal to define the model of mixing product. Furthermore, mixing product signal which has no relations to do with the modulation of signal is deduced. Finally, an example of real data process which validated its effectiveness in application is given.