Multi-radiation Source Passive Radar Signal Processing And Simulation Study

Different from conventional radar, the passive radar is based on opportunity illuminators. Not utilizing the outer electromagnetic wave, the passive radar takes advantage of signals emitted by broadcast station,TV station as transmit signal to detect the target such as aircrafts and missiles. The target direction, distance and speed can be estimated,so that the targets can be identified and tracked. The advantages of passive radar can be listed as follows: On the one hand, the external illuminators are civil signal which is distributed widely and can not be estimated and destroyed easily. On the other hand, it is useful to improve the survivability of passive radar and decrease the interference possibility. Last, passive radar is beneficial to detect the objects such as stealth targets and smaller targets by the lower frequency of most external illuminators.Multi-illuminators passive radar makes use of multiple FM broadcast signals as transmit signal. After the signal processing of each FM broadcast echoes and coherent accumulation processing, the detection ability of stealth and smaller objects could be enhanced.In this thesis, the processing methods of multi-illuminators passive radar signal are investigated, and the main researches focus on the following issues:First, the principles and characteristics of multi-illuminators passive radar are studied and analyzed. Besides, the improvement ability of multi-illuminators passive radar over the traditional radar on object detection is investigated.Second, the FM broadcast's characteristic and form are analyzed and investigated. The ability of object detection between different broadcast signals is compared. It is pointed that there is a method to sample signals efficiently with no signal distortion. Further more, the digital down convert technique based on orthogonal transformation is especially pointed and analyzed. It is also discussed that adaptive beam forming can eliminate the direct path signals in the target echo signals. The ambiguity function between direct path signals and target echo signals is called as Doppler correlation processing. Through deducing, we can learn that it is a key point in the signal process.Third, the results of coherent accumulation of multiple FM broadcast signals are analyzed and the research on the target detection principle of multi-transmitters passive radar is presented. What is more, the comparison of detection improvement between coherent integration and non-coherent integration is made. By making simulation, the superior of multi-illuminators passive radar in target detection aspects is demonstrated. In the same time, CFAR detection is analyzed and verified by simulation.Last, the simulation platform building of multi-illuminators passive radar is introduced, which includes signal generating, transmitting, processing and detecting modules. The DDC processing, the Doppler correlation processing and CFAR detection are realized and investigated especially. The key simulation results of multi-illuminators passive radar are also given.