Research On Signal Processing Related Problems Of Low Power Aperture Product Radar

Reducing the probability of radar interception can improve the survivability of radar in an electronic countermeasures environment.This thesis proposes a radar system for transponder detection.The radar system consists of three parts: the transmitting station,the air forwarding station and the ground receiving station.The forwarding station is responsible for receiving and forwarding the target echo signal,and the receiving station is responsible for receiving the communication of the forwarding signal and signal processing.The radar system reduces the transmission power aperture product by shortening the transmission distance of the target echo,thereby reducing the intercept probability of the radar.This thesis refers to this new system radar as low power aperture product radar.This thesis first introduces the working principle of low power aperture product radar system,and compares the pattern and signal-to-noise ratio of phased array mode and MIMO mode.By analyzing the power aperture product and interception distance of low power aperture product radar and single base radar,the low intercept probability performance of low power aperture product radar is verified.According to the preset requirements of low power aperture product radar,this thesis calculates the detection factor and positioning accuracy of the radar system.Then,this thesis introduces the arrangement of the transmitting array and the forwarding station receiving array of the low power aperture product radar,the transmitting signals of the MIMO mode and the phased array mode,and the different communication transmission modes of the forwarding station,and obtains the echo signal model.The low power aperture product radar detects the target by forwarding the signal to the forwarding station.The traditional code division multiplexing operation is large and the function of the forwarding station is high,while the traditional frequency division multiplexing takes up a large bandwidth and the amplitude and phase error.In this thesis,a frequency division modulation method is proposed in this thesis,which can effectively solve the above problems in traditional communication transmission.Finally,this thesis discusses the signal processing method for receiving signal of low power aperture product radar.The received signal contains a direct power signal with strong power.This thesis discusses the method of time synchronization and frequency synchronization using direct wave,and the suppression process of mainlobe direct wave and sidelobe direct wave.The simulation results verify the effectiveness of direct wave synchronization and direct wave suppression.The existing communication transmission method is applied to the signal processing of the radar system.The simulation results show that the traditional code division multiplexing signal processing method can obtain accurate direction of arrival,while the traditional frequency division multiplexing cannot accurately measure the reception angle due to the amplitude and phase error of the filter.Aiming at the newly proposed frequency division multiplexing modulation method,this thesis introduces the corresponding signal processing methods and respectively applies them in MIMO mode and phased array mode.The feasibility of the method is verified by simulation.The method has the advantages of small calculation and small error,and is more suitable for low power aperture product radar.