Signal Processing And Implementation For JTIDS-based Passive Bistatic Radar

As a bistatic/multistatic radar system,passive radar realizes the detection,positioning and tracking of the target by passively receiving the external electromagnetic radiation source.Since passive radar has the advantages of strong concealment,anti-interference,low-altitude detection and anti-stealth,it has broad development prospects.As a TDMA information distribution system,JTIDS combines communication,navigation and identification,it is a joint tactical information distribution system used by the US military and its allies to command operations in wartime.Because of the high transmitting power and wide wartime coverage of JTIDS signal,it is beneficial to the detection of distant targets and construction of radar warning network as the illumination of passive bistatic radar.This paper takes US military JTIDS signal as the irradiation source to study the method and implementation of radar target detection.The main work is summarized as follows:1.The passive bistatic radar target detection method using JTIDS signal is studied.To solve the problem of multi-path clutter in the signal received by echo channel,block lattice adaptive filtering is used to suppress multi-path clutter in this paper.Three typical timedomain adaptive algorithms are studied.Aiming at the problem of Doppler spread of multipath clutter in real environment,an improved block lattice adaptive filtering method is proposed,which can effectively suppress the spread multi-path clutter near zero frequency.Consider that JTIDS signal ambiguity function has side peaks in Doppler dimension,this paper adopts the Doppler side peak suppression method based on mismatch filtering.This method uses the characteristic of fixed Doppler dimension side peak interval to suppress Doppler side peak and thus improve target detection performance.Aiming at the problem of large amount of data calculation in the process of coherent accumulation,this paper uses the combination of CIC and HB to achieve high-efficiency anti-aliasing filtering.Compared with direct FFT and conventional low-pass filtering methods,it can greatly reduce complex multiplication and improve computing efficiency.2.The GPU implementation technology of JTIDS passive bistatic radar signal processing is studied.Considering that the block-lattice adaptive filtering algorithm contains a large number of vector operations,the clutter suppression is updated iteratively according to the order of the filter,and the forward and backward prediction errors of the same order at different moments are simultaneously calculated in parallel.The prefix and solution method,which is time-consuming,are implemented.For the secondary peak suppression,the reference signal is segmented firstly;secondly,the optimal solution of each segment of the signal is solved simultaneously by opening up a two-dimensional grid block;finally,the Gaussian elimination method is used to complete the matrix inversion processing.For Range-Doppler correlation,the sliding matrix is constructed in advance,and reasonable grid thread blocks are allocated to maximize the utilization of GPU resources.In addition,the anti-aliasing filtering method is implemented by decimation and filtering at the same time.The calculation of redundant data is avoided,and an efficient implementation of the algorithm can be obtained.