Abstract
Radar plays an increasingly important role in target detection because of its all-weather detection capability. Furthermore, to detect weak and flexible target, effectively coherent integration method is required in radar signal processing to enhance the target signal intensity. Based on the Radon-Fourier transform (RFT) algorithm, which is widely used to solve the problem of weak target detection, range migration and Doppler ambiguity in low signal-to-noise ratio (SNR) environment, an improved multiple pulse repetition intervals (PRIs) RFT (MRFT) coherent integration method is presented in this paper. The method adopts the Linear frequency modulated (LFM) signal with three different PRIs as the transmitted signal, then combines with the RFT outputs of three RPIs to enhance the target energy and suppress the blind speed side lobe (BSSL) caused by RFT. Meanwhile, the design rules and constraints of this method are also discussed in detail. The experiments with simulation data and real measured data are provided to demonstrate that the designed method can get better BSSL suppression capability and higher detection rate than conventional methods.
Highlights
In radar signal processing, long-time signal integration can effectively improve the signal-to-noise ratio (SNR) of the system and improve the detection ability of low observable targets
PROPOSED IMPROVED MRFT COHERENT INTEGRATION METHOD Aiming at the limitations of the 2RFT method, we proposed an improved MRFT method with three alternately transmitted pulse repetition intervals (PRIs), i.e., T1, T2 and T3, where T1 > T2 > T3
The theoretical analysis shows that the different blind speed determines the blind speed side lobe (BSSL) of Radon-Fourier transform (RFT) outputs appears in different locations
Summary
Long-time signal integration can effectively improve the signal-to-noise ratio (SNR) of the system and improve the detection ability of low observable targets. Reference [16] proposed a method based on random repetition intervals, this method solves the velocity ambiguity and BSSL suppression problems via adding random jitter on uniform PRI. Aiming at the above problems, this paper proposes an improved multiple pulse repetition intervals RFT (MRFT) method This method uses multi-PRIs Linear frequency modulated (LFM) signals as transmitted radar signal and jointly processes the RFT outputs in different PRIs. By compensating the target’s range migration in different PRIs, the locations of BSSL should not overlap due to the properly designed PRI. Because the target has been compensated to the same location in different PRIs, the minimizing and maximizing operations should have little effect on target’s main lobe, this method can preserve the coherent integration gain improved by RFT processing.
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