Suppression of Noise Amplitude Modulation Interference in Triangle Frequency Modulation Detector Based on FrFT

The target detection problem for a triangle wave frequency modulation (TWFM) detection system in the presence of the noise amplitude modulation (NAM) interference is considered in this paper. The range measuring principle based on Chirp Z Transform (CZT) and velocity measuring principle based on Moving Target Detection (MTD) are respectively introduced. Exploiting the observation that the NAM interference often affects the TWFM detector's detection performance, we present an anti-interference method based on Fractional Fourier Transform (FrFT) to suppress the NAM jamming. Simulations show that the method proposed in this paper can excise the NAM interference effectively. Moreover, all proposed methods are realized by FPGA for the first time, and then the outside field experiments verify the feasibility of these techniques.