基于瞬时相关频域检测的复合调制引信定距方法

For the radio fuze combining chaotic code bi-phase modulation with linear frequency modulation, a ranging method based on instant correlation frequency domain detection is proposed to achieve precise ranging for the ground targets with different scattering characteristics. Before instant correlation in time domain, the local chaotic code and the target echo signal are sampled synchronously with code width as sampling period; to reduce the influence of the target echo signal amplitude on ranging method, target distance and speed information are extracted by Two-Dimensional Fast Fourier Transform (2D-FFT), three feature quantities of the instant correlation window position, harmonic envelope main lobe position and stable Doppler frequency are used as the ranging basis, and precise ranging is achieved in frequency domain. Simulation results show that the judgement results of ranging method are only related to the signal-to-noise ratio of the target signal, regardless of the magnitude of the signal amplitude, and it can achieve precise ranging of the hybrid modulation radio fuze for the ground targets with different scattering characteristics in the circumstance of a very low signal-to-noise ratio -28 dB.