High resolution radar profiling using higher-order statistics

摘要

A coherent radar is used for achieving high resolution radar imaging of a moving object in sea clutter and noise. A stored replica of the transmitted waveform is combined with the returned signal in a synchronous detector to produce in-phase and quadrature (I and Q or complex) samples. High resolution is achieved by transmitting a series of pulses, each at a different frequency, and then processing these complex samples to produce a synthetic down-range profile. To enhance the radar target or object from system noise and sea clutter, the complex I and Q (in-phase and quadrature component) samples from the radar are coherently averaged in a special two-dimensional slice of the trispectrum (e.g. quadruple product or fourth-order moment). This formulation of the fourth moment retains all important target information and suppresses Gaussian noise. Once averaged, a new set of I and Q samples are reconstructed that produce the same trispectral slice as this average. These reconstructed samples are then transformed using conventional Fourier transform methods to produce the average, or enhanced, down-range profile.