Moving target detection by quadrature mirror filter

For pulse radars, coherent moving target indication processes and discrete Fourier transform-based Doppler filter banks are used to separate moving targets from stationary objects and clutter. These processes utilize the Doppler frequency shift of the moving target. Because the moving target indication processes and Doppler filter bank processes are performed with the pulse repetition period as a unit, several pulses are required to obtain output from the filter bank. If the search radar considered here uses an electronically scanned antenna, the fact that several pulses are required for one steered beam means that search capability is limited (e.g., the searchable region is narrowed). A method is proposed here that uses the quadrature mirror filter with a range cell as the process unit for the Doppler filter process for high-speed target Doppler separation to reduce the number of pulses required for each beam. The quadrature mirror filter is a filter that performs the orthogonal wavelet transform. This original signal can be separated without wasting information in the time-frequency domain. Long transmitted pulses are used in computer simulations to show that the number of pulses needed in the Doppler filter bank can be reduced using this method.