An adaptive matched filter

A recursive estimator providing the best linear mean square estimate of an arbitrary signal is derived in a form which is readily implemented using a charge coupled device (CCD) realization of the sliding chirp-z-transform (CZT). This estimator forms the basis of the adaptive matched filter which is being developed for electro-optical sensor applications. A microprocessor is utilized to calculate the frequency domain filter characteristic based on updated noise spectrum estimates. In this manner, the filter characteristic is changed to maintain matched performance. The frequency domain characteristic is converted to a finite impulse response in the time domain via an inverse CZT. The impulse response and the signal to be filtered are used as inputs to a CCD analog-analog correlator to perform the matched filtering in the time domain.