Parameter estimation and target detection in a distributed-clutter environment

A requirement for the simultaneous measurement of range and velocity of a radar target (parameter estimation) can be satisfied by using a waveform with a thumbtack-type ambiguity diagram and implementing a bank of matched filters in the absence of distributed clutter. It is demonstrated here that this technique cannot be applied in a distributed-clutter environment, because it provides no subclutter visibility for detecting targets. To eliminate nonmoving clutter, a moving-target-indicator (MTI) delay-line canceler must be used on all Doppler-filter outputs. This scheme suffers from blind-speed problems and prevents parameter estimation with a single pulse. To data no known technique based on a single pulse can achieve parameter estimation in distributed clutter. It is shown that in such an environment, with two or more pulses an MTI system using equal and oppositely range-Doppler-coupled waveforms not only simplifies the required hardware with no blind-speed problem but also provides subclutter and accomplishes accurate parameter estimation simultaneously.