THINNED STEPPED FREQUENCY WAVE-FORMS TO FURNISH EXISTING RADARS WITH IMAGING CAPABILITY

Introducing imaging capability to an existing radar, even if it is a h igh RF bandwidth radar, may be difficult, due to limitations on the IF bandwidth, limitations on the pulse repetition frequency and electrom agnetic compatibility problems. This paper discusses the use of thinne d stepped frequency waveforms, which enable the radar to switch betwee n RF frequencies to provide a synthesized wide RF bandwidth, while the thinning may alleviate some of the constraints imposed on the radar. Random and periodic thinning are discussed in the first part of this p aper. However, thinning may cause degradation in image quality, thus a n additional technique - Sequence CLEAN deconvolution - is suggested. Sequence CLEAN is an iterative deconvolution algorithm, adopted from t he field of Radio Astronomy, which is capable of resolving close targe ts in a dense environment, where the system response is heavily affect ed by high sidelobes.