SIGNALS AND PROCESSING FOR RANDOM SIGNAL RADARS
Abstract
Previous studies performed at Purdue University show that certain advantages exist for radars using signals possessing random components. Analytical studies and experimental verification have been carried out for radars using Gaussian bandlimited noise, digital delay-lines, and polarity coincidence correlations. While these efforts demonstrate the potential of the concept, the implementations employed suffer several performance liabilities. This research develops signals and associated processing techniques which improve the performance, simplify the implementation, and are more amenable to adaptive operation for radars using the random signal concept. These goals are accomplished through the use of a signal set that is composed of a deterministic spreading function, a binary random or pseudo-random noise source, and a possibly random or pseudo-random pulsing sequence. The detection performance of this signal set and associated processing configuration are determined and it is shown that large increases in this performance may be achieved in pulsed radars using peak amplitude limited transmitters as compared to previous random signal radar implementations. This is accomplished without the highspeed sampling required by the earlier implementations. The resolution and clutter performance of the proposed signal set are investigated by the use of an extended ambiguity function. The performance in clutter is shown to be improved by over 3 dB with respect to a comparable classical random signal radar implementation. Techniques are developed for determining the parameters of the spreading function that result in signals with desirable ambiguity functions and high effective power. These techniques are based on the use of window functions for sidelobe control and the theory of chirp waveforms for effective power enhancement. It is shown how pseudo-random binary noise generators may be used to remove the long digital delay-lines required in earlier implementations. The removal of these delay-lines and the high-speed samplers and quantizers, and the relaxation of certain filtering requirements considerably simplifies the implementation of radars using the random signal concept. The proposed signal set and processing configuration is shown to be quite amenable to adaptive operation.
Degree
Ph.D.
Subject Area
Electrical engineering
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