Doctoral Dissertations

Date of Award

5-1992

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Electrical Engineering

Major Professor

Daniel B. Koch

Committee Members

Bouldin, Crilly, Harris, Pace

Abstract

Phase coding and linear frequency modulation, either in analog or in discrete form, have been used in the past for pulse compression in peak power limited radar systems to achieve high range resolution. In recent work, a hybrid coded waveform, which uses phase coding together with frequency stepping, has been shown to improve range resolution. Pulse compression techniques have existed for quite some time, but the impact of operating conditions on their resolution performance has not been reported in the open literature. A major objective of this dissertation has been to fill this void by providing the resolution performance results in the presence of noise, target fluctuation, and channel fading for a few popular and efficient non-hybrid as well as hybrid coded radar pulse compression waveforms from the resolution standpoint.

This dissertation investigates non-hybrid PN sequences, Frank, and complementary coded waveforms, as well as frequency-stepped PN sequences and complementary coded hybrid waveforms. The resolution performance of these pulse compression methods have been evaluated for various combinations of statistical models which include noise, target fluctuation, and channel fading as may be encountered in a practical situation.

A few analytical results, and a large amount of simulation data relating the performance of the pulse compression methods to a wide class of practical situations have been provided in this dissertation. It is concluded that for all of the coding methods, non­ hybrid and hybrid, a chip-to-chip amplitude variation is more detrimental at high noise level than at low noise level. In contrast, a scan-to-scan amplitude variation causes more degradation at low noise level than at high noise level.

Among non-hybrid coding methods, complementary codes generally outperform the Frank and PN sequence codes, with the PN sequence codes having generally been found to demonstrate the worst resolution performance. The effect of codelength on the resolution performance of non-hybrid codes has also been investigated. In general, the statistical models qualitatively affect the hybrid coded waveforms in the same way as they affect non-hybrid coded waveforms. Finally, hybrid complementary coded waveforms always have better resolution performance than hybrid PN sequence coded waveforms.

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