Date of Award

2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Electrical and Computer Engineering

Committee Chair

Laurie Joiner

Committee Member

Reza Adhami

Committee Member

Emil Jovanov

Committee Member

Yuri Shtessel

Committee Member

Kyle Siegrist

Subject(s)

Radar--Design.

Abstract

This dissertation presents the design and analysis of a short range radar sensor that utilizes a novel compound waveform. Compound waveforms consist of a combination of more than one type of traditional radar waveform. Unique to this work is the manner in which the phase of the compound waveform composed of linear frequency modulation and bi-phase code modulations are combined. The phase of the modulations is combined on an intra pulse basis with the sweep duration of the linear frequency modulation matched to the period of the bi-phase code. The frequency bandwidths of the component modulations are also matched. Combining modulations enable radar waveforms that have the desirable characteristics of each modulation. Advances in direct digital frequency synthesis, microwave/radio frequency and field programmable gate array technologies enable the generation of repeatable, highly linear frequency sweeps and provide a means for accurate application of phase codes to linear frequency modulations. An analysis of the component modulations that form the compound phase coded linear frequency modulation is performed. The resulting compound phase coded linear frequency modulation is compared with the component modulations to demonstrate the performance improvement that is achieved by the combining of radar waveform modulations enabled by modern digital frequency synthesis techniques. The compound phase coded linear frequency modulation waveform shows improved range resolution and suppression of range sidelobes over the individual component waveforms. The phase coded linear frequency modulation shows an improvement of 13 dB over the linear frequency modulation and is only 2 dB less than the phase code. It also achieves a 5 and 10 nanosecond narrower mainlobe autocorrelation peak than the phase code and linear frequency modulation, respectively. A notional signal processing architecture of the waveform is simulated to demonstrate the ability to process the compound waveform. Experimental data collected from a direct digital frequency synthesis based arbitrary waveform generator is compared with the simulated waveform. The compound waveform model and the experimental results show good agreement.

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