Michael Bryant (Committee Member), Robert Penno (Committee Member), Kuldip Rattan (Committee Chair), Michael Wicks (Committee Member), Zhiqiang Wu (Committee Co-Chair), Xiadong Zhang (Committee Member)
Doctor of Philosophy (PhD)
As electromagnetic spectrum availability shrinks, there is growing interest in combining multiple functions, such as radar and communications signals, into a single multipurpose waveform. Historically mixed-modulation has used orthogonal separation of different message signals in different dimensions such as time or frequency. This research explores an alternative approach of implementing an in-band, mixed-modulated waveform that combines surveillance radar and navigation functions into a single signal and demonstrates the feasibility of this approach for a limited area navigation solution. The first contribution of this research is the use of reduced phase-angle binary phase shift keying (BPSK) along with overlapped (channelized) spread-spectrum phase discretes based on pseudorandom noise sequences to encode multiple messages in a single pulse. The goal is to determine if these signals can achieve satisfactory message performance in a radar pulse while minimizing the effect on radar performance. For the purpose of this research, radar performance will be evaluated in terms of power spectral density, matched filter auto-correlation for target detection, and the ambiguity function. The second contribution is the development of an algorithm that permits the use of received navigation messages with non-synchronous times of arrival. Numerical simulations of the resulting iterative, non-synchronous geolocation algorithm demonstrate rapid convergence of the estimated and true trajectory despite large temporal differences in message time of arrival.
Department or Program
Ph.D. in Engineering
Year Degree Awarded
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