| dc.description.abstract | Multiple-input multiple-output (MIMO) radar has been receiving increasing attention in recent
years due to the dramatic advantages offered by MIMO systems in communications. The
amount of energy reflected from a common radar target varies considerably with the observation
angle, and these scintillations may cause signal fading which severely degrades the performance
of conventional radars. MIMO radar with widely spaced antennas is able to view several
aspects of a target simultaneously, which realizes a spatial diversity gain to overcome the target
scintillation problem, leading to significantly enhanced system performance. Building on the
initial studies presented in the literature, MIMO radar is investigated in detail in this thesis.
First of all, a finite scatterers model is proposed, based on which the target detection performance
of a MIMO radar system with arbitrary array-target configurations is evaluated and
analyzed. A MIMO radar involving a realistic target is also set up, whose simulation results
corroborate the conclusions drawn based on theoretical target models, validating in a practical
setting the improvements in detection performance brought in by the MIMO radar configuration.
Next, a hybrid bistatic radar is introduced, which combines the phased-array and MIMO radar
configurations to take advantage of both coherent processing gain and spatial diversity gain
simultaneously. The target detection performance is first assessed, followed by the evaluation
of the direction finding performance, i.e., performance of estimating angle of arrival as well
as angel of departure. The presented theoretical expressions can be used to select the best
architecture for a radar system, particularly when the total number of antennas is fixed.
Finally, a novel two phase radar scheme involving signal retransmission is studied. It is based
on the time-reversal (TR) detection and is investigated to improve the detection performance
of a wideband MIMO radar or sonar system. Three detectors demanding various amounts
of a priori information are developed, whose performance is evaluated and compared. Three
schemes are proposed to design the retransmitted waveform with constraints on the transmitted
signal power, further enhancing the detection performance with respect to the TR approach. | en |
