Covert, Intelligent, and Spectrally-Efficient MIMO-Based Noise Radar Networks

The following tasks were accomplished: (1) Distributed adaptive beamforming using noise waveforms: The use of multiple radars for characterizing the radar cross section (RCS) of the target was investigated, and the RCS enhancement was quantified. A framework for inducing orthogonality in sequences and in polarization was developed to differentiate signals from various transmitters. Generalized Likelihood Ratio Test (GLRT) and Tapped Delay Line (TDL) beamforming were integrated. (2) RF tag approaches: The concept of using notched frequency sub-bands within the ultrawideband (UWB) noise waveform was assessed to identify re-reflections from different tags. Using an array of notched tags around the target, it was possible to infer target orientation. A system design for communication between radar and RF tags using UWB noise waveforms is proposed. (3) MIMO-based networking: A scheme for embedding multi-hop communication mechanism within the MIMO noise radar system was investigated for networking purposes. Orthogonal Frequency-Division Multiplexing (OFDM) was employed for communications, which was then inserted into notched sub-bands of the UWB noise signal. Multi-radar networked operation was proposed.