Implementation and Analysis of an Efficient Dual-Beam Radar-Communications Technique

Fully digital arrays enable realization of dual-function radar-communications systems which generate multiple simultaneous transmit beams with different modulation structures in different spatial directions. These spatially diverse transmissions are produced by designing the individual wave forms transmitted at each antenna element that combine in the far-field to synthesize the desired modulations at the specified directions. This thesis derives a look-up table (LUT) implementation of the existing Far-Field Radiated Emissions Design (FFRED) optimization framework. This LUT implementation requires a single optimization routine for a set of desired signals, rather than the previous implementation which required pulse-to-pulse optimization, making the LUT approach more efficient. The LUT is generated by representing the waveforms transmitted by each element in the array as a sequence of beamformers, where the LUT contains beamformers based on the phase difference between the desired signal modulations. The globally optimal beamformers, in terms of power efficiency, can be realized via the Lagrange dual problem for most beam locations and powers. The Phase-Attached Radar-Communications (PARC) waveform is selected for the communications waveform alongside a Linear Frequency Modulated (LFM) waveform for the radar signal. A set of FFRED LUTs are then used to simulate a radar transmission to verify the utility of the radar system. The same LUTs are then used to estimate the communications performance of a system with varying levels of the array knowledge uncertainty.