Real-time frequency and 2-D angle estimation with sub-Nyquist spatio-temporal sampling

An algorithm is presented for real-time estimation of the frequency and azimuth and elevation angles of each signal incident upon an airborne antenna array system over a very wide frequency band, 2-18 GHz. The algorithm provides unambiguous frequency estimation despite severe temporal undersampling necessitated by cost/complexity of hardware considerations. The algorithm also provides unambiguous azimuth and elevation angle estimation over the entire 2-18 GHz bandwidth despite severe spatial undersampling at the higher end of this bank necessitated by mutual coupling considerations and resolving power requirements at the lower end of the band. Simulation results are presented demonstrating the capabilities of the algorithm.<>