A MISO Frequency Diverse Array Implementation

Estimating the spatial angle of arrival for a received radar signal traditionally entails measurements across multiple antenna elements. Spatially diverse Multiple Input Multiple Output (MIMO) emission structures, such as the Frequency Diverse Array (FDA), provide waveform separability to achieve spatial estimation without the need for multiple receive antenna elements. A low complexity Multiple Input Single Output (MISO) radar system leveraging the FDA emission structure coupled with the Linear Frequency Modulated Continuous Wave (LFMCW) waveform is experimentally demonstrated that estimates range, Doppler and spatial angle information of the illuminated scene using a single receiver antenna element. In comparison to well-known spatially diverse emission structures (i.e., Doppler Division Multiple Access (DDMA) and Time Division Multiple Access (TDMA)), LFMCW-FDA is shown to retain the full range and Doppler unambiguous spaces at the cost of a reduced range resolution. To combat the degraded range performance, an adaptive algorithm is introduced with initial results showing the ability to improve separability of closely spaced scatterers in range and angle. With the persistent illumination achieved by the emission structure, demonstrated performance, and low complexity architecture, the LFMCW-FDA system is shown to have attractive features for use in a low-resolution search radar context.