Nested array with time-delayers for target range and angle estimation

Since a nested phased array cannot directly estimate the range of targets due to range ambiguity, this paper proposes a nested array with diverse time-delayers for target range and angle estimation. The essence is to construct a new array structure by systematically nesting two uniform linear arrays through diverse time-delays which yields a range-dependent receiving array beampattern. Using second-order statistics of the received data, it is capable of providing a dramatic increase of the system degrees-of-freedom which means more sources can be resolved. More importantly, target range and angle can be estimated by exploiting the range-dependent array beampattern. The performance improvements are evaluated by examining the Cramér-Rao lower bounds.