Abstract:

Considering the resolution of the radar array is an important performance measure for the directions-of-arrival (DOA) estimation algorithm, the minimum separation resolution limit (MSRL) from the perspective of the CramérRao bound （CRB） is deduced based on the non-uniform linear array model and different signal-to-noise ratios. First, closed form expressions of the CRB about the unknown parameters (electric angle and the noise variance) under two sources farfield signal model are derived. On this basis, the analytical expression of separation resolution limit is established by relating the resolution limit with the CRB. Through some mathematical approximate processing, an explicit analytical expression of this distance resolution limit is derived under orthogonal and non-orthogonal conditions. Simulation results verify the correctness of the theory. This conclusion can be used as the primary standard to evaluate the design of nonuniform array and performance of DOA estimation algorithm.