Explicit Joint Resolution Limit of Range and Direction of Arrival Estimation for Phased-Array Radar

Abstract

Phased-array technology can greatly enhance radar surveillance strategies and has become an attractive candidate for the next generation radar. Resolution limit is a critical performance indicator in phased-array radar systems. However, when it comes to estimating multiple parameters, the resolution limit has not been fully explored. This paper uses information theory to establish joint resolution limits (JRL) for range and direction of arrival (DOA) estimation in phased-array radar. In Swerling 1 model, we obtain the explicit scattering information of the duo-target whose amplitudes are the same. A threshold condition is picked in which the scattering information’s quadrature part equals one bit, and relevant parameters separations are determined to be the JRL. The explicit JRL is obtained by Taylor expansions, which illustrates that the JRL depends on several key parameters, including the number of elements, the signal-to-noise ratio, and the ratio of signal bandwidth to carrier frequency. Moreover, we demonstrate that the JRL degrades to the range/DOA resolution limit if the separation of DOA/range is zero. Finally, we validate the JRL through numerical simulations.