Joint range-Doppler resolution limit for multi-pulse radar based on scattering information

Abstract

Resolution limits are essential tools in the evaluation of parameter system performance. However, there is very limited literature that deals with the resolution limit for joint estimation of multi-parameters. In this paper, we employ thoughts of information theory to propose a joint resolution limit (JRL) for range and Doppler shift estimation in multi-pulse radar. Based on the general multi-pulse radar model, the closed-form expression of scattering information is derived for two targets with complex Gaussian scattering properties. A critical state is selected where the quadrature component of the scattering information is 1 bit and corresponding intervals of range and Doppler shift are defined as the JRL. Under the assumption of adjacent targets, the closed-form approximation for the JRL is obtained by a second-order Taylor series, which illustrates that there exists interference between range and Doppler shift. In addition, explicit range resolution limit and explicit Doppler shift resolution limit are derived as special cases of the explicit JRL. These resolution limits are general and are not based on any specific resolution method. Numerical simulations are performed to validate the validity of the proposed resolution limits.