Coherent integration for maneuvering target detection via fast nonparametric estimation method.

• The proposed method can simultaneously correct the complex DFBs with a one-step process of matrix multiplication, thereby simplifying the corrections of different order DFBs. • The improved time-scaled transform is proposed to correct the linear RCM without searching the Doppler ambiguity number. • The proposed method achieves well-focused result without searching and estimating the target's unknown parameters. • The proposed method is simple to implement and computationally efficient. Maneuvering target presents a great threat for radar detection applications. The complex unknown motions between radar and maneuvering target seriously affect the performance of target coherent integration. Existing methods utilizing parameter search or estimation are limited by the high computational burden and the propagation errors of different parameter estimations. In this study, a fast nonparametric estimation method is proposed for coherent integration of maneuvering target. Firstly, the second-order Keystone transform is adopted to eliminate the quadratic range cell migration (RCM). Secondly, the modified range frequency reversal process is proposed to simultaneously remove the complex low- and high-order Doppler frequency broadenings (DFBs) by a one-step matrix multiplication operation. Subsequently, the residual RCM is corrected by the proposed improved time-scaled transform without searching for the Doppler ambiguity number, and then a well-focused result can be obtained. The proposed method is simple to implement and computationally efficient given that searching and estimation of parameters are avoided. It also addresses the high-order DFB and blind speed sidelobe. The processing results of simulated and real data are presented to verify the performance of the presented approach. [ABSTRACT FROM AUTHOR]