Radar technology was developed to detect distant targets.The missile-borne radar processes echo signals to achieve the speed measurement and ranging of moving targets.The “long distance,low observable and high speed maneuvering” of weak moving targets make it difficult for traditional detection methods to identify,detect and track them.In order to improve the detection ability of such targets,signals are often be integrated.However,due to the movement of the target,the across range unit effect and Doppler frequency migration effect will be produced in the long-time integration of signal.The echo model construction of rectilinearly moving targets with uniform velocity and acceleration is studied,and the items that cause the ARU (across range unit) effect are analyzed.To analyzed the effect of the range walk compensation,the simulation of first-order and second-order Keystone algorithm is compared.The CZT-IFFT (Chirp-Z transformation-inverse fast fourier transform) method is selected to realize the second-order Keystone algorithm,correcting the range curvature and range walking,and the signal-to-noise ratio gain of different correction methods are compared.