Modulated stepped frequency radar is a system to get high-resolution range profile with the problem of redundancy.So extracting method is presented to eliminate such redundancy and get the true position of target.In this radar system

target motion is the main factor to influence its performance.Characteristics of extracting method are analyzed here

so do the effects of velocity and velocity estimated error on this method.In order to overcome the influence of return pulse motion

an improved extracting method is provided.The capability of this improved method is good with accurate velocity estimation

but decreases with increasing velocity estimated error.The velocity estimated error limit is addressed to reduce the problem caused by it as far as possible.In addition

an amplitude interpolating method is given to resolve the range-coupling shift caused by velocity estimated error.The emulated computer results validate the correctness of theory analysis.These two suggested methods

especially the later amplitude interpolating method

can settle the key problems of target moving in the signal processing of modulated stepped frequency radar and provide foundation for realization of such radar system.