The echo of stepped-frequency pulse series for the point target with rotation

as well as the micro-motion’s influence on one-dimensional range profile

is analyzed in detail.The time-range profile can be synthesized by utilizing slow-time correlations between frames.The varying laws of the range for the rotary point target and the target position in range profiles are contrastively analyzed.Based on this time-range profile

a novel feature extraction method of wideband micro motions is presented

and the theoretical expressions of micro-motion parameters

such as rotation center

rotation radius and angle velocity

are given.The theoretical precision of the micro-motion feature extraction method is deduced.Finally

to verify the results

the outfield experiments of two reflectors with symmetrical rotations are successfully designed and operated for the ground-based millimeter stepped-frequency radar.The idea can be extended to the feature extraction of multiple kinds of motions for stepped-frequency radar

such as vibration and tumbling

and can be adopted in other high resolution radar systems with linear frequency modulation signals.