- Volume 24 Issue 2
Velocity Estimation of Moving Targets by Azimuth Differentials of SAR Images
SAR 영상의 Azimuth 차분을 이용한 움직이는 물체의 속도측정방법
- Park, Jeong-Won (Department of Earth System Sciences, Yonsei University) ;
- Jung, Hyung-Sup (Department of Earth System Sciences, Yonsei University) ;
- Won, Joong-Sun (Department of Earth System Sciences, Yonsei University)
- Published : 2008.04.30
We present an efficient and robust technique to estimate the velocity of moving targets from a single SAR image. In SAR images, azimuth image shift is a well blown phenomenon, which is observed in moving targets having slant-range velocity. Most methods estimated the velocity of moving targets from the distance difference between the road and moving targets or between ship and the ship wake. However, the methods could not be always applied to moving targets because it is difficult to find the road and the ship wake. We propose a method for estimating the velocity of moving targets from azimuth differentials of range-compressed image. This method is based on a phenomenon that Doppler center frequency shift of moving target causes a phase difference in azimuth differential values. The phase difference is linearly distorted by Doppler rate due to the geometry of SAR image. The linear distortion is eliminated from phase removal procedure, and then the constant phase difference is estimated. Finally, range velocity estimates for moving targets are retrieved from the constant phase difference. This technique was tested using an ENVISAT ASAR image in which several unknown ships are presented. In the case of a isolated target, the result was nearly coincident with the result from conventional method. However, in the case of a target which is located near non-target material, the difference of the result between from our algorithm and from conventional method was more than 1m/s.
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