In image processing of high-resolution sliding spotlight SAR, it is important to know the Doppler rate with accuracy; however, traditional Doppler rate estimation algorithms are not very helpful because of the azimuth spectrum folding phenomenon. In this study, an algorithm that works on the transposition domain is proposed to solve this problem. Furthermore, the algorithm is also helpful in obtaining excellent focused images by embedding it in the two-step technique. Finally, the proposed algorithm is verified using computer simulations.