This paper introduces a new algorithm for denoising SAR images. It is directly applicable to Sentinel-1 GRD images, without the need for single-look complex operations. The algorithm builds on the non-local patch matching idea for statistical denoising, similar to the SAR-BM3D and NL-SAR algorithms, but introduces two corrections : 1. A non-uniform prior for the reflectance values is used for the patch matching, thus allowing a better fit to the data, and 2. Denoising is performed in singular values space, with a prior distribution of expected "clean" singular values learned and transfered from optical images. The denoised SAR images show reduced amount of speckle compared to alternative methods.