This paper demonstrates the application of the Gaussian mixture model technique for separation of phase centres in an area containing the aggregate of scattering centres at multiple distances from the SAR sensor. Typically co-polar phase differences have a unimodal gaussian distribution over a diffuse scatterer with high interchannel coherence. This paper shows that in special conditions the phase difference distribution is multimodal with stable mean values and standard deviation over time, indicating correspondence to the separation of coherent scattering centres over the target area.