This variant of radar interferometry is characterized by the highest possible accuracy of displacement estimation (2–4 mm in height). Input data for processing should be at least 20-25 images of the same territory for different dates, made in the same geometry of the satellite radar survey.
1.Selecting the main image
2. Registration of images of the interferometric chain with an accuracy of 1/100 pixel
3. Construction of interferograms for each pair of images
4.Evaluation of the magnitude of coherence / standard deviations of the amplitude of each pair of images
5.Determination of points - stable scatterers of the radar signal
6 Estimation of phase differences and multi-time phase sweep for point targets using previously determined points
7.Application of a special filter that removes the influence of the atmosphere on the interferometric phase
The result of processing is a vector file of points, the attributes of which are written:
- offsets for each shooting date;
- average annual rate of displacement;
- the total value of the displacements;
- height above the WGS-84 ellipsoid.