Persistent Scatterer (PS) InSAR

Persistent Scatterer (PS) InSAR, also called Coherent Target Monitoring (CTM), is an InSAR stack processing technique that uses multiple images taken at regular intervals to achieve improved measurement results. Stack processing allows surface movement to be determined by the temporal variation of phase for each pixel over time.
CTM allows the detection of pixels dominated by a stable large reflector called a persistent scatterer. InSAR measurements from these large coherent targets provide more accurate results than those using pixels with many small distributed scatterers. Both techniques are useful and can be used together.

CTM is well suited to areas that have strong reflectors such as man-made objects (buildings, metal structures, etc.) or natural objects (rocky terrain). CTM is also well suited to monitoring installed corner reflectors (CRs) which are the ideal point reflector.

This technique produces excellent results in areas with strong and persistent scatterers. This is true even in terrain where the surface texture is continually changing, such as forest or muskeg covered areas, where wide area monitoring of distributed scatterers may not produce useful results.

In terrain favourable for wide area monitoring of distributed scatterers, CTM can also provide results over point targets in the area, resulting in two separate sets of complimentary measurements.

CR and CTM Cumulative Vertical Deformation