Temporarily Coherent Scatterer Analysis for Monitoring Changing Infrastructure

Conventional InSAR time series methods constrain pixel selection to scatterers maintaining coherence across the entire observation period, preventing monitoring of newly constructed or demolished infrastructure. We present a method for estimating the displacement time series of Temporarily Coherent Scatterer (TCS) pixels implemented in the free and open-source research software SARvey that overcomes this limitation for changing infrastructure.

The TCS approach detects significant changes in the SAR signal time series with a coherent change detection method that exploits the phase noise level of a scatterer. The phase noise is estimated from the spatial neighbourhood which is also used to estimate each pixel's coherent lifetime from the period before and after the change. Displacement time series are then retrieved within each pixel's coherent lifetime from a small baseline interferogram network allowing to retrieve transient displacement signals.

Validation over Miami, USA (239 Sentinel-1 ascending images, track 48, April 2016–June 2025) demonstrates accurate detection of both, construction and demolition, of high-rise buildings along the coastline, validated against high-resolution optical satellite imagery. Post-construction settlement rates confirm previously reported infrastructure displacement patterns.

SARvey's TCS implementation combines automated change detection with robust time series inversion, delivering displacement maps for structural health monitoring and risk assessment. The modular, open-source framework supports multi-mission SAR data (Sentinel-1, TerraSAR-X). The methodology presented in this work contributes to overcoming the critical gap in operational InSAR services in case of changing environments.