APSIS™

APSIS™ (Advanced Pixel System using Intermittent SBAS) is Terra Motion's patented InSAR processing technique, developed in partnership with the University of Nottingham, for measuring ground motion and land subsidence from satellite Synthetic Aperture Radar (SAR) imagery. Traditional InSAR methods fail over many rural, vegetated and remote surfaces; APSIS exploits intermittent coherence to measure relative surface movement from a few millimetres to several centimetres per year across urban areas, agricultural land, forests and other natural terrain, without ground control or corner reflectors.

For each customer area of interest, Terra Motion collects and processes a stack of Sentinel-1 radar images (at least 30 per analysis; Radarsat and higher-resolution SAR data are also supported). Outputs are high-resolution GeoTIFF rasters of average velocity and full time series, resolved into vertical and east-west components where ascending and descending data are available, ready for open-source and commercial GIS. Analytics such as hotspot detection, time-series classification and change-point detection screen the results, and risk maps identify historic movement, heave and subsidence and potential landslides around assets.

Engineering teams, consultancies and asset owners use it to assess and monitor civil structures and linear infrastructure such as roads, railways, bridges, pipelines and dams, as well as mining operations and tailings storage facilities. In defence, it detects ground movement caused by underground excavation such as tunnels.

Investor Nottingham Technology Ventures reports clients among environmental and geophysical consultancies, water utilities and infrastructure owners, uses including water leak detection, and more than 10,000 km² of analytics processed each month.