Interferometric Synthetic Aperture Radar (InSAR for short), detects and measures displacement over time. The technology is based on the comparison of multiple radar (SAR) image pairs.
The use of radar to detect the velocity of a moving object is commonly used in many well known applications: by the military to detect the speed of an approaching aircraft, in baseball to measure the speed of the pitcher’s fastball, and by law enforcement to determine whether your car is speeding.
Benefits of using InSAR:
- High Precision: ability to detect 1 – 2 mm of displacement per year;
- Large Area Coverage: images (areas of analysis) that are 1500+ km² each;
- Dense Data Coverage: typically generate tens of millions of data points per area of interest;
- Remote Sensing: no ground instruments or in-person inspections required;
- Full Site Monitoring: often detects displacement in areas of unknown risk;
- Measurement Frequency: updated displacement measurements after each satellite revisit (typically every 2 – 12 days).
Satellite Options
| Satellite | Band | Precision | Vegetation | Resolution1 | Image Footprint (WxL)2 | Revisit Time (days) |
| TerraSAR-X (TSX) | X | 2 mm. | Poor | 3 m | 30 km x 50 km | 4 – 11 |
| Cosmo (CSK) | X | 3 mm. | Poor | 3 m | 40 km x 40 km | 4 – 16 |
| Sentinel | C | 4 mm. | Moderate | 20 m | 250 km x 250 km | 6 – 12 |
| Radarsat-2 | C | 4 mm. | Moderate | 3 m | 20 km x 20 km | 24 |
| ALOS-2 | L | 2 mm. | Excellent | 3 m | 55 km x 70 km | 14 |
| SAOCOM | L | 2 mm. | Excellent | 10 m | 55 km x 70 km | 8 |
1Resolution depends on the beam mode chosen for the monitoring program and can range from 50cm to 20m.
2Footprint size depends on the beam mode chosen for the monitoring project and may differ from those listed.