Glossary.
Plain-English definitions of the terms used in satellite airport ground monitoring.
- InSAR
- Interferometric Synthetic Aperture Radar. A method that compares radar satellite images of the same place taken at different times to measure small ground movements over large areas.
- SAR
- Synthetic Aperture Radar. A satellite radar that makes images day and night and through cloud.
- Sentinel-1
- A European Copernicus radar satellite mission with free, regular coverage of Europe. A common starting point for PoCs.
- Ground subsidence
- Gradual sinking of the ground surface, often caused by soft or reclaimed soils compressing over time.
- Uneven (differential) settlement
- When parts of a site sink by different amounts. It can crack pavements and affect drainage.
- Reclaimed land
- Land created by filling in sea, river or lake areas. Many coastal airports are built on it.
- Freeze–thaw
- Repeated freezing and thawing of water in the ground, which can lift and drop soils and pavements in winter.
- Grid cell
- TOWER splits an airport into 90 m cells and assesses each one on every update.
- Flagged cell
- A cell TOWER’s AI suggests checking first. It is a suggestion, not a confirmed defect.
- Unassessed cell
- A cell TOWER could not assess reliably for that period, for example because of snow or missing data.
- Revisit time
- How often a satellite passes over the same place. TOWER updates every 12 to 15 days.
- Apron
- The area of an airport where aircraft park, load and refuel.
- PoC
- Proof of Concept. A first project to test TOWER at an airport before an annual subscription.
- EGMS
- European Ground Motion Service. A free Copernicus service that publishes ground motion data for Europe.
Related pages
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We hope to start with public satellite data at your airport: no equipment, a screening report first, then field checks with your team.