500-800
km altitude
1
mm/yr precision
100.000
measurements/km²
60
measurements/year
Millimeter precision measurements of height changes
Track minute height changes over areas as large as a country or as small as a building.
WHY INSAR
Up to weekly satellite observations
Monitor all relevant movements in high detail with up to 60 measurements per year.
100,000 measurements/km²
Imagine the possibilities with this measurement density compared to conventional techniques.
Access deformation history back to 1992
Investigate historical movements for retrospective fact-finding and long-term modeling.
Independent & off-site solution
Prevent costs and risks of on-site personnel. No artificial targets required.
Easy access and use of large datasets
Choose your access method with our flexible and cost-efficient cloud platform.
Radar satellites
Scientists have long used radar data from satellites, but only recently it is making a splash in industry. Radar is a particularly useful tool because it is able to function throughout all weather conditions, as well as day and night. It is also able to accurately detect small movements to a couple of millimeters precision per measurement, for example the movements caused by ground deformations. With many active radar satellites and more on the way, operational use of these technologies are now possible.
The radar satellites record the radar’s reflections that the earth, buildings and objects generate. By comparing multiple recordings of the same area or object, we can measure millimeter-level changes in height. The radar’s reflections depend on surface characteristics and are best for solid objects such as urban areas, roads or bare earth.
Rather than owning our own satellites, we can access all major public and private satellite constellations providing data for commercial use. Satellites differ in resolution, the time between measurements, the measurement history already built up, as well as costs. All of these factors go into our consulting process, to determine which satellite data is best for your application.
Measuring deformation
The radar satellite sends out a sinusoidal radar signal to the Earth and measures the reflection. This reflection has two components:
- The amplitude: the strength of the reflection. This is visually interpretable.
- The phase: the fraction of a full sinusoidal wave cycle at the moment the signal is received by the satellite. This looks random.
Both components are essential for InSAR measurements, but using the phase makes them so accurate.
The radar satellite measures the phase values of all the objects in the area it flies over. After the satellite has passed over that same area for the second time, we can compare the phase values. When a certain object moves (e.g. the house in the image below), the satellite signal’s travel distance changes, resulting in a phase difference between the two satellite acquisitions. Because we now accurately know the phase difference, we can compare it to the length of a full wave cycle in order to determine the deformation with high precision. This is called InSAR.
Because the house is subsiding, the satellite signal has to travel a longer distance in the second acquisition. This results in a phase difference that can be accurately translated into a deformation value.
The InSAR technique is useful for comparing two images, but its real strength lies in deformation time series. With up to 60 observations per year, minute deformation dynamics can be monitored over areas as large as a country or as small as an individual building. Next to that, by using InSAR time series we can better model disturbances and thereby increase the measurement precision.
InSAR data is new and different and requires a different view than conventional measurements techniques. Consulting support is therefore included in every contract. Allow us to help you apply our data to your business case.