InSAR
Access our easy to use cloud solution so you can monitor, measure and detect deformation of land surfaces over time and be automatically alerted to customer defined exceedances to a precision of 1-2 millimetres. Typically, we find that this data is difficult to access and desktop based reporting in GIS is often hard.
Interferometric Synthetic Aperture Radar (InSAR) is a remote sensing technique used to detect, monitor and measure the magnitude of deformation in land surfaces over time utilising Synthetic Aperture Rader (SAR) imagery. This imagery can be sourced from radar equipped satellites at regular intervals with active sensors capable of seeing through rain & cloud at any time of the day or night with millimetre accurate changes. Understanding the extent and magnitude of such movement such as landforms created by erosion, helps to identify and manage risk of potential failures and provide assurance that the area is safe and stable. Where ground based monitoring is not available, InSAR provides a means of remotely monitoring landform features such as stockpiles, landfill, infrastructure, urban and tailings facilities. Working with 3VG to utilise radar signals from earth-orbiting satellites, Decipher provides a way to visualise displacement (cm) on an interactive map to enable users to identify specific areas of deformation across a broad range of interest. Decipher analysis tools also allow users to then chart the details along a transect line or a single point over time. This also includes the ability to view historical imagery to show areas of deformation.
How InSAR works
1. SAR Image Acquisition
Selected satellites transmit pulses of radar to Earth’s surface along their Line of Sight (LOS) and measure the backscattered energy. This radar, or microwave energy, can penetrate rain and cloud and works day or night.
2. Amplitude & Phase
SAR images are characterised by 2 factors. The amount of terrain and roughness of the surface recorded in the radar signal makes up the amplitude, while the phase looks at the reflecting distances between ground surface and satellite.
3. Ascending & Descending Orbits
Satellites travel from north to south (descending) or south to north (ascending), while the Earth rotates East to West, enabling two angles of data acquisition in a single area; Horizontal and Vertical deformations.
4. Interferograms
The difference between phase measurements derived from SAR is displayed digitally, also known as an interferogram or INSAR.
5. Displacement Map
Combining the two or more InSAR images over time provides timeseries data insights of movement and change in the Earth’s surface.
How we process the Imagery
1
Historical Data Acquisition
Client defines areas of interest, date range of required historical datasets for ingestion.
2
Dual versus Single Look
Client selects Dual or Single look imagery.
3
Satellite Imagery Monitoring
Synthetic-aperture radar (SAR) imagery from Sentinel is provided via our imagery partners in the form of pre-processed data as soon as it becomes available. Commercial grade imagery can be accessed on request.
4
Google Processing
Data is cleansed and optimised for analysis and is ingested into Google Earth Engine (GEE) to allow Decipher users to dynamically analyse the data they’re interested in.
5
Visualise & Report
Users can visualise displacement data on the map and highlight areas of interest/concern using transect line and comparison points. Timeseries data is also displayed in chart form, available for export.
6
Technical investigation
Where a more thorough, technical analysis of explanation is required, Decipher’s data providers can provide a range of additional technical services & products.
7
Real World Application
Make data-driven decisions to implement effective change and management strategies to a project
