SYNTHETIC APERTURE RADAR (SAR)

Part of our Data Acquisition, Data Delivery & Analytics Solutions

Synthetic Aperture Radar (SAR) is an advanced form of radar used to create high-resolution images of landscapes, objects and structures. Unlike traditional optical imaging systems, SAR operates by emitting microwave signals and capturing their echoes as they bounce off of the Earth’s surface. This allows SAR to function effectively during both day and night.

What is Synthetic Aperture Radar?

The term “synthetic aperture” refers to the technique of stimulating a large antenna (or aperture) by moving a smaller antenna over a target area and combining the signals received over time. This motion enables SAR systems to achieve the resolution of a much larger antenna, providing detailed imagery from airborne or spaceborne platforms, such as satellites and drones.

SAR systems measure the time delay and strength of the returned signals to construct two-dimensional (and sometimes three-dimensional) images. These images can be used to detect surface changes, measure terrain elevation, monitor deforestation, track ice movements and assist in disaster response. One key feature of SAR is its ability to perform interferometric SAR (InSAR) which involves comparing images from different times to detect minute surface deformations, useful for applications like earthquake or volcano monitoring.

Two workers dressed in hi vis clothing and a white and blue hard hat, controlling a SAR drone that is set out on the ground, with trees and a pale cloudy sky in the background.
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How Does SAR Operate?

SAR operates in different frequency bands (e.g. C, L, P bands), each offering has unique advantages in terms of resolution and penetration capabilities. For example, longer wavelengths can penetrate vegetation and are better for geological observations.

Because of its ability to collect data under challenging conditions and it’s high-resolution capabilities, SAR has become a vital tool in Earth observation, environmental monitoring and remote sensing. As technology evolves, SAR systems are becoming more compact and accessible, expanding their role in scientific research, commercial applications and national security.

One such example is the UAS-Based Multiband Synthetic Aperture Radar service, offered by our Applied Technologies department and partners Surveyar and Radaz.

Key Benefits

World’s first simultaneous use of multiband SAR on a single UAS platform

Depth: greater ground penetration in the P-band

Multiband allows for tomographic techniques

Increased resolution over spaceborne platforms

Bespoke flight planning to suit mission parameters

World’s first simultaneous use of multiband SAR on a single UAS platform

Depth: greater ground penetration in the P-band

Discrimination of above and below ground biomass

Multiband allows for tomographic techniques

Increased resolution over spaceborne platforms

Bespoke flight planning to suit mission parameters

UAV Multiband SAR Applications

The advancement of Synthetic Aperture Radar (SAR) has significantly transformed the geotechnical industry by enabling high-resolution, all-weather, and day-and-night monitoring of ground conditions and infrastructure. Modern SAR techniques, such as Interferometric SAR (InSAR), allow engineers to detect millimetre-scale surface deformations over large areas, making it invaluable for monitoring landslides, subsidence, and the stability of slopes, embankments, and foundations. This has improved risk assessment and early warning systems, particularly in urban environments and around critical infrastructure like dams, tunnels, and transport networks. 

 

Additionally, the integration of satellite-based SAR data with geotechnical modelling and GIS platforms has enhanced decision-making by providing continuous, cost-effective, and non-invasive monitoring compared to traditional ground-based methods. As satellite constellations expand and data processing becomes more advanced, SAR is playing an increasingly central role in predictive maintenance and resilience planning within the geotechnical field.

Actionable Insights Above Ground, Below Ground & Through Time

Voids

  • Burrowing animals
  • Shallow mine workings
  • Karst geology and sinkholes

Structures & Buried Objects

  • Foundations
  • UXO detection
  • Archaeology investigations

Soil Moisture – Tomography

  • Flood plain analysis
  • Agricultural studies
  • Peatlands studies
  • Geotech slope investigations
  • Spoil tip run off studies

Biomass – Tomography

  • Forestry and agriculture studies
  • Height and canopy
  • Biomass and leaf and stem
  • Biomass below ground
  • Invasive and indicator species
  • Crop health studies
  • Below canopy habitat
  • Biodiversity and carbon capture assessments
Geophysics