Insar Surveying

Fugro employs state-of-the-art remote sensing techniques to detect and monitor a wide range of ground and structure deformation, both in the past and the present. These surveys are accomplished using space-borne interferometric synthetic aperture radar (InSAR) processing of radar images acquired by satellites such as ERS-1/-2, Envisat, Radarsat-1/-2, ALOS, and TerraSAR-X and can be accomplished for both large-area or site-specific assessments. InSAR is capable of detecting millimeters to meters of deformation spanning months, years, and even decades, and provides a unique information source that is highly complementary to conventional ground surveying.

Products and Services

• Conventional Differential InSAR (DifSAR). DifSAR maps relative surface deformation occurring in the temporal period spanned by two radar images, and can be applied to study deformation related to a wide variety of activities and events, both natural and anthropogenic. DifSAR can provide a continuous field of deformation information and is capable of detecting deformation ranging from centimeters to meters and can map and monitor extremely large areas (thousands/square km). DifSAR surveys can be used to map historical events using archive radar images (dating back to 1992) and monitor sites at regular intervals through programming of new radar image acquisitions.
• Persistent Scatterer InSAR (PSI). PSI is an advanced differential interferometric technique involving the processing of a collection of multi-temporal radar images (typically 20 or more) to identify networks of persistently reflecting ground features (such as buildings, bridges, infrastructure and rocky outcrops), against which precise (millimetric) measurements of motion can be made. PSI typically yields hundreds of persistent scatterer (PS) points per square km, providing a virtual differential GPS network. The method is best suited to mapping subtle deformation (millimeters to decimeters per year) primarily over urban and semi-urban areas and can be used to assess extremely large areas (e.g., entire cities), specific structures (e.g., power stations) and more localized features (e.g., tunneling routes).
  
  PSI is unique in its ability to reconstruct historical deformation trends through the processing of large archives of radar images (dating back to 1992) and can also be used to monitor sites at regular intervals through programming of new acquisitions of radar imagery.
• Artificial Reflector InSAR (CAT/CRInSAR): Networks of artificial radar reflectors are deployed in regions of low natural radar response (e.g., rural settings) and at specific points across structures such as dams, embankments, underground water reservoirs, pipelines and landslides. The reflectors respond strongly to the satellite radar signal allowing for precise, remote monitoring of site stability. Two types of artificial radar reflectors are available:
  
  1. Compact Active Transponders (CATS) – exclusive to Fugro
     • Active radar transponder
     • Compact units (shoebox sized)
     • Respond to both ascending and descending pass of satellite
     • Respond to multiple satellite look angles
  2. Corner Reflectors (CRS)
     • Passive radar reflector
     • Trihedral metallic structures (~1m)

Activities

Oil & Gas Onshore oil & gas fields / reservoirs Underground gas storage Installations & key infrastructure Pipeline Health, safety, security and environment (HSSE) Mining Active & historical mining sites Groundwater recharge Civil Engineering & Construction Urban stability Building settlement Tunneling Development Infrastructure (e.g., railways, roads, bridges) Asset management Environment Global warming / climate change Coastlines Water (sustainable water extraction, groundwater recharge) Flood risk (key infrastructure, flood risk modeling) CO2 sequestration Environmental impact assessment (EIA) ground and stability Public Utilities Energy (pipelines, infrastructure) Transportation (roads, railway) Airports Ports Water (pipelines, reservoirs, and dams) Communication Geohazards Earthquake Volcanoes Landslides Subsidence Slope stability

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