Te c h n o l o g y
Using the latest techniques to monitor railway infrastructure Simon Abbott from Network Rail and Matthew Bray from SatSense discuss the technology driving earthworks asset management
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magine knowing how much the ground was moving around your line, embankment, station, bridge or tunnel from the comfort of your desk. It was the vast untapped potential of highresolution ground movement data from radar satellite, using a technique known as InSAR, that was the calling for Matthew Bray to take up the post of Chief Executive Officer of SatSense. InSAR, or interferometric synthetic aperture radar, is a remote sensing technique which uses multiple radar images to detect changes in surface deformation down to rates of 1mm/year. The InSAR dataset is automatically updated every six days and stored for online access by customers and partners. The nature and frequency of this data means it may be possible to identify and highlight areas of the railway that are subject to progressive movement, enabling a more effective treatment of risk by Network Rail. This could lead to less disruption and improved passenger safety. “We are passionate about helping people to understand what’s happening on the ground, and structures on the ground,” said Matthew, who is still amazed at the broad appeal of such a niche technology. “In essence we provide information from satellite data to help people figure out how their area of interest and structures on the ground are moving. The use of satellite data means we can cover large geographic areas such as entire countries and continents.” Freely available data The raw satellite radar data is freely available from the European Space Agency’s Sentinel-1 satellite constellation. SatSense’s know-how coupled with recent technological developments means it is now possible to apply this data to user cases such as rail, highways and utilities. It has caught the attention of Network Rail. The organisations are working together to determine how the data could help in the management of the organisation’s 190,000 earthwork assets, which includes the likes of slopes, embankments and railbusinessdaily.com
cuttings – excavations in the ground composed of rock and soil. “Earth observation techniques are something being talked about more and more today,” said Simon Abbott, Network Rail’s Professional Head of Geotechnics. “That’s a good thing because there’s an opportunity there to change the way that we look at infrastructure within the realms of what is practicable from those types of technologies.” Using the InSAR technique, radar images with a standard resolution of 4 by 14 metres can cost effectively cover tens of thousands of square kilometres, making it suitable to monitor ground movements across a large range of spatial scales. “Rail is an ideal candidate for our technology and the team have been talking to Simon at
Network Rail since the very early days of the company in early 2018,” said Matthew, who joined SatSense as CEO just as the country went into lockdown in March. “Our technology is well suited to rail because it is remote sensing, covering large geographic areas that include the rail corridor and the adjacent land, without having to send staff on site – i.e. fewer boots on the ballast. Artificial reflectors can be installed where natural signals are insufficient. “We’ve struck a good relationship with Simon and he’s put us in touch with his team of geotechnical and mining engineers. Working alongside Simon and his team we can identify the information that is of most benefit by applying our bespoke algorithms to the raw InSAR data.” January 2021 | 59
