GLEN EAGLES - INVESTIGATING BEAVER BURROWS
Key Project Details
Location: Gleneagles and Pitlochry, Scotland
Client: Network Rail
Sector: Rail
Services: Multiband SAR Drone Survey
In February 2025, Central Alliance (CA) was tasked by Network Rail (NR) Scotland to conduct two airborne drone-based multiband synthetic aperture radar (SAR) surveys over two sections of rail on the Highland Main Line (HGL2) a few kilometres south of Pitlochry and the Bog Wood and Meadow Special Site of Scientific Interest (SSSI) by the Scottish Central Main Line (SCM4) close to Gleneagles.
The surveys were part of an ecological study of beavers in the local area, suspected of burrowing into Network Rail infrastructure. An airborne remote sensing inspection method was necessary to quantify the extent of beaver burrowing and assess if the rail, and moreover the beavers, were in any immediate danger.
Beavers were first reintroduced to Scotland back in May 2009 as part of the original “Scottish Beaver Trial” in Knapdale Forest in Argyll by the Royal Zoological Society of Scotland and were given European Protected Species Status in 2019. Since then, beaver populations have expanded from their home in Argyll to Tayside and many points in between, including the sites by Gleneagles and Pitlochry.
Network Rail ecologists decided to execute the SAR technique for Gleneagles and Pitlochry following a previous burrow investigation trial performed in Coupar Angus by Applied Technologies’ own Thomas Goldsby-West and Thomas Davies in February 2024.
The Synthetic Aperture Radar (SAR) technique is an active geophysical remote sensing survey method which utilises the generation of microwaves to image the surface of the Earth, even in poor visibility or the hours of darkness. In partnership with William Kirk’s SurveyAR, and Brazilian radar developers Radaz, Central Alliance conducts SAR surveys all around the world with the RD350 Multiband SAR system aboard a DJI Matrice 600 Pro Drone.
The RD350 is the only combined C, L and P band UAS radar on the market, with the only system in the UK currently in use by Central Alliance. The simultaneous use of the multiple frequency bands, C and L allows the surveyor to define topography, and moreover investigate the near subsurface with the lower frequency P band.
Network Rail defined the target areas with an ecological reconnaissance visit, and final flight missions were designed and agreed with Central Alliance to investigate both areas for beaver burrows using a combination of linear and helical flight patterns 120m above ground.
In Rail Week 48 of the Financial Year 24/25, Applied Technologies’ lead UAS pilot Adrian Pawsey and Adrian’s colleague as the Spotter, made the journey to the Cairngorms and Ochil Hills to fulfil this mission, joined by SurveyAR Director William Kirk and Network Rail Project Manager and Ecologist James Morrison.
Ten Multiband SAR flights were completed over both sites: six helical missions and four linear missions.
Using the data acquired in the field, radar experts Radaz processed the raw field data into GeoTIFFs showing plain and cross polarized data for the C, L and P bands; CVV, LHH, LHV, PHH, LVV and LVH.
A convoluted neural network analysis was performed on the deeper penetrating P band data to discern the presence of, and moreover classify, any beaver burrows occupied, collapsed or partial, present on the site.
The analysis of Gleneagles shows there are currently up to a potential of seven actively inhabited beaver burrows, stretching down to depths of two metres.
As a research platform, the drone-based SAR platform continues to impress and is growing continuously with methodological improvements being implemented in the field, and advances in technological capability on the processing side.
Following the Network Rail Beaver project, SurveyAR and Central Alliance next look to Kintore, Aberdeenshire, where the team will investigate a site for badger setts, using a similar methodology presented above.
In February 2025, Central Alliance (CA) was tasked by Network Rail (NR) Scotland to conduct two airborne drone-based multiband synthetic aperture radar (SAR) surveys over two sections of rail on the Highland Main Line (HGL2) a few kilometres south of Pitlochry and the Bog Wood and Meadow Special Site of Scientific Interest (SSSI) by the Scottish Central Main Line (SCM4) close to Gleneagles.
The surveys were part of an ecological study of beavers in the local area, suspected of burrowing into Network Rail infrastructure. An airborne remote sensing inspection method was necessary to quantify the extent of beaver burrowing and assess if the rail, and moreover the beavers, were in any immediate danger.
Beavers were first reintroduced to Scotland back in May 2009 as part of the original “Scottish Beaver Trial” in Knapdale Forest in Argyll by the Royal Zoological Society of Scotland and were given European Protected Species Status in 2019. Since then, beaver populations have expanded from their home in Argyll to Tayside and many points in between, including the sites by Gleneagles and Pitlochry.
Network Rail ecologists decided to execute the SAR technique for Gleneagles and Pitlochry following a previous burrow investigation trial performed in Coupar Angus by Applied Technologies’ own Thomas Goldsby-West and Thomas Davies in February 2024.
The Synthetic Aperture Radar (SAR) technique is an active geophysical remote sensing survey method which utilises the generation of microwaves to image the surface of the Earth, even in poor visibility or the hours of darkness. In partnership with William Kirk’s SurveyAR, and Brazilian radar developers Radaz, Central Alliance conducts SAR surveys all around the world with the RD350 Multiband SAR system aboard a DJI Matrice 600 Pro Drone.
The RD350 is the only combined C, L and P band UAS radar on the market, with the only system in the UK currently in use by Central Alliance. The simultaneous use of the multiple frequency bands, C and L allows the surveyor to define topography, and moreover investigate the near subsurface with the lower frequency P band.
Network Rail defined the target areas with an ecological reconnaissance visit, and final flight missions were designed and agreed with Central Alliance to investigate both areas for beaver burrows using a combination of linear and helical flight patterns 120m above ground.
In Rail Week 48 of the Financial Year 24/25, Applied Technologies’ lead UAS pilot Adrian Pawsey and Adrian’s colleague as the Spotter, made the journey to the Cairngorms and Ochil Hills to fulfil this mission, joined by SurveyAR Director William Kirk and Network Rail Project Manager and Ecologist James Morrison.
Ten Multiband SAR flights were completed over both sites: six helical missions and four linear missions.
Using the data acquired in the field, radar experts Radaz processed the raw field data into GeoTIFFs showing plain and cross polarized data for the C, L and P bands; CVV, LHH, LHV, PHH, LVV and LVH.
A convoluted neural network analysis was performed on the deeper penetrating P band data to discern the presence of, and moreover classify, any beaver burrows occupied, collapsed or partial, present on the site.
The analysis of Gleneagles shows there are currently up to a potential of seven actively inhabited beaver burrows, stretching down to depths of two metres.
As a research platform, the drone-based SAR platform continues to impress and is growing continuously with methodological improvements being implemented in the field, and advances in technological capability on the processing side.
Following the Network Rail Beaver project, SurveyAR and Central Alliance next look to Kintore, Aberdeenshire, where the team will investigate a site for badger setts, using a similar methodology presented above.
Key Project Details
Location: Gleneagles and Pitlochry, Scotland
Client: Network Rail
Sector: Rail
Services: Multiband SAR Drone Survey
