Saving lives at sea from space by mapping uncharted lifeboat routes

A pioneering project is helping lifeboats safely navigate the shifting waters of the Solway Firth on rescue missions by harnessing data from satellites.

The estuary is regarded as one of the U.K.’s most treacherous stretches of coastline as it is exposed to some of the fastest tidal movements and ranges in Europe. Large areas of mudflats surround the estuaries of the River Nith and River Annan, with many areas vulnerable to quicksand.

Lifeboats must frequently navigate the areas at high speed, but even state-of-the-art marine navigation maps leave areas blank and uncharted, increasing the risk of the rescue services themselves becoming casualties.

Satellite imagery

The University of Strathclyde was approached by Nith Inshore Rescue—one of the U.K.’s busiest independent lifeboat stations—with an idea to use satellite imagery to identify navigational channels through uncharted waters. The volunteer lifeboat is based in Glencaple, South-West Scotland and serves the Upper Solway and Dumfries area.

Under the “Safe Passage” project, the research team are now using the estuary as a trial site to support safe navigation of the flats.

Researchers from the University’s Applied Space Technology Laboratory are investigating the use of synthetic aperture radar (SAR) data from satellites to provide regular, accurate mapping of moving channels in the coastal region.

Radar signals

Through the use of polarized radar signals, the data can differentiate between sand and water, and even works under nocturnal or cloudy conditions, allowing the lifeboat to find a consistent minimum depth along the route.

The crew had to previously manually conduct depth soundings, but during bad weather and strong tidal periods these passageways shift rapidly, rendering the measured route futile. Inaccurate information can mean the lifeboat has to switch course mid-rescue, slowing down response and even potentially grounding it.

Principal investigator Professor Malcolm Macdonald, chair of applied space technology at Strathclyde, said, “The work investigates the alternatives to provide regular mapping of the intertidal zone, enabling these teams to reach casualties without becoming casualties themselves. They need to get to the scene as safely and quickly as possible.

“The crews were manually depth gauging the flats every fortnight but they can change on an almost daily basis. A key challenge is that we’re trying to provide an operational service to a volunteer crew, so we can’t just buy expensive, state-of-the art data.

“Optical satellite data—similar to how your phone works—works well in other parts of the world, but on the west coast of Scotland, you get predominantly pictures of clouds. Radar data penetrates the cloud but can be difficult to interpret, and so we started looking at how we could use that data.”

Coastal flooding

The volunteers now receive updated charts of satellite imagery generated waypoints, with the routes used in real life rescues, including a successful call out on the Cumbrian coast for two casualties trapped in a car due to coastal flooding.

The route charts are also backed up by the crew’s own skills and local knowledge, but climate change is making this increasingly difficult.

The team is now working with ESA to improve the charting and believe the system could make the 13 million hectares of tidal flats across the world more accessible. It’s also hoped to eventually commercialize the data feed service, with a slice of the profits funding the independent rescue service.

Safe navigation

Crew Member Gwilym Gibbons, who is also founder of project partner Creative Help, said, “Working with the team is the key enabler of this innovative way to aid safe marine navigation for search and rescue. To see and test the results of the work in a real environment as an additional aid has already proved the huge potential this could have across the world.

“Our ambition is for Safe Passage to become a commercial navigation data feed service for a range of marine navigation uses, with a proportion of revenues generated going to support the vital work of our wholly volunteer lifeboat services.

“It’s literally saving lives at sea from space.”