Autonomous vehicles could face signal black-out caused by so-called ‘urban canyons’ in cities across the world due to the continued growth of skyscrapers and urban infrastructure, according to Oxbotica, an autonomous vehicle software developer.
‘Urban canyons’ are formed when a street is densely populated by tall buildings on both sides. This can reportedly cause the GPS signal at ground level to be degraded or lost, either through satellite signals being obscured, or through multipath effects: a phenomenon where radio waves bounce off surroundings and form multiple signal paths.
According to the company, interruption of GPS signals, through connection drops or multipath degradation, has potential safety and operational implications for autonomous vehicle systems that rely on satellite-based navigation.
A standard three-storey building is said to be enough to create signal disruption at ground level. And the problem reportedly worsens at higher latitudes where satellites tend to be lower in the sky.
If no suitable fallbacks are in place, this can affect autonomous vehicles in these environments, including mass transit shuttles, buses, city delivery vehicles and cars, said Oxbotica.
However, ‘urban canyons’ are reportedly not the only issue with GPS dependency. Sunspots formed during the sun’s 11-year magnetic field cycle are said to cause marked changes in the solar wind, which impacts the upper atmosphere and in turn interferes with GPS satellites.
Oxbotica said it believes the solution is to use a mix of radars, cameras and lasers to navigate and localise rather than relying solely on GPS.
Paul Newman, CTO and founder at Oxbotica, said: “My first job was in the maritime positioning industry where we were providing alternatives to GPS positioning systems for ships and oil rigs in the Gulf Of Mexico two sun-cycles ago, now I’m in conversations about the same problem hitting autonomous vehicles on our roads, and in our mines– on top of being in any number of canyons.
“While it is harder to figure out your location using vehicle-mounted sensors rather than being told it by GPS, the rewards are many.
“Entirely new commercial opportunities open up – working underground is no different to a high street, an autonomous shuttle is no different to a haulage truck in a mine.
“This is a powerful concept and underpins our Universal Autonomy software platform.”
Oxbotica’s autonomy technology is designed to be able to work independently of external infrastructure, allowing continuous localisation and control of its vehicles without a GPS signal.
The company’s localisation system uses a mixture of radar, laser and vision sensing to deliver autonomous operation in a range of settings, on different vehicle platforms and under varying conditions.
The technology has operated in a range of environments without access to GPS, for example in mines and quarries, inside warehouses, and in ‘urban canyons’ across Europe, Asia and America.
It uses the same software to run autonomous vehicles, in different environments, without needing to change lines of code.
Ben Upcroft, vice president of technology at Oxbotica, said: “There are so many ‘urban canyons’ and GPS blind spots across our towns, cities and countryside, that we can’t rely on GPS for accurate navigation.
“While this may pose a problem for some autonomous vehicles, our software is designed to mitigate this and is able to work independently of a GPS signal, helping us to bring autonomy to any vehicle in any environment.”
Read more from CiTTi
https://www.cittimagazine.co.uk/the-road-to-real-world-deployment-of-autonomous-vehicles/
