The threat of urban canyons to autonomous vehicles

Autonomous vehicles (AV) are at risk of signal black-out caused by “urban canyons” in cities across the world due to the continued growth of skyscrapers and urban infrastructure, warns UK-based AV software specialist, Oxbotica.

Urban canyons are formed when a street is densely populated by tall buildings on both sides. This can cause the GPS signal at ground level to be degraded or lost which has potential safety and operational implications for AV systems that rely heavily on satellite-based navigation.

Increase in tall buildings

The number of tall buildings (above 200m) has risen by 650 per cent in the last five years (according to the Council on Tall Buildings and Urban Habitat). And with this number set to increase again by up to 20 per cent in 2020, the frequency of urban canyons in cities is only set to grow, according to Oxbotica.

Even a standard three-storey building is enough to create signal disruption at ground level, it reports. And the problem is worse 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, the company reports.

However, canyons are not the only issue with GPS dependency. Sunspots formed during the sun’s 11-year magnetic field cycle cause marked changes in the solar wind. This impacts the upper atmosphere which can in turn interfere with GPS satellites. The solution is to use a mix of radars, cameras and lasers to navigate and localise rather than relying solely on GPS.

“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,” said Ben Upcroft, vice president of technology at Oxbotica.