Ground-penetrating radar offers new sensor modality for vehicles

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Sensors are key components for autonomous vehicles as well as vehicles with advanced driver-assistance systems. As I commented in my November 2019,¹ the typical radar, lidar, and vision sensors may not be enough, and ground-penetrating radar offers an intriguing alternative.

WaveSense, founded in 2017, describes itself as the first company to offer self-driving vehicle navigation based on ground-penetrating radar at commercial scale. The company is the worldwide exclusive licensee of IP generated at MIT Lincoln Laboratory, where the technology was developed for military applications and deployed in Afghanistan in 2013. The technology allowed 9-ton military vehicles to stay on previously mapped routes despite unmarked lanes and poor visibility from sand and dust.

Tarik Bolat, cofounder and CEO, described how the technology works. “Rather than using satellites or looking around using lidar or a camera, we use something called ground-penetrating radar, which is radar that goes underneath the vehicle and maps the subsurface, typically 10 feet into the ground, getting reflections off things like changes in soil type, density, rocks, cavities, and utility infrastructure,” he said in a recent phone interview. GPR, he added, “…generates a very unique, very differentiated, very stable fingerprint that you can use to navigate…” after the mapping has taken place.

He said the need for reliable, precise positioning for autonomous cars, trucks, and robots as well as vehicles with ADAS is skyrocketing, with passenger vehicles increasingly featuring autonomous parking, active lane keeping, and other positioning capabilities in all sorts of conditions.

GPS, he added, can be unreliable and unstable. And with lidar- and camera-based approaches, you need three things to be true: you need a lot of roadside features, which may be lacking on an open highway; you need differentiation, which may be lacking in a parking garage with repetitive columns; and you need the mapped environment to be static over time, which may not be possible because of changes in foliage or inclement weather.

With ground-penetrating radar, “…looking into the ground, we are able to satisfy all those conditions,” he said, adding that the subsurface is very rich in features, highly differentiated like a fingerprint, and static over time (with some obvious exceptions). City environments in particular, he said, are highly dynamic, and it’s difficult to keep maps based on lidar and cameras from going stale. He said the company is doing a log of work in parking garages, where other sensors can have difficulty determining what level a vehicle is on.

WaveSense hasn’t set pricing yet for the technology, but Bolat put the BOM cost at less than $100 per vehicle. He said the ground-penetrating radar could knock out some of the lidar cost. The unit itself measures two feet by two feet by one inch and delivers a finished position. He said the trucking sector might want to retrofit existing vehicles, but the company’s primary targets are automakers’ future vehicle platforms. Pilots in conjunction with automakers are ongoing, he said.

REFERENCE

1. Nelson, Rick, “Three-way race to the future,” EE-Evaluation Engineering, November 2019, p. 2.