While most autonomous sensor companies focus on scanning the car’s surroundings, Boston-based startup WaveSense thinks scanning below the car is just as important. The company is developing ground-penetrating radar (GPR) for autonomous cars to keep them in their respective lanes, especially during difficult weather conditions where other sensors would fail.
For subsurface sensing, GPR is one of the most versatile and prolific sensing modalities today. Although it isn’t a new technology, as it is already used in other areas such as geoscience, and various engineering applications, WaveSense certainly invented a new application for it.
By sending a pulse of electromagnetic radiation into the ground and measuring reflections that originate from scattering points – such as pipes, roots, and rocks in the surrounding “dirt”, but most importantly, soil layers and variations in moisture content – below the surface, WaveSense’s Localizing GPR (LGPR) is capable of creating a 3D map of the subsurface environment. According to WaveSense, “the premise of GPR localization is that these subsurface features are sufficiently unique and static to permit their use as identifiers of the precise location at which their reflections were collected.”
After developing a map of the environment below the road, WaveSense collects the GPR data of subterranean “objects,” along with GPS tags, to form the initial database of subsurface features. This subsurface map is then used as a reference data-set that helps estimate vehicle location on subsequent visits. To keep track of the vehicle, data is periodically fetched from the database for matching, and an algorithm narrows the search for the maximum correlation within the vehicle’s five-dimensional space (easting, northing, height, roll, and heading).
In 2013, WaveSense applied this technology in Afghanistan to enable “precise navigation of nine-ton military vehicles, despite unmarked lanes and poor visibility from sand and dust.” Fast forward 5 years, the company decides to join the fast-evolving automotive industry.
Since camera, radar, and lidar-equipped vehicles rely on road markings and prior maps for localization to stay in their lanes, severe-weather conditions can cause various issues in the process. At 60mph, WaveSense GPR technology achieves in-lane accuracy of 4cm not only on a sunny day, but also during low-light, snowy, foggy, rainy and dusty conditions, resulting in a safer and more reliable vehicle. However, WaveSense points out its technology isn’t a replacement for current solutions, but a complement.
WaveSense is currently running pilots and is open to applications through a pilot contact form available online, for those interested in participating.