solid state lidar

Cheaper lidar system aid mass adoption of driverless cars

Image credit: University of Colorado Boulder

US-based researchers have been developing a lidar system - a key component of driverless cars - which has no moving parts.

Light Detection And Ranging (lidar) systems enable vehicles to ‘see’ in real-time by mapping three-dimensional images. The systems use large, rotating mirrors which reflect laser beams from surrounding objects.

A University of Colorado-Boulder team has been working on a different way of steering these laser beams, called wavelength steering.

This technique involves pointing each wavelength of laser light to a unique angle. This allows for a lidar system which is far less bulky and expensive, and can be easily made smaller than current devices.

In addition, the new system has no moving parts and improves the resolution and scanning speed needed for a lidar system.

“We’re looking to ideally replace big, bulky, heavy lidar systems with just this flat, little chip,” said Nathan Dostart, lead author of the study.

His team developed a new way to carry out lidar scanning along two dimensions simultaneously, using a “rainbow” pattern to take 3D images. Since the beams are easily controlled by simply changing colours, multiple phased arrays can be controlled simultaneously to create a bigger aperture and a higher resolution image.

“We’ve figured out how to put this two-dimensional rainbow into a little teeny chip,” said Kelvin Wagner, co-author of the new study.

Lidar has been used for at least 50 years in satellites and aeroplanes to conduct atmospheric sensing and measure the depth of bodies of water and heights of terrain. While great strides have been made in the size of the systems, they remain the most expensive part of self-driving cars by far, costing as much as $70,000 (£56,000) each.

For broader adoption, lidar must become even cheaper, smaller, and simpler.

The researchers believe their new finding could play an important role in advancing silicon chip technology for use in lidar systems.

“Electrical communication is at its absolute limit. Optics has to come into play and that’s why all these big players are committed to making the silicon photonics technology industrially viable,” said Professor Miloš Popovic, co-author and electrical engineering expert at Boston University.

Autonomous vehicles are currently a $50bn (£40bn) industry, projected to be worth more than $500bn (£400bn) by 2026.

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