How the Cars of Tomorrow Will “See”: The Future of Lidar and Radar

We are in the middle of the most radical technological transformation ever seen in the history of the automotive industry. Not only are we powering through a wholesale shift from internal combustion power to electrification, but every new-generation car that hits dealerships is also that much better at essentially driving itself than those that came before.

Yes, we're well behind the curve toward true autonomous driving that many were predicting five or six years ago. But still, we've reached a point where roughly 70 percent of new cars sold offer some form of advanced driver assistance system, or ADAS, according to IDTechEx. Those systems are the subject of massive research and investment by every major auto manufacturer on the planet, with the suppliers for those companies working just as hard to keep us moving forward to a safer—and eventually driverless—future.

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While software development, especially neural networks and other aspects of machine learning, tend to get the biggest headlines, the evolving ADAS systems to come will require ever more comprehensive sensors to see the world around them. Integrated radar sensors, only found in high-end cars a few years ago, are now nearly omnipresent at every price point. Soon, they'll be supplemented by lidar sensing and other technologies, enabling more cars to see more things more often from even farther away.

What can we expect from these sensors in tomorrow's cars? We talked to some of the industry's biggest suppliers and an automaker leading in the field to find out.

More Sensors in More Places

It's always difficult to predict the future, but one trend is so obvious that it's easy to project that line forward: Tomorrow's cars will offer more sensors than today's, and not by a small margin.

Every supplier we spoke with echoed this trend. "The expansion is crazy," Bhavana Chakraborty said. She's the engineering director for driving systems at Bosch, which has been producing radar sensors for 20 years. The adoption of basic ADAS, she said, like automatic emergency braking and adaptive cruise, is exploding: "If you look at 2016 to 2028, it is going from 10 percent to 100 percent installation for these features. And radar is one of the key components for it."

Tier 1 supplier Magna recently shipped its 75 millionth radar sensor. "If you go back five, 10 years, it was more of a niche product for luxury vehicles," Steven Jenkins, Magna's vice president of product line, ASI, and technology strategy, said. "With Level 3 cars, you start to get into five radars, and you get into potentially a five-camera solution plus one forward-looking lidar."

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Volvo is an excellent example of this evolution. Volvo's current top-end XC90 luxury SUV has three radar sensors: one in the nose and two more at the rear, each pointing diagonally backward. The company's upcoming EX30, a small electric crossover SUV that starts under $35,000, raises the bar to five radar sensors.

The company's next large SUV, the electric EX90, has even more: five radar sensors plus eight cameras and, for the first time for Volvo, lidar. But Thomas Broberg, Volvo's senior technical adviser for safety, told us the intent isn't to use these sensors to shove even more information into the face of drivers.

"Our philosophy there is that we should support in such a way that it's not disturbing," Broberg said. "It should be there when you need it so that you don't even notice."

More sensors, in this case, means not only detecting more things but also being smarter about identifying real threats, filtering out false positives, and creating a safer, less distracting experience.

Next-Gen Radar

When it comes to the now-humble radar sensors, again, to predict the future, it's nice to look at the past. How have radar sensors improved since they first appeared on vehicles decades ago? "Size, resolution, accuracy, everything," Bosch's Chakraborty said.

The company's radar sensors have dropped from 600 grams to just 75 grams in weight. Meanwhile, their range has extended from 150 meters to 300, and their field of view has expanded from 6 degrees to 60. "It's almost like we used to look through a keyhole, and now we open the whole window," she said.

All these steps forward are happening while costs are decreasing, a huge reason why manufacturers can put so many radar sensors on a reasonably affordable car like the Volvo EX30. Those additional sensors are not only helping make for smarter driver assistance and eventually autonomy but also add more practical features.

Bosch's Chakraborty said the company is working on a rear-facing radar system that can detect the presence and size of trailers being towed and automatically extend the tow vehicle's blind-spot warnings to match.

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However, one area that might not need further improvement: range. "Range-wise, we've seen some significant improvements over the past five to 10years," Magna's Jenkins said. "The range is pretty optimal given the road scenarios we want to achieve today."

Radar fidelity, though, will continue to improve, with the most significant step forward coming from something called 4D, or imaging radar.

"Imaging radar is a really interesting thing," Jenkins said. "One of the fundamental problems with radar is objects that are close to each other, reflective surfaces." Imaging radar will allow for higher fidelity. "You can start to differentiate between bridges and fence posts."

Bosch is working on this technology, as well. "We are able to have separation of one degree," Chakraborty said. "So if you have a huge truck and a motorcycle, both driving very close to each other, you can still reliably separate them." She said a system like this could even detect and separately track a person falling from that motorcycle.

But despite these improvements, electrical consumption has not increased. "Power surprisingly has been the same; we're just able to do a lot more," Chakraborty said. As cars start to get more powerful with ECUs capable of processing ever more raw data, the sensors can potentially simplify their own processing, which could get individual sensor consumption down to as little as four watts per sensor—less than half the consumption of a household LED light bulb.

More advanced sensor logic will likely have an even more significant increase in efficiency, Jenkins said. "Keep adding additional sensors in the vehicle, and you just end up draining the battery," he said. But by being smarter about sensor use, for example perhaps only enabling the full suite of sensors when driving on a dense city street, power demands could be cut significantly.

Efficiency only becomes more important as we shift toward electric vehicles, which will be more power-sensitive than their internal combustion counterparts.

There's another place where low-power radar will come into play: within the cabin. Lower-frequency, 60GHz radar systems have been approved for use within the cabin, where they'll initially be used for things like occupant detection, ensuring that nobody is accidentally left inside a locked vehicle.

Volvo will be the first to deploy an internal radar system on a car with the EX90. "For the EX90, we're focused on no one left behind," Volvo's Broberg said. "We know that, for a fact, it's easy when you have a busy day that you forget, you're stressed, and we also know that the worst can sometimes happen. And of course, we want to try to avoid that."

But the potential is much higher. A big focus for Volvo, Broberg said, is not just avoiding accidents but preventing situations that could result in them. This involves better detecting when drivers aren't in an optimal state for driving, perhaps due to stress or intoxication. An internal radar system might help extend the company's existing driver monitoring sensors, better identifying things like slouching posture or other signs of reduced functionality.

This information might also help a next-gen airbag system fire more appropriately based on a person's position during the crash.

Next-Gen Lidar

Radar is a tried-and-true technology on the automotive front these days, with numerous suppliers offering sensors of varying sizes, costs, and capabilities, all hardened to survive the life of a vehicle. Lidar, on the other hand, is a newer technology from an automotive standpoint.

But that's changing. Early lidar applications for autonomy testing and development "were not considered what is called automotive-grade," Innoviz's chief business officer Elad Hofstetter said. Today, the company is developing sensors that, per Hofstetter, can survive 15 years of automotive exposure.

Innoviz is a global supplier of lidar technology to automakers including BMW, whose present focus is largely on extending the operational design domain, or ODD, of its sensors.

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This means future sensors that can see through weather conditions that flummoxed many earlier lidar sensors. This limitation is a key reason why autonomous test vehicles traditionally run for home when the forecast turns sour. "It's one thing in good weather conditions to have the lidar work nicely, but life is not always like this," Hofstetter said. "We'll have rain, we'll have snow, we'll have mud, and so on. You want to ensure that your lidar is available almost all the time as much as possible."

Innoviz isn't just improving its sensors to better see through conditions like this. It also seeks to identify areas of the sensor that are blocked by snow or mud or other muck, preventing potential false positive sensor readings.

Dirt and grime on sensors is an increasing problem and a topic of continued research. Additional washer nozzles are a straightforward solution, but technologies ActaJet's compressed air and even muck-resistant oleophobic coatings will play a part.

Still, there's a significant focus on reducing cost for Lidar, and increasing quality. Lidar, being much newer to the automotive world, is still seeing rapid improvements. Hofstetter said early lidar sensors, the giant units installed on prototype self-driving machines, often cost thousands of dollars.

"Obviously, you cannot put such a lidar on a consumer vehicle," he said. "Since then, a little bit like Moore's Law, [cost has] been reduced year over year, year over year significantly." Nobody we spoke to wanted to talk about current sensor pricing in detail, he said today's sensors are priced in the hundreds of dollars, and they'll only get cheaper.

And better. With each generation of its lidar sensors, Innoviz has seen costs drop by more than half while raising effective performance (resolution and field of view) significantly.

That cost reduction will lead to more sensors in more cars. Hofstetter said Innoviz expects to see as many as four or five lidar sensors embedded in future autonomous vehicles. "Evinteentually, you want a coverage of 360 [degrees] in some cases," he said, "[and] also redundancy because there are different occlusions and sometimes different aspects for performance."

That presents a new challenge: design integration.

Where radar sensors can often be hidden behind body panels and positioned low to the ground, lidar sensors need to see the world around them and, ideally, be positioned higher up. Hofstetter likened initial, roof-mounted lidar sensors to "a KFC bucket." Future lidars, he said, will be smaller, lighter, and even quieter, enabling them to be installed closer to or even within the passenger cabin. Automotive designers have "huge weight" in deciding sensor placement. "They don't design the vehicle around the lidar," Hofstetter said. "It goes the other direction."

And, just like we're seeing low-power radar sensors used in the cabin for occupant detection, Lidar systems will start pointing inwards as well. System's like Gentex's In-Cabin Monitoring System can detect people left inside the cabin and even monitor their health.

Better Sensing Without Sensors?

While sensors continue to improve, one of the more compelling shifts for in-vehicle sensing might not require any new sensors at all. Instead, this trend has more to do with increasing communication speed between cars. With vehicle-to-vehicle (V2V) communication becoming more commonplace and with the bandwidth of that connection increasing thanks to technologies like 5G LTE, cars can potentially start sending far more comprehensive information to each other.

That means one car could provide detailed sensor data for other vehicles still miles away, enabling them to "see" obstacles and issues, even trends in vehicle speed, well beyond the reach of even the most advanced future sensors. Magna's Jenkins calls these "virtual sensors."

"Sensors in two different vehicles in two different places that communicate with each other via the cloud," he said.

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After decades of promises, this aspect of V2V technology is finally becoming a reality. Chakraborty said Bosch has already captured over 2 billion kilometers of this sort of data, part of a system it calls Connected Map Services. Bosch has partnered with one major OEM to begin deployment in Europe soon.

Solutions like this could mean safer, smarter cars without the additional cost or burden of onboard sensors. It's a rare engineering win-win. More of these wins are sure to come as ADAS and the lidar and radar systems they need to work continue to develop, as well.