Radar has traditionally been awesome at “seeing” objects through rain, fog, and snow, but even in the sunshine the “image” it can generate tends to be way fuzzier than what the best lidar sensors can show. And as more cars are equipped with radar, the chance of cross-talk and mixed radar signals increases. Uhnder 4D digital-imaging radar promises to solve both these problems.
Digital Versus Analog Radar
The traditional analog radar like old smokey used to use to hand out tickets operates by sending out radio waves, then measuring the reflected signal. If there’s a difference in velocity between the radar unit and the object, there will be a Doppler shift in the reflected wave. Digital radar uses a similar radio signal, but each transmitter sends out a 77-GHz signal with a unique digital code modulated on it that allows the receiver to distinguish each individual signal from among any other 77-GHz waves bouncing around the area. This technique, known as digital code modulation, allows the system to sense instantaneous position as well as velocity.
16x Resolution
Typical integrated analog radar chip solutions pair three transmitters with four receivers, but Uhnder’s 4D digital-imaging radar chip features 12 transmitters and 16 receivers for 192 virtual radar channels, each capable of determining the speed and distance of an object in the distance. That vastly richer point cloud results in images with 16 times the resolution afforded by a standard analog radar unit.
24x More Power on Target
Uhnder says its chip consumes 7-13 watts, which it claims is roughly half the power (and cost) of a competitive setup using four chips to achieve similar results. Uhnder is only providing the sensor for automotive ADAS functions, but it expects suppliers like Magna (the first production contract) will program the chip to scan an entire scene, identify local areas of interest, and then interrogate those areas with even greater power intensity.
30x Better Contrast
Combine the improvement in resolution and the added power on target, and Uhnder claims its 4D digital-imaging radar can deliver 30 times the resolution of traditional analog radar. The resolution is said to be similar to that of lidar but at lower cost. That contrast improvement really pays off in distinguishing “soft” targets like pedestrians, bikers, and other vulnerable road users. According to the Automotive Safety Council, fatalities of these vulnerable folks now account for 20 percent of American roadway deaths (and way more in developing countries). And today’s pedestrian automatic emergency braking systems (which typically rely on cameras and/or traditional analog radar) are woefully incapable of distinguishing such targets after dark or in poor weather. Testing and rating of P-AEB systems is currently conducted in daylight. We expect 4D digital-imaging radar systems will proliferate like kudzu the minute NHTSA/IIHS start conducting safety testing at night.
Range and Limitations
The performance of camera and lidar systems is dependent on having a clear and clean lens. For high-quality results, a heating and/or cleaning system is required to keep these lenses free of snow, ice, and debris. Digital imaging radar systems like Uhnder’s don’t
have lenses, and thus present a high-resolution imaging solution for the harshest weather conditions when lidar and camera lenses could be partially blocked or covered. A Grand Cherokee we sampled was outfitted with five Uhnder radar units: one mounted front and center lensed for 300 meters (984 ft) and four corner units optimized for 80 meters (262 feet), and it operated without issue during our snowy test drive.
Fisker Ocean First to Go Uhnder
Production units began rolling off the line in April 2022, with Magna integrating them into an advanced driver assist system it sells as ICON Digital Radar and which is making its debut on vehicles this year, including the Fisker Ocean. Oh, and about the name: The company wanted to use a play on the saying “under the radar,” but that name was taken, so the vaguely German-looking and -sounding Uhnder was chosen.
Keyword: 4D Digital-Imaging Radar Is Coming to Cars—But What Is It?