Quanergy has announced its latest updates of its solid-state lidar, which utilize optical phased arrays (OPA) in CMOS-compatible silicon photonic integrated circuits (PIC). Quanergy has demonstrated 100-meter range (about 110 yards), and it is aiming to achieve a 200m range by the end of the year.
Lidar, an acronym for light detection and ranging, is a sensing technique that, by transmitting low-power laser pulses, measures the time taken by the laser to complete the round trip between the sensor and a target. The aggregated data thus produced is used to generate a 3D image of the point cloud, providing spatial location and depth information to identify, classify and track moving objects. Quanergy Systems is providing lidar sensors and smart sensing solutions for real-time 3D object detection, tracking, and classification, and employs both scanning and solid-state technologies in its products.
The auto industry has set very challenging targets for lidar manufacturers. For instance, they need to detect a black tire from 150 meters away to allow a self-driving car to avoid it. Moreover, the lidar sensors need be highly immune to vibration and they need to be manufactured at very low cost to make them affordable for everyday passenger vehicles.
The OPA technology behind its solid-state product has been regarded by many as the “holy grail” of lidar technologies since it can provide the performance, manufacturability, immunity to vibration and cost targets required by the transportation industry.
OPA is the optical analog of phased array radar. A phased array has multiple stationary antenna elements that are fed equal-intensity coherent signals and use variable phase or time-delay control at each element to generate an arbitrary far-field radiation pattern and sweep it in space. Phased array technology had successfully demonstrated low-cost large-scale commercial deployment in automotive radar, in large part by taking radar a revolutionary step from mechanical to solid state.
In an interview with EE Times, Tianyue Yu, chief development officer & co-founder at Quanergy, highlighted the features of OPA-LiDAR technology as a 3D world-perception device. “Quanergy’s latest OPA technology advancement has demonstrated relevant performance levels for mobility applications. 100m range has been achieved at the current technology node. New emitter and detector chip iteration arriving in 2021 will enable 150-plus meters detection range, all for 10 percent reflectivity target under bright sunlight conditions” said Yu.
Since it has no moving parts, OPA-based solid-state lidar is more durable and reliable than mechanical lidar. Moreover, it also allows for fast scanning, small size, and lower price. “Our view is that at the current stage, mechanical Lidar, is the workhorse of today’s deployments. But in the end, the solid-state lidar platform is the linchpin for the ultimate lidar democratization, because of its low cost and high reliability,” she added.
Lidar measurement principle
The principle on which lidar is based is the measurement of time of flight (ToF), which is the time required by an object, particle, or electromagnetic wave to travel a certain distance through a medium. ToF differs from FMCW (frequency modulated continuous wave) technique, which instead measures distance based on the phase shift undergone by the reflected signal with respect to the transmitted signal (Doppler effect). Although FMCW lidars have been around for a long time (the first research activities started a few years after the discovery of the laser), ToF lidars offer superior performance thanks to very fast laser pulse transmission (several million pulses per second), agile scanning, higher return amplitude and the ability to apply high-density regions of interest (ROI).
The detection, acquisition, classification and tracking of long-range objects are strongly dependent on the frequency of the transmitted pulses: a higher density of laser pulses (distributed in space and/or time) provides more information that allows faster detection times and better noise filtering. Advantages of lidar include high accuracy and resolution, 3D object detection, high performance in harsh ambient and lighting conditions, and long sensing distance.
Comparing to camera-based optical systems, lidar is capable of operating in harsh environmental and light conditions, including heavy rain or deep night. In addition, lidar sensors offer high accuracy and excellent angular resolution, making this technology suitable for several applications such as: mapping, smart cities, smart spaces, security, industrial automation, autonomous vehicles, and transportation.
Scanning lidars use mechanical rotation to spin the sensor, allowing 360° detection. This technology provides a high scanning rate and is very safe, even using higher power lasers, as the light is not transmitted in one direction only.
Quanergy’s solid-state lidar utilizes optical phased arrays (OPA) in CMOS-compatible silicon photonic integrated circuits (PIC). “Optical phased array technology enables electronic beamforming and steering, which is achieved by interference among light beams emitted from a large number of phase-controlled optical antenna elements. Once emitted, that directional beam hits objects in the beams’ path, and then reflects back. The reflected beam is received and processed to measure the time of flight, enabling real-time 3d-mapping, object detection, classification and tracking. A number of lidar sensors can be integrated into the design of any vehicle providing a 360-degree surrounding coverage as needed,” said Yu.
As shown in Figure 1, with this technology, laser beams are steered, sweeping the view angle of the sensor with no moving parts. Laser beams can be steered and generate an arbitrary far-field radiation pattern by controlling the phase of each transmitting module composing the antenna array.
Quanergy, renowned for its OPA-based lidar, offers a product portfolio including hardware sensors and 3D perception software. Quanergy’s sensors and AI-based smart perception software technologies can be combined to create sophisticated solutions for industries such as smart city, smart space, security, and industrial automation.
The S Series includes 100% solid-state lidar sensors, based on OPA technology. Featuring electronic beam steering and no moving parts, Yu highlighted as these sensors achieve excellent levels of robustness and reliability. Quanergy’s OPA-based S-series sensors are immune to vibration, provide more than 100,000 hours of mean time between failure (MTBF). In addition, the affordable, scalable CMOS silicon process enables cost-effectiveness at mass production.
Applications of OPA-based LiDAR
Quanergy’s 3D Flow Management platform is powered by artificial intelligence (AI) algorithms, providing a modular, scalable, and advanced perception solution to enable real-time analysis for people counting, object detection, classification, tracking, and more. The Flow Management platform includes both M series mechanical sensors with Qortex DTC (detect, track, classify) software and S3-2 solid-state sensors with Qortex People Counter solution. This combined hardware and software solution is suitable for a wide range of applications in retail, airports, public venues, commercial and government buildings, and industrial facilities.
The Qortex People Counter solution delivers over 98% accuracy from pitch dark or indoor to very bright lighting conditions in full sunlight. As an integral part of Quanergy’s Flow Management platform, it is suited for outdoor smart space applications.
Besides flow management, other relevant applications of lidar OPA-based solutions include the industrial (port automation, measurement, warehouse automation, unmanned ground vehicle and autonomous mobile robot) and the transportation (ADAS, robo-taxi, autonomous valet parking and autonomous driving) sectors (figure 2).
For instance, the high degree of immunity to vibration is critically important in unmanned ground vehicles (UGV) applications such as mining, agriculture and constructions, and autonomous mobile robots. Figure 3 shows an automotive LiDAR application, where the device provides a 3D mapping for object detection, classification, and tracking. Multiple sensors can be integrated into the vehicle, providing a 360° field of view.