Radar scanner with all-round view
Researchers from Fraunhofer Institute for Applied Solid-State Physics (Freiburg, Germany) have developed a compact, modular radar scanner that is superior to optical sensors. Since it can penetrate smoke, dust and fog and does not generate misleading reflected signals on glass or plastic surfaces, it is ideal for deployment in environments with high safety requirements such as those where humans and robots interact directly. The radar sensors utilizes millimeter waves reflected by relevant objects such as persons. Since the beam is rotating by 360 degrees, it can monitor the environment completely.
Transmitted and received signals are processed by means of numerical algorithms. The results of these computations enable the circuitry to determine position, direction and speed of the objects scanned. If multiple radar sensors are used it is even possible to detect and determine the movement of the objects. According to Fraunhofer IAF, the radar does not focus on a single point but transmits the waves in the shape of a lobe. In contrast to conventional laser scanners typically used in such environments, the radar beam is reflected even in situations where optical visibility obstructions exist. While laser scanners only detects objects and their positions correctly if there is a direct line of sight, the radar scanner can “see” humans even if they are obscured by obstacles. And while existing millimeter wave radar systems based on waveguides tend to be clumsy, heavy and large, the IAF radar scanner is shaped as a cylinder with a diameter of just 20 cm and a height of 70 cm.
The scanner’s pedestal accommodates the RF module implemented with indium gallium arsenide semiconductors. “Today’s millimeter wave systems are dominated by waveguides, which are extremely expensive to produce”, says Christian Zech from Fraunhofer IAF. “Through a cost-effective design technology, we were able to replace the waveguide by a PCB the size of a cigarette box.”
The entire system includes a signal processing unit, an antenna and a dielectric, non-conductive lens. Above the RF unit, a rotating mirror is mounted at am angle of 45 degrees that deflects the millimeter waves and distributes them in a 360-degree angle. The dielectric antenna makes in possible to freely adjust the aperture angle, enabling the system to acquire small objects (size of centimeters) in the proximity of the system as well as large objects in the distance. The transmission range depends on the application and can amount to several hundred meters. Equipped with an Ethernet interface, the scanner suits Industry 4.0 environments.
The scanner will be showcased at the Hannover Fair (April 25 through 29, Stand C16/C22) and at the Sensor + Test trade fair (Nuremberg, May 10 through May 12, hall 5, stand 5-248).
More information: https://www.iaf.fraunhofer.de/en/contact.html
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