Reliably measure long distances with LIDAR

Fully autonomous driving is still regarded as an important technology of the future, but its widespread use has been delayed. One reason for this is the extremely high reliability of the monitoring sensors required. In order to monitor the traffic area in front of vehicles, radar sensors and stereo cameras are usually used in conventional cars, but their lateral resolution and range are not sufficient for autonomous driving.

State of the art

For this reason, the lidar method (light detection and ranging), which is based on analyzing the reflection of laser signals, has been increasingly used in recent years. However, the currently leading technology principle with rotating prisms is expensive due to the storage technology. Alternative concepts with micromirrors have problems with large distances, as the receiving aperture for the backscattered light is too small. Increasing the laser transmission power is also difficult, as the safety of the human eye must not be jeopardized.

Technology

If the laser strength is to remain within the safe range, the receiving optics can be enlarged to increase the range. However, this entails an increase in the detector area. This in turn means higher costs for the detection unit. Researchers at the Institute of Information Processing Technology (ITIV) at KIT have succeeded in breaking this link. Instead of one large lens, their new technology principle uses several lens grids that can be shifted against each other in the micrometer range using a piezo actuator. These lens grids can be enlarged without increasing the detector area.

Advantages

The displacement vector can be changed so that the system can be adjusted to receive beams at specific angles. These receiving beams can then be focused precisely onto a cost-efficient detector with a small surface area. The lens grid is an inexpensive plastic injection-molded component. In combination with piezo-electric actuators, a very light but rigid system can be realized that is insensitive to vibrations and reliably measures even large distances.

Options for companies

Companies are using this technology to achieve a long-range, safe lidar system – without increasing the laser power or the receiver chip. It could be the decisive step towards finally making autonomous driving systems ready for series production. KIT is looking for partners to use the system.