From Gizmag. Autolanding is easy with multicopters using ultrasound, but hard with planes, since ultrasound is too noisy. Maybe radar would be better?
Excerpt from the article:
Research based in Frankfurt, Germany, and funded by the European Union, has resulted in a new low-cost, fingernail-sized radar chip package that could be implemented in a variety of areas, including the automotive industry, robotics and smartphones.
The chip was developed under the “Silicon-based ultra-compact cost-efficient system design for mm-wave sensors” (or Success) consortium, and is believed to be the smallest complete silicon-based system-on-chip (SoC) device for radar able to operate at frequencies beyond 100 GHz.
“As far as I know, this is the smallest complete radar system in the world,” said Professor Christoph Scheytt, coordinator of the project on behalf of IHP Microelectronics in Frankfurt, Germany. “There are other chips working at frequencies beyond 100 GHz addressing radar sensing, but this is the highest level of integration that has ever been achieved in silicon.”
The chip package measures 8 x 8 mm (0.3 x 0.3 inches), operates at 120 GHz, and can calculate the distance of an object up to around 3 meters (10 feet) away, to an accuracy of within 1 mm. It can also detect moving objects, and their velocity, by using the Doppler effect.