Researchers attain record radar measurement precision
17 September 2012
A joint research team in Germany has obtained record precision in radar distance measurements, achieving an accuracy of one micrometer in joint measurements taken earlier this summer.
Precise determination of distances is of increasing importance in fabrication technology, for instance, when actuating robots, producing micromechanical components, or controlling machine tools. Frequently, glass scales, inductive sensors, or laser measurement systems are used for distance measurements.
Glass scales are very precise and reach micrometer precision. However, they are too inflexible and expensive for daily use. Inductive sensors measuring distances with a coil, magnetic field, and movement work in a contact-free manner and, hence, without wear, but are limited in the measurement repetition rate.
Lasers also allow for a highly precise measurement, but are not suited for environments with dust, humidity, or strongly changing light conditions. Radar signals, by contrast, can penetrate dust and fog quite well. So far, radar systems have been used mainly for weather observation, air monitoring or distance measurement in vehicles.
Scientists from the Institut für Hochfrequenztechnik und Elektronik (IHE) of Karlsruhe Institute of Technology (KIT) and Ruhr-Universität Bochum (RUB) have now developed and successfully applied a radar system for distance measurements. In a joint test in July this year, they achieved a new record precision for radar distance measurements of one micrometer.
For measurement, the scientists use a frequency-modulated continuous wave (FMCW) radar, whose emitter is operated continuously during measurement. The RUB researchers developed the hardware, while the KIT scientists developed the algorithms.
The radar system, with a special measurement set-up, measures distances of up to several metres in free space to micrometer accuracy. Compared with laser systems, this system is not only cheaper, but can also measure absolute positions.
The radar system is now being optimised in several research projects, and it is hoped that its accuracy will be further improved.