[PTB/if] Researchers from the Physikalisch-Technische Bundesanstalt (PTB), together with FCS Flight Calibration Services GmbH from Braunschweig, have developed a measuring system which, hanging from a helicopter, detects the electric field strength as well as the signal contents of air-traffic control navigation systems with unprecedented accuracy. They had hardly developed this system when a future potential application field of an extended hovering facility was found: the evaluation of recorded measurement data could be used already in the planning phase of wind farms to find out to what extent the planned wind farms would influence the operation of neighbouring radar facilities used for air-traffic control, aerial defence or meteorological observations. A miniaturized - and still strongly simplified - version of the measuring arrangement has already made its first test flights on an octocopter.
About the technology:
The core piece of this technology is a jointly developed antenna and receiver system. In its previous design, it hangs down from a helicopter and can measure the electromagnetic field strength at any random location in space and save the measured data as well as the exact location (GPS supported by EGNOS) with a very high sampling rate in real time. Successful tests have already demonstrated that this system is capable of measuring the electromagnetic far field which is necessary for a flawless signal transmission (e.g. between an instrument landing system and an aircraft) as precisely as required by the International Civil Aviation Organization (ICAO). The measurement is traceable to the International System of Units (SI) - i.e. the highest possible standard - which ensures its comparability. No one in Europe had ever achieved this before.
Thorsten Schrader (Head of PTB's "High Frequency and Electromagnetic Fields" Department) and his research colleagues and partners have now miniaturized this antenna system to fit it onto an octocopter (i.e. a miniaturized helicopter approx. 80 cm wide and equipped with 8 rotors). On such aerial vehicles, it might soon be possible to use the sensor at places where wind farms already exist or where they are planned in order to acquire data with regard to the field strength and to modified signal contents at any selected coordinates over any random periods. The researchers intend to use it in a first step to metrologically detect the real-time dynamic change in the electromagnetic wave propagation caused by wind farms, to analyze it and feed it into a (preferably) simple model of the electromagnetic data transmission channel.
The innovative approach provided by this project (WERAN - German acronym for "Interaction between wind farms and radar/navigation") consists in dividing the complex estimation of the disturbances caused to radars by wind farms into metrologically detectable intermediate steps and in comparing only compatible quantities from numerical simulations and measurements with each other. The project is funded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). PTB's research partners are the enterprises FCS and "steep" as well as the Leibniz Universität Hannover.
Dr. Thorsten Schrader, PTB Department 2.2 High Frequency and Magnetic Fields,
Phone: +49 (0)531 592-2200,