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Wind farms and radar

Especially interesting for
  • air-traffic control, meteorology, armed forces
  • operators of wind farms
  • regulatory authorities

A new measuring system can, hanging from a helicopter, detect the electric field strength as well as the signal contents of air-traffic control and terrestrial navigation systems with unprecedented accuracy. As an extended measuring device, it will be able to acquire measurement data which can be used already in the planning phase of wind farms to find out to what extent the planned wind farms would influence the measured data and the subsequent signal processing of neighbouring radar facilities used for air-traffic control, aerial defence or meteorological observations.

In connection with the “Energiewende” (energy transition), an increasing number of wind farms are being built. However, the radar waves that are scattered up by their rotor blades can considerably interfere with the radar monitoring activities of meteorologists, air-traffic control and the armed forces. The simulation of the wave propagation, which is usually relied upon in these fields, requires numerous assumptions which could to date not be verified by measurements. Hence, interactions with wind farms cannot be assessed with sufficient reliability. The new measuring system developed by PTB and FCS Flight Calibration Services GmbH can provide the underlying data for simulation models and, thus, help experts establish more reliable predictions for the authorities issuing the authorizations.

The innovative approach provided by this project (WERAN – German acronym for “Interaction between wind farms and radar/navigation”) consists in dividing the complex assessment 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, Building and Nuclear Safety (BMU). PTB's research partners are the enterprises FCS and steep GmbH as well as the Leibniz Universität Hannover.

The measuring system consists of a reference antenna and a receiving facility. In the design used to date, it hangs down from a helicopter and can measure the electromagnetic field strength at any random location in space and synchronously save the measured data as well as the exact position with a very high sampling rate. Successful tests have already demonstrated that this system measures 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). These validation measurements are traceable to the International System of Units (SI), which ensures its comparability.

As the latest development, the measuring system was miniaturized and mounted onto an octocopter of approx. 80 cm in width. On such aerial vehicles, the system can be used 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 longer periods.


Thorsten Schrader
Department 2.2 High Frequency and Electromagnetic Fields
Phone: +49 (0)531 592-2200
Opens window for sending emailthorsten.schrader(at)ptb.de

Scientific publication

J. Bredemeyer, T. Schrader, T. Kleine- Ostmann, H. Garbe: Quasi-stationary signal-in-space measurements using traceable antennas. Proceedings of 17th International Flight Inspection Symposium IFIS (2012)