The European Commission co-financed the establishment and implementation of the “Slovenia Wide Area Multilateration System - SLOWAM” by Slovenia Control

7/27/2020

Ljubljana, Slovenia – The European Commission supported a 2-yea​​r project of the “Slovenia Wide Area Multilateration System” (SLOWAM), implemented by the company Slovenia Control (Kontrola zračnega prometa Slovenije, d.o.o. or KZPS, d.o.o.). The European Commission financed the project in the framework of the Connecting Europe Facility (CEF) in the amount of EUR 772,500. The project, which contributes to the Single European Sky (SES) with a focus on the introduction of new technologies and best practices, was monitored by the Innovation and Networks Executive Agency (INEA).


The SLOWAM project was related to the purchase and implementation of the Wide Area Multilateration system intended for air traffic operation and surveillance.

“The project contributes to the better detection of aircraft, (particularly) in the eastern part of Slovenia, and is an alternative to the purchase of at least two radars, which would mean significantly higher costs. Slovenia Control thus follows the orientations of the European strategy of the replacement of secondary surveillance radars by selecting new, better and more cost-effective solutions,” says the director of Slovenia Control Dr. Franc Željko Županič.

The goal of the project was to set up technology that is used for determining aircraft position. The radar transponder on the aircraft transmits a signal that is received by the receiver station. These are positioned at 19 various locations and thus at different distances from the aircraft. As a consequence, the transponder’s signal covers different distances to the receiver stations, which receive the signal at different times. Based on the time differences (Time Difference of Arrival – TDOA), the central processing station calculates the aircraft’s position.

The system can calculate the 2D or 3D aircraft position. The signal from at least 4 receiver stations is required for the calculation of the 3D position. The system itself is positioned so that there is no degradation in the event of the failure of one receiver station (N-1). A location must therefore be covered by at least four receiver stations.

The system can be passive or active. If an aircraft transponder is interrogated by the secondary radars frequently enough, the system only consists of the receiver stations that receive the responses. If necessary, transmitters are added to ensure the adequate frequency of transponder interrogation.

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The maximum precision in determining the position can be achieved if the aircraft is within the area outlined by the receiver stations. The position of the green aircraft (right figure) can, for example, be determined with greater precision than the position of the red aircraft.

 

The future use of the new contemporary multilateration system will further improve the reliability and robustness of determining the position of the aircraft in the air. Furthermore, this technology is completely sustainable from an ecological point of view.

 

For more information, please contact:

Katja Tratnik, Zgornji Brnik 130n, 4210 Brnik - aerodrom, Slovenia, Tel.: +386 4 20 40 235,

Mobile: +386 51 272 973, E-mail: katja.tratnik@sloveniacontrol.si



Editor's note:

Slovenia Control provides quality and efficient control and operation of air traffic in the Slovenian airspace, issues aircraft information and introduces, maintains and upgrades the systems and devices for the operation and control of air traffic. The company has established good relationships with the neighbouring countries and its goal is to contribute to achieving the goals of the European Commission regarding the establishment of Functional Airspace Blocks (FABs) in Europe.

Responsibility

The author bears full responsibility for the contents of the article. The European Commission shall not be responsible for any use of the information contained in this article.