Sensor solutions provider HENSOLDT has demonstrated the capability of passive radar for air traffic control (ATC), during a comprehensive measurement campaign using Twinvis, a passive radar system developed by HENSOLDT.

A passive radar sensor cluster was installed at four sites in southern Germany for the tests, which tracked air traffic above the region in real time. The measurements showed that passive radar systems can track aircraft with sufficient precision to be used for air traffic control. The sensors were positioned in Nuremberg, Roth, Erding and Ulm, while the data was processed centrally at HENSOLDT’s Ulm site.

Working only as receivers, which do not transmit any radiation, passive radar systems detect aircraft by analyzing signals from other sources that are reflected by the aircraft.

In civil applications, passive radar makes cost-effective ATC possible, without additional emissions or new spectrum, which is in short supply. In military applications, the system enables wide-area surveillance using networked receivers, offering the advantage that passive radar systems cannot be located by an enemy and are very hard to jam. No agreement is required with public authorities, as there is no transmitted radiation, which allows the system to be quickly deployed in new locations — also in urban areas. This results in another advantage of the new technology: the system can be used in places where coverage was previously inadequate, for example, in mountainous regions.

HENSOLDT's Twinvis system provides a comprehensive view of the airspace, obtained by simultaneously analyzing a large number of frequency bands: up to 16 FM transmitters (analog radio), with five frequencies used by DAB and DAB+ transmitters (digital radio), and DVB-T and DVB-T2 (digital terrestrial television). A new generation of software improves the range and detection precision.

Twinvis has shown what it can do in several demonstrations to military customers and air traffic control organizations. Two Twinvis demonstrators have already been delivered to potential customers in Europe.