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ILA 2018: Just Listening …

Passive radar showcased at ILA Air Show in Berlin

Hensoldt unveils its TwInvis passive radar system (twin + invisible, as neither TwInvis itself nor the targets to be detected emit any signals on their own, which means that they are invisible) in live operation during this year’s ILA. The TwInvis system, which can be integrated into an all-terrain vehicle or a van, does not emit its own signals to monitor air traffic, but simply passively analyses the echoes of signals from radio or TV stations. To this end, it detects electromagnetic disturbances in the FM (Frequency Modulation) radio broadcast band of 87.5MHz to 108MHz, the Digital Audio Broadcasting (DAB) frequency band of 174.92MHz to 239.2MHz and the Digital Video Broadcasting Terrestrial (DVT-B) waveband also located in the 300MHz to three gigahertz ultra high frequency waveband.

“Our newly developed, highly sensitive digital receivers now make it possible for a single TwInvis system to monitor up to 200 aircraft in 3D within a radius of 250 kilometres. This was unthinkable even just a few years ago,” said Hensoldt CEO Thomas Müller. “This will open up completely new options for application in such fields as air defence, the protection of large events or air traffic control.”

Working as mere receivers, passive radar systems detect aircraft by analysing the signals that they reflect from existing third-party emissions. “TwInvis excels with a very precise picture of the airspace covered, which is obtained by simultaneously analysing a large number of frequency bands. For example, up to 16 FM transmitters (analogue radio) plus five frequencies used by several DAB and DAB+ transmitters (digital radio) as well as DVB-T and DVB-T2 (digital, terrestrial television) can be simultaneously analysed for the first time,” the company states. Furthermore, Hensoldt’s new generation of software will provide great performance in terms of range and precision of detection.

In civil applications, passive radar systems can act as a cost-effective supplement to conventional radar-based air traffic but without any additional emissions. In military applications, the system enables wide-area surveillance using networked receivers, while offering the advantage that passive radar systems cannot be located by the enemy and are very hard to jam, although they do of course depend on the availability of local FM, DAB and/or DVTB emissions being present. Moreover, no agreement is required with any other public authority, as there is no radiation, which allows the system to be quickly ready for deployment in new locations and to also be used in urban areas. This results in another advantage of the new technology: the system can be used in places where coverage was previously inadequate, in particular for example, in mountainous regions. HENSOLDT officials told MONch that the system has completed tests and that the firm is now awaiting customers, witnessing significant interest to this end.

TwInvis has already shown what it can do in several demonstrations to military customers, air traffic control organisations and other interested parties. Two TwInvis demonstrators have already been delivered to potential customers in Europe. (Photo: DPM)

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