On 29 October 2019 – The passive radar "TwInvis" of sensor solution provider HENSOLDT showed outstanding detection performance during a measurement campaign of the NATO Science and Technology Organization under the leadership of the Polish armed forces.

For this purpose, a passive radar sensor cluster with two sensors was installed on the Polish Baltic coast. During the measurement campaign, a system integrated in a container was used alongside a system variant integrated in a van. TwInvis reliably detected a large number of targets in the air and at sea, ranging from light aircraft and combat aircraft to ballistic and ground-to-air missiles. The achieved ranges over the Baltic Sea coast were up to 300km. The live data from the TwInvis cluster were fed into the Polish MilRad network and analysed and evaluated in a nearby Polish CRC.

A passive radar acts purely as a receiver, i.e. it does not transmit itself, and locates aircraft by evaluating the signals reflected at the target from existing external transmitters. The TwInvis is creating a comprehensive air situation picture, which is generated from the simultaneous evaluation of a large number of frequency ranges. TwInvis is able to simultaneously evaluate up to 16 FM transmitters (analogue radio) and 5 frequencies with several contributing transmitters from DAB and DAB+ (digital radio) as well as DVB-T and DVB-T2 (digital terrestrial television) due to its highly developed digital receiver technology and special algorithms. 

In civil applications, passive radar enables low-cost control of air traffic without additional emissions and without using scarce transmission frequencies. In military applications, the system enables covert surveillance of large areas using networked receivers and offers the advantage that the "passive radar" cannot be located by the enemy and is very difficult to be jammed.