Cassidian, the defence and security division of EADS, has developed what is known as ‘passive radar’ that can locate even difficult-to-detect flying objects such as stealth aircraft and that itself is practically undetectable. In contrast to conventional radar, passive radar doesn't emit any radiation, but instead analyses radiation reflections from other emitters, such as radio and television stations, to detect objects.
"The principle of passive radar has been known for a long time," said Elmar Compans, Head of Sensors & Electronic Warfare at Cassidian. "However, we have now integrated the latest capabilities of digital receiver and signal processing technology to significantly enhance range and detection accuracy by monitoring various emitters at the same time."
With its passive radar, Cassidian is focussing on the requirements of civil and military airspace control which until now could not or not sufficiently be met using active emitting radar. In civil application, passive radar makes cost-effective air traffic control possible without any additional emissions and without making demands on transmission frequencies in short supply. In military applications, the system enables large-area surveillance using networked receivers, while offering the decisive operational advantage that passive radar cannot be located by hostile forces.
The particular characteristics of the omnipresent radio signals used for operation enable detection of even objects that are difficult to detect, such as stealth aircraft or stealth ships. A further advantage of the new technology is its increased detection capacity in areas of radar shadow such as mountainous terrain and its capability to locate extremely slow and low flying objects.
A demonstration system has already been delivered to the German Federal Office of Defense Technology and Procurement (BWB). After successful testing, including at Stuttgart Airport, the plan is to set up a production prototype system and to carry out evaluation programmes by both Cassidian and the customer by the end of the year.