RADAR IN THE SERVICE OF DEFENSE
Reconnaissance in crisis areas, surveillance of the airspace, protection of military vehicles: When it comes to defense, radar is a key technology – after all, it allows for the radio-based detection and measurement of objects. Fraunhofer FHR's Business Unit Defense offers a high degree of expertise in radar technologies that are frequently used by the Federal Armed Forces and the military industry.
Air Space Surveillance and Radar Imaging for Remote Reconnaissance
An important task of the Federal Armed Forces consists in detecting objects in airspace and low Earth orbit, whether these are aircraft, rockets, or even satellites. Therefore, the radar systems developed in the Business Unit Defense on the one hand, monitor the airspace from Earth – with the radar systems looking up into the air from the ground. On the other hand, radar systems mounted on aircraft or satellites monitor Earth from above. Such an image-based distant reconnaissance allows for the measurement of both buildings and other static objects as well as moving objects such as cars and trucks. Another task of radar systems consists in determining target classes. For example, helicopters, rockets, or similar objects are distinguished in the air, while individual buildings and even the types of agricultural areas can be recognized on the ground.
A general trend that is starting to emerge in the radar field: The use of higher frequencies is increasing. On one hand, this makes it possible to implement smaller and lighter radar systems and on the other hand, the usual frequency range is getting crowded due to increasing mobile communications and wireless networks. With its 300-gigahertz radar, the Business Unit Defense is in the big leagues on an international level
Further Radar Developments for Defense
Radar is also a practical solution for some close range issues as well as it is capable of imaging the surroundings even in darkness or foggy conditions. This can be important on drones or other unmanned flying objects, on robots, or on vehicles, for instance. On military vehicles, it is possible to recognize when the vehicle is being fired on: For example, when a grenade is approaching, the tenths or even hundredths of a second are crucial to be able to initiate active protection measures. The Business Unit Defense implements the radar detection of projectiles required for active protection.
Any attempts undertaken by other countries to explore the circumstances in Germany are in no way appreciated. For this reason, the Business Unit Defense also works on deceiving or jamming radar systems with the corresponding transmitters – to impede or prevent any exploration by this means. Passive radar is an ideal solution to conceal one's own observations and to thus protect them against these types of jamming attempts. In doing so, you do not emit the signals yourself but instead use the radio waves of others to monitor the airspace – without making yourself noticeable. The Business Unit Defense was also productive in applying its expertise in this area of concealed reconnaissance: It developed the passive system for air surveillance.
Cognitive radar is still a rather new field of research for the Business Unit Defense. Achieving the optimum setting of a radar system for its use is usually a complex challenge. The aim for the future is for radar to be able to carry out its parameterization itself and adapt it to the task based on its own intelligence since it makes a big difference if images of areas with high mountains or over the ocean with powerful waves have to be obtained. Excellent results have already been achieved in this area of cognitive radar. Other, still relatively new, research fields are the design of metamaterials – i.e. materials with properties that do not exist as such in nature – allowing for special features in antenna design – and coherent radar networks in which multiple transmitters and receivers work together to emit their signals fine-tuned to each other.