Mobile radio base stations make it possible to employ innovative surveillance technologies. This is because each base station sends out a clearly defined and uninterrupted signal covering its surrounding area. This signal is reflected back by the subjects being surveyed, eg vehicles, airplanes flying at low altitude, or ships in a coastal region. When the original signal and its echoes are received, the location and the speed of the object can be calculated by intelligent algorithms allowing the signals sent out by several illuminators to be fused and tracked over time.

Certain signals are always transmitted by the base stations, even when no mobile radio calls are being made which makes continuous surveillance possible. This is referred to as passive radar.

Achieving greater coverage and accuracy

The global propagation of mobile radio systems makes the use of base stations for passive radar operation possible, particularly in remote regions of the world and as part of the Bundeswehr’s out-of-area operations. The presence of multiple illuminators facilitates the fusion of many bistatic configurations with only one receiver station. This makes it possible to achieve greater coverage and accuracy.

The results flow as important elements into a variety of ongoing military and civilian type security research projects promoted by the EU or national institutions. They serve to close observation gaps in areas such as air surveillance, the perimeter control of military bases, coastal surveillance and green and blue border control (land and sea border control). Processes derived from these projects can also be used to exploit other illuminator sources such as WLAN stations surveying airport terminals and protecting critical infrastructures.

Emitter location: Reconnaissance of hostile communication networks

In current and future Bundeswehr missions against asymmetrically operating enemies it is vital that their Network Enabled Capabilities (NEC) are taken into consideration. Such hostile methods will, as a rule, be based on the use of communication networks which send out electromagnetic radiation during operation, meaning, in principle, that important aspects of their capability are accessible to sensor system based reconnaissance. Cellular mobile radio systems in which all mobile subscribers that communicate with a base station share a single frequency channel in addition to the emitter location, cause particular problems in the urban environment. All available information sources must be used to solve these problems. These can include array-antenna technology with demanding array-signal processing; the measurement of angles and frequencies from geometrically favorable positions such as the deployment of small airborne platforms (UAS: Unmanned Aerial Systems), and the best possible interpretation of the measured variables over the course of time by means of the tracking and fusion of heterogeneous sensor data. Emitters such as mobile radio equipment, communication nodes and satellite navigation system jammers are of particular interest.