Through-Wall sensing system uses software-defined radio
After floods, earthquakes and similar natural disasters or after bomb explosions, rescue teams often face the problem of not knowing where to look for missing persons under the rubble. The system developed by the BFH can use radio waves to provide information about buried victims and thus provides support for police and fire brigade operations. Under well-suited conditions, the system is even able to detect respiratory movements and the heartbeat.
At ETH Zurich, a prototype of a “Through Wall Sensing” system was recently developed with which movements of persons behind a wall can be detected. The changing propagation conditions are evaluated by multipath reception of a sinusoidal high-frequency test signal. Researchers at the Bern University of Applied Sciences were commissioned by armasuisse Science and Technology to analyse, optimise and miniaturise the ETH system.
The aim was to develop a compact and cost-effective demonstrator with the help of the Software Defined Radio (SDR) platform developed at the BFH. Up to now, current systems have been much more cost-intensive and complex and, depending on the local legal situation, may even require frequency approval by the authorities in many countries.
Software Defined Radios (SDRs) offer enormous flexibility. With these systems, the required transmission signal is first generated by software and then physically converted. To receive a radio signal, the procedure is reversed accordingly. Thanks to the advances in the performance of digital components, modern, complex mobile radio standards such as LTE or UMTS can now also be implemented using SDRs.
The system developed by the BFH allows flexible use and thus has enormous potential for further development: On the one hand due to its compact dimensions, its universal connectivity possibilities, on the other hand due to the great openness with regard to the definition of measurement signals and their evaluation possibilities.
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