The Cirque de Gavarnie protected by StoneScan®

The Cirque de Gavarnie is a natural rock formation taking the form of a giant amphitheatre in the French Pyrenees Mountains. This extraordinary place has been scheduled by UNESCO organization. Hundred thousands of tourists come every year to visit it.

But the main access road is highly exposed to rock falls at the Chaos de Coumely place. Pyrenees administration in collaboration with the mountain technical center RTM, chose StoneScanâ system developed by Cesigma to protect the road along the fallen rocks area.

When a rock fall is detected by the system, traffic is interrupted at each side above the fallen rock area. After signal analysis from all sensors placed on the fallen rock, the road is opened in the absence of any danger or definitively closed. Then authorities are automatically warned by phone or radio transmission link.

StoneScanâ system is widely used to protect roads against rock falls and is currently evaluated by the French Railway Company to detect rocks on railways. StoneScanâ system uses acoustic-seismic sensors (Stone®) and/or Doppler radars (RadStoneâ) in order to detect rock falls.

Each sensor integrates a signal processing system which detects rock fall signatures and rejects the other noises and traffic, lighting strikes, etc. signatures. Sensor transmits numerical data to the control unit by high rate radio and optical fiber data link.

The control unit manages traffic lights and authority warning according to information and data transmitted by sensors which are placed over all the fallen rocks area.

Signal processing onboard performs a high detection rate and a high false alarm rejection by using optimized algorithms and massive real time calculation. Cesigma has developed a high speed multi-processor board designed for real time signal processing applications (Lagoon® boards).