IR sensor array configuration and signal processing for detecting obstacles in railways

This work describes a sensor array based on optical emitters, which allows to detect obstacles in railways. The sensorial system consists of a barrier of emitters and another of receivers, placed at opposite sides of the railway. Apart from the disposition of the sensorial system, it is necessary a codification method for the emission in order to detect the reception or the non-reception of transmissions between an emitter and a receiver. The method is based on a signal codification using complementary sequence pairs, suitably adapted for their simultaneous emission through the transmission channel. A high reliability under adverse conditions is achieved with the developed system, being possible to detect the presence of obstacles, and to inform about their situation.