J. J. García

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In recent applications based on ultrasound, several ultrasonic transducers have been geometrically and electronically associated to constitute a global sensor. There are several different methods used to process the ultrasonic signals obtained from these transducers. In this work, multimode techniques using Golay complementary sequences are proposed for(More)
In the current railway systems, it is becoming more necessary to have safety elements in order to avoid accidents. One of the causes that can provoke serious accidents is the existence of obstacles in railways, either fixed or mobiles. In this work, a multisensorial system is proposed in order to inform the monitoring system of the existence of obstacle.(More)
Many mobile robots and autonomous vehicles designed for outdoor operation have incorporated ultrasonic sensors in their navigation systems, whose function is mainly to avoid possible collisions with very close obstacles. The use of these systems in more precise tasks requires signal encoding and the incorporation of pulse compression techniques that have(More)
The present work shows a local positioning system (LPS) for mobile robots (MR) using simultaneous emissions in the ultrasonic beacons. In order to solve the problem of the simultaneous emission of the ultrasonic beacons, the well-known technique called direct sequence code division multiple access (DS-CDMA) is used. This technique modulates the ultrasonic(More)
This work presents an intelligent system, which allows to detect obstacles in railways, based on optical emitters. The sensorial system is based on a barrier of emitters and another of receivers, placed each one of them at one side of the railway. Apart from the disposition of the sensorial system, a codification method of the emission is also presented in(More)
In local positioning systems (LPS) that use active beacons placed in the environment, the knowledge of the precise position of these beacons is supposed by the positioning algorithms. Previously the positions of the beacons have been directly measured or indirectly deduced and entered to the positioning system. In this work, a self-calibration method for(More)
This work presents some methods to reduce false alarms in railway obstacle detection. The sensorial system is based on one barrier of infrared emitters and another of receivers, placed on opposing sides of the railway. Obstacle detection is achieved by the lack of reception in the detectors. On the one hand, the efficiency of the system is achieved with the(More)
This work describes the design of a ultrasonic local positioning system (ULPS) with large covered area. The beacons have been designed with a cylindrical PVDF transducer (piezofilm transducer) to which a conical reflector has been connected to enlarge the covered area and to guarantee 3D indoor positioning. The proposed ULPS for mobile robots (MR) uses(More)
In this paper, a new strategy to detect motion object in railway is presented, using vision and principal components analysis (PCA). For this purpose, a set of images of the railway static environment is first captured to obtain the transformation matrix that used in PCA. By means of this matrix, the successive images are projected in the transformation(More)
The encoding of emissions by complementary sets of sequences is usually used in communications and multi-sensor systems where asynchronous detection is required. These sets of sequences have ideal properties in the addition of their autocorrelation and cross-correlation functions. Furthermore, it is possible to obtain efficient correlation algorithms that(More)