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Concept

Balise (transport)

Résumé

vignette|La balise Baltimore Beacon en Irlande. vignette|Vieille balise submergée dans un fjord de Lysekil (commune), Suède. Juin 2020. Une balise est un dispositif conçu pour attirer l'attention sur un emplacement spécifique. Elle peut être combinée avec des indicateurs fournissant des informations importantes, en particulier dans le domaine des transports (aéronautique, maritime, routier, ferroviaire). Notes et références Catégorie:Transport Catégorie:Signalisation

Source officielle

https://fr.wikipedia.org/wiki/Balise_(transport)

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Les télécommunications sont définies comme la transmission d’informations à distance en utilisant des technologies électronique, informatique, de transmission filaire, optique ou électromagnétique.

vignette|Télégraphe de Cooke et Wheatstone à cinq aiguilles de 1837. vignette|Télégraphe de Morse vignette|Télégraphe de David Edward Hughes, un téléscripteur construit en 1855 par Siemens et Halske.

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Cours associés (2)

The course teaches the basics of autonomous mobile robots. Both hardware (energy, locomotion, sensors) and software (signal processing, control, localization, trajectory planning, high-level control) will be tackled. The students will apply the knowledge to program and control a real mobile robot.

The main objective of the course is to introduce the concept of space system design and engineering. The course will describe the various subsystems involved in the design of a satellite. It will also describe the techniques of systems engineering that are used to obtain a coherent satellite design.

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Dynamic bending compensation while focusing through a multimode fiber

Salma Farahi, Christophe Moser, Demetri Psaltis, David Ziegler

Multimode fiber endoscopes have recently been shown to provide sub-micrometer resolution, however, imaging through a multimode fiber is highly sensitive to bending. Here we describe the implementation of a coherent beacon source placed at the distal tip of the multimode fiber, which can be used to compensate for the effects of bending. In the first part of this paper, we show that a diffraction limited focused spot can be generated at the distal tip of the multimode fiber using the beacon. In the second part, we demonstrate focusing even when the fiber is bent by dynamically compensating for it. The speckle pattern at the proximal fiber end, generated by the beacon source placed at its distal end, is highly dependent on the fiber conformation. We experimentally show that by intensity correlation, it is possible to identify the fiber conformation and maintain a focus spot while the fiber is bent over a certain range. Once the fiber configuration is determined, previously calibrated phase patterns could be stored for each fiber conformation and used to scan the distal spot and perform imaging. (c) 2013 Optical Society of America

Optical Society of America2013

Chargement

A Galileo E1b,c RF Front-End Optimized for Narrowband Interferers Mitigation

Cyril Botteron, Frédéric Chastellain, Pierre-André Farine, Davide Manetti, Giuseppe Zamuner

The current Search and Rescue (SAR) service, which is based on the Cospas-Sarsat system, suffers from major limitations such as poor position accuracy, long alert times and high false alarm rate. Two types of distress signals are used, the first 121.5MHz/(up to 100mW) and the second 406MHz/5W, the latter being able to carry digitally encoded identification and position data. The Galileo system will importantly contribute to the improvement of the SAR system. Indeed, the Galileo satellites will include a transponder in order to re-broadcast the 406MHz message, which will allow a better coverage (27 Galileo satellites plus the current seven Cospas-Sarsat satellites) and also a shorter alert time. They will also include a return link message (RLM) in the Galileo E1b open service signal, which will reduce the number of false alarms. The Galileo system is therefore a great opportunity for the development of a new generation of beacons which will include a Galileo receiver and therefore be able to take advantage of the better coverage provided by the Galileo constellation to provide shorter alert times and of the RLM to reduce the number of false alarms. One of the major issue when designing a Galileo receiver to be operated in a distess beacon is to design a front-end that is sensitive enough to pick the very weak Galileo signals and on the same time rejects the strong distress messages. Indeed, when the beacon is turned on, the Galileo receiver is in cold start conditions and a short amount of time is left to the receiver to get a first fix before any distress message is actually emitted. However, in some cases, the receiver is not able to determine its position sufficiently fast and the front-end therefore has to acquire the satellites in the presence of the distress signals. This paper presents a Galileo radio frequency front-end designed in order to operate in the presence of such signals.

2006

Chargement

A flexible Galileo E1 Receiver Platform for the Validation of Low Power and Rapid Acquisition Schemes

Marcel Baracchi Frei, Cyril Botteron, Frédéric Chastellain, Pierre-André Farine, Davide Manetti, Giuseppe Zamuner

With the inclusion of 406 MHz transponders on the Galileo satellites and the new search and rescue (SAR) return link message (RLM) on the open service E1B signal, the availability of distress beacons equipped with a Galileo or combined GPS/Galileo receiver will be very important in the future to take advantage of the SAR RLM, thereby facilitating the rescue operations and helping to identify and reject false alerts. Consequently, this paper provides the status of the development of a flexible Galileo L1 receiver platform as well as an analysis and comparison of acquisition schemes suitable to be implemented in 406 MHz Cospas-Sarsat distress beacons. For each considered acquisition scheme, we compare the acquisition performance that can be obtained using GPS L1 C/A or Galileo E1B or E1C signals and consider and discuss the following main constraints: a very short time to first fix (TTFF) in cold start conditions (the beacon’s GNSS receiver may not be powered on for years before it is activated in an emergency); a low energy consumption per position fix (the beacon and GNSS receiver are battery powered); a possibly long coherent integration time to achieve synchronization and tracking in harsh environments (e.g., when some or all of the satellite signals are blocked or attenuated by an obstruction); the ability to demodulate the satellites signals in the presence of a 406MHz/5W and a 121.5MHz/(up to 100mW) beacon transmitters; and a low complexity (low price).

2006

Chargement

A Galileo E1b,c RF Front-End Optimized for Narrowband Interferers Mitigation

Cyril Botteron, Frédéric Chastellain, Pierre-André Farine, Davide Manetti, Giuseppe Zamuner

2006