Showing papers by "Matra published in 1987"

Optical data transmission with frequency multiplexing

Abstract: A transmitter for multiplexing three optical channels at different wavelengths has (a) first, second and third laser diode means delivering linearly polarized optical beams at respective wavelengths λ2, λ3 and λ4 which are mutually different; (b) an assembly located in the path of the light of wavelength λ2 emitted by said first diode means and including a plate which is substantially quarter-wave for the wavelength (2 λ2-λ4), a filter having a band pass centered on wavelength λ2, a plate quarter-wave which is substantially for wavelength λ4 and a polarizer, the first diode means being oriented so that its beam is transmitted by the polarizer. A first light beam combiner directs light from said third diode means onto the polarizer along a direction of 90° from the direction of the beam of wavelength λ2 and with the same polarization direction, so that the beam of wavelength λ4 is reflected towards said filter. A second combiner directs the light from said second diode, having wavelength λ3 intermediate between λ2 and λ4, onto the polarizer in a direction opposite to that of the light beam of wavelength λ4 and with a polarization of the same direction, so that the light of wavelength λ3 is reflected along a path coaxial with the output path of the light having wavelength λ2 and λ4. More than three channels may be combined.

Warhead for missiles

Abstract: A warhead for a guided missile initiated by a proximity fuse, for use against high speed high altitude targets, comprises a fragmentation casing, an outer explosive charge contained in the casing and having a detonator and an inner explosive charge radially separated from the outer charge by an empty space. The inner charge has a detonator and is so arranged that the outer charge is detonated by the shockwave travelling through the radial space. On the other hand, the inner charge does not detonate following explosion of the outer charge. The charges are so shaped that the fragments from the casing are distributed as a radially directed isotopic shower.

Mine with indirect firing for attacking armoured vehicles

Abstract: A mine for use against armored vehicles has a mount with a base resting on the ground and an ammunition launching tube having a fixed elevation and carried by the base for rotation about a vertical axis. The base contains a system for detection and azimuth location of targets which uses both seismic and acoustic detection. The tube is aimed in azimuth toward the target and an anti-tank ammunition is fired toward the position where the distance between the mine and the target is minimum. The ammunition consists of a self-propelled missile which will fly over the target at a high speed. The motor of the missile spins it about its roll axis. The self forging charge of the missile has an axis transversal to the roll axis. The missile has a detection system including a sensor which scans the ground about the roll axis and causes firing of the charge when aligned with the target.

A “box-scheme” for the euler equations

Abstract: For the solution of first order partial differential equations with boundary conditions a box scheme is introduced based on a compact discretization in space and the use of the characteristic directions for the integration in time. The scheme is first developped for a non-linear scalar conservation law. Then it is presented for the equations of gas dynamics in a domain of varying area. Applications to the shock tube and to a steady flow in a nozzle exhibit the major features of the scheme. Preliminary results in two-dimensions seem to indicate that the extension is worthy of interest.

Method and device for optical distance measurement

Abstract: Le procede permet de mesurer la distance entre un chasseur (12) et une cible (10), ainsi que la position relative de la cible, definie par les angles α et β. The method enables to measure the distance between a hunter (12) and a target (10), and the relative position of the target defined by the α and β angles. On emet a partir du chasseur vers la cible et de facon repetitive, des impulsions lumineuses sensiblement monochromatiques et on recueille le flux lumineux reflechi par la cible sur un detecteur matriciel a lecture par transfert ligne a ligne ou point a point ; Transmitting from the hunter toward the target and repeatedly, substantially monochromatic light pulses and collecting the light flux reflected by the target on a read transfer matrix detector line by line or point to point; on effectue le transfert, a frequence determinee, pendant le retour de l'echo et la sequence d'emission, de recueil et de transfert est repetee pour au moins deux frequences de transfert differentes, la distance etant deduite du decalage (h1-h2) entre des lignes ou points ayant recu l'echo pour les deux frequences differentes. is performed the transfer, determined frequency, during the return of the echo and the transmission sequence, collection and transfer is repeated for at least two different transfer frequencies, the distance being derived from the difference (h1-h2) between lines or dots having received echo for the two different frequencies.

Method and device for measuring distance optically

Abstract: For optical measurement of a distance between a hunter and a target, for instance between satellites, back-reflecting means are provided on the target. The hunter carries a source of substantially monochromatic light pulses and a solid state detector having a matrix of sensors. The matrix is read-out by transferring the contents of the sensors line per line or point per point at a predetermined frequency to an output memory. A time base triggers one pulse at a predetermined time selected for causing return of an echo from the target during read-out. The distance is derived from a determination of that line or that point which receives the echo, for two different transfer frequencies.

Motor vehicles equipped for decontamination purposes

Abstract: A motor vehicle for the decontamination of terrain and equipment and of personnel with at least one chemical dispersing device and spraying devices on the vehicle is provided having a module box placed on the vehicle frame in which the means for terrain and equipment decontamination are located, and a second module box placed on the vehicle frame and removable from it in a well known manner onto the ground, in which all the equipment required for the decontamination of personnel are located, and two tents can be built onto it and a shower arrangement is located on its rear side.

Facility for decontamination cleaning of people

Abstract: Facility for decontamination cleaning of people, having a room bounded by foldable side and roof panels and intended for undressing, and a second room bounded by further foldable side and roof panels and intended for dressing, and having a shower device with showers 26 and a shower water collecting trough 22, and an assembly box 13 for containers and cleaning agents and accessories, the entire facility with the exception of the shower device being arranged inside this box 13 in the transporting state and the shower device being folded on to the rear wall 20 of this box 13, whereas in the operating state the showers 26 are folded up and the shower water collecting trough 22 is folded down and the roof panels are formed by flexible panels pulled out of roller boxes 17.

Optical frequency multiplex data transmission device

Abstract: Le dispositif comprend un emetteur muni d'un multiplexeur et un recepteur muni d'un demultiplexeur. Le multiplexeur comporte au moins trois diodes laser fournissant des faisceaux optiques polarises a trois longueurs d'onde λ₂, λ₃, λ₄. Sur le trajet λ₂ est interpose un ensemble comportant une lame (16) quart d'onde pour la longueur d'onde (2λ₂ - λ₄), un filtre (18) de transmission de la longueur d'onde λ₂, une lame (20) quart d'onde pour la longueur londe λ₄ et un polariseur (22), la diode de longueur d'onde λ₂ etant orientee pour que son faisceau soit transmis par le polariseur. La longueur d'onde λ₄ est dirigee sur le polariseur a 90° de la longueur d'onde λ₂ et avec la meme polarisation. La longueur d'onde λ₃, intermediaire entre λ₂ et λ₄, est dirigee sur le polariseur (22) a l'oppose de la lumiere d'onde λ₄ et avec une polarisation de meme sens, de facon que la lumiere de longueur d'onde λ₃ soit reflechie suivant un trajet coaxial au trajet de sortie des longueurs d'onde λ₂ et λ₄.

Laser Diodes Communications For The European Data Relay System

Abstract: The use of optical communications for the high data-rate links of the future European Data Relay Satellite System has been receiving growing attention for the past few years. This paper presents a system design based upon GaALAs laser diodes transmitters and direct-detection receivers. A Wavelength Division Multiplexing technique is used to accomodate data-rates up to 500 Mb/s on the return link with moderate antenna diameters. Si CCD matrices are used as acquisition and tracking sensors, and angular error informations are extracted directly from the communication signal, thus avoiding the need for a dedicated tracking beacon. Expected performances are given ; The system is shown to be capable of supporting variable user requirements. The architecture of the terminals, including adequate redundancies, is described. Mass estimates are given.

Design Of A Wavelength Division Multiplexing/Demultiplexing System For Optical Intersatellite Links

Abstract: Optical communications is an alternative to the microwave solution for high data rate interorbit (IOL) or intersatellite link (ISL), typically 500 Mbit/s.The optical system, using laser diode technology, only requires small size antennae, provided that multiplexing or power combining techniques are used.This paper presents a Wavelength Division Multiplexing/Demultiplexing System involving orthogonal polarizations for adjacent channels. This solution is preferred to the power combining technique to satisfy some specific system and interfaces constraints and to avoid a very accurate control of laser wavelength.The proposed design complies with system constraints like redundancy, minimum back­ light on the laser junction, interchannel interferences, depolarization in the optical system, compacity, ... Its simplicity -the required components are only A/4 plates, filters under normal incidence and polarizer beamsplitters- is attractive and the concept, descri­ bed here for 4 wavelengths in the 0.817-0.843 \i range, can be applied to an unlimited number of wavelengths. The computed performances in transmission and isolation taking into account all parasitic reflections are given.A breadboard model is currently under development at MATRA to be tested in 1987. Preliminary results of sub-assemblies tests are presented.IntroductionLaser diodes technology offers many advantages for intersatellite communications. However, its application to Data Relay Satellite, which is currently studied in Europel, must overcome power limitations to support the required high data rate around 500 Mbit/s. In fact, today available components exhibiting good quality beam are single longitudinal mode, index guided devices, whose reliable power is limited to about 50 mW. To circumvent this limitation, two methods can be envisaged :- power combining,- multiplexing/demultiplexing (or WDM)The first technique increases by different means ' the output power transmitted to a single APD-receiver, while WDM technique associates a receiver to each wavelength and then requires data channelization. This second approach has been selected for the future EDRS (European Data Relay Satellite).Selection of the WDM techniqueTaking into account the European Data Relay Satellite requirements, namely a great operational flexibility -particularly to transmit independant data from different payloads on the same satellite-and 120 Mbit/s channelization in the feeder link, the WDM technique is particularly suitable. To provide about 500 Mbit/s interorbit communications, a 4 channels system (each one with 120 Mbit/s) has been considered.MATRA studies have lead to a MUX/DEMUX concept which is the subject of a Patent appli­ cation.The functional block diagram is described in figure 1, where redundancies are implemen­ ted at component level (2 diodes per wavelength) as well as subsystem level (2 multiplexer assemblies) in view to satisfy the reliability requirements (0.9 for 5 years on LEO).Selected concept A. SpecificationsA.I Laser diodes available wavelengths : commercially available single mode diodes in the 0.8 |i region are double heterostructure GaAs/GaAlAs components. Their wavelength distribution looks like what is shown on figure 2. The available wavelength range is then limited to 815-845 nm.

Method and device for determining the quality of an optical instrument, especially its transfer function

Abstract: For measuring the optical transfer function of an optical instrument having an input pupil, a device comprises a source of spatially coherent light for illuminating the pupil of the instrument. Two separate zones are isolated in the input pupil of the instrument by a system comprising a grating, a lens for forming an image and a spatial filter which eliminates the zero diffraction order. The two zones have a spacing which is in direct relation to the spatial frequency. The position and mutual spacing of the fringes are determined. A computer derives the transfer function from the measurements made for a plurality of pairs of zones.

Mine à tir indirect d'attaque de véhicule blindé

Abstract: La mine comprend un affut (10) ayant un socle (14) conte­nant un systeme de detection et de localisation en azimut de cible par voie sismique et acoustique (20) et au moins un tube de lancement de munition (26), orientable en gisement par ledit systeme pour projeter la munition (12) a site fixe vers la position ou la vitesse angulaire de la cible est maximale. La munition (12) est autopropulsee par des moyens qui la maintiennent en rotation autour de son axe de roulis, contient une charge a generation de noyau (dite CGN ou SFF) d'axe transversal a l'axe de roulis, et est munie de moyens de detection de cible a balayage autour de l'axe de roulis, provoquant la detonation de la charge lorsqu'elle est dirigee vers la cible.

System Analysis Of Optical Interorbit Communications

Abstract: In view of the European Data Relay Satellite, a system based upon GaA1As laser diodes transmitters and direct detection receivers has been proposed. This paper addresses the problem of link-budget optimization and focuses on its interrelation with acquisition, pointing and tracking performances. Possible means for supporting variable communications requirements are proposed ; the main characteristics of possible USER-terminal "standards" are briefly outlined.

Cylinder firearm, and an associated improved cylinder

Abstract: The invention relates to a cylinder firearm whose cylinder (100) includes a plurality of chambers (108). The cylinder (100) includes a channel (101) associated with each of its chambers (108) and opening out into said chamber ahead of any cartridge contained therein, with the other end of each channel receiving a piston (111), which piston presses against the frame of the gun when fired, thereby causing the cylinder to move forwardly by reaction and thus suppressing the operating clearance provided between the cylinder and the barrel and thus providing good sealing at the front of each chamber when fired. The invention is particularly applicable to revolvers.

Arme à feu barillet, et barillet perfectionné associé

Abstract: L'invention concerne une arme a feu a barillet, dont le barillet (100) comporte une pluralite de chambres (108). Conformement a l'invention, le barillet (100) com­porte un canal (101) associe a chaque chambre (108) et de­bouchant dans ladite chambre en avant de la douille, l'au­tre extremite du canal recevant un piston (111), lequel piston vient en appui contre la carcasse de l'arme lors de la mise a feu et provoque par reaction un deplacement du barillet vers l'avant pour supprimer le jeu de fonctionne­ment entre barillet et canon et realiser une parfaite etan­cheite avant de la chambre de combustion. Application notamment a la realisation de revol­vers a barillet.

Procede et dispositif de determination de la qualite d'un instrument optique et notamment de sa fonction de transfert

Abstract: UN DISPOSITIF DE MESURE DE LA QUALITE OPTIQUE D'UN INSTRUMENT, ET NOTAMMENT DE SA FONCTION DE TRANSFERT, COMPREND UNE SOURCE 10 DE LUMIERE SPATIALEMENT COHERENTE, DES MOYENS DESTINES A DECOUPER DEUX ZONES DISTINCTES DANS LA PUPILLE D'ENTREE DE L'INSTRUMENT 14 A ETUDIER A PARTIR DU FAISCEAU DE LUMIERE FOURNI PAR LA SOURCE, ET DES MOYENS 32 D'ANALYSE DES FRANGES FORMEES DANS LE PLAN IMAGE DE L'INSTRUMENT. CES MOYENS, CONSTITUES PAR UN RESEAU EN LUMIERE MONOCHROMATIQUE, DONNENT AUX DEUX ZONES UN ECART PROPORTIONNEL A LA FREQUENCE SPATIALE DE TRAVAIL. LE DISPOSITIF COMPREND DE PLUS DES MOYENS DE MESURE PERMETTANT DE DETERMINER EGALEMENT L'ECARTEMENT DES FRANGES ET DES MOYENS DE CALCUL DE LA FONCTION DE TRANSFERT, PAR INTEGRATION A PARTIR DE MESURES DE L'ECARTEMENT ET DE LA POSITION DES FRANGES POUR PLUSIEURS COUPLES DE DEUX ZONES DISTINCTES, CORRESPONDANT A L'ENSEMBLE DE LA SURFACE DE LA PUPILLE.