Matra

About: Matra is a based out in . It is known for research contribution in the topics: Signal & Detector. The organization has 1330 authors who have published 1216 publications receiving 17967 citations.

Non linear estimation in sonar tracking

Abstract: This paper presents an optimal recursive algorithm with a new adapted state representation for the bearings-only tracking problem. We apply nonlinear filtering techniques to derive the optimal filter. State estimation, which consists of initial position and velocity both in polar coordinate is achieved by a space discretization of the optimal filter. To apply this time-consuming approach in realistic situations, this paper presents an adaptative grid computational scheme where the integration step is controlled by the a priori probabilities. We compare this new solution to the maximum a posteriori estimator and perform Monte-Carlo simulations to compare both algorithms performance.

Weaving device for making a structure for a composite article

Abstract: The composite fabric weaving has a longitudinal cam to move the warps, and a structured weft insertion system. The assembly for weaving a composite material has a system (5) to give different displacement movement speeds to the warps (FC) which rotates round a longitudinal axis (X-X). Its profile is set as a function of at least one lateral edge of the woven material, in a cam shape. The cam (5) has a flat surface and a profile which is defined by a variable lateral width, at right angles to the axis (X-X), where the axis is generally orthogonal to the direction (D) of the warps (FC). The cam profile is defined so that the lateral width (hi) is at a point (Pi) along the axis (X-X) to meet the equation: Li= n(Pj)+F1(hi,θ 2) - F2(hi,θ 1) where: Li is the required length of the warp in the woven fabric at the point (Pi) on the longitudinal axis (X-X); n is the number of wefts in the fabric; n Pj is the displacement of the warps in each step; F1 and F2 are the distance functions of the lateral width (hi) and the extreme rotation angles (θ 1, θ 2) of the cam. The weft insertion system gives a variable number of superimposed wefts of different weft thicknesses. The length of warp displacement, with longitudinal displacement by steps for the insertion of the wefts, is set for each step.

The potential use of HTS filters in satellite payloads

Abstract: The surface resistance values for various thin films (YBaCaCuO, GdBaCuO and TlBaCaCuO) already show significant improvements over conventional conductors on various substrates. Low loss YBCO and TlBaCaCuO thick films on yttria-stabilised zirconia (YSZ) have been reported by Birmingham and Oxford Universities respectively. Thick films have the added advantage that they can coat large area curved surfaces. A method to characterise HTS materials and substrates using a ring resonators has been developed by Portsmouth University, and measurements on TlBaCaCuO rings are being undertaken. A 4-pole extracted pole filter fabricated from GdBaCuO was commissioned from Marconi Research Centre (MRC). It has been characterised for MMS by Portsmouth University over two temperature cycles between 50 K and 90 K. Excellent reproducibility was seen over each temperature cycle with the supplied data from MRC. The design of a 4-pole elliptic filter using TlBaCaCuO on an MgO substrate is discussed. Work on single crystal dielectric resonator filters is ongoing. The significant advantages and disadvantages of DR/HTS technology have been assessed and are discussed.

Environmental prediction and radiation effects of protons into solar generators: application to HIPPARCOS revised mission

Abstract: A new analytical technique for predicting solar array degradation is presented and applied to the HIPPARCOS revised mission. This methodology developed in the new version of the software GSPOWER allows the treatment of the degradation due to protons and electrons separately. >

Photogrammetry From Spot With Matra Traster Analytical Plotter

Abstract: Photogrammetry consists in taking a photo from the same part of the ground with the same camera but from two different places and then use this pair of pictures for stereoplotting Stereoplotting consists in placing the stereopair of photos into the two projectors of an optical and mechanical stereoplotter with the same interior orientation as the camera used Interior orientation of the camera is measured by calibration. Then relative and absolute orientation of two projectors are done. This mean orientate the two projectors into the same relative and absolute position angles as were the camera during the shot. This is done taking at least three control points for hight and two control points in X and Y to match will the map manuscript plane. Nowaydays optico-mechanical plotters which have some limitations and are very long and difficult to operate are being replaced by analytical equipment which give : - better accuracy due to - simplier construction - digital corrections of parameters such as earth curvature, films deformation, atmospheric refraction lens distorsion. - faster operation typically 15' for model orientation instead of one or one and half hour. - larger field of application, no limitation of : - focal lens of camera, - convergence.