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.

Infrared pushbroom camera breadboard using off-the-shelf 2D array of detector

Abstract: Performances for nowadays optronic systems require focal plane arrays (FPA) with an increasing number of detectors. The `push- broom' technic is well adapted to earth observation in the visible range with the availability of long linear CCD'S offering thousands of pixels. In the infrared, line scan systems are preferred at the present time because technological difficulties have to be overcome in order to get long linear arrays. Among the most important, are: (1) Difficulties to have a large cold focal plane with a temperature uniformity of a few degrees. (2) Difficulties to get good detection material over large surface. Mechanical or optical butting technology can be used there but with dead pixels and/or side effects. (3) Very low cold shield efficiency due to the geometry of the long linear array. (4) Very high development costs. MATRA DEFENSE UAO has made the design of a new infrared FPA concept which has the advantage to overcome all drawbacks listed previously (patented design). The idea consists to transform the pixel arrangement geometry of a 2D array which is available off the shelf into a long linear FPA using a coherent infrared fiber optic reformatter. In order to demonstrate the feasibility of this new FPA concept, a camera breadboard has been built. This task has been supported by the French MOD (STTE). This paper describes this breadboard and gives main technical performances.

Method and apparatus for measuring a relative movement between two elements

Abstract: For measuring an amount of relative movement between two elements, such as a vehicle and a track, which are mutually movable, two successive pulses of coherent light are directed from the vehicle to the track under a same incidence angle. From a same location of the vehicle, two images of the interference patterns due to the short pulses are formed. The two pulses are offset from each other in the direction of movement by a distance d approximately corresponding to the amount of relative movement between the two pulses. The actual amount of movement is computed as being the movement which provides the best coincidence between the two images. The comparison can be made by cross-correlation.

50–80K Pulse Tube Cryocooler Development

Abstract: A strong effort is being made world wide in developing miniature cryocoolers for multi-year space missions. These cryocoolers must satisfy strong requirements among which reliability, minimal exported vibration and efficient thermal performance are the most critical. Many cryocooler designs are under development. These designs include Stirling, Sorption and particularly Pulse Tube coolers. While this last technology is not new, major improvements have been made recently that promise significant benefits. Pulse tube coolers are very similar to Stirling coolers but they do not require any moving displacer in the cold finger and consequently no motorization, no synchronisation electronics, no bearings and clearance seals. This is very interesting in terms of mechanical simplicity, reliability, reduction of induced vibrations and electromagnetic noises. Performances comparable with those of Stirling coolers are achievable in terms of size, weight, cooling power, cooling temperature and efficiency.

The Atmospheric Lidar Instrument (ATLID)

Abstract: The paper describes the design and performances of the Atmospheric Lidar instrument. ATLID is a backscatter lidar and a candidate for a future Polar Mission of ESA (beyond ENVISAT-1). The instrument uses a solid-state Nd-Yag laser (1.06 μm wavelength) and a 0.8 m diameter telescope. A linear scanning (+/− 40°) ensures the required swathwidth (1400 Km). The selected concept consists of a lightweight scanning telescope associated to a contra-rotative flywheel for torque compensation.

Method and device for active damping of vibrations

Abstract: In order to damp the vibrations in a specified location subjected to a primary field of vibrations, a vibrational wave is generated which is intended to interfere with the primary field at this location, through adaptive filtering of a reference signal. The device comprises n processing channels each having a digital filter (14) for feeding an actuator (16), fed with a sinusoidal signal of frequency specific to the filter and corresponding to a concentration of vibrational energy of the primary field. The coefficients of the filter can be adapted by a specific loop which receives an error signal (e) and the input signal of the digital filter, filtered by a loop filter (18). The outputs from the channels are added together and applied to the actuator.