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.

Trends in communications satellite platform design

Abstract: For more than twenty years, communications satellite manufacturers, launch vehicle providers, and satellite operators have participated in the gradual evolution of the satellite communications business. Deregulation, changing business climates, and major changes in the telecommunications market are contributing to dramatic shifts in the perception of satellites as part of an integrated communications strategy. The latest generation of satellite platforms introduces capabilities to support new kinds of services, and to radically change the way satellites are manufactured.

On the optimisation of distributed ambiguity ratio and directivity for a synthetic aperture radar

Abstract: Space borne Synthetic Aperture Radar (SAR) is a radar capable of high resolution imaging of the surface of the earth. Typical applications of a space borne SAR include the observation of oil slicks, ice packs, shipping lanes, industrial pollution and agricultural usage. The SAR spacecraft travels in a low earth orbit focusing a narrow radiation pattern upon the earth in the direction along the plane of travel and a wide beam in a plane transverse to this. Whereas the narrow along track or azimuth beam is fixed normal to the spacecraft, the wide elevation beam must have the ability to scan over the surface of the earth. The objective of this paper is to describe a new method of determining the array excitations that form this wide elevation beam taking account of both the antenna and the radar system characteristics.

Process for surface treatment and for deposition of polyaniline for absorbing light

Abstract: Deposition of polyaniline layer on titanium comprises electropolymerization after hydrofluoric/nitric acid pickling, chemical conversion treatment and hydrolysis. Preferred Features: A titanium (alloy) substrate may be initially treated by alkaline degreasing for 10-15 minutes at 55-65 degrees C in a bath containing 36-44 g/l sodium tripolyphosphate (Na5P3O10), 40 g/l sodium tetraborate (Na2B4O7.10H2O), 10 ml/l Ref. 631 surfactant and sodium hydroxide to give pH 8.5-9.5 and by abrasive grit blasting to a surface roughness (Ra) of 10-30 mu m. The hydrofluoric/nitric acid pickling is carried out for 2-2.5 minutes at 18-22 degrees C in a bath containing 100-180 ml nitric acid (41 degrees Be), 40-60 ml hydrofluoric acid (48%), 1 g F68 additive, 1.5 g TA6V (metal) and 11 qsp distilled water. The deposit is baked at 40-160 degrees C for 30 minutes to 2 hours.

On-orbit demonstration of automated closure and capture using ESA-developed proximity operations technologies and an existing, serviceable NASA Explorer Platform spacecraft

Abstract: The European Space Agency (ESA) has been working to develop an autonomous rendezvous and docking capability since 1984 to enable Hermes to automatically dock with Columbus. As a result, ESA with Matra, MBB, and other space companies have developed technologies that are also directly supportive of the current NASA initiative for Automated Rendezvous and Capture. Fairchild and Matra would like to discuss the results of the applicable ESA/Matra rendezvous and capture developments, and suggest how these capabilities could be used, together with an existing NASA Explorer Platform satellite, to minimize new development and accomplish a cost effective automatic closure and capture demonstration program. Several RV sensors have been developed at breadboard level for the Hermes/Columbus program by Matra, MBB, and SAAB. Detailed algorithms for automatic rendezvous, closure, and capture have been developed by ESA and CNES for application with Hermes to Columbus rendezvous and docking, and they currently are being verified with closed-loop software simulation. The algorithms have multiple closed-loop control modes and phases starting at long range using GPS navigation. Differential navigation is used for coast/continuous thrust homing, holdpoint acquisition, V-bar hopping, and station point acquisition. The proximity operation sensor is used for final closure and capture. A subset of these algorithms, comprising the proximity operations algorithms, could easily be extracted and tailored to a limited objective closure and capture flight demonstration.