Statistical Resolution Limit for Source Localization With Clutter Interference in a MIMO radar Context

International audienceDuring the last decade, multiple-input multiple-ouput (MIMO) radar has received an increasing interest. One can find several estimation schemes in the literature related to the direction of arrivals and/or direction of departures, but their ultimate performance in terms of the statistical resolution limit (SRL) have not been fully investigated. In this correspondence, we fill this lack. Particulary, we derive the SRL to resolve two closely spaced targets in clutter interference using a MIMO radar with widely separated antennas. Toward this end, we use a hypothesis test formulation based on the generalized likelihood ratio test (GLRT). Furthermore, we investigate the link between the SRL and the minimum signal-to-noise ratio (SNR) required to resolve two closely spaced targets for a given probability of false alarm and for a given probability of detection. Finally, theoretical and numerical analysis of the SRL are given for several scenarios (with/without clutter interference, known/unknown parameters of interest and known/unknown noise variance)

Synthesis of vanadium oxides 5 wt.%VO 2 –M x O y by sol–gel process and application in cyclohexene epoxidation

International audienceA series of Si02, Al203 and TiO2 mixed vanadium materials have been prepared from inorganic precursors via the sol gel process and subsequently dried, calcined and reduced at elevated temperatures. Structural characterization of these materials was carried out by X-ray diffraction (XRD), N2 adsorption at 77K, thermal analysis (TGA/DTA), UV-vis diffused reflectance spectroscopy (DR UV-vis) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDX). Their catalytic activities in the epoxidation of cyclohexene with TBHP as oxidant were also examined. Results of XRD and DR UV-visible diffused revealed that V02 species are predominant in all samples and no formation of V205 was detected. Experimental results indicated that the V02 Si02 catalysts performed excellently for the epoxidation of cyclohexene by tertiobutyl hydroperoxide

NenUFAR: Instrument description and science case

International audienceNenuFAR is both a giant extension of the LOFAR and a large standalone instrument in the low-frequency range (10-85 MHz). It was designed in Nançay with national and international collaboration. Antenna radiators were modeled on the LWA antenna design whereas preamplifiers were designed in France. Antennas will be distributed in 96 mini-arrays of 19 dual-polarized elements, densely covering a disk of 400 m in diameter. A few mini-arrays are expected to lie at distances of 2-3 km. A silent control-command system was designed, and the computer dialog with LOFAR defined. Receivers will include the LOFAR backend, a local beamformer and a local correlator. NenuFAR is in construction in Nançay and it was recently granted by the SKA office the official label of SKA pathfinder. Its exploitation will expand the scope of LOFAR scientific studies as well as permit new studies, preparing for SKA science. The NenuFAR concept has many points in common with GURT (the Giant Ukrainian Radio Telescope), with which it shares some technical studies, an its exploitation will benefit from a coordination with UTR-2. We describe the instrument, technical developments and science case