274 research outputs found
Target motion estimation via a multistatic FSR
The focus of this paper is on the estimation of the kinematic parameters of moving targets
via a MIMO Forward Scatter Radar (FSR) system. A sub-optimum estimation technique is considered
that exploits the information concerning the time instants at which the target crosses the individual
baselines to retrieve the motion parameters. The accuracy of such technique is firstly investigated
from a theoretical point of view and then the effectiveness of the proposed approach is demonstrated
by applying it to live MIMO FSR data. Shown results prove the practical applicability of the proposed
technique
Experimental demonstration of ship target detection in GNSS-based passive radar combining target motion compensation and track-before-detect strategies
This work discusses methods and experimental results on passive radar detection of moving ships using navigation satellites as transmitters of opportunity. The reported study highlights as the adoption of proper strategies combining target motion compensation and track-before-detect methods to achieve long time integration can be fruitfully exploited in GNSS-based passive radar for the detection of maritime targets. The proposed detection strategy reduces the sensitivity of long-time integration methods to the adopted motion models and can save the computational complexity, making it appealing for real-time implementations. Experimental results obtained in three different scenarios (port operations, navigation in open area, and river shipping) comprising maritime targets belonging to different classes show as this combined approach can be employed with success in several operative scenarios of practical interest for this technology
Planar Thinned Arrays: Optimization and Subarray Based Adaptive Processing
A new approach is presented for the optimized design of a planar thinned array; the proposed strategy works with single antenna elements or with small sets of different subarray types, properly located on a planar surface. The optimization approach is based on the maximization of an objective function accounting for side lobe level and considering a fixed number of active elements/subarrays. The proposed technique is suitable for different shapes of the desired output array, allowing the achievement of the desired directivity properties on the corresponding antenna pattern. The use of subarrays with a limited number of different shapes is relevant for industrial production, which would benefit from reduced design and manufacturing costs. The resulting modularity allows scalable antenna designs for different applications. Moreover, subarrays can be arranged in a set of subapertures, each connected to an independent receiving channel. Therefore, adaptive processing techniques could be applied to cope with and mitigate clutter echoes and external electromagnetic interferences. The performance of adaptive techniques with subapertures taken from the optimized thinned array is evaluated against assigned clutter and jamming scenarios and compared to the performance achievable considering a subarray based filled array with the same number of active elements
Effect of AlN Seed Layer on Crystallographic Characterization of Piezoelectric AlN
Ultrathin aluminum nitride (AlN) films are of great interest for integration
into nanoelectromechanical systems for actuation and sensing. Given the direct
relationship between crystallographic texture and piezoelectric response, x-ray
diffraction has become an important metrology step. However, signals from
layers deposited below the piezoelectric (PZE) AlN thin film may skew the
crystallographic analysis and give misleading results. In this work, we compare
the use of a Ti or AlN seed layer on the crystallographic quality of PZE AlN.
We also analyze the influence of several AlN seed layer thicknesses on the
rocking curve FWHM of PZE AlN and demonstrate an larger effect of the AlN seed
layer on the {\theta}-2{\theta} AlN crystallographic peak for increasing
AlN seed layer thickness.Comment: 16 pages, 4 figures, 1 tabl
Identificação de fontes de resistência à ferrugem Polissora em milho e desenvolvimento de população de mapeamento.
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