Application of track-before-detect techniques in GNSS-based passive radar for maritime surveillance

GNSS-based passive radar has been recently proved able to enable moving target detection in maritime surveillance applications. The main restriction lies in the low Equivalent Isotropic Radiated Power (EIRP) level of navigation satellites. Extending the integration times with proper target motion compensation has been shown to be a viable solution to improve ship detectability, but this involves computational complexity and increasing sensitivity to motion model mismatches. In this work, we consider the application of a Track-Before-Detect (TBD) method to considerably increase the integration time (and therefore the detection capability) at the same time keeping the computational complexity affordable by practical systems. Dynamic programming TBD algorithms have been specialized for the considered framework and tested against experimental dataset. The obtained results show the effectiveness of this approach to improve the detection capability of the system despite the restricted power budget

Joint detection and localization of vessels at sea with a GNSS-Based multistatic radar

This paper addresses the exploitation of global navigation satellite systems as opportunistic sources for the joint detection and localization of vessels at sea in a passive multistatic radar system. A single receiver mounted on a proper platform (e.g., a moored buoy) can collect the signals emitted by multiple navigation satellites and reflected from ship targets of interest. This paper puts forward a single-stage approach to jointly detect and localize the ship targets by making use of long integration times (tens of seconds) and properly exploiting the spatial diversity offered by such a configuration. A proper strategy is defined to form a long-time and multistatic range and Doppler (RD) map, where the total target power can be reinforced with respect to, in turn, the case in which the RD map is obtained over a short dwell and the case in which a single transmitter is employed. The exploitation of both the long integration time and the multiple transmitters can greatly enhance the performance of the system, allowing counteracting the low-power budget provided by the considered sources representing the main bottleneck of this technology. Moreover, the proposed single-stage approach can reach superior detection performance than a conventional two-stage process where peripheral decisions are taken at each bistatic link and subsequently the localization is achieved by multilateration methods. Theoretical and simulated performance analysis is proposed and also validated by means of experimental results considering Galileo transmitters and different types of targets of opportunity in different scenarios. Obtained results prove the effectiveness of the proposed method to provide detection and localization of ship targets of interest

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

Identificação de fontes de resistência à ferrugem Polissora em milho e desenvolvimento de população de mapeamento.

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Construção de um mapa genético a partir de uma população F2 derivada do cruzamento entre Coffea arabica e C. canephora e Sua utilidade para qualidade de bebida.

Mapas genéticos com base em marcadores moleculares têm sido desenvolvidos em grande número de plantas como uma estratégia eficaz para seleção assistida pelo marcador. No presente estudo, marcadores AFLP e SSR foram utilizados para construção de um mapa genético em uma população F2 criada a partir da autofecundação do híbrido F1 do cruzamento entre Coffea arabica e Coffea canephora. Foram identificados 349 marcadores AFLP e 50 alelos SSR segregantes em 90 plantas F2. Para construção do mapa, apenas marcas em dose única e segregação 3:1 no F2 foram consideradas (248 marcadores AFLP e SSR 27 alelos, ou 68,9% dos marcadores polimórficos). Cento e sessenta e nove marcadores foram mapeados (155 AFLP e 14 SSR). Trinta e sete grupos ligação correspondentes a um total de 1011 cM foram obtidos, com uma distância média entre as marcas de 5,98 cm e 4,6 marcadores por grupo de ligação. Quarenta e seis marcadores associados a características agronômicas de interesse foram encontrados, dos quais, dezenove foram associados com teor de açúcar, oito de cafeína, oito para CGA, um para a cafeína e CGA e dez para a produção total por planta. A análise baseada em marcadores de dose única permitiu obter informação de QTL putativo associado à qualidade de bebida do café e produtividade. Marcadores adicionais serão incluídos a este trabalho para maior cobertura do genoma café

Radiotherapy prolongs the survival of advanced non-smallcell lung cancer patients undergone to an immune-modulating treatment with dose-fractioned cisplatin and metronomic etoposide and bevacizumab (mPEBev)

Radiotherapy (RT), together with a direct cytolytic effect on tumor tissue, also elicits systemic immunological events, which sometimes result in the regression of distant metastases (abscopal effect). We have shown the safety and anti-tumor activity of a novel metronomic chemotherapy (mCH) regimen with dose-fractioned cisplatin, oral etoposide and bevacizumab, a mAb against the vasculo-endothelial-growthfactor (mPEBev regimen), in metastatic non-small-cell-lung cancer (mNSCLC). This regimen, designed on the results of translational studies, showed immune-modulating effects that could trigger and empower the immunological effects associated with tumor irradiation. In order to assess this, we carried out a retrospective analysis in a subset of 69 consecutive patients who received the mPEBev regimen within the BEVA2007 trial. Forty-five of these patients, also received palliative RT of one or more metastatic sites. Statistical analysis (a Log-rank test) revealed a much longer median survival in the group of patients who received RT [mCH vs mCH + RT: 12.1 +/-2.5 (95%CI 3.35-8.6) vs 22.12 +/-4.3 (95%CI 11.9-26.087) months; P=0.015] with no difference in progression-free survival. In particular, their survival correlated with the mPEBev regimen ability to induce the percentage of activated dendritic cells (DCs) (CD3-CD11b+CD15-CD83+CD80+) [Fold to baseline value (FBV) 641 vs > 1: 4+/-5.389 (95%CI,0-14.56) vs 56+/-23.05 (95%CI,10.8-101.2) months; P:0.049)] and central-memory-T-cells (CD3+CD8+CD45RA-CCR7+) [FBV 641 vs > 1: 8+/-5.96 (95%CI,0-19.68) vs 31+/-12.3 (95%CI,6.94-55.1) months; P:0.045]