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Polarimetric inverse synthetic aperture radar
No full textPol-ISAR has proven to be more accurate and more effective than single-channel ISAR when used for target recognition. Given the limited amount of such systems and available data and literature, this is a field that can still benefit from additional study and experimentation to fully exploit its potential. The use of polarimetry involves additional receiving channels in the radar system and therefore it increases the complexity of cost of the overall radar system. This creates a trade-off that must be considered when designing ISAR systems for target recognition. Nevertheless, when size, weight, power and cost constraints are favourable, the benefit of using full polarization is significant both in terms of image quality, by producing better focused images, and in terms of the amount of information (features) that can be exploited to improve target classification performances
Ship detection from SAR images based on CFAR and wavelet transform
No full textIn this paper the authors propose an innovative two-stage technique for ship detection which is applied to sea synthetic aperture radar (SAR) images. This technique is based on the joint use of Wavelet theory, in particular of the two-dimensional Discrete Wavelet Transform (2D-DWT), and the Constant False Alarm Rate (CFAR) processor. Real data acquired from COSMO-SkyMed (CSK) system have been processed to verify the effectiveness of this proposed new technique
X-band full polarized Doppler weather radar return simulation by using propagation-modified ensemble-averaged covariance matrix
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A simulator capable of generating raw time series data for an X-band full polarimetric Doppler weather radar is described in this paper. Mie scattering and propagation effects are taken into account. Common polarimetric radar observables, relative to rain, hail, graupel and snow hydrometeors, were estimated from the simulated time series. The simulation method was validated by comparing the estimated radar observables with real measurements and other simulations that can be found in the existing literature, showing strong agreement
Polarimetric Avionic Weather Radar for Increasing Flight Safety and Efficiency
No full textCurrent avionic weather radars cannot give accurate information about the weather hazards. Pilots avoid the potentially dangerous area with a greater detour, but only thirty percent of “red echo” radar returns represent actually a threat. These detours involve a longer trajectory and a greater impact on the environment. Instead, a polarimetric radar, which can discriminate for instance between rain and hail, can enhance pilot situational awareness and support trajectory optimization. In the framework of KLEAN project funded by CLEANSKY Joint Technology Initiative, a customized knowledge-based Electronic Flight Bag (EFB) was developed. This EFB, other than being capable to show the map, the flight trajectory and information about surrounding environment, it also implements a polarimetric radar data processor aimed to the assessment of the risk level of the phenomena encountered en route
Capabilities and potential of an avionic polarimetric weather radar simulator
No full textIn this paper, the potential of an avionic polarimetric weather radar is shown. The simulator used for such a purpose is a statistical simulator capable of reproducing complex signals as those gathered by an onboard radar, along with polarimetric and Doppler observables. The simulator, developed in the framework of the CleanSky European program, can be an useful tool to evaluate the radar prototypes that in a near future will be mounted on real aircrafts to enhance pilots' environmental awareness, which is declared as a major CleanSky objective
Analysis of X-band weather polarimetric radar simulator for avionic purposes
No full textThe improvement of the essential aircraft equipment used by pilots has a very important role in safety enhancement. In this context polarimetric weather Doppler radars could offer a valuable aid in improving detection and classification of hydrometeors, helping pilots to take the more efficient trajectory, balancing risk level and unnecessary detours. In this work an analysis of a polarimetric radar signal simulator developed by the RaSS team is presented
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Software Module for SAR/ISAR Data Analysis
No full textThe present document focuses on two main topics
- the detection of humans occluded by thin opaque layers
- task based configuration optimization of the SAR system.
In particular, the purpose of the document is to show how the detection of humans can be made within a radar image and how the target at the output of the detection step can be analysed in order to identify the targets of major interest in the image.
In addition, the second part of the document focuses on the cognitive module in order to describe the way the system parameters are updated according to the scenario at hand.
The activities described in this document refer to the tasks T.4.1.3 e T.4.1.4 of the DoW. Although D.4.3 is a DEMO and not a REPORT, the authors have found useful to write a report too so as to describe the implemented techniques and algorithms. The algorithms presented in this document have been implemented and evidence of it is shown in the result analysis conducted, when possible, by using real data. However, such algorithms still need to be integrated among them in a unique algorithm which in our intention should be as automatic as possible. This activity concerns T.5.1 and will be reported in Deliverable D.5.1
Settings for SAR Reconfigurable Approach
No full textCAESARIS project has been conceived to answer the need of the EU Internal Security Strategy to strengthen the border security management for immigration control and fight against cross-border crime.
To answer this need, CAESARIS project aims to develop an integrated security and search-and-rescue 24/7 all-weather airborne system to detect illegal border crossing with special focus on people visible and conceived under opaque layers. To provide 24/7 all weather night/day capability, CAESARIS system makes use of EO and radar systems.
Market products and R&D projects can be found that provide examples of homeland security systems including airborne remote sensing technologies [1][2][3][4]. However, none of them provides an integrated system able to reconfigure itself in a context aware manner. Some theoretical studies have been carried out recently mainly from Haykin [6] and Guerci [5] that introduce the concept of cognitive systems and knowledge-based systems.
The context-aware self-configuration capability offers the possibility to choose the best sensors configuration to optimize the detection and the imaging performance. In fact, according to the targets of interest, the platform motions, the land-type and the presence of opaque layers, an optimal set of parameters can be identified that maximises the system's performance.
With special focus on the radar system, and specifically on SAR system, this document aims to identify the reconfigurable parameters and the factors that affect their optimization
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