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Detection and localization in urban environments is a very recent radar problem. In this paper, we investigate the possibility of detecting and locating targets not in direct line of sight (NLOS) areas with a single portable radar by exploiting multipath returns. We propose two algorithms, which handle the information provided by multipath returns in different ways to detect and estimate the NLOS target position. We also present an original method to select the number of paths to take into account in the algorithms in order to maximize detection probabilities. Numerical results show good efficiency of the proposed algorithms for problems of both detection and localization. We show that applying these algorithms improves detection performance compared to a classic matched filter in a typical urban scenario. Experimental results on a real dataset allow us to validate our multipath model in urban environments, and in particular to show that it is possible to retrieve the target location even with rough knowledge of the scene geometry. [ABSTRACT FROM AUTHOR]

We analyze the coexistence between the L-band Digital Aeronautical Communication System?option 2 (L-DACS2), which is a preselected candidate to support future continental communications, and the distance measuring equipment (DME), which is an L-band radionavigation system in use for decades, now implemented in all aircrafts. We focus on the impact of L-DACS2 interference on the DME performance under the cosite scenario, where both equipment are located in the same aircraft. After a brief presentation of both systems, we study this critical scenario (from the system coexistence viewpoint), by proposing a new approach (different from classical frequency-domain analysis) that takes into account system dynamics and their technology characteristics. Based on various implementation methodologies, we show in the last part of the paper, the effect of some parameters on the coexistence between the on-board L-DACS2 transmitter and the on-board DME receiver. [ABSTRACT FROM AUTHOR]

We present in this survey new technologies proposed for the evolution of the aeronautical communication infrastructure. Motivated by studies that estimate the growth of air traffic flow, it was decided to develop a future communication infrastructure (FCI) adapted to the future aeronautical scenario. The FCI development involves researchers, industrials, and aeronautical authorities from many countries around the world, and started in 2004. The L-band Digital Aeronautical Communication System (L-DACS) is the part of the FCI that will be in charge of continental communication. The L-DACS is being developed in Europe since 2007 and two candidates were preselected: L-DACS1 and L-DACS2. In this paper, we first describe the motivations of the FCI. We then give an overview of its development activities from 2004 to 2009. After that, we provide some insights about both preselected L-DACS candidates, at their physical and medium access layers. Finally, we address the challenges on the development of the FCI/L-DACS. [ABSTRACT FROM PUBLISHER]