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http://dx.doi.org/10.14744/nci.2024.30670 | DOI Listing |
North Clin Istanb
June 2025
Department of Radiology, Canakkale Onsekiz Mart University Faculty of Medicine, Canakkale, Turkiye.
Sci Rep
August 2025
School of Electronic Engineering, Naval University of Engineering, Wuhan, 430000, China.
Passive radar (PR) relies on receiving signals reflected from targets by other existing noncooperative radiation sources, which are broadly divided into ground- and space-based categories, to achieve target detection and tracking. In the context of space-based PR, this paper proposes a PR using the Iridium satellite signal, which is a low-orbit satellite communication signal with global coverage. With an improved detection range and accredited ambiguity function, a PR using the Iridium satellite signal can address the issues of limited terrestrial coverage for ground-based PR and insufficient receiving power for medium- to high-orbit space-based PR.
View Article and Find Full Text PDFAccurately measuring wind fields is crucial for weather forecasting, climate and meteorological research, aeronautical flights, and wind resource exploitation. Spaceborne Doppler wind lidar has become an important instrument for observing the vertical profile of the global wind field, with the successful operation of Aeolus. The third generation of FengYun polar-orbiting meteorological satellites is initially designed to develop a dual-system Doppler wind measurement lidar technology program that integrates direct and coherent detection lidar, making full use of the observational advantages of the two methods to detect the global wind field with high resolution.
View Article and Find Full Text PDFSingle-frequency laser beams, especially when located in eye-safe bands, provide significant insights for Doppler metrology exploiting lidar technology. To extend these prospects further, we push forward the advancement of such lasers into the orbital angular momentum (OAM) manipulation domain. The intra-cavity generation of single-frequency degenerate modes with opposite OAM in eye-safe band is experimentally demonstrated in a unidirectional ring resonator with a spot-defect filter (SDF).
View Article and Find Full Text PDFThe rotational Doppler effect (RDE) of structured light carrying orbital angular momentum (OAM) has attracted widespread interest in optical sensors and OAM spectrum detection. However, the motion parameters of spinning objects are the main focus of the RDE-based research, and other equally significant attitude properties have rarely been considered. In the experiments, we noticed an intriguing phenomenon: the rotational Doppler spectral distribution is affected by both the ellipticity of the elliptical optical vortex (EOV) and the tilt angle between the rotational axis and the optical axis.
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