نتایج جستجو برای: doppler radar

تعداد نتایج: 80632  

2006
MIN DENG GERALD G. MACE

The first three moments of the millimeter-wavelength radar Doppler spectrum provide valuable information regarding both cloud properties and air motion. An algorithm using these Doppler radar moments is developed to retrieve cirrus microphysical properties and the mean air vertical motion and their errors. The observed Doppler spectrum results from the convolution of a quiet-air radar reflectiv...

2005
Bertrand Chapron Fabrice Collard Fabrice Ardhuin

[1] The median Doppler shift of radar echoes is analyzed in measurements by ENVISAT’s Advanced Synthetic Aperture Radar (ASAR) over the ocean. This Doppler centroid differs from a predicted signal based on the predicted motion of the satellite and Earth. This anomaly, converted to a surface Doppler velocity UD, appears to be of geophysical origin. Two wide-swath images over the Gulf Stream arou...

Journal: :Optics letters 1995
A K Andrews R S Hudson D Psaltis

During the past five years, delay-Doppler radar has become the primary technique for studying the structure of Earth-crossing asteroids. None of these objects has yet been visited by spacecraft, so ground-truth test cases are lacking. A laboratory system is described that provides optical-radar images at 0.1-mm resolution. These data are analogous to the highest-resolution asteroid radar images...

Journal: :Journal of neurology, neurosurgery, and psychiatry 1986
R A Roos E A Van der Velde O J Buruma F A de Wolff

Ten patients with tardive dyskinesia were treated with tiapride at an increasing dosage to establish the dose-concentration relationship and the dose-effect relationship. The effect was scored with the Abnormal Involuntary Movement Scale (AIMS) and the Doppler-radar method. The intra individual dosage-serum concentration correlation coefficients varied from 0.86 to 0.99 and the slopes of the in...

2007
Sandy Dance

In this paper we discuss our work with agent-based image processing systems, and describe work in progress applying these concepts to meteorological data sets, especially radar. Radar is particularly amenable to image processing, being structured in 2, 3 or 4 dimensions, and conveying reflectivity or velocity information. We discuss a number of existing meteorological radar image processing sys...

2013
Wen-Qin Wang

It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms shoul...

2012
M. Maahn

The Micro Rain Radar 2 (MRR) is a compact Frequency Modulated Continuous Wave (FMCW) system that operates at 24 GHz. The MRR is a low-cost, portable radar system that requires minimum supervision in the field. As such, the MRR is a frequently used radar system for conducting precipitation research. Current MRR drawbacks are the lack of a sophisticated post-processing algorithm to improve its se...

2003
S. E. Milan M. Lester N. Sato

Multi-frequency observations of E-region coherent backscatter from decametre waves reveal that auroral echoes tend to comprise two spectral components superimposed, one at low Doppler shifts, below 250 m s−1, and the other Doppler shifted to near the ion-acoustic speed or above, up to 800 m s−1. The low Doppler shift component occurs at all look directions; Doppler shifts near the ion acoustic ...

2013
Allen Zhao

The final goal of this project is to provide the US Navy with an increased capability of using Doppler radar observations in the detection and prediction of hazardous weather events that usually have a strong randomness in nature and affect the Navy operations, especially over oceans and in remote areas. By developing a high-resolution data assimilation capability that can effectively assimilat...

2017
Qingjun Zhang Feng Xiao Zegang Ding Meng Ke Tao Zeng

Synthetic aperture radar (SAR) sliding spotlight work mode can achieve high resolutions and wide swath (HRWS) simultaneously by steering the radar antenna beam. This paper aims to obtain well focused images using sliding spotlight mode with the Chinese Gaofen-3 SAR sensor. We proposed an integrated imaging scheme with sliding spotlight echoes. In the imaging scheme, the two-step approach is app...

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