机载前视风切变雷达是飞机进行风切变探测和预警的重要工具. 为了设计一种可输出风切变雷达仿真信号的风切变信号发生器, 利用快速傅立叶变换( FFT) 法分析某型机载前视风切变雷达的回
波信号, 分别用频谱估计法和经典功率谱估计法两种方法估计了雷达回波信号的多普勒频移, 比较两种方法的优劣, 进而选择经典功率谱估计法计算出风场的径向风速分布. 建立均一化静止对称的风场模型
仿真了风切变雷达的回波信号, 从而设计出可输出风切变雷达仿真信号的风切变信号发生器, 可满足机载气象雷达航空部附件维护和维修时对便携性和灵活性的需求.
Abstract
Airborne weather radar is important for detecting low altitude wind shear which is a major contributing factor in many airline crashes. Numerous accidents have occurred that were attributed to low?altitude wind shear,
Research on the wind shear detection for airborne forward looking wind shear weather radar has important application value. Up to now, several methods have been proposed for wind shear signal processing, such as fast
Fourier transform, pulse pair processing and so on. In industry, the most widely used method is fast fourier transform, so fast fourier transform is the chosen method for analyzing airborne forward looking wind shear radar
simulated echo data. T he spectrum estimation method and the classical power spectrum estimation method are used to estimate the Doppler frequency. The results obtained by these two methods are compared, and the classical power
spectrum estimation method is better because its result contains more spectral information. The classical power spectrum estimation method is chosen to calculate the radial velocity of the wind field. According to this method, the
weather radar simulated echo data is analyzed, the potential danger of wind shear can be well reflected in the result, and the radial velocity field is estimated. The result shows that the average radial velocity experienced a dramatic
change, the slope of the average radial velocity curve can be used to measure the danger of wind shear. Thehomogenization static symmetric wind field model is established for simulating the wind shear radar echo data. The
model can reflect the characteristics of the radial velocity in wind shear field. According to the model, a wind shear radar signal generator is designed, based on the simulated radar echo data which is easy to modify the parameters on
demand. The generator can load the simulated radar echo data from personal computer, and output signals to the radio frequency( RF) simulator. The generator can meet the airborne weather radar,s requirements for portability and flexibility.
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[ 1 ] Sinclair P C, Kuhn P M . Aircraft low altitude wind shear detection and warning system. Journal of Applied Meteorology, 1991, 30: 3~ 16.
[ 2 ] Wu R S. Preface some problems of typhoon study. Journal of Nanjing University ( Natural Sciences) , 2007, 43( 6) : 567~ 571. (伍荣生. 前言台风研究中的一些科学问题. 南京大学学报( 自然科学), 2007, 43(6): 567~ 571) .
[ 3 ] Luo W C. Studying the signal processing technology of airborne forward?looking windshear weather radar. Northwestern Polytechnical
University, 2001, 43~ 49. ( 骆文成. 机载前视风切变气象雷达信号处理技术研究. 西北工业大学, 2001, 43~ 49).
[ 4 ] Jonggil L. Doppler moment estimation in a weather radar. International Journal of Electronics, 2002, 89(7): 583~ 592.
[ 5 ] Aalfs D D, Baxa E G, Bracalente E M. Signal processing aspects of wind shear detection. Microwave Journal, 1993, 36( 9) : 76~ 96.
[ 6 ] Fang D X, Liu G Q, Dong X N, et al. The application of region growing in the analysis on velocity field of the weather Doppler radar. Journal of Nanjing University ( Natural Sciences),
2007, 43( 1) : 102~ 110. ( 方德贤, 刘国庆, 董新宁等. 区域生长法在多普勒天气雷达速度场分析中的应用. 南京大学学报( 自然科学), 2007, 43( 1) : 102~ 110) .
[ 7 ] Ma Z H. Weather radar echo information theory. Beijing: Science Press, 1986: 96~ 142. (马振骅. 气象雷达回波信息原理. 北京: 科学出版社, 1986: 96~ 142).
[ 8 ] Wang L J, Kareem A. Modeling and simulation of transient winds in downbursts/ hurricanes. Proceedings of 10 th American Conference on Wind Engineering, Baton Rouge, 2005: 1~ 12.
[ 9 ] Vicroy D D. Assessment of microburst models for downdraft estimation. Journal of Aircraft, 1992, 29(6): 1043~ 1048.
[ 10] Galati G, Pavan G, Computer simulation of weather radar signals. Simulation Practice and Theory, 1995, 3: 17~ 44.
[ 11] Bray R S. A method for three -dimensional modeling of wind shear environments for flight simulator applications. NASA TM?85969, 1984.
[ 12] Lagha M, Bensebti M . Performances comparison of pulse pair and 2-step prediction algorithms for the Doppler spectrum estimation. Multidimensional Systems and Signal Processing, 2008, 19(2): 257~ 265.
[ 13] Zrni D S, Burgess D W, Hennington L D. Automatic detection of mesocyclonic shear with Doppler radar. Journal of Atmospheric and Oceanic T echnology, 1985, 2( 4) : 425~ 438.
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
基金
毫米波国家重点实验室( K200819)
{{custom_fund}}