摘要
雷达回波信号谱矩的计算,通常都是采用"客观噪声电平切割法"作噪声电平切割,再对整个谱进行积分的方法。但是在风廓线雷达研制时发现,当回波信号比较强时,这种方法计算结果较好,而信号弱时,确定的噪声电平偏高,使计算出的信噪比偏低,谱宽偏差较大,而风廓线雷达实际测量时,大部分情况下信号都很微弱,影响了该方法的适用性。为此,提出了用"分段平均法"确定噪声电平,然后只对信号谱峰包络部分进行积分计算的方法,数值模拟试验结果表明:在高信噪比时,两者的计算误差相当。而当信噪比小于5 dB以下时,采用"分段平均法"和局部谱峰包络积分的计算结果明显要好一些。
To calculate the moments in Doppler radar echo spectra,the objective method is used firstly to cut the noise level,and then the spectrum moment of radar echo is obtained from the integral of the whole spectra.When the wind profiler is manufactured,this method is just suitable for a strong echo.In this situation,it can get a good effect.But when the radar echo is weak,this method will cut too high noise level,and then cause too lower signal-to-noise ratio and too big spectral width.So this method is not better to be used in wind profiler because the radar echo is usually weak.To solve this problem,a method is proposed which uses least average value as noise level.The value is computed from the respective spectra in 4 or 8 sections.The result of simulation test show that the two methods can get a equivalent precision when the signal-to-noise ratio is high.But when signal-to-noise ratio is lower than 5dB,the new method will get a better effect.
出处
《现代雷达》
CSCD
北大核心
2010年第10期37-41,共5页
Modern Radar
基金
江苏省气象局北极阁基金资助项目(BJG200802)
国家自然科学基金资助项目(41005018)
关键词
风廓线雷达
谱宽
模拟试验
wind profiler
spectrum width
simulation test
