摘要
为研究短波信道多普勒功率谱密度,将电离层的运动假设为正规层与不均匀团块两种不同的运动,推导出了多普勒频移的表达式;在忽略电子密度随时间变化和地磁场影响的情况下,推导出了多普勒频移的一种概率密度函数表达式;在假设接收天线是圆对称的条件下,推导出了信号散射分量的多普勒功率谱密度函数,结果表明,功率谱密度的形状为混合高斯形;采用寻找误差序列标准差最小值的方法对实验所得数据多普勒功率谱密度的形状进行了混合高斯形状拟合,拟合结果表明了理论推导的正确性.
In order to study HF channel Doppler power spectral density（PSD）, the ionospheric movements were assumed to be two different motions of the regular layers and the irregularities, based on which an expression of Doppler shift was de-duced. Then the probability density function（PDF）of Doppler shift was derived, which left electron density variance with time and the effect of the variance of geo- magnetic field with time out of account. On condition that the receiving antenna is omni-direction, the PSD function of the scattering signal component was obtained, which shows the PSD is of a mixture Gaussian shape. The mixture Gaussian shape curve fitting of Doppler PSDs of the data acquired in experiment were made by looking out the minimum standard deviation of error sequence and the fitting results indicate the validity of the theoretical deduction.
出处
《电波科学学报》
EI
CSCD
北大核心
2013年第4期775-781,793,共8页
Chinese Journal of Radio Science
关键词
短波信道
电离层
多普勒频移
功率谱密度
概率密度
HF channel
ionosphere
Doppler shift
power spectral density
proba-bility density
