风廓线雷达回波强度和速度标定问题研究

Research on Calibration of Echo Intensity and Velocity for Wind-Profiling Radar

文章讨论了风廓线雷达标定系统中的两个问题。首先,在风廓线雷达回波强度标定原理的基础上,依据雷达气象方程,分析了发射功率变化和接收机增益变化对回波强度测量精度的影响,提出了通过实时测量每个脉冲重复周期内发射采样脉冲功率和回波功率在数字中频接收机的输出值,改善回波强度测量精度的方法。其次,在风廓线雷达速度标定原理的基础上,分析了速度标定中因1/Q信号的幅度、相位不平衡造成的镜像谱分量,提出了一种基于信号时域统计特性的订正方法,并利用I/Q信号数学模型进行了仿真实验,结果表明,该方法可以有效抑制I/Q信号幅相不平衡产生的镜像谱分量。

This paper discusses two problems on calibration of wind-profiling radar.Firstly,based on the calibration principle of echo intensity,it analyzes the effect of variations in transmitted power and receiver gain on measurement accuracy of echo intensity using weather radar equation.In addition,it puts forward a method to improve measurement accuracy of echo intensity by measuring sampled transmitted pulse and backscattered power at the output of digital receiver during each pulse repetition time.Secondly,according to calibration principle of velocity,it analyzes the image spectral component caused by imbalance in amplitude and phase of I/Q signals in velocity calibration.Moreover,it presents a correction method based on statistical characteristics of time domain signals.What＇s more,simulation experiment is conducted using mathematic models for I/Q signals.And the result shows that this method can suppress the image spectral component effectively.