【作者】 张思勃；

【导师】 陈钟荣；

【作者基本信息】 南京信息工程大学 ， 大气遥感科学与技术， 2012， 硕士

【摘要】 随着无线通信技术的发展,在雷达技术中,常常应用各种特定的脉冲波形以满足特定的需求,但在气象雷达中,波形变化较少,本文设计用步进频率信号以解多普勒天气雷达的速度模糊问题,设计了针对步进频率信号的接收机部分,包括射频模块设计和中频回波信号处理平台设计。本文先讲述了多普勒雷达存在速度模糊、距离模糊的原因,以及国内外在多普勒天气雷达解模糊方面的研究。其次介绍了步进频率信号解决多普勒天气雷达模糊问题的原理以及脉冲压缩技术。然后分别设计了实现接收步进频率信号的接收机的各个模块,并仿真了它们的性能,如接收机带宽、驻波比等。接下来设计了基于软件无线电的中频信号处理部分,利用VC++编写混频、滤波、PPP(脉冲对处理)算法、FFT(快速傅立叶变换)算法的程序。然后分析了几种因素,如初相位、A/D截断误差、频率稳定度对信号处理平台的性能与精度的影响。依据对步进频率信号解模糊的理论分析可知,采用步进频率信号可以解多普勒雷达的模糊问题,但对于接收机射频前端的性能指标只在计算机仿真方面进行了检验,还需要实际验证。数字回波信号中频处理平台也需要进一步的利用模拟气象回波信号或真实回波信号进行实际效果检验。更多还原

【Abstract】 With the development of wireless communication technology, sorts of certain pulse waveform are often used to meet specific needs in radar technology. But in the field of weather radar, waveform change less. This paper is designed to adopt step frequency signal to solve the velocity ambiguity problem in Doppler weather radar, devises a receiver part for step frequency signal, including a RF module and intermediate frequency echo signal processing platform.First of all, this paper tells the reasons why velocity and range ambiguity exist in Doppler radar, and the researches on these aspects at both home and abroad. Secondly, we introduce the principle of using step frequency signal to solve Doppler radar ambiguity problem and the pulse compression technique. Meanwhile, various receiver modules are designed respectively to accept step frequency signal, and their properties are simulated, such as receiver bandwidth, VSWR and so on. Furthermore, we excogitate a IF signal processing platform based on software radio, and write procedures of frequency mixing, filtering, PPP(Pulse Pair Processor) algorithm and FFT(Fast Fourier Transform) algorithm via VC++. In addition, we analyze several factors, such as initial phase, A/D truncation error and frequency stability, and their influence on the performance and precision of signal processing platform.On the basis of the theory and analysis about how the step frequency signal achieves the solution of the velocity ambiguity, step frequency signal can solve Doppler radar velocity ambiguity problem. But the performance indexes of the RF front part in receiver are only evaluated by computer simulation, they also need actual verification. Digital echo signal intermediate frequency processing platform also need further inspection for actual effect with simulated meteorological echo signal or real echo signal.更多还原