【作者】 张毅；

【导师】 许录平； 李春化；

【作者基本信息】 西安电子科技大学 ， 电子与通信工程， 2009， 硕士

【摘要】 多普勒气象雷达能够利用气象目标的回波信息探测雨、雪及冰雹等天气状况的位置和强度分布情况。气象目标的动态范围通常大于80dB,在强对流天气条件下的平均速度会超过30m／s,因此要求气象雷达具有较大的测距和测速范围,否则会出现距离和速度模糊现象。本课题针对某单位气象雷达的研制要求,需要对气象雷达解距离速度模糊的方法进行研究。本文首先对气象雷达的发展概况、气象目标探测的基本原理及距离速度模糊问题进行了简要介绍,并在此基础上对气象目标的时频特性、气象回波信号谱矩估计的时域和频域方法以及气象信号的模型和相关性进行了讨论。其次在重点参差重复频率解模糊方法的基础上给出了速度估计公式以及该公式的限制条件和修正方法。仿真结果表明,修正后的测速公式能够有效减小最大不模糊速度范围内的速度估计误差。随后在对相位编码解模糊方法进行讨论的基础上研究了一种相位编码序列和相应的频域处理方法,仿真结果表明该序列能够更好地从重叠回波中恢复出期望的气象回波。最后结合某项目的研制要求,讨论了使用批次处理法与参差脉冲重复频率法相结合解距离速度模糊的方法及两个重要参数(参差比和脉冲重复频率)的选择原则并对实际选取的参数进行了仿真。本课题的研究取得了良好的效果,为在引进的信号处理器上验证不同解模糊方法所适用的气象条件打下了良好的基础。更多还原

【Abstract】 Doppler weather radars can detect the location and intensity distribution of rain、snow and hailstone according to the information of weather targets echo. The dynamic range of weather targets can exceed 80dB, and the mean velocity of strong convection weather is about 30m/s, so the weather radars are required with the large range-velocity range, otherwise will appear range-velocity ambiguity. This thesis needs to study on range-velocity ambiguity resolution contrapose to the demand of weather radars in one institute.Firstly, we introduce the developing of the weather radar、basic principle of weather targets detect and the problem of range-velocity ambiguity. Then, we discuss the time and frequency domain properties of weather radar echo, methods of weather radar echo Spectral Moments estimators in the time and frequency domain, weather radar echo simulation methods and relativity.Secondly, we introduce the ambiguity resolution of staggered repetition frequency. Emphases study on staggered repetition frequency ambiguity resolution, gives the formula of velocity estimate and restricts condition and method of modifity. The simulation results shows that the modified formula can reduce the error in the range of the most non-ambiguity of velocity.Subsequently, we studied on a phase-coded sequence and the process method in frequency domain base on the discussing of phase-coded ambiguity resolution, the simulation results shows that this sequence can resume the expectation weather echo from recovery echoes.Finally, we discuss the methods combine the batch mode and staggered repetition frequency for range-velocity ambiguity resolution according to the demand of one project, and discussed the choice fundamental of two significant parameters (staggered ratio and PRF). Simulated the selected parameter.This thesis lays the favorable foundation for the validation of different ambiguity resolutions suited weather condition in the fetched signal process unit.更多还原