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The Method to Determine the Noise Power of Wind Profile Radar
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摘要: 风廓线雷达以测风为主要目的设计，没有充分考虑强度的定量测量。如果能够实现强度定量测量将大大扩展风廓线雷达的应用范围。首要的扩展应用就是可以获取雨滴谱分布、解决降水定量测量准确性问题。若实现强度定量测量，需要解决的一个关键技术问题是如何由其功率谱数据准确计算噪声功率。该文根据风廓线雷达功率谱估计方法、依据噪声频域统计特性，提出了一种计算风廓线雷达功率谱噪声功率的方法，并利用风廓线雷达实测功率谱数据进行检验。检验结果表明：即便在有降水或存在地物时，该方法仍可以准确、快速分辨出噪声功率谱, 且客观有效。Abstract: The main intention of designing wind profile radar is to obtain wind information of the atmosphere. However, it does not take full account of the function of intensity measurement. The applications of the wind profile radar will be greatly expanded, if the function of intensity measurement is implemented. A very important extension is to measure the process of precipitation and to get raindrop size distribution which can fundamentally improve the quality of quantitative measurement of precipitation. To achieve the intensity quantitative measurement, the key technical issue that must be solved is how to calculate the noise power accurately from power spectral density. Based on the power spectral density estimation method of wind profile radar adopted and the noise frequency domain statistical characteristics, a method to calculate noise power of wind profile radar is proposed and the validation of the method is done by using of wind profile radar measured power spectral density data. Results show that the method performs well. The power spectral density of noise can be separated accurately even in complex echo situation such as precipitation or strong surface clutter. The method is established on solid theory foundation. The calculation of noise power is accurately, quickly and efficiently, which looks forward to becoming a practical technology of wind profile radar.
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Key words:
- wind profile radar;
- power spectrum;
- noise power
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图 1 降水天气时确定噪声功率密度门限实例
(a) 实测功率谱，(b) 噪声功率谱，(c) 判别因子R随迭代次数变化
Fig. 1 Example of determining the threshold of noise power density on precipitation weather
(a) curve of power spectral density, (b) curve of noise power spectral density, (c) variation of discriminate factor R with iterations
图 2 强地物信号时确定噪声功率密度门限实例
(a) 实测功率谱，(b) 噪声功率谱，(c) 判别因子R随迭代次数变化
Fig. 2 Example of determining the threshold of noise power density in clutter environment
(a) curve of power spectral density, (b) curve of noise power spectral density, (c) variation of discriminate factor R with iterations
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