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应用双偏振天气雷达探测天气信号的方法备受国内外气象科技领域人员的关注。目前,双偏振天气雷达的双通道同时收发体制是由功分器将发射通道的能量等分为水平和垂直两路发射通道,其结果会使每个通道发射能量减半,又由于接收机产生的噪音能量是不变的,必然引起回波信噪比减弱,减弱值约为3 d B。为了避免3 d B损失带来的不利影响,需改进双偏振雷达的探测性能。将双偏振雷达回波信号中的双通道信号间的互相关信息、单通道信号自身的信相关信息及每个信号自身的能量信息求和,再将结果与预先设置好的阈值进行比较。如果结果大于这个阈值,就认为这个信号是有效信号,否则就认为它是噪声并被滤除。文中利用X波段双偏振天气雷达数据,对比了引入互相关算法前后的探测效果,证明利用双通道信号互相关、单通道自相关及信号能量自身求和判断信号是否存在的效果较好;介绍了中值滤波技术,并利用中值滤波技术去除了天气回波中的点杂波,提高了双偏振天气雷达的探测性能。
The application of dual polarized weather radar to detect the weather signal has attracted much attention from people in the field of meteorology at home and abroad. At present, the dual-channel simultaneous transmission and reception system of the dual-polarization weather radar divides the energy of the transmission channel into two horizontal and vertical transmission channels by the power splitter. As a result, the transmission energy of each channel is reduced by half and the receiver generates The noise energy is constant, inevitably causing the echo signal to noise ratio weakened, the weakened value of about 3 d. In order to avoid the adverse effect of 3 dB loss, the detection performance of dual polarization radar needs to be improved. The cross-correlation information between two channels of dual-polarized radar echo signal, the information about the single channel signal itself and the energy information of each signal are summed, and then the result is compared with a preset threshold. If the result is greater than this threshold, the signal is considered a valid signal, otherwise it is considered noise and filtered out. In this paper, the X-band dual-polarization weather radar data are used to compare the detection results before and after the introduction of the cross-correlation algorithm, which proves that the signal is better than the sum of two-channel signal correlation, single-channel autocorrelation and signal energy self-summation Median filter technology, and the use of median filter technology to remove clutter in the weather echo, improve the dual polarization weather radar detection performance.