Numerical research on effects upon precipitation forecast of doppler - radar estimated precipitation and retrieved wind field under different model initial schemes 多普勒雷达估算降水和反演风在不同初值方案下对降水预报影响的数值研究
For the case of a doppler radar , the faster the raindrops move towards the radar , the higher will be the frequency i . e . pitch of the microwave reflected from raindrops fig . 1 多普勒雷达利用同一原理：雨点移近雷达的速度越快，反射回来的微波频率即声调就越高图1 。
And structure of the wind field which we obtained with doppler radar is not the real wind field ; it should be converted into two or three - dimension wind field through some methods 多普勒雷达探测到的径向风场资料必须通过一定的数学方法手段才能得到可用的二维、三维风场。
For the case of a doppler radar , the faster the raindrops move towards the radar , the higher will be the frequency ( i . e . pitch ) of the microwave reflected from raindrops ( fig 多普勒雷达利用同一原理：雨点移近雷达的速度越快，反射回来的微波频率(即声调)就越高(图1 ) 。
Based on the definition of the average ambiguity function , the numerical expression of the average ambiguity function for the rppm pulse doppler radar signal is derived in this dissertation 本文从平均模糊函数的定义出发，推导了随机脉位调制脉冲多普勒雷达信号的平均模糊函数解析表达式。
It provides an active field for development of radar techniques . this dissertation is based on the project " cfar ( constant false alarm rate ) detection for airborne pd radar " 本文是结合课题“机载脉冲多普勒雷达恒虚警检测性能研究”进行的，主要考虑如何克服地杂波影响，提高系统的检测性能。
From the point of view of the modulation of rppm , chaotic signal with stochastic characteristics is introduced as its modulation , which has the good performance just like the random signal 从随机脉位调制脉冲多普勒雷达信号调制角度出发，又引入了具有类随机性的混沌信号作为其基本调制信号，性能与采用随机信号相接近。
This paper presents an integrated comparison of object - detecting techniques , the techniques that base on millimetre wave frequency modulated pulse - doppler radar is chosen on the basis of the idiographic demand of the recws 通过对车载目标探测技术的综合比较，结合本报警系统的具体要求，选用了车载毫米波调频多普勒雷达目标探测技术。
The tests with different kinds of methods showed that the wind field retrieved by vap algorithm could get the structure of meso - scale wind field correctly , and could be used to analyze the meso - scale wind field 多种方式检验表明，单多普勒雷达vap方法反演出的水平风场可以正确地反映风场中的中-尺度结构，作为分析中尺度风场信息的依据。
Tests were presented for detecting the reliability of meso - scale 20200km wind field retrieved from single doppler radar by vap velocity azimuth process algorithm using the data observed by dual doppler radar 利用长江中下游外场实验的多普勒雷达联合观测资料，检验使用vap velocity - azimuth process方法反演中-尺度20200km水平风场的可靠性。
