Development of a random modulation bistatic meteor radar system for mesospheric wind measurement

本研究的目的是利用连续波伪随机调制技术研制双基地流星雷达，用于中震区(约80-100公里)的测风。本文研究的双基地流星雷达测风的技术开发要素是测量无线电波的传播时间、多普勒频移和反射点的方向向量。研究结果如下：1.研究结果如下。从与接收信号和发送码的相关函数变得最大时的延迟时间开始测量传播时间。对这些原理和信噪比进行了计算机仿真，并进行了流星实时检测的高速相关实验。为了准确测量多普勒频移和延迟时间，研制了GPS接收机和PLL频标装置。此外，为了实现精确的时间同步，利用全球定位系统卫星进行了时间同步精度的测量实验，获得了令人满意的小于1μ的同步精度。在接收端组成干涉仪，通过天线之间的相位差测量流星回波的到达方向。通过计算机仿真发现，考虑天线之间的互阻抗，优化后的天线组合可以安装在比以前更小的位置。进行了干涉仪的测量实验，获得了令人满意的方向精度小于5度。

This research aimed at developing meteor radar of bistatic arrangement using the CW pseudo random modulation technique for the wind measurement of the mesospause region (about 80-100km). The technological development elements of this research to measure wind with bistatic meteor radar are measuring propagation time of the radio wave, Doppler shift, and the direction vector of the reflection point. The results are as the following.1. Propagation time is measured from the delay time when a correlation function becomes the biggest with the receiving signal and the transmittion code. Computer simulation about these principles and the SN-ratio, and the experiment of high-speed correlation for the meteor detection in real time were done.2. For the accurate measurement of Doppler shift and the delay time, GPS receivers and PLL frequency standard devices were developed. Furthermore, the measurement experiment of the time synchronous accuracy by the GPS satellite was done for the accurate time synchronism, and it got satisfactory synchronous accuracy less than 1 μ.s.3. An interferometer is composed on the receiving side, and the arrival direction of the meteor echo was measured from a phase differences between the antennas. The optimun antennas composition was found that it could be installed in the smaller site than before considering mutual inpedance between the antenna by the computer simulation. The measurement experiment of the interferometer was done and we got satisfactory direction accuracy less than 5 degrees.