微变形监测雷达技术研究

Large scale structures such as electricity transmission tower, dam, long span bridge across river, skyscrapers, railway and highway slope, and tailings dam may occur deformation while being used, especially under disastrous weather. It is necessary to monitor the deformations of them real time in order to diagnose the engineering quality, and predict potential hazard in advance. This project studies a novel deformation monitoring method and system with the advantages of long measurement distance, high temporal and spatial sampling rate, high precision etc. This system consists of two parts: high-density distributed microwave scatters installed on the measured object and ground based interferometric radar sensor. The deformation monitoring technology is converted into two basic issues: carrier phase interferometric measurement and separation of multiple scatters. This project introduces the advanced signal processing technologies in the fields of radar and ECM to solve the problem of multi-scatter separation. The digital beam forming technology is used to form a plurality of parallel narrow beams to separate the scatters from different incident directions; The synthetic bandwidth technology is used to combine multi-channel narrow band signals to an ultra-wideband radar signal to improve the range resolution; The range deception technology is used to move scatters to new virtual positions out of the same rang cell so as to separate them. Then the carrier-phase interferometric measurement method is utilized to get the displacement of each scatter. Lastly, the multi-static radar technology is used to implement three dimensional deformation measurements. The research achievements of this project can provide powerful technical support for China's disaster prevention and reduction.

大型工程如输变电塔，水库大坝，垮江大桥，摩天大楼，公路铁路边坡，尾矿坝等，在使用中均需要对其实施变形位移监测，特别是灾害环境下，以便对工程质量进行诊断，对可能发生的工程灾害进行预测预报。本项目研究一种远距离、高时空采样率、高精度的新型微变形监测方法与系统，该系统由安装在被测物体上的密集多微波散射点和地基干涉雷达组成，将微变形测量分解为多散射点分辨分离与载波相位干涉测量两个基本问题。本项目引入雷达与电子对抗领域中的先进信号处理技术来解决多散射点分辨分离。利用数字波束形成思想形成并行窄波束实现不同方向散射点的分辨分离，利用合成宽带思想将多通道窄带信号合成为超宽带雷达信号提高距离向分辨率，利用距离欺骗思想改变散射点到虚拟位置实现位于距离分辨单元内的散射点分辨分离；使用载波相位干涉测量方法计算每个散射点的位移；使用多基地雷达实现3维变形监测。本项目的研究成果可为我国减灾防灾提供强有力的技术支撑。

大型工程如输变电塔，水库大坝，跨江大桥，摩天大楼，公路铁路边坡，尾矿坝等，在使用中均需要对其实施变形位移监测，特别是灾害环境下，以便对工程质量进行诊断，对可能发生的工程灾害进行预测预报。本项目研究了一种远距离、高时空采样率、高精度的新型微变形监测方法与系统，该系统由安装在被测对象上的微波散射点和位于稳定位置的地基干涉雷达组成，在实现微波散射点分辨分离的基础上，使用相位干涉测量技术测量每个散射点的位移量。本项目对地基干涉雷达进行了改进，引入了数字波束形成技术，给出了最优权系数的计算方法，以便在期望散射点回波方向上增益最大，在其它散射点回波方向上形成零陷，解决了位于不同方向的多个散射点分辨分离问题；本项目对地基干涉雷达进行了改进，引入了合成宽带处理技术，给出了将多个窄带信号合成一个宽带信号的方法，以便增加雷达带宽，提高距离向分辨率，降低实现难度，解决了位于不同距离的多个散射点分辨分离问题；本项目对微波散射点进行改进，引入了相参转发技术，对收到的信号进行延迟转发或者移频转发，并研究了转发器的泄漏抵消技术，以便减小转发信号对接收信号的影响，解决了位置接近的多个散射点分辨分离问题。本项目的研究成果为研制相应的实验仪器打下了很好的基础，可为我国减灾防灾事业提供强有力的技术支撑。