基于稀疏随机采样技术的天线近远场快速测试算法研究

Sampling is the bridge between analog source signal and digital signal. With the rapid progress of information technologies, the demands for information are increasing dramatically. The traditional sampling of signal must obey the Shannon Sampling theorem, that is, the frequency of sampling signal must be at least twice of original signal to avoid losing the information of signal. However, further improving the Nyquist frequency will increase the complexity for data capturing, and be too difficult to achieve for hardware.So the existing systems are very difficult to meet the challenges of high speed sampling, large volume data transmission and storage. How to acquire information in signal efficiently is an urgent problem in electronic information fields.Due to the constraints of physical or technical conditions and noises,the presence of image degradation to different extents is unavoidable during the process of image formation,transmission and recordation.And therefore,based on the degraded observation,image restoration is essential,and it applies a recovery process aiming for a better precision approximation and information acquisition of the original image. The results of experiments show the validity of the algorithm.In the study of CS based data acquisition methods, we introduce Analog to Information converter (AIC) into compressive sensing data processing,and proposes both digital and analog solutions of AIC in anechoic chamber antenna measurement system.

近年来稀疏随机采样理论在信号处理领域得到高度关注，其非相关测量过程突破传统的奈奎斯特采样定理，有效地降低数据的采样率。据此研发的"单相素相机"只用一个相素即可获得整个图像画面。利用该理论，拟将该理论引入到微波暗室天线近远场测试过程中，有望解决复杂电磁环境中超大数据量的采集与传输问题。在微波暗室天线测试过程中随机测试几个方位数据，即可获得整个天线全方位测试结果。前期实验证明随机测30%数据即可完全重构。本文研究的主要内容有：一、在基于稀疏随机采样的天线近远场数据获取方法研究中，通过对电磁信号的分析，建立匹配滤波体制下的回波信号稀疏表示模型；二、结合现有的稀疏信号重建算法，研究复数域中稀疏重建算法和非相关测量矩阵性能评价标准，选择适合天线近远场的重建算法与测量矩阵。三、将稀疏随机采样测试技术应用到微波暗室电磁兼容环境中，形成一种快速高效的测试实现方案。四、最终在微波暗室中验证该方案正确性。

本项目将压缩感知理论引入微波暗室天线近远场测试过程中，期望通过稀疏随机采样技术提高微波暗室天线各项数据的采集测试速度。在基金的资助下，主要完成了以下几项内容研究：（1）项目周期内，建设了一个大型微波暗室，可用于各类天线测试。依托该微波暗室的测试环境，对各项理论数据进行了验证。（2）提出了一种基于稀疏随机采样的信号测试分析方法，建立了匹配滤波体制下的暗室内电磁信号稀疏表示模型。引入稀疏随机采样理论：稀疏表示，非线性观测，信号重构；选择适合天线近远场测试的重建算法与测量矩阵；将稀疏随机采样测量技术与微波暗室测量技术结合。（3）将基于压缩感知的模拟/信息转换器AIC引入微波暗室测量测试，提出了一种基于压缩感知的微波暗室数据快速获取方法。（4）编写了基于压缩感知的暗室测量软件平台，在远场测试中直接加入AIC系统模型，实现天线远场快速测试。（5）引入系统性能指标体系和评估分析方法等关键技术，有效实现了对各类电大尺寸目标雷达散射截面问题的压缩感知加速求解。