【作者】 张帆；

【导师】 谭萍；

【作者基本信息】 华中科技大学 ， 电子与通信工程， 2011， 硕士

【摘要】 采用阵列信号处理技术实现对空间信号的测向与定位一直是人们研究的热点问题,尤其是以MUSIC算法为代表基于特征分解的超分辨测向技术因其在理想阵列流型下所特有的超分辨率得到了广泛的关注与应用。然而在工程应用中,实际的阵列流型由于天线阵元的位置误差、互耦误差、方向图不一致性误差以及阵列接收通道的幅相不一致性误差等因素的影响始终与理想阵列流型存在偏差,从而导致这类算法分辨性能急剧恶化甚至失效。因此,针对实际应用系统设计有效的阵列误差校准方法成为实现超分辨测向的关键技术之一。本文主要对云闪探测子系统中阵列接收前端的通道不一致性误差进行了分析,并综合考虑了系统的软硬件资源以及均匀圆阵特有的圆对称性,设计了一种基于圆阵阵列中心发射校准信号的有源校准方案。通过对云闪阵列接收前端各通道进行增益、噪声系数以及输入端散射参量S11参数的测试,验证了各通道之间存在明显的不一致性问题,其中各通道针对同一激励源的输出功率最大差值可达4dB,并且经过实验验证该系统在无阵列校准条件下得到的DOA估计结果与理论计算值也存在较大偏差。本文中有源阵列校准方案的具体实现上主要从两项关键技术着手进行设计,一项是校准源发生单元的硬件设计,包括电路原理图设计、PCB设计以及关键输出信号频谱优化,使得该单元实现同时输出阵列校准及本振信号,并且可通过上位机控制校准信号的输出状态,以满足校准方案的实际需要。目前该硬件单元针对第一版发现的问题点成功进行了改版,经测试能够很好的达到系统的要求。另一项则是校准方案的实验验证与确定,先后验证了板间通道校准和阵列中心辐射校准源两种不同的校准源馈入方式对DOA估计结果的影响,并分析了原因,最终选定了合理有效的阵列中心辐射校准源的校准方案。该校准方案经过多台探测子系统多次多发射点的外场实验验证,能够稳定有效的对阵列误差进行校准,并配合后级超分辨算法获取准确的DOA估计结果。更多还原

【Abstract】 Using array signal processing technology to finding the direction and location of electromagnetic wave signals has been a hot topic for researchers, especially the super-resolution DOA Estimation technology using MUSIC algorithm based on eigenvalue decomposition have a lot of attention and application for its super-resolution in ideal array manifold. However, in engineering applications, deviations from the true array manifold, typically resulting from antenna position errors, mutual coupling and array channels mismatch can seriously degrade the algorithms’ performance. So, finding an effective array errors calibration method has become the key technology for the super-resolution DOA Estimation technology. This paper mainly analyse the amplitude and phase errors in the receiver of the cloud lightening detection system and design a active array calibration method based on emitting the sources in the array center on considering the system’s resources and the circular symmetry of uniform circular arrayThrough verifying the performance of the receiver including channel gain,noise figure and S-parameter, we can see the obvious channel mismatch in the receiver. When receiving the same signal, maxium difference between the channel output powers is up to 4dB. And the array errors have also caused deviation of the DOA results in outfield experiments.Realization can be divided to two parts. One is the hardware designing of the generation of calibration sources, including schematic design and PCB design. At present, the hardware unit has been revised once and can well meet the requirements of the system.The other is selecting the suitable methods of the calibration sources feeding into the system, which is feeding the calibration sources in the center of antenna array.Through verifying from outfield experiments using several detecting systems in multiple emitting points, the array calibration method in this paper can calibrate the array errors efficiently and stablely, and guarantee the DOA performance.更多还原