Fundamental investigations concerning the analysis, detection, and compensation of calibration errors in MIMO radar and MIMO SAR imaging systems

有关 MIMO 雷达和 MIMO SAR 成像系统中校准误差的分析、检测和补偿的基础研究

• 批准号: 506408783
• 负责人: Professor Dr.-Ing. Martin Vossiek
• 金额: --
• 依托单位: Lehrstuhl für Hochfrequenztechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/506408783?language=en
• 关键词: Fundamental; investigations; concerning; analysis; detection

In the field of radar systems, MIMO-SAR concepts (MIMO = multiple-input multiple-output; SAR = Synthetic Aperture Radar) become more and more important. In this concept, radar sensors with multiple transmit and receive antennas or the target move along a trajectory. In the following, the sets of measurement signals from all transmit and receive combinations, recorded at multiple points along the trajectory, are reconstructed to an image. Applications of MIMO-SAR can be found in remote sensing, in the imaging of the surroundings of ground and air vehicles, or in security and medical technology. MIMO radar measurements are always impaired by imperfections in the MIMO array, for example because of mutual coupling between the antenna elements or incorrectly assumed antenna positions and phase centers. To minimize these impairments, the arrays are calibrated prior to commissioning. Apart from the fact that high-quality calibration is costly and not always possible, parameters change depending on temperature, environment and aging. As a result, MIMO radar systems always process error-prone measurements. In a typical MIMO SAR measurement, the MIMO array is moved to different positions with approximately constant spacing. When considering the resulting overall measurement data set, it is now affected by periodic measurement errors caused by the imperfectly calibrated MIMO array. As a consequence, the signals from each target are modulated, yielding deterministic errors that result in the appearance of ghost targets in the radar images. Similar errors also occur in large scale MIMO arrays, that are intended for future imaging radar systems. Although the degradation of image quality and target detection probability can be significant, this effect has so far hardly been documented and theoretically analyzed. Therefore, the aim of this project is to systematically investigate the fundamental effects of calibration errors on MIMO SAR systems. This will be done analytically, in simulations, as well as by measurement. Models and calculation methods will be derived that allow an exact characterization of the ghost targets induced by calibration errors. The targeted results thus provide a fundamental basis to enable the better assessment of measurement results of imaging MIMO SAR systems under realistic conditions. In addition, research will be conducted on how MIMO SAR apertures and measurement procedures should be designed so that the occurrence of ghost targets is minimized even if calibration errors are present. Another aspect is to investigate how the deterministic structure of calibration errors can be used as a novel metric to assess the quality of the calibration of an antenna array in situ during the ongoing radar operation on the one hand, and to improve or evaluate calibration procedures on the other hand.

在雷达系统领域，MIMO-SAR概念（MIMO=多输入多输出；SAR=合成孔径雷达）变得越来越重要。在这个概念中，具有多个发射和接收天线的雷达传感器或目标沿着轨迹移动。接下来，沿轨迹的多个点记录的来自所有发射和接收组合的测量信号组被重建为图像。 MIMO-SAR 的应用可以在遥感、地面和空中车辆周围环境成像、或者安全和医疗技术中找到。 MIMO 雷达测量总是会受到 MIMO 阵列缺陷的影响，例如由于天线元件之间的相互耦合或错误假设的天线位置和相位中心。为了最大限度地减少这些损害，阵列在调试之前进行了校准。除了高质量校准成本高昂且并不总是可行之外，参数还会根据温度、环境和老化而变化。因此，MIMO 雷达系统总是处理容易出错的测量结果。在典型的 MIMO SAR 测量中，MIMO 阵列以近似恒定的间距移动到不同的位置。当考虑最终的整体测量数据集时，它现在受到由不完美校准的 MIMO 阵列引起的周期性测量误差的影响。结果，来自每个目标的信号被调制，产生确定性误差，导致雷达图像中出现幽灵目标。类似的错误也发生在用于未来成像雷达系统的大规模 MIMO 阵列中。尽管图像质量和目标检测概率的下降可能很严重，但迄今为止这种影响几乎没有被记录和理论上分析。因此，本项目的目的是系统地研究校准误差对MIMO SAR系统的基本影响。这将通过分析、模拟以及测量来完成。将导出模型和计算方法，以准确表征由校准误差引起的鬼目标。因此，目标结果为更好地评估现实条件下成像 MIMO SAR 系统的测量结果提供了基础基础。此外，还将研究如何设计MIMO SAR孔径和测量程序，以便即使存在校准误差也能最大限度地减少鬼目标的出现。另一方面是研究如何将校准误差的确定性结构用作一种新的度量标准，一方面在正在进行的雷达操作期间评估天线阵列现场校准的质量，另一方面改进或评估校准程序另一方面。