基于FPGA终端的射频干扰平台化测试及台址防护技术

A study for RFI (radio frequency interference) measurement and protection technology can give strong supports to electromagnetic compatibility designing of telescope system, spectrum management , shielding requirments , receivers designing and interference mitigation metheods, which has an important engineering significance. Based on the 110m radio telescope station of Xin Jiang, Firstly, Roach II platform is developed , and then the compatibility of the platform is tested . Based SKA RFI measurement for candidate sites and data processing methods, on which the FPGA backend is developed including the quickly testing mode, high sensitive testing mode and pulsar signal testing mode. Secondly , RFI signal identification Algorithm , statistics and analysis methods of the pulse signal is studied, then the huge testding data will be processed, statistical analyzed and classified, and the software of testing and analyzing platform is developed based on RFI tested automatic, data processing and analyzing and data management. Finally, based the topographical features of radio astronomy observory , on which the propagation model of signal is build, then the effects to the telesope of the outside interference are caculated and analyzed, and the threshold values of interference level of telesope are ensuerd. Based on the threshold values, the evaluation system of radiation properties of equipment is developed, which can do a quick and effective envalution for radiation properties of electronic devices.

射电天文台址射频干扰（RFI）测试及防护技术的研究对射电望远镜系统电磁兼容性设计、频谱管理、屏蔽需求、接收机设计及消干扰策略等提供重要依据,具有重要的工程应用价值。 本项目针对新疆110米射电望远镜台址进行RFI测试及防护技术研究。首先，搭建基于FPGA技术的Roach II 开发平台，对开发平台兼容性进行测试；基于SKA选址RFI测试系统要求及数据处理方法，开发FPGA数据处理终端，实现台址RFI快速测试、高灵敏度测试、脉冲信号测试模式。其次，研究RFI信号的鉴别方法、脉冲信号的统计与分析方法，对大量的测试数据进行数据处理、统计和分析和归类；开发基于测试、数据处理与分析、数据管理的平台化测试与分析软件。最后，建立结合地形特征的台址电波模型，预测台址外干扰到达射电望远镜的干扰效应，确定台址的环境电平敏感阈值；基于环境电平敏感阀值，开发设备辐射特性评估系统，实现电子设备辐射发射速测试与评估。

本项目针对大口径射电望远镜台址，研究射频干扰测试及防护技术，为射电望远镜系统电磁兼容性设计、频谱管理、屏蔽需求、接收机设计及消干扰策略等提供重要依据。基于Roach II 开发平台，完成实时数字频谱分析仪的开发，实时带宽2 GHz，动态范围达到50 dB，实现了高灵敏度测量模式、快速侧模式、脉冲信号监测模式测量功能。开发了自动化、高可靠性电波环境监测系统，该系统6 GHz以下频段，系统增益大于40 dB，系统噪声系数小于2 dB；7 GHz以下频段测量不确定度小于1.49 dB，具备微弱信号接收能力。基于SKA选址RFI测试系统要求及数据处理方法，提出一种准实时电波环境测量方法；研究了宽带频谱信噪分离方法及信号识别方法。.提出大口径射电望远镜馈源口面干扰电平限值量化方法，依据QTT科学需求及技术指标，针对QTT馈源干扰电平限值进行量化；建立了基于台址地形的电波传播模型，分析了现有电波传播模型的优缺点及适应性，结 QTT台址实际地形及地质特征，采用LongleyRice和双线模型，预测分析了QTT台址潜在干扰区域电磁干扰达到射电望远镜的电波路径衰减；结合大口径射电望远镜天线增益量化模型，给出了QTT台址潜在干扰区域的干扰电平限值。为QTT电磁兼容设计、台址设备电磁防护、无线电管理提供依据。依据量化的设备所在位置干扰电平限值，开发了电子设备电磁辐射特性评估系统，该系统由测试系统、电磁辐射评估软件组成。实现系统校准、电子设备的电磁辐射测量、馈源口面干扰电平限值计算、屏蔽效能评估等功能。