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相控阵馈源(Phased array feeds, PAFs)接收机作为下一代微波接收机, 为大口径射电天文望远镜的射电干扰(Radio Frequency Interference, RFI)缓解工作带来了新的解决方法. PAFs接收机对射电望远镜焦平面的电磁波进行空域采样, 返回时域阵列信号, 使用最小方差无失真响应(Minimum Variance Distortionless Response, MVDR)波束合成器可以自适应地识别RFI的方向, 同时抑制RFI在输出信号中的功率, 从而达到提升射电望远镜灵敏度的效果. 仿真结果表明MVDR波束合成器对有源高能量的射电干扰有很强的识别能力和一定程度的缓解能力, 同时, 该波束合成器对各阵元信道中加性噪声累积引起的无源干扰有很强的抑制能力, 因此, PAFs接收机的MVDR波束合成器可以增强日益复杂电磁波环境下射电望远镜的抗干扰能力. 相似文献
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传统上都是使用基于常规波束形成(CBF)输出功率的不同进行声源的被动检测和定位。广义相关波束形成,是一种旨在将平均Toep litz相关函数用于估计波束形成的输出功率。从线性矢量水听器阵出发,分析了常规波束形成,对广义相关波束形成(GCBF)进行了深入研究,通过对广义相关波束形成器进行“W ilson”和“Bartlett”加权,可以分别得到FIM(WFIM)和CBF,对这三种波束形成器进行了理论分析和计算机仿真,结果表明三个波束形成器的分辨能力从高到低依次是:FIM、WFIM、CBF。 相似文献
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NASA is proposing a new receiving facility that needs to beamform broadband signals from hundreds of antennas. This is a similar problem to SKA beamforming with the added requirement that the processing should not add significant noise or distortion that would interfere with processing spacecraft telemetry data. The proposed solution is based on an FX correlator architecture and uses oversampling polyphase filterbanks to avoid aliasing. Each beamformer/correlator module processes a small part of the total bandwidth for all antennas, eliminating interconnection problems. Processing the summed frequency data with a synthesis polyphase filterbank reconstructs the time series. Choice of suitable oversampling ratio, and analysis and synthesis filters can keep aliasing below −39 dB while keeping the passband ripple low. This approach is readily integrated into the currently proposed SKA correlator architecture. 相似文献
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