在探测目标尺寸小且距离远时，由于光电系统的视场角很小，有效的目标前级引导是光电系统跟瞄目标的前提。目标引导的本质是将大地坐标系下的目标点转换至光电系统局部坐标系下，转换过程中引入一系列旋转和平移参数，其准确程度决定了最终的目标引导精度。提出基于无人机航迹的光电系统引导误差校正方法，通过围绕光电系统周围无人机航迹数据，求解引导数据计算过程中坐标变换的最优参数，进而提高目标引导精度。在本项目搭建的实验装置上实现了方位引导标准方差小于0.052°，俯仰引导标准方差小于0.04°，最大误差不超过0.7°。目标前级引导的引导精度越高，光电系统捕获目标速度越快，对于提高目标处置相应速度具有重要意义。

Integrated photonics provides a route to both miniaturization of quantum key distribution (QKD) devices and enhancing their performance. A key element for achieving discrete-variable QKD is a single-photon detector. It is highly desirable to integrate detectors onto a photonic chip to enable the realization of practical and scalable quantum networks. We realize a heterogeneously integrated, superconducting silicon-photonic chip. Harnessing the unique high-speed feature of our optical waveguide-integrated superconducting detector, we perform the first optimal Bell-state measurement (BSM) of time-bin encoded qubits generated from two independent lasers. The optimal BSM enables an increased key rate of measurement-device-independent QKD (MDI-QKD), which is immune to all attacks against the detection system and hence provides the basis for a QKD network with untrusted relays. Together with the time-multiplexed technique, we have enhanced the sifted key rate by almost one order of magnitude. With a 125-MHz clock rate, we obtain a secure key rate of 6.166 kbps over 24.0 dB loss, which is comparable to the state-of-the-art MDI-QKD experimental results with a GHz clock rate. Combined with integrated QKD transmitters, a scalable, chip-based, and cost-effective QKD network should become realizable in the near future.

We employ quantum state and process tomography with time-bin qubits to benchmark a city-wide metropolitan quantum communication system. Over this network, we implement real-time feedback control systems for stabilizing the phase of the time-bin qubits and obtain a 99.3% quantum process fidelity to the ideal channel, indicating the high quality of the whole quantum communication system. This allows us to implement a field trial of high-performance quantum key distribution using coherent one way protocol with an average quantum bit error rate and visibility of 0.25% and 99.2% during 12 h over 61 km. Our results pave the way for the high-performance quantum network with metropolitan fibers.