基于X射线的深空无线通信基础理论与关键技术

In the field of space wireless communication, laser and microwave technology have become mature, but bottlenecks such as the limited transmission distance, the limited communication rate and so on still exist, which strongly restrict the future applications in deep space. As a result of its short wavelength and great penetrability, X-ray has no attenuation for transmission in space when its photon energy is more than 10keV (λ<0.1nm). Thus a communication technology based on X-ray for long distance signal transmission in deep space can be achieved with smaller size, lower weight and lower power. However, studies on X-ray communication and its applications still remain blank in China. X-ray communication technology will not only be a good complement to laser and microwave communications, but will also have a unique performance on those occasions where laser and microwave could have been shielded. Study on this novel space communication method with a new conception by using X-ray as information carrier will have a great scientific significance and applicable prospect. The theoretical research on X-ray space communication will be started firstly; X-ray communication channel models and coding theory will be established. Key technical problems of a wide bandwidth modulated emission source of X-ray pulse signal, detection and demodulation based on single photon of X-ray will be focused and solved. The first domestic X-ray communication laboratory will be constructed; Real-time communications of audio, photo and video with high transmission rate will be achieved. A batch of professionals will be cultivated, which will lay a firm technology foundation for the future of deep space technologies and applications.

在空间无线通信研究方面，微波和激光通信技术已比较成熟，但是面临着传输距离、通信速率有限等瓶颈问题，严重制约未来的深空应用。X射线由于波长短、穿透能力强，当光子能量大于10keV（λ<0.1nm）时，在太空中几乎是无衰减传输。因此可望在较小的体积、重量、功耗下实现远距离太空传输。 然而，在我国对于X射线通信的研究尚属空白。开展此项研究，不仅将对现有的无线通信技术起到很好的补充，而且还能在微波和激光受到屏蔽的通信场合发挥独特作用。因此，研究利用X射线作为信息载体的新概念空间通信方法具有重要的科学意义及应用前景。 首先开展X射线空间通信的理论研究，建立信道模型和编码理论；重点解决宽带宽X射线脉冲信号源的调制发射，基于X射线单光子的探测、解调等关键理论技术问题，建设我国首个X射线通信实验室，实现高速率语音、图像和视频的实验室实时数字通信；培养一批专业人才，为未来空间应用奠定扎实的技术基础。

空间X射线通信是一种在空间环境中，以X射线光子作为载波传递信息的新型通信方式。相比微波、激光等传统载波，X射线具有频率高、单光子能量大、穿透力强等特点。有望在空间环境中实现高速率、长距离的信息传输并实现特殊电磁环境下的通信保障。. 本项目围绕空间X射线通信中的传输理论构建、发射源优化设计与研制、收发天线研制及其应用探索，进行了相关理论与实验研究，取得了以下主要成果：. （1）建立了空间X射线通信的传输模型与误码率模型，得到了了X射线通信系统核心参数：传输距离、传输速率、误码率与X射线出射功率间的理论表达及制约关系。. （2）研制了用于空间X射线通信的收发天线--X射线聚焦光学，发散角可达1.5mrad，聚焦效率 36.7%@1.49keV，接近国际领先水平。此外，优化了栅控X射线源的结构参数，相同电功率下，电子打靶产生X射线的量子效率提升10%以上。. （3）设计并搭建了X射线通信演示验证系统，实现了5Mbps的数字信号传输验证。. （4）设计并搭建了一套电磁屏蔽通信验证系统，利用高能（60keV）X射线调制源与“闪烁体+光电倍增管”探测器，实现了3mm钢板屏蔽环境下的语音通信传输。. （5）设计并搭建了电子枪与X射线通信系统相互作用的实验平台，研究了空间带电粒子对X射线通信的作用，其中，背景电子产生荧光X射线的量子效率在10-5~10-6量级，对误码率的影响小于一个量级。. （6）论证了X射线用于黑障区信息传输的可行性，搭建了基于荧光灯放电的等离子体发生器，构建了X射线穿透等离子体的实验装置。结果证实X射线可以优于96%的透过率穿透厚度5cm，电子密度1016/m3量级的等离子体区域，为X射线通信在黑障区的信息传输提供了一定的理论与实验依据。