深空通信新型射频技术
2017-03-31胡赟鹏沈彩耀沈智翔张德伟
胡赟鹏++沈彩耀++沈智翔++张德伟++屠振
摘 要:深空通信射频技术是深空通信关键技术之一,该课题围绕我国未来深空探测任务的需求,重点突破适应深空通信需求的低噪声温度射频前端设计与多天线组阵增强系统相关关键技术,实现深空探测数据回传的高效可靠接收。课题设计完成低噪声温度射频前端,X/Ka频段等效噪声温度达到25 K/50 K以下。突破HEMT晶体管低温建模关键技术,实现低温器件参数的高精度提取。针对超导滤波器的关键工艺技术,以及超导滤波器运用软件精确设计展开研究。提出了支持现有天线以任意形态组阵的全新多天线信号增强处理结构,同时设计研制了多天线信号合成样机及试验验证系统。该结构可充分利用现有的接收天线和接收机,适用于非均匀组阵下各种调制方式、不同调制参数信号的无数据辅助合成,实现了对信号的盲处理。区别于传统的仅利用固定参考信号实现信号间的时延估计方法,提出了一种基于准合成输出信号作为参考时延对准算法,提高参考信号的信噪比,时延估计性能在低信噪比条件下其估计性能改善更为明显。提出并实现了一种不依赖于单路信号信噪比计算的多天线信号合成权值盲估计算法,该算法无需任何信号先验信息和定时同步,解决了信号最大比合并中权值估计的通用性问题。针对通信信号特点,研究了多天线信号多层次联合处理结构,同时实现了符号检测与同步的联合处理,以及各路信号间的联合同步与联合符号检测。在多路极低信噪比条件下,与传统合成结构的相比能够进一步提升处理增益。课题所取得成果对拓展更远距离的深空探测,实现极低信噪比条件下,大容量回传数据的可靠接收具有十分重要的意义。针对我国深空探测发展的需求,该课题通过关键技术突破与创新有效提升深空数据传输能力,为我国未来深空科学技术与工程实施提供有力支撑,推动我国空间科学与应用的原创性发展。
关键词:深空通信 低噪声温度射频前端 多天线信号合成
Abstract: Deep space communication radio frequency (RF) technology is one of the key technologies for deep space communication. Around the needs of the deep space exploration, this subject has made a significant breakthrough in key areas of low noise temperature RF front-end design as well as multiple antenna arraying techniques to meet the needs of high reliable and efficient data transmission in deep space communication. This project developed a low noise temperature RF front-end with X/Ka band equivalent noise temperature reached 25 K/50 K. It made breakthrough in the key technology of modeling HEMT transistor in low temperature, and also realized the high-precision extraction of low temperature parameters. Superconducting filter on the key technology and using software accurate designing are specially researched. Besides, this project proposed a new multiple-antenna signal enhancement processing structure, which supports the existing antenna array in arbitrary form, and designed multiple antennas combining prototype and test system. This structure is suitable for non-uniform group array under various signal modulation mode, different modulation parameters. This project proposed a new time delay alignment algorithm using quasi combined signal as the reference, which improve the signal-to-noise ratio(SNR) of the reference signal, thus improve the time delay estimation performance. This project proposed a new weights estimation method, which is independent on single channel signal SNR calculation and does not need any priori information and timing synchronization. For the characteristics of communication signals, this project studied multi-antenna multi-level joint processing structure, achieving joint symbol detection and synchronization, as well as multiple signals joint synchronization and symbol detection. The above cooperative processing structure can achieve parameters estimation from multiple antenna at the same time, which can further enhance the processing gain under low SNR conditions. The above achievements are significant to be expanded to greater distance deep space exploration, achieving high-capacity high reliable data reception under low SNR condition. This project can effectively improve the deep space data transmission ability, which provide strong support for future deep space science, technology and engineering implementation in China.
Key Words: Deep space communication; Low noise temperature RF front-end; Multiple-antenna signal combining
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