我国空间VLBI背景型号关键技术研究

Key technology of Chinese space VLBI

空间VLBI阵即发射两个射电望远镜至空间,以形成较完备的UV覆盖和良好的成图能力.我国空间VLBI于2012年入选中国科学院背景型号研究项目,以进一步凝练科学目标和攻克关键技术.经过三年的研究,凝练出的我国空间VLBI的主要科学目标为:超大质量黑洞的直接成像,精确测量中央超大黑洞的质量,研究活动星系核巨大能源之谜,研究喷流的形成、加速和准直机制等.在关键技术研究方面也取得了重要进展.设计了实现?45?(3σ)的高精度高稳定度姿态控制方案.设计并研发了满足Q波段观测的10 m口径高精度星载可展开天线.研发了噪声温度K波段约30 K、Q波段约60 K的星载致冷接收机样机和最大带宽512 MHz的星载天文数据处理器样机.明确了星上高稳定频率基准的两种实现方案,确定了能够满足Q波段观测干涉损失小于0.01的主动型星载氢钟、研发了地面氢钟信号上传的基准信号闭环传输实验系统.科学目标的凝练和关键技术研究的进展为空间VLBI的立项打下了良好基础.

Chinese Space VLBI was selected as a background research project to further refine scientific objectives and overcome key technologies in 2012. After three years of research, we condensed out the main scientific objectives of Chinese space VLBI, i.e., directly imaging of the super massive black hole, accurate measurement of the mass of the central black hole, research on the mystery of the great energy of active galactic nuclei, the formation of the jet, the acceleration and collimation mechanism, etc. Important progress has been made in the research of key technologies. The attitude control method with high precision of 45 （3 sigma） is proposed. A high precision onboard deployable antenna with 10 m diameter for Q-band VLBI observation is developed. An onboard cryogenic receiver prototype with K-band noise temperature of 30 K and Q-band of 60 K, and an onboard astronomical data processor prototype with the maximum bandwidth of 512 MHz are developed. Two methods of high accuracy frequency reference are confirmed. The active type of onboard H-Maser which can satisfy the Q-band observation with the interference loss less than 0.01 is determined. A close-loop reference signal transmission experiment system based on the ground H-Maser signal is developed. Research progress and key technologies of concise scientific objectives has laid a good foundation for the space VLBI Project.