When the Cassini spacecraft finally plunged into the Saturnian atmosphere on 2017 September 15, China’s deep space telescope pointed to Saturn to observe Cassini and study the Saturnian upper neutral atmosphere. In this first Chinese Saturnian radio science experiment, X band Doppler velocity radio science data between the deep space telescope and the Cassini spacecraft were obtained. After removing Saturnian and solar gravity effects, Earth rotation effect, the remaining Saturnian atmosphere drag information was retrieved in the Cassini final plunge progress. Saturn’s upper neutral atmosphere mass density profile is approximately estimated based on atmosphere mass density derived principally by real orbit measurement data. Saturn’s upper neutral atmospheremass density from76 000 km to 1400 km is estimated fromthe orbit measurement data, the mass density results are about from 1.4 × 10−15 kg cm−3 to 2.5 × 10−14 kg cm−3.

具有斜转台的三轴天线系统在遥感卫星高速数据接收领域已得到普遍应用,而在测控数传地面综合系统中,为了兼顾数传接收与地面测量控制,考虑使用三轴天线,但需要通过外测修正算法,提高外测数据的可用性.分析了三轴天线的特性,通过分析三轴天线的结构,建立了合理的坐标系,提出了相应的数据修正的数学算法,并通过工程实践跟踪卫星验证了外测数据修正方法的可行性.

多阵面相控阵星间链路管理设备既解决了传统星间链路设备卫星与地面站间精密测量和数传、全球系统的自主导航功能的问题,又缓解了地面星间链路管理设备不能满足"北斗"全球系统部署的困难.分析了多阵面相控阵星间管理设备的特点,讨论了多相控阵同时工作下阵面保护的难题,提出了天线设计与波束管理软件控制两种方法相结合的解决方案.

The construction of China's deep space network supports China's deep space missions,such as explorations of Lunar,Mars,Small planets,Jupiter,and etc. To validate China's deep space network performance and obtain the radio measurement raw data,dozens of radio open loop measurement experiments of Juno which is one of Jupiter's probe on orbit were accomplished. These open loop measurement experiments are the first time conducted by the China's deep space stations tracking a in-orbit probe in Earth-Jupiter distance. VLBI terminate sampling and recording facilities were utilized to record Juno's raw carrier signal,which was processed to extract Doppler frequency between Juno and the deep space station. In this paper,the combining method of Fast Fourier transform,Chirp Z transform and signal local reconstruction was utilized to obtain Juno's Doppler frequency. The results show that Juno's open loop Doppler frequency is at the level of 10 μHz,which effectively validated the method of deep space open loop measurement and provide valuable reference for China's future deep space missions.

"卡西尼号"（Cassini）探测器于北京时间1997年10月15日发射升空,经过6年8个月漫长太空旅行后进入环绕土星的轨道,开展土星系统探测任务,并于2017年9月15日坠入土星大气层,完成最后科学使命。20年间,Cassini任务取得了为数众多的科学与技术成果和全新的科学发现。在2017年9月15日Cassini探测器谢幕之旅中（图1）,北京航天飞行控制中心联合西安卫星测控中心佳木斯

After nine years travel,New Horizons launched in 2006 by NASA flew by Pluto on July 14, 2015.New Horizons has therefore become the first spacecraft to ever travel to Pluto.Planetary radio research club from the Chinese Academy of Sciences took this opportunity to begin to measure signals from New Horizons with the 60-meter radio telescopes at Sheshan Shanghai Observation Station and Heilongjiang Jiamusi deep space exploration base.The reception and analysis work is done with Radio Science Receiver developed by Southeast University.Measurement results include Doppler frequency and phase information of the downlink signal.Accuracy evaluation of the measurements is also evaluated.

China deep space controlling network (CDSCN)constructed and applied in lunar missions can do range and range-rate as well as VLBI together with remote control and telemetry at radio band for deep space tracking like Mars missions and other deep space exploration missions.Remote deep space exploration missions shift the direction of up-link and down-link signals because of increasing time duration of microwave transmission between aiming planets and ground.This is a challenge for remote exploration telecommunication because it is not possible to do up-link and down-link radio communications simultaneously.For a typical Mars exploration,the disadvantages of deep-space measurements with single radio antenna controlling system are analyzed.Several suggestions for updating and upgrading controlling equipments are made which are necessary for remote communication on deep space exploration missions.The up and down-links could be time-divided on a solo antenna at a given deep space tracking station.Or the up and down-links are set up in multiple stations with solo antenna each with 3-way open loop method.The DSN/JPL/NASA method are used to set up multiple antennas at each deep space tracking station,with antennas share the same time-frequency standard,and the antennas at same station realizing close-loop up and down link real-time TT & C continuously.

Pointing accuracy is one of the most important characteristics for a large radio telescope;it is very fundamental for telescope running. To ensure good performance for measuring the flux density of a radio source, pointing accuracy must be kept within 10% of telescope beam size. In this paper we present results of large measurements of telescope points for Jiamusi 66m radio telescope, and show the basic-parameter model and the fitting residuals of pointing data. We find that even after the correction of a new best-fitting basic-parameter model, the pointing uncertainty data still have a systematic variations of concentration along with the azimuth and elevation, which we believe is caused by the high order variations of the angle between the azimuth axis and elevation axis as well as the gravity deformation. We improve the basic-parameter model for the pointing corrections, and we get much improved pointing accuracy for Jiamusi 66m radio telescope from 45″to less than 20″.