The Chang'E5 (CE-5)missionhas excellenttelemetry, tracking,and controlresources,providingconvenientconditionsfor verifyingnew ground-basedradiomeasurementmethods,engineeringapplications,and scientificresearch.This paperfocuseson the open-loopvelocitymeasurementand applicationof the CE-5probe.First,an open-loopDopplerfrequencyextractionalgorithmbasedon signalreconstructioncross-correlationwas proposed,and the completeimplementationstepsfrom signalinputand signalprocessingto observationoutputwere established.Second,the CE-5open-loopvelocitymeasurementexperimentwas performedbasedon the Chinadeepspacestation,and the CE-5downlinksignalswereprocessedand analyzed.The resultsshowthat the open-loopDopplermeasurementaccuracyofthe CE-5orbiterreachesthe levelof 2-3 MHz,whichis 3-4 timesbetterthan the basebandDopplermeasurementaccuracyof the deep spacestation.Third,the high-accuracyorbit determinationeffectivelyverifiesthe applicabilityofopen-loopvelocitymeasurement.The resultsshowthat the orbitdeterminationresidualof open-loopvelocitymeasurementis 0.12 mm/s,and the orbit determinationresidualof basebandvelocitymeasurementis 0.46 mm/s.Finally,the gravitationalredshiftverificationmethodfor the multibodyproblemwas proposed,and the potentialapplicationfeasibilityof gravitationalredshiftverificationbasedon open-loopvelocitymeasurementwas theoreticallyanalyzed.Theverificationexperimentschemewas preliminarilydesigned.Basedon the open-loopvelocitymeasurementresultsof theexistingCE-5orbiter, a specialexperimentfor gravitationalredshiftverificationcan be designed,and the gravitationalredshiftdetectionaccuracyis expected to achieve the level of 10-4to 10-5

As a radiant light source within the dynamic range of most spacecraft payloads, the Moon provides an excellent reference for on-orbit radiometric calibration. This research hinges on the precise simulation of lunar spectral irradiances and Earth-based Moon observation geometry. The paper leverages the Hapke model to simulate the temporal changes in lunar spectral irradiances, utilizing datasets obtained from the Lunar Reconnaissance Orbiter Camera (LROC). The research also details the transformation process from the lunar geographic coordinate system to the instantaneous projection coordinate system, thereby delineating the necessary observational geometry. The insights offered by this study have the potential to enhance future in-orbit spacecraft calibration procedures, thereby boosting the fidelity of data gathered from satellite observations.

嫦娥五号（CE-5）任务具有天地联合的优势测控资源，为地基无线电测量新方法验证、工程应用与科学研究提供了优越条件。本文重点开展CE-5探测器开环测速精细提取及应用。首先，提出了基于信号重构互相关的开环测速多普勒频率提取算法，建立了从信号输入、信号处理到观测量输出的完整实现步骤；然后，基于中国深空网开展了CE-5轨道器开环测速试验，经信号处理分析结果表明：CE-5轨道器开环测速精度达到2~3mHz水平，优于深空站基带测速精度3~4倍；其次，通过CE-5轨道器精密定轨，有效验证开环测速观测量应用效果，结果表明：开环测速的定轨残差为0.12mm/s，基带测速的定轨残差为0.46mm/s；最后，提出了基于深空探测器的多体问题引力红移验证方法，从理论上分析了高精度开环测速在引力红移验证方面潜在应用可行性，初步设计了引力红移验证设想方案，评估了以现有CE-5轨道器开环测速结果为依据，建议可考虑开展引力红移验证专项试验，有望实现10-4~10-5水平的引力红移验证精度。

美国DE系列、法国INPOP系列和俄罗斯EPM系列数值星历表是目前公认处于世界领先的3种行星数值历表.计算100 a(1960-2060年)间,3种数值历表中大行星(包含月球)相对地球和相对太阳系质心的位置坐标差分最大值及均方根.结果表明,3种历表对太阳系质心的测量存在百米到公里量级的偏差,EPM2017与其他两个相差较大.考虑相对地心的位置,水星和金星的历表精度在百米量级;火星的历表精度在百米到公里量级;木星和土星的历表精度在几公里到几十公里量级;天王星和海王星的历表精度在几百公里到几千公里量级;月球历表的精度在分米到米量级,其径向距离精度在分米量级.此结果为地月空间科学实验及深空探测应用提供了支持和依据.

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.

China Chang’E-3 performed soft landing at the plains of Sinus Iridum on lunar surface on December 14th 2013 successfully; it opened a new window for observing lunar surface with radiometric tracking which many lunar scientific researchers always pursue for. Since July 2014, OCEL (Observing Chang’E-3 Lander with VLBI) project has been conducted jointly by IVS (International VLBI Service of Geodesy and Astrometry) and BACC (Beijing Aerospace Control Center), a global IVS R&D network augmented with two China Deep Space Stations configured for OCEL. This paper presents the current status and preliminary result of the OCEL and mainly focuses on determination of the lander position, which is about 7 meter in height and 14 meter in plane of lunar surface with respect to LRO (Lunar Reconnaissance Orbiter). Based on accuracy analysis, further optimized OCEL sessions will make use of this target-of-opportunity, the Chang’E-3 lunar lander, as long as it is working. With higher accurate radiometric observables, more prospective contribution to earth and lunar science is expected by combining with LLR.

Real-time, high-accuracy frequency-phase estimation is the critical mission of Doppler tracking, which is a primary technique for deep space spacecraft navigation and planetary radio science experiments. Usually, the analog intermediate frequency signal is digitalized and converted to baseband by signal processing hardware platforms called digital back-ends (DBEs) and parameter estimation is performed by extra high performance computers. In this paper, a novel real-time, high-accuracy parameter estimator called a hardware-based integrated parameter estimator (HIPE) is proposed and implemented inside DBEs. An adaptive frequency tracker is proposed to make the initial signal detection, frequency tracking, and data reduction. Then a parameter estimation is sequentially obtained by a modified dechirp technique and a high-resolution spectral analysis technique called spec-zooming. Further, a folding architecture is designed to save hardware resources when realizing spec-zooming in a field programmable gate array (FPGA). An example design is deployed on a DBE with Xilinx Virtex-6 FPGA and an ARM processor. The performance is verified by X-band observations of Mars Express (MEX) and New Horizons (NH). Under an integration time of 1s, HIPE only takes 2.2ms to process single-channel baseband data and provides frequency accuracies of 7 mHz and 30 mHz for the tested MEX and NH data. HIPE is implemented inside DBE, so the extra computer is no longer required and the pressure of data transmission or storage is greatly relieved. It could easily be extended to parallel multi-channel, real-time processing and would be a powerful method for Doppler measurement in deep space exploration missions, such as the Chinese mission to Mars to be undertaken by 2020.

利用最新的GRAIL月球重力数据和LRO地形数据,计算重力/地形导纳及其相关性.结果表明,最新的测月数据能够在球谐系数达到500阶的时候依然保持比较高的相关性,精度得到很大的提高.全月重力/地形导纳在50阶以下(波长大于～ 220 km),之后迅速增加,维持在110 mgal/km附近.利用Gauss-Newton迭代法计算得到全月弹性平均厚度Te =11.7 km,表明很有可能月球地形在月球早期就已经形成.

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.

目前,月面太阳能依然是人类进行月面探测的最主要能量来源之一.因此,对月面光照情况的研究不仅为月球的形成演化研究提供重要科学信息,同时也对月球探测有着重要的工程和国防意义.本文利用LRO(Lunar Reconnaissance Orbiter)获得最新的高精度((1/1 024)°)的月面地形数据,创新性地提出了一个基于多线程编程技术的计算算法,实现了并行计算.分辨率和计算效率都较之前的结果有了很大提高,在较短的时间内生成了月球两极地区最低太阳高度角数据库,为今后的月球两极区域高精度和时间长跨度的光照条件分析提供了数据支持.

The illumination analysis algorithm at mid-low latitudes is improved. Taking Aristarchus plateau （AP） as an example，the high resolution and high accuracy LOLA data from the LRO satellite and DE/LE430 lunar planetary ephemeris are used to quantitatively calculate and analyze the illumination characteristics of AP based on the Moon’s libration model. The results show that the illumination rates of AP area are all over 0.35，and the illumination condition of flat area is good. The illumination rates vary greatly in different regions because of the influence of terrain. The maximum illumination rate is higher than the minimum above 30%. Considering the typical long term libration effects，the results of 18.6 years show that the change of illumination rate is small and stable，which is an important reference for the research on the evolution of the lunar surface.

"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

The Doppler tracking data of the Chang'e 3 lunar mission is used to constrain the stochastic background of gravitational wave in cosmology within the 1 mHz to 0.05 Hz frequency band. Our result improves on the upper bound on the energy density of the stochastic background of gravitational wave in the 0.02 Hz to 0.05 Hz band obtained by the Apollo missions, with the improvement reaching almost one order of magnitude at around 0.05 Hz. Detailed noise analysis of the Doppler tracking data is also presented, with the prospect that these noise sources will be mitigated in future Chinese deep space missions. A feasibility study is also undertaken to understand the scientific capability of the Chang'e 4 mission, due to be launched in 2018, in relation to the stochastic gravitational wave background around 0.01 Hz. The study indicates that the upper bound on the energy density may be further improved by another order of magnitude from the Chang'e 3 mission, which will fill the gap in the frequency band from 0.02 Hz to 0.1 Hz in the foreseeable future.

Focusing on China’s lunar，Venus，Mars and Jupiter missions，we take DE405，DE421 and DE430 as samples to analyze their dynamical models and observation data. By evaluating the accuracies and performances，we investigate the effects on an orbiter around the Moon，Venus and Mars，and also the visible of the Jupiter from earth，and recommend that it is better to use the most new ephemeris for exploration missions. We also briefly introduced the Lunar Radio Ranging experiments in NAOC and its application to lunar ephemeris.

In the field of space low-frequency gravitational-wave detection, the high-precision microwave Doppler measurement based on the ground tracking station has been performed for more than 40 years. During the extension phase of Chang'E-3 lander, lunar microwave ranging technology of sub-millicycle accuracy was realized based on the independent development planetary radio receiver. Then use the raw data of lunar-earth ranging measurement in X-band, after the deduction of the earth atmospheric aberration, ionospheric disturbance, ground equipment thermal noise and the interplanetary plasma influence, the microwave differential ranging and velocity measurement of higher accuracy was verified. Using this technology, a scheme which is using differential ranging and velocity measurement in Chang'E-4 2-way and 4-way measurement is proposed as a precursor technology. On these bases, using the microwave link of Chang'E-3 lander and the communication navigation satellite in L4 / L5 libration point, a new method of low-frequency gravitational-wave detection, which has the sensitivity of 10(-17)-10(-19), is suggested.

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.

An Extreme ultraviolet (EUV) Camera was installed onboard the Chinese lunar surface landing mission, the Chang’E-3 lander, as a useful method to observe the Earth plasmasphere. This EUV optical payload obtained more than 600 moon-based Earth plasmasphere images since December 14, 2013. However, due to errors of unknown size and origin in the platform attitude control of the lander and in the EUV telescope pointing control during the mission operating periods, the geocentric coordinates in these EUV images are not fixed in the same position of CCD pixel. Before adequately calibrating, these positioning offsets will introduce extra errors into the analysis of the plasmaspheric structure. With only a little insufficient telemetry information, an effective calibrating method of circle-based differential algorithm is suggested and demonstrated, for automatically and precisely detecting the geocentric position in each EUV image of Chang’E-3 mission. In each EUV image, the tested method uses the outline of a circle as the basic unit to capture the contour for the bright region based on the spectral characteristic. Then, the center of the extracted circle is adopted as the geocentric position for the image. The preliminary analysis shows that this method can effectively detect the geocentric position being always consistent with the recognition result by the basic hand labor method. It is found that the radius of the circles varies from month to month from December, 2013 to May, 2014. The monthly averages of radius show relative notable positive correlation and negative correlation with the changes of both Zenith angle of the Earth at the landing area of Chang’E-3 lander, and the Earth-moon distance, respectively. This method and results here will benefit the Chang’E-3 EUV study.

Planetary radio science experiments have been carried out in Chinese lunar exploration missions of Chang’e-1/2/3. The astronomical VLBI technique was adopted for tracking and orbiting of the Chinese Chang’e 1 & 2 missions, and played an important role in positioning the orbit injection and hard landing. Besides the orbiters’ POD work and lander positioning work using open loop and close loop R&RR and VLBI tracking data, many other experiments have also been done. In orbiter missions, the lunar gravity field model was improved by using Chang’e-1 R&RR data, and new topographical features were discovered based on the new model. Also, the micro-wave passive method was used to study the lunar surface and sub-surface features. In extended mission of Chang’e-2, POD by R&RR and VLBI played the key role in L2 Lissajous orbit mission,and in Toutatis asteroid fly-by mission. In Chang’e-3 landing mission, a 3-way open loop lunar radio phase ranging and Doppler technique was suggested and tested. This method, called Lunar Radio Phase Ranging (LRPR) can be a new space geodetic technique to measure the station position, earth tide and rotation, lunar orbit, tide and liberation, by means of independent observation, or to work together with Lunar Laser Ranging. Also, it can be used in future Mars mission.