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Parametric resonance orbit analysis for irregular shaped asteroids based on the perturbed particle-linkage model

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Research in Astronomy and Astrophysics 2020年第12期20卷 205-220页

作者：钱霙婧司震杨晓东张伟 Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures College of Mechanical EngineeringBeijing University of TechnologyBeijing 100124China

There are plentiful asteroids moving periodically around their central primaries, such as the Sun. Due to the perturbation of the central primary, the gravitational force of the perturbed asteroid system varies periodically. In this paper, based on the idea of integrating the solar gravitational force as a part of the system instead of treating it as perturbation, the parametric resonance response is investigated. A novel type of stable parametric resonance orbits has been detected. It is found that the steady-state motion amplitude of parametric resonance orbit is determined by the frequency-response equation. The stability of the novel orbits has also been demonstrated. The new type of orbits may contribute to possible asteroid exploration missions.

关键词： asteroids:general space vehicles celestial mechanics

A simulation experiment on the GM estimation for Comet 133P/Elst-Pizarro

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Research in Astronomy and Astrophysics 2021年第1期21卷 158-164页

作者： Wu-Tong Gao Jian-Guo Yan Wei-Tong Jin Xuan Yang Chen Yang Mao Ye Fei Li Jean-Pierre Barriot l State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China China Academy of space Technology Beijing 100094China Geodesy Observatory of Tahiti University of French PolynesiaBP 657098702 FaaaTahitiFrench Polynesia

In China’s asteroid mission to be launched around 2025,(7968)133 P/Elst-Pizarro(hereafter 133 P)will be the second target,after a visit to asteroid(469219)Kamo’*** paper describes a simulation of precise orbit determination for the spacecraft around comet 133 P,as well as estimation of its gravitational parameter(GM)value and the solar radiation pressure coefficient Cr for the *** cometocentric distances of 200,150 and 100 km orbits are considered,as well as two tracking modes:exclusive two-way range-rate mode(Earth station to spacecraft)and combinations of two-way range-rate and local spacecraft onboard ranging to the *** to exclusive two-way range-rate,the introduction of local ranging observables improves the final GM uncertainties by up to one order of *** ephemeris error in the orbit of 133 P is also considered,and we show that,to obtain a reliable estimate of the GM for 133 P,this error cannot exceed a one km range.

关键词： celestial mechanics space vehicles comets:individual(133P/Elst-Pizarro) methods:statistical

Reducing loss of significance in the computation of Earth-based two-way Doppler observables for small body missions

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Research in Astronomy and Astrophysics 2021年第8期21卷 75-90页

作者：金炜桐李斐鄢建国杨轩叶茂郝卫峰 Thomas Paul Andert Jean-Pierre Barriot State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang 050200China Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China Universitat der Bundeswehr München NeubibergBayern85579Germany University of French Polynesia BP 6570F-98702 Faa'aTahitiFrench Polynesia

Two-way Doppler measurement is a typical Earth-based radiometric technique for interplanetary spacecraft navigation and gravity science *** most widely used model for the computation of two-way Doppler observables is Moyer’s differenced-range Doppler(DRD) formula,which is based on a Schwarzschild approximation of the Solar-System ***,the computation of range difference in DRD formula is sensitive to round-off errors due to approximate numbers defined by the norm IEEE754 in all *** paper presented two updated models and their corresponding detailed instructions for the computation of the two-way Doppler observables so as to impair the effects of this type of numerical *** two models were validated by two case studies related to the Rosetta mission—asteroid Lutetia flyby and comet 67 P/Churyumov-Gerasimenko orbiting *** these two cases,the numerical noise from the updated models can be reduced by two orders-of-magnitude in the computed two-way Doppler *** results showed an accuracy from better than 6 × 10^(-3) mm s^(-1) at 1 s counting time interval to better than 3 × 10^(-5) mm s^(-1) at 60 s counting time interval.

关键词： methods:numerical space vehicles planets and satellites:general

spacecraft Doppler tracking with possible violations of LLI and LPI: a theoretical modeling

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Research in Astronomy and Astrophysics 2014年第3期14卷 319-328页

作者： Xue-Mei Deng Yi Xie Purple Mountain Observatory Chinese Academy of Sciences Key Laboratory of Modern Astronomy and Astrophysics Nanjing UniversityMinistry of Education School of Astronomy & space Science Nanjing University

Currently two-way and three-way spacecraft Doppler tracking techniquesare widely used and play important roles in control and navigation of deep space mis-sions. Starting from a one-way Doppler model, we extend the theory to two-way andthree-way Doppler models by making them include possible violations of the localLorentz invariance （LLI） and the local position invariance （LPI） in order to test theEinstein equivalence principle, which is the cornerstone of general relativity and allother metric theories of gravity. After taking the finite speed of light into account,which is the so-called light time solution （LTS）, we make these models depend on thetime of reception of the signal only for practical convenience. We find that possibleviolations of LLI and LPI cannot affect two-way Doppler tracking under a linear ap-proximation of LTS, although this approximation is sufficiently good for most cases inthe solar system. We also show that, in three-way Doppler tracking, possible violationsof LLI and LPI are only associated with two stations, which suggests that it is betterto set the stations at places with significant differences in velocities and gravitationalpotentials to obtain a high level of sensitivity for the tests.

关键词： space vehicles techniques: radial velocities gravitation

The deconvolution of lunar brightness temperature based on the maximum entropy method using Chang'e-2 microwave data

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Research in Astronomy and Astrophysics 2015年第2期15卷 293-304页

作者： Shu-Guo Xing Yan Su Jian-Qing Feng Chun-Lai Li National Astronomical Observatories Chinese Academy of Sciences

A passive and multi-channel microwave sounder onboard the Chang＇e-2 orbiter has successfully acquired microwave observations of the lunar surface and subsurface structure. Compared with the Chang＇e-1 orbiter, the Chang＇e-2 orbiter obtained more accurate and comprehensive microwave brightness temperature data, which are helpful for further research. Since there is a close relationship between mi- crowave brightness temperature data and some related properties of the lunar regolith, such as the thickness, temperature and dielectric constant, precise and high resolution brightness temperature data are necessary for such research. However, through the detection mechanism of the microwave sounder, the brightness temperature data ac- quired from the microwave sounder are weighted by the antenna radiation pattern, so the data are the convolution of the antenna radiation pattern with the lunar brightness temperature. In order to obtain the real lunar brightness temperature, a deconvolution method is needed. The aim of this paper is to solve the problem associated with per- forming deconvolution of the lunar brightness temperature. In this study, we introduce the maximum entropy method （MEM） to process the brightness temperature data and achieve excellent results. The paper mainly includes the following aspects： first, we introduce the principle of the MEM; second, through a series of simulations, the MEM has been verified as an efficient deconvolution method; and third, the MEM is used to process the Chang＇e-2 microwave data and the results are significant.

关键词： space vehicles instruments: microwave sounder Moon: brightness temperature methods: maximum entropy method

Radio frequency compatibility analysis for BDSBAS and GPS/WAAS

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Research in Astronomy and Astrophysics 2021年第8期21卷 235-244页

作者： Cheng Liu Wei-Guang Gao Jun Lu Yi Zhou Shan-Shan Chen Beijing institute of Tracking and Telecommunication Technology Beijing 100094China BeiDou Application Research Academy of Norinco Group Beijing 100089China space Star Technology Beijing 100094China

Radio frequency signal compatibility is the basis of interoperability of the Satellite eBased Augmentation System(SBAS).SBAS should abide by relative international radio regulations of International Telecommunication Union(ITU) and meet the compatibility requirements of radio frequency signal between the Global Navigation Satellite System(GNSS)/SBAS,in order to avoid negative mutual *** to ITU Proposal and related reference and assumptions,the paper made simulation of signal receiving maximum power in the Bei Dou Satellite-Based Augmentation System(BDSBAS)global signal *** then,interference of BDSBAS to Global Positioning System(GPS)/WAAS(Wide Area Augmentation System) on L1/L5 bands were calculated and analyzed,with equivalent carrierto-noise ratio as the evaluation *** result shows that the carrier-to-noise ratio decrease of GPS/WAAS caused by BDSBAS B1 C and B2 a signals are extremely lower than inter-system interference of GPS/WAAS,and thus can be ignored in practical ***,BDSBAS will not cause the service performance degradation of GPS and WAAS.

关键词： space vehicles methods:data analysis celestial mechanics

Analysis of the wide area differential correction for BeiDou global satellite navigation system

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Research in Astronomy and Astrophysics 2018年第11期18卷 17-28页

作者： Ran Li Yue-Ling Cao Xiao-Gong Hu Cheng-Pan Tang Shan-Shi Zhou Xin Meng Li Liu Ran-Ran Su Zhi-Qiao Chang Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China University of Chinese Academy of Sciences Beijing 100049China Shanghai Key Laboratory of space Navigation and Position Techniques Shanghai 200030China College of Surveying and Geo-Informatics Tongji UniversityShanghai 200092China Beijing Global Information Application and Development Center Beijing 100094China

The regional BeiDou Satellite System, or BDS2, broadcasts a differential correction as Equivalent Satellite Clock Correction to correct both orbit and satellite clock errors. For the global BDS, or BDS3, satellite orbit and clock corrections conforming with RTCA standards will be broadcast to authorized users. The hybrid constellation and regional monitoring network pose challenges for the high precision separation of orbit and satellite clock corrections. Three correction models of kinematic,dynamic and Two-way Satellite Time Frequency Transfer(TWSTFT)-based dynamic were studied to estimate the satellite orbit and clock corrections. The correction accuracy of the three models is compared and analyzed based on the BDS observation data. Results show that the accuracies(root mean square, RMS) of dual-frequency real-time positioning for the three models are about 1.76 m, 1.78 m and 2.08 m respectively, which are comparable with the performance of WAAS and EGNOS. With dynamic corrections, the precision of Precise Point Positioning(PPP) experiments may reach about 23 cm after convergence.

关键词： celestial mechanics methods: data analysis space vehicles

Attitude dynamics and control of spacecraft using geomagnetic Lorentz force

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Research in Astronomy and Astrophysics 2015年第1期15卷 127-144页

作者： Yehia A.Abdel-Aziz Muhammad Shoaib National Research Institute of Astronomy and Geophysics (NRIAG) Helwan Cairo 11721Egypt University of Hail Department of Mathematics PO BOX 2440 Kingdom of Saudi Arabia

Attitude stabilization of a charged rigid spacecraft in Low Earth Orbit using torques due to Lorentz force in pitch and roll directions is considered. A spacecraft that generates an electrostatic charge on its surface in the Earth’s magnetic field will be subject to perturbations from the Lorentz force. The Lorentz force acting on an electrostatically charged spacecraft may provide a useful thrust for controlling a spacecraft’s orientation. We assume that the spacecraft is moving in the Earth’s magnetic field in an elliptical orbit under the effects of gravitational, geomagnetic and Lorentz torques. The magnetic field of the Earth is modeled as a non-tilted dipole.A model incorporating all Lorentz torques as a function of orbital elements has been developed on the basis of electric and magnetic fields. The stability of the spacecraft orientation is investigated both analytically and numerically. The existence and stability of equilibrium positions is investigated for different values of the charge to mass ratio（α＊）. Stable orbits are identified for various values of α＊. The main parameters for stabilization of the spacecraft are α＊and the difference between the components of the moment of inertia for the spacecraft.

关键词： space vehicles atmospheric effects celestial mechanics kinematics and dynamics

Adaptive Pinpoint and Fuel Efficient Mars Landing Using Reinforcement Learning

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IEEE/CAA Journal of Automatica Sinica 2014年第4期1卷 397-411页

作者： Brian Gaudet Roberto Furfaro the Research Engineer Department of Systems and Industrial EngineeringUniversity of Arizona Department of Systems and Industrial Engineering Department of Aerospace and Mechanical EngineeringUniversity of Arizona

Future unconstrained and science-driven missions to Mars will require advanced guidance algorithms that are able to adapt to more demanding mission requirements, e.g. landing on selected locales with pinpoint accuracy while autonomously flying fuel-efficient trajectories. In this paper, a novel guidance algorithm designed by applying the principles of reinforcement learning(RL) theory is presented. The goal is to devise an adaptive guidance algorithm that enables robust, fuel efficient,and accurate landing without the need for off line trajectory generation and real-time tracking. Results from a Monte Carlo simulation campaign show that the algorithm is capable of autonomously following trajectories that are close to the optimal minimum-fuel solutions with an accuracy that surpasses that of past and future Mars missions. The proposed RL-based guidance algorithm exhibits a high degree of flexibility and can easily accommodate autonomous retargeting while maintaining accuracy and fuel efficiency. Although reinforcement learning and other similar machine learning techniques have been previously applied to aerospace guidance and control problems(e.g., autonomous helicopter control), this appears, to the best of the authors knowledge, to be the first application of reinforcement learning to the problem of autonomous planetary landing.

关键词： Trajectory Mars Mathematical model Algorithm design and analysis space missions Atmospheric modeling Learning (artificial intelligence) space vehicles