首页期刊导航|Advances in space research: The official journal of the Committee on Space Research
期刊信息/Journal information
Advances in space research: The official journal of the Committee on Space Research
Pergamon Press
Pergamon Press
0273-1177
Advances in space research: The official journal of the Committee on Space Research/Journal Advances in space research: The official journal of the Committee on Space ResearchSCIEIISTP
Pablo MirallesKathiravan ThangavelAntonio Fulvio ScannapiecoNitya Jagadam...
4959-4986页
查看更多>>摘要：The continuing Machine Learning (ML) revolution indubitably has had a significant positive impact on the analysis of downlinked satellite data. Other aspects of the Earth Observation industry, despite being less susceptible to widespread application of Machine Learning, are also following this trend. These applications, actual use cases, possible prospects and difficulties, as well as anticipated research gaps, are the focus of this review of Machine Learning applied to Earth Observation Operations. A wide range of topics are covered, including mission planning, fault diagnosis, fault prognosis and fault repair, optimization of telecommunications, enhanced GNC, on-board image processing, and the use of Machine Learning models on platforms with constrained compute and power capabilities, as well as recommendations in the respective areas of research. The review tackles all on-board and off-board applications of machine learning to Earth Observation with one notable exception: it omits all post-processing of payload data on the ground, a topic that has been studied extensively by past authors. In addition, this review article discusses the standardization of Machine Learning (i.e., Guidelines and Roadmaps), as well as the challenges and recommendations in Earth Observation operations for the purpose of building better space missions.
查看更多>>摘要：This work proposed a novel adaptive neural dynamics (AND)-based speed control strategy for the stable sub satellite's retrieval of the tethered satellite system (TSS). The new control scheme is implemented by adjusting the retrieval speed only. An analytical speed function is used to ensure stable retrieval without libration motion overall. A high-efficiency adaptive neural dynamic control law with the retrieval speed as control input is used to eliminate the libration motion. In the control loop, the tension in the tether is monitored and restrained directly. The Lyapunov stability of the control law is proved analytically. The simulation results show the proposed adaptive neural dynamics-based speed control strategy is very effective in keeping a stable retrieval by adjusting the retrieval speed only. The libration motions can be eliminated promptly in a fast manner with limited control input and tension constrain.
查看更多>>摘要：Approach and docking with space tether system has the advantages of less system complexity and lower cost compared with conventional rendezvous and docking which are usually essential operations in on-orbit service of spacecraft. This paper deals with the relative dynamics and control of the tethered on-orbit service satellite for the process of approach and docking by retrieving tether. Considering the system safety, it is necessary to keep the pitch angle constant or it varying in a small range during the approach. Therefore, we propose a control law for tether retrieval. Specifically, the relative dynamics equations are established to analyze the effects of orbit eccentricity, orbit altitude, and tether length rate on the system dynamics as well as investigate the property of pitch motion. Then the retrieval control law with constant pitch angle constraint is proposed using the dynamic inverse method based on the dynamics analyses. We further discuss the feasible region of orbit eccentricity and constant pitch angle for the control law to retrieve the tether. The numerical simulation experiments show that the proposed law can realize stable retrieval while maintaining a constant pitch angle.
查看更多>>摘要：The increasing number of Resident Space Objects poses a serious threat to the safe operation of satellites. Alongside with mitigation policies, it is fundamental to predict the trajectories of such objects which requires the accurate estimation of the physical characteristics that influence their orbits. An important role is played by the area-to-mass ratio, i.e., the ratio between the area exposed to the atmosphere/the Sun and the mass of the space object for the LEO/MEO and GEO region. Current literature proposes several approaches for the estimation of the area-to-mass ratio, ranging from semi-analytical to numerical methods. As regards the latter category, recent studies have focused on classification or regression algorithms for specific types of orbits (e.g., sun-synchronous, geostationary). In this context, this paper proposes a machine learning-based regression approach for the estimation of the ballistic coefficient (i.e., the product between the drag coefficient and the area-to-mass ratio) in Low Earth Orbit, covering a wide set of orbital parameters. Using a synthetic space catalogue, the performance of different types of machine learning techniques is evaluated and compared. A sensitivity analysis is carried out to analyse the effect on performance of the number of trainings, the propagation time, the number of objects of the training data set, and the frequency of the measurements. The applicability of the presented approach is tested and discussed using both real (i.e., based on publicly available catalogues of Two-Line Elements) and synthetic datasets.
查看更多>>摘要：Based on plant root adaptive growth theory of monocotyledons, a stiffness optimization method of locking unit for multi-rigid body space manipulator is proposed. The optimization process of locking unit stiffness is transformed into the increase and elimination of spring constraints. The kinematic model of the locking unit is established, and the equivalent method of the locking stiffness of the locking unit is proposed to make the three-dimensional support model of the locking unit correspond to the three-dimensional stiffness of the locking space. According to the proposed optimization method of locking unit and equivalent method of locking stiffness, a parallel optimization method is used to optimize the stiffness of space manipulator locking unit. The stiffness optimized locking system is compared with the conventional locking system, and the higher fundamental frequency of the system is verified by simulation analysis, which proves the effectiveness of the stiffness optimization method of the locking unit.
查看更多>>摘要：This paper proposes a numerical searching and ergodic mappings method to seek the naturally bounded relative orbits near the triangular libration points in the Earth-Moon system. An orbital energy saved numerical continuation method along one axis is proposed and the Poincare map near the triangular libration points is obtained, based on which two characteristic parameters are defined to generate the naturally bounded relative motions, i.e., the crossing interval period and the reference angle. Then, a numerical searching method is employed to generate an ergodic mapping and a neural network is utilized to realize the transformation from the ergodic mappings to orbital states. By pairing the ergodic mappings of different initial orbital states, the naturally bounded relative motion realized can remain for a long time and does not diverge.
查看更多>>摘要：By developing an analytical model considering the J_2 perturbation and small eccentricity, the effects of an in-track maneuver on the umbra and penumbra arcs of near-circular orbits are analyzed. The effectiveness of the analytical model is validated by comparing it with the numerical difference and a published model for the cylindrical eclipse. Three major conclusions are draw. First, the proposed analytical model agrees well with the numerical difference method in common situations, and the effect of an in-track maneuver on the eclipse arc center is much smaller than that on the eclipse arc length. Second, although the precision of the proposed analytical model decreases as the eccentricity increases, the effects of a small in-track maneuver on the orbital eclipse could be considered as small values in common situations. Those effects could be notable as the maneuver magnitude increases. Third, when the orbital sun angle approaches the critical angle defined by the ratio of the Earth radius to the satellite's semimajor axis, the effects of an in-track maneuver on the penumbra arc length could not be a small value any more, the precision of the analytical model would be considerably degraded. In the neighborhood of the critical angle, the differences between the effects of an in-track maneuver on the umbra, penumbra and cylindrical eclipse reach the maximum. Moreover, the reasons for the properties presented above are successfully explained by the analytical partial derivatives in the developed model.
Lorenzo Pasqualetto CassinisTae Ha ParkNathan StaceySimone D'Amico...
5061-5082页
查看更多>>摘要：This paper introduces an adaptive Convolutional Neural Network (CNN)-based Unscented Kalman Filter for the pose estimation of uncooperative spacecraft. The validation is carried out at Stanford's robotic Testbed for Rendezvous and Optical Navigation on the Satellite Hardware-In-the-loop Rendezvous Trajectories (SHIRT) dataset, which simulates vision-based rendezvous trajectories of a ser-vicer spacecraft to PRISMA's Tango spacecraft. The proposed navigation system is stress-tested on synthetic as well as realistic lab imagery by simulating space-like illumination conditions on-ground. The validation is performed at different levels of the navigation system by first training and testing the adopted CNN on SPEED+, Stanford's spacecraft pose estimation dataset with specific emphasis on domain shift between a synthetic domain and an Hardware-In-the-Loop domain. A novel data augmentation scheme based on light randomization is proposed to improve the CNN robustness under adverse viewing conditions, reaching centimeter-level and 10 degree-level pose errors in 80% of the SPEED+ lab images. Next, the entire navigation system is tested on the SHIRT dataset. Results indicate that the inclusion of a new scheme to adaptively scale the heatmaps-based measurement error covariance based on filter innovations improves filter robustness by returning centimeter-level position errors and moderate attitude accuracies, suggesting that a proper representation of the measurements uncertainty combined with an adaptive measurement error covariance is key in improving the navigation robustness.
查看更多>>摘要：Bayesian filtering is a popular class of estimation algorithms for addressing the space object tracking problem. Bayesian filters assume a random physical system with known statistics of various uncertainty sources. The major challenge is that the exact knowledge of some random process may not be available for analysis, preventing us from performing a probabilistic characterization of the epistemic uncertainty components. In this paper, we explore the use of the Outer Probability Measures (OPMs) to achieve a faithful uncertainty representation derived from all available yet imperfect information in the process of space object tracking. Leveraging the concepts of OPMs, a refined Possibilistic Admissible Region approach is proposed, in which the initial orbital state is modeled using a novel parameter estimation method. The OPM filter is employed to integrate different types of data sources in the presence of assumed ignorance. The efficacy of the developed method is validated by several space object tracking scenarios using real radar measurements and two-line elements data.
查看更多>>摘要：Stabilizing a malfunctioning satellite to a low rotating speed is required to ensure safe capture. The detumbling method based on a flexible contactor is efficient and safe due to its relatively large operating force and soft contact. However, flexible components of the target such as the long solar panel will deform large under this intense external force, which makes accurate modeling and analysis of the detumbling process particularly challenging. In this paper, the dynamic problem of detumbling a rotating satellite with large-deformation solar panels is first studied. The target satellite is accurately modeled via global frame approaches, where the new visco-elastic thin plate element of the absolute nodal coordinate formulation is proposed to describe the solar panels. Then the contact model is built based on the geometric relation between the flexible contactor and the solar panel. Finally, dynamic performances during detumbling are compared between flexible and rigid targets, and the detumbling process of the highly flexible satellite is analyzed. All simulation results show that the flexibility of the target should be considered carefully in contact detumbling tasks.
NETL
NSTL
Elsevier