The algorithm of autonomous orbit determination for the probe around small body is studied. In the algorithm, first, the observed images of the body are compared with its pre-computed model of the body to obtain the l...The algorithm of autonomous orbit determination for the probe around small body is studied. In the algorithm, first, the observed images of the body are compared with its pre-computed model of the body to obtain the location of the limb features of the body in the inertial coordinate. Second, the information of the images and features in utilized to obtain the position of the probe using the Levenberg-Marquardt algorithm. The position is then input to an extended Kalman filter which determines the real time orbit of the probe. Finally, considering the effective of the irregular small body shape perturbation and the small body model parameter error on the orbit determination precise, the procedure of autonomous orbit determination is validated using digital simulation.展开更多
Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for ang...Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.展开更多
The purpose of initial orbit determination,especially in the case of angles-only data for observation,is to obtain an initial estimate that is close enough to the true orbit to enable subsequent precision orbit determ...The purpose of initial orbit determination,especially in the case of angles-only data for observation,is to obtain an initial estimate that is close enough to the true orbit to enable subsequent precision orbit determination processing to be successful.However,the classical angles-only initial orbit determination methods cannot deal with the observation data whose Earth-central angle is larger than 360°.In this paper,an improved double r-iteration initial orbit determination method to deal with the above case is presented to monitor geosynchronous Earth orbit objects for a spacebased surveillance system.Simulation results indicate that the improved double r-iteration method is feasible,and the accuracy of the obtained initial orbit meets the requirements of re-acquiring the object.展开更多
Navigation via signals of opportunity(NAVSOP)is able to realize positioning by making use of hundreds of different signals that are all around us.A method to realize NAVSOP for low earth orbit(LEO)satellites is propos...Navigation via signals of opportunity(NAVSOP)is able to realize positioning by making use of hundreds of different signals that are all around us.A method to realize NAVSOP for low earth orbit(LEO)satellites is proposed in this paper,in which the global navigation satellite system(GNSS)authorized signals are utilized as the signal of opportunity(SOP).At first,the carrier recovery technique is studied under the premise that the pseudo-code is unknown.Secondly,a method based on characteristics of Doppler frequency shift is proposed to recognize the navigation satellites.Thirdly,the extended Kalman filter(EKF)is utilized to estimate the orbital parameters by using carrier phase measurements.Finally,the proposed method is evaluated by using signals generated by a satellite navigation data simulator.The simulation results show that the proposed method can successfully realize navigation via GNSS authorized signals.展开更多
以“嫦娥六号”任务搭载的巴基斯坦立方星为研究对象,系统分析了其轨道特性、力学环境及测量手段,重点探讨了影响轨道变化的主要摄动因素。在缺乏测距和甚长基线干涉测量(Very Long Baseline Interferometry,VLBI)支持的条件下,提出了...以“嫦娥六号”任务搭载的巴基斯坦立方星为研究对象,系统分析了其轨道特性、力学环境及测量手段,重点探讨了影响轨道变化的主要摄动因素。在缺乏测距和甚长基线干涉测量(Very Long Baseline Interferometry,VLBI)支持的条件下,提出了一种基于三向测速的轨道确定方法,建立了三向测速模型,并对测速误差进行分析;同时,设计了适用于稀疏观测模式的定轨策略,并完成了误差评估。此外,对立方星轨道的长期演化进行了深入分析。研究结果表明:三向多普勒测速残差的均方根误差为2 mm/s,轨道确定的位置精度优于1 km;立方星轨道主要受月球非球形引力摄动和地球质点引力摄动的影响,三体引力在其轨道演化中起到了重要作用。轨道演化预测显示,立方星的近月距离预计于2025年4月缩小至小于月球半径。研究为深空探测任务中的微小卫星轨道确定与演化分析提供了参考。展开更多
空间碎片数量的显著增长导致航天器遭受碰撞的风险急剧提升,亟需发展高精度的空间碎片态势感知定位与碰撞威胁评估技术.面向空间碎片目标,提出一种融合多源异构观测数据的目标感知定位方法,并集成物理机制建模与机器学习算法,构建了一...空间碎片数量的显著增长导致航天器遭受碰撞的风险急剧提升,亟需发展高精度的空间碎片态势感知定位与碰撞威胁评估技术.面向空间碎片目标,提出一种融合多源异构观测数据的目标感知定位方法,并集成物理机制建模与机器学习算法,构建了一种碰撞威胁等级混合评估机制.在感知定位层面,建立了统一的多卫星观测数学模型,有效融合了距离、角度与速度三类异构观测数据,进而设计了一种基于Huber加权与迭代重优化的列文伯格-马夸特法(Levenberg-Marquardt,LM)算法,显著提升了定位精度及其在异常数据条件下的算法鲁棒性.在威胁评估层面,提出了一种混合决策框架,该框架融合了改进的碰撞概率物理计算模型与随机森林分类器,统筹考虑碰撞概率估计与潜在动能碰撞后果的影响,实现了对碎片威胁等级的高效精准划分.仿真实验验证结果表明,所提出的定位算法在位置估计均方根误差(root mean square error,RMSE)方面性能显著优于传统最小二乘估计及几何解析法;同时,威胁等级分类模型展现出较高的整体分类准确率,且随机森林分类器的判别性能优于逻辑回归模型.本研究为天基空间目标监视任务与航天器自主规避决策支撑提供了有效的技术解决方案.展开更多
基金This project was supported by the 15th Plan National Defence Science & Tehnology and Civil Space Previous Study Project.
文摘The algorithm of autonomous orbit determination for the probe around small body is studied. In the algorithm, first, the observed images of the body are compared with its pre-computed model of the body to obtain the location of the limb features of the body in the inertial coordinate. Second, the information of the images and features in utilized to obtain the position of the probe using the Levenberg-Marquardt algorithm. The position is then input to an extended Kalman filter which determines the real time orbit of the probe. Finally, considering the effective of the irregular small body shape perturbation and the small body model parameter error on the orbit determination precise, the procedure of autonomous orbit determination is validated using digital simulation.
基金supported by the National Natural Science Foundation of China (12272168)the Foundation of Science and Technology on Space Intelligent Control Laboratory (HTKJ2023KL502015)。
文摘Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.
文摘The purpose of initial orbit determination,especially in the case of angles-only data for observation,is to obtain an initial estimate that is close enough to the true orbit to enable subsequent precision orbit determination processing to be successful.However,the classical angles-only initial orbit determination methods cannot deal with the observation data whose Earth-central angle is larger than 360°.In this paper,an improved double r-iteration initial orbit determination method to deal with the above case is presented to monitor geosynchronous Earth orbit objects for a spacebased surveillance system.Simulation results indicate that the improved double r-iteration method is feasible,and the accuracy of the obtained initial orbit meets the requirements of re-acquiring the object.
基金This work was supported by the National Natural Science Foundation of China(61673212).
文摘Navigation via signals of opportunity(NAVSOP)is able to realize positioning by making use of hundreds of different signals that are all around us.A method to realize NAVSOP for low earth orbit(LEO)satellites is proposed in this paper,in which the global navigation satellite system(GNSS)authorized signals are utilized as the signal of opportunity(SOP).At first,the carrier recovery technique is studied under the premise that the pseudo-code is unknown.Secondly,a method based on characteristics of Doppler frequency shift is proposed to recognize the navigation satellites.Thirdly,the extended Kalman filter(EKF)is utilized to estimate the orbital parameters by using carrier phase measurements.Finally,the proposed method is evaluated by using signals generated by a satellite navigation data simulator.The simulation results show that the proposed method can successfully realize navigation via GNSS authorized signals.
文摘空间碎片数量的显著增长导致航天器遭受碰撞的风险急剧提升,亟需发展高精度的空间碎片态势感知定位与碰撞威胁评估技术.面向空间碎片目标,提出一种融合多源异构观测数据的目标感知定位方法,并集成物理机制建模与机器学习算法,构建了一种碰撞威胁等级混合评估机制.在感知定位层面,建立了统一的多卫星观测数学模型,有效融合了距离、角度与速度三类异构观测数据,进而设计了一种基于Huber加权与迭代重优化的列文伯格-马夸特法(Levenberg-Marquardt,LM)算法,显著提升了定位精度及其在异常数据条件下的算法鲁棒性.在威胁评估层面,提出了一种混合决策框架,该框架融合了改进的碰撞概率物理计算模型与随机森林分类器,统筹考虑碰撞概率估计与潜在动能碰撞后果的影响,实现了对碎片威胁等级的高效精准划分.仿真实验验证结果表明,所提出的定位算法在位置估计均方根误差(root mean square error,RMSE)方面性能显著优于传统最小二乘估计及几何解析法;同时,威胁等级分类模型展现出较高的整体分类准确率,且随机森林分类器的判别性能优于逻辑回归模型.本研究为天基空间目标监视任务与航天器自主规避决策支撑提供了有效的技术解决方案.
