Spacecraft orbit evasion is an effective method to ensure space safety. In the spacecraft’s orbital plane, the space non-cooperate target with autonomous approaching to the spacecraft may have a dangerous rendezvous....Spacecraft orbit evasion is an effective method to ensure space safety. In the spacecraft’s orbital plane, the space non-cooperate target with autonomous approaching to the spacecraft may have a dangerous rendezvous. To deal with this problem, an optimal maneuvering strategy based on the relative navigation observability degree is proposed with angles-only measurements. A maneuver evasion relative navigation model in the spacecraft’s orbital plane is constructed and the observability measurement criteria with process noise and measurement noise are defined based on the posterior Cramer-Rao lower bound. Further, the optimal maneuver evasion strategy in spacecraft’s orbital plane based on the observability is proposed. The strategy provides a new idea for spacecraft to evade safety threats autonomously. Compared with the spacecraft evasion problem based on the absolute navigation, more accurate evasion results can be obtained. The simulation indicates that this optimal strategy can weaken the system’s observability and reduce the state estimation accuracy of the non-cooperative target, making it impossible for the non-cooperative target to accurately approach the spacecraft.展开更多
The controllability and observability analysis of thin plate system with parameter uncertainty is presented using the degree of controllability/observability and the robustness index. It provides a guidance to the des...The controllability and observability analysis of thin plate system with parameter uncertainty is presented using the degree of controllability/observability and the robustness index. It provides a guidance to the design of robust active vibration control for thin plate system.展开更多
This paper considers the problem of angles-only relative navigation for autonomous rendezvous. Methods for determining degree of observability （DO0） and latent range information of orbital maneuver are proposed for ...This paper considers the problem of angles-only relative navigation for autonomous rendezvous. Methods for determining degree of observability （DO0） and latent range information of orbital maneuver are proposed for analyzing and enhancing the precision of relative position and velocity estimation. The equations of angles-only relative navigation are set forth on the con- dition that optical camera is the only viable sensor for relative measurement, and expressions for the DO0 of relative navigation are obtained by using the Newton iterative method. The latent range information of orbital maneuver is analyzed, which is employed to enhance the DOO of angles-only relative navigation. Simulation result shows that DOO is effective to describe the observability level of relative position and velocity, and the latent range information is useful in enhancing the DOO of the angles-only relative navigation.展开更多
Sequential images provided by optical cameras are ideal for realizing high-precision autonomous navigation for planetary landings, but due to limited computational resources, a large amount of image information cannot...Sequential images provided by optical cameras are ideal for realizing high-precision autonomous navigation for planetary landings, but due to limited computational resources, a large amount of image information cannot be processed on deep space probes, thus the rich landmark features in the sequential images must be selected. The contribution of landmark features to navigation accuracy is usually measured in terms of observability degrees, but the traditional method only observes the locally optimal landmarks at a single moment, and the navigation accuracy will be affected by the gradual decrease of observability degrees when observing the same landmark several times in a row before landmarks are reoptimized. In this paper, we first establish of autonomous navigation model of planetary landing segment based on sequential images. Then we construct a sequential image observability degree for multiple observations, proving that it is a convex function, and giving the interval of the minimum value point, which guides the selection of landmarks with the highest observability for multiple moments. Finally, numerical simulations were conducted and verified that using sequential image observability degree to optimize landmarks for navigation can achieve higher navigation accuracy than traditional single moment selection methods, and it can provide theoretical support for the sequential image autonomous navigation in the landing segment of deep space exploration.展开更多
基金supported by the National Key R&D Program of China (2020YFA0713502)the Special Fund Project for Guiding Local Scientific and Technological Development (2020ZYT003)+1 种基金the National Natural Science Foundation of China (U20B2055,61773021,61903086)the Natural Science Foundation of Hunan Province (2019JJ20018,2020JJ4280)。
文摘Spacecraft orbit evasion is an effective method to ensure space safety. In the spacecraft’s orbital plane, the space non-cooperate target with autonomous approaching to the spacecraft may have a dangerous rendezvous. To deal with this problem, an optimal maneuvering strategy based on the relative navigation observability degree is proposed with angles-only measurements. A maneuver evasion relative navigation model in the spacecraft’s orbital plane is constructed and the observability measurement criteria with process noise and measurement noise are defined based on the posterior Cramer-Rao lower bound. Further, the optimal maneuver evasion strategy in spacecraft’s orbital plane based on the observability is proposed. The strategy provides a new idea for spacecraft to evade safety threats autonomously. Compared with the spacecraft evasion problem based on the absolute navigation, more accurate evasion results can be obtained. The simulation indicates that this optimal strategy can weaken the system’s observability and reduce the state estimation accuracy of the non-cooperative target, making it impossible for the non-cooperative target to accurately approach the spacecraft.
文摘The controllability and observability analysis of thin plate system with parameter uncertainty is presented using the degree of controllability/observability and the robustness index. It provides a guidance to the design of robust active vibration control for thin plate system.
基金supported by the National Natural Science Foundation of China (Grant No. 10902101)
文摘This paper considers the problem of angles-only relative navigation for autonomous rendezvous. Methods for determining degree of observability （DO0） and latent range information of orbital maneuver are proposed for analyzing and enhancing the precision of relative position and velocity estimation. The equations of angles-only relative navigation are set forth on the con- dition that optical camera is the only viable sensor for relative measurement, and expressions for the DO0 of relative navigation are obtained by using the Newton iterative method. The latent range information of orbital maneuver is analyzed, which is employed to enhance the DOO of angles-only relative navigation. Simulation result shows that DOO is effective to describe the observability level of relative position and velocity, and the latent range information is useful in enhancing the DOO of the angles-only relative navigation.
基金supported by the National Natural Science Foundation of China(Grant Number U20B2055)the National Natural Science Fund for Distinguished Young Scholars of China(Grant Number 61525301)
文摘Sequential images provided by optical cameras are ideal for realizing high-precision autonomous navigation for planetary landings, but due to limited computational resources, a large amount of image information cannot be processed on deep space probes, thus the rich landmark features in the sequential images must be selected. The contribution of landmark features to navigation accuracy is usually measured in terms of observability degrees, but the traditional method only observes the locally optimal landmarks at a single moment, and the navigation accuracy will be affected by the gradual decrease of observability degrees when observing the same landmark several times in a row before landmarks are reoptimized. In this paper, we first establish of autonomous navigation model of planetary landing segment based on sequential images. Then we construct a sequential image observability degree for multiple observations, proving that it is a convex function, and giving the interval of the minimum value point, which guides the selection of landmarks with the highest observability for multiple moments. Finally, numerical simulations were conducted and verified that using sequential image observability degree to optimize landmarks for navigation can achieve higher navigation accuracy than traditional single moment selection methods, and it can provide theoretical support for the sequential image autonomous navigation in the landing segment of deep space exploration.
