Time filter

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Wang J.,State Key Laboratory of Astronautics Dynamics | He Z.,National University of Defense Technology | Pan X.,Beijing Institute of Control Engineering | Zhou H.,National University of Defense Technology
Proceedings of the American Control Conference

As one of the main parts for a satellite's attitude measure and control system, star trackers and gyros tend to be damaged in the actual on-orbit operation. That often makes the satellite fail to finish the given task. In this paper, an approach is proposed to detect, identify and diagnose the fault for gyro and star tracker in a satellite's attitude determination system. The model errors, including the model uncertainty and the fault factors, are estimated by predictive filter based on a satellite's attitude kinematics equation firstly. And then the estimated model error is decomposed into some intrinsic mode functions (IMF) and one trend component by the empirical mode decomposition (EMD). Furthermore, the fault model for the trend component is established by the time series analysis. And the time series model's parameters and residual variance are extracted as the feature vector, which is used to construct the discriminant function for the fault diagnosis of gyro and star tracker. Finally, promising simulated experimental results demonstrate the validity and effectiveness of the proposed method. Compared with the traditional fault diagnosis method, the detection and identification precision of the approach are improved significantly. © 2013 AACC American Automatic Control Council. Source

Ma P.-B.,Tsinghua University | Ma P.-B.,State Key Laboratory of Astronautics Dynamics | Baoyin H.-X.,Tsinghua University
Guangxue Jingmi Gongcheng/Optics and Precision Engineering

By taking Mars probing for an example, an autonomous navigation method for a Mars probe based on the optical observation of Martian moon is proposed. By carrying the Mars probe on an optical camera, the method uses the camera to take the images for natural satellites of the Mars (Phobos, Deimos)and their backgrounds in the process of flying to Mars. The star position is used to determine precisely inertial pointing, then, the autonomous navigation of Mars is completed by obtained right ascension and declination data from optical observation. The sequential estimation algorithms based on Extended Kalman Filter(EKF) and Unscented Kalman Filter(UKF) are given. The results show that the precision of EKF is similar to that of the UKF, which means that the precision loss of the EKF is not much in the linearization process. At cruising in the second half, the closer is the camera to Mars, the higher the navigation precision is. When the distance is (1-5)×107 km from Mars and the data interval is set to be 1 min, the navigation accuracy can reach 10-100 km magnitude, and the speed accuracy is 0.01 m/s. When the measurement precision is 0.1″, the navigation precision is lowered an order of magnitude. In addition, the navigation precision of Deimos alone is higher than that of the Phobos, and both of them to be used will get the highest accuracy. Simulation computation results show that the autonomous navigation for Mars detectors by the Martian moon optical measurement can satisfy the requirement of high precision navigation. Source

Yi H.,State Key Laboratory of Astronautics Dynamics | Yi H.,Nanjing University of Aeronautics and Astronautics | Xu B.,Nanjing University of Aeronautics and Astronautics | Xu B.,Nanjing University | And 2 more authors.
Science China: Physics, Mechanics and Astronomy

In view of the present technology of autonomous orbit determination for navigation satellite constellation (NSC) and the geographical conditions of China, we propose a long-term semi-autonomous orbit determination scheme supported by a few ground stations for NSC in this paper. Since the effect of rotation and translation of the entire constellation relative to the inertial reference frame can bring large errors to the autonomous orbit determination using only cross-link range measurement, a few ground stations (such as 1-3) are supposed to construct the connection between the NSC and the ground. Supported by such a few ground stations, the NSC can realize long-term orbit determination called semi-autonomous orbit determination. The simulation results based on the IGS ephemeris indicate that, for a certain degree of measurement errors, the NSC can maintain its semi-autonomous orbit determination in a period of 240 days within 5 meters of URE. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg. Source

Zhang S.,PLA Air Force Aviation University | Ma L.,PLA Air Force Aviation University | Ru L.,PLA Air Force Aviation University | Zhang H.,State Key Laboratory of Astronautics Dynamics | And 2 more authors.
Dianzi Yu Xinxi Xuebao/Journal of Electronics and Information Technology

A Multi-hop Hybrid Cooperative Geographic Routing (MHCGR) algorithm with outage-probability-constrained is proposed to reduce the path length for routing in wireless sensor networks. The cooperative links using different cooperative strategies are analyzed. With theoretical analysis, the decode-amplify-and-forward hybrid cooperative strategy can further expand the transmission distance. The ideal maximum cooperative transmission distance and the location of ideal relay node are proved for per-hop cooperative transmission link. Based on the BeaconLess Geographic Routing (BLGR) algorithm, the MHCGR algorithm uses the location information of nodes to select the optimum relay node and optimum forward node for each hop. Then MHCGR algorithm forms the cooperative route from the source node to destination node by mentioned cooperative strategy. Simulation results show that, compared with the ENBGCR algorithm and the MPCR algorithm using DF strategy, the MHCGR algorithm can reduce the number of routing hop, and reduce the overall transmission power routing. © 2016, Science Press. All right reserved. Source

Cui W.,Tsinghua University | Cui W.,State Key Laboratory of Astronautics Dynamics | BaoYin H.,Tsinghua University | Li J.,Tsinghua University
Lixue Xuebao/Chinese Journal of Theoretical and Applied Mechanics

Based on the upcoming self-Mars Exploration Program of China, the whole process of the optical auto-navi during the Mars exploration cruise segment is studied in this paper. Using the design orbit of the cruise section, the selection criteria and the asteroids sequence for optical navigation are given. The length of observation data arc is set to 30 days, and the period of the observation data is 5 days. Using the weighted least squares algorithm, the position error is from 100km to 400km and the velocity error is less than 0.25 m/s when the length of observation data arc is 30 days. Source

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