To diagnose the fault of attitude sensors in satellites, this paper proposes a novel approach based on the Kalman filter of the discrete-time descriptor system. By regarding the sensor fault term as the auxiliary stat...To diagnose the fault of attitude sensors in satellites, this paper proposes a novel approach based on the Kalman filter of the discrete-time descriptor system. By regarding the sensor fault term as the auxiliary state vector, the attitude measurement system subjected to the attitude sensor fault is modeled by the discrete-time descriptor system. The condition of estimability of such systems is given. And then a Kalman filter of the discrete-time descriptor system is established based on the methodology of the maximum likelihood estimation. With the descriptor Kalman filter, the state vector of the original system and sensor fault can be estimated simultaneously. The proposed method is able to esti-mate an abrupt sensor fault as well as the incipient one. Moreover, it is also effective in the multiple faults scenario. Simulations are conducted to confirm the effectiveness of the proposed method.展开更多
Target motion modes have a close relationship with the relative orientation of missile-totarget in three-dimensional highly maneuvering target interception. From the perspective of relationship between the sensor coor...Target motion modes have a close relationship with the relative orientation of missile-totarget in three-dimensional highly maneuvering target interception. From the perspective of relationship between the sensor coordinate system and the target body coordinate system, a basic model of sensor is stated and the definition of relative angular velocity between the two coordinate systems is introduced firstly. Then, the three-dimensional analytic expressions of relative angular velocity for different motion modes are derived and simplified by analyzing the influences of target centroid motion, rotation around centroid and relative motion. Finally, the relationships of the relative angular velocity directions and values with motion modes are discussed. Simulation results validate the rationality of the theoretical analysis. It is demonstrated that there are significant differences of the relative orientation in different motion modes which include luxuriant information about motion modes. The conclusions are significant for the research of motion mode identification,maneuver detection, maneuvering target tracking and interception using target signatures.展开更多
Star sensor is one of the most accurate sensors for attitude determination,out of the atmosphere.This sensor uses stars as means to determine the attitude.Attitude determination using a star sensor involves identifyin...Star sensor is one of the most accurate sensors for attitude determination,out of the atmosphere.This sensor uses stars as means to determine the attitude.Attitude determination using a star sensor involves identifying the stars in the field of view,image processing,and finally determining the attitude matrix.This paper deals with the identification of existing stars in the field of view of the star sensor.This step is known as star identification.This paper proposes three star-identification algorithms.In these algorithms existence of at least six stars in the sensor field of view is needed.These three algorithms are investigated,using simulations performed with MATLAB software;in terms of efficiency,identification time,robustness against false stars,and required memory for the database storage.The simulated star sensor is a sensor with a square-shaped field of view of dimensions of 13.8°.13.8°same as dimensions of the ASTRO-15 star-sensor.All the presented algorithms depict high efficiency and robustness against false stars.Due to the number of required stars,proposed algorithms are appropriate for the next generation of star sensors with large fields of view.展开更多
基金supported by the National Natural Science Foundation of China (60874054)
文摘To diagnose the fault of attitude sensors in satellites, this paper proposes a novel approach based on the Kalman filter of the discrete-time descriptor system. By regarding the sensor fault term as the auxiliary state vector, the attitude measurement system subjected to the attitude sensor fault is modeled by the discrete-time descriptor system. The condition of estimability of such systems is given. And then a Kalman filter of the discrete-time descriptor system is established based on the methodology of the maximum likelihood estimation. With the descriptor Kalman filter, the state vector of the original system and sensor fault can be estimated simultaneously. The proposed method is able to esti-mate an abrupt sensor fault as well as the incipient one. Moreover, it is also effective in the multiple faults scenario. Simulations are conducted to confirm the effectiveness of the proposed method.
基金supported by the Specialized Research Fund for the Doctoral Program of China Higher Education (No. 20134307110012)the National Natural Science Foundation of China (No. 61101186)
文摘Target motion modes have a close relationship with the relative orientation of missile-totarget in three-dimensional highly maneuvering target interception. From the perspective of relationship between the sensor coordinate system and the target body coordinate system, a basic model of sensor is stated and the definition of relative angular velocity between the two coordinate systems is introduced firstly. Then, the three-dimensional analytic expressions of relative angular velocity for different motion modes are derived and simplified by analyzing the influences of target centroid motion, rotation around centroid and relative motion. Finally, the relationships of the relative angular velocity directions and values with motion modes are discussed. Simulation results validate the rationality of the theoretical analysis. It is demonstrated that there are significant differences of the relative orientation in different motion modes which include luxuriant information about motion modes. The conclusions are significant for the research of motion mode identification,maneuver detection, maneuvering target tracking and interception using target signatures.
文摘Star sensor is one of the most accurate sensors for attitude determination,out of the atmosphere.This sensor uses stars as means to determine the attitude.Attitude determination using a star sensor involves identifying the stars in the field of view,image processing,and finally determining the attitude matrix.This paper deals with the identification of existing stars in the field of view of the star sensor.This step is known as star identification.This paper proposes three star-identification algorithms.In these algorithms existence of at least six stars in the sensor field of view is needed.These three algorithms are investigated,using simulations performed with MATLAB software;in terms of efficiency,identification time,robustness against false stars,and required memory for the database storage.The simulated star sensor is a sensor with a square-shaped field of view of dimensions of 13.8°.13.8°same as dimensions of the ASTRO-15 star-sensor.All the presented algorithms depict high efficiency and robustness against false stars.Due to the number of required stars,proposed algorithms are appropriate for the next generation of star sensors with large fields of view.
