Application of the discrete Kalman filter for radar pointing error reduction

Author(s):  
J. Walls ◽  
M. Greene ◽  
J. Stensby
2019 ◽  
Vol 41 (14) ◽  
pp. 3877-3886
Author(s):  
Zhenhua Liang ◽  
Wenhe Liao ◽  
Xiang Zhang

During axial thrusting of a symmetric spinning spacecraft, misalignment and center-of-mass offset can cause unwanted body-fixed torques. The two-burn scheme is applied to eliminate velocity pointing error. Solutions for angular velocity, Euler angle, and inertial velocity with nonzero initial conditions are derived in a new form for axisymmetric spacecraft with constant mass. Simulations show that the solutions closely match numerical simulations and the two-burn scheme decrease the velocity pointing error obviously. Based on the solutions, the effect of two-burn scheme is analyzed. The results show that the spacecraft will obtain the minimum velocity pointing error if the burn and coast times are controlled accurately. Also, the two-burn scheme allows for a lower spin rate and the spacecraft can be maneuvered at nonzero initial conditions compared with the continuous thrust scheme.


2021 ◽  
Author(s):  
Dhanalakshmi R ◽  
Eswara Chaitanya D ◽  
Chandra Shaker Reddy P ◽  
Vijendra Babu D ◽  
Puneet Kumar Aggarwal ◽  
...  

Abstract The satellite communication is embellished constantly by providing information, ensuring security, and enables the communication among huge at a particular time efficiently. The satellite navigation helps in determining the people's location. The global development, natural disasters, change in climatic conditions, agriculture crop growth, etc. are monitored using satellite observation. Hence, the satellite includes detailed information data, it has to be protected confidentially. The field of the satellite is enhanced at an astonishing pace. Satellite data plays an important role in this modern world and hence, the onboard satellite data have to secure through the proper selection of error detection and estimation schema. The Extended Kalman Filter is widely used in the satellite system. EKF is utilized in this proposed model to detect the onboard pointing error such as attitude and orbit determination. An autonomous estimation of orbit position is possible through space-borne gravity. The information obtained through the observation of satellite data is compared with the accurate gravity model in detecting the error. The utilization of EKF reduces the dependence of the ground tracking system in satellite determination. The orbital altitude and orbital position are the most important challenges faced in the satellite determination system. The satellite model using the Extended Kalman Filter is a more apt method in estimating the orbital parameters. The errors in the linearization process are detected and this can be overcome through the proper selection of linear expansion point with EKF algorithmic model with the Jacobian matrix calculation. The results show that the EKF implementation helps in attaining better accuracy in comparison with other methodologies.


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