In order to reduce the number of jet unloading of satellites in orbit, save propellant and prolong the service life of satellites, the angular momentum management of zero momentum satellites and V-wheel bias momentum satellites in geostationary orbit is researched. According to the characteristics of the satellite angular momentum evolution, the angular momentum management methods for two types of satellites are presented, and the optimized jet unloading strategy is proposed. Based on the above research, theoretical analysis and simulation verification of abnormal unloading of in orbit satellites are carried out, and solutions are proposed. In orbit experiments show that the optimized jet unloading strategy can significantly reduce the number of satellite unloading, which verifies the correctness of the strategy.

For the satellites equipped with multiple star sensors, there will be many problems such as too many filtering constant gain matrices and complex system when using conventional CGKF (constant gain Kalman filtering) method to determine the attitude. In order to simplify the filtering system and unify the constant gain matrix, a satellite attitude determination method based on virtual star sensor is proposed in this paper. Firstly, with small calculation amount, an algorithm of time lag compensation and relative reference calibration of star sensor is presented, which is suitable for onorbit realtime calculation of onboard computer. The output data of star sensor is unified to the current star time and the measuring reference of star sensor is unified. Secondly, the output data of virtual star sensor(the installation matrix is a unit matrix) is constructed based on the output data of single star sensor/dual star sensors, and a unified constant gain matrix is designed to determine the attitude. The simulation results show that the attitude determination accuracy of the proposed method is equivalent to that of the conventional CGKF method, therefore the effectiveness of the proposed method is verified. The proposed method unifies the constant gain matrix, saves a lot of onboard computer resources, and has important engineering application value.

In order to establish an accurate model of the all electric propulsion satellite, design an attitude orbit control method and improve the satellite control accuracy, the dynamics modeling of the all electric propulsion satellite with deployable thruster point assembly mechanism (TPAM) is studied. The model of the four joint deployable TPAM is established, and the electric thrust and torque models based on the configuration of TPAM are derived. On this basis, the attitude orbit dynamics equation of the satellite is established. The model can be used to describe the attitude motion state and orbit change of the all electric propulsion satellite, which can accurately reflect the motion performance of the satellite. The model has been applied in the development of the APSTAR 6E satellite. The simulation results show that the dynamic simulation results of all electric propulsion satellite via the model accord with the test and analysis results, and the control effect of the APSTAR 6E in orbit is consistent with the expectation, which verifies the validity of the model.

The pose estimation of space noncooperative targets based on point cloud is often affected by noise. In order to improve the accuracy and robustness of pose estimation for space noncooperative targets, a combination algorithm of truncated least squares estimation and semidefinite relaxation (TEASER) and iterative closest point (ICP) is proposed in this paper. The method includes two parts: coarse registration and fine registration. In coarse registration, the matching pair is found by the signature of histogram of orientation (SHOT) of local point cloud and model point cloud, and then the initial pose is solved by TEASER. In fine registration, ICP is used to optimize the pose estimation results. The Beidou satellite simulation experiment shows that when the noise standard deviation is 3 times the resolution of the point cloud, the translation error of the periodic key frame registration method based on TEASER is less than 3.33cm, and the rotation error is less than 2.18° in the pose estimation of continuous frames. Compared with the traditional ICP method, the average translation error and average rotation error are reduced. The results show that the proposed pose estimation method has good accuracy and robustness.

In order to improve the accuracy of multivariable prediction of solar array and solve cyclical volatility and growth of telemetry parameters of solar array couple with each other, a multivariable prediction algorithm of solar array based on STL Prophet Informer model was proposed. The algorithm firstly uses the seasonal and trend decomposition procedure based on loess to decompose multiple parameters of the solar array into trend components, periodic components and residual components. Then Prophet is used to predict the trend component, and Informer model is used to predict the periodic component and residual component. Finally, the predicted values of the total solar array parameters are obtained by adding the predicted results of each component. Taking the actual telemetry data of a satellite solar array as an example, this paper proposes that the various error evaluation indexes of the algorithm are significantly reduced compared with the single Informer model and LSTM model, etc. Applying the combined prediction model to the multivariable parameter prediction of the satellite battery array can improve the accuracy of parameter prediction and improve the autonomous operation performance of the satellite.

Within the current domain of space situational awareness, the traditional frame based visual sensors have certain limitations in detection and tracking of swiftly moving space point objects, struggling to meet the escalating demands of tasks. Thus, neuromorphic event based cameras, with their high temporal resolution and dynamic range, emerge as a focal point of research. A space point object tracking method is proposed based on asynchronous event stream. Initially, due to the substantial noise present in the raw event stream data, noise is filtered out through a single layer spiking neuron, yielding potential objects. Subsequently, these candidates are persistently tracked using nearest neighbor motion trajectory association, which elucidates the movement trajectories of each. Ultimately, spurious candidates are eliminated through feature weight false alarm filtering, retaining the genuine motion trajectories of space point objects. During the experimental phase, the CeleX V event camera is employed to measure event data and the public space object event dataset (EBSSA dataset) is utilized to substantiate the efficacy of the proposed algorithm. Notably, in terms of sensitivity and Informedness content, it possesses distinct advantages over the event based space object tracking methods mentioned within the literature, affirming that the asynchronous event stream based tracking can accurately detect one or multiple space point objects from raw event stream data and capture their motion trajectories.

Visual localization is a fundamental task in computer vision, which is widely used in UAV control, surveillance system and remote sensing. In GNSS denied cases, visual localization using existing image references is an alternative navigation method for UAVs. However, due to the scene differences caused by changes of weather, season and illumination, the accuracy of visual localization of UAV images can hardly be guaranteed, especially when the UAV is flying close to the ground. In this paper, a visual localization framework with image synthesis is proposed to solve these problems. The proposed framework combines shadow mappingbased texture fusion and deep convolutional inpainting network to synthesize novel view images. These synthesized images can be used as additional reference data to solve the appearance change and large parallax problem, by improving the accuracy of 2D 3D feature mapping and registration in the stage of pose estimation. Experimental results show that the performance of proposed image synthesis is better than traditional stitching methods, in terms of visualization, number of matches, confidence and localization accuracy. It is proved that the proposed method can support UVA visual localization with large appearance changes.

Due to its characteristics of being thin walled and flexible, the dynamics performance parameters of flat solar sails for deployable thin film structures are rather complex. In order to comprehensively and accurately understand the impact of the large flexible solar sail dynamics on the attitude control performance of new hundred kilogram class low Earth orbit satellites, the ANCF (absolute node coordinate formulation) beam model and ANCF membrane elements are used to construct the primary flexible appendages. A dynamic model of large space deployable structures is established based on the predeformation of the beams. With the established dynamic model, complex space environmental disturbances including solar radiation pressure, aerodynamic drag, gravity gradient torque and geomagnetic torque are comprehensively considered. The CMIF (complex modal indicator function) method is employed to identify the modal parameters of the flat solar sail in orbit. Comparison between the identification results and simulation analysis results show that the CMIF method can effectively identify the loworder natural modes of deployable flat solar sails, laying a theoretical foundation for their engineering implementation.

Aiming at the problems of high precision attitude control and active vibration suppression of flexible spacecraft with uncertain model parameters and external interference, a simple ACPD (auto coupling proportional derivative) control method was proposed based on the ACPID (auto coupling proportional integral derivative) control theory. The known and unknown internal dynamics and external disturbances of the attitude motion of a flexible spacecraft are defined as a total disturbance, which is equivalent mapped to a second order linear disturbance system. Based on this, the controlled error system under the combined total disturbance reversed phase excitation is constructed, and the ACPD attitude controller and the ACPD active vibration controller are designed respectively according to the ACPID control theory. The robust stability and antidisturbance robustness of each system are analyzed. The simulation results show that the ACPD attitude controller has good tracking performance for the attitude angle instruction, and the ACPD active vibration controller can effectively suppress the vibration of flexible accessories.

Aiming to SRS(spherical roll spherical joint) manipulator, an inverse kinematics resolution method based on arm angle planning is proposed in this paper. This method considers arm angle, which is planned according to the target place, as a redundant parameter. According to the geometry of the manipulator, the size of each joint is figured out when arm angle and terminal location are known. Meanwhile, aiming to the probable singular position of arm angle during the movement of the manipulator, inverse kinematics is solved by introducing the constraint of elbow position. The proposed inverse kinematics is verified by the co-simulation of UG Simulink and physical experiment. When the manipulator is located in the shoulder singular position, this method can avoid the countless results generated by joint parameterization. In the physical experiment of capturing and releasing under the gravity unloading environment, the presented methods in this paper can effectively solve the problem of singular solution under the limited motion space.

In view of the development needs of standardization and generalization of satellite simulation technology, a tool architecture is constructed that can support satellite digital simulation based on FMI (functional mock-up interface) and model reuse technology. On this basis, the satellite digital simulation platform is designed based on the idea of modularization, and the FMI standard wrapping method of Simulink and C/C++ model is given. Using the satellite digital simulation platform, the multi satellite operation simulation scene is built. Through the remote process call technology, the simulation process data is pushed to the visualization platform to complete the visual display of the satellite operation scene. The simulation case shows that the satellite simulation platform can monitor the operation state and change the trend of the model. At the same time, the scene visualization platform can dynamically display the operation orbit, attitude and other data of the satellite in real time.

On orbit service and maintenance is an important development direction of space technology in the future. In orbit services such as fuel refueling, cutting and operating wires, screwing caps, and disassembling valves have the characteristics of light load, close range sensing, precise positioning, and grasping. For these application scenarios, this article uses lightweight robotic arm Kinova and built-in RGBD (red, green, blue, depth) cameras for perception, positioning, grasping, and completing ground verification experiments to provide theoretical support for in orbit services. This article first introduces the research background of the robotic arm grasping system and describes the development platform and its characteristics. Secondly, introduce camera calibration, color camera and depth camera registration principles, and use the TF (transform) tree of ROS (robot operating system) to obtain three dimensional coordinates. A color space image segmentation method based on HSV (Hue, Saturation, Value) is proposed for specific captured objects, for object detection, segmentation, and spatial positioning. Finally, the experimental stage involves the robotic arm completing the target capture process based on the visual positioning results. The effectiveness of combining color space image segmentation methods with depth maps for localization has been demonstrated, providing theoretical validation for in orbit services.