Under the background of rendezvous and docking of vehicles in the approach phase in space, an equivalent mechanical model for liquid sloshing under zerogravity and microgravity is investigated. Based on the model built in automatic transfer vehicle (ATV), a springmass equivalent mechanical model applicable to liquid in spherical tanks under zero/microgravity is proposed. Parameters of this model are obtained by combining the method of parameter identification through CFD computation with traditional modeling method used for liquid sloshing in normal gravity. In this paper, introduction to this model is given first, then the approach to parameters of this model is described, and solution equations for slosh forces and moments are derived based on the principle of virtue power. Feasibility and accuracy of this modeling method are analyzed by comparing the slosh forces and moments to results of the computational fluid dynamics (CFD) software Flow3d.

A relative estimation method of noncooperative spacecraft is proposed based on stereo vision with unknown geometric parameters. The image of target is smoothed and thinned by Canny operator. Edge segments, represented by linkedlists, are classified into straight segments and arc segments. Rectangle features and circle features are recognized from straight and arc segments respectively. Algorithm for relative position and attitude estimation of rectangle is designed based on the property of vanishing point of parallel lines. We also presented a novel and efficient method of estimating relative position and attitude and radius of circle. At the end, real images are tested to validate the proposed algorithms.

The discrepancies between impulsive thrust model and continuous thrust model have greatly limited the application of impulsive strategy on spacecraft rendezvous trajectory engineering. Based on Lambert theorem and genetic algorithm, an optimal impulsive rendezvous trajectory is designed. According to the results, an engineering realization method is implemented via iterative guidance algorithm. The simulation results show that the method is effective.

To raise the precision of post attitude determination, the rauch tung striebel (RTS) filter algorithm is introduced based on EKF. Currently the errors are usually used as state variables in EKF to determine the attitude. Via calculating the data obtained from EKF, the RTS smooth filter is successfully applied to post attitude determination, and at the same time, the singularity of the error covariance matrix is evitable. The simulation results indicate that the RTS smooth filter algorithm is significantly better than EKF in post attitude determination.

An error compensation algorithm based on distance ranging is proposed for a class of autonomous navigation problems of spacecraft formation. It uses a high precision relative measuring method with less position data. The error compensation algorithm is given to prevent the local instability of traditional EKF method. A consensus distributed EKF algorithm is also given in this paper, which combines consensus theory and distributed kalman filter. The system is regarded as a network. A simulation result proves that this algorithm can prevent high frequency noise and has a high accuracy.

To deal with the flexible parameters uncertainties and external torque disturbance problems of satellites with large flexible appendages, a robust Hinfinity feedback multiinput, multioutput (MIMO) controller is proposed based on linear matrix inequalities (LMI). Parameters perturbations that caused by solar paddles rotating towards the sun and antenna’s expanding process are considered in the coupled dynamics of satellite. The proposed robust controller guarantees robust stability against the a forementioned higher vibration modes and modal parameters uncertainties for a linear parameter varying (LPV) MIMO system. Moreover, it is simple and suitable for engineering practice. The simulation results show that the given controller provides rapid stabilization for threeaxis attitude control, and is more robust than the typical PID controller in vibration and disturbance suppression.

To satisfy the ground verification request of the ZY3 satellite’s high precision control subsystem, a whole set of verification system is designed. The system can ensure the complicated verification under the test status, including the control subsystem’s outer interface, equipmentrelated trouble check and switch, system function, implement of attitude control performance, and inorbit fault prevention plan. After the launch of ZY3 satellite, the control subsystem works stably in orbit. Moreover, the attitude control precision and the time precision both satisfy the satellite index.

Based on lightofsight (LOS) vector measurement, an autonomous navigation algorithm is developed to realize the first autonomous navigation mission of China during the phase of approaching Mars. On the basis of orbital dynamics and the geometric relationship between Mars and the spacecraft, the equation with respect to the norm of the position vector is derived in detail, with the Mars LOS serving as the only measurement. The equations of position vector and velocity vector are further developed. Finally, simulations and comparative analysis on the autonomous navigation algorithm are directed under orbits of ellipse and hyperbola respectively.

Determination of the relative states is the primary and important guarantee for normal operation of microsatellite formation. With the miniaturization and lowcost spaceborne GPS receiver, the accuracy of orbit determination is low. In order to solve this problem, a method of correcting the formation relative orbit is given with only intersatellite ranging information used. Intersatellite ranging information is introduced and the extended Kalman filter is used to enhance the estimation accuracy of the relative orbit. The numerical simulation results show the validity of this approach.

During the process of hardware/software codesign of onboard computer, power estimation of processor is an essential problem. The existing methods involving power estimation of processor mainly aim at ARM and DSP processors without the ability of dealing with LEON3 processor. To cope with this problem, based on the functional lever power analysis, a method is proposed to extract parameters from C code. At the same time, the sequential minimal optimization algorithm of support vector regression is improved to enhance the model precision. In the experiment section, the predicting precision of the proposed method is verified by some common algorithms programmed in C language. The results show that the predicting error is less than 3%, and the precision can meet the requirement for hardware/software codesign of onboard computer.

Considering the new requirements for sensorless permanent magnet brushless DC motor in a liquid floated gyro, a new phaselocked loop steadyspeed control system is presented based on complex programmable logic device (CPLD) and ML4411.The back electromotive force (backEMF) detection, commutation and power drive are realized by the chip ML4411. The zerospeed start control is realized by a CPLD chip, so does the generation of the speed reference. The control accuracy is greatly improved via the application of the twolevel phaselocked loop (PLL) technique. The requirements for the performance of the gyro are satisfied with the proposed control system in a motor speed test, which provides an effective method to improve the performance of the gyro.

For the feasibility from traditional cable to wireless for intrasatellite network, the requirements of the intrasatellite communications are analyzed. A star topology network based on ZigBee is designed and realized, and the wireless communication test is carried out. The test results show that this ZigBeebased intrasatellite network can achieve the network requirements for slow data rate, closedistance sensors and actuator, and it is stable for communication.