In order to improve the star locating accuracy with non Gauss energy distribution for a star tracker, a new locating algorithm based on PSFC (point spread function correlation) was proposed. The new method has good anti noise performance, high accuracy and engineering realization. The PSFC locating algorithm is realized by using cross correlation definition and determining the maximum similarity of the measured star PSF and the star gray images of the star tracker. The measured star PSF are prepared before cross correlation computation by all the FOV subpixel measurements. The simulation results show that the accuracy of PSF correlation method considering high noise background can reach 0.034 pixels, and is higher than the traditional centroid method of 1 orders of magnitude , and is higher than the Gauss surface quasi legal of about 20%.

Highaccuracy autonomous navigation information can be obtained autonomously by pulsar navigation, including the position, velocity, attitude and time. The precision of the pulsar navigation can be mainly affected by the pulsar’s position error system, especially the uncertainty variance affect. Firstly, the uncertainty model of the pulsar navigation is presented. Secondly, the adaptive filter can reduce the unacceptable effect uncertainty variance. Numerical simulation demonstrates the effectiveness of the proposed approach.

This paper discusses the problem of rendezvous with a maneuver target spacecraft. Considering the maneuvers of the target spacecraft, as well as the external disturbance forces and the coupled states, a modified compress method is proposed and applied to establish the decoupled characteristic model based on the measurements of relative position. Then, a decoupled adaptive control method based on the characteristic model is presented to achieve the rendezvous of the two spacecraft. Finally, the simulation results demonstrate the effectiveness of the proposed method, and indicate that the method is better than the traditional PD control.

Singularity problem of single gimbal control moment gyros (SGCMGs) always exists in practical applications. In this paper singularity index is regarded as the path constraint, and gauss pseudospectral method is used in optimizing trajectory. Then a group of nonsingularity gimbal angles and gimbal rates can be obtained as open loop control commands. Considering the effect of the initial attitude errors and external disturbance, reaction wheels (RWs) are introduced to modify the tracking errors and a feedback control law is designed based on Lyapunov stability method. Numerical simulation suggests that with the help of RWs, the nonsingularity SGCMGs commands are also executed strictly and the optimal trajectory can be tracked well under the influence of external disturbance.

The conical earth sensor （CES） is a key measuring instrument of spacecraft． The preamplifier of CES has high gain and low noise  characteristics． By simulation analysis, we find out that different parameters of cable and device remarkably affect the circuit’s stability． Based on this, an example of circuit stability problem is presented． To solve this problem, a kind of frequency compensation method is carried out． To confirm this method validity, a series of ground experiments including calibration test, thermal vacuum test and EMC test are designed and performed．

Accurate dynamics characteristics are important for rotary inertia identification. Considering the effect of solar cell array rotation in dynamics, a method of inertia identification is proposed, which is applied to identify the body inertia and solar cell array inertia simultaneously. Thinking of the coupling between the variables, the optimized identification model with constraint is deduced based on the modeled multibody attitude dynamics. The precise solution is achieved via the algorithm of constraint least squares. Finally, the feasibility of the identification method is verified by simulation and calculation.

Regarding the shutter of space imager as the research background, the advantages and disadvantages of different types of shutters are introduced. The rotarydisc shutter is selected as the research object. Starting from the mode of exposure, the control strategy of shutter is investigated. The reason for selecting PMSM motor is analyzed, and a controller based on Digital Signal Processor (DSP) is designed. Furthermore, the maximum error of exposure time is less than 3.0%, which meets the performance requirements of telescope imager.

For highagility and highprecision attitude maneuver of remote sensing satellites, the control moment gyroscope (CMG) is expected to supply more accurate torque, which means the disturbance torque acting on its gimbal axis should be minimized to reduce the fluctuation of the gimbal speed. The torque generated by the wheel imbalance is analyzed, and the gimbal system model is built. To improve the gimbal speed stability, an iterative learning control (ILC) module is inserted into the PID gimbal control system. The proposed control system is evaluated via system simulation, and the results demonstrate that the ILC algorithm can minimize the fluctuating torque effectively, which significantly improves the precision of the CMG output torque.

In order to improve the accuracy of gyro constantcurrent source, a  compensation method of gyro constantcurrent source is proposed based on back propagation (BP) neural network. Firstly, with BP neural network, a nonlinear steadystate model that represents the relationship between the control input and the output of gyro constantcurrent source is trained. The model is used to estimate the output deviation of constantcurrent source. Secondly, a compensation criterion is confirmed, which is used to determine whether or not to modify the control command. Once the constantcurrent output deviation exceeds the margin, a certain proportion deviation is added up to the control command. Finally, the HIL(hardwareintheloop) simulation is carried out. The results show that the proposed method improves the output accuracy of the gyro constantcurrent greatly compared with the conventional piecewise linear correction method.

To investigate the relationship between the inject pressure and the spray atomization characteristics, a series tests are taken on a bicentrifugal swirl injector, which works in different injection pressures. The generation and evolution process of the spray are experimentally studied by highspeed photography trials. And the PDA (Phase Doppler Anemometry) tests focus on the stable spray characteristics. On the basis of the experimental results, an equation is developed via nonlinear fitting calculation. The test results show that the injector has good atomization characteristics. Increasing injection pressure makes the spray form more quickly and the spray cone angle becomes larger. The equation can use for predicting the D32 of this bicentrifugal swirl injector in different situations, which could provide data for designer.

A new timesynchronization algorithm is presented, which combines software synchronization and hardware synchronization. Time synchronization is achieved via information interchange between two computers. With this algorithm, initial time synchronization is established among different standalone computers after initial synchronizing process. And then the systemmaintainsthe synchronized state. If one of the computers falls out of the synchronism due to temporary fault, it can autonomously synchronize with other computers with the algorithm. This algorithm is applicable for the time synchronization of multiple hot redundant onboard computers, and improvesthe selfrecovery ability of the system.