Aero-optical effects for starlight transmission in the high-speed flow field will reduce the accuracy of the star sensor on an aircraft.Numerical simulations for aero-optical effects usually require plenty of calculat...Aero-optical effects for starlight transmission in the high-speed flow field will reduce the accuracy of the star sensor on an aircraft.Numerical simulations for aero-optical effects usually require plenty of calculations,which cause difficulties when designing a celestial navigation system for a high-speed aircraft.In this study,an Aero-Optical Simulator For Starlight Transmission(AOSST)in the boundary layer is developed.It effectively reduces the computational burden compared to that of the widely used CFD simulation,and it achieves satisfactory accuracy.In this simulator,gas ellipsoids satisfying certain design rules are used to simulate coherent density structures in boundary layers.Design rules for the gas ellipsoids are found from published experimental and high-fidelity CFD simulation results.The generated wavefront distortion by AOSST is anchored with the scale law for aero-optical distortion in the boundary layer by determining some control parameters,which enables the simulator to output reliable results over a wide range of flight states.Four numerical examples are provided to verify the performance of AOSST.The results demonstrate that AOSST is able to simulate the directional dependence of aero-optical distortions in boundary layers,the variation trend of distorted wavefront shapes with Reynolds number,and the grayscale distribution on the disturbed star map.展开更多
The process of formation reconfiguration for close-range satellite formation should take into account the risk of collisions between satellites.To this end,this paper presents a method to rapidly generate low-thrust c...The process of formation reconfiguration for close-range satellite formation should take into account the risk of collisions between satellites.To this end,this paper presents a method to rapidly generate low-thrust collision-avoidance trajectories in the formation reconfiguration using Finite Fourier Series(FFS).The FFS method can rapidly generate the collision-avoidance threedimensional trajectory.The results obtained by the FFS method are used as an initial guess in the Gauss Pseudospectral Method(GPM)solver to verify the applicability of the results.Compared with the GPM method,the FFS method needs very little computing time to obtain the results with very little difference in performance index.To verify the effectiveness,the proposed method is tested and validated by a formation control testbed.Three satellite simulators in the testbed are used to simulate two-dimensional satellite formation reconfiguration.The simulation and experimental results show that the FFS method can rapidly generate trajectories and effectively reduce the risk of collision between satellites.This fast trajectory generation method has great significance for on-line,constantly satellite formation reconfiguration.展开更多
This paper presents the methods and results submitted by the winning team from Harbin Institute of Technology of the 10th China Trajectory Optimization Competition(CTOC10).The problem posed by CTOC10 requires explorin...This paper presents the methods and results submitted by the winning team from Harbin Institute of Technology of the 10th China Trajectory Optimization Competition(CTOC10).The problem posed by CTOC10 requires exploring the Jupiter system using a combined spacecraft.The exploration mission consists of the detection of Jupiter’s magnetic field and an exploration of the Galilean moons.The mission is completed through three steps:problem analysis,orbital design process,and data processing.The orbital design process is mainly divided into four parts,namely,repeating groundtrack orbit design,gravity-assisted orbit design,initial orbit parameter selection,and local optimization adjustment.The designed orbit is then evaluated using a heuristic optimization algorithm applied during the data processing.Finally,six full-coverage observations of Jupiter’s magnetic field are realized under the constraints of fuel and time.The final index of the submitted result is 357.8067.展开更多
基金supported by the National Defense PreResearch Foundation of China(No.JCKY2016601C005)the Science and Technology on Space Intelligent Control Laboratory of China(No.ZDSYS-2018-03)。
文摘Aero-optical effects for starlight transmission in the high-speed flow field will reduce the accuracy of the star sensor on an aircraft.Numerical simulations for aero-optical effects usually require plenty of calculations,which cause difficulties when designing a celestial navigation system for a high-speed aircraft.In this study,an Aero-Optical Simulator For Starlight Transmission(AOSST)in the boundary layer is developed.It effectively reduces the computational burden compared to that of the widely used CFD simulation,and it achieves satisfactory accuracy.In this simulator,gas ellipsoids satisfying certain design rules are used to simulate coherent density structures in boundary layers.Design rules for the gas ellipsoids are found from published experimental and high-fidelity CFD simulation results.The generated wavefront distortion by AOSST is anchored with the scale law for aero-optical distortion in the boundary layer by determining some control parameters,which enables the simulator to output reliable results over a wide range of flight states.Four numerical examples are provided to verify the performance of AOSST.The results demonstrate that AOSST is able to simulate the directional dependence of aero-optical distortions in boundary layers,the variation trend of distorted wavefront shapes with Reynolds number,and the grayscale distribution on the disturbed star map.
基金supported in part by the National Natural Science Foundation of China(Nos.11702072 and 11672093)。
文摘The process of formation reconfiguration for close-range satellite formation should take into account the risk of collisions between satellites.To this end,this paper presents a method to rapidly generate low-thrust collision-avoidance trajectories in the formation reconfiguration using Finite Fourier Series(FFS).The FFS method can rapidly generate the collision-avoidance threedimensional trajectory.The results obtained by the FFS method are used as an initial guess in the Gauss Pseudospectral Method(GPM)solver to verify the applicability of the results.Compared with the GPM method,the FFS method needs very little computing time to obtain the results with very little difference in performance index.To verify the effectiveness,the proposed method is tested and validated by a formation control testbed.Three satellite simulators in the testbed are used to simulate two-dimensional satellite formation reconfiguration.The simulation and experimental results show that the FFS method can rapidly generate trajectories and effectively reduce the risk of collision between satellites.This fast trajectory generation method has great significance for on-line,constantly satellite formation reconfiguration.
基金This work is supported in part by the National Natural Science Foundation of China(Nos.11772104 and 11702072).
文摘This paper presents the methods and results submitted by the winning team from Harbin Institute of Technology of the 10th China Trajectory Optimization Competition(CTOC10).The problem posed by CTOC10 requires exploring the Jupiter system using a combined spacecraft.The exploration mission consists of the detection of Jupiter’s magnetic field and an exploration of the Galilean moons.The mission is completed through three steps:problem analysis,orbital design process,and data processing.The orbital design process is mainly divided into four parts,namely,repeating groundtrack orbit design,gravity-assisted orbit design,initial orbit parameter selection,and local optimization adjustment.The designed orbit is then evaluated using a heuristic optimization algorithm applied during the data processing.Finally,six full-coverage observations of Jupiter’s magnetic field are realized under the constraints of fuel and time.The final index of the submitted result is 357.8067.
