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Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT 期刊论文 OAI收割
Astrophysics and Space Science, 2020, 卷号: 365, 页码: 158
作者: HXMT

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Insight-HXMT Geant4 simulation Background observation Astrophysics - Instrumentation and Methods for Astrophysics Abstract: Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, in-orbit backgrounds of these three telescopes had been estimated through Geant4 simulation, in order to investigate the instrument performance and the achievement of scientific goals. In this work, these simulated backgrounds are compared with in-orbit observations. Good agreements are shown for all three telescopes. For HE, (1) the deviation of the simulated background rate after two years of operation in space is 5 % from the observation (2) the total background spectrum and the relative abundance of the 67 keV line show long-term increases both in simulations and observations. For ME, (1) the deviation of simulated background rate is within 15 % from the observation, and (2) there are no obvious long-term increase features in the background spectra of simulations and observations. For LE, the background level given by simulations is also consistent with observations. The consistencies of these comparisons validate that the Insight-HXMT mass model, i.e., space environment components and models adopted, physics processes selected, and detector constructions built, is reasonable. However, the line features at 7.5 and 8.0 keV, which are obvious in the observed spectra of LE, are not evident in simulations. This might result from uncertainties in the LE constructions.

In-orbit Demonstration of X-Ray Pulsar Navigation with the Insight-HXMT Satellite 期刊论文 OAI收割
The Astrophysical Journal Supplement Series, 2019, 卷号: 244, 页码: 1
作者: HXMT

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pulsars: general techniques: miscellaneous Astrophysics - Instrumentation and Methods for Astrophysics Abstract: In this work, we report the in-orbit demonstration of X-ray pulsar navigation with Insight-Hard X-ray Modulation Telescope (Insight-HXMT) Satellite, which was launched on 2017 June 15. The new pulsar navigation method Significance Enhancement of Pulse-profile with Orbit-dynamics is adopted to determine the orbit with observations of only one pulsar. In this test, the Crab pulsar is chosen and observed by Insight-HXMT from 2017 August 31 to September 5. Using the five-day long observation data, the orbit of Insight-HXMT is determined successfully with the three telescopes onboard: High Energy X-ray Telescope, Medium Energy X-ray Telescope, and Low Energy X-ray Telescope, respectively. By combining all the data, the position and velocity of the Insight-HXMT are pinpointed to within 10 km (3ҩ and 10 m s^-1 (3ҩ, respectively.

Integrated optimization method for coupling parametrization design of complex space system (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on System Science, Engineering Design and Manufacturing Informatization, ICSEM 2012, October 20, 2012 - October 21, 2012, Chengdu, China
作者: Han C.-S.; Wen M.

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This paper investigates the problem of optimization method for coupling parametrization design of complex space system. The objective is to develop an integrated optimization framework to design complex space system. An improved collaborative optimization (ICO) strategy for complex design using hybrid optimization algorithm is proposed which associates genetic algorithm (GA) with tabu search (TS). A multi-objective function with penalty terms for the systemlevel optimization and a relax factor for the subsystem optimization are adopted which can avoid unsolvability or converging difficulty. The results demonstrate the applicability and effectiveness of the proposed design methodology. 2012 IEEE.

Design of high speed and parallel compression system used in the big area CCD of high frame frequency (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Precision Engineering and Non-Traditional Machining, PENTM 2011, December 9, 2011 - December 11, 2011, Xi'an, China
作者: Li G.-N.; Jin L.-X.; Zhang R.-F.; Wang W.-H.; Li G.-N.

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According to the area CCD camera of characteristics such as high resolution capacity and high frame frequency this paper puts forward a high speed and parallel image compression system of high integration degree. Firstly according to the work principle of the area CCD FPGA is adopted to realize the timing driving and multichannel and parallel analog signal handling to raise the export frame frequency of the area CCD. Secondly with an image compression scheme based on FPGA embedded processor MicroBlaze and ADV212 compression chip real time image compression and the high speed area CCD are realized. Finally by detecting the analog signal of the area CCD output the real time compression of the big area CCD image is carried out in different compression ratios and the compression performance is analyzed. Experiment result shows that this scheme can realize real time image compression with the biggest data rate of 520Mbps. When compression bit ratio is 0.15 the signal-to-noise ratio of peak value can reach 36 dB. Image collection and image compression are integrated which reduces the data transmission between them and improves systematic integration degree.

AUTONOMOUS INTEGRATED NAVIGATION USING X-RAY PULSARS AND ASTEROIDS 会议论文 OAI收割
63rd International Astronautical Congress 2012, IAC 2012, Naples, Italy, 2012
Yang Chengwei; Gao Dong; Zheng Jianhua

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To improve the navigation performance of the spacecraft during interplanetary cruise a novel integrated navigation system is proposed. For X-ray pulsar navigation (XNAV) is a hot and prospective research subject and the optical navigation using asteroids is practical in space engineering we designed an autonomous navigation system using one X-ray detector and one navigation camera. The measurement models of the XNAV based on the time difference of arrival and the optical navigation based on the images of asteroids are presented. To enhance practicality the X-ray pulsars and asteroids are observed by turns. The batch least square filter used by Deep Space I is adopted to estimate the system state. The numerical simulation results show that the integrated navigation is feasible on the interplanetary cruise orbit. Moreover compared with the XNAV and the optical navigation the integrated navigation system can provide higher navigation performance.

A strong coupled CFD-CSD method on computational aeroelastity (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
Xi R.; Jia H.

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In this paper a strong coupled CFD-CSD method is developed to simulate the aeroelastic phenomena. The CFD solver is based on the finite-volume algorithm for the Navier-Stokes equations on unstructured grid. The CSD solver solves the aeroelastic governing equations in the modal space. Their coupling is realized by a dual-time method. The spring-based smoothing method is adopted to deform and regenerate the aerodynamic grid. Two test cases are selected to validate the authors' method for static and dynamic aeroelastity .The results of the simulation for the static aeroelastic problems of a missile wing show that the Lift Coefficient and Drag Coefficient are severally 7% and 5% lower than those don't consider the elasticity of the wing. The results for the flutter boundary prediction of the AGARD 445.6 wing have been proved much closer to the experiment than using the DLM. This method can describe the effects of fluid viscosity more exactly for highly nonlinear transonic flight conditions. The calculation has proved reliable in the subsonic regime but not accurate enough in the supersonic regime. 2011 IEEE.

Design of motion adjusting system for space camera based on ultrasonic motor (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
作者: Sun Z.

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Drift angle is a transverse intersection angle of vector of image motion of the space camera. Adjusting the angle could reduce the influence on image quality. Ultrasonic motor (USM) is a new type of actuator using ultrasonic wave stimulated by piezoelectric ceramics. They have many advantages in comparison with conventional electromagnetic motors. In this paper some improvement was designed for control system of drift adjusting mechanism. Based on ultrasonic motor T-60 was designed the drift adjusting system which is composed of the drift adjusting mechanical frame the ultrasonic motor the driver of Ultrasonic Motor the photoelectric encoder and the drift adjusting controller. The TMS320F28335 DSP was adopted as the calculation and control processor photoelectric encoder was used as sensor of position closed loop system and the voltage driving circuit designed as generator of ultrasonic wave. It was built the mathematic model of drive circuit of the ultrasonic motor T-60 using matlab modules. In order to verify the validity of the drift adjusting system was introduced the source of the disturbance and made simulation analysis. It designed the control systems of motor drive for drift adjusting system with the improved PID control. The drift angle adjusting system has such advantages as the small space simple configuration high position control precision fine repeatability self locking property and low powers. It showed that the system could accomplish the mission of drift angle adjusting excellent. 2011 SPIE.

Study on the servo system of large telescope based on the internal model pid control strategy (EI CONFERENCE) 会议论文 OAI收割
IEEE 2011 10th International Conference on Electronic Measurement and Instruments, ICEMI 2011, August 16, 2011 - August 18, 2011, Chengdu, China
Li H.

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This paper developed the internal model PID control for large telescope control system considerations in more parameters adjustment in servo control loop at present. The large electro-optic telescope system belongs to a big inertia system. This simplifies the debug process the feasibility and robustability are also verified by the analyses and simulation results that satisfy the high precision demand. The practicability of this algorithm is verified in an actual project that only two parameters need adjusted. The application shows that this system runs stably with high accuracy. The technology and methods adopted in the system are practical and worthy of using abroad. 2011 IEEE.

Compensation of moire fringe sinusoidal deviation in photoelectrical encoder based on tunable filter (EI CONFERENCE) 会议论文 OAI收割
2011 Symposium on Photonics and Optoelectronics, SOPO 2011, May 16, 2011 - May 18, 2011, Wuhan, China
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

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In order to improve the precision of the absolute photoelectrical encoder a compensating method is put forward which restrains the harmonics in moire fringe signal. After analyzing the relationship between the subdividing error and the sinusoidal index a low-pass digital filter which can make the moire signal satisfy the need of 1024 subdivision is designed. Considering with the fundamental frequency varies with the rotating speed of encoder the tunable filter is adopted whose cutoff frequency is calculated according to the coarse information of the encoder. The simulating results show that the proposed method can improve the sinusoidal index especially at high rotating speed. At last the compensating algorithm is implemented in the terminal of satellite optical communication which needs high resolution. The experimental results show indicate that the developed method is feasible. 2011 IEEE.

Adaptive Wiener filtering with Gaussian fitted point spread function in image restoration (EI CONFERENCE) 会议论文 OAI收割
2011 IEEE 2nd International Conference on Software Engineering and Service Science, ICSESS 2011, July 15, 2011 - July 17, 2011, Beijing, China
作者: Yang L.; Zhang X.; Zhang X.; Zhang X.; Yang L.

收藏 | 浏览/下载：45/0 | 提交时间：2013/03/25

In the imaging process of the space remote sensing camera there was degradation phenomenon in the acquired images. In order to reduce the image blur caused by the degradation the remote sensing images were restored to give prominence to the characteristic objects in the images. First the frequency-domain notch filter was adopted to remove strip noises in the images. Then using the ground characters with the knife-edge shape in the images the point spread function of the imaging system was estimated. In order to improve the accuracy the estimated point spread function was corrected with Gaussian fitting method. Finally the images were restored using the adaptive Wiener filtering with the fitted point spread function. Experimental results of the real remote sensing images showed that almost all strip noises in the images were eliminated. After the denoised images were restored its variance and its gray mean gradient increased also its laplacian gradient increased. Restoration with Gaussian fitted point spread function is beneficial to interpreting and analyzing the remote sensing images. After restoration the blur phenomenon of the images is reduced. The characters are highlighted and the visual effect of the images is clearer. 2011 IEEE.