Wang S.,Huazhong Institute of Electro Optics |
Zeng X.H.,Huazhong Institute of Electro Optics Wuhan
Applied Mechanics and Materials | Year: 2013
This paper has described the status and role of the strapdown mirror control technology. It has analyzed the emphasis and difficulty in the study. In order to achieve higher system reliability and improve performance and eliminate all kinds of error of strapdown stable platform process what are stabilization while reducing the volume. In-depth analysis of the swing ship is on strapdown platform and mirror effect. The boat rocking and the sight stabilization mathematical model of mirror rotating. A study on the simulation what uses the MATLAB. By establishing the model of boat rocking, what analysis of the swing's influence on the mirror steady accuracy and tracking accuracy. The existing stable servo control and principle has been detailed analysis. Through the simulation studies what compared their advantages and disadvantages. Also it has studied the coning error compensation method and the kalman filtering what influenced on the accuracy of strapdown mirror control system. © (2013) Trans Tech Publications, Switzerland.
Zheng J.,Wuhan University |
Li Z.,Huazhong Institute of Electro Optics |
Gao L.,Huazhong University of Science and Technology |
Jiang G.,Wuhan University
Engineering Computations (Swansea, Wales) | Year: 2016
Purpose - The purpose of this paper is to efficiently use as few sample points as possible to get a sufficiently explored design space and an accurate optimum for adaptive metamodel-based design optimization (AMBDO). Design/methodology/approach - A parameterized lower confidence bounding (PLCB) scheme is proposed in which a cooling strategy is introduced to guarantee the balance between exploitation and exploration by varying weights of the predicting error and optimum of a metamodel. The proposed scheme is investigated by a set of test functions and a structural optimization problem, in which PLCB with four kinds of cooling control functions are studied. Moreover, other infill criteria (such as expected improvement and its extension versions) are taken into comparison. Findings - Results show that the proposed PLCB (especially PLCB with the first cooling control function) based AMBDO method can find the optimum with fewer evaluations and maintain good accuracy, which means the proposed PLCB contributes to the excellent efficiency and accuracy in finding global optimal solutions. Originality/value - The parameterized version of the lower confidence bound metric is proposed for AMBDO, typically used in the context of adaptive sampling in efficient global optimization. © 2016 Emerald Group Publishing Limited.
Li L.,Harbin Engineering University |
Li L.,CAS Academy of Opto Electronics |
Yang W.,Harbin Engineering University |
Yang W.,Huazhong Institute of Electro Optics |
And 2 more authors.
Chinese Control Conference, CCC | Year: 2015
Carrier-Smoothed-Code (CSC) can effectively suppress the multipath effect and receiver noise in the code-based differential positioning, which is widely adopted by the Ground Based Augmentation System (GBAS). However, the accuracy of smoothed code can be degraded significantly by the Code-Carrier-Divergence (CCD) effect. The CCD monitoring technology of for BeiDou Satellite System (BDS) is still under developing. This paper analyzed and compared two methods of CCD monitoring in GPS and BDS, respectively. Based on the CCD monitoring results, it was found that the tow-order linear invariant filter is better for CCD in terms of detection time and estimation accuracy. With the given constant false alarm rate, CCD detection threshold can be obtained. Furthermore, the sigma-inflation method is used to compensate the non-perfect distribution of the constructed test statistics. The real-world experiment of GPS and BeiDou is implemented to make a comparative analysis. The experimental result shows that the two-order detection method is more applicable to BDS due to the better availability. © 2015 Technical Committee on Control Theory, Chinese Association of Automation.
Luo Y.,Zhejiang University |
Bai J.,Zhejiang University |
Zhou X.,Zhejiang University |
Huang X.,Zhejiang University |
And 3 more authors.
Optics Express | Year: 2016
An inevitable problem of Panoramic Annular Lens (PAL) System is the blind area in the central part of image plane, which vastly reduces the pixel efficiency of detector. Here we present a design of PAL system based on dichroic filter, which can combine two channels of rays in different bands and image them on the same detector. The dichroic filter in this paper is designed to make ultraviolet rays reflect and visible rays transmit, and the ultraviolet rays are imaged on the PAL imaging area while the visible rays are imaged on the blind area of conventional PAL image plane. In order to image both bands of rays on the same plane, we add a correcting lens group in front of PAL system. As a result, the FOV of ultraviolet channel is ranging from 30°∼90° and the one of visible channel is ranging from 0°∼10°. © 2016 Optical Society of America.
Du Y.,Huazhong Institute of Electro Optics |
Liu A.D.,Wuhan National Laboratory for Optoelectronics
Applied Mechanics and Materials | Year: 2013
A noncontacting velocimetry technique based on line scan sensor arrays is proposed. Auto-correlation method is the mainly velocity measurement algorithm before. In my research, I will introduce a novel spatial filtering method based on line scan sensor for noncontacting velocimetry. When used for measuring a vehicle's velocity, the variation of the distance between the sensor and the road may cause a primary source of errors. In this paper, an adaptive Double-channel optical system is recommended to eliminate the errors, and we verify the effectiveness of the design in theory. © (2013) Trans Tech Publications, Switzerland.
Mao H.,Huazhong Institute of Electro Optics |
Liu A.,Huazhong Institute of Electro Optics |
Wang L.,Huazhong Institute of Electro Optics
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2014
A new star recognition method based on hybrid particle swarm algorithm was developed to increase recognition speed and success rate for large field high sensitivity star sensors. Firstly, several candidate recognition main stars were determined with the gray information. Then a circle was drawn with the given circle radius, and all stars in the circle were selected to constitute a characteristics data collection. Hybrid particle swarm algorithm was used for fast path optimization to construct recognition characteristics. Finally, the optimal path length was used for indexing to search matching star, and preceding three star angular distance and magnitude in the optimal path were used for matching recognition to enhance recognition speed and success rate. Experimental results show that, compared with existing recognition methods, star recognition method based on hybrid particle swarm optimization algorithm has a higher recognition rate, good real-time and robustness to noise, and it requires small star database capacity. ©, 2014, Chinese Society of Astronautics. All right reserved.
Mao H.,Huazhong Institute of Electro Optics |
Liu A.,Huazhong Institute of Electro Optics
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2013
According to the targets with different size s, different sizes of the filter modes need to be selected in image processing. Multiple targets with different sizes may be existed in an image, or the size of the target is not known at all in ATR system sometimes. Therefore, the filter with different sizes will be used to test in those situations. How to get the best results of the different filters together is a very important key technology in image processing. A method based on the improved DS evidence theory was presented. The experiment results indicate that the proposed method could well extract different sizes targets in an image.
Yang X.,Huazhong Institute of Electro Optics |
Geng A.,Huazhong Institute of Electro Optics
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012
The paper presents an efficient approach to design a Cassegrain optical system for spaceborne remote sensing. The optical system has a focal length of 1000mm, F number of 5.6, the range of spectral band 0.4~0.9μm, and field of view 3°, distortion smaller than 1%. The effect of central obscuration on the image quality in the optical reflective system design is analyzed. It provides proof for reasonable choose of obscuration ratio in optical system design. With the help of CODE V software, the final two designs are obtained by a simple and quick optimization step, the image quality of which reaches the diffraction limit. It is shown the second structure style is designed by making the surface of primary mirror in the Cassegrain system hyperbolic, adding two high order aspheric surfaces and removing two lenses from lens compensator, and therefore the second with the simpler structure, smaller size and lighter weight, comparing with the first structure style, can be used in spaceborne remote sensing. © 2012 SPIE.
Yuan G.-N.,Harbin Engineering University |
Zuo Z.-D.,Harbin Engineering University |
Zuo Z.-D.,Huazhong Institute of Electro Optics |
Qu G.-T.,Harbin Engineering University |
Ji H.,Harbin Engineering University
Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong University of Science and Technology (Natural Science Edition) | Year: 2013
In order to suppress the system chattering exist in the classical sliding variable structure control and simplify the computational process of second-order sliding variable structure controller, a reaching condition of second-order sliding variable structure control was proposed. When the control system was under the reaching condition, two results were got by applying the ordinary differential equations theory and Lyapunov stability theory: the one is the system phase trajectory can converge to the sliding mode in finite time; the other is the control system has excellent robustness. Finally, a system variable structure controller was designed with the reaching condition. Simulation results show that the reaching condition with excellent robustness can suppress the system chattering effectively.
Zhao K.,Huazhong Institute of Electro Optics |
Che C.-C.,Huazhong Institute of Electro Optics
Journal of Applied Optics | Year: 2013
Observing star in shortwave infrared (SWIR) spectrum has been considered as one of the important development directions of star sensor. According to the characteristic of wide waveband used in SWIR star sensor and the two feasible methods for correcting secondary spectrum in theory, an SWIR star sensor optical system with 900 nm~1 700 nm band, F number of 1.5 and the equivalent focal length (EFL) of 150 mm was designed based on the method of selecting the glass combination of the same or nearly relative dispersion coefficient and obviously different dispersion coefficient. Result shows that the secondary spectrum is corrected in broad band, the MTF in full field of view is more than 0.65 at 32 lp/mm. The system has excellent performance that can satisfy the requirement of observing star in near infrared band.