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Shi J.,Beijing Aerospace Times Laser Inertial Technology Co.
2011 IEEE International Conference on Information and Automation, ICIA 2011 | Year: 2011

According to the accumulation characteristic of SINS positioning error caused by inertial sensor error, this paper brought the rotation monitor technique to improve the SINS accuracy. Dual-axis consequential rotation scheme is designed by deeply analyze toward the existing single-axis and two-axis scheme. This scheme is selected as the final scheme by analyzing modulation results of constant gyro drift, the gyro scale error and the deviation of the gyro installation error. Computer simulation shows that this scheme has better modulation than single-axis and two-axis continuous scheme and can improve position accuracy of SINS effectively. © 2011 IEEE.

Wang L.,Beihang University | Zhang C.,Beihang University | Gao S.,Beihang University | Wang T.,Beijing Aerospace Times Laser Inertial Technology Co. | And 2 more authors.
Optik | Year: 2016

The dynamic Allan variance (DAVAR) [1] is a useful tool to track non-stationaries in the behavior of gyroscopes. It allows us to diagnose whether the stability of gyroscopes is changing with time. Unfortunately, with the length of the analyzed time series increasing, the computational time of the DAVAR grows very quickly. Consequently, it costs huge time to deal with the data. In this article, a Fast algorithm of the DAVAR for gyroscopes is developed. In order to verify its validity, three sets of simulation data are characterized by the Fast algorithm and the classical one. The Fast DAVAR could reduce the computational time dramatically when the long time series is analyzed. Furthermore, a vibration experiment with fiber optic gyroscopes has been implemented to validate the good performance of the Fast algorithm. Compared with the classical one, the Fast algorithm of the DAVAR shortens the computation time 6 times. In conclusion, the Fast algorithm of the DAVAR guarantees a dramatic reduction of the computational time and outperforms the classical DAVAR. © 2015 Elsevier GmbH. All rights reserved.

Wang L.,Beihang University | Zhang C.,Beihang University | Lin T.,Beihang University | Li X.,Beihang University | Wang T.,Beijing Aerospace Times Laser Inertial Technology Company Ltd
Measurement: Journal of the International Measurement Confederation | Year: 2015

The environment influences Fiber Optic Gyroscopes (FOG) directly. Thus, FOGs in Measurement While Drilling (MWD) system exhibit a non-stationary behavior over time due to strong vibration, high-speed rotation and temperature increasing. Therefore, it is important to introduce a representation that can take the time-varying nature of FOGs' stability into account. The Allan variance is a common and standard method to analyze FOGs, but it cannot be used to analyze the dynamic characteristics. In this effort, a method based on the dynamic Allan variance (DAVAR) was developed. Firstly, the validity of DAVAR was verified by simulated data. Secondly, the FOG working in the harsh environment was characterized by the DAVAR. According to the results, an improved experiment was implemented to verify the practical application of the DAVAR. In addition, a 2-D diagram is used for the first time to illustrate the noise characteristics of FOGs. A 2-D analysis diagram can not only separate and distinguish the stochastic noise term, but also track and reveal the changes in the behavior of FOGs in a clear and intuitive manner. In conclusion, with the new method developed by this paper, the performance of FOGs can be evaluated more comprehensively and effectively. © 2015 Elsevier Ltd. All rights reserved.

PubMed | Beihang University and Beijing Aerospace Times Laser Inertial Technology Company
Type: Journal Article | Journal: Sensors (Basel, Switzerland) | Year: 2016

The stability of a fiber optic gyroscope (FOG) in measurement while drilling (MWD) could vary with time because of changing temperature, high vibration, and sudden power failure. The dynamic Allan variance (DAVAR) is a sliding version of the Allan variance. It is a practical tool that could represent the non-stationary behavior of the gyroscope signal. Since the normal DAVAR takes too long to deal with long time series, a fast DAVAR algorithm has been developed to accelerate the computation speed. However, both the normal DAVAR algorithm and the fast algorithm become invalid for discontinuous time series. What is worse, the FOG-based MWD underground often keeps working for several days; the gyro data collected aboveground is not only very time-consuming, but also sometimes discontinuous in the timeline. In this article, on the basis of the fast algorithm for DAVAR, we make a further advance in the fast algorithm (improved fast DAVAR) to extend the fast DAVAR to discontinuous time series. The improved fast DAVAR and the normal DAVAR are used to responsively characterize two sets of simulation data. The simulation results show that when the length of the time series is short, the improved fast DAVAR saves 78.93% of calculation time. When the length of the time series is long ( 6 10 5 samples), the improved fast DAVAR reduces calculation time by 97.09%. Another set of simulation data with missing data is characterized by the improved fast DAVAR. Its simulation results prove that the improved fast DAVAR could successfully deal with discontinuous data. In the end, a vibration experiment with FOGs-based MWD has been implemented to validate the good performance of the improved fast DAVAR. The results of the experience testify that the improved fast DAVAR not only shortens computation time, but could also analyze discontinuous time series.

Liu Y.,Beijing Aerospace Times Laser Inertial Technology Co. | Lang Z.,61081 PLA Troops | Tang W.,Harbin Institute of Technology
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2012

A material surface roughness measurement system based on light-section principle and consisted of CCD camera and conventional light-section microscope as well as by using of VC development tool and image process technique was developed. Due to the characteristic that the image of the material surface roughness under light-section microscope had obvious directivity, the images were preprocessed by using of the spin filtering method and the roughness measurement results were compared with the ones based on the conventional filtering methods. The influences of the size of filter window and the filtering method on the tangent direction on measurement results were discussed at the same time. All parameters of the new national standard can be measured by using of this measurement system, and the on-line measurement can be realized. The calibration method of the system was introduced and the main error factors of influencing measurement precision were analyzed. The arithmetical mean deviation Ra which value was 3.2 μm was measured, and the result is 2.93 μm and the relative error is -8.5% which is less than the indicating value allowable error of the system.

Shi X.-L.,Zhejiang University | Ma L.-H.,Zhejiang University | Ma L.-H.,Zhejiang University of Science and Technology | Li Z.-Y.,Beijing Aerospace Times Laser Inertial Technology Company
WIT Transactions on Information and Communication Technologies | Year: 2014

Navigation and positioning under high dynamic environments is one of the hottest scientific research fields currently. As the GPS signals under high dynamic environments are difficult to obtain, this paper presents a GPS signal simulation algorithm. Firstly, a mathematical signal model is analyzed. And then the parameters are calculated, and the algorithm for GPS satellite signal simulation is given. The GPS intermediate frequency signal simulator is developed based on the algorithm. Finally, experiments are implemented to verify the reliability and validity of simulated GPS signal. © 2014 WIT Press.

Sun P.,Inner Mongolia University of Technology | Xing Z.,Inner Mongolia University of Technology | Wang H.,Beijing Aerospace Times Laser Inertial Technology Co. | Zhang Y.,Inner Mongolia University of Technology | Gao J.,Inner Mongolia University of Technology
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2015

From the perspectives of engineering, taking the blade of certain 1.5 MW wind turbine as the research object and the most optimal structure performance as target, using the combining method of theoretical analysis, finite element analysis and structural optimization, applying hierarchical optimization strategy, the optimal mathematic model, objective function and constraint condition were established. The optimal lamination scheme of blade was obtained by optimizing lay-up angle, lay-up thickness and lay-up sequence, respectively. The structure analysis results indicate that the maximum principal stress and strain of the optimized blade are reduced obviously, respectively. The correctness and effectiveness of the optimization scheme and method are verified. ©, 2015, Science Press. All right reserved.

Cheng J.,Harbin Engineering University | Shi J.,Harbin Engineering University | Shi J.,Beijing Aerospace Times Laser Inertial Technology Company | Rong W.,Harbin Engineering University | Yan L.,Beijing Aerospace Times Laser Inertial Technology Company
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2011

The earth cycle oscillation component of latitude and heading error can decrease the accuracy of inertial navigation system. Based on the actual experiment navigation system, this paper covered a three-order damping network and designed an azimuth damping method with a multi-damping coefficient by means of step-by-step attempts. The network can damp the earth cycle oscillation and adapt to various maneuver motions of the carrier by adopting an automatic compensation technique which can decrease the overshooting error during the state switching. The result of the velocity error simulation shows that the multi-azimuth damping project can damp the earth cycle oscillation and the automatic compensation technique can eliminate the switch overshooting effectively.

Yuan G.-N.,Harbin Engineering University | Liang H.-B.,Harbin Engineering University | He K.-P.,Harbin Engineering University | Wang W.,Beijing Aerospace Times Laser Inertial Technology Company
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2011

To solve the problem that GPS can not supply continuous navigation information due to GPS block in complex terrains, an integrated navigator for vehicle application is built which includes GPS, micro-mechanical inertial navigation system, and electronic compass. The strategy of integration is presented whose judging condition is whether GPS information is valid or not. If the GPS information is valid, the integration algorithm takes the position error as its measurement vector, and if the GPS information is invalid, it applies velocity constraints in the aided navigation algorithm. The test results show that the algorithm can effectively restrain the position errors during GPS outages, which ensures the accuracy of navigation and continuity of navigation information.

Miao Z.,Beijing Aerospace Times Laser Inertial Technology Company | Fan M.,Beijing Aerospace Times Laser Inertial Technology Company | Wang Y.,Beijing Aerospace Times Laser Inertial Technology Company | Yin Y.,Beijing Aerospace Times Laser Inertial Technology Company | Wang D.,Beijing Aerospace Times Laser Inertial Technology Company
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

A high voltage power supply used in laser gyro is proposed in this paper. The power supply which uses a single DC 15v input and fly-back topology is adopted in the main circuit. The output of the power supply achieve high to 3.3kv voltage in order to light the RLG. The PFM control method is adopted to realize the rapid switching between the high voltage state and the maintain state. The resonant chip L6565 is used to achieve the zero voltage switching(ZVS), so the consumption is reduced and the power efficiency is improved more than 80%. A special circuit is presented in the control portion to ensure symmetry of the two RLG's arms current. The measured current accuracy is higher than 5‰ and the current symmetry of the two RLG's arms up to 99.2%. © 2016 SPIE.

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