Time filter

Source Type

Huludao, China

Tong G.,Element 95 | Cha Y.,Element 95
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology

The key of underwater terrain aided navigation is terrain matching, and the reliability of matches is one of the important issues. Based on the information contents of terrain navigation, four feature vectors, i.e. standard deviation of terrain height, signal to noise ratio, terrain entropy and similarity, are selected to determine the reliability of matches. Simulation results show that when the autonomous underwater vehicle(AUV) enters the terrain information-rich region(which has high reliability), the terrain aided navigation system is relatively high reliability, the position error is reduced from 3″ to less than 1.5″, providing a reliable source of location information for AUV navigation. Source

Cai Y.-B.,Element 95 | Li D.-B.,Element 95
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology

The CCD photoelectric deformation measurement system transmitting and receiving optics unit are respectively fixed on the united base. The system can detect the torsion angular of the united base through the obliquity change of interference stripe in the acquired image. It can also detect the pitch and yaw angular distortion through the transverse and lengthwise movement of interference fringe center position on the camera focal plane. To counter the stripe images, the center of each on line stripe can be obtained through enlarging each stripe and subdivide gray the value of pixel about the single-line images. All center line make up the axis skeleton of stripe. Thus new test methods about stripe's subdivision are formed. After that, the group by the stripes have been subdivided to carry out least square fitting and operation according to the preconditions about the same slope of all stripes and the space between is an approximate constant of interclass and among groups, the obliquity can obtained. The experiments indicate that the proposed method has preferable performance for the real-time and precision of the system. Error analysis and calculated shows that the system precision can reach 25″ in torsion angular measurement and 5″ in pitch and yaw distortion measurement. Source

Cai Y.-B.,Element 95 | Li D.-B.,Element 95
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology

To overcome the performance deficiency of conventional underwater positioning sensor in positioning, a 4DOF positioning approach using monocular vision based on target light-source was put forward. The principle of 4DOF positioning calculation was derived, and the methods of depth location, horizontal location and heading location were presented. The location light-source system with collinear permutation was designed to be used as target light. The static and dynamic tests verify that the principle of the proposed method is correct, and the target light-source positioning system based on monocularvision is reasonable and feasible, which can implement stable 4DOF-positioning within depth 4-0.5 m. The relative accuracy related to SBL and altimeter is within 10 cm after correction. Test results show that the proposed method have practical value for the AUV undertaking short-distance mission. © 2015, Editorial Department of Journal of Chinese Inertial Technology. All right reserved. Source

Li D.-B.,Element 95 | Liu S.-Z.,Element 95
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology

The orienting and locating technology by multi-satellites synchronous detection is put forward to realize the real-time measurement of INS attitude error. The primary measure scheme is designed, in which the basic principles and mathematics model of the location and orientation technology for the wide FOV is emphatically introduced, and theory analysis is made on the key techniques, such as star static detection, star dynamic detection and star pattern recognition. It provides a feasible method for improving the real-time measure precision of the INS attitude. The error analysis and calculation results show that the location accuracy in static condition is less than 100 m, and this meets the measure requirements. Source

Zhang W.,Element 95 | Cai Y.-B.,Element 95 | Wei X.-T.,Element 95
Applied Mechanics and Materials

A highly robust active disturbance rejection controller (ADRC) is developed in this paper. The proposed ADRC consists of a tracking differentiator (TD) in the feed forward path, an extended state observer (ESO), and a nonlinear state error feedback control law (NLSEF) in the feedback path. The control theory, the structure of ADRC and the controller design are presented. LabVIEW is used for modeling, simulation and analysis of the dynamic system. Simulation results show that the proposed ADRC has excellent control performance, especially outstanding adaptability and robustness external disturbances and model uncertainties. © (2013) Trans Tech Publications, Switzerland. Source

Discover hidden collaborations