Abstract
For the laser tracking and positioning system of a moving target using a four-quadrant detector, the accuracy of laser spot position detection has a serious impact on the tracking performance of the system. For moving target tracking, the traditional spot position detection method of a four-quadrant detector cannot give better consideration to both detection accuracy and operation speed. In view of this, an improved method based on piecewise low-order polynomial least squares fitting and a Kalman filter is proposed. Firstly, the tracking and positioning mathematical model of the system is created, and the experimental device is established. Then, the shortcomings of traditional methods are analyzed, and the improved method and the real-time tracking and positioning algorithm of the system are studied. Finally, through the experiment, the system operation effects are compared and analyzed before and after the improvement. The experimental results of system dynamic tracking show that, the least squares fitting of the experimental data using a 5-segment and quadratic polynomial can achieve better results. By using the improved method, the maximum tracking distance of a moving object is increased from 12 m to more than 30 m. At a distance of 7.5 m, the maximum tracking speed can reach 2.11 m/s, and the root mean square error (RMSE) of the position is less than 4.59 mm. At 15.5 m, the maximum tracking speed is 2.04 m/s and the RMSE is less than 5.42 mm. Additionally, at 23.5 m, it is 1.13 m/s and 5.71 mm.
Highlights
Laser tracking technology has a wide range of applications in the fields of laser guidance [1], space optical communication [2,3], optical tweezers [4], and large size precision measurement [5,6,7].Compared with other non-contact positioning methods, such as wireless sensor networks [8] and inertial navigation positioning [9], laser tracking and positioning has the advantages of high accuracy and strong environmental adaptability
The relationship between the target moving distance and the rotation angles of the spot position detection is (0,0) and the indicator laser is re-projected into the center of the target prism
Because the experimental data {xδ : δx } has implied various spot position errors caused by the spot shape, strip dark area, and various inherent errors, the analytical equation between xδ and δx can be established by fitting the experimental data {xδ : δx }, and the fitting curve can be curve can be used as a high-precision spot position detection model
Summary
Laser tracking technology has a wide range of applications in the fields of laser guidance [1], space optical communication [2,3], optical tweezers [4], and large size precision measurement [5,6,7]. Xiao [16,17] and other scholars have made in-depth studies on the theory and method of multi-sensor information fusion These methods can be a feasible way to improve the spot position accuracy of a laser tracking system. In order to establish the spot position detection model with a simple algorithm and fast processing speed, the piecewise low-order polynomial fitting algorithm is adopted to fit the experimental data, and the fitting curve between the output voltages of the 4-QD and the spot position satisfying the tracking accuracy of the system is obtained, which can be used as the improved model to compensate for the inherent errors.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
