Research On Error Analysis And Accuracy Improvement Of Velocity Measurement Of Photoelectric Theodolite

Velocity of the measured target is the main basis for pointing technology, target acquisition and tracking during the time the photoelectric theodolite is tracking and measuring the target. Target’s velocity is fed back to the servo control system or the launching system weapon platform, in order to be the reference of continuous target acquisition or attacking parameter determination. As the essential instrument, the photoelectric theodolite can only get the azimuth angle and the pitch angle of the targets, not the velocity at the tracking moment, when the photoelectric theodolite tracks the targets in the range.Many things should be done to determine the velocity of targets at any time point. This paper is based on the experimental data which are from the measuring data of photoelectric theodolite. In order to measure the velocity and other moving parameters of tracking targets as well as improve the measuring accuracy, this paper has conducted the study of the method of measuring velocity and the accuracy of measuring velocity in three aspects, that are basic theory analysis, numerical simulation and error distribution. The measuring accuracy of every moving parameter has been improved.First of all, propose a new method of measuring the object position information by single-theodolite and intersection by two-theodolites. The source of position error is analyzed and the positioning accuracy of our proposed method and intersection measurement by two-theodolites is compared. The new method avoids problems of easily losing targets of single-theodolite, oversized data of intersection by two-theodolites and bad real-time performance. The practicability of measuring method of single-theodolite and intersection by two-theodolites and the superiority of the precision of processing data are verified.Secondly, research the cubic spline interpolation to fit the motion track of targets. The fitting error is trajectory is reduced as a result of second order smoothness and good convergence of the cubic spline interpolation function. The fitting function of motion track, the function of velocity curves and the function of acceleration curves are given. The value and measuring accuracy of polynomial moving parameters are calculated so that the accuracy of measuring speed is improved.Finally, the factor of influence of measuring error on the accuracy of measuring velocity is analyzed from the point of error distribution. The measured values are given to reach the corresponding measuring accuracy under influence principle. And the possibility of realization is analyzed under principle of equal probability.In conclusion, this paper has a theoretical and experimental research on measuring the targets velocity and improving the velocity measuring accuracy of photoelectric theodolites. The experimental data show that the proposed method has the advantages of simple calculation method, good real-time, high measuring accuracy and so on, which has important reference sense for improving the accuracy of photoelectricity track and measurement.