A High-Reliable and High-Precision Algorithm of Angle Measurement for UAV Airborne Photoelectrical Detection System

Abstract

In order to achieve high-reliable and high-precision target measurement for UAV photoelectric detection system without increasing any costs, an algorithm of angle measurement is proposed. Firstly, by analyzing the character of grating grid image’s edge, a fast method using three gradient points to establish a parabolic function is applied for automatic grating image sub-pixel edge detection. Coarse code decoding is improved by OTSU’s method to reduce bit error rate (BER) as well as manufacturing difficulty, and a high-precision subdivision method based on observed image of grating lines is introduced to calculate subdivision angle. Secondly, simulation of BER and precision analysis show that proposed algorithm is robust in both processes of coarse code decoding and subdivision. Finally, experiment results show that BER is no more than 0.02%, the standard deviation of proposed algorithm is 1.8″ and the standard deviation of error is only 7.1″ with one reading head, indicating that proposed algorithm is robust, reliable and precise.