Real-time atmospheric refraction error correction method for optoelectronic equipment
With the rapid development of satellite internet technology,the world's major space powers and commercial organizations are planning to build large-scale low-orbit constellations,including OneWeb and StarLink.It is predicted the number of satellites in orbit and the frequency of rocket launches will increase sharply,setting much higher requirements for rocket launch measurement tasks.The optoelectronic equipment,crucial in space target information measurement at the space launch site,directly determines the success of a rocket launch mission.Radio waves are susceptible to atmospheric refraction in the process of atmospheric propagation.Atmospheric refraction errors occur in the process of external measurement of data while optoelectronic equipment is employed.Currently,the atmospheric refraction correction method at the space launch site is generally divided into two categories:the ex-post precise correction model and the real-time empirical correction model.The ex-post precise correction model mainly refers to the hierarchical integration method and achieves high accuracy.However,it usually fails to meet the requirements of real-time tasks due to large amounts of iteration integration.The real-time empirical correction model is fast,but it causes certain deviation in the correction results due to the simplified calculation with empirical parameters.To improve the real-time measurement accuracy of optoelectronic equipment during rocket launches,we proposes a new atmospheric refraction correction model based on Gaussian integral.It obtains the tropospheric refractive index at different heights through the meteorological profile data collected by the radio wave refraction corrector.Then,the fitted calculation for initial coefficients of the target relative to the height of the station is conducted.Finally,the apparent distance of the rocket,the true height of the rocket,and the atmospheric refraction correction results of the range,elevation and velocity are calculated through just one integral.To further improve the computational efficiency,especially the integration speed when the rocket flight altitude is high,the Gaussian integration method is adopted for easier computer operation.The Gaussian integral constant is also used in the calculation process to improve the integration efficiency.Our method fully employs the meteorological profile data,adopts the Gaussian integral to improve the calculation efficiency.It obtains the atmospheric refraction correction results with just one numerical integration.A comparative analysis indicates our method completes a correction in less than 10 milliseconds,fully meeting the requirements of real-time tasks.Moreover,the correction accuracy is markedly higher than that of the existing real-time empirical correction models,and is comparable to that of the post-iterative integration model.In short,our method boasts the rapidity of the real-time empirical correction model and the high accuracy of the post-iterative integration model.
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