Satellite Scanning Pattern for Optical Acquisition Considering Elliptical Shaped Field of Uncertainty

Abstract

This article proposes a scan method to reduce the acquisition time of intersatellite links based on the satellite position error distribution. The errors are modeled as an anisotropic multivariate Gaussian distribution, and the field of uncertainty (FOU) is defined as the five-sigma region of this distribution. Due to the significant errors typically found in the along-track direction, the FOU often takes an elliptical shape. We propose a scanning pattern to scan the elliptical FOU efficiently. Our approach was validated through Monte-Carlo simulations and analyses using GPS data from NEXTSat-2. The results indicate that the proposed scan method is more effective than the traditional method when the FOU is more elliptical. In the case of NEXTSat-2, the efficiency of the proposed method was confirmed, with the ratio of the semiminor to the semimajor axis was less than 0.2 in 70% of cases.