A Novel Spaceborne Antenna Repositioning Method for Reliable Communication in Inclined Satellites

Abstract

This study introduces a novel method for repositioning multi-steerable antennas on inclined geostationary earth orbit (GEO) satellites to enhance signal quality by mitigating signal degradation caused by coverage shifts due to satellite inclination. The innovation of this research lies in the real-time tracking of target ground stations (boresights) by spaceborne satellite antennas to maintain stable coverage footprints, marking a first in inclined geostationary satellite operations. Orbit simulations and analyses were conducted on the operational satellite Sat-A to evaluate the proposed onboard satellite antenna repositioning (OSAR) method. Various inclination angles (1°, 2°, 4°, and 6°) were considered, focusing on two coverage areas, BR1 and BR2. The method was validated through simulations by comparing Sat-A's zero-inclination baseline values with the repositioning results when pointing towards ground stations. The repositioned spaceborne antennas (S1 and S2) achieved remarkable pointing accuracy, with maximum errors of only 0.0165° in latitude and 0.0023° in longitude. Corresponding link performance metrics further confirmed the method's reliability, showing an equivalent isotropically radiated power (EIRP) deviation of 10⁻¹³ dB and an energy per bit to noise density ratio (E_b/N₀) variation of just 0.0795 dB. This performance is particularly critical for regions affected by beam shifts due to inclination. The simulation results demonstrate that the OSAR method is both accurate and cost-effective, making it suitable for various satellite services. By ensuring signal quality during inclined operations, the OSAR method offers a robust solution for satellite operators, enabling the delivery of reliable and high-quality services to customers.