Abstract: The figure‐8 satellite (quasi‐zenithal satellite) system is a satellite constellation consisting of three or more satellites placed in inclined geo‐synchronous circular orbits with an identical inclination of around 45 degrees. At any time, at least one of the three satellites is moving near the zenith view from Japan. The sub‐satellite point traces a so‐called ‘figure of eight’ locus on the ground, elongating in the north‐south direction with an arbitrary point on the equator in the center. The figure‐8 satellite system has several potential applications including mobile satellite communications at a high‐elevation angle, dual use of the same frequency between geostationary satellites and figure‐8 satellites in fixed‐satellite services, satellite‐based positioning, and observation of the polar region. This paper describes applications of the figure‐8 satellite system. In particular, the applicability of the satellite system to mobile satellite communications is shown by the experimental results of tests using the COMETS satellite.
Keywords: Figure‐8 satellite, mobile satellite communication, frequency sharing, positioning, polar region observation