Change-over strategies for highly elliptical orbits

The communication performance of satellite systems using high inclined elliptical orbits has to be changed-over from one satellite to the other. For typical orbit systems using 24 h Tundra orbits or 12 h Molniya orbits this must be performed two or three times a day, respectively. The paper summarizes different strategies identified for the Archimedes voice communication land mobile satellite system. The aim of the study was to find satellite change-over (SCO) strategies with either `not noticeable´ or `acceptable´ communication signal interruptions. There are two basic strategies, namely simultaneous handover of all voice channels between satellites at once, or gradual handover during a certain period where both satellites are operating simultaneously