DUAL MODE POSITION REGISTRATION METHOD

摘要

PROBLEM TO BE SOLVED: To prevent mode changeover from being flapped at an end of a service area. SOLUTION: A mobile station 30 selecting a satellite system mode enters a service area 2 of a ground system and outputs a position registration request and a ground system base station 41 uses a circuit for time alignment to measure a time difference between the request signal and a reference signal. When the time difference is large, that is, the mobile station 30 is resident in a detached position 23 or an end of the area 2 and there might be possibility of occurrence of flapping for mode selection, then a position registration request reject is reported to the mobile station, and when the time difference is less than the prescribed time difference, the position registration is permitted.