Major Issues Identified in 1968 Studies CHOICE OF CARRIER FREQUENCY ·L-Band C-Band should be studied DESIGN OF SIGNAL STRUCTURE Military and civilian use included ORBIT/CONSTELLATION SELECTION 卫星定位技术与方法—袁林果 20052-25(1 Managed Concept Debates 1969-1972 EXPANDED TRANSIT Insisted on worldwide overage 153 satellites in 400 mile polar orbits Transit carrier frequency XPANDED TIMATION Initially only a Time Transfer System Insisted on worldwide coverage Expanded concept to intermediate altitude circular orbit constellation of 30 to 40 satellites 卫星定位技术与方法—一袁林果 20052-25(147 卫星定位技术与方法——袁林果 2005-2-25 13 Major Issues Identified in 1968 Studies • CHOICE OF CARRIER FREQUENCY • L-Band • C-Band should be studied • DESIGN OF SIGNAL STRUCTURE • Military and civilian use included • ORBIT/CONSTELLATION SELECTION 卫星定位技术与方法——袁林果 2005-2-25 14 • EXPANDED TRANSIT • Insisted on worldwide overage • 153 satellites in 400 mile polar orbits • Transit carrier frequency • EXPANDED TIMATION • Initially only a Time Transfer System • Insisted on worldwide coverage • Expanded concept to intermediate altitude circular orbit constellation of 30 to 40 satellites Managed Concept Debates 1969-1972