Convergence on Final System 1973-1974 SWITCHED CONCEPT TO 12-HOUR CIRCULAR ORBITS RETAINED DIRECT-SHIFT KEYED SPREAD SPECTRUM PN SEQUENCE DUAL FREQUENCY SIGNAL ON L-BAND · PICKED INITIAL DEPLOYMENT OF4+2· BLOCK I” SATELLITES 卫星定位技术与方法—袁林果 20052-25(15 HASE I DESIGN 1974-1980 BLOCK I SATELLITE CONTRACTS WITH ROCKWELL INTERNATIONAL lowed by 6 more All satellite performance projections achieved. 3dB more transmitted power then required Exceptional(Ix 10on-orbit Rubidium clock performance achieved DETAILS OF SIGNAL STRUCTURE NAV MESSAGE DEFINED C/A code designed with civil sector in mind Navigation message identical on both signa 電卫星定位技术与方法一袁林果 2005225(168 卫星定位技术与方法——袁林果 2005-2-25 15 Convergence on Final System 1973-1974 • SWITCHED CONCEPT TO 12-HOUR CIRCULAR ORBITS • 3 planes, 8 satellites each • i = 63° • RETAINED DIRECT-SHIFT KEYED SPREAD SPECTRUM PN SEQUENCE • DUAL FREQUENCY SIGNAL ON L-BAND • PICKED INITIAL DEPLOYMENT OF 4+2 ‘BLOCK I” SATELLITES 卫星定位技术与方法——袁林果 2005-2-25 16 • BLOCK I SATELLITE CONTRACTS WITH ROCKWELL INTERNATIONAL • 6 satellites followed by 6 more • All satellite performance projections achieved. 3dB more transmitted power then required • Exceptional (1x ) on-orbit Rubidium clock performance achieved. PHASE I DESIGN 1974-1980 10-13 • DETAILS OF SIGNAL STRUCTURE & NAV MESSAGE DEFINED • C/A code designed with civil sector in mind • “P-Code” designed by Magnavox • Navigation message identical on both signals