Southwest Jiaotong University Development of Basic Navigation Satellite Concept 1964-1967 SYSTEMATIC STUDY OF EVERY WILD IDEA IMAGINABLE CONVERGED ON“ PSEUDORANGING”IN1967 MAJOR STUDY CONTRACTS LET IN 1968TO TUNE THE CONCEPT Motto Adopted by the Joint Program Office on GPS Program The mission of this program is to 1. Drop 5 bombs in the same hole, and 2. Build a cheap set that navigates(<$10,000), and dont you forget it! 卫星定位技术与方法—一袁林果 2005-2-25
6 Development of Basic Navigation Satellite Concept 1964-1967 • SYSTEMATIC STUDY OF EVERY WILD IDEA IMAGINABLE • CONVERGED ON “PSEUDORANGING” IN 1967 • MAJOR STUDY CONTRACTS LET IN 1968 TO TUNE THE CONCEPT 卫星定位技术与方法——袁林果 2005-2-25 12 The mission of this Program is to: 1. Drop 5 bombs in the same hole, and 2. Build a cheap set that navigates (<$10,000), and don’t you forget it! Motto Adopted by the Joint Program Motto Adopted by the Joint Program Office on GPS Program
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(14
7 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
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(16
8 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