CODELESS GPS ATTITUDE DETERMINATION SYSTEM (CGADS)

A PROGRAM LEADING TO THE DEFINITION OF A SPACEBORNE ATTITUDEDETERMINATION SYSTEM BASED UPON GPS SIGNALS IS PROPOSED. THE SPECIFIC INNOVATION INVOLVES PROCESSING GPS SIGNALS WITHOUT KNOWLEDGE OF THE DIGITAL CODES REQUIRED FOR CONVENTIONAL GPS RECEIVERS, MAKING THE SYSTEM IMMUNE TO PERFORMANCE DEGRADATION RESULTING FROM THE DOD POLICY OF SELECTIVE AVAILABILITY/ANTI-SPOOFING. PRECISION DETERMINATION OF ATTITUDE (0.05DEG) AND RATE (0.05 DEG/SEC) CAN BE ACHIEVED AT UP TO 10 HZ. THIS PROJECT ADDRESSES THE NEED FOR A LOW-COST, LOW-POWER, AND LOW-MASS ATTITUDE DETERMINATION SYSTEM FOR USE ABOARD SMALL SATELLITE MISSIONS. THE PROPOSED SYSTEMS ENGINEERING CONSISTS OF FIVETASKS: (1) REQUIREMENTS DEFINITION FOR THE ON-BOARD RADIO SYSTEM ELECTRONIC DESIGN, (2) REQUIREMENTS FOR THE SATELLITEHARDWARE SUITE, (3) ATTITUDE DETERMINATION FLIGHT SOFTWARE SPECIFICATIONS, (4) GROUND SUPPORT SEGMENT DEFINITION, (5) PLANNING FOR A GROUND-BASED PROOF-OF-CONCEPT DEMONSTRATOR TOBE EXECUTED UNDER PHASE II. THE EXPECTED BENEFITS TO NASA ARE NUMEROUS WITH THE CURRENT TREND TOWARD DEVELOPMENT OF SMALL, LOW-COST, MULTI-MISSION SATELLITES. AS GPS SYSTEMS BECOME A REALITY, THEY CAN BE EXPECTED TO OBSOLETE TRADITIONAL ATTITUDE DETERMINATION SYSTEMS AND HARDWARE. ASAN ADDITIONAL BENEFIT, THIS SYSTEM IS EASILY ADAPTABLE FOR PRECISION ORBIT DETERMINATION.