A FULL SKY, HIGH RESOLUTION EARTH, SUN, AND MOON ATTITUDE SENSOR

AN ATTITUDE SENSOR FOR SPINNING OR DUAL SPIN SPACECRAFT IS PROPOSED WHICH PROVIDES FULL SKY (4 PI STERADIAN) COVERAGE PROVIDES 5 INDEPENDENT ATTITUDE MEASUREMENTS IN ADDITION TO ACCURATELY MEASURING THE EARTH'S DIAMETER (WHICH COULD BE OF SUBSTANTIAL VALUE FOR ORBIT DETERMINATION WHEN NEAR THE EARTH.) WE ANTICIPATE AN ATTITUDE ACCRUACY SUBSTANTIALLBETTER THAN 0.1 DEGREES FOR NEARLY ALL SATELLITE ORIENTATIONAND POSITIONS BETWEEN 100 N. MI. AND 250 EATH RADII. CONCEPTUALLY AND MECHANICALLY, SKY MAPPER IS A S STRAIGHTFORWARD EXTENSION OF AN EXISTING, ECONOMICAL FLIGHT PROVEN DESIGN. THE MULTIPLE, HIGH ACCURACY MEASUREMENTS GREATLY REDUCE THE PRINCIPLE ATTITUDE ERROR SOURCES. THEREFORE, SKY MAPPER WILL PROVIDE A MAJOR IMPROVEMENT IN ATTITUDE ACCURACY AT LITTLE OR NO INCREASE IN COST OR COMPLEXITY. IN ADDITION, THE SYSTEM HAS VERY SIMPLE ATTITUDE ALGORITHMS, THUS REDUCING THE COMPLEXITY AND COST OF GROUND SOFTWARE. PHASE II WOULD BE USED FOR DETAILED HARDWARE DEFINITION AND TO DEVELOP ENGINEERING MODEL FLIGHT HARDWARE AND PROTOTYPE ATTITUDE DETERMINATION SOFTWARE.