Area of Interest Selection Circuit for Image Sensor and/or Position Sensing Detector
Many proposed missions depend on the use of 'micro-satellite' constellations to make simultaneous measurements at different orbital locations. Numerous new technologies are required to make the micro-satellite concept viable from a mass and power standpoint. The apparent position of the sun is an important spacecraft attitude measurement that is used by virtually all attitude determination and control subsystems. This measurement is commonly made with a sensor called a digital solar attitude detector (DSAD). Micro-DSAD incorporating the entire sensor and its interface on a single chip would enable one to create a sensor small enough to be of great utility in micro-satellites for spacecraft formation flying, as well as applicability in nearly all NASA spacecraft missions.
APL is developing such a Micro-DSAD integrated circuit for use in micro-satellites. This detector promises to extend the accuracy of DSAD measurements to better than 0.01 arcsec. Such high accuracy measurements make the Micro-DSAD competitive with star cameras in many important commercial space applications. APL's Micro-DSAD uses a novel active-pixel sensor design to provide the functionality of both a sensitive Sun Sensor and a medium resolution image in a tiny 120 gram, 80 mW package. Data is read out via a standard serial interface; no additional circuitry is required. Today's equivalent sensor plus electronics weights 1.9 kg and draws 1.75 W. In addition, APL's Micro-DSAD can double as a housekeeping imager for use in monitoring solar panel, boom, antenna, and optical deployment. It is believed this imaging capability will broaden its range of applications, especially in microsats.
Patent Status: U.S. patent(s) 6930298 issued.
Mr. E. Chalfin
Phone: (443) 778-7473