Micro Sun Sensor for Spacecraft

NASA's Jet Propulsion Laboratory, Pasadena, California

A report describes the development of a compact micro Sun sensor for use as a part of the attitude determination subsystem aboard future miniature spacecraft and planetary robotic vehicles.

The prototype unit has a mass of only 9 g, a volume of only 4.2 cm³, a power consumption of only 30 mW, and a 120∞ field of view. The unit has demonstrated an accuracy of 1 arc-minute. The unit consists of a multiple-pinhole camera: A micromachined mask containing a rectangular array of microscopic pinholes, machined utilizing the microectromechanical systems (MEMS), is mounted in front of an active-pixel sensor (APS) image detector. The APS consists of a 512 x 512-pixel array, on-chip 10-bit analog to digital converter (ADC), on-chip bias generation, and on-chip timing control for self-sequencing and easy programmability. The digitized output of the APS is processed to compute the centroids of the pinhole Sun images on the APS. The Sun angle, relative to a coordinate system fixed to the sensor unit, is then computed from the positions of the centroids.

This work was done by Sohrab Mobasser, Carl Liebe, Youngsam Bae, Jeffrey Schroeder, and Chris Wrigley of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Electronics /Computers category.

NPO-30867