Author_Institution :
Jet Propulsion Lab., California Inst. of Technol., Pasadena, CA, USA
Abstract :
A solar compass chip (SCC) is a photosensitive chip with MEMS-based optics (pinhole aperture array) integrated on the chip itself. The MEMS-based optics enables the chip to image the sun. Image processing of the sun image is performed externally to the SCC (typically a processor connected to the SCC). The sun is observed for a period of time, say half an hour, and the angles to the sun are calculated. During that period of time, the sun will slew across the sky due to the sidereal rate. A circle on the surface of a sphere can be fitted to the arc on the sky that the sun traverses. The center of this circle is the rotation axis of the Earth. Besides performing the function of a compass, the SCC can be combined with a clock to establish a three-axis inertial-based coordinate system, or if the vertical is known, to determine the geographic position. A number of commercial applications in the automotive, agricultural, and maritime areas are identified.
Keywords :
attitude measurement; avionics; cameras; compasses; image sensors; micro-optics; micromechanical devices; position measurement; Earth rotation axis; MEMS-based optics; angle calculations; attitude determination; compass heading; geographic position determination; image processing; inertial-based coordinate system; photosensitive chip; pin-hole camera; pinhole aperture array; solar compass chip; sun imaging; sun sensor; three-axis coordinate system; Apertures; Cameras; Image processing; Optical arrays; Optical sensors; Propulsion; Silicon; Space technology; Space vehicles; Sun; 65; Attitude determination; compass heading; pinhole camera; position determination; sun sensor;
