Miniaturizing the spherical sundial: A hemispherical sensor for orientation and positioning with respect to point sources of light

We propose a novel solar sensor geometry utilizing a hemispherical arrangement of pixels to determine the vector to the dominant light source in its environment. We show two methods for calculating this vector: one based on transforming the problem from an optical one into a geometric one, and another using a least squares approach to minimize the error function for the sensor. These methods do not depend on the physical details of any particular sensor design. Both methods rely upon certain assumptions, but methods for extracting an accurate sun vector are discussed which do not rely upon such an idealized environment. Using the estimate of the sun vector, it is possible to determine the location of the sensor on the Earth. Applications include position measurement and navigation for UAVs, UGVs, and other mobile platforms.