Patent ID: 7207327

Claim:
A closed loop error detection system for determining a positioning error of a heliostat relative to a receiver of a solar energy plant, the system comprising: a positional error detection instrument positioned adjacent a face of the heliostat and between the heliostat face and the receiver, the positional error correction instrument comprising: an image detector configured to: receive a reflected image of the sun at a random location on the image detector that is based on a reflection angle of the image of the sun as the image of the sun is reflected from the heliostat face; and receive an image of the receiver at a fixed location on the image detector, the receiver image reflected from the receiver directly into the positional error detection instrument; and a comparator configured to: determine a distance between the randomly located image of the sun and the fixed location of the receiver image, the distance representing a pointing error of the heliostat relative to the receiver, and generate a pointing correction signal based on the pointing error; a controller configured to receive the pointing correction signal; and a positioner configured to be controlled by the controller to adjust the position of the heliostat to eliminate the pointing error.