Adaptive control and calibration of heliostats

A large field of heliostats (steerable mirrors) are oriented to reflect light to a central receiver in solar/electric energy conversion. To achieve high pointing accuracy, each heliostat is calibrated for errors in the heliostat drives and installation. The sun is used as a precision position reference and the heliostat pointing errors are estimated at periodic intervals. A least-squares algorithm is used to estimate the model parameters. Simulation results are given for a typical heliostat configuration with realistic errors. Effectiveness of the error model is analyzed for different mirror pedestal tilts, azimuth and elevation biases and drive wheel radius tolerances.