Question-Based Gap Analysis of Heliostat Optical Metrology Methods

Abstract

As part of the DOE Heliostat Consortium Roadmap study, we investigated optical metrology systems for heliostats, seeking areas where further research was needed. We began by considering optical metrology questions of interest across the heliostat development cycle and identified information types common across this spectrum. In addition to raising questions of interest, each development cycle phase implied specific operation requirements. Combining these yielded 13 core problem statements, four of which do not appear to have a readily available solution: (a) in-situ measurement of high-resolution maps of mirror surface normals, for all heliostat tilt angles and heliostats far from the tower; (b) accelerated heliostat calibration; (c) high-speed in situ measurement of heliostat surface normal maps and pointing directions; (d) ground truth methods for verifying the accuracy of surface normal map measurements. This analysis may provide input to the selection of future research goals.