Heliostat

Task

A heliostat is a mirror that reflects the sunlight always on the same spot regardless of the sun's position. Whole fields of such mirrors are used for solar thermal power plants. The sunlight heats a medium that is used to generate electrical energy. Modern heliostats such as the Stellio heliostat shown here have a diameter of about 10m. A profound understanding of the behavior of the mirrors under wind loads is needed in order to optimize performance. As part of a research project at DLR, one of the major German research institutions, in Jülich, Germany, Linearis3D has developed a photogrammetric video system that is capable of detecting dynamic deformations of heliostats in all weather and lighting conditions.

Procedure

To solve the measuring task, Linearis3D created a dynamic photogrammetric measuring system with the following features.

• 4 cameras with 5 megapixel resolution
• Measuring frequencies up to 60 Hz
• Data volume up to 1.2 GB / s
• Workstation with 128GB RAM
• over 1000 retroreflective measurement points
• IP 67 protected cameras and lighting
• Dynamic orientation of the cameras
• Multi-Camera Calibration
• Comprehensive analysis and filtering functions in the software
• Expandable with additional cameras

Result

The video photogrammetry system makes precise 3D deformation measurments of a very high number of measuring points possible while requiring relatively little time and cost. As a result the system contributes significantly to the success of the research project.

We would like to thank DLR for the excellent cooperation.