Real-time profile measurement method for a large-scale satellite antenna

Area of Science:

• Aerospace Engineering
• Optical Metrology
• Signal Processing

Background:

• Satellite-based synthetic aperture radar (SAR) requires large antenna arrays (100m scale) for improved detection.
• Structural deformation in large antennas causes phase errors, significantly reducing antenna gain.
• Accurate, real-time profile measurements are essential for active phase compensation to maintain antenna gain.

Purpose of the Study:

• To develop a robust 3D displacement measurement method for large antenna plates under severe in-orbit conditions.
• To address challenges including limited installation space, large measurement areas, long distances, and environmental instability.
• To enable high-precision measurements for active phase compensation and improved SAR performance.

Main Methods:

• A hybrid approach combining laser distance measuring for depth information and digital image correlation (DIC) for in-plane displacement retrieval.
• Utilized a Scheimpflug camera to achieve clear imaging across the entire field of view, overcoming depth-of-field limitations.
• Implemented a vibration compensation scheme to mitigate measurement errors caused by camera support rod vibrations (within 0.01°).

Main Results:

• The proposed method effectively eliminated measurement errors caused by camera vibration (50mm displacement).
• Achieved a displacement measurement error within 1mm over a 60m measurement range in laboratory settings.
• Demonstrated suitability for the demanding measurement requirements of next-generation large satellite antennas.

Conclusions:

• The integrated laser distance measuring and DIC method provides a viable solution for precise 3D deformation monitoring of large satellite antennas.
• The vibration compensation strategy enhances measurement accuracy in unstable environments.
• This technique is crucial for maintaining and improving the performance of future large-aperture spaceborne SAR systems.