Achieving Impressive Global Positioning and Stability in a High Fidelity Antenna Measurement System
Author: Jacob Kunz, Eric Kim
Highly accurate antenna measurements can require precise alignment and positioning of the probe antenna to the antenna under test. The positioning of the antenna during acquisition can involve the movement of several simultaneous axes of motion. This places a global positioning accuracy requirement on the positioning system. To achieve precision in global positioning and alignment, an understanding of dominant error factors such as load induced deflection/resonance, thermal deflection, positioning error sources and mechanical alignment tolerances is essential. This paper focuses on how global accuracy and stability were achieved, addressing these factors, on a recently delivered large far field antenna measurement system. The system involved eight axes of positioning with the ability to position 950 lbs. antenna under test 5.94 meters above the chamber floor achieving 0.84 mm and 0.027 degrees positioning accuracy relative to the global range coordinate system. Stability of the probe antenna after motion was within 0.076 mm.