A Multi-Robot Large Antenna Positioning System for Over-The-Air Testing at NIST
Authors: David R. Novotny, Joshua A. Gordon, Michel S. Allman, Alexandra E. Curtin, Jeff R. Guerrieri, Kim Hassett, Quang Ton, George McAdams
Publication: AMTA 2017
Copyright Owners: NSI-MI Technologies, NIST | Communications Technology Laboratory
To address dynamic testing requirements of new communications systems and RF processes that use non-static beam forming, NIST proposed the Large Antenna Positioning System (LAPS). The LAPS consists of two kinematically-linked six axis robotic arms, one of which is integrated with a 7 m linear rail system. This repositionable, multi-robot system can perform arbitrary scans around a device under test. The dynamic 13 degree-of-motion capability is designed to perform complex spatial interrogation of systems.
The coordinated-motion capabilities of the system are key to support not only traditional antenna measurement geometries (i.e. spherical, cylindrical, planar, gain-extrapolation), but are also intended to be used to dynamically interact with changing RF conditions. The robots can independently scan or interrogate multiple bearings toward a device under test, perform MIMO illumination, or trace out complex 6D paths during system testing.
Initial RF and mechanical testing results in the factory where it was built show deviations from an ideal linear scan at 0.032 ± 0.02 mm, much better than the l/50 system design specification at 30 GHz. Further improvements to the basic kinematic models of each robot will allow this generation of robotic antenna range to operate open loop without laser tracker feedback.