A multilateral synthetic aperture wireless positioning approach to precise 3D localization of a robot tool center point

In this paper, a novel multilateral synthetic aperture secondary radar concept and its application for precise 3D localization of a robot tool center point (TCP) are introduced. A backscatter transponder is attached to the TCP of a robot. Spatially distributed FMCW secondary radar units pick up the backscattered phase coherent transponder signals. Based on assisting relative sensors, a synthetic aperture is created with the TCP. The developed multilateral inverse synthetic aperture reconstruction algorithm then determines a probability density function (PDF) of the spatial transponder position. By simulations and experimental results using a 5.8 GHz system with 140 MHz bandwidth it is shown, that 3D localization precision in the mm range can be achieved with the novel wireless local positioning concept even with narrowband radar systems in dense multipath environments. Heretofore, accuracies of this magnitude were only attainable with ultrawideband (UWB) systems utilizing a ten times wider bandwidth. It is shown, that the multilateral synthetic aperture locating system has the potential for a quantum leap in precise 3D wireless local positioning.