ISBN 9783843920148

978-3-8439-2014-8, Reihe Elektrotechnik

Gang Li
Innovative Imaging Synthetic Aperture Secondary Radar Concepts for Ultra-Precise Positioning and Tracking of a Backscatter Transponder in Multipath Environments

146 Seiten, Dissertation Universität Erlangen-Nürnberg (2014), Softcover, A5

Zusammenfassung / Abstract

In this work, novel synthetic aperture based imaging secondary radar positioning and tracking concepts are introduced. The proposed approaches allow for ultra-precise localization of a backscatter transponder even in severe multipath environments. During a test run, the backscatter transponder is carried by the TCP (tool center point) of a robot arm. Multiple spatially distributed radar units gather signals at different positions and different times. The transponder motion is measured during a short period of TCP movement by an assisting sensor, e.g., an IMU (inertial measurement unit) or rotational encoder. The developed MISAS(multilateral inverse synthetic aperture secondary radar) algorithm adopts the spatial matched filter principle for multipath mitigation based on a synthetic aperture reconstruction. With a short aperture of several centimeters, the reconstructed image is adaptively focused on the transponder position, while multipath corruptions are effectively suppressed. The image fusion of all radar units provides an unambiguous PDF (probability density function) of the transponder position with the use of a PDF-based multilateration approach. The robot multipath channel was measured in a test campaign and subsequently used for multipath simulations. The simulation results show that millimeter-accurate MISAS localization with a narrow bandwidth signal of 5.73 to 5.87 GHz is achievable even in a dense multipath scenario. Experiments on a lightweight as well as a rigid robotic arm provided nearly 1.5 mm average localization accuracy. The improvement factor is more than 100 in contrast to classical lateration-based approaches.