Phoenix Mobile Experimental Platform

Research Group Robotics & Process Control

Global Scan Matching

APR (Anchor Point Relation Matching) as a basic scan matching technique in the CAROL project determines for an actual laser scan its most likely matches in a set of reference scans. All necessary computations are done in realtime.

The picture shows a set of 30 reference scans taken in our lab environment. For visualization purposes the reference scans are fitted into a global coordinate system. The gray triangles and the black line connecting them indicate the track of Phoenix' tour through the lab. Each gray triangle indicates a robot position where the algorithm determined the correct corresponding reference scan and the correct robot position in its local coordinate system. Black triangles indicate wrong position hypotheses. All scan matches were global, i.e. no assumptions about the current position were taken into account to determine the most likely matching reference scan for the actual laser scan.

In the example presented here, for a total of 1405 laser scans 831 correct and 1 wrong position hypotheses were generated.

During self-localization, these matching results are used to confirm or reject position hypotheses from other sources, and to create completely new position estimates.

Implementation: Joachim Weber

Publications: