Overlap displacement error: Are your SLAM poses map-consistent?

Localization is an essential module that supports many intelligent functions of a mobile robot such as transportation or inspection. However, justifying that a localization module is sufficiently accurate for supporting all downstream tasks is one of the most difficult questions to answer in practice. To overcome this problem, we move away from the traditional calculation of pose errors and propose a new approach that instead evaluates the potential map inconsistency introduced by those pose errors. For this purpose, we propose a new metric, which we call Overlap Displacement Error (ODE). This metric measures the relative displacements between multiple overlapping sensor frustums with respect to the ground truth. All you need to compute this metric are a query trajectory, a ground truth trajectory and the sensor frustum used for mapping. Having the sensor frustum and the map representation as part of the metric, the ODE is customized to the hardware configuration and the mapping strategy. This design allows the analysis of pose accuracy in a space that matters to map creation, and also allows the identification of problems sitting in the interplay between localization and mapping. We demonstrate the potential of this new analysis tool on synthetic and the real-world sequences.