HTC Vive as a Ground-Truth System for Anchor-Based Indoor Localization

The last decade has seen a surge in the popularity of indoor localization systems. Researchers and companies keep searching for technologies that can locate users on a large scale with low costs and the highest possible accuracy. When evaluating the accuracy of a localization system, there is a trade-off between the cost and labor involved in acquiring ground-truth measurements. The cheapest option is to acquire measurements in fixed spots and manually compute their true location in a local coordinate system using distance measuring tools. However, this method is prone to human errors and has a high setup overhead. In contrast, high-end motion capture systems are easy to set up but have prohibitive prices. A middle-of-the-road solution is to use a consumer-grade motion capture system such as the HTC Vive which, although designed for virtual reality video games, can be adapted for scientific applications. We propose a ground-truth system for anchor-based indoor localization systems which builds on the HTC Vive and we demonstrate its use on ultra-wideband (UWB) localization. We apply Procrustes Analysis to bring location data sets into the coordinate system of a room, in order to easily overlap, visualize, and analyze measurements. We use the HTC Vive to acquire the locations of UWB anchors, which allows users to quickly test which hardware placement yields the lowest localization error. The resulting ground-truth system costs under $1000, has an average accuracy of more than 5 mm, is easy to set up, and can be used for both static and dynamic measurements.