A Reality Check of Positioning in Multiuser Mobile Augmented Reality: Measurement and Analysis

Multiuser Augmented Reality (MuAR) is essential to implementing the vision of Metaverse. With the pervasive mobile devices, MuAR enables multiple devices to share a common AR experience. In such experiences, the peer positions are critical to understand peers' intentions and actions so as to achieve the smooth interaction in AR. Such a spacial awareness requirement poses new challenges to MuAR. Traditionally, in AR experiences designed for the single user, the SLAM algorithm is adopted to compute self positions. However, the computed positions cannot be directly used to compute the relative positions of peer devices in MuAR, because they are computed with respect to independent coordinate systems associated with participating devices. To fill in the gap, the industry has recently proposed to implement peer tracking with the help of built-in Ultra Wideband (UWB) chip. In this work, we aim to perform a reality check on the proposed support, with the Nearby Interaction (NI) framework developed for iOS mobile devices as an example. The goal of our study is to gain an in-depth understanding about the reliability of the proposed support and identify potential issues. Through extensive measurements, we discover the peer tracking solution is not reliable sometimes, in terms of availability and accuracy. Furthermore, with regard to erroneous position reports, we present a quantitative analysis, summarizing the error types (e.g., transient errors and permanent errors) and revealing their underlying reasons. We believe the preliminary findings could help to improve the spacial awareness and enhance user experiences in MuAR.