On the feasibility of real-time phone-to-phone 3D localization

Abstract

High-speed, locational, phone-to-phone (HLPP) games and apps constitute a provocative class of mobile apps that are currently unsupported on commodity mobile devices. This work looks at a key problem for enabling HLPP: a specific variant of the localization problem in which two phones estimate each other's relative positions in 3D space without infrastructure support. Moreover, position estimates should reflect changes due to the phones' possible mobility.We present a solution for achieving high speed 3D continuous localization for phone-to-phone scenarios. Our basic approach uses acoustic cues based on time-of-arrival and power level. It assumes at least two microphones and one speaker per phone, which is common on new smartphones. Accelerometers and digital compasses assist in resolving ambiguous acoustic-only localization. Continuous localization is achieved with the aid of a loose time synchronization protocol and an extended Kalman filter. Experimental results across a range of motion paths show localization resolution to within 13.9 centimeters for 90% of estimates, and to within 4.9 centimeters for 50% of estimates when the phones are several meters apart.

Collocated Multi-user Gestural Interactions with Unmodified Wearable Devices

“…Another approach is Microsoft's BeepBeep system [33,34] which uses two-way acoustic ranging for calculating the positions of several devices relative to each other. This ranging method has been explored and optimized in different ways [6,32,36], and also lays the basis for our interaction technique.…”

Push the limit of WiFi based localization for smartphones

“…It avoids tight synchronization usually required in Time Difference of Arrival (TDoA) methods. Qiu et al [22] utilizes the acoustic signal to estimate the relative position between two phones to support phoneto-phone games and apps.…”

Montage: Combine frames with movement continuity for realtime multi-user tracking

“…Peng et al [18] proposed ETOA with centimeter-level accuracy acoustic-based pair-wise ranging method. [19] presents a solution for achieving high speed 3D continuous pair-wise localization using two microphones and one speaker on the phone. Liu et al [13] uses acoustic ranging estimates among peer phones as constraints to reduce the significant errors of WiFi-based method.…”

“…Another category of approaches are range-based using different metrics. The acoustic based methods on commercial mobile handset address the issue of meter-level pair-wise ranging, e.g., [18], [19]. Some other solutions use code division multiple access (CDMA) acoustic telemetry to simultaneously monitor the movements of numerous individual users, e.g., [1], [8], [16].…”