Mutual Registration-Based Multi-Member Collaborative Localization with UWB for Foot-Mounted Inertial Navigation

Accurate team positioning in GNSS-denied environments is essential for military, rescue, and industrial operations. This paper presents a mutual registration-based collaborative algorithm for inertial navigation systems that eliminates reliance on external infrastructure. Specifically, an accelerometer bias estimation-based zero-velocity update (ABE-ZUPT) algorithm is introduced to mitigate velocity drifts and enable precise dead reckoning. Additionally, when ultrawideband (UWB) ranging and position information sharing are conducted among some members, mutual registration is performed to correct the accumulated errors in heading and position estimation. Field experiments in urban road areas with multiple members demonstrate that our algorithm achieves a significant improvement in positioning accuracy over standalone and the conventional EKF-based cooperative methods: In a 1,115-meter long-distance test (Trial 1), collaborative positioning reduced closure errors by 87.17% (28.91 m → 3.71 m) and average errors by 67.57% (19.09 m → 6.19 m) compared to standalone estimation. For complex maneuvers (Trial 2, a 107-m circular path with rapid turns), we achieved a 50% reduction in closure error (1.30 m → 0.65 m) and a 29.45% average error reduction (1.46 m → 1.03 m). Additionally, we conducted experimental validation of anti-interference performance and member scalability, achieving favorable results. These validate our method as a robust solution for high-precision collaborative positioning in GNSS-denied environments.