An Ultra-Wideband Autonomous Integrity Monitoring Algorithm Based on Post-Test Residuals

The high-precision positioning technology, Global Navigation Satellite System (GNSS), has found extensive applications in various outdoor fields. However, it often faces limitations when used indoors due to the unreliable availability of GNSS signals. Ultra-wideband (UWB) technology, known for its high resolution and good penetration capabilities, is suitable for indoor positioning. However, the existing UWB positioning methods lack robustness and error tolerance. To address these issues and ensure reliable indoor positioning, this paper introduces an integrity monitoring algorithm based on existing UWB positioning methods. From a post-test perspective, this integrity monitoring algorithm is used to identify faulty anchor nodes and downweight the range measurements corresponding to epochs with test statistics exceeding a threshold. Experimental results demonstrate that this method can effectively eliminate system errors and significant accidental errors, significantly improving positioning accuracy. In static experiments where the true values were determined using a total station, the planar errors for two mobile stations (tags) after applying this method were 2.4 cm and 2.3 cm, respectively, representing an improvement of around 80% compared to traditional methods. In dynamic experiments, the results obtained using this method closely matched the reference trajectory.