Indoor Positioning Algorithm for Complex Environments

In order to solve the problems of large fluctuations in traditional UWB positioning errors and significant cumulative errors of inertial navigation in complex scenarios such as shopping mall corridors and underground garages, this study proposed a positioning framework based on tight coupling of ultra-wideband, lidar and IMU. By deploying a UWB network calibrated with dual base station topology, the LeGO-LOAM algorithm is used to process the Velodyne VLP-16 lidar point cloud to generate 3D constraints; IMU data is fused by improving the pre-integration model; and a two-layer optimizer is designed (factor graph optimization based on sliding windows at the front end and GTSAM batch optimization accelerated by CUDA at the back end) to achieve spatiotemporal alignment of multiple sensors. The measured data show that in a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$200 ~\mathrm{m} \times 80 ~\mathrm{m}$</tex> underground garage, the standard deviation of the continuous positioning error of dynamic targets is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{0. 1 7}$</tex> meters, the maximum error is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{0. 5 3}$</tex> meters, and the cumulative error is controlled within 0.32 meters in a 15 -minute long test. In the metal curtain wall corridor scenario, the algorithm successfully suppresses the multipath effect, the positioning success rate reaches 98.7 %, and the calculation time is stable at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{2 8} \boldsymbol{\pm} \mathbf{3 m s}$</tex> (Jetson AGX Xavier platform. The conclusion proves that the architecture significantly improves the positioning robustness in complex dynamic environments through the hardware layer topology optimization and the algorithm layer tight coupling design, meeting the millimeter-level operation requirements of automatic guided vehicles.