An IMU/UWB tightly coupled navigation algorithm to improve positioning accuracy under large-scale NLOS conditions

Abstract Low-cost, high-precision indoor positioning systems are becoming crucial in some applications such as smart manufacturing, logistics and warehousing, pedestrian tracking and embodied artificial intelligence. Ultrawideband (UWB)-based ranging techniques offer advantages like short pulse intervals and high temporal resolution, but non-line-of-sight (NLOS) occlusion can limit their performance and application scope. Low-cost inertial measurement units (IMUs) provide accurate navigation information over short periods but suffer from error accumulation. To address these issues, this paper propose a IMU/UWB tightly coupled navigation algorithm combining carrier motion characteristics. In line-of-sight (LOS) environments, the precise positioning information from UWB assists in correcting the accumulated error of IMU. In NLOS environments, the corrected inertial navigation system (INS) information improves the system’s robustness and accuracy. Additionally, we incorporate the carrier motion information into the INS using the extended Kalman filter algorithm and use the results for NLOS determination. The experimental results show that the tight coupling algorithm proposed in this paper can effectively eliminate the accumulated error of IMU. Under LOS conditions, the root mean square error is reduced by 29.9% compared with single UWB positioning. At the same time, the large-scale NLOS problem is solved while ensuring positioning accuracy. This method can reduce the deployment density of base stations in practical applications, expand the effective positioning range of the system, and make positioning in some NLOS areas possible.