Simulation-Based Performance Analysis of Seamless Indoor-Outdoor Navigation Using a Single-Transmitter-Based Positioning System

While Global Navigation Satellite Systems (GNSS) provide reliable outdoor positioning, establishing a representative method for indoor environments remains challenging due to signal blockage and structural complexity. This paper presents a three-dimensional indoor positioning algorithm based on carrier phase measurements from a single transmitter equipped with an antenna array. This approach ensures high precision, scalability, and maintainability while remaining compatible with existing GNSS receivers. However, single-transmitter systems suffer from poor Dilution of Precision (DOP) and geometric errors when the user’s height is unknown. To address this, the proposed algorithm incorporates auxiliary constraints, specifically user height and distance (Round-Trip Time). Performance was evaluated via simulations across three scenarios: known height, known distance, and a combination of both. A ray-tracing method was employed to accurately model significant indoor multipath errors, and a Kalman filter was utilized to fuse measurements and mitigate noise. Furthermore, this study proposes a unified framework for seamless indoor–outdoor positioning. In transition areas, the system applies an adaptive weighting scheme based on C/N? and signal strength to integrate the indoor algorithm with conventional outdoor GNSS. Simulation results, which account for severe multipath effects in transition zones, demonstrate that the proposed method significantly enhances accuracy and continuity. This comprehensive approach offers a robust solution for precise navigation in complex indoor environments and transition areas.