This invention relates to the field of
wireless positioning technology, specifically disclosing a method for improving indoor positioning accuracy by fusing Wi-Fi,
Bluetooth, and 4G signals. The method first synchronously collects and timestamps-aligns Wi-Fi,
Bluetooth, and 4G signals and data; then, it extracts distance or location observations and dynamically evaluates the uncertainty of each observation; next, it constructs a
factor graph-based fusion model, applying the inertial factor generated by pre-integration and the observation factor generated by the
wireless signal to the terminal state node to be determined; finally, through nonlinear optimization, it solves for the optimal motion trajectory in one step. This invention deeply fuses heterogeneous signals using a probabilistic
graphical model, utilizes the wide-
area coverage of 4G to compensate for the blind spots of Wi-Fi /
Bluetooth, uses the continuity to smooth the fluctuations of
wireless signals, and intelligently allocates weights through uncertainty modeling, ultimately achieving comprehensive coverage, high accuracy, and strong robustness in indoor positioning.