Indoor GNSS Weighted Positioning With Fourfrequency Division Relayed by Four-Antennas

To address the failure of traditional GNSS positioning in indoor environments due to severe satellite signal attenuation, this paper proposes a weighted indoor GNSS positioning with frequency division relayed by four-antennas (4 A FDR). A frequency-division forwarding system architecture is designed, where multi-band satellite signals captured by outdoor radio frequency ($\mathbf{R F}$) front-ends are retransmitted via four indoor antennas dedicated to the GPS-L1, BDS-B1, GLONASS-G1, and GPS-L5 frequency bands, respectively. At the indoor receiver end, three-dimensional positioning is achieved using multi-band pseudorange differences. A Weighted Least Squares (WLS) model is constructed by integrating multi-band pseudorange noise observations, and the positioning solution is optimized through dynamic adjustment of pseudorange noise weight matrices for different satellite systems. Simulation experiments demonstrate that in a $\mathbf{5 0 m} \boldsymbol{\times} \mathbf{5 0 m} \boldsymbol{\times} \mathbf{3 0 m}$ indoor scenario, the positioning error achieves meter-level accuracy. This method provides a viable positioning solution for complex indoor environments such as airports and underground parking lots.