A Sub-meter Accurate Positioning using 5G Double-difference Carrier Phase Measurements

Apart from communications, the Fifth Generation (5G) technology is also motivated by positioning requirements down to the sub-meter level across industry verticals. In this work, we utilize Universal Software Radio Peripheral to transmit and receive the 5G New Radio signals. The obtained samples are then processed by the proposed 5G code and carrier phase software defined receiver. In this process, the dedicated 5G Positioning Reference Signal (PRS) is adopted to obtain time of arrival estimates using more accurate carrier phase measurements instead of code phase measurements. The continuously transmitted 5G PRSs over time enable accurate carrier phase tracking and avoid ambiguity problems during the tracking stage in line-of-sight environments. Furthermore, a roadside unit is set up to observe the same signals and cancel out the measurement error introduced by the clock offset between two transmitters. Finally, some field experiments are carried out, and the experimental results indicate that using 5G double-difference carrier phase measurements from only four transmitters, a position root mean square error of 0.790m is achievable.