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A car was equipped with the cellular LTE navigation receiver discussed in Section 38.6.2. The receiver was tuned to the cellular carrier frequencies 739 MHz and 1955 MHz, which are used by the US cellular provider AT&T. The PLL, FLL, and DLL noise‐equivalent bandwidths were set to 4, 0.2, and 0.001 Hz, respectively. The adaptive threshold approach proposed in [65] was adopted to mitigate multipath.

All measurements and trajectories were projected onto a 2D plane. It was assumed that the receiver had access to GPS, and GPS was cut off at the start time of the experiment. Therefore, the EKF’s states were initialized with the values obtained from the GPS navigation solution. The standard deviation of the initial uncertainty of position and velocity were set to be 5 m and 0.01 m/s, respectively [55]. The standard deviation of the initial uncertainty of the clock bias and drift were set to be 0.1 m and 0.01 m/s, which were obtained empirically. The clock oscillators were modeled as oven‐controlled crystal oscillators (OCXOs) with and , where h₀ = 2.6 × 10⁻²² and h₋₂ = 4 × 10⁻²⁶. The power spectral densities and were set to 0.2 m²/s³, and the measurement noise covariance was set to be 10 m², which were obtained empirically. The vehicle was listening to six eNodeBs whose position states were mapped beforehand. The cell IDs of the eNodeBs were 216, 489, 457, 288, 232, 152, respectively. The first three eNodeBs had a 20 MHz transmission bandwidth, and the rest of the eNodeBs had a 10 MHz transmission bandwidth. The C/N₀ for all received eNodeB signals was between 50 and 68 dB‐Hz. The experimental hardware setup, the environment layout, and the true and estimated navigator trajectories are shown in Figure 38.52. The ground‐truth trajectory was obtained from the GRID GPS SDR [58].