## 3 Data Used  
With the Xiaomi Mi 8 and Samsung Galaxy S21 Ultra, dual-frequency signals (L1 and L5) can be tracked in addition to multiple constellations (GPS, GLONASS, Galileo, and BeiDou). An application called GnssLogger (Google) 3.0.6.4 version was used to simultaneously record the INS measurements and the raw GNSS observations for the experiment. A more realistic driving simulation can be achieved by mounting the smartphones on the dashboard rather than the vehicle's roof (Figure 2b). This study assumes that the INS frame remains stationary with respect to the vehicle's frame throughout. The Xiaomi Mi 8 is also equipped with the InvenSense ICM-20690 IMU model, while the Samsung Galaxy S21 Ultra uses the ST-Microelectronics LSM6 DSO IMU model. This study was a Stonex geodetic receiver, model S3 II SE, manufactured by Stonex, located in Milan, Italy as a reference station (Figure 2c). The car's maximum distance from the reference station was 2 km. This is because, for short baselines of less than 5 km, the additional double-differenced ionospheric and tropospheric delays can also be disregarded [39; 40]. On the other hand, the U-Blox receiver, model ZED-F9R, manufactured by U-Blox, located in Thalwil, Switzerland, which was placed on the car's roof by an antenna (Figure 2a,d), and connected to [PERSON]'s Continuously Operating Reference Stations (CORSs) network on the Internet, which was used to compare the positions obtained from smartphones with the desired methods. This study was accomplished in Qazvin City in Iran, with the entire path shown in Figure 3.  
Figure 1: Flowchart depicting the TC RTK/INS integration architecture.  
This study operates under the assumption that the IMU frame remains fixed in relation to the vehicle frame for the entire duration of the experiment. Smartphones come with inertial sensors designed for consumer use, and their specifications are outlined in Table 1. Consequently, these smartphone IMUs are expected to bridge shorter periods of navigation outage in GNSS-denied scenarios. Specifically, for the IMU featured in the Galaxy S21 Ultra model, the factory datasheet and existing literature do not provide information on in-run bias. Therefore, future research could involve static IMU testing to calculate the Allan variance.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Phone Models** & **Xiaomi Miß** & **Samsung Galaxy S21 Ultra** \\ \hline IMU Model & InvenSense ICM-20690 & ST-Microelectronics LSM6 DSO \\ \hline \multicolumn{3}{c}{Gyroscope} \\ \hline In-run bias stability (\(\lx@math@degree\)/h) & \(>\)1000 & - \\ \hline Noise density (\(\lx@math@degree\)/s/\(\surd\)Hz) & 0.004 & 0.004 \\ \hline Standard full range (\(\pm\lx@math@degree\)/s) & 2000 & 2000 \\ \hline \multicolumn{3}{c}{Accelerometer} \\ \hline In-run bias stability (mg) & 40 & - \\ \hline Noise density (mg/\(\surd\)Hz) & 100 & 110 \\ \hline Standard full range (\(\pm\)g) & 16 & 16 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Factory specifications of the inertial sensors used.  
Figure 2: The U-Blox antenna installed on the car roof (**a**), the Xiaomi Miß (left) and Samsung Galaxy S21 Ultra (right) mounted in the car (**b**), the Stonex S3 II SE geodetic receiver (**c**), and the ZED-F9R receiver chipset used for the U-Blox antenna (**d**).