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Improving the accuracy of real-time smartphone positioning in urban environments using raw GNSS observations
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Amir Hossein Pourmina *   , M.Mahdi Alizadeh |
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Abstract: (82 Views) |
The GNSS sensors of some smartphones can provide pseudorange, Doppler, carrier phase, and other satellite observation data in real-time at 1 Hz. Additionally, smartphones can receive broadcast data from the network through the reference station. This study used Samsung Galaxy S21 Ultra and Xiaomi Mi8 smartphones in static and kinematic conditions mounted on an appropriate stand inside a car. GNSS U-Blox receiver model ZED-F9P was used to compare smartphone positioning with PPK, SPP, and Fusion methods. The results showed that multipath error and noise caused multiple phase jumps in the observations of the Mi8 smartphone, reducing the accuracy of the results obtained from the PPK method on streets with high buildings compared to the SPP method.
Nevertheless, the PPK algorithm was superior to the SPP algorithm on streets without high-rise buildings, even when using the Mi8 smartphone. Conversely, in the S21 Ultra, the results were consistently more accurate than the SPP method, which can be attributed to its superior antenna compared to the Mi8. As a result of integrating the extended Kalman filter (EKF) and INS observations, outlier observations are identified and removed, resulting in higher accuracy compared to the PPK and SPP methods. Using smartphones to determine position in streets with high-rise buildings, such as Khayam and Naderi streets in Qazvin city, the accuracy of determining the position reached 6 meters. With the Fusion method, an accuracy of about 2 meters can be achieved on streets with mid-rise buildings. |
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| Keywords: Post-Processing Kinematic, smartphone, GNSS, Fusion method. |
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Type of Study: Research |
Subject:
Geodesy
Received: 2023/02/23 | Accepted: 2023/09/13 | ePublished ahead of print: 2024/10/29
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