Handheld Mobile Mapping using Smartphones

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This dissertation proposes a low-cost, handheld mobile mapping system (MMS) using smartphones. The current generation of smartphones is equipped with low-cost GPS receivers, high-resolution digital cameras, and micro-electro mechanical systems (MEMS)-based navigation sensors (e.g., accelerometers, gyroscopes, magnetic compasses, and barometers). These sensors are in fact the essential components for a MMS. However, smartphone navigation sensors suffer from the poor accuracy of global navigation satellite system (GNSS), accumulated drift, and high noise to signal ratio that are associated with inertial measurement unite (IMU). These issues affect the accuracy of the initial exterior orientation parameters (EOPs) that are input into the bundle adjustment algorithm, which then produces inaccurate 3D mapping solutions. First, the law of error propagation of variance is used to estimate the theoretical accuracy of using smartphones as handheld MMS. Then, robust sensors calibration is carried out to eliminate the deterministic errors associated with each sensor. Afterward, new methodologies are proposed to increase the accuracy of direct geo-referencing of smartphones. The prototype system was started by developing an iOS application that was to capture synchronized images with GPS and motion sensors measurements. The geo-referencing of captured mapping images was verified and improved using the proposed methodologies. This system was evaluated against ground truth data in different environments. In the absence of GPS multipath error, the RMSE of the system absolute accuracy is 3-4 meters in the horizontal direction and 13 meters in vertical direction. Furthermore, the RMSE of the system relative accuracy is 5 centimeters in the case of having more than 3 intersected light rays.
Mobile mapping system, Smartphones, Photogrammetry, Free network bundle adjustment, GNSS, IMU
Alsubaie, N. M. (2018). Handheld Mobile Mapping using Smartphones (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/13060