Kayak-specific Motion Constraints for an Improved Android Smartphone GPS/INS Navigation Solution
Date
2022-08
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Abstract
In this thesis, a Global Positioning System (GPS) / inertial navigation system (INS) smartphone navigation solution to track a kayak accurately and continuously down a river is developed, implemented, and tested. A Google Pixel 4 was used to log raw GPS, accelerometer, and gyroscope measurements. Four field datasets were collected with commercial grade GNSS receivers for a reference solution and the smartphone fixed to the deck of a kayak. Traditional closed loop loosely and tightly coupled GPS/INS algorithms were compared. Both implementations were found to perform similarly with complete satellite coverage and both degraded rapidly in the event of a GPS outage. GPS signal outages may frequently occur on a river due to vegetation, canyon walls, and water splashing over the receiver and the solution becomes reliant on the INS alone. Low-cost inertial sensors, such as those found in a smartphone, were incapable of providing an accurate solution for a long period of time during GPS outages due to the accumulation of sensor errors. To minimize this INS error, the motion of a kayak was analyzed and constraints exclusive to kayaking were proposed to improve the solution. These kayak-specific motion constraints estimated the gyroscope bias, pitch and roll angles, and accelerometer bias based on the assumption that the kayak’s pitch and roll angles are centered around zero, cyclic in nature, and return to the same orientation at regular time intervals. These motion constraints were applied to the collected datasets in a loosely coupled filter to verify this solution. The velocity and position errors during a GPS outage were improved with motion constraints as opposed to a traditional filter without motion constraints. After a simulated 20 second GPS outage on one dataset, the horizontal and vertical errors improved from 31.077 to 12.538 metres and 8.874 to 1.342 metres respectively with the motion constraints applied. This improvement was verified with three additional datasets. Therefore, the proposed kayak-specific motion constraints were found to improve the GPS/INS navigation solution, particularly during a GPS outage.
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Keywords
Smartphone positioning, GPS, inertial navigation, GPS/INS, motion constraints, kayaking
Citation
Harke, K. (2022). Kayak-specific motion constraints for an improved Android smartphone GPS/INS navigation solution (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.