An Evaluation of the Accuracy of GNSS Receivers Integrated with MEMS-IMU Sensors for Optimal Angle Determination in Tilted Observation Scenarios Using the NRTK GNSS Technique in Thailand

Abstract

This paper evaluates the performance and accuracy of GNSS receivers integrated with MEMS-IMU sensors for optimal angle determination in tilted observation scenarios within obstructed environments. Utilizing the Network-based RTK (NRTK) GNSS technique, two GNSS receiver brands, Tersus Oscar (OS) and e-Survey E600, were tested at various tilt angles, ranging from 0° to 60°, at specific locations on the rooftop of the Engineering Building at Chulalongkorn University, Bangkok, Thailand. These test points included open areas and obstructed positions, such as corners and doors, where satellite visibility is reduced. The study assesses the Root Mean Square Error (RMSE) in both horizontal and vertical positions, as well as the Position Dilution of Precision (PDOP). Results indicate that horizontal accuracy decreases with increased tilt angles in obstructed environments, with the 'Door' point showing the highest errors due to significant obstructions. Conversely, 'Corner right' consistently demonstrates superior accuracy across all conditions. The integration of tilt-compensation technology is shown to improve positioning precision, especially in challenging environments where physical obstructions affect satellite signal reception. This research provides valuable insights for improving the accuracy of GNSS-based cadastral surveys and other high-precision applications in obstructed environments.