The study on the relationship between ionospheric delay and low-cost localizing robots

Abstract

The dispersive and anisotropic nature of the ionosphere above certain regions particularly on Thailand's low − nearly equatorial − latitude, positioning accuracy is seriously affected when using a precision limited model. Change in ionospheric delay is a key factor impacting the Global Navigation Satellite Systems (GNSS) positioning and navigation accuracy. We studied the effect of ionospheric delay on localizing low-cost robots. We investigated the positioning error using ionospheric delay from a GNSS receiver, IRI and our campus, KMITL, in Bangkok, to guide our ‘G-LOC’ robot. There were eight target points, set from 3 to 50 m at the same meridian with varying latitudes. Impacts on a robot moving on low solar activity days, high solar activity days, daytime, and nighttime were measured over 12 months in 2023. We found that high solar activity day impacts a robot moving on highest accuracy error up to 363 cm at high speed. In addition, we found that daytime impacts a robot moving on highest accuracy error up to 154.05 cm at high speed as well. Ionospheric delay according to high and low solar activities, and daytime, and nighttime effects on the GNSS interference transmitted to a low-cost localizing robot was expected to affect moving errors, but it did not seem to lead to a significant difference in error between the low and high solar activity days.