Estimating Urban Road GPS Environment Friendliness with Bus Trajectories: A City-Scale Approach

Abstract

GPS is taken as the most prevalent positioning system in practice. However, in urban areas, as the GPS satellite signal could be blocked by buildings, the GPS positioning is not accurate due to multi-path errors. Estimating the negative impact of urban environments on GPS accuracy, that is the GPS environment friendliness (GEF) in this paper, will help to predict the GPS errors in different road segments. It enhances user experiences of location-based services and helps to determine where to deploy auxiliary assistant positioning devices. In this paper, we propose a method of processing and analysing massive historical bus GPS trajectory data to estimate the urban road GEF integrated with the contextual information of roads. First, our approach takes full advantage of the particular feature that bus routes are fixed to improve the performance of map matching. In order to estimate the GEF of all roads fairly and reasonably, the method estimates the GPS positioning error of each bus on the roads that are not covered by its route, by taking POIinformation, tag information of roads, and building layout information into account. Finally, we utilize a weighted estimation strategy to calculate the GEF of each road based on the GPS positioning performance of all buses. Based on one month of GPS trajectory data of 4835 buses within the second ring road in Chengdu, China, we estimate the GEF of 8831 different road segments and verify the rationality of the results by satellite maps, street views, and field tests.

Mobile Sensing Around the Globe: Considerations for Cross-Cultural Research

“…Furthermore, environmental factors that can directly affect sensor performance may vary systematically across cultural regions. For example, motion sensor readings can be skewed in warmer climates (e.g., Kos et al, 2016) and GPS signals can be blocked by buildings or trees (e.g., Ma et al, 2020;Bastos & Hasegawa, 2013).…”

A Geometric Approach to Noisy EDM Resolution in FTM Measurements

“…For example, Liu et al [7] proposed using detection of the building and comparison with publicly available aerial imagery to revert to meter precision. Other authors propose to use the known degradation pattern of the signal [8,9] to adjust the location calculation. Our measurements in this paper show that accuracy can be maintained at a sub-meter level in many cases, even near buildings.…”