摘要:
GPS是应用最为广泛的室外定位系统，随着技术的发展精度不断提升.然而城市中，由于GPS卫星信号被建筑遮挡，仍然可能产生较大的多径误差.此类误差已称为城市GPS定位误差的主要成分.评估城市道路中环境对GPS精度的负面影响，即环境的GPS友好度，将有助于对不同地段GPS的误差范围进行预判，从而提升位置服务相关应用的用户体验，并为理解环境特征与多径误差的关系，确定在何处部署辅助定位的设备提供支持.为此，提出了1种通过处理和分析海量公交车GPS轨迹历史数据，从而评估城市主要路段的环境友好性的方法.该方法充分利用公交车运行线路固定的特点，大幅提升数据处理的效率；针对路网数据可能存在的错误，提出了容错性的方案；利用相同车辆及相同路段在GPS误差上存在的内在关联，对缺失数据进行补全；并充分考虑到不同质量GPS端设备对环境友好性评估的影响，确定了基于端设备质量加权的评估计算策略.利用成都市二环内的4869辆公交车1个月的数据，对共计5648个不同路段的环境友好性进行了评估，并通过卫星地图和街景照片，分析验证了方法结果的合理性.
Abstract:
GPS is the most widely-used outdoor positioning system. With the advance of relevant technologies, positioning accuracy of GPS has been increasing continuously. However, as the GPS satellite signal can be blocked by buildings, multi-path error becomes the major cause of positioning error in a city. Evaluating the negative effects of GPS error on urban environments, which is referred as environment friendliness in this paper, will help the prediction of GPS error range in different road segments. Furthermore, it enhances user experiences of location-based services, reveals the relationship between environmental characteristics and multi-path error, and helps to determine where to deploy supplementary positioning devices. In this paper, we have proposed an urban road friendliness evaluation (URFE) approach, based on the processing and analyzing of massive historical bus GPS trajectory data. Specifically, URFE first takes full advantage of the unique features of fixed bus routes to significantly improve the efficiency of data processing. Then, it adopts a fault-tolerant method to deal with the possible errors of street maps; Finally, URFE completes the missing data by utilizing the inherent relationship between GPS errors of the same cars and roads, and utilizes an evaluation strategy by taking the influence of different GPS terminal devices’ qualities into account. Using the bus trajectory data within the second ring road of Chengdu during one month, we evaluate the effectiveness of our approach. Environments friendliness of 5648 different road segments has been evaluated, whose rationality has been verified by checking real satellite maps and street views.
百度学术
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