Utility of global positioning system to measure active transport in urban areas
Utility of global positioning system to measure active transport in urban areas
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DOI：
10.1249/mss.0b013e31811ff31e
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发表时间：
2007-10-01
期刊：
影响因子：
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通讯作者：
Dascombe, Ben J.
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文献类型：
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作者：
Duncan, Mitch J.;Mummery, W. Kerry;Dascombe, Ben J.
目的：本研究的目的是确定全球定位系统（GPS）单位测量步行和骑自行车（AT）时行驶的距离的重测信度，并确定GPS单位的位置是否影响准确性。研究方法：参与者（N = 19）在测量的1489米的球场上以自选速度完成了两次步行和骑自行车试验，佩戴两个Garmin GPS装置，佩戴在挂绳和腰带位置。将GPS估计的旅行距离与实际距离进行比较，并检查重测信度。开发了数据清理协议以去除信号噪声。提供了原始数据和清理数据的结果。结果如下：对于原始数据和清理后的数据，在试验（试验1与试验2）、单元放置（挂绳与挂绳）或AT模式（步行与骑自行车）之间没有观察到显著差异（P >= 0.05）。在步行试验中，挂绳和牵引装置均显著高估了行走距离（P = 0.05）。所有试验的原始数据的相对测量技术误差（TEM）范围为3.74%至15.51%，平均绝对误差范围为5.03%至8.53%。对于干净数据，观察到AT模式相互作用的显著位置（P < 0.05）。干净数据的相对TEM范围为1.42%至1.98%，平均绝对误差范围为0.32%至1.97%。使用原始数据和清理数据的所有试验的组内相关性（ICC）均较差至一般。结论：装置初始化期间的信号噪声可能会对装置性能产生不利影响;但是，应用数据清理程序来删除与信号噪声相关的数据可提高装置测量距离的能力。结果表明，挂绳的位置是数据收集过程中的单位的最佳位置。
Purpose: The purpose of this study was to determine test-retest reliability of global positioning system (GPS) units for measuring distance traveled when walking and cycling (AT), and to determine whether GPS unit placement influences accuracy. Methods: Participants (N = 19) completed two walking and cycling trials at self-selected speeds on a measured 1489-m course wearing two Garmin GPS units, worn in lanyard and Waistband placements. GPS estimates of travel distance were compared with actual distance, and test-retest reliability was examined. Data-cleaning protocols were developed to remove signal noise. Results are presented for both raw and cleaned data. Results: For both raw and cleaned data, no significant differences were observed between trials (trial 1 vs trial 2), unit placement (lanyard vs waistband), or AT mode (walk vs cycle) (P >= 0.05). Both lanyard and waistband units significantly overestimated distance traveled during walking trials (P = 0.05). The relative technical error of measurement (TEM) of the raw data ranged from 3.74 to 15.51%, and average absolute errors ranged from 5.03 to 8.53% for all trials. A significant position by AT mode interaction was observed for clean data (P < 0.05). Relative TEM for the clean data ranged from 1.42 to 1.98%, and average absolute errors ranged from 0.32 to 1.97%. Intraclass correlations (ICC) were poor to fair for all trials using raw and cleaned data. Conclusion: Signal noise during unit initialization may adversely affect unit performance; however, application of data-cleaning procedures to remove data associated with signal noise improves unit ability to measure distance. Results suggest that the lanyard position is the optimal placement for units during data collection.