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dc.contributor.authorSchipperijn, Jen_NZ
dc.contributor.authorKerr, Jen_NZ
dc.contributor.authorDuncan, Sen_NZ
dc.contributor.authorMadsen, Ten_NZ
dc.contributor.authorKlinker, CDen_NZ
dc.contributor.authorTroelsen, Jen_NZ
dc.date.accessioned2021-04-08T03:17:28Z
dc.date.available2021-04-08T03:17:28Z
dc.date.copyright2014en_NZ
dc.identifier.citationFrontiers in Public Health, 2, 21.
dc.identifier.issn2296-2565en_NZ
dc.identifier.urihttp://hdl.handle.net/10292/14102
dc.description.abstractThe emergence of portable global positioning system (GPS) receivers over the last 10 years has provided researchers with a means to objectively assess spatial position in free-living conditions. However, the use of GPS in free-living conditions is not without challenges and the aim of this study was to test the dynamic accuracy of a portable GPS device under real-world environmental conditions, for four modes of transport, and using three data collection intervals. We selected four routes on different bearings, passing through a variation of environmental conditions in the City of Copenhagen, Denmark, to test the dynamic accuracy of the Qstarz BT-Q1000XT GPS device. Each route consisted of a walk, bicycle, and vehicle lane in each direction. The actual width of each walking, cycling, and vehicle lane was digitized as accurately as possible using ultra-high-resolution aerial photographs as background. For each trip, we calculated the percentage that actually fell within the lane polygon, and within the 2.5, 5, and 10 m buffers respectively, as well as the mean and median error in meters. Our results showed that 49.6% of all ≈68,000 GPS points fell within 2.5 m of the expected location, 78.7% fell within 10 m and the median error was 2.9 m. The median error during walking trips was 3.9, 2.0 m for bicycle trips, 1.5 m for bus, and 0.5 m for car. The different area types showed considerable variation in the median error: 0.7 m in open areas, 2.6 m in half-open areas, and 5.2 m in urban canyons. The dynamic spatial accuracy of the tested device is not perfect, but we feel that it is within acceptable limits for larger population studies. Longer recording periods, for a larger population are likely to reduce the potentially negative effects of measurement inaccuracy. Furthermore, special care should be taken when the environment in which the study takes place could compromise the GPS signal.
dc.publisherFrontiers Mediaen_NZ
dc.relation.urihttps://www.frontiersin.org/articles/10.3389/fpubh.2014.00021/full
dc.rights© 2014 Schipperijn, Kerr, Duncan, Madsen, Klinker and Troelsen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
dc.subjectGlobal positioning system; Travel mode; Environmental conditions; Qstarz BT-Q1000XT; Epoch, Validation study; Dynamic accuracy
dc.titleDynamic Accuracy of GPS Receivers for Use in Health Research: A Novel Method to Assess GPS Accuracy in Real-world Settingsen_NZ
dc.typeJournal Article
dc.rights.accessrightsOpenAccessen_NZ
dc.identifier.doi10.3389/fpubh.2014.00021en_NZ
aut.relation.articlenumber21en_NZ
aut.relation.volume2en_NZ
pubs.elements-id163191
aut.relation.journalFrontiers in Public Healthen_NZ


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