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G. Retscher, T. Hecht, E. Mok:
"Location Capabilities and Performance of Smartphones for LBS Navigation Applications";
Talk: 8th International Symposium on Mobile Mapping Technology, Tainan, Taiwan (invited); 2013-05-01 - 2013-05-03; in: "8th International Symposium on Mobile Mapping Technology", (2013), 6 pages.

In this paper the location capabilities and performance of embedded sensors in modern smartphones in pedestrian and vehicle navigation is investigated. In total, five smartphones were tested in different scenarios for navigation in combined indoor/outdoor environments using GPS and motion sensors such as MEMS-based accelerometers, magnetometer (or digital compass) and gyroscope. In one of the outdoor tests a pedestrian walked repeatedly along a 300 m long trajectory around a residential building block with four- to five-storey buildings. In this test the result of dead reckoning (DR) using the motion sensors is more accurate and reliable than GPS only position fixes as serious obstructions of the GPS satellites resulted in large positioning errors of several tens of metres. Indoor tests were performed in an office building where the user started at a known position and moved to various rooms on the same floor with distances up to 100 m. The user could always be located in the correct room, even most of the time in the correct part of the room. GPS fails in urban canyons or buildings, therefore the use of Wi-Fi fingerprinting was also investigated. The tests in a residential home reveal that around two third of all position fixes are in the correct room and one third yield a false match, e.g. the locations lie in the neighbour room. It could also be seen that there is no significant difference between all smartphones under test. Further tests included a user travelling on public transport in urban canyons. Here the route derived from the dead reckoned motion sensors was again much closer to the real route than GPS only. In all tests it could be proven that the combination of the readily available DR sensors, GPS and Wi-Fi in smartphones can improve the positioning performance in case GPS fails.

Indoor/outdoor positioning, Navigation with smartphones, GPS, MEMS-based sensors, Motion Sensors