This contribution investigates how accurate location information is on smartphones. Our research is based on a data set consisting of 2289 locations gathered from a marketed iPhone application. In a first analysis, it became evident that the accuracy information differs significantly among iPhone and iPod and iPad devices. A second analysis of the accuracy values reveals clusters of accuracy values at above 1 km, at 500 meters, and at an accuracy of below 300 meters. Information with an accuracy of above 500 meters originated from Cell-ID based positioning. Finally, an analysis revealed that the accuracy is significantly reduced for locations with more than 500 meters away from the next populated area. The overall results suggest that additional Cell-ID based positioning technology allows for higher coverage at the costs of a significantly reduced accuracy. If location information is required, with an accuracy of below 300 meters, the technology should be limited to GPS and WLAN based positioning. Adding Cell-ID based positioning increases the coverage while accuracy is reduced.

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Information about health, disease or environmental conditions is increasingly becoming available. We investigate the suitability of using mobile phones as an interface to provide information about risk-related events or conditions to the user. We approach the problem by conducting an online survey in order to match the requirements on a risk information service with the capabilities of the mobile phone and to evaluate different notification mechanisms, the usage frequency, and the influence of costs. Based on the results of the survey we confirm the suitability of the mobile phone to provide risk-related information as well as the user's willingness to pay for the service.

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