A Power-Efficient Scheme for Outdoor Localization

With the extensive use of smart phones, location-based services are becoming prevalent. Global Positioning System (GPS) is a widely-adopted localization method. However, it drains the battery of smart phones quickly and it is vulnerable to weak GPS signals. GSM-based localization is more robust, but it only leads to low localization precision, which cannot meet the requirements of many location-based services. With the pervasive deployment of WiFi, WiFi-based localization has become a promising indoor localization method. Nevertheless, simply applying indoor localization methods to outdoor metropolitan environments does not work well. In this paper, we present a hybrid outdoor localization scheme, which leverages WiFi signals and the built-in sensors in smart phones to achieve high localization precision and low power consumption. Our experimental results show that the proposed hybrid scheme outperforms the widely-adopted GPS method in terms of localization precision and power consumption.