The Fast Collection of Radio Fingerprint for WiFi-Based Indoor Positioning System

Mobile communications and Internet have become one of the most important services nowadays. Most mobile devices, such as cell phone, PDA, and laptop computer, equipped with the WiFi, GPS, and Bluetooth as their standard equipment, and people have got used to use mobile services in their daily life. One interesting service is Wifi-based indoor positioning system (IPS) that attracts many researchers devote their effort to it. Many researches in IPS determines the user location by the method of scene analysis. However, this method need to collect the AP’s RSSI in many places in the building (called sample points) beforehand to build a WiFi radio fingerprint database, which is a time-consuming work. Meanwhile, it also needs resampling very often in order to keep the accuracy of the positioning result. In this paper, we design and test a fast setup algorithm for collecting those sampling information. The Android smartphone and its build-in motion sensors were used to help to collect the AP’s RSSI. We use the motion sensor to determine the steps while walking and collect the AP’s RSSI in every step. The method completes the sampling work in a walking period which much shorten the time for sampling. This paper also compares the fast setup method with the traditional method from the positioning accuracy point of view. Experiments show that there is no significant difference between them.