Indoor positioning system based on inertial MEMS sensors: Design and realization

Nowadays, location-based services (LBS) has become widely used in our daily life. The most famous system is global positioning system (GPS), which is limited to outdoor applications and provide poor locating accuracy. In this paper, we present a positioning systems based on inertial MEMS sensor which includes three-axis accelerometer, three-axis gyroscope and three-axis magnetometer. The system can help people get accurate positioning for indoor environments, also available for outdoors, because of its self-contained character. It is a foot wearable device with wireless network to transmit movement information to computer that can calculate the relative position and show the path walked by. The key concept of the positioning system is inertial navigation and dead reckoning technology. Since it needs twice-integration of the acceleration to get the position, the displacement will drift by time elapse. We make it only drift by distance increasing through gait phase analysis, a method called Zero-Velocity Update (ZVU). As the “stand-still phase” is the key of the system performance, we mainly focus on getting accurate gait phase detection. We used decision tree here and the experimental results showed that we got a gait phase detection accuracy of 99.96% and positioning accuracy of 97.37%.