Evaluating the performance of low cost MEMS inertial sensors for seamless indoor/outdoor navigation

For all mobile, location based applications, location availability (either on demand or continuously) is the primary performance requirement of the positioning technologies used. In most cases, this requirement outweighs that of meeting a specified accuracy, as the granularity of information provided to the user can be scaled around the computed positioning accuracy. What is therefore important is being able to generate a position solution and its accuracy at a specified level of confidence. For these applications, meeting the requirement of 100% availability is a significant challenge for individual positioning technologies, even more so when navigating between indoor and outdoor environments. Whilst operating under ideal operating conditions, GPS provides excellent positioning coverage. In indoor environments, position solutions can be generated using infrastructure based technologies such as RFiD and WiFi or augmentation sensors such as inertial navigation systems. Micro- Electromechanical Sensor (MEMS) inertial sensors are a popular option as they offer an autonomous capability that can potentially augment performance seamlessly across indoor and outdoor environments with marginal cost implications. This paper presents the results of a practical test undertaken to evaluate the performance of commercially available MEMS inertial sensors. In particular, results obtained that characterize the performance of these sensors against GPS in the transition zone between indoor and outdoor environments will be presented.