Usability of apple iPhones for inertial navigation systems

In recent decades, many indoor positioning techniques have been researched and some approaches have even been developed into consumer products. Most of them have been deployed into companies which benefit from indoor asset tracking. However, for public buildings like libraries or transportation systems, no direct benefit exists by installing expensive systems. Inertial navigation systems offer a form of positioning which is almost completely independent from external infrastructures, inexpensive and privacy friendly. As prices for sensors continuously drop, mobile terminals, such as cell phones or tablet PCs, are being equipped with various additional components, like GPS, cameras and light sensors, and moreover gyroscopes, compasses and accelerometers integration is also becoming commonplace. These last three components enable inertial navigation systems to calculate the position of the device. In this paper, we selected two devices, the iPhone 3GS and the iPhone 4, to analyze their sensors for usability of an inertial navigation system. For each device a common strapdown algorithm was implemented and varying standard filters applied to clean the output data stream of the sensors. Finally, we present the results, which are diverse according to the devices.