Indoor navigation and modeling using photographed evacuation plans and MEMS IMU

In this paper, we present an approach for the model ing of building interiors by a user who is equipped with a navigation system, which integrates MEMS IMU data processing with automatic interpretation of photos of evacuation plans. Such emergency plans for the evacuation of buildings are compulsory for public b uildings in a number of countries. They consist of an approximate floor plan, the current position and escape routes. Additionally, s emantic information like stairs, elevators or the l evel number may be found. If an image of such a floor plan is captured by a potenti al user, this information is made explicit again by a suitable raster-to-vectorconversion. The resulting approximate indoor buildi ng model can then refined by semi-automatic data co llection. Similar to outdoor scenarios like OpenStreetMap, features of interest can be collected interactively while the user moves through the building. By these means the entrances of rooms, positions of windows, facilities etc can be integrated into the availabl e indoor model. However, this presumes a suitable positional accuracy during indo or navigation. This is realized using inertial meas urements from a low-cost MEMS IMU. Their evaluation by a ZUPT-(zero velocity upda te)-based algorithm is further supported by integra ting information from the evacuation plan like the initial position of the us er at the location of the plan. Furthermore, typica l constraints for indoor environments like detected stairs or an assumed movement paralle l to outer walls are applied to eliminate drift eff ects of the used low-cost sensor system. This provides a suitable accuracy to allow for an efficient map refinement.