Connected Urban Positioning System in Terrestrial Environment – POUCET

In the field of indoor localization using analysis of radio signals, the scientific publications are based on a initial step to take into account the heterogeneity aspect of this type of environment. The heterogeneity of interior environments composed of open spaces, more or less thick walls, floors and sometimes several levels of basement makes it a complex context to deploy a useful location system. Radio signals are specially distorted in a building and this must be taken into account for an accurate location. The initial step may include fixing reference radio equipments in the building and modeling wave propagation based on building plans or conducting experimental measurements in the building to produce a reference model for radio receptions. In some situations, such as a military mission or a fire, this usual initial calibration step is not possible, because the intervention must be immediate or the use of a radio technology must be inside. An unsolved subject to our knowledge, is the use of a radio system to perform accurate localization without locating radio equipment inside and without calibration step of the received signals in the building . A solution of localization with radio signals to be functional, must rely on a part on possible measurements of distance between transmitters and receivers and other part to be positioned in a space with an absolute reference composed of radio equipment with known coordinates. In the case where the calibration step according to the building can not be carried out and that an initial step in the building is not possible, there are in this case, scientific and technical locks, as the lack of an indoor repository and the lack of an accurate conversion function between a received signal and the distance which are some reasons that do not allow the implementation of existing techniques or solutions.

The consortium project called POUCET (Terrestrial Connected Urban Positioning) will study and explore an interior location solution without an initial step in the building. The analysis of these locks directs us towards a solution composed of an external repository which can be set up immediately and self-calibrated using signals crossing the building and using several systems of indoor measurement. The challenge will be to use and adapt several indoor measurement systems and to merge the acquired data to produce more robust and accurate results. The measurement of the flight time and the attenuation of the radio signals are two methods that will be explored. The exploitation of sound waves is also a possibility, but it has been discarded in this project because it works hard beyond the walls. Finally, the inertial units composed of gyroscopic elements, orientation sensors and sometimes magnetic have the big advantage of being immediately runnable without initialization in a particular building. However, this device can not be implemented alone because it is a location system relating to cumulative error over time. This method is interesting, but it must be associated with solutions of absolute localization to be able to be recalibrated regularly. The challenge of our project is to propose original solutions combining several localization solutions with different operating characteristics.