The World Health Organization assesses the number of visually impaired people to be nearly 285 million in August 2014, of whom 39 million are blind. One of the most important discomfort factors for these persons is known to be the difficulty in moving and orienting by themselves in unfamiliar surroundings. Nowadays, several devices are currently available for supporting these persons in there everyday life. To this end, the attention in this paper is mainly focused on the localization and navigation in indoor environment. The solution adopted in this paper consists in populating a database of virtual maps, that the user itself contributes to create by exploring the surrounding environment. An inertial platform, represented by a set of sensors (basically accelerometer, gyroscope, electronic compass) placed in a device worn by user, is used at the purpose as sensing system. This approach does not require the installation of external equipments since it relies on a smartphone, which is used both as measurement platform and user interface, and, in particular, does not require any a-priori knowledge of the indoor environment. The application will be described in the paper where some experimental preliminary results will also be discussed.