With the smartphone boom, positioning oneself on the Earth's surface has become something common. Everyone know how to uses their smartphone to get their location or finding their way. However, achieve centimetric accuracy on positioning still a topical issue that arouses considerable interest. Geodetic GNSS antennas are currently used for this field, but their price is incompatible with the mass market applications (autonomous cars, drones, machine automation, photogrammetry, etc.). In this paper, an approach to improve the Android smartphone positioning is presented using low-cost GNSS receiver. Requested by Syslor, a start-up working in buried networks, the society want to enhance its customer services. The purpose of this study is to present a method to reach centimetric localisation of smartphones for augmented reality and as-built 3D plans applications.