GIMPhI: A novel vision-based navigation approach for low cost MMS

Over the last two years, the Geomatics research group at the Politecnico di Torino has developed a Low Cost System, in which only low cost sensors are involved. The system is equipped with webcams, an MEMS IMU and up to four GNSS receivers. During this development, several (non negligible) problems have been solved in order to obtain good quality after the data processing. One of the main problems of the low cost systems concerns the occurrence of GNSS outages. In this case, the IMU can only estimate the trajectory and the attitude of the vehicle for short periods. For this reason, considering the high number of frames available (about 3–5 frame per second, fps), a vision-based navigation (VBN) approach, called GIMPhI (GNSS IMU and PHotogrammetry Integration), has been adopted and tested. The navigation solutions have been refined by means of integration with a photogrammetric approach (bundle block adjustment) and a rigorous weight matrix has been adopted in order to consider the different accuracies of the various sensor observations (GNSS, IMU and images). A detailed description of this integrated approach is presented in this paper. The first tests and the achieved results are then shown in order to evaluate the reliability of the proposed approach.