Navigation System Simulation in Support of Application Development

Abstract

The paper presents this approach in depth and provides results obtained in the domain of traffic management. During a test campaign, an urban canyon scenario was addressed. By means of a GPS receiver, trajectory data was measured and used as the reference for the subsequent simulation. For each measured position over time along the trajectory, the observables were produced for both GPS and Galileo. This simulated data was used to compute the positioning solution. A direct comparison between the measurements and the simulated GPS positioning demonstrates an adequate level of model representation. Detailed analyses of GPS and simulated Galileo performance have shown the impact of the restricted availability of navigation satellites through the shading of the signals by the buildings. As expected, best results are achieved if GPS and Galileo are used jointly. Here, the number of satellites visible to the receiver increases leading to on improved positioning solution. In reality, also reflected signals contribute to the positioning solution causing significant errors. This was analysed by means of the GPS measurements, where positioning errors up to 50 m were identified due to multipath effects. In these cases alternative navigation systems such as inertial navigation systems become necessary.