Airport multipath simulation for siting DGPS reference stations

Christophe Macabiau (1) , Benoit Roturier (1) , Eric Chatre (2) , Alain Renard (3)

1 ENAC - Ecole Nationale de l'Aviation Civile
2 DGAC - Direction Générale de l'Aviation Civile
3 SEXTANT Avionique

The siting of a GPS reference station on an airport is achieved by minimizing the influence of the environ-ment on the pseudorange measurements, while comply-ing with the practical operational installation constraints. The CNS Research Laboratory (URE-CNS) of the ENAC, in collaboration with the STNA and SEXTANT AVION-IQUE, has started a study that aims at providing siting guidelines for the French Civil Aviation Authority. As a result, a tool is developed, based on computed error predictions using mathematical models, and on signal disturbance measurements at preselected locations. The first part of this tool is an end-to-end GPS simulator that is used to establish the main basic rules for the choice of the best location of the station on an airport with regards to multipatb effects. Its goal is to analyse the measure-ment errors induced by simple obstacles. The aim of the proposed paper is to present the sim-ulation software which was developed and some exam-ples of the results it can provide. The simulator is comprised of three cascaded mod-ules. The first module computes the position of the satel-lites with a time step larger than the time of coherence of the propagation channel. The second module simu-lates the propagation channel. It is derived from the ray-tracing MUSICA tool (MUltipatb Simulation for Civil Aviation) that was previously developed by the ENAC for classical navaids multipath simulation. Using the channel transfer function determined through the Uni-form Theory pof Diffraction, it generates the disturbed signal delivered by the antenna of the station to its re-ceiver front-end. Then, this signal is handed to the last module, that simulates a generic GPS receiver and de-livers the range measurement errors induced by the per-turbations introduced in the whole propagation channel. The examples chosen show the ability to predict the in-fluence of reflecting and diffracting objects, such as the ground and buildings on the code and phase measure-ment errors.

Domaines: Traitement du signal et de l'image [eess.SP]; Traitement du signal et de l'image [eess.SP]

Christophe Macabiau, Benoit Roturier, Eric Chatre, Alain Renard. Airport multipath simulation for siting DGPS reference stations. ION NTM 1999, National Technical Meeting of The Institute of Navigation, Jan 1999, San Diego, United States. pp 135 - 144. ⟨hal-01021686⟩