For GNSS systems, the gain, phase and group-delay patterns of the receiver antenna have an impact on the pseudo-ranges, i.e. the apparent distances to the satellites estimated by the receiver. In the presence of multipath, this impact is difficult to assess because multipath and antenna effects are mixed. In this article, these sources of pseudo-range error are analyzed by means of simulations for an aircraft moving at the surface of an airport. For the simulations, we rely on a hybrid statistical-deterministic GNSS multipath simulator combined with a receiver simulator. Various antenna models are tested, e.g. an ideal isotropic antenna and a realistic antenna mounted on an aircraft, with and without the phase and group-delay patterns.