A study on the accuracy of GPS positioning during jamming

In this study we investigate the influence of radio frequency interference on 95% confidence ellipses for positioning using a low-cost GPS receiver. The study has been performed with an experimental set-up where a jammer influences a software defined receiver at several distances in an open field. Post-processing the measurements showed that for certain distances the receiver was unable to receive the signals of some satellites with the jammer active. As a result the confidence ellipses enlarged in these situations. Furthermore it was observed that size of the confidence regions depend heavily on the geometry of the satellites, whose signals could be received in the measurements. Results of the study will be used for building GPS jamming scenarios into ship handling simulators to prepare bridge crews for such situations.