We present an algorithm called NoPse (Non Parametric State Estimation) for intelligent fault detection. This is work in progress. The goal was to develop a state estimation system for a rover that would take into account discrete failure modes that produce discontinuities in the behavior of the system. In the rest of the extended abstract we first describe and motivate the problem at hand. Then we present and discuss the algorithm NoPse, and comment on the experimental evidence that is available at present. We conclude by discussing some related work and contrast it with our contributions.