In this work, we present a novel robustness measure for continuous-time
stochastic trajectories with respect to Signal Temporal Logic (STL)
specifications. We show the soundness of the measure and develop a monitor for
reasoning about partial trajectories. Using this monitor, we introduce an STL
sampling-based motion planning algorithm for robots under uncertainty. Given a
minimum robustness requirement, this algorithm finds satisfying motion plans;
alternatively, the algorithm also optimizes for the measure. We prove
probabilistic completeness and asymptotic optimality, and demonstrate the
effectiveness of our approach on several case studies