Estimating Uncertainty of Autonomous Vehicle Systems with Generalized Polynomial Chaos

Modern autonomous vehicle systems use complex perception and control components and must cope with uncertain data received from sensors. To estimate the probability that such vehicles remain in a safe state, developers often resort to time-consuming simulation methods. This paper presents an alternative methodology for analyzing autonomy pipelines in vehicular systems, based on Generalized Polynomial Chaos (GPC). We also present GAS, the first algorithm for creating and using GPC models of complex vehicle systems. GAS replaces complex perception components with a perception model to reduce complexity. Then, it constructs the GPC model and uses it for estimating state distribution and/or probability of entering an unsafe state. We evaluate GAS on five scenarios used in crop management vehicles, self driving cars, and aerial drones - each system uses at least one complex perception or control component. We show that GAS calculates state distributions that closely match those produced by Monte Carlo Simulation, while also providing 2.3x-3.0x speedups.