  Kalman Filter (KF) is widely used in various domains to perform sequential
learning or variable estimation. In the context of autonomous vehicles, KF
constitutes the core component of many Advanced Driver Assistance Systems
(ADAS), such as Forward Collision Warning (FCW). It tracks the states
(distance, velocity etc.) of relevant traffic objects based on sensor
measurements. The tracking output of KF is often fed into downstream logic to
produce alerts, which will then be used by human drivers to make driving
decisions in near-collision scenarios. In this paper, we study adversarial
attacks on KF as part of the more complex machine-human hybrid system of
Forward Collision Warning. Our attack goal is to negatively affect human
braking decisions by causing KF to output incorrect state estimations that lead
to false or delayed alerts. We accomplish this by sequentially manipulating
measure ments fed into the KF, and propose a novel Model Predictive Control
(MPC) approach to compute the optimal manipulation. Via experiments conducted
in a simulated driving environment, we show that the attacker is able to
successfully change FCW alert signals through planned manipulation over
measurements prior to the desired target time. These results demonstrate that
our attack can stealthily mislead a distracted human driver and cause vehicle
collisions.
