Unscented Kalman Filter

The Unscented Kalman Filter (UKF) is a nonlinear state estimation algorithm that approximates nonlinear systems without requiring explicit Jacobian computation. Introduced by Julier and Uhlmann in 1997, the UKF uses the unscented transform—a deterministic method to capture mean and covariance statistics through a carefully chosen set of sample points (sigma points)—making it more accurate than the Extended Kalman Filter for highly nonlinear systems while avoiding the computational burden of derivative calculations.