Method and system for estimating state variables of a moving object with modular sensor fusion

A computer-implemented method is provided for estimating state variables of a moving object, which includes: propagating core state variables of the moving object utilizing a recursive Bayesian filter and observation values from sensors from start-up of the moving object; forming, utilizing observation values from one or more additional sensors added after start-up, a covariance matrix of the recursive Bayesian filter; updating the covariance matrix based on observation values formed by at least one additional sensor; and, ascertaining the covariance of the core state variables of the additional sensor at a time after start-up.