1. Method for determining protection limits at a future moment associated with navigation states of a carrier comprising: measuring data on navigation states of the carrier through sensors of the carrier; based on said measured data, estimating, with an estimating filter, navigation states of the carrier at the present moment, producing a statistical model of estimation errors of navigation states of the carrier at the present moment in the form of a covariance matrix, extrapolating the statistical model of estimation errors to a future moment, wherein said extrapolating comprising a multiplication of: a transition matrix, with constant and positive coefficients, with a standard deviation vector constructed from the square roots of the elements of the diagonal of the covariance matrix of the estimating filter, in order to propagate standard deviations of the navigation states produced at the present moment, to a future moment, the propagation of standard deviations of navigation states being independent from previous dynamics of the carrier, and calculating a protection limit at the future moment using the extrapolated statistical model.