Variance Analysis of a Cross-Covariance Matching Method for Continuous-Time ARX Parameter Estimation

A method for estimating the parameters of a continuous-time autoregressive exogenous process from discrete-time data is analyzed. The method consists of fitting an expression for the cross-covariance function, parameterized by the unknown parameters, to sample cross-covariances. The main contribution of the note is the derivation of an approximate expression for the covariance matrix of the estimated parameter vector.