IEEE Transactions on Automatic Control, Vol.65, No.3, 1089-1099, 2020
On the Well-Posedness of a Parametric Spectral Estimation Problem and Its Numerical Solution
This paper concerns a spectral estimation problem in which we want to find a spectral density function that is consistent with estimated second-order statistics. It is an inverse problem admitting multiple solutions, and selection of a solution can be based on prior functions. We show that the problem is well-posed when formulated in a parametric fashion, and that the solution parameter depends continuously on the prior function. In this way, we are able to obtain a smooth parametrization of admissible spectral densities. Based on this result, the problem is reparametrized via a bijective change of variables out of a numerical consideration, and then a continuation method is used to compute the unique solution parameter. Numerical aspects, such as convergence of the proposed algorithm and certain computational procedures are addressed. A simple example is provided to show the effectiveness of the algorithm.
Keywords:Covariance matrices;Optimization;Estimation;Convergence;Density functional theory;Inverse problems;Feeds;Generalized moment problem;numerical continuation method;parametric spectral estimation;spectral factorization;well-posedness