Square-root algorithms of RLS Wiener filter and fixed-point smoother in linear discrete stochastic systems

This paper addresses the QR decomposition and UD factorization based square-root algorithms of the recursive least-squares (RLS) Wiener fixed-point smoother and filter. In the RLS Wiener estimators, the Riccati-type difference equations for the auto-variance function of the filtering estimate are in...

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Bibliographic Details
Published in:Applied mathematics and computation Vol. 203; no. 1; pp. 186 - 193
Main Author: Nakamori, S.
Format: Journal Article
Language:English
Published: New York, NY Elsevier Inc 01.09.2008
Elsevier
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ISSN:0096-3003, 1873-5649
Online Access:Get full text
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Summary:This paper addresses the QR decomposition and UD factorization based square-root algorithms of the recursive least-squares (RLS) Wiener fixed-point smoother and filter. In the RLS Wiener estimators, the Riccati-type difference equations for the auto-variance function of the filtering estimate are included. Hence, by the round-off errors, in the case of the small value of the observation noise variance, under a single precision computation, the auto-variance function becomes asymmetric and the estimators tend to be numerically instable. From this viewpoint, in the proposed square-root RLS Wiener estimators, in each stage updating the estimates, the auto-variance function of the filtering estimate is expressed in a symmetric positive semi-definite matrix and the stability of the RLS Wiener estimators is improved. In addition, in the square-root RLS Wiener estimation algorithms, the variance function of the state prediction error is expressed as a symmetric positive semi-definite matrix in terms of the UD factorization method.
ISSN:0096-3003
1873-5649
DOI:10.1016/j.amc.2008.04.026