Ezzatallah Faridnia - Young Researchers club, Central Tehran Branch, Islamic Azad University, Tehran, Iran
Mohammad Ali Fariborzi Araghi - Department of Mathematic, Islamic Azad University, Central Tehran branch, P.O.Box 161158131, Tehran, Iran.

in this article, we will describe Quadrature Ensemble Square Root Filter (qEnSRF). The qEnSRF is combined of Quadrature Ensemble Kalman Filter (qEnKF) and Ensemble Square Root Filter (EnSRF). For estimateing and predicting of data in econometric models and in state-space we are going to use Ensemble Kalman Filter. Ensemble Kalman Filter (EnKF) is a method based on assimilation data sequence which is used in a wide range. Then by introducing of the error of Quadrature Ensemble Square Root Filter (qEnSRF) we observe that the error of sampling is reduced significantly

State Space, Data Assimilation, Ensemble Kalman Filter (EnKF), Quadrature Ensemble Square Root Filter (qEnSRF)