Two-level form of the Kalman filter

Sequential estimation of the states of several high-order interconnected systems may be prohibitive on computer time and storage if the problem is formulated as for a single system. Therefore, multilevel systems theory has been applied to derive a coordination algorithm, with one-step convergence, for a number of subsystem Kalman estimators. The procedure may be computationally attractive for sparsely coupled subsystems with few stochastic inputs.