This paper is concerned with the distributed fusion estimation problem for discrete-time stochastic linear system with multiple sensors having multiple delayed measurements and correlated noise. Distributed weighted fusion optimal estimators are given based on local optimal estimators from single sensor and the optimal scalar-weighted fusion algorithm in the linear minimum variance sense. Compared with the augmented optimal estimators, the distributed fusion estimators with scalar weights are more reliable and have the reduced computation cost since they have the parallel structure. The estimation error cross-covariance matrices between any two-sensor subsystems are derived. Applying to a tracking system with three sensors shows the effectiveness.
I. INTRODUCTIONtate estimation for time-delay systems has been widely studied due to a lot of applications in signal processing, communication and control systems. The general approaches to design a filter for these systems include the augmented optimal Kalman filter by an augmented state space representation, which brings a high implementation cost, and the optimal filter by directly applying the projection theory [1,2]. When multiple sensors measure the states of the same stochastic system, generally we have two different types of methods to process the measured sensor data. The first method is the centralized filter [3] where all measured sensor data are communicated to a central site for processing. Its advantage is to involve minimal information loss. However, it can result in severe computational overhead. The second method is the distributed filter. Its advantage is that the parallel structures would lead to increase the input data rates and make fault detection and isolation easy. Various distributed filters have been reported for systems without time delays [4][5][6][7] including the federated square-root filter [4], the maximum likelihood fusion filter with assumption of normal distribution [5], the unified fusion rules in weighted least square and best linear unbiased estimate sense [6] and the fusion filter weighted by matrices in the linear minimum variance sense [7]. The Kalman filter for multiple time-delay systems is given by re-organized innovation approach in [8], which involves the computation of multiple filters with the same dimension as the system in series. However, the approach is difficult to be applied when there are possible Manuscript