<FONT face=Verdana>Treatment of error correlation between local estimations is principal part of distributed estimation fusion and track fusion. In view of current situation

in which fusion of multi-sensor hybrid multiple model estimations is still not touched

at first

recursive computation methods for error cross-covariance matrix between local estimations obtained by interactive multiple model estimators whose model set are completely same or partly same is derived. Second

through simulation

the positive definite of cross-covariance matrix is discussed

and its relationship with process noise of maneuver motion model of IMM estimator is investigated. Further

above achievement makes applying Barshalom-Campo algorithm to fusion of IMM estimations as possible

its validity is verified through Monte-Carlo simulation. Compared with other fusion algorithms that ignore error correlation

performance of BC algorithm is more truly.