This paper describes state estimation techniques for multilevel multisensor surveillance systems.Based on the single sensor Kalman filtering equations

two level centralized and distributed estimation solutions

this paper presents the three level centralized estimation algorithms for hierarchical multisensor tracking systems in multicoordinates systems.In the difference Cartesian coordinates

several kinds of track level fusion methods for three level multisensor data fusion sytems are proposed

in which both centralized distributed amd distributed distributed estimation combination problems are considered.It is shown that the opimality can be guaranteed under some communication requirements from the fusion center to the local nodes or the local nodes to the sensors.In addition

the austere solutions for hierarchical estimates in multilevel multisensor systems are given.