1. A method for managing a training arena for training an operator of a host vehicle, the method comprising the procedures of: gathering data by a plurality of native service systems of said host vehicle; generating a training arena data model, the training arena model describing a plurality of virtual entities within said training arena that are managed by a training system, and describing said host vehicle, said training arena model being generated at least according to pre-determined training arena data according to the data gathered by said plurality of native service systems of said host vehicle; for each selected one of said plurality of virtual entities: deriving a portion of said training arena data model that describes said training arena as would have been detected and as could have been perceived from a perspective of said selected virtual entity in case said plurality of virtual entities were real; managing said selected virtual entity for simulating a real entity according to said portion of said training arena data model generating selected virtual entity data describing said selected virtual entity, and updating said training arena model according to said selected virtual entity data; deriving an operator portion of said training arena data model that describes said training arena as would have been detected by said plurality of native service systems of said host vehicle and as could have been perceived by said trainee operator in case said plurality of virtual entities were real, producing a representation of said operator portion; and presenting said representation of said operator portion to said operator; wherein said service systems of said host vehicle including at least one of the list consisting of: radio communication system; helmet system; inertial navigation system; electronic warfare systems; fire control RADAR system; observing system; targeting pod; missile system; and identification friend or foe interrogator.