Aiming at the process of transition between high orbit early warning satellites and long range early warning radars in the course of missile defense, two issues were investigated: ballistic error propagation and missile warning information representation. The calculation process of ballistic error propagation using CADET was described. For the results of the error propagation, four kinds of early warning information models, which included the probability ellipsoid model, the probability spherical model, the uniform ellipsoid model, and the uniform sphere model were proposed. The missile warning information of different granularities was calculated using the four models. The simulation results showed that the early warning information models established described the missile state more fully.