Abstract: Compared with traditional methods, the target selection method, which makes use of the shape of a ship formation (SSF) and is therefore named an SSF method, has better ability to select the target ship. To check the applicability of SSF method, the ability of the air-to-ship missile (ASM) to acquire SSF is studied. First, a model of the minimal search angle in the azimuth of the terminal guidance radar (TGR) is deduced. Given a launch distance of the ASM, the appropriate search angle is computed based on the model. If the appropriate search angle is utilized to search objects, the probability to record all the objects in the ship formation, i. e., the record probability by the TGR, will be up to 1; in addition, it may reduce the chance of the TGR to be disturbed. Next, the expression of the probability to distinguish each object in the ship formation, i. e., the distinguishing probability, is deduced. Then the probability to acquire perfect SSF equals to multiplying the record probabilities of airborne fire-control radar (AFCR) and TGR by their distinguishing probabilities. Thirdly, the origin of the distortion is studied, and the probability expression to correctly select the designated target conditioned by a perfect SSF is deduced. This probability reflects how the distortion of the SSF influences the performance to select the designated target. Finally, the probability to correctly select the designated target when perfect SSFs are acquired is utilized to describe the ability of the ASM weapon system (referring to the AFCR and TGR) to acquire the SSF. Computation results show the probability to correctly select the designated target is more than 0.547 8 when the launch distance of the ASM is less than 322.3 km, which indicates the SSF method is applicable to ASM.

Key words: missiles, airborne fire-control radar, terminal guidance radar, ship formation, shape matching