Abstract: Under the condition of active and passive combined multi-base air anti-submarine, the mathematics model for target locating, according to the relationship among the positions of sonar, buoy and submarine is derived. Combined with active sonar equation and passive sonar equation, the positional relationship among target, sonar and buoy, the maximum transmission distance mathematical model of active sonar, the searching and locating scope mathematical models are established. On the base of these mathematical models, simulation results are given to analyze the relationship between the searching scope and the distance of active sonar to buoy, the relationships between the distances of both target to active sonar and target to buoy, the relationships between both buoy position and searching scope and buoy and location scope. Some valuable results are obtained.

Key words: multi-base, air anti-submarine, sonar, buoy, submarine