Rapid expansion in air traffic volume and demand will create substantial challenges for Air Traffic Management (ATM) system over the coming decades. By 2015, air traffic is expected to climb by 25-30% overall on average and even higher in certain areas of the country. Automatic dependent surveillance- broadcast (ADS-B) is a cooperative surveillance technique for air traffic control which has been approved by the FAA. With its increasing usage and popularity, an airborne radar system using ADS-B system was introduced in 2008. In this paper, the authors propose a technique for multiple target estimation and tracking in order to overcome the constraints of ADS-B radar system. This system can greatly reduce the necessity of communication between aircraft and air traffic control (ATC) and flight safety will be further secured. Computer simulation results show that the proposed method effectively performs multiple target estimation and tracking for ADS-B radar system.