Improper usage of UAV or drone allows people to conduct strikes on vital properties, such as a military base. The critical capabilities of drone are its movement flexibility and its relatively small size. These abilities make standard radar systems hard to detect drone position. Thus, the counter-attack maneuver towards drone attacks becomes difficult. We propose a framework to establish a radar-like information system that can track the location of any intruder drone attacking a prohibited area. It works by using a UAV tracker equipped with a calibrated 2D camera and GPS sensor. This tracker uses a camera to detect the existence of an intruder, then follow the intruder while sending the intruder's coordinate to a specific server by estimating the intruders' location using both sensors. We describe the mathematical model to estimate the relative position of an intruder drone from our UAV tracker by using a 2D camera, then combine the obtained information with GPS sensor data to pinpoint the coordinate of any intruder. We adopt the Area Expansion Principle as the mathematical model. As a result, we reduce the cost of intruder drone detector system that is useful for defending an area.