To estimate launching position and hitting position of a bullet accurately by providing four systems or more of circuit for receiving a sound wave through an acoustic sensor when a bullet is launched and exploded and measuring the rising time of the sound wave and estimating the position of a sound source three-dimensionally or two-dimensionally utilizing the arriving time difference of sound wave between respective systems.

Sensor sections 1-4 each comprising a temperature sensor, an acoustic sensor, a GPS and a wind direction anemometer are disposed at four points and measured data is converted into RF band before being transmitted to a common signal processing section. The signal processing section receives the launching, flying and exploding sound of a bullet and corrects refraction of the sound wave due to the temperature of the sound wave propagation passage and wind. Launching position, flying passage, hitting point, exploding altitude and type of the bullet are estimated utilizing the map data in the vicinity of launching and hitting positions of bullet, time difference of the launching sound of bullet arriving at respective sensors, variation of Doppler frequency contained in the flying sound of bullet, and time difference of the exploding sound of bullet arriving at respective sensors.