This use has been the formation of trajectory, using three steps the starting point for numerical integral method of extrapolation of the projectile. First two integrals to determine trajectory prediction parameters, ensure accuracy trajectory extrapolation and use of integral parameters of numerical integration for the third time to obtain the starting position of the projectile. The integral interval from the end point of the trajectory filtering is the third integral to the muzzle.The integral result of the conversion to a radar plane coordinates.Can effectively ensure the accuracy of trajectory and accurately obtain the projectile firing position,applies to weapon location radar trajectory prediction of mortars and howitzers muzzle.