1. A computer-implemented sonic boom prediction method for use in designing a supersonic aircraft, comprising: receiving physical parameters and performance parameters for a supersonic aircraft; generating a three-dimensional (3D) flow field around the supersonic aircraft for at least one airspeed and at least one flight altitude using a CFD model in a first region of a near field bounded by a first radial distance and a propagation model in a second region of the near field bounded by the first radial distance and a second radial distance, wherein the 3D flow field generated by the CFD model is used as a boundary condition for the propagation model; estimating sonic boom signatures on a ground surface using a long distance sonic boom propagation model that incorporates the 3D flow field estimated by the propagation model as an initial condition; and adjusting parameters of the supersonic aircraft to reduce estimated sonic boom signatures.