Electromagnetic Theory of Range-Doppler Imaging in Laser Radar. 1. ScatteringTheory

摘要

An electromagnetic theory of range-Doppler image formation is presented. The newformalism replaces scattering from the diffusely reflecting surface of a moving target by scattering from N noninteracting, classical atoms uniformly distributed over the visible surface of the original target. The total field scattered by the collection of moving atoms is then calculated with the use of the Lienard-Wiechert field formalism. It is demonstrated that the new theory, by comparison with currently available scalar theories, gives a much more accurate description of the important features of the image-formation process. In particular, the new theory takes into account diffraction of the transmitter beam and movement of the target during illumination and is capable of describing wave-front aberration and the bistatic Doppler shift. It also permits the simulation of the time dependence of (Gaussian) speckle in the receiver aperture plane. Because of the simplicity of the scattering model, the theory cannot account for depolarization of the radiation scattered by real surfaces.