基于单轴各向异性完全匹配层边界条件的交替方向隐式有限差分法GPR全波场数值模拟

I-FDTD could break through the restriction of the CFL stability condition and it's unlimited stable. However, UPML boundary condition has the characteristic of absorbing wide frequency and without the necessity for separating electric field from magnetic field. Its simple iterative formula is convenient for compiling program. Synthesized both superiority, this thesis has put forward the GPR numerical simulation algorithm of ADI-FDTD which was based upon UPML boundary condition. Through the discretization of the three two-dimension Maxwell equations, this thesis put forward two sub-time step iterative finite difference formula of ADI-FDTD and UPML boundary condition of GPR wave, and gave the compute steps in detail separately. Based on this, we could compile the responding program, use the program to simulate the two GPR models, get the wiggle maps,scan maps and snapshot of the two models. By analyzed these section maps and snapshot about spreading process of GPR wave, it is known that the regulation of radar wave spreading and changing in the space, so as to guide interpretation of radar data reliably and accurately. The imitate result indicated that the ADI-FDTD algorithm which base on the UPML boundary condition has eliminated the strong reflection of truncating boundaries and it could choose larger time step. So it could imitate GPR model high efficiency, reliably and accurately.