Ground-penetrating radar:: Postmigration stacking of n-fold common midpoint profile data

Diffraction and nonvertical side-looking reflection patterns are typical features of most commercial ground-penetrating radar (GPR) surveys. While a number of techniques are used by GPR workers to migrate such signals back to the proper position of the subsurface reflector, these have not been generally applied to multifold data nor to conditions of extreme noise. A procedure known among seismologists as wavefront migration is adapted here for processing multifold common midpoint (CMP) GPR data; it appears to be promising for both noise-free and noisy data. The algorithm is largely geometrical and nonmathematical, and it is readily implemented on a personal computer. An example of synthetic data with extreme levels of noise illustrates that migrating prestack multifold CMP data, followed by postmigration, n-fold stacking, leads to a substantial improvement in image quality over unmigrated or single-fold migrated data.