Inverse scattering problem for moving obstacles (Q1177425)

Scattering by a moving obstacle is considered under the following assumptions: 1) The obstacle remains inside a fixed ball; 2) its boundary has a speed less than one; and 3) for large \(| t|\) the obstacle is at rest, where \(t\) is time. It is also assumed that the Dirichlet boundary condition holds (the wave field vanishes at the boundary). It is proved that the scattering kernel defines the obstacle uniquely, and if condition 3) is dropped, uniqueness fails, in general.