The modern achievements in the construction of small flying machines cause the active development of remote monitoring, in particular geophysical airborne gamma-ray spectrometer surveying. Such observations are important, since large amounts of man-made radioactive materials get into the environment, especially during accidents like at the Chornobyl or Fukushima nuclear plants. On the other hand, the natural distribution of radioactive sources is inhomogeneous and can provide us with useful information about the soil structure. One of the problems appearing at the handle of information collected with unmanned aerial vehicles concerns the correction of readings to identify the peculiarities of gamma-ray fields. To perform this, the analytical method based on the solution of the inverse problem formulated in terms of integral relation is used. In this research, to reconstruct the surface distribution of the gamma-ray field, the Tikhonov and Landweber techniques are applied. It is shown that these algorithms allow one to distinguish radioactive hot-spots located closely.