The paper presents consideration of the solution of the nonlinear inverse problem of gravity exploration in the grid class of field sources if there are anomalies in the section that have positive and negative effective densities. In this case, practical equivalence is very strong and the reliability of the results of quantitative interpretation decreases. Based on the assembly method the author consideres the possibility of decomposing the inverse problem into two separate computational procedures. It is implemented using pre-separation of the gravitational field into components caused by objects with different effective densities. The author used a system of equivalent sources that were successively plunged to a depth approximating the in...