The mathematical models of inverse trajectory problems of the form “state – measurement” are presented. The aim and main component of the solutions is to estimate the surface sea current velocity vector after reconstructing the absolute (relatively solid Earth) velocity of the object according to its positioning GLONASS data. These models are associated with the model of estimating problem the derivatives of a continuous time function with respect to its temporally measurable values having the Jordan form of a matrix with a nilpotency index. It coincides with the dimension of the system of linear differential equations of state, which causes discretization of the problem in time without methodological errors and the implementation of computational algorithms for dynamic handling Using the ordinary Least Squares method with a sliding window. The peculiarity of this solution methodology is that it identifies the flow with the portable movement of a controlled marine object, considers it as a navigational factor that changes in time and geographical space and requires on-board operational assessment of the current state. The results of computational experiments are also presented.