An analysis of information content of the magnetic gradient field for solution of navigation problems using correlation-extremal method is given on the basis of airborne magnetic data comparison for two surveys performed with more then 10 years interval. An algorithm for the correspondent navigation task solution is proposed in the form of magnetic gradiometer correlation-extremal and inertial navigation systems integration. The algorithm contains the step of a rough estimate of positioning errors by measuring the magnetic field magnitude,the step of more precise trajectory definition taking into account magnetic gradiometer measurements and the step of trajectory maintenance using magnetic gradient reference. The third step is realized as an inertial navigation system correction. Some results of the algorithm test and modeling are given