A comparative analysis of GNSS functional augments' current state compliance with possible requirements of users as to the navigational support’s precision is made. The structure of perspective wide-zone high precision complex for functional augmenting is offered. It is to satisfy the users’ possible future requirements. The results of researching the complex’s working algorithms are shown; the system of differential correction and monitoring was used. Basing upon the results the conclusions on the prospects of developing the high-precision positioning systems are made.