Present and future marine navigation requirements have been analysed recently for different categories of users. This paper relates to those navigation applications which need very high real-time accuracy, high availability and reliability of navigation information. This domain is mainly influenced by marine surveying and navigation community needs such as oil and mineral prospecting, hydrography and future prospecting of maritime economic zones, which are usually of high strategic or economic importance. The majority of identified needs for this limited community of users call for real-time accuracy and repeatability of instantaneous positioning ranging from 2 to 10 m, distances from shore up to 1500 km (water depth 300–1000 m), update rate of position information of a few seconds, and availability and reliability of position information data of 99 per cent or more. To reach such stringent requirements none of the existing means and even new satellites or Earth-based acoustic or radio aids individually can solve the problem. This leads to the necessity of combination or hybridization of several means which together may approach the solution.