Russia has launched three satellites to extend its version of the U.S. Global Positioning System to the entire Russian territory.

The satellites were sent into orbit on a Proton-M rocket that blasted off last week from Kazakhstan, said Alexander Vorobyov, spokesman for Russia’s Federal Space Agency. They are to join Russia’s Global Navigation Satellite System, or GLONASS.

The system, which serves both military and civilian purposes, was developed during Soviet times and was supposed to have 24 satellites. Their number dwindled after the 1991 Soviet collapse, but the Russian government is trying to revive it by earmarking funds from windfall oil revenues.

First Deputy Prime Minister Sergei Ivanov said last week’s launch would bring the GLONASS satellite fleet to 18 – the number necessary to provide navigation services over the entire Russian territory.