As announced by Russian Deputy Prime Minister Dmitry Rogozin on May 13, 2014, GPS tracking stations co-sponsored by U.S. interests have stopped making their data available to scientists and others.
The tap on the flow of data from 11 stations was turned off starting on May 31. The data flow included hourly and daily data files from the stations as well as the real-time flow of data over the Internet.
In an item entitled “On Execution of the Instructions of the Government of the Russian Federation,” the website of Roscosmos, the Russian Space Agency, reported:
“In accordance with the instructions of the Government of the Russian Federation, the Russian Space Agency in conjunction with the Federal Agency scientific organizations on June 1, 2014, implemented measures to avoid the use of information from the global seismographic network stations operating on the signals of the GPS system and located in the Russian Federation, for purposes not covered by existing agreements, including military uses.” (As translated by Google Translate.)
It should be pointed out that none of the affected stations contribute to the day-to-day running of GPS; that is, they are not part of the GPS command and control network. They are stations participating in the work of the International GNSS Service, which provides data and products to scientists and other researchers for different purposes including geodesy, geodynamics, orbital mechanics, and atmospheric studies.
It is believed that the Russian move is a tit-for-tat exercise in response to sanctions by western countries following recent events in Ukraine. However, the Russians say that the action was initiated by the refusal of the U.S. to enter into negotiations on the placement of Russian-operated GLONASS tracking stations on U.S. territory. Russia wishes to expand its global network of differential correction and monitoring stations, which could conceivably be also used to supply data for GLONASS command and control purposes.
What isn’t widely known is that Roscosmos already uses sites on U.S. territory for monitoring the availability and health of the GLONASS satellites as the map below clearly shows.