The Russian positioning system GLONASS has placed ground stations in Brazil and Nicaragua; the different accessibility of them to nationals gives rise to conjectures
At a time when Russia has declared its interest in having new military facilities in the Caribbean, the opening of a Russian station in the Managua area has raised some suspicions. Roscosmos, the Russian space agency, has opened four stations in Brazil, managed with transparency and easy access; instead, the one that has built in Nicaragua is surrounded by secrecy. What little is known about the Nicaraguan station, strangely greater than the others, contrasts with the openly that data can be collected on the Brazilians.
ARTICLE / Jakub Hodek [Spanish version]
We know that information is power. The more information you have and manage, the more power you enjoy. This approach must be taken into account when examining the ground stations that serve to support the Russian satellite navigation system and its construction in relative proximity to the United States. Of course we are no longer in the Cold War period, but some of the traumas of those old times may help us to better understand the cautious position of the United States and the importance that Russia sees in having its facilities in Brazil and especially in Nicaragua.
That historical background of the Cold War is at the origin of the two largest navigation systems we use today. The United States launched the Global Positioning System (GPS) project in the year 1973, and possibly in response, the Soviet Union presented its own positioning System (GLONASS) three years later.  It has been almost 45 years, and these two systems no longer serve Russians and Americans to try to get information on each other, but are collaborating and thus offering a more accurate and fast navigation system for consumers who buy a Smartphone or other electronic device. 
However, in order to achieve global coverage, both systems need not only satellites, but also ground stations strategically distributed around the world. For that purpose, the Russian Federal Space Agency, Roscosmos has erected stations for the GLONASS system in Russia, Antarctica and South Africa, as well as in the Western Hemisphere: it has four stations in Brazil and since April 2017 has one in Nicaragua, which by secrecy around its purpose has caused mistrust and suspicion in the United States  (USA, for its part, has ground stations for GPS in its territory and Australia, Argentina, United Kingdom, Bahrain, Ecuador, South Korea, Tahiti, South Africa and New Zealand).
The Russian Global Satellite Navigation System (Globalnaya Navigatsionnaya Sputnikovaya sistema or GLONASS) is a positioning system operated by the Russian Aerospace Defence Forces. It consists of 28 satellites, allowing real-time positioning and speed data for the surface, sea and airborne objects around the world.  In principle GLONASS does not transmit any personally identifiable information; in fact, user devices only receive signals from satellites, without transmitting anything back. However, it was originally developed with military applications in mind and carries encrypted signals that are supposed to provide higher resolutions to authorized military users (same as the US GPS). 
In Brazil, there are four Earth stations that are used to track signals from the GLONASS constellation. These stations serve as correction points in the Western hemisphere and help significantly improve the accuracy of navigational signals. Russia is in close and transparent collaboration with the Brazilian Space Agency (AEB), promoting research and development of the aerospace sector of this South American country. In 2013 the first station was installed, located on the campus of the University of Brasilia, which was also the first Russian station of that type abroad. It followed another station in the same place in 2014, and later, in 2016, a third was put in the Federal Institute of Sciences of the education and technology of Pernambuco, in Recife. The Russian Federal Space agency Roscosmos built its fourth Brazilian station on the territory of the Federal University of Santa Maria, in Rio Grande del Sur. In addition to fulfilling its main purpose of increasing accuracy and improving the performance of GLONASS, the facilities can be used by Brazilian scientists to carry out other types of scientific research. 
The level of transparency that surrounded the construction and then has prevailed in the management of the stations in Brazil is definitely not the same as the one applied in Managua, the capital of Nicaragua. There are several information that create doubts regarding the true use of the station. For starters, there is no information about the cost of the facilities or about the specialization of the staff. The fact that the station has been put at a short distance from the U.S. Embassy has given rise to conjecture about its use for phone-tapping and spying.
In addition, the vague replies from the representatives of Nicaragua and Roscosmos about the use of the station, have not managed to transmit confidence in the project. It is a "strategic project" for both Nicaragua and Russia, concluded Laureano Ortega, the son of the Nicaraguan president. Both countries claim to have very fluid and close cooperation in many areas, such as in health and development projects. However, none of those collaborations have materialized with such speed and dedication as this particular project. 
Given Russia's larger military presence in Nicaragua, empowered by the agreement that facilitates the mooring of Russian warships in Nicaragua announced by Russian Defense Minister Sergei Shoigu during his visit to the Central American country in February 2015, and specified also in the donation of 50 T-72B1 Russian tanks in 2016 and the increased movement of the Russian military personnel, it can be concluded that Russia clearly sees strategic importance in its presence in Nicaragua.   This is all observed with suspicion from America. The head of South American Command, Kirt Tidd, warned in April that "the Russians are moving forward a disturbing attitude" in Nicaragua, which "impacts the stability of the region."
Without a doubt, when world powers like Russia or the United States act outside their territory, they are always guided by a combination of motivations. Strategic positioning is essential in the game of world politics. For this very reason, the aid that a country receives or the collaboration it can establish with a great power is often subject to political conditionality.
In this case, it is difficult to know for sure what is the purpose of the station in Nicaragua or even those of Brazil. At first glance, the objective seems neutral – offering higher quality navigation system and providing a different option to GPS –, but given the new importance that Russia is granting to its geopolitical capabilities, there is the possibility of more strategic use.