A professor told me about a project called DORIS http://en.wikipedia.org/wiki/DORIS_%28geodesy%29
In case of a bad accuracy of the „reverse gps“ system, a hybrid system could be used for improving it. For example the backboune of the system is the reverse gps by only single antenna at reception points but at certain reception points 3 antennas can be used for creating a direct position vector pointing to the beacon and limiting the spread of uncertaintiy. Those 3-axis antennas are more likely to be deployed at institues and radio amateurs. And furthermore another step is to allow radio amateurs to directly track the beacon with motorized antennas.