 In fact, the elevation of Mount Everest was corrected in the late 1980s by using a Transit receiver to re-survey a nearby benchmark.Thousands of warships, freighters and private watercraft used Transit from 1967 until 1991.In the 1970s, the Soviet Union started launching their own satellite navigation system "Parus" (military) / Tsikada (civilian), which is still in use today besides the next generation GLONASS.