Which satellite was the first navigation satellite in the world?

1On April 3, 1960, the United States launched the world's first navigation satellite "meridian instrument".1July, 1964, a navigation satellite network was officially put into use. Meridian is the first generation navigation satellite system in the United States. It consists of six satellites. It has the advantages of all-weather, global navigation and positioning of a single satellite. Two-dimensional positioning can be carried out, and the positioning accuracy is 20 ~ 400 meters.