How many satellites are there in gps?

GPS is the second generation satellite navigation system in America. It is developed on the basis of meridian satellite navigation system and absorbs the successful experience of meridian system. According to the planning scheme, the space part of GPS uses 24 satellites with a height of about 20,200 kilometers to form a satellite constellation. The distribution of satellites makes it possible to observe more than four satellites anywhere in the world at any time and maintain a geometric figure with good positioning accuracy.

Since the advent of GPS, it has attracted many users with its high precision, all-weather, global coverage, convenience and flexibility. GPS is not only the patron saint of automobiles, but also the intellectual star of logistics industry management. With the rapid development of logistics industry, GPS plays an important role and becomes the second largest consumer group after the automobile market.

GPS historical background

GPS refers to a radio navigation and positioning system that uses GPS satellites to provide three-dimensional position, three-dimensional speed and other information in real time around the world. The predecessor of GPS is the transit satellite positioning system developed by the US military in 1958, which was put into use in 1964. The system works in a star network consisting of 5~6 satellites, and it orbits the earth 13 times at most every day, so it can't give altitude information, and its positioning accuracy is not satisfactory.

However, the meridian satellite positioning system has enabled R&D department to obtain the preliminary experience of satellite positioning, verified the feasibility of satellite positioning, and paved the way for the development of GPS. Because of the great advantages of satellite positioning in navigation and the great defects of meridian system in submarine and ship navigation, the American army, navy and air force and civil departments feel an urgent need for a new satellite navigation system.