Please briefly describe the main functions of GPS.

answer: ① field exploration. The field exploration function of GPS mainly includes surveying and mapping and resource exploration.

② modern transportation. GPS provides real-time, all-weather and global navigation services in land, sea and air.

③ travel. Tourists can know their position, walking speed and direction at any time by carrying GPS receivers with them, and will not get lost.

④ military. At present, GPS is widely used in combat command, emergency search and rescue, military ship navigation, military aircraft navigation, artillery, surface-to-air missile precision guidance and other fields.