What are the working satellites and on-orbit backup satellites of GPS satellite constellation?

The working satellite of GPS constellation is 2 1, and there are 3 standby satellites in orbit.

A system for real-time navigation and positioning on a global scale. It consists of three parts: the space part-GPS satellite constellation; Ground control part-ground monitoring system; User equipment part --GPS signal receiver. There are 2 1 working satellites and 3 in-orbit backup satellites in the GPS constellation.