A GPS/GNSS repeater is a device used to enhance GPS/GNSS signal coverage within a specific area. It receives GPS/GNSS signals from satellites and then retransmits them at a higher power or different frequency, effectively extending the range of the GPS/GNSS signal indoors or in areas where the signal may be obstructed by buildings or terrain. 

GEMS GPS and GNSS repeaters are commonly used in environments like underground parking garages, tunnels, buildings with thick walls, or any other location where GPS/GNSS signals struggle to penetrate. By installing a GPS repeater, users indoors can still receive accurate GPS positioning without relying solely on outdoor signal reception. This can be crucial for applications such as navigation, tracking, and timing synchronization in various industries including transportation, logistics, and telecommunications.