全球定位系統（英語：Global Positioning System，通常簡稱GPS），又稱全球衛星定位系統，是美國國防部研製和維護的中距離圓型軌域衛星導航系統。它可以為地球表面絕大部分地區（98%）提供準確的定位、測速和高精度的標準時間。

Global Positioning System (English: Global Positioning System, usually referred to as GPS), also known as Global Positioning System, is a medium-distance circular orbit satellite navigation system developed and maintained by the US Department of Defense. It can provide accurate positioning, speed measurement and high-precision standard time for most areas (98%) on the earth's surface.

 GPS中繼器系統用於將衛星信號帶入室內，在通常不存在的區域內提供定位和定時信號。

GPS中繼器是用於將信號傳輸到通常無法到達的地方的設備。它們通過使用位於建築物外部的天線接收衛星信號，並將信號重新傳輸到室內區域或覆蓋空間來運行，從而可以一致且不間斷地訪問地下或其它難以到達的區域的信號。使用重傳信號意味著 GPS 接收器正在跟踪當前 GPS 狀態，這樣當接收器從室內移動到室外時，接收器立即跟踪位置，而不是花幾分鐘時間獲取當前GPS 狀態。 

A GPS repeater system is used to bring satellite signals indoors, providing positioning and timing signals inside areas where not usually present.

GPS repeaters are devices that are used to transmit signals to places where they normally cannot reach. They operate by receiving satellite signals with an antenna located outside of a building, and re-transmitting the signals to the indoor area or covered space, resulting in consistent and uninterrupted access to signals underground or in other hard-to-reach areas. The use of re-transmitted signals means that the GPS receiver is tracking the current GPS status, so that when the receiver is moved from indoors to outdoors, the receiver is instantly tracking the location, instead of taking several minutes on the acquisition of the current GPS state.