This document provides an overview of the Global Positioning System (GPS). It describes GPS as a satellite-based navigation system that uses 24 satellites to pinpoint the precise location, altitude, and time. It explains how GPS works by transmitting signals from the space segment satellites to receivers in the user segment. The signals allow receivers to calculate their position by determining the time difference of signals arriving from multiple satellites. The document outlines the key components of GPS including the signals, position determination process, receiver components, applications such as navigation, and future developments for GPS technology.