What is a primary feature of the Global Positioning System?

The primary feature of the Global Positioning System (GPS) is its ability to provide accurate location data 24 hours a day. GPS relies on a constellation of satellites orbiting the Earth, which transmit signals to GPS receivers. These receivers calculate their precise location by triangulating signals from multiple satellites, regardless of time or weather conditions. This consistent and reliable access to location data makes GPS a crucial tool in navigation for various applications, including maritime, aviation, and land-based uses.

The other options present inaccurate characteristics of GPS. For instance, GPS does indeed rely on satellite signals for providing data, so it cannot function without satellite assistance. It is not restricted only to coastal waters; GPS can provide location information anywhere on the globe, including in remote inland areas and even out at sea. Additionally, GPS is not limited to land-based measurements; it is utilized across different domains, including air and sea navigation, making it versatile and broadly applicable.