Which of the following statements about GPS systems is accurate?

GPS systems rely on signals from satellites to determine a user's precise location, and one of the key technical requirements for accurate positioning is the ability to receive signals from multiple satellites. Specifically, GPS units need data from at least four satellites to triangulate their position accurately in three-dimensional space (latitude, longitude, and altitude). The fourth satellite helps in refining the accuracy of the location calculation by providing additional data that accounts for potential timing inaccuracies in the signals received.

This principle is grounded in the way GPS technology operates, utilizing the concept of trilateration, which requires signals from multiple points to pinpoint an exact position. The more satellites a GPS receives data from, the more accurate and reliable the positional information can be, especially in terms of elevation accuracy.

The other statements about GPS systems do not hold true in this context. For example, GPS devices do not require internet access, as they can function independently based on satellite signals. They also require a clear view of the sky to maintain a connection with satellites, and while many GPS units are portable, there are fixed installations where GPS technology is applied, demonstrating that portability is not a defining characteristic of all units.