What are benchmarks in the context of GPS systems?

In the context of GPS systems, benchmarks refer to known points that have precisely established locations. These points are crucial for calibrating GPS measurements, as they provide a reference for accuracy. By using benchmarks, GPS devices can correct for any errors in their calculated positions, ensuring that geographic data collected is reliable and precise.

These known points often correspond to physical markers placed by surveyors, often with documented elevation and geographic coordinates. When a GPS receiver is utilized in proximity to these benchmarks, it can evaluate the discrepancies between its readings and the established coordinates to improve the accuracy of future GPS measurements. This makes benchmarks vital in various applications, including surveying, navigation, and cartography, where precision is necessary.

In contrast, the other options don't accurately capture the role of benchmarks. Temporary survey points typically aren't known with the same precision as benchmarks, measuring signal strength pertains more to analyzing the quality of GPS signals rather than calibration, and coordinates for calculating elevation do play a role in GPS but do not specifically define what benchmarks are. The focus on exact locations for calibration is central to understanding benchmarks in GPS systems.