Which coordinate system is used by the NAVSTAR GPS receiver for position determination?

The NAVSTAR GPS system utilizes the WGS 84 (World Geodetic System 1984) coordinate system for position determination. This global reference frame provides a consistent geodetic framework for navigation and mapping worldwide. WGS 84 includes a standardized set of parameters that describe the Earth's shape, such as its ellipsoid model, to accurately represent geographic locations in three-dimensional space.

WGS 84 is instrumental for the GPS system as it facilitates the integration of satellite data to compute positions. The system is designed to meet the requirements for various applications, including military, civilian, and aviation usage, allowing accurate and reliable positioning across the globe.

In contrast, the other choices represent different geodetic systems that either are region-specific or less commonly used in GPS technology. For example, PZ-90 is a geocentric coordinate system used in Russia, ED 87 and ED 50 refer to European datum systems that are more localized to specific geographical regions. These alternatives do not provide the global applicability and precision required for the functionality of GPS systems.