What is the inclination to the equatorial plane of the satellites in the NAVSTAR GPS constellation?

The correct inclination to the equatorial plane of the satellites in the NAVSTAR GPS constellation is approximately 55 degrees. This inclination is significant for several reasons, primarily related to the satellite's orbital mechanics and coverage efficiency.

An inclination of 55 degrees allows the GPS satellites to provide good coverage for both mid-latitude and high-latitude regions of the Earth. It is a compromise that ensures that the satellites are able to maintain visibility from various points on the ground, which is essential for accurate positioning and navigation.

This inclination also helps minimize the potential for satellite signal interference, as it prevents the satellites from being too clustered in similar orbital planes, thereby improving the geometry of satellite positioning for users on the ground. Consequently, this geometry allows for more effective triangulation of signals, ultimately resulting in better accuracy in determining the user's location.

In contrast, other inclination values such as 45°, 35°, or 65° either do not provide the optimal coverage needed for GPS functionality or would not facilitate the desired satellite geometry for precise navigation.