Question 967Navigation General

The correct answer is C) It may be suspended without warning. This is correct because the GPS system is controlled by the U.S. government, and they have the ability to suspend or degrade the GPS signal without advance notice for national security reasons. While GPS is generally reliable, it is considered a supplemental navigation system that should not be solely relied upon, as the signal can be interrupted or degraded at any time. The other answer choices are incorrect: A) Two position lines are used to give a 2D fix - This is not strictly true, as a GPS receiver can determine a 3D position (latitude, longitude, and altitude) from a minimum of 4 satellites. B) There are 12 functioning GPS satellites at present - The exact number of functioning GPS satellites can vary, but there are typically more than 12 available for use. D) It cannot be used in all parts of the world - GPS signals can be received globally, although the accuracy may be reduced in certain areas.