Final answer:
Signal propagation delay refers to the time required for a signal to travel from sender to recipient, a concept critical for the function of GPS satellites which must account for special and general relativistic effects to maintain accuracy.
Step-by-step explanation:
The term you're looking for is signal propagation delay, which refers to the time it takes for a signal to travel from the sender to the recipient. When dealing with satellite transmission, this delay can be significant due to the great distances involved. Satellite systems, like GPS, must adjust for the effects of both special relativity and general relativity to maintain accuracy. Special relativity comes into play because the satellites are moving at high speeds relative to the observer on Earth. General relativity is considered because satellites are in a weaker gravitational field. If these relativistic effects are not accounted for, GPS accuracy would deteriorate swiftly.
For instance, GPS satellites are equipped with very accurate clocks that are synchronized to consider the effect of time dilation due to their velocity and the weaker gravitational force at their altitude. Additionally, spacetime curvature near large masses like the Sun can also significantly affect the travel time of light or radio waves, as demonstrated by the time delays experienced by radio signals from the Viking lander on Mars.