Select the two true statements from the following list.

Question 7Select one or more:

Radio waves travel slightly more slowly in the Earth's atmosphere than in a vacuum. If a GPS receiver did not make correction for this it would calculate a distance from a satellite that was slightly too small.

There is no way of correcting completely for the speed variations, but the GPS system does have a built-in correction factor for an average situation.

None of the following is a permitted number of bits for a pseudo-random binary sequence: 6, 13, 31, 144.

Differential GPS can enable a GPS receiver to make full correction for errors that are due to the fact that radio waves travel more slowly in the Earth's atmosphere than they do in a vacuum.

Multipath propagation is caused by radio signals reflecting off nearby buildings or other objects at or near the ground.