Which statement best describes GPS use of spread spectrum?

Which statement best describes GPS use of spread spectrum?

• A. It uses narrowband transmissions.
• B. It uses spread spectrum techniques to improve robustness of signals.
• C. It does not use spread spectrum.
• D. It uses only FHSS.

Answer: (B)

Spread spectrum is used by GPS to spread each satellite’s signal over a wide bandwidth using a unique pseudorandom code. This spreading provides processing gain, which improves the signal-to-noise ratio and makes reception more robust in the presence of interference, jamming, and multipath. It also enables multiple satellites to transmit on the same general band simultaneously, since each satellite’s code lets the receiver separate their signals. GPS does not rely on narrowband transmission or frequency hopping; it uses spread-spectrum CDMA-like spreading with PRN codes. So the statement that GPS uses spread spectrum techniques to improve robustness is the best description.