What is the advantage of a dual-frequency GPS receiver?

• A. Much of the ionospheric delay error can be eliminated
• B. It increases the number of channels required
• C. It reduces the need for a local oscillator
• D. It increases power consumption

Answer: (A)

Using two frequencies lets a GPS receiver estimate and remove the ionospheric delay, which changes with frequency. By comparing the delays on the two signals, the ionospheric term can be canceled out, yielding a much more accurate position. This is especially valuable for high-precision needs, long baselines, or when ionospheric activity is strong.

The other points are more about hardware trade-offs than the main benefit. Dual-frequency reception typically adds some channel capability and power use, and it still requires stable oscillators, so those aren’t the primary advantage.