What are the positioning signal frequencies used in GPS?

• A. 1227.60 MHz and 1600.00 MHz
• B. 1150.00 MHz and 1650.00 MHz
• C. 1575.42 MHz and 1227.60 MHz
• D. 1400.00 MHz and 1500.00 MHz

Answer: (C)

GPS positioning relies on two primary carrier frequencies in the L-band: L1 at 1575.42 MHz and L2 at 1227.60 MHz. The civil signal is modulated on L1 (C/A code), while L2 carries the P(Y) code for military use and the modern L2C civil signal. Using both frequencies enables ionospheric delay correction, because the ionosphere affects signals differently at different frequencies, leading to more accurate range measurements. The other frequency options listed do not correspond to GPS carrier frequencies, which is why they aren’t correct.