Final answer:
The two frequencies used to modulate the localizer frequency of the airport's ground localizer transmitter are the carrier frequency and the sideband frequency.
Step-by-step explanation:
The two frequencies used to modulate the localizer frequency of the airport's ground localizer transmitter are called the carrier frequency and the sideband frequency.
The carrier frequency is the main frequency that is modulated with the information or signal. In this case, the carrier frequency is the localizer frequency of the ground localizer transmitter.
The sideband frequency, on the other hand, is the frequency that carries the modulated information. It is produced by shifting the carrier frequency up and down by a certain amount, known as the modulation index. The sideband frequencies are typically located above and below the carrier frequency.
For example, if the localizer frequency is 108 MHz, the carrier frequency might be 108 MHz and the sideband frequencies could be 108.1 MHz and 107.9 MHz.