Which type of navigational aid operates in the low and medium frequency range?

The type of navigational aid that operates in the low and medium frequency range is the NDB, or Non-Directional Beacon. NDBs transmit signals in the LF (Low Frequency) and MF (Medium Frequency) bands, typically between 190 kHz and 535 kHz. This allows pilots to receive radio signals that they can use for navigation, particularly in areas where more advanced navigational systems may not be available.

In contrast, VORs (VHF Omni-directional Range) operate in the VHF frequency range, generally from 108.00 to 117.95 MHz, making them unsuitable for this specific question. GPS (Global Positioning System) relies on satellite signals and does not fall under the frequency ranges specified in the question. Similarly, ILS (Instrument Landing System) uses both VHF and UHF frequencies for precision approach and landing, which also does not classify it within the low and medium frequency ranges.

Thus, the NDB is uniquely positioned as a navigational aid within the specified frequency range of low and medium frequencies.