Which statement differentiates ILS from GLS RNAV approaches?

Which statement differentiates ILS from GLS RNAV approaches?

• A. ILS uses GPS for all guidance
• B. GLS RNAV uses ground-based localizer and glide slope
• C. ILS is a non-precision approach
• D. ILS uses ground-based localizer and glide slope; GLS RNAV uses satellite-based augmentation

Answer: (D)

Guidance source differentiates these approaches. ILS uses ground-based transmitters: a localizer for horizontal (lateral) guidance and a glide slope for vertical guidance, both located at the runway end, making it a traditional precision approach. GLS RNAV relies on satellite navigation (GNSS) with augmentation to provide precise lateral and vertical guidance along the approach path, without ground-based localizer and glide slope antennas. So the correct distinction is that ILS uses ground-based localizer and glide slope, while GLS RNAV uses satellite-based augmentation to achieve precision guidance. The other statements don’t fit because ILS is not GPS for all guidance, GLS RNAV does not use ground-based localizer/GS, and ILS is a precision approach, not non-precision.

Guidance source differentiates these approaches. ILS uses ground-based transmitters: a localizer for horizontal (lateral) guidance and a glide slope for vertical guidance, both located at the runway end, making it a traditional precision approach. GLS RNAV relies on satellite navigation (GNSS) with augmentation to provide precise lateral and vertical guidance along the approach path, without ground-based localizer and glide slope antennas. So the correct distinction is that ILS uses ground-based localizer and glide slope, while GLS RNAV uses satellite-based augmentation to achieve precision guidance. The other statements don’t fit because ILS is not GPS for all guidance, GLS RNAV does not use ground-based localizer/GS, and ILS is a precision approach, not non-precision.