What is one of the systems that GPS can substitute for?

Global Positioning System (GPS) provides precise positioning and navigation capabilities that can effectively serve as a substitute for older navigational systems, such as the Automatic Direction Finder (ADF). The ADF relies on radio signals from nondirectional beacons to determine the aircraft's bearing relative to the station.

In contrast, GPS offers a much more accurate and reliable means of navigation, utilizing satellites to provide real-time position data. This advantage allows pilots to navigate directly to waypoints or route points without the limitations associated with the ADF, such as signal interference and range issues. Therefore, the implementation of GPS can enhance navigational accuracy and situational awareness for pilots, making it a strong alternative to ADF.

Although other systems like DME (Distance Measuring Equipment), VOR (VHF Omnidirectional Range), and ILS (Instrument Landing System) have their own navigational roles, their functions cannot be directly substituted or completely replaced by GPS in the same practical manner as the ADF.