GPS Navigation
The aviation industry is a global network responsible for connecting people, goods, and services across continents and relies heavily on navigation systems to ensure safe, efficient, and accurate flight operations. Among the many technological advancements, the introduction of Global Positioning System (GPS) has been a revolutionary force, reshaping both the efficiency and safety of air travel. A testament to American ingenuity and technological progress, it’s been over 50 years since its inception. Let’s dive into the practical applications of GPS, from route planning to precise landing approaches, we’ll discuss its critical role in modern flight operations.
Origins of GPS in Aviation
GPS technology was originally developed by the U.S. Department of Defense in the 1970s for military applications. However, in the 1990s, civilian access to GPS became more widespread, allowing the aviation industry to embrace it fully. Before GPS, pilots primarily relied on ground-based navigation aids like VOR (Very High Frequency Omnidirectional Range) and NDB (Non-Directional Beacon) systems, both of which had their limitations in terms of coverage, accuracy, and operational flexibility.
The GPS system consists of a network of satellites orbiting Earth, constantly transmitting time and location data. Aircraft equipped with GPS receivers can determine their precise position, speed, and altitude anywhere in the world, regardless of weather conditions. This high level of precision has made GPS indispensable in every phase of flight, from takeoff to landing, and has contributed to the modernization of the entire airspace system (FAA, 2016, p. 3-13).
Why is GPS so Important?
Precision Route Planning
Enables pilots to chart accurate flight paths, optimizing fuel efficiency, and reduce travel time.
Enhanced Safety Measures
With real-time data, GPS systems provide critical information for avoiding obstacles and adverse weather conditions.
Accurate Landing Approaches
Assists in executing precise landing procedures, even in low-visibility conditions, ensuring passenger safety.
Global Coverage
Offers worldwide accessibility, allowing seamless navigation across international airspaces without interruption.
GPS technology has enabled various advancements in aviation, primarily by improving navigation accuracy and safety. Let’s briefly touch on several applications that demonstrate how GPS has been integrated into aviation operations.
Flight Planning and En Route Navigation
Before a flight, pilots create a flight plan, which includes the most efficient route from departure to destination. Historically, this process relied on following airways and navigating from one ground-based station to another. GPS has transformed this system by enabling aircraft to fly more direct routes without relying on ground-based navigational aids (U.S. Space Force, 2022). This not only reduces flight distances but also decreases fuel consumption and time spent in the air (Southwest Airlines, 2021).
Precision Approaches and Landing
In the past, landing an aircraft in low visibility required specialized ground-based systems like the Instrument Landing System (ILS). While highly accurate, ILS infrastructure is expensive to install and maintain, meaning only major airports typically had this equipment. GPS, however, provides the foundation for Performance-Based Navigation (PBN) and Required Navigation Performance (RNP), allowing aircraft to perform precision approaches at airports that lack traditional ILS systems. This has significantly expanded the number of airports where precision
approaches are possible, increasing accessibility and safety at smaller and more remote airports (ICAO, 2020).
Traffic and Terrain Awareness
GPS is also central to modern traffic collision avoidance systems (TCAS) and terrain awareness and warning systems (TAWS). These systems use GPS-derived location data to provide real-time information about nearby aircraft or obstacles, giving pilots valuable situational awareness in critical moments. TCAS, for instance, uses GPS to monitor nearby aircraft positions and speeds, alerting pilots if they are on a potential collision course. TAWS, meanwhile, warns pilots if their aircraft is approaching terrain or obstacles that pose a risk of collision, especially in
low-visibility conditions such as night or poor weather. Both systems help pilots make timely decisions and corrective actions to prevent collisions (FAA, 2016, p. 2-30).
Search and Rescue Operations
In the event of an accident, an aircraft equipped with GPS-based tracking systems, such as Automatic Dependent Surveillance-Broadcast (ADS-B), can transmit precise locations in real-time (FAA, 2023). This information is crucial during an emergency, allowing rescuers to respond quickly and accurately to the aircraft’s last known position. This contrasts with older systems, where finding a missing aircraft could take days or even weeks.
Planning, Navigation, & Landing
Route Planning
Allows pilots to plot efficient and safe routes, optimizing fuel consumption, and reducing travel time.
In-Flight Navigation
Provides real-time data, ensuring accurate positioning and helping pilots navigate through complex airspaces.
Precision Landing
Assists in precise landing approaches, enhancing safety by providing accurate altitude and location data, even in poor visibility.
Impacts of GPS on Aviation
A Stanford University study discovered that GPS adoption by Alaska Airlines has resulted in $19 million yearly in savings, prevented 831 flights from delay or cancellation, reduced fuel consumption by 210,000 gallons, and reduced flight time by 3 minutes per flight using GPS RNAV (Enge, Walter, & Eldredge, 2014, pp. 5-6).
Thousand Minutes Saved
Thousand Gallons Fuel Saved
Million Dollars Saved
Reduced Delays
Recent Innovations
GPS now combined with automation systems such as the Air Force Research Laboratory’s (AFRL) Automatic Ground Collision Avoidance System (Auto GCAS), can detect and prevent aircraft from flying into the ground. The AFRL team has been testing the system on military aircraft since 2014 and as of July 2020, the system has saved the lives of 11 pilots and 10 aircraft. AFRL’s Whitney Wetsig explains, “Auto GCAS saves pilots’ lives by preventing controlled flight into terrain, the most common cause of aircraft losses and fatalities in fighter aircraft (Wetsig, 2021).
Conclusion
GPS in the aviation industry has been extraordinarily transformative. From improving en route navigation to enhancing safety during landing, GPS has become a vital tool in modern aviation. The continued evolution of GPS and related technologies promises to make aviation safer, more efficient, and more sustainable. As the aviation industry grows and modernizes, GPS will remain at the forefront, ensuring that aircraft can fly with unparalleled accuracy and reliability. Leave a comment, we would love to hear your thoughts.
References
Enge, N., Walter, T., & Eldredge, L. (2014). Aviation Benefits from Satellite Navigation. 5-6. Retrieved October 10, 2024, from https://web.stanford.edu/group/scpnt/jse_website/documents/Enge-Aviation_Benefits_from_GNSS.pdf
Federal Aviation Administration (FAA). (2016). Pilot’s Handbook of Aeronautical Knowledge (2016 ed.). Oklahoma City, Oklahoma: United States Department of Transportation, Federal Aviation Administration. Retrieved October 11, 2024, from https://www.faa.gov/sites/faa.gov/files/2022-03/pilot_handbook.pdf
Federal Aviation Administration (FAA). (2023, January 17). Automatic Dependent Surveillance-Broadcast (ADS-B). Retrieved October 11, 2024, from FAA.gov: https://www.faa.gov/air_traffic/technology/adsb
Federal Aviation Administration (FAA). (2024). NextGen Performance Reporting and Benefits. Springfield: United States Department of Transportation, Federal Aviation Administration. Retrieved October 10, 2024, from https://www.faa.gov/nextgen/reporting-benefits
International Civil Aviation Organization (ICAO). (2020, August 20). Fact Sheet – NextGen and Performance-Based Navigation. Retrieved October 10, 2024, from U.S. Mission to the ICAO: https://icao.usmission.gov/fact-sheet-nextgen-and-performance-based-navigation/
Southwest Airlines. (2021). One Report Environmental Snapshot. Southwest Airlines. Retrieved October 10, 2024, from https://www.southwest.com/assets/pdfs/communications/one-reports/2021-One-Report-Environment-Snapshot.pdf
U.S. Space Force. (2022, February 10). Aviation. Retrieved October 11, 2024, from GPS.gov: https://www.gps.gov/applications/aviation/
Wetsig, W. (2021, July 01). AFRL commended for life-saving collision avoidance technology. (Air Force Research Laboratory Public Affairs) Retrieved October 10, 2024, from Air Force Material Command: https://www.afmc.af.mil/News/Article-Display/Article/2682711/afrl-commended-for-life-saving-collision-avoidance-technology-integrated-air-an/
Hey Steve, this blog is extremely impressive! It looks like you were super thorough in your study. I had ZERO clue that Dod invented GPS, I would’ve guessed the phone companies did lol!
Quick question: You mentioned how GPS helps responders quickly find the aircraft in the event of an emergency. You also mentioned that in the past it could take days or weeks! What did they use before GPS to help them locate the aircraft?
Again, excellent job!
Joslyn,
Thank you for your kind reply and to answer your question, aircraft are equipped with an emergency locator beacon that responders can tune equipment to and listen for. This beacon emits a radio pulse on a continuous basis until the battery is depleted. Prior to GPS, responders would narrow the search as much as possible based on the last known radar position and the flight plan route. However, the aircraft could have been off course or out of radar range, as is common for international flights. The search area could be 20 km or wider along the estimated path. Search and rescue operations conduct a grid based search, back and forth looking for debris or survivors. Emergency locator beacons now transmit on frequencies that satellites can track down to 2 km. Additionally, aircraft equipped with ADS-B and/or two-way GPS transmitters are constantly updating the ADS-B network with their positioning data. These technologies greatly reduce the search area and narrow responder efforts.