Nowadays, almost everything is centred on GPS. With the approval of the first basic unit for Instrument Flight Rules (IFR) usage in 1994, this incredible technology has completely transformed the aviation industry.
GPS is now deeply embedded in everyday operations. Many critical operations rely on it, including navigation, communication, surveillance, ADS-B, and TAWS. It’s a technology we depend on to ensure safety in the skies.
And here’s where the issue arises. For GPS systems to function properly, they rely on the radio signals sent by satellites. However, these signals are weak and vulnerable to deliberate interference. This probably isn’t news if you operate between America, Europe, and Asia.
The worrying thing is that these occurrences are becoming more common. According to reports from EUROCONTROL and the FAA, the number of GPS failures has increased dramatically over the last five years, with intentional interference being the main reason for this trend.
So, what is GPS jamming aviation, and what effects does it have on air navigation?
What is GPS Jamming, and How Does it Work?
What is GPS jamming aviation? GPS jamming is deliberately interfering with the regular functioning of GPS (Global Positioning System) signals. In most cases, a jammer is used for this purpose; it hinders the functionality of GPS receiver devices by blocking the signals sent by GPS satellites.
The jammer mimics GPS signals by using an oscillator to create an RF signal. The signal is then enhanced to a degree where it may effectively block or overwhelm GPS signals within a certain region. The jammer’s operating range can be adjusted by adjusting the amplifier.
An antenna sends the amplified signal out into the world, affecting GPS signals. This makes it more difficult, if not impossible, for the GPS receiver to differentiate between the real GPS signals and the ambient noise, as the signal-to-noise ratio drops.
The control circuit keeps an eye on everything and adjusts the strength of the amplifier and the frequency of the oscillator so that the jammer works exactly how you want it to.
GPS Jamming Types
The two main GPS jamming types are spoofing and blocking. The first two approaches below are illustrative of blocking techniques, while the third showcases spoofing.
- Narrowband jamming: To disrupt GPS signals, a jammer sends out signals within very limited frequency bands (2 MHz). This technique allows accurate targeting of hostile frequencies with little interference to neighbouring bands, protecting friendly messages from interference.
- Continuous Wave (CW) jamming: This easy-to-implement technique works by constantly sending out the signal of a single or restricted band of frequencies from a jammer. This floods receivers with an endless supply of unmodulated signals, making it impossible for them to process incoming signals.
- Modulation techniques: Multiple modulation methods can be used to obstruct GPS signals. While the aforementioned methods rely on noise and hence overload GPS, modulation methods send out signals that mimic real GPS signals.
With their help, GPS has a harder time distinguishing between real and fake data. Modulation methods include complicated interference, which hinders GPS receivers’ ability to latch onto the proper satellite signal, and spoofing, an attempt to trick a GPS device into thinking it is in a different place.
Impact of GPS Jamming on Air Navigation
The issue of GPS jamming is becoming more problematic since failures happen at random and unpredictable intervals. The majority of GPS outages (around 75%) occur during the cruise phase, with 10% of those instances experiencing outages longer than thirty minutes. There have also been cases when GPS devices lost signal and never recovered the signal again. Given the importance of GPS technology to contemporary aviation operations, this poses significant risks to air navigation and safety.
Even in the face of interference, most contemporary aeroplanes can still fly thanks to a suite of sensors and other sources that work in tandem with GPS to pinpoint their exact location. But pilots and industry insiders say that GPS is still the mainstay for airlines.
In many instances, the GPS will need to be turned off and cannot be reset for the rest of the flight if jamming or spoofing happens.
This can result in air traffic problems and disruptions. For example, some processes rely on GPS to work, therefore take-offs and landings may have to be modified according to the availability of other navigation aids. For both passengers and airline operations, this might mean more hassle and wait times.
Also, some private planes don’t have any other navigational aids other than GPS.
Furthermore, many systems on board planes use GPS and other GNSS systems. While mistakes in the passenger’s info screen’s rolling maps may not be life-threatening, problems with the Enhanced Ground Proximity Warning System (EGPWS), a system meant to enhance terrain avoidance safety, might have far-reaching consequences might have far-reaching consequences.
GPS jamming introduces inaccuracies, which impacts altitude calculations. Important safety alarms that tell pilots when their aircraft is dangerously near to the ground or an obstruction could be triggered if this happens.
False alarms might be sounded and pilots could be encouraged to perform avoidance actions that could put an aircraft in danger if these systems don’t know the aircraft’s location.
Conclusion
Both civilian and military navigators will need to adapt their strategies to counter the increasing prevalence of GPS jamming.
Since operators cannot afford to stop operations or avoid extremely jammed locations, they must depend on technology solutions, such as safeguarding GNSS connections, identifying when jamming is happening, and pinpointing its origin.
At Airport Gurus, we provide expert airport operations and technology assistance to help you navigate these challenges. Explore our airport technology solutions today!