How does an airplane’s navigation system work?

Have you ever wondered how pilots know where they are going? Airplanes travel thousands of miles across the sky, and although the horizon looks the same everywhere, they still manage to reach their destination with precision.

Piloting an airplane to its destination is more like sea navigation than driving a vehicle such as a car: an airplane, like a ship, relies on a complex navigation system that allows the pilot to navigate through the clouds.


The navigation instruments available to the pilot include all the systems onboard the aircraft and the radio guidance that allow the pilot to determine the position of the aircraft.

At the start of the flight, the pilots load a predetermined route into the flight management system: once the route is set, the pilots can follow it on their screen during the flight. They can also monitor, around their flight path, many elements such as the presence of other airports, other planes, mountains, or bad weather.

On-board navigation systems can be divided into the following categories:

  • the Global Navigation Satellite System (GNSS);
  • Inertial navigation system (INS);
  • Flight Management System (FMS).


It is the set of navigation systems used to know the coordinates, altitude, speed, and other parameters of the aircraft. The best-known systems of this type are GPS (Global Positioning System, GLONASS (globalnaïa navigatsionnaïa spoutnikovaïa Sistema), or “global satellite navigation system”, a satellite positioning system of Soviet origin), and Galileo (satellite positioning system developed by the European Union), which use radio geolocation using a network of artificial satellites in orbit.

airplane navigation


The INS is an autonomous system that can track our location using accelerometers and gyroscopes. At the start of the flight, when the plane is still on the ground, the pilots tell the system the exact position in terms of latitude and longitude.

From this moment, the INS detects the movements made on any axis and then calculates the position of the plane according to this movement. It does not require any external input other than the coordinates entered at the start of the flight.


Once the route is determined, the information is fed into the Flight Management System (FMS), which we could think of as the brain of aircraft navigation.

Its mission is to help pilots in the calculation of flight parameters and therefore in the management of navigation. The FMS facilitates the work of pilots, which also increases flight safety.

Here are some features of this system:

– it is used to configure the autopilot to follow the route set before takeoff;

– it configures the take-off and approach routes and the information provided by the flight controllers;

– it helps in the calculation of flight parameters;

– it recommends power settings to reduce fuel consumption;

– it estimates the arrival time based on the route.

Flight managment system


Today, thanks to the possibility of performing instrument flights, radio guidance is rarely used in the cruise phase. However, radio guidance still plays an essential role in the initial phases of take-off, approach, and landing.

Radio guidance transmits radio signals that the pilot receives by tuning the onboard equipment to the corresponding frequencies. Once the route has been determined, it is sent electronically to air traffic flow management. Air Traffic Flow Management (ATFM) analyzes the proposed route and determines if current air traffic can support the route. The local air traffic controller will inform the pilot during take-off if the road is clear. If so, the pilot can proceed.

As you may have already understood, it is very difficult for a pilot to get lost thanks to this complex navigation system: there is a lot of information and what matters, in the end, is knowing the interpretation correctly.

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Active Avionics Engineer and aircraft lover. I want to share informational articles about the aviation field

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