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We can see the effect of the tailwind on the plane's flight direction on the modern military fighter jet huds. I wonder about how can the avionic systems detect tailwind and which sensors using in the process.

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    $\begingroup$ It just has to compare it's airspeed and heading, taken from pitot and INS data to ground speed and track from GPS $\endgroup$ – TomMcW Jul 6 '17 at 19:27
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    $\begingroup$ In simple terms, at any given power setting and altitude a given aircraft will travel at a certain speed. Let’s say it’s 500 kts. The GPS in the aircraft can tell the groundspeed. Let’s say it’s 600kts. Then the tailwind is 100 kts. The concept is simple, but the implementation more difficult. Small aircraft pilots actually do a lot of this in their head to get rough estimates of the windspeed and direction. It is especially important when entering holding patterns and when landing with a crosswind. $\endgroup$ – JScarry Jul 6 '17 at 19:29
  • $\begingroup$ It seems a complicated sensor fusion process including INS (Accelerometers, Gyros and Compasses) and GPS for ground speed and Pitot system for true air speed and compare both of the vectors. In that case we can calculate the angle of attack with similar way. $\endgroup$ – Batu92k Jul 6 '17 at 19:40
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    $\begingroup$ @JScarry: It is not even a question of altitude and power setting. Airspeed is known from the Pitot tube. Ground speed is known from GPS. The difference is your headwind/tailwind component. $\endgroup$ – abelenky Jul 6 '17 at 19:48
  • $\begingroup$ @abelenky True airspeed goes up about 2% per 1000' above standard atmosphere, so altitude matters a bit in the calculation. But you are correct, power settings don’t matter—I’ve had too much partial panel practice lately and I have power settings on the brain. $\endgroup$ – JScarry Jul 6 '17 at 20:22
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This can be sensed by means of either an INS or GPS to determine a ground velocity and both the data from the pitot static system and a magnetometer to determine the true air velocity. The local wind velocity is the difference between the ground velocity and the true air velocity.

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