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If you tune in a NAV frequency into your G1000 the ID of the Nav Aid will be shown next to the frequency after some time. In this example SEA:

enter image description here Source: http://krepelka.com

How does this work? Because we know that there is the possibility that two VORs could have the same frequency, so the frequency is not uniquely bound to an identifier.

I have two assumptions:

  1. The Garmin is listening to the morse code, transfers it into the letters and shows it in the display.

  2. The Garmin is checking the Nav database and searches for the frequency and takes the identifier of the closest, based on the GPS position.

Which one is right, or is there even another way Garmin does it?

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Garmin doesn't explicitly state the method in the documentation I can find, but I believe the answer is #1. It decodes the Morse code and displays that value. I say that for two reasons:

First; Garmin, like most successful aviation companies, makes it a habit to reuse technology where it can. Volumes are low and certification costs are high so using the same NAV receiver in more than one product saves costs and increases profit. From their web site, the GNC 225 decodes the ident.

  • Automatically displays tuned frequency's navaid or airport identifier
  • Automatically decodes Morse signals so you don't have to

Second; the fact that it takes several seconds for the ID to display indicates it's being decoded as it has to be received before it's displayed. If it were pulled from the database, it would be available almost instantly.

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  • $\begingroup$ Sometimes the ID comes up really fast so I thought that would be impossible... But maybe you will get the ID a lot earlier than a bearing on the HSI. $\endgroup$ – Pascal Ackermann Feb 20 at 19:31
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Since the only way to verify that you are receiving the correct signal from a working VOR is to listen to the Morse Code, it is very likely that the G1000 is decoding the Morse Code. If it were only using the database, the pilot is likely to miss a test code or the fact the code is missing all together in the case of a facility under maintenance.

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