# X.	Height above ground

The NAV is able to tell you how high from the ground you are. Thanks to topography data recorded by the Shuttle Radar Topography Mission realized in 2000 by Endeavour space shuttle (see <http://en.wikipedia.org/wiki/Shuttle_Radar_Topography_Mission>).

<mark style="color:red;">**From the Nav V3, the worldwide topography is already embedded in the instrument.**</mark>

&#x20;For the older versions of the Nav, here is the process to send the topography data into your instrument:

&#x20;1\)      You must go to our dedicated webpage: <https://www.syride.com/en/topography>

2\)      Then move the red rectangle to your selected fly area, and download the data.

3\)      Turn on and connect your NAV with the USB cable.

4\)      Then go in the SYS PC Tool, and click on the **“Send a file to my instrument”** icon, and select the file you previously downloaded.

5\)      Wait until the end ot the file upload and restart your instrument.&#x20;

<figure><img src="/files/aA1VuEKE43MgYqA6k2ls" alt=""><figcaption></figcaption></figure>

Caution, height above the ground has a precision of ±20m, plus the GPS precision (a few meters).&#x20;

<mark style="color:red;">**To display your height above ground, this information must be included in your screen configuration (see previous chapter) and you need GPS reception.**</mark>


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