Acoustic azimuth and elevation are ENU referenced

[braanan]

Hi @arjo129,

Capturing info from our conversation yesterday in this issue. Thanks again for your time.

I ran a simple test with one vehicle (at the origin) and an "acomms box" (20 m east) as shown below:

The vehicle ranged the box using a simple test mission:
./bin/LRAUV -x "RegressionTests/IgnitionTests/testAcTracking.xml"

In the test the vehicle and box are both on the same vertical plan (depth of 0 m) and the vehicle is pointed directly at box, so the expectation is to get range: 20 m, and azimuth/elevation close to 0 degrees, but instead we got:
2022-03-15T00:10:33.012Z,1647303033.012 [DAT](INFO): Received range message from 201. Range: 19.220531 m, Azimuth: 92.087051 deg, Elevation: -179.999771 deg.

So range seems to be roughly correct but azimuth is 90 degrees off (not sure about elevation). As you suggested, it seems like the acomms link needs to be rotated from ENU to NED.

Note that azimuth is expected to be in (-180, 180) positive starboard, and elevation is expected in (-90, 90) positive down.

Thanks

[chapulina]

@arjo129 , this gif from #163 shows the current model frame, which is a weird "SFU" (starboard-forward-up)

You can also visualize the link frames with right-click -> view -> frames. Most of them are oriented "BSU" (back-starboard-up).

So while working on this, you need to be mindful of whether you're using the model frame, some link frame, or something else.