Hello. I am trying to set antennas into Linear Array (ULA) in order to improve accuracy, but I can not quite comprehend how to read the DOA angles correctly. I have created this beautiful image, which shows the linear antenna and 4 measurement cases:

Test1 - the radio is 45 degrees relative to the array line

Test2 - 90 degrees

Test3 - 135 degrees

Test4 - 180 degrees (the radio is on the line with the array)

I have noticed that the signal is mirroring over the line 90*-270*, i.e. the Kraken is not sure where it is - at the front or behind the array (which is fine). But is line 90-270 the line of the array? I.e. is 90* DOA mean that the radio at the left from the antenna array, 180* - at the front (or behind), and 270* - at the right?

I believe the probability of output being 45* vs 135* is the same, right? Also, are there any corner cases with the DOA output that may need knowing? Thank you

Yes the two solutions are equally valid. If you have some prior knowledge about the signal direction, you might be able to rule one out.

Alternatively, if are driving around you’ll find that the true angle will converge, whilst the false angle will diverge. So in time you will get the solution.

But ULA on a car could be slower to converge compared to UCA. Since there is only a limited range of usable angles. You’ll see that for signals coming from the +90 / -90 ends of the array (like in Test 4) you’ll get very poor results, so only mostly orthogonal signals will work well.

This is because the array looks very tiny from the sides so you loose aperture. With the worst case being that the array looks like a single element from the +90 / - 90 degree angles.