hi, all
We made the AOA board by ourselves, and the measurement found that the angle value obtained when the label is rotated will be different, similar to the PDOA-Primer.pdf document, Figure 4 Path difference distortion.
As shown below, but the horizontal axis is the real pd, and the vertical axis is the 12 measured values of the label at different angles. -2 ~ 0 corresponds to -90 degrees ~ 0 degrees, and 0 ~ 2 corresponds to 0 ~ 90. Degrees, you will find that there will be a gap of 45 degrees. In this case, even if I do a nonlinear fit or look up the table, there will be an error of at least 22.5 degrees when walking randomly with the label, which will cause a very bad Positioning effect.
what reason will result in the issue ? how to slove it?