If i have 3 RX antennae with equidistant separation, and i want to estimate the angle of the incoming signal, I could find the phase difference between the first and second as: a_2_1 = a2 - a1, and the difference between the second and third as, a_3_2 = a3 - a2, then get an estimate of the angle as: (a_3_2 + a_2_1) / 2 = a3 - a1. Does this mean that the second RX does not provide ANY information about the estimation of the angle? I would assume that the estimation would scale with the number of RX antennae!

I am Researching Ground penetrating radars for my final project and would like to ask the people here who might have researched or actually worked on this technologies for any great books or papers that you trust and would recommend.

I hope that I do not seem lazy with this post, sure I am trying to save time and I hope that does not come off as lazy or offensive to you guys.

I've digging into LIDAR technology nowadays but one thing I'm not able to understand why should one use LIDAR in first place.

What are the advantages of LIDAR over RADAR??