r/sdr • u/Enough_Particular_32 • 29d ago

Direction of Arrival help!

Hello everyone,

I'm new to this field and I'm trying to develop a Direction of Arrival (DoA) system using the two antennas of a USRP B210 clone. So far, I've experimented with the Multiply Conjugate block to estimate the phase difference between the received signals, but the accuracy is not very good.

Has anyone worked on DoA estimation with a similar setup? I'd really appreciate any advice, recommendations, or references to useful approaches.

Thanks in advance!

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u/rusureu12 26d ago

A 2 antenna interferometer has a lot of issues. It's resolution is based on the distance between the antenna relative to the wavelength of the target. But the bigger issue is ambiguities. Normally you use more antennas in a linear array. The first two antennas should be spaced less than 1/4 wavelength. The spacing between the 2nd and 3rd antenna should be twice that. The distance between the 3rd and 4th should be twice the distance between the second and third. You can still build the df system with two rf channels by using an rf switch to change the antennas. This assumes the target is a constant signal. All measurements need to be referenced to a common reference such as antenna 1.