Radio Direction Finding came up the other day, and that's one of the uses for something like this. Along the same lines, there is a project out there to provide an "off the shelf" coherent RTL-SDR receiver array:

https://www.crowdsupply.com/krakenrf/krakensdr

That being the successor to KerberosSDR:

https://www.rtl-sdr.com/ksdr/

Looking forward to getting my hands on a KrakenSDR later this year, hopefully.

Later this year is a possibility. The (hopefully) final prototype is currently being built. We already have stock of the long-lead time components (TCXO, R820,RTL2832U), and the updated software is already working. The only downside is that the initial production run will be for only 1000 units.

Nice. I imagine it's early to be asking this, but any (approximate) idea how much the KrakenSDR units will sell for?

We are trying really hard to keep it at $299.

I would totally buy one.

Does your project have an RSS feed anywhere?

All I can find is CrowdSupply's "email me" form, which is basically an invitation for them to spam me about ten jillion other crowdfunds that I am not interested in. Your project would get lost in the noise.

I didn't realize they were generally spammy and not limiting updates to just the single, subscribed projects.

These are the other places related to KerberosSDR/KrakenSDR:

https://www.rtl-sdr.com/forum/viewforum.php?f=9&sid=90f27fc0...

https://www.facebook.com/groups/235979877597815/

https://www.rtl-sdr.com/tag/krakensdr/

Very excited to hear things are moving!

To me the most interesting part of the paper was how they synchronize the streams from multiple receivers (they inject a common noise signal to all receivers and then align the individual streams using cross-correlation).

> It was also observed that the relative phases of the signal streams drift slowly during the operation.

This is an interesting observation. If they are running all RF PLLs from a common reference clock, and the PLLs remain locked, there shouldn't be any long-term drift.

Years ago I saw an interview with the guy who founded this website. It was at some ham meetup. I have looked around and can’t find that interview anymore. It was originally on YouTube… does anyone know the video I’m talking about? He specifically talks about learning that you can do anything you put your mind to after his MIT Phd.

Carl's PhD is from the University of Auckland.

Great work. Back when I worked on DFing, ESPRIT was my favorite estimation algorithm. If I remember right, it was slightly less accurate but much more efficient than MUSIC.