It's quite advanced and there are all kinds of different techniques that work, e.g. wavelet analysis, topological data analysis, deep learning, etc. Not much in

It's quite advanced and there are all kinds of different techniques that work, e.g. wavelet analysis, topological data analysis, deep learning, etc. Not much info on deployed applications, of course, not that I could find. Some keywords for Google Scholar: "Passive localization", "mm-wave antenna array", "device free localization", etc. I collected a few relevant articles in this comment here: https://news.ycombinator.com/item?id=22480444 https://news.ycombinator.com/item?id=22480444 But I'm afraid every time I look there are more I haven't seen before, using different variations on the lingo, such as "passive sensing" and all kinds of different stuff. Here's a video that really drives it home for me: https://www.youtube.com/watch?v=kBFMsY5ZP0o https://www.youtube.com/watch?v=kBFMsY5ZP0o