Hacker News

points by wildzzz 6 hours ago | 0 comments

Someone presented a passive radar system using an RTLSDR receiving TV broadcasts reflected off of nearby planes at a 2017 GNURadio conference. If amateurs can do it, you can bet the military has already designed, built, tested, deployed, and retired a similar system.

This isn't exactly a new subject, the same concept powered the first radar guided missiles in the 1940s (enemy is illuminated by a ground or airborne radar, missile tracks the reflection).

I'm fairly certain I've already read an article in an IEEE magazine talking about this topic (passive radar via cell towers) a few years ago.

[–] rpcope1 2 hours ago

KerberosSDR and later KrakenSDR are precisely this, and the guy behind it got a spanking after putting up a passive radar implementation that actually works ok publicly on GitHub sometime in the pre-AI era. Supposedly it was considered an ITAR issue, but the similar MLAT capability instead of phase coherent sensing like you get with a Kraken is basically deployed everywhere today (all of the ADS-B nodes that feel FlightAware, FlightRadar, etc.) It's certainly not novel and not in the way TFA wants to paint it.

[–] kooi 4 hours ago

I interviewed at company and their project was applying the music algorithm to find covert radio transmitters.

They were direct sampling the RF signals and running them through a bunch of H100's to get the algorithm to operate near real time. (They were quite proud of their 20 or so H100's)

Maybe this post is about that? It really lacks any technical substance. A bunch of corpo-talk is your ask me.

They probably throw all the signals, phase information into a ML model. But likely think the model inputs are very proprietary information so they just say ~ML will solve it~.

https://en.wikipedia.org/wiki/MUSIC_(algorithm)