Turning Every Radio into a Radar

> For network operators, it raises a different question: could the infrastructure that already generates subscriber revenue also generate a second, sensing-based revenue stream?

Are there people who experience positive emotions in reaction to sentences like these? I just… even in my days when I thought social good came from states/organizations downward rather than from humans upward… even then, when I thought a God’s-eye view was achievable, that more and better measurable data were the way to get there, and that the main barrier to effective social regulation was poor legibility… I feel like even then this would ring craven and avaricious to me.

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.

This is not new as the article claims: Passive radars using FM broadcast and 2G GSM were used in the 1990s Yugoslav war.