Cell Towers Can Double as Cheap Radar Systems for Ports and Harbors (2014)

More coverage of RF sensing, including laptops/phones with radios+NPU to sense their human:

2025, "Espargos: ESP32-based WiFi sensing array", 30 comments, https://news.ycombinator.com/item?id=43079023

2024, "How Wi-Fi sensing became usable to track people's movements", https://www.technologyreview.com/2024/02/27/1088154/wifi-sen...

2023, "What Is mmWave Radar?: Everything You Need to Know About FMCW", 30 comments, https://news.ycombinator.com/item?id=35312351

2022, "mmWave radar, you won't see it coming", 180 comments, https://news.ycombinator.com/item?id=30172647

2021, "The next big Wi-Fi standard is for sensing, not communication", 200 comments, https://news.ycombinator.com/item?id=29901587

Right. The longer range versions of multistatic radar are used to detect stealth aircraft.[1][2] All that careful stealth geometry to minimize direct reflections doesn't help much when the emitters and receivers are in different locations.

[1] https://www.presstv.ir/Detail/2024/11/18/737423/guardians-of...

[2] https://www.yiminzhang.com/pdf/radar13_passive.pdf

Well, you don't even need a radar. Tamara sensor could detect B-2, when it had it's onboard radar on.

https://en.wikipedia.org/wiki/Tamara_passive_sensor