"HawkEye’s current constellation of 21 satellites is trained to locate the sources of electromagnetic emissions with wavelengths ranging from roughly 2 meters down to 2 centimeters, with “Signals of Interest” including satellite phones, walkie-talkies, cellular towers, and GPS."
Despite the headline, the system does NOT track individual cellphones or GPS receivers. Cellular signal from a personal cellphone isn't strong enough to register at satellite altitude. The same goes for non-milspec walkie-talkies.
"That is impossible" is literally the bread and butter of signals intelligence.
Measuring light bouncing off a window to hear conversations, using millimeter waves to see through walls, taking photos from space, and planes that could fly themselves were all the realm of science fiction at one point - while in the hands of intelligence agencies.
Still, the whole "this is what we have imagine what the gov has" is usually wayyy overrated of a take and IRL it's usually way more boring and incremental, closely tracking commercial industry.
In most cases it's their ability to spend money to build large teams to employ tech, the complete scale of operations (XKeyscore+TEMPEST comes to mind), and the care they take is where things like the NSA dominate vs the average ability of the best hacker. Their unique advantages are only rarely in the individual technological leaps, which either a) industry has no match of or b) well informed technical experts are unaware of, like the things you reference.
FWIW you almost certainly can at minimum generalize the location of a phone if you know roughly where to look via beamforming [0]
Massive antenna arrays and SIGINT satellites have massive funding and decades of history, and they've already shown interest in tracking literally everything else [1]
This isn't some star trek type of thing, this is a "would the USG dump enough money into SIGINT to implement it?"
I'm very confident the technology exists to roughly track specific locations of interest for specific devices if not more.
I understand people may disagree but it would be foolish to assume it's beyond the realm of possiblity.
Amateur radio operators with just a moderate bit of gain (small uda-yagi antenna or the like) uplink to LEO satellites with ~5 watts all the time. At peak power a cell phone can be about 3 watts... but their antennas are not directional. So that loss of ~8dB of antenna gain has to be made up by increasing the sensitivity or gain of the satellites in LEO by increasing antena aperture or better front end low noise amplifiers. It's all very feasible given the clear line of sight.
What's less feasible is having enough of these at good positions overhead of a single cell phone to multi-laterate it's position using shared timestamps on the downlinked spectrum from multiple satellites.
I think it's entirely feasible with the budget of a medium space services corporation that can launch 21 satellites.
I can easily communicate with LEO satellites with a normal HT and a bit of gain on the antenna. It stands to reason that with better sensitivity receivers you would be able to pick up cell phones pretty easily, though identifying specific units is likely not yet possible.
Depends on the satellite and the altitude. SpaceX/Starlink have claimed their new satellites (in LEO) will be able to provide limited service to existing and unmodified mobile phones with a view of the sky.
Civilian GPS receivers are passive reception devices.
> Cellular signal from a personal cellphone isn't strong enough to register at satellite altitude.
This isn't entirely true. A primary limiting factor is the frequency-specific gain of satellites' antenna arrays. With a big enough antenna and fast and sensitive enough ADCs, much more is possible. Sifting through TD-SCDMA is the fun part.
Both of you guys are half right, Starlink does not currently talk to iPhones, but it will be able to as Starlink Direct is intended to appear as a regular mobile tower. The emergency satellite SOS feature on iPhones is with another constellation.
Despite the headline, the system does NOT track individual cellphones or GPS receivers. Cellular signal from a personal cellphone isn't strong enough to register at satellite altitude. The same goes for non-milspec walkie-talkies.