41–50 of 66 posts
There will be a few false positives from farmers coming to work the fields by our road, or people looking to hike in the nearby forests, etc. but it could be pretty fun nonetheless!
I read a lot about passive radars trying to leech off of opportunistic waves, and lots about actual troops preferring to play hide-and-seem with anti-radiation weapons just to use active machines. A config that strikes me as obvious but doesn’t seem to be popular would be just bistatic where you fire your own transmitter far away from yourself? There’s got to be a reason, but it seems like best of both worlds.
Multistatic radars (of which bistatic are just the case with N=2) are like the nuclear fusion of radar systems: everybody agrees it would be neat to have them, but they're always 20-30 years in the future. In practice it is extremely difficult to maintain the precise timing synchronization required for radar systems. Especially when used in moving vehicles or in sparsely populated areas the expected error goes WAY up…
I will actually concur with one of the less upvoted comments here: the most fascinating thing about this article is the website. I've seen that pattern on HN a couple of times in the past couple of months. It's an incredibly specific vanity domain called passiveradar.com. Who would want that unless they're a radar manufacturer or an expert in the field? In both cases, they would put their name on it, but there's no a…
(Not so) funny enough - I just did the same thing for https://gunsight.com complete with Claude generated interactive simulations for ballistics. We are actually building radars, and are likely going to use the domain in the future, but with zero effort I transformed an otherwise parked domain into something with a minimal amount of utility. So I do recognize the pattern.
I want this, but I do not have the experience with radio signals to build this myself without more guidance. Is there a DIY proof of concept I could lean on? How much more challenging will this be if you are in an area with overlapping FM signals from 2 transmitters sending the same signal?
Halfway in the video he mentions the MIT (or Stanford) course of a professor who recently died. That course is online and has a lot of documentation (much better than this course.
Build Your Own Drone Tracking Radar: Part 1 https://www.youtube.com/watch?v=igrN_wd_g74&t=292s
You can contact me if you want more guidance. For passive radar you can just start with recorded data. I have access to huge amount of recordings on the Ukraine battlefield. Buying or building cheap antennas and radios is not needed for passive radar software development.
Radar was developed during the last two years of WOII, mainly in Boston at MIT and hundreds of companies each building a radar, most were deployed months later to win the war. Development after the war shifted to Silicon Valley, founding Silicon valley and the later chip and software startups decades later.
Earlier quoted context omitted.
That's very evil to recommend a graduate electrodynamics book to learn more about passive radar. I would suggest taking a look at Platos Republic to get some intuition on why that is.
If you want to make an apple pie from scratch, first you must invent the universe…
Carl also references Plato's Republic when visiting the actual cave where Plato lived.
Carl also references books classical mechanics but not the book the parent comment mentions but earlier ones like Al-Baghdadi, Cristian Huygens, Galileo, Newton.
I am searching for (part-time) business partners who want to pursue a grant (or find a customer) to develop and build a passive radar system. We know of such grants and customers, we need motivated people to help us get the grant. It is mostly a computational software problem that needs a cheap supercomputer, we believe we are experts at that [1]. We already have two test area's where we are not restricted by laws: t…
Regarding passive radar it is nice system in theory. In practical setup it’s not mobile and location bound. Every location has different RF radiation environment. Since transmission is not controlled the reception (and detection) can’t be optimized for anything.
I am searching for (part-time) business partners who want to pursue a grant (or find a customer) to develop and build a passive radar system. We know of such grants and customers, we need motivated people to help us get the grant. It is mostly a computational software problem that needs a cheap supercomputer, we believe we are experts at that [1]. We already have two test area's where we are not restricted by laws: t…
There is no rocket science here. Every radar has at least one midrange FPGA inside. Every small radar company at least two FPGA devs like me to minimize bus factor. Regarding passive radar it is nice system in theory. In practical setup it’s not mobile and location bound. Every location has different RF radiation environment. Since transmission is not controlled the reception (and detection) can’t be optimized for an…
I showed your comment to the 20 year old drone detection experts in Ukraine and they laughed at your dismissal, I imagine these guys know a lot more about FPGAs (slide 12 and further of [1]) then you, their lives depend on it every day.
Actual passive radar as we do in the Ukraine kill zones is very difficult science because all radio sources move all the time and the entire environment is full of reflections of moving leaves, nets, etc. Plus multiple moving antennas and jammers.
But then the rewards are big too. At the moment 80% of Russian casualties are from fiber optic FPV or cheaper radio controlled FPV drones only. So if we get even a little passive radar working (mainly by better over the network nanosecond time calibration [1] and orders of magnitude cheaper software defined radio receivers scattered densely on the ground plus cheap decoy transmitters and jammers) we save hundreds of thousands of lives, even tip the balance in winning this war.
Key is the orders of magnitude more complex calculations we do, hence the need for cheap supercomputers (cheaper than NVDIA). The first supercomputer I sold in 1986 to a Phd working on radar at Holland Signaal, the military brach of Philips.
[1] White Rabbit - High precision clock distribution in modern astroparticle experiments https://indico.kit.edu/event/22/contributions/927/attachment...
[2] New timing system for the LOFAR2.0 telescope https://videos.cern.ch/record/3015600
[3] Rocket Science is no rocket science if you get my thrust https://theconversation.com/rocket-science-isnt-rocket-scien...
p.s. Btw, rocket science [3] is the wrong term because that is actually really not very hard science at all, never was. "Elon Musk set back space travel 50 years" - Alan Kay. (He means rocket science is the wrong science for space travel, you need much better propulsion than chemical rockets because of the Tsiolkovsky rocket equation.