3 ms·

Radio direction finding is reasonably straight-forward in theory, but practice is a challenging art. First, what frequency is the control transmitter on? (or f

Radio direction finding is reasonably straight-forward in theory, but practice is a challenging art. First, what frequency is the control transmitter on? (or frequency-band/freq-hopping in). If it is one of the usual R/C bands, then that is a limited search space. Or if the perp is not so concerned with observing frequency allocation treaties and regulations, well then now you have a big hunt. Second, what other signals are in that band? Suppose it is in the 2.4GHz ISM band. Given a spectrum analyzer plot of 300 spread-spectrum signals hopping in the ISM band, which 299 are WiFi and Bluetooth and other, and which is the perp? The microwave ovens are easy to distinguish, but still add clutter. So if you can pick on a single signal, then you can use Doppler techniques to get a rough bearing, and directional antennas to zero in. I suspect they had some crews working the problem, but it is a challenge. Anyone interested can look up Amateur Radio “fox hunting” in the US, and in Europe “radio orienteering” is popular. Since signal hunters are not transmitting, no license is required to participate in a hunt.

nasredin 8y ago
I know public reporting says US is behind Russia in EW. I don't know how good UK EW is, but if the UK can't locate commercial drones signals, than we are in trouble. (Fun fact, UK was very good in EW during WWII https://en.wikipedia.org/wiki/Battle_of_the_Beams https://en.wikipedia.org/wiki/Battle_of_the_Beams ) Military perspective on this: http://www.thedrive.com/the-war-zone/25608/rogue-drones-have-paralyzed-u-k-s-gatwick-airport-for-more-than-20-hours http://www.thedrive.com/the-war-zone/25608/rogue-drones-have...
rasz 8y ago
>pick on a single signal You dont have to do it manually. Nowadays you can grab whole 2.4-2.5 range(most common drone remote frequency), process it in real time, at 3 locations simultaneously, and produce signal position map with every transmitter inside the triangle or interest. Even amateur fox hunts can be automated to the point of trivializing whole thing with couple of those https://www.indiegogo.com/projects/kerberossdr-4x-coherent-rtl-sdr#/ https://www.indiegogo.com/projects/kerberossdr-4x-coherent-r... . More professional hardware does exist, quick search gave me http://spectrafold.com/quadrus/product/dru-244a-1-4-pci/ http://spectrafold.com/quadrus/product/dru-244a-1-4-pci/ so Im sure MIL already uses this instead of primitive manual techniques.

nasredin 8y ago

I know public reporting says US is behind Russia in EW. I don't know how good UK EW is, but if the UK can't locate commercial drones signals, than we are in trouble. (Fun fact, UK was very good in EW during WWII https://en.wikipedia.org/wiki/Battle_of_the_Beams https://en.wikipedia.org/wiki/Battle_of_the_Beams ) Military perspective on this: http://www.thedrive.com/the-war-zone/25608/rogue-drones-have-paralyzed-u-k-s-gatwick-airport-for-more-than-20-hours http://www.thedrive.com/the-war-zone/25608/rogue-drones-have...

rasz 8y ago

>pick on a single signal You dont have to do it manually. Nowadays you can grab whole 2.4-2.5 range(most common drone remote frequency), process it in real time, at 3 locations simultaneously, and produce signal position map with every transmitter inside the triangle or interest. Even amateur fox hunts can be automated to the point of trivializing whole thing with couple of those https://www.indiegogo.com/projects/kerberossdr-4x-coherent-rtl-sdr#/ https://www.indiegogo.com/projects/kerberossdr-4x-coherent-r... . More professional hardware does exist, quick search gave me http://spectrafold.com/quadrus/product/dru-244a-1-4-pci/ http://spectrafold.com/quadrus/product/dru-244a-1-4-pci/ so Im sure MIL already uses this instead of primitive manual techniques.