http://gpsworld.com/anti-jam-technology-demystifying-the-crp...
> CRPAs work by exploiting spatial diversity; that is, making use of the fact that the desired satellite signals, and the unwanted jamming signals, generally arrive from different directions. In simple terms, you create a spatial filter, one that removes signals that arrive from particular directions, whilst letting through signals from other directions. To achieve this, rather than use a single antenna, we use an array of antenna elements.
Off-the-shelf open source consumer drone flight controllers already have enough sensors to achieve what you suggest.
Celestial navigation by imaging the sky, and combining that data with a clock and compass.
You have issues with weather affecting coverage but it would be a lot cheaper than a massive ineffective wall.
https://en.wikipedia.org/wiki/Tethered_Aerostat_Radar_System
I expect the same effect for drug or people trafficking. While no barrier will stop everyone, and there are already drones and submarines designed for crossing well-protected borders, even fairly simple obstacles will stop or deter the majority of traffickers.
Now Trump might actually think it's a good idea - and I actually think he does - so that's absurd. But realistically it operates as a political beacon, and one that's quite effective.
One of many many reasons. While it's sufficient, it's far from the top of the list.
[0] https://motherboard.vice.com/en_us/article/neqvag/the-us-nav...
Furthermore even though these lasers are very cheap, by army norms, to fire, they're still 600$ or so for a single shot. So shooting down drones will be expensive. Far more expensive than the drones themselves.
Third. Defense against a laser is easy (a mirror, essentially, though you need to know the frequency to get an effective one). I must say that I don't know why you'd try to defend a drone. I'd try to hide it, since that's so easy.
And while a rules-based autopilot is easy to disrupt using jamming, a learned autopilot is essentially impossible to fool into crashing. Maybe you can divert it, I guess.
Not really, Where it matters, radars have been deployed that can easily find those things. I've seen live demonstrations in the mid 1980s (as in, a system protecting borders), and I bet the state of the art has advanced since then. IIRC it was a SAR system, but I'm not sure.
> Furthermore even though these lasers are very cheap, by army norms, to fire, they're still 600$ or so for a single shot. So shooting down drones will be expensive. Far more expensive than the drones themselves.
There are newer, weaker versions that are at ~$1/shot, that would still likely take down your average drone. Also, even $600 is not "far more" expensive than a modern drone that can carry things across the border; It is slightly more expensive, but (relatively speaking), super cheap and, since it is energy, fungible (that is, you don't spend it until you spend it, unlike e.g. missiles which have to be ready long beforehand)
> Defense against a laser is easy (a mirror, essentially, though you need to know the frequency to get an effective one). I must say that I don't know why you'd try to defend a drone. I'd try to hide it, since that's so easy.
That's the popular belief, but it is not actually true. A perfect mirror such as would be required would cost today significantly more than the drone itself, as in x10 to x100, if it is at all feasible (You can't have sharp edges, you likely need glass).
It is currently infeasible to mirror-cover missiles or rockets that cost a lot more than the drone, and the problems are (mostly) not about the projectile speed or heat.
> And while a rules-based autopilot is easy to disrupt using jamming, a learned autopilot is essentially impossible to fool into crashing. Maybe you can divert it, I guess.
Lasers can blind cameras even better than they do human eyes. What sensors is this autopilot going to depend on when it is vision and GPS blinded?
Yup, long stare SAR hooked up to a DVR was a thing over 10 years ago - it could cover a lot of ground (like a large Iraqi city) with a resolution that would easily detect this drone.
Not - one drone. A drone in the air 24/7 every 5km for a border ~2000 km long.
But even if you need a drone every 5km (you don't). That's all of 400 drones, 800 if you want to have pairs doing charge-work duty. For an 2000km border guarding operation, that's really not much. An order of magnitude or two cheaper than the fence they would guard.
That's probably worse than those drones watching from above, seeing as you'd need actual infrastructure at every interval. And, that'd be fixed infrastructure, with fixed blind spots.
Where are you getting that $600 number? The laser in the article quoted is 150kW, which firing for a fraction of a second would be no more than a few dollars electricity.
What is the approximate cost of allowing the drone in?
We just, as a society, have decided that the social cost is not worth it.
We gunless, pot smoking, socialized medicine, immigrant accepting countries are on the "outside".
I do say that with tongue in cheek.