While INS is not simple, it's also not that difficult to implement. As even the cheapest drones that can hover show new MEMS sensors are accurate enough to work with a proper filtering.
I did some prototype INS system as my master's thesis 10 years ago, the code was quick and dirty and even then the accuracy was like 30 meters after an hour of walking around with the device.
That is surprising, you must have had an extremely accurate accelerometer and gyro, or employed tricks [1]. There are two problems with determining position from acceleration measurements:
1. You're integrating twice (acceleration to obtain velocity, then velocity to obtain position). So if you have any noise or error, you're integrating that, and integrate that again. Hello, parabola.
2. Gravity. It's strong. So you have to subtract it (as it induces an apparent acceleration upwards).
If the difference between actual down and where your model thinks is down is just a fraction of a degree, you'll be totally off within minutes.
> As a concrete example consider a tilt error of just 0.05 [degrees]. This error will cause a component of the acceleration due to gravity with magnitude 0.0086 m/s2 to be projected onto the horizontal axes. This residual bias causes an error in the horizontal position which grows quadratically to 7.7 m after only 30 seconds [and thus to 770 m after 5 minutes, unless I'm mistaken, and 110 km after an hour]
[1] such as assuming that your foot has velocity zero while on the ground, which does not hold when you're in an elevator, for example, and which you can't use in a drone without some serious sensor fusion.
I had 2 tricks - really high-order filter borrowed from some paper and the assumption that a walking human doesn't gain constant acceleration. Even in an elevator you stop on a floor which resets your speed to 0.
I agree that there is no way you could extend this directly for flying, but with modern devices and things like ground-distance radar, relative airspeed indicators and so on I don't think it is beyond the realm of possibility. Plus we have detailed hightmap of the world, which, when combined with a radar should allow for terrain tracking. That makes the accuracy of sole INS much less crucial.
Thing is, it has to work over atlantic/pacific/cross north pole routes, etc. We're talking multiple hours and long distance, possibly with a lot of turbulence (even for GA, which actually gets less steady flight so...).
And then it needs to provide guarantees about said navigation, guarantees that those drones do not need.
> "lock-free algorithms" is a misnomer, you still have synchronization,
Lock-free doesn't mean that there is no synchronization. It is a way to synchronize memory access between threads from the start. It means that there is no additional locking to protect access to the shared resource - all read access is valid, from any number of simultaneous write accesses at least one succeeds (which is not true for some other algorithms like network exponential backoff).
Even on x86 the most common instruction you use is LOCK cmpxchg.
I don't know about the US, but in the EU regulators DID step in and limited amount of ozone that can be produced by consumer devices to relatively safe levels. It will smell like thunderstorm but shouldn't be too toxic.
I don't think you can smell ozone - it's rather noxious. I think what you can smell as "thunderstorm" is the air cleaned a bit by ozone and the process of ionization (which traps some bigger particles).
If you do the forestry right you create many plots in there and aim to cut down e.g. 2% in a given year. That mean you will get the whole forest replaced in 50 years. If you're careful to not cut too much in a single space then the animals and plants can move around and it should be ok for biodiversity.
Now for the energetic biomass - this is more like 5-10 year rotation so while the animals can move around the plants can't. Those will be mono-cultures to sustain energy demand until we have enough of some other energy sources.
Compare that to a strip mine and it is way smaller horror.
It can create place to live for animals, it can reduce particulates in the air. It's not a normal long-living forest that is grown for wood for 80-100+ years but it's still way better than burning coal.
Nuclear is good. Wood is carbon-neutral. We should use both to move ASAP from gas and coal. Especially that wood is easier to use in some existing coal furnaces.
And if you think that burning wood is carbon-spewing, then thin about what happens in all those forests once the trees age - they either get logged and used for construction, afterwords they get discarded and rot or they don't get logged, collapse and rot. Either way carbon is getting back into the air as CO2.
This is true on the scale of decades, but the problem with climate change is we don't need carbon neutrality for O(50 years). We need carbon neutrality today.
Yes maybe those forests would eventually release carbon in 2050 is all well and good, but very likely we'll have total clean tech solutions by then anyway. In contrast we only have a short window to reduce atmospheric carbon substantially to prevent significant warming by the end of the century. To the extent possible if we can keep carbon sequestered today and pay by having it released in 30 years that's a very good deal. Because it stops the runaway warming today, and it gives us three decades of investment to start sequestering atmospheric carbon.
But now a lot of infrastructure runs on coal. You can use wood instead and have this carbon captured and reused in the next 10 years or you can still burn coal while awaiting a perfect solution.
We have surplus of farmland due to farm efficiency. We have more forests in EU now than we had 10 years ago. Switching to biomass is a good step because every ton of wood that emits CO2 that will be recycled is better than 0.6-0.8 ton coal that gets burned now and adds carbon.
Good furnace produce little particulate emission so its almost on par with burning gas.
Biomass - so mostly wood, wicker or straw has all its carbon content coming from the air - they capture CO2 as they grow, when you burn them you release exactly the same amount of CO2, hence they're carbon-neutral.
If you just burn all the forests an be done with it it's a bad idea. But if you replant the forests with fast growing species you can cut them down every 5-10 years and have a lot of biomass to burn in basically a closed cycle.
> Copy the login screen of original laptop on a brand new laptop, and have it log the password when the victim types it to you over wifi.
This is why you need mutual authentication. The easiest is with 2 passwords. You enter a password, this authenticates you to the system. Now system presents you some secret. It may be a passphrase, something not obvious like a password prompt with a typo, or a splash screen with some pixels a bit off that are visible at the right angle. Something that a casual shoulder-surfing won't gather. Only when the system is authenticated to you then you enter the 2nd password o actually unlock the filesystem.
As for "identical replacement" of a system - good luck. A bit of glitter and nail polish on screws and it will cost a fortune to do so. If you have those capabilities you probably have the capabilities to "nicely ask me for the password".
We used glitter glue on ports for certain traveling individuals. Took pictures of the hardened glue. Very hard for a maid to replicate, be it evil or really good.
If someone is considering an "evil maid" style attack, the objective is to compromise your security without you knowing (so that you will continue using the device believing it is still secure). "Asking nicely" isn't going to accomplish that.
I did some prototype INS system as my master's thesis 10 years ago, the code was quick and dirty and even then the accuracy was like 30 meters after an hour of walking around with the device.