Close.

Carrier tracking does not require a very precise model of the earth. Real Time Kinnematic GPS has been done for well over a decade with rather sane processing requirements. It also isn't unstable. So long as the L1 and L2 signal of five satellites are tracked one can initialize on the fly, and you only need to track four continuously to maintain said initialization.

Like differential (a code-base correction) kinnematic requires a base receiver and a rover receiver. They can either be in real time contact or the results can be post-processed. Differential and kinnematic both work by estimating the ionospheric delays, the difference is between tracking the long-period time code or tracking the short-period (19cm) carrier wave.

The problem isn't the GPS system. The problem is John Deere is trying to use the system at an accuracy (100% availability at 1m) greater than the specified [civilian] performance levels (95% availability at 7m).

While I can't speak as to the John Deere system in particular, most the Ag navigation systems are using WAAS on the low end and VRS RTK subscription systems on the high end.

Here in Ohio ODOT offers a reduced-fee reduced-accuracy VRS option for farmers, who don't need the sub-cm service.

They either had an asset over the drone or the US totally fucked up in the GPS antenna design.

GPS signals aren't in the "directional" frequencies. If they spoofed from orbit we'd know.

Not saying we'd publish, but we'd know. We'd not only know they could, we'd know where in what orbit their spoofing bird was.

Is letting that cat out of the bag worth one drone?

I'm guessing it was an implementation blunder.

I don't want to believe the Iranians have a GPS spoofing system so advanced it can migrate a GPS-initialized inertial system from a good solution to a spoofed solution.

I, therefore, rather suspect they jammed GPS long enough for the bird's INS to lose initialization, and then introduced a spoofed solution. I call this an implementation blunder because if this form of attack had been predicted one would respond in a "safe" manner to loss of GPS.

Question, though, is where was their spoofing equipment? Off-the-shelf GPS antennas from Trimble have quite good radio-absorbing ground planes. This is used to prevent GPS multipath when working near the ground, but would be quite effective at rejecting terrestrial transmission of false GPS signals. Does this mean Iran had one or more airplanes flying over the drone? Interesting, interesting.

Seriously - what are the chances of these chemicals migrating upward through a couple miles of solid rock?

Chances of migration through rock? 0%.

Chances of migration past an improperly grouted drill pipe? 100%.

If everyone cemented their well properly there wouldn't be 1/100th the problem there is.

Most likely you cleared album art (as the poster above mentioned) or your tagger was set to remove padding.

With ID3 tags residing at the start of the file it is common to pad the tags with blank space so that future (longer) edits don't necessitate the rewriting of the entire file. Too Many shitty taggers remove padding by default.

Wireless docking for your mobile device, when combined with inductive power. No more cables.

You going to rectify that?

First the machines were better than me at math.
Now the machines are better than me at emotions?

Actually, take that back. The VAX I used in college was probably better at reading emotion than me.

It's in groupon's interest to not let the client do that. They get vast sums of money from these "deals" and they know the system doesn't do the small business any good, because the couponers are pretty much all piss taking free loaders.

Not only does Groupon allow businesses to set a limit, it very clearly is in Groupon's best interest to do so.
If Groupon partners overextend themselves and deliver shitty service nobody will use Groupon.

One way or another you're going to have to get the drones/station to the satellites. You're going to have to have *something* pull up next to the satellite and either drag it into a reclamation bay or have the whole reprocessing unit go up right next to it

Except that moving the birds from their widely differing orbits is a major expense.

I don't think we could do it until we have electrically-powered engines that can be recharged with solar power and a rather large, permanently-manned space station.

Ion drives exist. But like all things in life there is a tradeoff. Engines which don't hurl much mass don't produce much thrust. Engines which hurl lots of mass require lots of propellent, be it electrically accelerated propellant or chemically accelerated propellant.

Not to mention that since they already bought the drives they are selling now, the price hikes are gouging.

That's not how pricing works.

How much accumulation does the "runway" see in a year? I would think a glideslope would be easy to install, and could be adjusted up as the ice/snow increases. I would also think a localizer would be possible as well. But, then again, I'm not sure my brain can fathom what a -70 environment is like.
 

It is analog film. You measure resolution by the level of detail and the smallest objects you can make out.

No, you measure film resolution in lp/mm.

While you are correct as to what the stated goal in TFA was, I think OP has an interesting insight.

Much as in firearm forensics where there are shell casing / bullet marks characteristic of both the product line as a whole and of the specific firearm I have little doubt PUFs would be able to identify not just a unique chip, but also what model it is.