Interesting, I thought I read somewhere that they were, and the map from Dan with the blank areas seemed to support that. But I stand corrected.. which raises the question, why would a "global" positioning system have blanks on it??
I do question that map as I've had no problems with GPS in the part of India showing an area of "poor coverage" I'm also pretty sure Hawaii is in one of the depicted "poor coverage" zones as well, and I've had no issues there. Likewise, Cape Horn, the southern tip of South America gave me no trouble with GPS.Nope. GPS coverage is not completely global. The various maps I find differ a bit, but the coverages look similar to this:
Some of the mid-latitude ocean should be OK but WAAS would be inop. It's the poles that don't appear to be covered well.
Probably, for at least a while. I don't know how for out a spacecraft would go before there insufficient variation in reception times to calculate a good position. When there were fewer GPS satellites, sometimes the visible satellites would be in a geometry where there wasn't enough difference in timing to calculate a good solution.
I shall validate your Earth science, for I am a geologist. You are correct. To really nerd out:. The sea floor rock, being ultra mafic, (high in Fe+) has crystals of Magnatite that align with the poles while they grow during the cooling process at the divergent zones in the rifts.The poles flip about every million years, if I recall my university geology correctly. We are overdue for a change. There are concerns that the magnetic field may collapse for a while during the transition exposing us to hazardous 'cosmic rays'.
As I understand it no one really knows how the field arises or what causes the flips.
Pole reversal is the "conclusive" evidence for seafloor spreading which is a key mechanism in the movement of the continental plates. I can roughly recall the Atlantic case.
The US and Europe are slowly getting further apart. There is a volcanic ridge runs down the middle of the Atlantic. As continents move apart the molten rock comes out the slot and solidifies filling the gap. It takes on the local magnetic field as it does so.
There are consequent bands of opposing polarity baked into the rocks across the Atlantic ocean. This was found round about the '60s when Magnetic Anomaly Detectors became available. The MADs may have been developed for detecting submerged submarines and/or for oil exploration.
Lockheed Orion with MAD boom.
Theory of Plate Tectonics.
Continental Drift.
Gondwanaland.
Most of the above is likely mostly OK.
There is no connection to the accumulation of the greenhouse gas CO2 in the atmosphere.
http://www.phy6.org/earthmag/reversal.htm
But it is a flat turtle
Nope. GPS coverage is not completely global. The various maps I find differ a bit, but the coverages look similar to this:
Some of the mid-latitude ocean should be OK but WAAS would be inop. It's the poles that don't appear to be covered well.
Only on 285 and they're just a suggestionHere in Atlanta we have digital speed limit signs on I285 (not sure about 75 and 85), and they change depending on the traffic. Don't really need an LED screen per se.
The poles flip about every million years, if I recall my university geology correctly. We are overdue for a change. There are concerns that the magnetic field may collapse for a while during the transition exposing us to hazardous 'cosmic rays'.
As I understand it no one really knows how the field arises or what causes the flips.
Pole reversal is the "conclusive" evidence for seafloor spreading which is a key mechanism in the movement of the continental plates. I can roughly recall the Atlantic case.
The US and Europe are slowly getting further apart. There is a volcanic ridge runs down the middle of the Atlantic. As continents move apart the molten rock comes out the slot and solidifies filling the gap. It takes on the local magnetic field as it does so.
There are consequent bands of opposing polarity baked into the rocks across the Atlantic ocean. This was found round about the '60s when Magnetic Anomaly Detectors became available. The MADs may have been developed for detecting submerged submarines and/or for oil exploration.
Lockheed Orion with MAD boom.
Theory of Plate Tectonics.
Continental Drift.
Gondwanaland.
Most of the above is likely mostly OK.
There is no connection to the accumulation of the greenhouse gas CO2 in the atmosphere.
http://www.phy6.org/earthmag/reversal.htm
My cousin worked on the radio and navigational systems on the B52 until recently and he said it was just a few years ago they got rid of the sextant on board! Maybe they better go grab em back!
For me once off flying on my own again, took a few year hiatus and am now getting my TW endorsement for my "new" plane, I plan on doing much of my traveling with paper maps and reading water towers- just because its fun and keeps you more engaged than flying the magenta line. I'm not saying I wont ever bring foreflight with me, but there is a time to read water towers and fly train tracks too. I find real enjoyment in doing things without all the tech aids... Well I guess thats why I purposefully bought a 40's era rig with no modern navigational updates. Though I'm hoping the compass keeps working-that would still be nice to use
For the uninitiated the cartoon in post #69 is from xkcd.
https://www.xkcd.com/2098/
"A webcomic of romance, sarcasm, math, and language."
Here is one of my favourites.
https://xkcd.com/386/
Imagine how confusing that would be...
