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GPS positioning systems.


Handy andy

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Ionosphere delays can be measured and compensated for if you have two frequencies at your disposal, since there is dispersion (the effect depends on frequency). It's the troposphere that has to be approximated.

If you have a very good dual frequency GPS receiver you can extract column water vapour content.

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Where did you get the idea that argon is radioactive?

 

Sorry senior moment, radon gas, is radioactive.

 

My mind was on several things one being ref the Bermuda Triangle, and gas leaking from the sea bed, that might be radioactive and cause radio signals to be blocked, which then lead me to wonder if radio active gas or massive amounts of radiation after a nuclear bomb might block satellite signals. High altitude nuclear weapons are not really related to understanding GPS, but the EM pulse could ionize enough air to block satellite signals. Inter continental missiles if using GPS could get lost if they lose the satellite signal.

 

 

The troposphere is the lowest layer, at the lowest altitude and highest pressure.

 

Thanks for the correction.

Edited by Handy andy
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I wouldn't get too hung up on modern myths.

 

Bermuda myths aren't modern myths and not really the gps thread, BUT :) my wife was single handing her yacht through the Bermuda Triangle 40 years or so ago, (before it was fashionable for ladies to single hand yachts across oceans) and observed a large amount of small bubbles coming out of the ocean surface. Imagine what would happen if gas trapped on the ocean floor, was dislodged by an earth quake, and came up all at once in large quantities, a ship might just fall down a hole in the ocean, an airplane might fall out of the sky. If it was radioactive gas, it might cause some upset of instruments etc. :)

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There is no such thing as "the Bermuda triangle". It is a combination of selection bias and pure fabrication.

 

We seem to be drifting off thread, but there was no such thing as super waves reported by mariners until scientists discovered them. :) The radon gas idea being released from the sea bed was put forward as an explanation for the loss off shipping in the Bermuda triangle some years ago. Another theory possibly less believable, I heard from a Moslem waiter I spoke too in Indonesia was it was the gate to hell, or so he had been reliably informed :) The guy considered himself to be quite liberal and drank beer in his own house, things got a little strange when bacon was mentioned, luckily we had eaten by then.

 

Back to the thread and weakened or loss of gps signal due to ionisation of the atmosphere, or radiation due to EM pulse from high altitude nuclear explosions. Radiation from a nuclear blast will work similar to the suns radiation.

 

The air is easier to ionize at higher altitude, because it has less chance to recombine, according to collision theory, it is also very cold, which should make it harder to ionize. The air is normally easier to ionize when it is hot. Do air molecules at higher altitude have higher kinetic energy, than at lower altitude, making it easier to ionize them. Why are gps signals lost in ionized air. Is it partly because the signals are absorbed by the molecules or is it just a case that the signal can not be separated from the back ground noise. Oxygen absorbs a lot of EHF, at what frequencies does nitrogen absorb signals.

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The air is easier to ionize at higher altitude, because it has less chance to recombine, according to collision theory, it is also very cold, which should make it harder to ionize. The air is normally easier to ionize when it is hot. Do air molecules at higher altitude have higher kinetic energy, than at lower altitude, making it easier to ionize them. Why are gps signals lost in ionized air. Is it partly because the signals are absorbed by the molecules or is it just a case that the signal can not be separated from the back ground noise. Oxygen absorbs a lot of EHF, at what frequencies does nitrogen absorb signals.

 

 

The energy from temperature is a very small component. kT for room temperature is about 0.025 eV. Halving or doubling that is still a small number compared to the several eV necessary for ionization.

 

EM waves cause free charges to move. The energy for the motion comes from the EM wave, hence the amplitude is reduced.

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The energy from temperature is a very small component. kT for room temperature is about 0.025 eV. Halving or doubling that is still a small number compared to the several eV necessary for ionization.

 

EM waves cause free charges to move. The energy for the motion comes from the EM wave, hence the amplitude is reduced.

 

Does GPS transmit easily pass through positively ionized air with the electrons driven off after an EM pulse. How long does it take for the electrons to recombine, and emit photons, or radiation. If there is a deficiency of electrons in the air, the remaining positively charges atoms will become highly mobile and collide with other less charged atoms, causing them also to become ionized.

 

Water vapour in the air at around 2000C is mostly fully broken down into hydrogen and oxygen, H+ and O-, by heat, kinetic energy. Would the EM pulse drive the electrons away from the Oxygen. What is the rise time of an EM pulse and how much energy do they have. Is it this charge that is used to knock out Electronics using high altitude nuclear bombs. How does one go about calculating the amount of charge in or induced by the EM pulse. Does an EM pulse cause an avalanche effect as in a Plasma.

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What part of our atmosphere reaches 2000 ºC?

 

Gases when heated can reach 2000C water is mostly disassociated at this temperature but at 6000C it is completely disassociated. Plasma in lightning reaches temperatures far in excess of this. Lightning in the atmosphere causes temperatures in excess of 2000C and so would a nuclear bomb exploded in the upper atmosphere where the air is very thin and ions will take longer to recombine.

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This thread is sounding more and more like a chatbot - a series of not-quite-sequiturs picking up on random words in the previous post.

 

Exactly it has become uninteresting. I can read anything I want to know about GPS on wiki. If people aren't prepared to ask questions around the edge of what is common knowledge on wiki the thread is pointless.

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You've not answered Swansont's question with anything relevant to the question. It really could be a chat bot.

 

 

I did and it was deleted with a reprimand. I covered one or two things relating to another thread. Very naughty.

 

What in the atmosphere can reach 2000C, Nuclear explosions, Lightning, Volcanoes, Power Stations etc .

 

If you take the time to go back through the posts, you may realize I was not trying to cover what can be looked up in Wikipedia, and was trying to make the thread at least interesting for one (me).

 

I had played around focusing on time dilation and curved space, and then started looking at the ionosphere and things blocking the signal or how the signal could be lost either deliberately via high altitude explosions or naturally in thunderstorms etc. I was invited by swansont to start the thread, and have received a number of obtuse responses throughout. Stranges question above is an example. What the hell chat bot is meant to mean I have no idea, is it even a term in English. "Frankly my dear I don't give a damn". Strange as it may seem I don't believe time dilation is anything more than the result of the curvature of space, and is only the clock slowing down. I started a thread to this effect under speculations, which was based on time dilation space curvature and general relativity. Strange as it seems many people wanted to include Special relativity as part of an argument to state I was wrong. Which might well be the case.

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I did and it was deleted with a reprimand. I covered one or two things relating to another thread. Very naughty.

 

 

 

No posts have been removed from this thread, and I don't see any modnotes. Your two removed posts in this calendar month were in a different thread (off-topic for that discussion) and made no mention of GPS.

 

What in the atmosphere can reach 2000C, Nuclear explosions, Lightning, Volcanoes, Power Stations etc .

 

I'm pretty sure if you were using GPS in a nuclear blast area, the loss of a GPS signal would not be your primary concern.

 

Lightning is a very localized effect.

 

Volcanoes and power stations? No, I don't think so.

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No posts have been removed from this thread, and I don't see any modnotes. Your two removed posts in this calendar month were in a different thread (off-topic for that discussion) and made no mention of GPS.

 

I'm pretty sure if you were using GPS in a nuclear blast area, the loss of a GPS signal would not be your primary concern.

 

Lightning is a very localized effect.

 

Volcanoes and power stations? No, I don't think so.

 

Perhaps the post was not saved :) I do however have an email with a reprimand, which I assume the deletion was due to, I did not follow the link on the email.

 

I asked the question ref the EM pulse pushing electrons away, and asked the additional question ref signal propagation in positively ionized air, and further signal loss caused by electron recombination with ions, giving off radiation and interference.

 

I watched Krakatoa blow from 1/4 mile away, Volcanoes do lightning, as did Yasser in Vanuatu. Yasser gave the most awesome lightning display I have ever seen, Awesome in the true sense of the word. Getting out of the office opens the mind to the real world!

 

Even steam from steam engines is ionized, electrons recombining will give off radio waves or photons, as well as conducting current. Do these interfere with GPS signals as well as the other stuff mentioned above.

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No, you didn't.

YES I DID, I was anchored inside the old caldera rim about 4 years ago, (the caldera rim is remnants of what was not blown up in the original explosion), watching the new Krakatoa which is growing in the middle of the old caldera rim. It was smoking when I sailed in and anchored, after about an hour it exploded repeatedly for about 6 hours. The Child of krakatoa, or Anak krakatoa as the locals call it is very active. We anchored in a depth of 5 metres where it was charted at 25 metres, when we pulled our anchor up in the morning, the water around the boat was bubbling, and the anchor was too hot to touch. The whole sea bed is rising inside the rim. The new cone when we were there was approx 500m above sea level, and the ash and rocks blasted into the air I estimate went 1500m into the air above the volcano taking about 10seconds to reach the peak after every explosion. Awesome, you dont experience things like this by sitting at a computer.

 

So there! I did see it and you are wrong.

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So you saw Anak Krakaota erupt. That must have been impressive (I have spent many years living in earthquake/volcano zones in different parts of the world).

 

But what the hecking heck does it have to do with GPS? Why do you go off on these bizarre irrelevant tangents?

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YES I DID, I was anchored inside the old caldera rim about 4 years ago, (the caldera rim is remnants of what was not blown up in the original explosion), watching the new Krakatoa which is growing in the middle of the old caldera rim. It was smoking when I sailed in and anchored, after about an hour it exploded repeatedly for about 6 hours. The Child of krakatoa, or Anak krakatoa as the locals call it is very active.

 

 

Krakatoa went in 1883. Anyone 1/4 a mile away when it erupted died in the blast. Two reasons I know your original claim in not true.

 

You watched Anak Krakatoa erupt. As Strange observes, that must have been impressive. Your original statement is very misleading, which is the opposite of what you want to do in a science discussion.

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Krakatoa went in 1883. Anyone 1/4 a mile away when it erupted died in the blast. Two reasons I know your original claim in not true.

 

You watched Anak Krakatoa erupt. As Strange observes, that must have been impressive. Your original statement is very misleading, which is the opposite of what you want to do in a science discussion.

 

Krakatoa has erupted many times, famously in 1883, but has continued to erupt ever since. It is still known as Krakatoa, The cone which is appearing in the centre of the old caldera is still the original volcano over the original hot spot which has not moved. My original statement was correct, you assumed I was referring to the eruption or rather explosion of the island in 1883, which for sake of correctness is not to the east of Java it is to the west of Java. The island was not completely destroyed, 3 sections of the old caldera still stand, making a kind of lagoon around the new cone. The only part of my statement which was slightly wrong was I was there 7 or 8 years ago, not 4, time flies. To give an accurate fix of my location I was anchored inside the caldera rim on the south side, out of the ash plume.

So you saw Anak Krakaota erupt. That must have been impressive (I have spent many years living in earthquake/volcano zones in different parts of the world).

 

But what the hecking heck does it have to do with GPS? Why do you go off on these bizarre irrelevant tangents?

 

Tangents huh

 

I think I was going down the line of asking what could block or interfere with gps signals, and Swansont asked what heats the atmosphere to 2000C, Ref strange or bizarre ideas, I think that volcanoes are interesting, and if a super volcano was to throw tons of ash into the atmosphere, which could change the earths climate, the ash may also interfere with gps transmissions. Since you have lived around volcanoes before you will be aware that ash in the atmosphere produces much larger lightning strikes than a normal thunder storm with mainly only water droplets involved in the generation and holding of charge. The ash seems to hold more charge, it is possible that an ash cloud might work like the ionosphere and block signals, as might a nuclear winter after a war.

 

Since most things relating to GPS are covered on Wikipedia and to try and keep the thread interesting to at least one party, I thought I would look at the things not normally covered by Wikipedia. Hence my line of thought ref gps signal loss.

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