Offline 3DGeek

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Re: Using airline flight data.
« Reply #340 on: September 04, 2017, 02:54:18 PM »
That post was already addressed. Here was my reply:

If any of those navigational systems use Latitude and Longitude then they are using a Round Earth coordinate system. It is difficult to imagine that Longitude and latitude is not used in any navigational system.

The only reply from the poster was a statement that Latitude and Longitude is correct. No evidence was provided for this statement. The only evidence in this thread are my sources showing that GPS provides incorrect distances. No sources have been provided show that any Round Earth navigational system provides correct distances. You and Frank continually refuse to provide evidence of such. There is nothing further to discuss on this matter.

Granted this is early in the discussion, but there is a very simple reason runners gps does not match course Distance. Course Distance is measured on the ideal line. Unless you are an elite runner at the front of the race free to choose exactly where you run, you do not run the ideal line. You take longer routes through corners, you can't run the straight line through an s curve in the road......
https://www.dcrainmaker.com/2009/03/racing-line-understanding-how-courses.html

That might matter a little - but much more likely is that known GPS errors are absolute distances (10 feet is commonly quoted).

Over a 200 foot race track - you'd get (perhaps) as much as a 10 foot error at the start line and another 10 foot error in the opposite direction at the finish - so the total distance (as measured by GPS) could easily be wrong by 10%.

But over a 3,000 mile airplane flight - you still only get a 10 foot error at start and end - so the percentage error is incredibly small.

Hence we can trust GPS measurements over long distances - but not so much over very short ones.

If you wish to use GPS for sporting events, you should use "Differential GPS" - which adds a special "Ground station" gizmo that acts as an additional "satellite" (in effect).  The GPS electronics can then measure positions accurately down to fractions of an inch RELATIVE TO that ground station.  You don't have any better precision over the entire world by doing that - but for sporting events, it produces the result you need.

But Tom's insistence on using this one scientific paper is indicative of desperation.   The content of the paper is utterly inapplicable to long distance measurements that we are discussing here.   We understand why standard GPS is hopelessly poor for things like sporting events - and can easily explain why those errors don't matter for airline flights...which is what we're actually talking about here.

Hey Tom:  What path do the photons take from the physical location of the sun to my eye at sunset?

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Online Pete Svarrior

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Re: Using airline flight data.
« Reply #341 on: September 04, 2017, 04:38:30 PM »
That would be a highly amusing position to take!  :-)

Should I make popcorn while you explain it?  I'm sure it'll be entertaining.
Have you considered the radical possibility that people will be more willing to co-operate with you if you don't attack them from the get-go? Why would I make the effort of explaining the world that surrounds you if:
  • You're 100% sure you've already got it figured out (it would be wasting your time)
  • You're completely disinterested in what I might have to say (it would be wasting my time)

There are plenty of people who are interested in serious conversation with me - why would I shift my busy schedule away from them and towards the likes of you?
« Last Edit: September 04, 2017, 04:52:11 PM by Pete Svarrior »
Read the FAQ before asking your question - chances are we've already addressed it.
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Re: Using airline flight data.
« Reply #342 on: September 04, 2017, 04:54:06 PM »
That would be a highly amusing position to take!  :-)

Should I make popcorn while you explain it?  I'm sure it'll be entertaining.
Have you considered the radical possibility that people will be more willing to co-operate with you if you don't attack them from the get-go? Why would I waste my time explaining the world that surrounds you if:
  • You're 100% sure you've already got it figured out (it would be wasting your time)
  • You're completely disinterested in what I might have to say (it would be wasting my time)

There are plenty of people who are interested in serious conversation with me - why would I shift my busy schedule away from them and towards the likes of you?

As this is a public forum, I think it'd be really worthwhile. There are many people out there in doubt about how the world looks like.

Besides that, since I registered to this forum, I haven't seen a single FE argument that made me think: "that's a really good point."

Re: Using airline flight data.
« Reply #343 on: September 04, 2017, 05:30:35 PM »
To be clear, GPS does not measure distances, it provides location data of known accuracy.  Applications will use that data to determine a distance using further data on the size and shape of the earth.

Note satnavs use details of individual roads to determine a route, duration and distance.

Offline Ga_x2

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Re: Using airline flight data.
« Reply #344 on: September 04, 2017, 06:45:25 PM »
That would be a highly amusing position to take!  :-)

Should I make popcorn while you explain it?  I'm sure it'll be entertaining.
Have you considered the radical possibility that people will be more willing to co-operate with you if you don't attack them from the get-go? Why would I make the effort of explaining the world that surrounds you if:
  • You're 100% sure you've already got it figured out (it would be wasting your time)
  • You're completely disinterested in what I might have to say (it would be wasting my time)

There are plenty of people who are interested in serious conversation with me - why would I shift my busy schedule away from them and towards the likes of you?
Actually I asked with no malice. And I doubled down by saying that you are clearly not an idiot ;D
So maybe you could like copy/ paste something or point me in the general direction of your views, thus avoiding misrepresentations by those eeevil roundies ;D

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Offline Tom Bishop

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Re: Using airline flight data.
« Reply #345 on: September 04, 2017, 09:23:35 PM »
But over a 3,000 mile airplane flight - you still only get a 10 foot error at start and end - so the percentage error is incredibly small.

Where has this been demonstrated?

Quote
But Tom's insistence on using this one scientific paper is indicative of desperation.   The content of the paper is utterly inapplicable to long distance measurements that we are discussing here.   We understand why standard GPS is hopelessly poor for things like sporting events - and can easily explain why those errors don't matter for airline flights...which is what we're actually talking about here.

I didn't bring up that paper as evidence, you guys did.

Re: Using airline flight data.
« Reply #346 on: September 04, 2017, 09:48:29 PM »
But over a 3,000 mile airplane flight - you still only get a 10 foot error at start and end - so the percentage error is incredibly small.

Where has this been demonstrated?

Quote
But Tom's insistence on using this one scientific paper is indicative of desperation.   The content of the paper is utterly inapplicable to long distance measurements that we are discussing here.   We understand why standard GPS is hopelessly poor for things like sporting events - and can easily explain why those errors don't matter for airline flights...which is what we're actually talking about here.

I didn't bring up that paper as evidence, you guys did.
Here is your opportunity.

Is timeanddate.com correct for you and what equipment are you needing to derermine the shape of the earth?

Re: Using airline flight data.
« Reply #347 on: September 07, 2017, 09:46:36 PM »
Why do I need to show you a map of the earth? What is wrong with the exact continental dimensions and distances being unknown?

Navigation, governance and commerce all break down if we don't actually know how far things are from each other.  It may seem trivial until you realize that international commerce relies on knowing exactly how far raw materials and finished goods have to travel before you purchase them on Amazon or at Walmart or whatever other physical/online store you use.  Your basic internet access only works because some poor schmuck dragged a specific length of fiber optic cable across the ocean to connect the land masses.  How else did you think that you could mildly irritate people in every time zone simultaneously?

In a modern world ruled by profit margin, knowing exact costs is king.

Thank you,

CriticalThinker

All that is known is how long the transportation takes. In Round Earth coordinate devices the distance is computed based on Round Earth coordinate geometry.
Well it seems I'm a few days late to this discussion, but wow this is fascinating! Up until today I honestly didn't realize some people still believe in a flat earth.

This particular thread fascinated me because my background is in avionics, and I'm also a pilot. So to me this whole flight time calculation exercise is a little silly, as it disregards how airspace systems work, how different navigation systems integrate in-flight to calculate flight times, air density... airspeed vs groundspeed etc..... and the speedometer vs gps thing was also interesting, ummm that one is quite easy to explain, if you've ever gotten out of a speeding ticket by getting your speedometer replaced you know what I mean 😉

So really I see flight times as a horrible way to prove or disprove um the shape of our planet.  Just curious, why so adamant about the shape of our planet being flat? Im honestly just a really curious person, which is why i sometimes end up in random corners of the internet, such as this, im not trying to disprove your theories, even though i recognize your argument to be faulty in this particular case.



Offline 3DGeek

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Re: Using airline flight data.
« Reply #348 on: September 07, 2017, 10:53:48 PM »
Well it seems I'm a few days late to this discussion, but wow this is fascinating! Up until today I honestly didn't realize some people still believe in a flat earth.

This particular thread fascinated me because my background is in avionics, and I'm also a pilot. So to me this whole flight time calculation exercise is a little silly, as it disregards how airspace systems work, how different navigation systems integrate in-flight to calculate flight times, air density... airspeed vs groundspeed etc..... and the speedometer vs gps thing was also interesting, ummm that one is quite easy to explain, if you've ever gotten out of a speeding ticket by getting your speedometer replaced you know what I mean 😉

So really I see flight times as a horrible way to prove or disprove um the shape of our planet.  Just curious, why so adamant about the shape of our planet being flat? Im honestly just a really curious person, which is why i sometimes end up in random corners of the internet, such as this, im not trying to disprove your theories, even though i recognize your argument to be faulty in this particular case.

Perhaps a brief summary of the argument so far.

1) If you look at either of the two "common" FE maps ("unipolar" and "bipolar") they both predict that the distance from (say) Sydney Australia to (say) Santiago Chile is between 2.1 and 3.4 times LARGER than it's known to be in the Round Earth world.    I point out that Qantas airlines have regular 747-400 flights between those two cities and it takes around 13 hours to fly those routes.   Since 747-400's cannot fly at Mach 2...these two maps must both be WILDLY incorrect.

2) There is some argument about "jet stream winds" - I point out that these winds can only speed up flights in one direction and Qantas flights times are only about 15 minutes different each way...this argument goes away (as it should!).

3) Tom Bishop asserts (rather bravely, I thought) that the FE'ers actually have NO IDEA what the map of the Earth looks like - the maps we see are just possible examples.

Wow!  That's a clever debate tactic.   By saying this, he believes that we can no longer use the "airline route distance/time" argument to defeat the flat earth.

Sadly, I'm quite a bit smarter than him...so I come up with this cunning argument:

4) Suppose we assume that the world *IS* flat - and we don't know the layout of the continents or anything.   If we know the distances between four cities that are widely spread - we can build a quadrilateral using the four distances along the sides.  Knowing the lengths of four sides and one diagonal (5 distances) - we can figure out the internal angles and basically know everything about that quadrilateral.

5)  If we now draw in the second diagonal, then it's length SHOULD match the sixth piece of distance data between the those cities...right?   Basic euclidean geometry.

6) HOWEVER: I look up the flight distances on the Qantas and British Airways web sited - we work through the math for couple of examples - and there is NO POSSIBLE flat quadrilateral that has those lengths those six distances simply do not form a quadrilateral with the given diagonals.   The error isn't small - if you pick the right sets of cities, the error is outrageous.

7) I would say that this is because our assumption that this is a PLANAR quadrilateral is incorrect (because the Earth is ROUND)..and if it's not planar then the distances we have are PROOF that the Earth cannot possibly be flat.   It might be concave or convex or some other shape - but it absolutely cannot be FLAT.

8) Notice that this is true no matter how the FE'ers draw their maps.   They simply cannot make maps that fit the airline flight data.

At this point - I'd claim victory...but the FE'ers aren't quite done yet.

9) Of course, the FE'ers first reaction to this is "Well how do we know that the airlines got those distances right?" - I demonstrate that various other web sites that calculate such distances...Google maps...all agree very well with the airline distances - but the FE'ers claim that ALL of our sources are simply using the same (in their view, incorrect) math.

10) In defense of the airlines flight distances - I point out that the flight times of these long routes are very well known - and the cruise speed of every airliner is well documented - and if we multiply flight time by cruise speed - we get very good agreement with the distances that the airlines claim.  This backs up my distances...if the flight times are correct and the speed an airplane can fly are correct then I've proved that the world isn't flat.

11) Now things start to get silly:  Tom Bishop (FE'er-in-chief) steps up and basically claims that the airlines AND the airplane manufacturers don't know how fast they can fly - so they fly a route with a stopwatch and set the time that way.   Does this argument sound kinda *desperate* to you?   It certainly does to me!

12) This is patent nonsense - the airplane manufacturers know how fast the plane will fly from data they collect from engine thrust curves, the drag on the airframe that's calculated from CAD data and double-checked in a wind-tunnel.   They cannot *POSSIBLY* think their planes have a top speed of 650 mph - when they are actually flying at Mach 2 on a daily basis!!

So, again, I say we have a win for the round earthers.

Then we get into the mire as Tom attempts to fling mud at things like GPS...when we know that airplane speeds are checked by the ATC radar, by LORAN, by all manner of other means.

Personally - I say this debate is won...the Flat Earthers no longer have a leg to stand on, and they should have the guts to admit it.

But they don't - and that's ALWAYS the case.   I've put up at least a half dozen SOLID arguments over the past month - and most of the time, they just stop posting to the thread when they no longer have a good come-back.

The world *IS* Round...it's not really debatable.
Hey Tom:  What path do the photons take from the physical location of the sun to my eye at sunset?

Offline Horhang

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Re: Using airline flight data.
« Reply #349 on: September 07, 2017, 11:30:26 PM »
3dGeek,
A thought occurred to me. To avoid all the fighting about calculated distance, simple use time as a proxy for Distance. Use hours as a base unit, and convert minutes to a decimal of the hour. Then use that as your distance between the cities. Should still get the same result I would think and it takes a hiding place, the distances are wrong, away because we know the times are correct.
Occurred to me because a lab I just did with my eight graders used measuring mass as a proxy for magnetic field strength with magnets on an electronic balance. Why not do the same thing here, use time as a proxy for distance?

Offline 3DGeek

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Re: Using airline flight data.
« Reply #350 on: September 08, 2017, 01:53:07 AM »
3dGeek,
A thought occurred to me. To avoid all the fighting about calculated distance, simple use time as a proxy for Distance. Use hours as a base unit, and convert minutes to a decimal of the hour. Then use that as your distance between the cities. Should still get the same result I would think and it takes a hiding place, the distances are wrong, away because we know the times are correct.
Occurred to me because a lab I just did with my eight graders used measuring mass as a proxy for magnetic field strength with magnets on an electronic balance. Why not do the same thing here, use time as a proxy for distance?

Yes, I essentially said that.  Not only must the airlines and plane makers be blissfully unaware of the actual speeds their planes are flying...but they must also be flying at different speeds on different routes...AND somehow "knowing" what speeds to fly at to make it APPEAR that the Earth is round instead of flat.

Not really plausible is it?

So the idea that the Earth is flat is clearly disproven...but do you think the flat earthers will admit defeat?  I'm betting not.
Hey Tom:  What path do the photons take from the physical location of the sun to my eye at sunset?

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Offline CriticalThinker

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Re: Using airline flight data.
« Reply #351 on: September 09, 2017, 03:31:41 PM »
No Tom,

In transportation distance matters as well.  Mileage is needed to ensure you don't run out of fuel and die.  Using the round earth coordinates to traverse both halves of the world or in your model both hemiplanes has yet to cause a large number of flights or ships to suddenly run out of fuel mid trip.

They would have known from previous trips and assessments of the Round Earth lat/lon readings how much fuel they would need to bring for xxx Round Earth miles.

If you travel 300 miles on a road trip, according to your GPS, and your tank is half empty you have an idea on how much fuel you need.

Quote
The miles of cabling that run under the ocean to connect the continents and create "the internet" had to be physically made and laid.  As did all of the continental cabling that connects California to New York, Paris to Krakow etc.  These are physical lengths of cabling that had to be manufactured and placed along carefully measured routes that just so happen, in your opinion, to match up perfectly with the Lat/long coordinates.

How do you know their methodology?

To answer your second question, because they had to apply for permits in all municipalities in order to establish the cabling lines in the first place.  When installing public infrastructure along roadways, each local government requires zoning approval in the form of schematics, materials properties, engineering assessments, environmental assessments etc which are all kept on public record.  When crossing national borders, the permitting process becomes even more complicated.  Ever wonder why road crews spend a lot of time with surveying equipment prior to a major road overhaul?  It's because in the event that they hit the buried cabling, water lines or gas lines bad things happen.  They have to accurately measure the roads and compare their measurements to the building permits on file to ensure that they don't blow up a city block or create a 2 foot high geyser or you know get any of their employees killed.  Almost all of the time, they're successful at this endeavor, so...

To address your first rebuttal.  Eh, no.  That's not how long distance air travel works.  When a new airplane design is created, they don't just load it up with people, launch it and hope no one dies along their maiden voyage so that they can track how much fuel they used for future flights.  It's not like running out of gas in a car where you can pull off the side of the road and wait for AAA to come by with a gas can.  An airplane would crash, people would die and most likely that company would be sued for wrongful deaths by family members of every passenger probably leading to bankruptcy.  Being as how this doesn't happen routinely, it's safe to conclude that they take distances based on the RE coordinate system, projected fuel performance as established during the design and modeling process and reasonable margins of error to ensure that they don't run out of fuel half way there.

You sound like you're getting desperate Tom.  Your arguments don't even make any sense anymore and you're purposefully avoiding discussing the real points of the argument.

Distance is measured, time is measured, speed is defined by those 2 measurements and can be measured as well.  When you know 2, you can solve for the 3rd.  Round earth model coordinate systems have routinely delivered people to their destinations for a long time.  The FE model doesn't even have an accurate measurable map to test navigation with. 

If the earth were truly flat, it would be simple to create a flat map with no distortion that accurately measures all of the continents and oceans.  This map doesn't exist, therefor reductio ad absurdum the earth can't possibly be flat.  Done.

Thank you,

Critical Thinker
Quod gratis asseritur, gratis negatur

Offline 3DGeek

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Re: Using airline flight data.
« Reply #352 on: September 09, 2017, 03:54:56 PM »
You sound like you're getting desperate Tom.  Your arguments don't even make any sense anymore and you're purposefully avoiding discussing the real points of the argument.

That is Tom's modus operandii.

You'll notice that if you start a thread about seeing things over the horizon where there are large stretches of water...then Tom will be on that thread, fighting every step of the way - quoting the idiot Rowbotham - citing 150 year old books...he's all over it.

When you start asking DIFFICULT questions, you'll get one or two very weak responses - then he'll go silent once the going gets tough.  He simply cannot grasp the inconsistencies in his claim that "light travels in straight lines" and his "alternative" theory of perspective...as if these are entirely separate matters rather than one being a consequence of the other.

In all serious debate - we rapidly run into the limits of his ability to understand the arguments being presented.

A man who was both intelligent and honest would be admitting that he was wrong at this point...but this is a guy who believes that you can easily cure cancer with "garlic and peppers" and that all people who served in the Navy are "murderers", that "Ebola can be  easily cured via Vitamin C injections.", "The treatment for HIV is Vitamin C"
 and that "There is a conspiracy in medicine."...just like NASA, I assume.

A couple of people here have said that he's the smartest defender of FET they have...that's a very sad statement.

Hey Tom:  What path do the photons take from the physical location of the sun to my eye at sunset?

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Offline TomInAustin

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Re: Using airline flight data.
« Reply #353 on: September 09, 2017, 11:12:37 PM »
You sound like you're getting desperate Tom.  Your arguments don't even make any sense anymore and you're purposefully avoiding discussing the real points of the argument.

That is Tom's modus operandii.

You'll notice that if you start a thread about seeing things over the horizon where there are large stretches of water...then Tom will be on that thread, fighting every step of the way - quoting the idiot Rowbotham - citing 150 year old books...he's all over it.

When you start asking DIFFICULT questions, you'll get one or two very weak responses - then he'll go silent once the going gets tough.  He simply cannot grasp the inconsistencies in his claim that "light travels in straight lines" and his "alternative" theory of perspective...as if these are entirely separate matters rather than one being a consequence of the other.

In all serious debate - we rapidly run into the limits of his ability to understand the arguments being presented.

A man who was both intelligent and honest would be admitting that he was wrong at this point...but this is a guy who believes that you can easily cure cancer with "garlic and peppers" and that all people who served in the Navy are "murderers", that "Ebola can be  easily cured via Vitamin C injections.", "The treatment for HIV is Vitamin C"
 and that "There is a conspiracy in medicine."...just like NASA, I assume.

A couple of people here have said that he's the smartest defender of FET they have...that's a very sad statement.


If you can't argue the math, attack the variables.   

If you are making your claim without evidence then we can discard it without evidence.

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Re: Using airline flight data.
« Reply #354 on: September 11, 2017, 08:20:45 PM »
The interesting thing about the FE'er's assertions that GPS is broken is that it was developed by the US military - primarily to allow cruise missiles and other long range/high-precision weapons to achieve ~2 foot precision on targets anywhere in the world.

The coordinates take you to real places if you attempt to follow them. The distance between the coordinates are based on a globe.

This isn't like wiring a house, Tom.  You don't just bring a whole bunch of it and stop spooling it out when you make landfall, because undersea cable is very expensive.  And even if you did, undersea cables have repeaters emedded in them every so many miles to boost the signal.  The owners know how many repeaters are in the cable, which means they know how long the cable is.

Are you an owner? Do you have access to their records for us?

As usual, we have the passive-aggressive effort to sow confusion and doubt rather than draw back the curtains and open the window to allow enlightenment and debate.

The point here is that the people who lay undersea cables - and the people who pay for them to be laid - and the people who run the system by remotely querying those regularly space repeaters would all have to be bundled up into your increasing spiral of conspiracy.

So now, the big undersea cable companies are a part of the same conspiracy as NASA, SpaceX, GPS and cellphone providers, the Russian, Chinese, Indian, French, South African and (now) North Korean governments?

Is there anyone besides Tom Bishop who is NOT a part of this coverup?

Isn't this just the teensiest bit paranoid?


Where did I say anything about a conspiracy? You are making a lot of assumptions on how submarine cable layers operate and I am asking for further information to demonstrate what was claimed is true. How do we know that they didn't run out of cable at one point and learned that they needed to bring more cable for these things?

This is an interesting Website :D. Not sure how I wound up here, and not sure how i ended up reading this thread.

Anyway. Tom, cable laying ships are extremely precise. I did a brief stint (9 days) aboard one such vessel, MV Wave Venture (http://www.cablesm.fr/Wave%20Venture.pdf). at the time I was working as an engineering intern for a company which contracted this vessel to do some work. I spent a lot of time in the operations room as well as on the cable deck and learned about the cable laying process.

The supplies aboard the ship are precisely measured and inventoried. This is necessary as the ship is enormously expensive to operate and running out of cable or other supplies mid-tour would be disastrous.

If you go to that PDF I linked, near the bottom are photos of the two cable handling drums. Those large drums play cable in and out. Their circumference is known and their motion precisely measured. Up in the control room, there are readouts on rate of cable pay-out, tension on the cable, amount of cable played out (easily calculated from drum diameter and # rotations of drum).

If the ship moves ahead too quickly and tension rises, the cable will snap. This would be catastrophic. To this end, tension is monitored careful and ship movement must be precisely controlled. The ship uses a dynamic positioning system, based on GPS. The accuracy is around 2 meters (the 400-something ft long ship can maintain its exact position within 2 meters and a degree or two of heading using directional "azimuth thrusters" and high performance GPS receivers positioned around the ship).

The GPS positioning system agrees closely with the cable run length, measured physically using the cable drum over long distances. This experimental "proof" of GPS accuracy is performed on every cable laying run. If the ship has moved 1 mile on GPS, but an unexpected amount of cable has been played out, this would be obvious in the ship control room (would probably indicate an unexpected underwater feature and the ship would back up/pick up cable and figure out what went wrong before re-laying).  Note that the cable laying plan also takes into account underwater topology (based on oceanic surveying, done via sonar).

-----

On another note of interest. A lot of land surveying these days is done via LIDAR. Basically an aircraft (or for smaller areas, maybe a small UAV) flies over and a lidar sensor takes millions of point distance measurements (worked based on speed of light and reflections, does not rely on any notion of round or flat anything). The end result is a dense "point cloud" or high resolution 3D map of an area.

Here's a  little clip that shows a bit of the process and what the results look like:

In order for the measurements from the moving aircraft to be combined into a coherent 3D model, the precise location of the aircraft & LiDAR at each moment must be known. Otherwise, the map would be an enormous mess (jumble of points). There are two major methods of inferring the location of the lidar at each time step

- SLAM (simultaneous localization and mapping)
- Sensor-based (GPS + Inertial measurements)

The slam method is much more difficult and is the subject of current research. With the slam method, in each new time step, you try "sync up" your new laser scan with the last one, finding an overlapping match and thus inferring the new position of the laser.

The sensor-based method uses a combination of GPS and an IMU (accelerometers and gyros) to log the precise position and orientation of the sensor in 3D space. By combining the long-term accuracy of GPS and short-term precision of inertial methods, and using filtering techniques, centimeter-level accuracy can be achieved.

In either of these methods, if the position of the laser cannot be accurately determined in 3D space for every moment in time (lets say GPS or IMU failure or inaccuracy), the map will look like a mess with all kinds of overlapping, incoherent points. In this event, the instrumentation will have to be repaired and data will have to be re-collected.

Now, if GPS worked consistently but with a scale offset, ie measured wrong distances, there are two issues. Firstly, the sensor fusion would fail (the inertial measurement unit would disagree with the GPS measurements). Secondly, the created map would be accurate, but at the wrong scale (distances incorrect). While the former takes some knowledge of signal processing to understand, the second can easily be analyzed empirically.

You can personally download LiDAR data sets, tagged with GPS data as well as aircraft data (altitude, position, velocity, etc). To prove to yourself that these GPS data sets are of accurate scale (since you don't seem to want to trust anyone else), you could download a dataset for somewhere local to you and look at the 3D point cloud. Measure a distance in the pointcloud between two known locations (lets say measure out the distance between two buildings). Then, in real life, go out there and confirm this data empirically using whatever equipment you like (laser range finder, radar, measuring tape, whatever).

In this manner, you will have proven the following:

A) the physically measured 3D pointclouds agree with published aerial maps (ie what you would find on google earth)
B) Aircraft are able to accurately determine their location, speed, position, orientation and altitude
C) GPS is able to accurately measure distances within a tolerance of several feet of absolute non-compounding error.

The underlying assumptions here are:

- The speed of light is ~ 3*10^8 m/s (required for lidar measurements)
- Time can be accurately measured (again required for lidar measurements)
- You are capable of personally measuring distance in the order of a few hundred feet to empirically verify the data

This is real, undisputable physical data that you can empirically verify yourself.

My credentials:

Bsc. Electrical Engineering & Computer Science
BSc. Aeronautics & Astronautics
Massachusetts Institute of Technology

My graduate thesis involves navigation of autonomous vehicles and as such relies on accuracy of systems such as GPS from a small, directly measurable scale up to larger areas. We work in GPS-available and GPS-denied environments and must fuse data from inertial systems, Lidar, RADAR, GPS, cameras, etc. to have both aerial and ground vehicles navigate precisely.

Hopefully my suggested experiment gives you an avenue to prove to yourself the performance of GPS :). I prove it to myself daily in my line of work. Once this business of distances is sorted, I believe the rest of the proof is clear cut using the geometry already presented by others. I should probably get back to work now.
« Last Edit: September 11, 2017, 08:34:44 PM by rb »

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Offline Tom Bishop

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Re: Using airline flight data.
« Reply #355 on: November 08, 2017, 04:25:22 AM »
The interesting thing about the FE'er's assertions that GPS is broken is that it was developed by the US military - primarily to allow cruise missiles and other long range/high-precision weapons to achieve ~2 foot precision on targets anywhere in the world.

The coordinates take you to real places if you attempt to follow them. The distance between the coordinates are based on a globe.

This isn't like wiring a house, Tom.  You don't just bring a whole bunch of it and stop spooling it out when you make landfall, because undersea cable is very expensive.  And even if you did, undersea cables have repeaters emedded in them every so many miles to boost the signal.  The owners know how many repeaters are in the cable, which means they know how long the cable is.

Are you an owner? Do you have access to their records for us?

As usual, we have the passive-aggressive effort to sow confusion and doubt rather than draw back the curtains and open the window to allow enlightenment and debate.

The point here is that the people who lay undersea cables - and the people who pay for them to be laid - and the people who run the system by remotely querying those regularly space repeaters would all have to be bundled up into your increasing spiral of conspiracy.

So now, the big undersea cable companies are a part of the same conspiracy as NASA, SpaceX, GPS and cellphone providers, the Russian, Chinese, Indian, French, South African and (now) North Korean governments?

Is there anyone besides Tom Bishop who is NOT a part of this coverup?

Isn't this just the teensiest bit paranoid?


Where did I say anything about a conspiracy? You are making a lot of assumptions on how submarine cable layers operate and I am asking for further information to demonstrate what was claimed is true. How do we know that they didn't run out of cable at one point and learned that they needed to bring more cable for these things?

This is an interesting Website :D. Not sure how I wound up here, and not sure how i ended up reading this thread.

Anyway. Tom, cable laying ships are extremely precise. I did a brief stint (9 days) aboard one such vessel, MV Wave Venture (http://www.cablesm.fr/Wave%20Venture.pdf). at the time I was working as an engineering intern for a company which contracted this vessel to do some work. I spent a lot of time in the operations room as well as on the cable deck and learned about the cable laying process.

The supplies aboard the ship are precisely measured and inventoried. This is necessary as the ship is enormously expensive to operate and running out of cable or other supplies mid-tour would be disastrous.

If you go to that PDF I linked, near the bottom are photos of the two cable handling drums. Those large drums play cable in and out. Their circumference is known and their motion precisely measured. Up in the control room, there are readouts on rate of cable pay-out, tension on the cable, amount of cable played out (easily calculated from drum diameter and # rotations of drum).

If the ship moves ahead too quickly and tension rises, the cable will snap. This would be catastrophic. To this end, tension is monitored careful and ship movement must be precisely controlled. The ship uses a dynamic positioning system, based on GPS. The accuracy is around 2 meters (the 400-something ft long ship can maintain its exact position within 2 meters and a degree or two of heading using directional "azimuth thrusters" and high performance GPS receivers positioned around the ship).

The GPS positioning system agrees closely with the cable run length, measured physically using the cable drum over long distances. This experimental "proof" of GPS accuracy is performed on every cable laying run. If the ship has moved 1 mile on GPS, but an unexpected amount of cable has been played out, this would be obvious in the ship control room (would probably indicate an unexpected underwater feature and the ship would back up/pick up cable and figure out what went wrong before re-laying).  Note that the cable laying plan also takes into account underwater topology (based on oceanic surveying, done via sonar).

-----

On another note of interest. A lot of land surveying these days is done via LIDAR. Basically an aircraft (or for smaller areas, maybe a small UAV) flies over and a lidar sensor takes millions of point distance measurements (worked based on speed of light and reflections, does not rely on any notion of round or flat anything). The end result is a dense "point cloud" or high resolution 3D map of an area.

Here's a  little clip that shows a bit of the process and what the results look like:

In order for the measurements from the moving aircraft to be combined into a coherent 3D model, the precise location of the aircraft & LiDAR at each moment must be known. Otherwise, the map would be an enormous mess (jumble of points). There are two major methods of inferring the location of the lidar at each time step

- SLAM (simultaneous localization and mapping)
- Sensor-based (GPS + Inertial measurements)

The slam method is much more difficult and is the subject of current research. With the slam method, in each new time step, you try "sync up" your new laser scan with the last one, finding an overlapping match and thus inferring the new position of the laser.

The sensor-based method uses a combination of GPS and an IMU (accelerometers and gyros) to log the precise position and orientation of the sensor in 3D space. By combining the long-term accuracy of GPS and short-term precision of inertial methods, and using filtering techniques, centimeter-level accuracy can be achieved.

In either of these methods, if the position of the laser cannot be accurately determined in 3D space for every moment in time (lets say GPS or IMU failure or inaccuracy), the map will look like a mess with all kinds of overlapping, incoherent points. In this event, the instrumentation will have to be repaired and data will have to be re-collected.

Now, if GPS worked consistently but with a scale offset, ie measured wrong distances, there are two issues. Firstly, the sensor fusion would fail (the inertial measurement unit would disagree with the GPS measurements). Secondly, the created map would be accurate, but at the wrong scale (distances incorrect). While the former takes some knowledge of signal processing to understand, the second can easily be analyzed empirically.

You can personally download LiDAR data sets, tagged with GPS data as well as aircraft data (altitude, position, velocity, etc). To prove to yourself that these GPS data sets are of accurate scale (since you don't seem to want to trust anyone else), you could download a dataset for somewhere local to you and look at the 3D point cloud. Measure a distance in the pointcloud between two known locations (lets say measure out the distance between two buildings). Then, in real life, go out there and confirm this data empirically using whatever equipment you like (laser range finder, radar, measuring tape, whatever).

In this manner, you will have proven the following:

A) the physically measured 3D pointclouds agree with published aerial maps (ie what you would find on google earth)
B) Aircraft are able to accurately determine their location, speed, position, orientation and altitude
C) GPS is able to accurately measure distances within a tolerance of several feet of absolute non-compounding error.

The underlying assumptions here are:

- The speed of light is ~ 3*10^8 m/s (required for lidar measurements)
- Time can be accurately measured (again required for lidar measurements)
- You are capable of personally measuring distance in the order of a few hundred feet to empirically verify the data

This is real, undisputable physical data that you can empirically verify yourself.

My credentials:

Bsc. Electrical Engineering & Computer Science
BSc. Aeronautics & Astronautics
Massachusetts Institute of Technology

My graduate thesis involves navigation of autonomous vehicles and as such relies on accuracy of systems such as GPS from a small, directly measurable scale up to larger areas. We work in GPS-available and GPS-denied environments and must fuse data from inertial systems, Lidar, RADAR, GPS, cameras, etc. to have both aerial and ground vehicles navigate precisely.

Hopefully my suggested experiment gives you an avenue to prove to yourself the performance of GPS :). I prove it to myself daily in my line of work. Once this business of distances is sorted, I believe the rest of the proof is clear cut using the geometry already presented by others. I should probably get back to work now.

Right... so you spend 9 days on such a vessel and that makes you an expert on exactly what kind of extra cable and supplies they bring along. Are we to assume that you interrogated the captain about his extra cable?

How do we know that there is no excess cable? You are assuming that a possible Flat Earth model must cause a cable shortage, when the opposite can be true as well.

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Offline xenotolerance

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Re: Using airline flight data.
« Reply #356 on: November 08, 2017, 05:56:48 AM »
Why you gotta necro an 18-page thread just to derail it? And avoid the other thread in the process? Is this a purposeful distraction tactic?

Like, an ad hominem (just an intern, amirite?) plus missing the point (he references LiDAR as evidence for GPS accuracy, you challenge cable length?) = low quality post

What the hell man?

QFT:
You sound like you're getting desperate Tom.  Your arguments don't even make any sense anymore and you're purposefully avoiding discussing the real points of the argument.

Distance is measured, time is measured, speed is defined by those 2 measurements and can be measured as well.  When you know 2, you can solve for the 3rd.  Round earth model coordinate systems have routinely delivered people to their destinations for a long time.  The FE model doesn't even have an accurate measurable map to test navigation with. 

If the earth were truly flat, it would be simple to create a flat map with no distortion that accurately measures all of the continents and oceans.  This map doesn't exist, therefor reductio ad absurdum the earth can't possibly be flat.  Done.


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Offline TomInAustin

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Re: Using airline flight data.
« Reply #357 on: November 08, 2017, 08:03:24 PM »

Right... so you spend 9 days on such a vessel and that makes you an expert on exactly what kind of extra cable and supplies they bring along. Are we to assume that you interrogated the captain about his extra cable?

How do we know that there is no excess cable? You are assuming that a possible Flat Earth model must cause a cable shortage, when the opposite can be true as well.

So out of all that, plus the man's qualifications and education you pluck that out? It was a good post, you should do a point by point commentary on it.  The way the ship uses GPS to stay within 2 meters is a good start.
« Last Edit: November 09, 2017, 03:52:13 PM by TomInAustin »
If you are making your claim without evidence then we can discard it without evidence.

Offline mtnman

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Re: Using airline flight data.
« Reply #358 on: November 09, 2017, 05:45:41 AM »

So out of all that, plus the man's qualifications and educations you pluck that out? It was a good post, you should do a point by point commentary on it.  The way the ship uses GPS to stay within 2 meters is a good start.
Claims conflicting with FE must be debunked if possible, otherwise a plausible reason must be established for ignoring them.

Re: Using airline flight data.
« Reply #359 on: November 09, 2017, 08:57:53 AM »
Right... so you spend 9 days on such a vessel and that makes you an expert on exactly what kind of extra cable and supplies they bring along. Are we to assume that you interrogated the captain about his extra cable?

How do we know that there is no excess cable? You are assuming that a possible Flat Earth model must cause a cable shortage, when the opposite can be true as well.
The cables are really big, they don't just have another one lying in the store cupboard, I think anyone on that ship would notice if they had an extra one.

He was working with the engineering I'm sure he would have caught on if they said they sometimes only use half, sometimes they need an extra one. Besides, they aren't the kind of cables that you just splice together on board or cut of the excess when you reach the far end.
We generally accept evidence from all  sources.

The only evidence for Round Earth celestial accuracy (assuming that timeanddate is even based on RET) is the evidence you collected with your friends last month?