Gps


AlexW

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This has endless of possibilitys...
Make a 0-100 Km/h times to test car accelleration.
Make 402m (1/4 mile) (dragstrip) timing for those who are into car tuning... and racing... (maybe I'm the only one here though :)
With a accurate clock and a accurate GPS you can measure all sorts of car performance...

And yes... you can make a cool navigator with maps and speech and so on... (just have to hook it up to the car stereo...)

Does this GPS measure height also?

I'll buy this (even though I already have a USB GPS for my laptop...) this would be the ultimate cool tool for GP32...

-------edit
Search the web and found this... this would be a killer app for GP32 GPS... would sell many if it can half of what this can... and I don't know of accuracy of Nigel's GPS...
http://www.m-techautomotive.co.uk/vbox/aboutvbox.htm

The best of them costs
Price £7,495+vat

And GP32+GPS+Software would cost MAX £300...
Plus the added ability to display directly and have sound and so on...

Well I'm dreaming of course but it could be done...
 

mattmagoo

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This has endless of possibilitys...
Make a 0-100 Km/h times to test car accelleration.
Make 402m (1/4 mile) (dragstrip) timing for those who are into car tuning... and racing... (maybe I'm the only one here though :)
With a accurate clock and a accurate GPS you can measure all sorts of car performance...

And yes... you can make a cool navigator with maps and speech and so on... (just have to hook it up to the car stereo...)

Does this GPS measure height also?

I'll buy this (even though I already have a USB GPS for my laptop...) this would be the ultimate cool tool for GP32...

-------edit
Search the web and found this... this would be a killer app for GP32 GPS... would sell many if it can half of what this can... and I don't know of accuracy of Nigel's GPS...
http://www.m-techautomotive.co.uk/vbox/aboutvbox.htm

The best of them costs
Price £7,495+vat

And GP32+GPS+Software would cost MAX £300...
Plus the added ability to display directly and have sound and so on...

Well I'm dreaming of course but it could be done...

GPS for Pcoket PC and dedicated GPS systems are usually roughly accurate to 10 yards, which would be too inaccurate for what you want
 
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Squidge

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Some common causes of GPS's calculating your position wrong are:

Atmospheric Errors cause +/- 5 meters.

The ionosphere is a band of charged particles in the atmosphere. Satellite signal is slowed as it passes through the ionosphere. This delay creates a miscalculation of the satellite's distance resulting in receiver position error.

Horizontal Dilution of Precision (HDOP) is caused by satellite geometry. If the GPS receiver is using satellites in the same area of the sky as opposed to being distributed across the horizon, the location of the receiver becomes increasingly uncertain. Good geometric position of the satellites is ideal.

Ephemeris Error +/- 2 meters - GPS satellites are launched into very precise orbits; any change in the orbital parameters, though, can result in a slight error.

Satellite Clock Error +/- 2 meters - Slight inaccuracies in the satellite's atomic clock can result in position error.

Receiver Error +/- 1 meter - Sometimes the receiver will round numbers, or perform incorrect calculations due to electromagnetic interference.

Also, don't forget that GPS signals are purposely detuned for civilian use (and so can cause an additional +/- 15 meters on top of the above) - only people like the MOD have an accurate GPS signal.

DGPS solves some of these issues, but not all of them, but I don't think Nigel's GPS receiver supports DGPS (Differential GPS - calculating inaccuracies using a known point).
 

AlexW

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Squidge, you seem to know a lot about GPS. All the measuring errors you mention would these cause a flip flop of data when you stand still for example?
Hmmm... difficult for me to explain but if I stand still it can jump 20 meters from the first updated positition to the next updated position (still not moving the GPS reciever?)
Or is it more like the first updated position is more or less 20 meter of the actual position? and when I move it around it will be accurate from the first position (i.e I go 5 meters and then it shows I went 5 meters from the first position or is it +-20 meters)

Don't know if you understand... (I'm from Sweden so I have some difficulty making me understood in English I guess...)
 

Squidge

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If you are standing still holding your GPS, your most likely to see the location constantly changing, but staying within 10 metres of accuracy.

So you could, for example, take a reading at one point, walk 10 metres in any direction, take another reading, and find it's the same as last time, or could be saying your only 5 metres away, and then a few seconds later say the correct value, etc.

However, if you take two GPS receivers, one that is stationary, and one that you take around with you, they will both get the "wrong" results, so you can more accurately get your location by using the difference between them. Since the chances are affecting both receivers, by doing it this way, you can typically get within a few metres accuracy.
 

finty

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Some fisherman in Donegal claimed that every morning when he went out to sea his GPS said he was on land, but when the Iraq war started it said he was out at sea.

Sounds reasonable to me.
 

Squidge

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That's perfectly possible. The government has the capability of lowering the resolution of gps should it think it could give someone a technical advantage by using it (called "Selective availability" I believe). Of course, these resolution changes are invisible to people like the MoD who always get full resolution.

The lower resolution, when used, is 100m rather than 10m.
 

mr.spiv

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Also, don't forget that GPS signals are purposely detuned for civilian use (and so can cause an additional +/- 15 meters on top of the above) - only people like the MOD have an accurate GPS signal.
Isn't this "removed" these days as there was no point of using it anymore?
 
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AlexW

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OK, I understand... I guess this is why the Racelogic GPS logger costs about £7000, its accurate...

+-20 meters or more would be OK for a map application and so on...
But not for a car logger app...


Thanks for the info!
 

Squidge

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Also, don't forget that GPS signals are purposely detuned for civilian use (and so can cause an additional +/- 15 meters on top of the above) - only people like the MOD have an accurate GPS signal.
Isn't this "removed" these days as there was no point of using it anymore?
Almost. By using DGPS, you can get the resolution down to a few metres, but the government still reserve the right to reduce the resolution to either 10m or 100m without notice.
 
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