About 37xx converted to 34xx satellites reception accuracy

**giuseppe66** · 20th February 2013, 06:00 PM

for flash back i've used Caty's procedure and files, firmware 4.5 for 37xx
in GPS folder i've always and only 3 files, any folders

**angelozip** · 20th February 2013, 06:16 PM

Originally Posted by x-trail

..So I've decided to do a different kind of test to check my converted 3760>3490
...I don't think that there is a real problem with the gps fix, I think there is a problem with the mathematical calculation of accuracy.
...It would be very interesting to have one 3790 and one converted 3490 side-by-side doing Diagnosting Logging for some time.
...Then we would compare their gpx files.

X-trail, its very good considerations, I agree with the approach. As you, I also had already placed in doubt the question of the value of the "accuracy" shown on screen gps. Despite being favorable to the method of dynamic measurement, what actually makes sense when it comes to road gps, contradictorily I did static measurements in order to verify the position indicated in relation to the real position. It turns out that the real position is difficult to measure, and even maps or Google Earth are not good references for accuracy. So I decided to take measurements over a official geodesic landmark, what has scientifically calculated coordinates and altitude.
To make more reliable the comparative test, would be necessary to have the values of measurements corrected (deviations in the troposphere, ionosphere ..) in post processing stages on some server on line of high level, but to do so would have to have the raw values collected before being processed by the gps, and transformed in the standard RINEX format in order to be post-processed. For this would have to make new measurements with the GPS connected to a notebook and program that would collect these data before they are processed by the gps. Sounds crazy, but it's a game very stimulating, I'm learning a lot, and maybe in the end, could at least respond safely the question of accuracy btw the values displayed on the screens of the original and converted 3790, among many other issues that do not fit comment here ..
But I'm slowly walking in these steps, but if anyone has any information on how to extract the data collected from satellite before being processed by the Nuvis / Etrex / Oregons, please let me know. It may be that the .bin format is raw data (gpx is processed), but it is a mere supposition. I have still researching it.
Despite my exaggerated pretensions about accuracy, which go far beyond the needs of the topic, there is no denying that yours proposal of compare tracklogs of the original and modified 3790, with measurements side by side, are ideal for the purpose of comparing the precision "real" BETWEEN the two firmwares. At the first opportunity, I will make that comparison.

Originally Posted by rfb

Angelozip,
Did you saw another big diference in your video from 37XX from the 37XX trasformed in 34XX?
See how long 34XX converted takes to scan the screen. Maybe another big diference from 37XX original "drives" for the 34XX firmware?

Rfb, I also noticed the problem of the image scan (flicker). It can be associated with different graphic driver of new firmware. I'll look more attention to this fact in the next comparison. On the other hand the3790 modified was with a protective film screen of low quality. At the next opportunity I will remove it ...

**dasilvarsa** · 20th February 2013, 08:28 PM

It's actually very east to check Static GPS Accuracy VS Map and Stability.
Set the unit Navigation to OFF Road (This will switch off Snap to Road) Switch to Norh Up and Switch off 3D Terrain
Walk to an intersection and Zoom + to Max.
Try this at Various Locations.
Of Course if the Map is wrong, then the test is meaningless but it will give you a good indication.
I've tried on 3490 and it's usually spot on, If I cross the road I can see it on the GPS Screen

**rfb** · 20th February 2013, 11:37 PM

Guys,

My unit:

Serial number: 1W70xxxxx

Unit Id: 380xxxxxxx

[]'s

**lolypop000** · 20th February 2013, 11:44 PM

@rfb
Do you try tutorial from giuseppe66 for better accuracy?
Do you have now better accuracy?

**rfb** · 20th February 2013, 11:56 PM

Originally Posted by x-trail

I don't think that there is a real problem with the gps fix, I think there is a problem with the mathematical calculation of accuracy.

It would be very interesting to have one 3790 and one converted 3490 side-by-side doing Diagnosting Logging for some time.
Then we would compare their gpx files.
What would we say if a 3790 with 4m accuracy and a 3490 with 20m accuracy, at the same place, same time and same weather, gave very similar gpx files...
If both devices gave gpx points very close to our real potition, then "maybe" accuracy is not so important if the "real" fix is always very close to our "real" position.

Hi,

I agree with you almost everything, but the real problem is not stationary.
The most problem is during walking/driving/moving with the GPS.

[]'s

**rfb** · 21st February 2013, 12:01 AM

Originally Posted by lolypop000

@rfb
Do you try tutorial from giuseppe66 for better accuracy?
Do you have now better accuracy?

Hi,

I'm doing a backup from my unit now.
After, I will try.

But driving at the real condition, just tomorrow I will have the results.

[]'s

**catymag** · 21st February 2013, 12:02 AM

Rodrigo do you have a similar thread on Nimrag forum? If yes what do other brazilian friends say ? Many users have bad accuracy?
It should be nice to share their results if you can report them

**rfb** · 21st February 2013, 12:19 AM

Originally Posted by giuseppe66

1) in nuvi 34xx with poor accuracy i've do a copy of all my folder and files on my pc, then i've delete all folders and files not important from nuvi;
2) flash back it to 37xx follow Caty's guide and files [Only registered and activated users can see links. ]
***Hidden content cannot be quoted.***
3) i've turn on and test accuracy of 37xx with essential files (no map, text, asr, jcv....) and i've good accuracy;
4) then i've flash to 34xx again with firmware 3.50;
5) Caty's solution "convert 37xx34xx.zip" and then Lolypop000's solution "region 139...";
6) backup on pc of "clean folder and files", share on post up;
7) test the accuracy with 3.5 firmware and it's good, like 37xx for me;
7) update with webupdater to firmware 7.6 and other files (voice, asr....);
8) test accuracy and it's good, like firmware 3.5;
9) update with my lifetime, map, asr, jcv.....
10 ) test accuracy like yuo can see in my picture in post up.

For me of course, i've not never see good accuracy on my 37>34 and now yes. Blu bars don't go up and down like "crazy" but now are enaught stable
I don't now exactly if there was a problem with firmware (i've use firmware 7.1 first time i've convert) or a problem with files because i've clean nuvi before flash to 37xx

Hi, Thanks for the tutorial!

But I'm not understand some steps:

4) then i've flash to 34xx again with firmware 3.50;
5) Caty's solution "convert 37xx34xx.zip"

Twice? Did you tried to convert 2 times?

Now I'm with 37XX, so I have to flash 34XX firmware 3.50 and after that "convert 37xx34xx.zip" from here:

"Another way to convert 34xx with logo and enable features :

Flash full 34xx firmware
Unpack the file to an empty SD card, turn nuvi off, insert card, turn nuvi on.
remove sd

and to return to 37xx ,its logo included:
Flash full 37xx firmware
same as above,unpack the file to an empty SD card, turn nuvi off, insert card, turn nuvi on.
remove sd

Download: Udated on 13.10.2012
added Video Player and Premium Point Addressing and updated Ldr.bin"

from this page?
[Only registered and activated users can see links. ]

[]'s

**rfb** · 21st February 2013, 12:27 AM

Originally Posted by catymag

Rodrigo do you have a similar thread on Nimrag forum? If yes what do other brazilian friends say ? Many users have bad accuracy?
It should be nice to share their results if you can report them

Hi,

I think most people that converted their units do not realize that issue in my forum...lolol

But I put a notification about this issue and a link for this forum.

But I know that another big brazilian forum have some users working together with us.

They are watching here...

[]'s

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