Ok, i'm understanding most of that, but i wouldn't have thought that DOP was a problem given the spread of the sats in the pics. The triangulation should be quite good from the spread shown, and in fact that spread was similarly maintained though the entire test run described in Post #29.
So, why does 34x0 convert suffer from accuracy problem especially when moving? If we discount WAAS, DOP, signal strength.. what's left? Fw somewhat incompatible with the 37x0 gps hw on these converted units? Dasivarsa's genuine 3490 gets consistent 3m reading same as my original 3790 (I still think that's not realistic btw, if there is no meaningful WAAS correction how can that accuracy precision be maintained by a 'non-professional' basic gps receiver?).
So Giomen, how about you or Loly or someone please mod 34x0 v7.6 fw with 37x0 gps fw from wotever region it's in, post an *.rgn file and i and any other intrepid souls will flash it to our 34xx converts? Pretty please??
EDIT: Made a reply to the first part of your post also, but a rare flash of good taste and sense led me to decide to delete it after a few hours. However, first i copied it [Only registered and activated users can see links. ] in Aussie Gems if you wanna have a look (you can even reply to it there if you're game!).
Last edited by Neil; 2nd February 2013 at 10:35 AM.
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Ok, i'm understanding most of that, but i wouldn't have thought that DOP was a problem given the spread of the sats in the pics. The triangulation should be quite good from the spread shown, and in fact that spread was similarly maintained though the entire test run described in Post #29.
So, why does 34x0 convert suffer from accuracy problem especially when moving? If we discount WAAS, DOP, signal strength.. what's left? Fw somewhat incompatible with the 37x0 gps hw on these converted units? Dasivarsa's genuine 3490 gets consistent 3m reading same as my original 3790 (I still think that's not realistic btw, if there is no meaningful WAAS correction how can that accuracy precision be maintained by a 'non-professional' basic gps receiver?).
So Giomen, how about you or Loly or someone please mod 34x0 v7.6 fw with 37x0 gps fw from wotever region it's in, post an *.rgn file and i and any other intrepid souls will flash it to our 34xx converts? Pretty please??
EDIT: Made a reply to the first part of your post also, but a rare flash of good taste and sense led me to decide to delete it after a few hours. However, first i copied it [Only registered and activated users can see links. ] in Aussie Gems if you wanna have a look (you can even reply to it there if you're game!).
I play with my 3490 and convert it to 3790.
On original 3490 i have 3-5m accuracy, when i convert it to 3790 i have 7-15m accuracy.
Then i convert back to 3490 and still 7-15m accuracy.
Then i go in satellite page and add finger for 5sec on height and set Predicted EPH and cold start.
Turn off nuvi and on again and whait for satellite and after 2 min i have 3m accuracy with 7 satellite bar.
In 37xx/34xx if you go to Debugging menu/Developer GPS Tools ,Predictive Ephemeris Age is not active: I mean it doesnt retain settings you set. Even in satellites page even if I check the two you told above, settings are not retained.
Not sure this feature works in 37xx to 34xx.
When you set it, whait for satellite then turn off nuvi and turn on again and nuvi will turn on with this settings.
But in height screen is empty becouse nuvi turn on with this settings only first time.
When you set Predicted EPH and cold start, this is save in NVM and executet in next boot (this is like chkdsk on PC, where is executet on next boot)
I play with my 3490 and convert it to 3790.
On original 3490 i have 3-5m accuracy, when i convert it to 3790 i have 7-15m accuracy.
Then i convert back to 3490 and still 7-15m accuracy.
Then i go in satellite page and add finger for 5sec on height and set Predicted EPH and cold start.
Turn off nuvi and on again and whait for satellite and after 2 min i have 3m accuracy with 7 satellite bar.
Which would explain perfectly why i didn't notice any difference in accuracy when flashing back and forth between 3790 and 3490 several times.
Do i understand correctly, Loly? You are saying when you convert 37xx to 34xx or back, your unit needs to have those settings checked, be rebooted before satellite fix, and the accuracy problem should be fixed permanently with no need to re-check and reboot each time (unless you reflash)?
'Thanking Posts' are banned. To thank someone, and/or to see hidden links and content, use the [Only registered and activated users can see links. ] button below left of the helpful post then refresh your browser [F5 key]. 'Thanking Posts' are banned. Please don't spam. Posts serving no purpose other than to thank or to ask about hidden links are trashed or deleted, it's GPSPower's policy. Please don't spam. [Only registered and activated users can see links. ] should make their first post as a new Intro Thread in [Only registered and activated users can see links. ].
I try all that i think of but i have accuracy 7-15m ( before 3-5), then i see this settings for Predicted EPH and cold start.
I set this settings but no difference when i have satellite lock.
Then i turn off and back on nuvi and go to satellite page and whait for satellite lock.
First was 133m accuracy then go down to 3-5m.
I again turn off and back on nuvi and go to satellite page and after 10 sec i have 3-5m accuracy
Every time when i start nuvi i have now 3-5m like before flashing.
So this is procedure:
Go to height page and set Predicted EPH and cold start (you set this only one time)
Go to satellite page and whait for satellite lock
Turn off and then again on your nuvi.
Go to satellite page and whait for satellite lock (after 1-2 min you will have 3-5m accuracy)
Turn off and then again on nuvi and you will have satellite lock in about 10sec with 3-5m accuracy
When you again convert nuvi to 37xx or to 34xx, then you must use again above procedure, but if you flash 37xx to 34xx and you stay on 34xx then you do this only one time.
p.s.
I have Pc beside window and have 3-5m accuracy in my room
I don't know if i have only luck, but this procedure work for me, i hope that will work also for other people.
Last edited by lolypop000; 8th February 2013 at 11:11 PM.
I again turn off and back on nuvi and go to satellite page and after 10 sec i have 3-5m accuracy
Followed your procedure
I had a good accuracy in sat page and this hasnt changed, but when I start nuvi even after clearing non vol I get satellites in a while Nice!
Thanks
I play with my 3490 and convert it to 3790.
On original 3490 i have 3-5m accuracy, when i convert it to 3790 i have 7-15m accuracy.
Then i convert back to 3490 and still 7-15m accuracy.
Then i go in satellite page and add finger for 5sec on height and set Predicted EPH and cold start.
Turn off nuvi and on again and whait for satellite and after 2 min i have 3m accuracy with 7 satellite bar.
Loly, in personal test I did with 3790/3490 (static mode), there are apparently better accuracy, but I believe that we can only be sure when someone makes a comparative test in dynamic and static mode, side by side, between a 3790 original and a 3790 modified. After this comparitive we can make sure that your method works perfectly, and that's what we all hope. Will have been a great discovery..
Last edited by angelozip; 9th February 2013 at 04:38 PM.
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