On balance I think you are right Angelo. Right at least to the extent that the SBAS info cannot be properly processed by 3xxx series imo. But obviously my converted 3790>3490 can 'tune' sbas sats. I've seen PRN 153 and 193 with decent signal strength, but with conflicting results. With 153 showing, the accuracy seemed worse, with 193 it was better, (apparently). But this was maybe just random and the presence of the sbas signal was simply because the unit was unable to get enough signals from true gps sats so it locked on the sbas sat in desperation, who knows? Much more testing would be required to test that theory and prove one way or another if it can actually use the signal info. The fact that it can receive the signal is however indisputable. My layman's guess is that sbas is a 'red herring' and the real answer for all converts lies in modding the fw because the real problem is fw/hw partial-incompatibility. In my convert checking Predicted EPH and Cold Start then following Loly procedure resulted in faster lock and apparently improved accuracy. As dasilvarsa points out, this is about 'hotfix', and is predictive to give the unit a 'heads up' on where the sats should be. So to a certain extent, it's illusionary 'mirrors and cigar smoke' and is not really about accuracy. But in some units, accuracy 'apparently' improves. I say apparently because maybe that's illusionary too in that i don't really believe that original 3490 and 3590 really can maintain constant 3m accuracy, and my restored 3590 attained constant 3 m with fast lock after the procedure was done on it and it didn't demonstrate that before.
Summing up, this is what i think:
1. SBAS/WAAS is of no consequence and merely incidental. It happens because the 34xx convert is sometimes not able to lock to sufficient true GPS sats, so it picks up a SBAS sat signal but really can't use the broadcast info.
2. Setting Predicted EPH and Cold Start helps some units to show fast lock and improved accuracy, but it may not be really helping accuracy in those units in fact, and doesn't seem to help accuracy in others at all.
3. The real problem (especially for the unfortunates with 15-20m) is because of partial-incompatibility and the only way to fully overcome that is by a fw mod.
Just putting it out there as usual. Simply playing 'blind man's bluff' with no scientific backing.... but my money's on modding fw. This needs more brain-storming, where's Loly?
'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 think that those that have "unacceptable GPS Performance" should revert to 37xx if it solves the problem.
The difference between stupidity and genius is that genius has its limits.
Albert Einstein.
Can anybody try with this and report about accuracy?
[Only registered and activated users can see links. ]
1.) Extract rar from above link
2.) Rename in .System your GPS folder to GPS1
3.) Add GPS folder from step1 on your nuvi in .System folder
4.) Go outside, whait for satellite lock and make procedure for satellite accuracy again
We need more users like you @rfb who try to solve this mistery
In my test i've see that is not important how many satellities you have but how many signal you have on i single satellites. another test that i've do is for receive more satellites: i've delete all files in GPS directory then turn ON and (on open space), go to secret menu and select EPHER....and COLD.. and wait for 10-15 minutes for best reception without go out from that menu. I've see the reception of all satellites but accuracy always 8 - 12 about. So i've understund that accuracy is depending from quality and not from number
I compare 37xx FW v5.00 with original 3790 GPS folder and mt.nvm inside.
You can find the same number 2x in 37xx FW but this number ar not present in 34xxFW
[Only registered and activated users can see links. ]
[Only registered and activated users can see links. ]
Then i compare 34xx FW v7.60 with GPS folder from nuvi converted from 37xx to 34xx and compare this mt.nvm.
You can see that after convert mt.nvm change number and this number you find 3x in 34xx FW, but this number is not present in 37xx FW
[Only registered and activated users can see links. ]
[Only registered and activated users can see links. ]
[Only registered and activated users can see links. ]
Bookmarks