Proof that poor GPS is more than just a firmware issue?

[paddyb]

Now that we are a two SGS household, it gives me the opportunity to do some side by side testing of the various GPS fixes and tweaks that have been discussed.

However, before I even got to that stage, something was very apparent right from the start. Setting the two phones side by side, which both have JF3 firmware and the same GPS settings, using GPS Test, my girlfriends phone gave much better results, getting more fixes and higher SNR’s, and accuracy down to 16 feet (but still fluctuating wildly), whereas my accuracy only hit 32 very occasionally.

So, same phone, same firmware, but different results. The only other difference was that she is on Vodaphone and I’m on Orange. Should that make any difference?

This seems to suggest that it might not be just a firmware issue?

[someuser]

It's widely known JF3 was particularly bad for GPS. You may want to flash to a newer ROM on both and see if your results vary. I'm encouraged a lot by some positive GPS feedback in Canada for their new JH2 firmware and look forward to the European version likely out very soon.

[paddyb]

It's widely known JF3 was particularly bad for GPS.

But why would two phones with the same firmware give such different results?

I’m reluctant to update my firmware until an official update is available (JM1 has not been released to Orange contract customers as far as I can ascertain, but hopefully soon). When both have a newer firmware I’ll try again and see how they compare. If I’m still not happy, then I’m going to look into getting a replacement handset from Samsung, which is why i don’t want to risk my warranty by flashing anything unofficial.

I got my phone very early on, actually took delivery on day 3 of its UK release. I just wonder if there was a slight flaw with the first few batches, maybe something to do with the GPS antenna that was later rectified? There are certainly people on this forum and others who seem happy with their GPS on early firmware and also people who have the latest firmware and are still having problems. How are people who’ve purchased their phones more recently found their GPS?

[someuser]

But why would two phones with the same firmware give such different results?

This I have no answer for.

But to answer your other questions - I was very happy with the GPS on mine with my original firmware - JF1. Phone bought July 6. Then I flashed to MoDaCo's R2 (I think from memory Jf5) and the GPS was appalling but the rest of the phone was great. Then Modaco R3 JG5 (GPS just as bad, phone even better). Then I flashed to JM2, No MoDaCo and it's GPS is great again but the lag is back like the original firmware. So I have never had the phone all working at once but at some stage I've been happy with every aspect of the phone, just not all at once. Now waiting for a Firmware/Custom ROM that pulls it all together and hopefully a dose of Froyo too so I can run flash if I want to I've tried all the lag fixes but none have worked as well for me as having MoDaCo Custom Rom installed.

[Doomed]

But why would two phones with the same firmware give such different results?

I believe it's also to do with your networks. I'm sure the GPS uses the networks as well to help improve the accuracy of the fix

[SwedishSax]

But why would two phones with the same firmware give such different results?

Because the hardware might still be different.
It's not just software that goes through revisions, hardware does too. Two phones of the same make and model could conceivably contain GPS chips of different revisions.

But as someone else noted the networks do make a difference too, at least for assisted GPS which makes use of additional information such as the cell base station's location, which is known to a high degree of accuracy.

However, I do not see this as proof there is a hardware issue. I think the problem is in Samsung's interpretation of the GPS signals received from the different satellites.

[paddyb]

Thanks for your responses.

Because the hardware might still be different.
It's not just software that goes through revisions, hardware does too. Two phones of the same make and model could conceivably contain GPS chips of different revisions.

Probably not as obvious as a different chip, but maybe something to do with the antenna or minor circutry changes?

But as someone else noted the networks do make a difference too, at least for assisted GPS which makes use of additional information such as the cell base station's location, which is known to a high degree of accuracy.

I'm basing these findings on GPS Test. As i understand it, this app is only reporting on what satellites it can see, so cell base stations shouldn't come into it, or am i wrong?

My GPS has now stopped working completely after trying some of the tweeks mentioned in this forum, even though i have now set everything back to how it was. If i can get it working again (a factory reset?), then i will try the tests again in Flight mode, which should take carrier signals out of the equasion.

[AAA]

I believe it's also to do with your networks. I'm sure the GPS uses the networks as well to help improve the accuracy of the fix

Hello, This is an interesting thread and correlates with my findings with my two SGS. My "data" isn't perfect as I owned the phones sequentially (because I'd sent the first one back as faulty due to the GPS issues) so couldn't do a side by side test as you have, but my conclusions were that both phones had identical official firmwares (at least the filesnames were the same..) on the same network (orange) but the performance of the GPS was very different (i.e. much improved, from non-useful to useful) with the second phone.

That led me to believe that it's not just simply a firmware issue and it's not network related (and I can't see why it would be anyway - unless you use the assisted GPS function, which I don't)

I still get occasional glitches - where the Satnav software thinks I'm 2 streets away for 30 seconds or so, and I sometimes (I've not worked out a pattern of when or why) find that googlemaps fails to turn the GPS on (no GPS logo at the top of the screen) so I have to go into settings and turn GPS off and then on again (Grr..) but otherwise fine. (Though I can't workout how to keep the screen "on" when using googlemaps which makes it a bit annoying to use in the car.. - any advice would be much appreciated..)

Anyhow - it wouldn't surprise me to learn that there's a bloke at the end of the samsung production line employed as a short-term fix to use a thin screwdriver to just prise the GPS antenna away from the circuit board by a couple of mil to improve reception. (or some similar bodge) If he gets it right you are lucky, if he gets it wrong you are screwed. As a further fix, some firmwares might have the gain wound up on the antenna, or the processing code improved - but then that probably causes too much heat build up or too fast a battery drain...

If you get one and the GPS doesn't work to your satisfaction I'd just return it like I did, and keep returning them until you get one that works. Personally I'm not keen with my simlocked phone to go down the cooked-Rom route and void my warranty just yet..

[paddyb]

Thanks for the feedback AAA

I’m going to do one more test tonight in Flight Mode, and if the two still seem vastly different then I’m going to phone Orange and ask for a replacement. Did you get your replacement within the first 7 days or after? Seems like it’s possible to get one afterwards as simvaughan1 on this forum did:

http://androidforums.com/samsung-gal...ml#post1432132

Are you sure yours is simlocked? I had assumed mine was, as I got it directly from Orange, but found my girlfriends Vodaphone sim worked in it ok. That’s the only thing that’s stopping me sending it back today, as I don’t want a simlocked one back in return!

[paddyb]

Ok, tried 2 SGS’s, both unlocked and running JF3 side by side in Flight Mode and wi-fi off, so the only thing that Maps and GPS test can use is the GPS, no cell tower etc info.

It’s an overcast night here in the UK and I’m testing indoors, but my girlfriends SGS on Vodaphone got a reasonably accurate location in Maps, whilst mine on Orange could only report “Your current location is temporarily unavailable”. Her satellite icon was still, mine never stopped flashing.

In GPS Test, hers had accuracy down to 32ft and 3 or 4 sats in use and 6 or 7 in view, with SNR’s occasionally over 40. Mine could often only see 1, occasionally up to 5, but they never went off grey.

I tried switching positions and different locations in the house, but hers always came off best.

I’m no expert, but this seems to point to hardware differences? I’m going to ask Orange for a replacement handset tomorrow.