Database Develop

what is the reasonable time for gps fix?

as per subject what is the reasonable time for gps fix? can installed applications effect gps fix? what about clouds? could it be hard to get fix in cloudy whether?

Don't know whats normal but sitting in my house with TT I get 3-4 bars in about 5 seconds once I open TT. This is on the kaiser not the fugly
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goto www.gpspassion.com and you'll find a wealth of gps info. Reasonable time with quick gps is about 5-20 seconds with a good signal (outside) on the kaiser. Clouds can affect things but I've never seen it hamper anything.

I wonder if there is a difference in aquiring signal between the Kaiser and tilt? I have not seen much issue on the kaiser but there are alot on the tilt on several boards?
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my kaiser takes very long at the moment

It can take up to a minute or so if you haven't used it in a while. Sometimes it pretty quick (like <15 seconds, esp when it has been used in past hour or so).

I used the GPS today for a road trip. . . fired up QuickGPS and then launched my mapping software. It only took about 10 seconds for the software to "find" the onboard GPS -- and this was the first time I had used it in the 24 hours I've had it.

You need to use QuickGPS first.

GPS position and bad position fix

I have had GPS receivers previously as well as used some, both normal consumer as well as aviation grade GPS systems. Now I have the Kaiser/TyTN II and I am impressed with how sensitive it is! For not losing signal or dropping position I am amazed, good stuff!
BUT ... since it uses so much battery when the GPS is running, I sometimes turn it of for a while, then on later on again. Especially when moving a lot while being turned off (flying or driving), turning it back on can sometimes give problems getting a new fix! Sometimes it gets a fix quickly, but it is hundreds or thousands of miles off. I know it is complicated 3D math for a GPS to aquire its position, and I know it is possible to get a false lock, but the GPS receivers I have tried and had previously never accepted a bad fix.
The unit knows where the satellites are supposed to be, given the time and approximate position, so that is what it assumes. But when it has been off, and then on again and only moved some hundred miles, it can get this false position fix that it cannot get out of easily. If I turn it off again and wait until none of the previous satellites are in view (flying for another hour for instance), it finally realizes it has to start over with a new fix. Older GPS units I used/had often had an option of making a cold start fix (search the sky, autosearch or other names for basically the same thing). It is also sometimes possible to specify or change the last "known" position of the GPS to make it easier for it to get a new fix again. The latter requires that you either can find your rough position in a map or you know a rough lat/lon position.
So, two questions:
1) How do I break a bad fix, tell the unit it is on a wrong path - do a renewed search the sky?
2) How can I change the "previous GPS position" so the GPS unit is forced to assume another position?
I have some GPS applications where you can change the last know position, but it only seems to stay in the program, it is not fed back into the GPS receiver.

No comments here? Must be others with the same problem. Even the oldest, most basic GPS units had an option to enter position manually, or to enforce a new search from scratch. There must at least be some kind of reset function! (NOT hard reset, thanks!)

LGB said:
No comments here? Must be others with the same problem. Even the oldest, most basic GPS units had an option to enter position manually, or to enforce a new search from scratch. There must at least be some kind of reset function! (NOT hard reset, thanks!)
Click to expand...
Click to collapse
I tried google maps and discovered that my actual position was off by some 50 meters from where I actually was. Then I also discovered that in the area I was, if you superimposed the roads on top of the satellite image in Google maps, it was also set off, by about 10 meters only.
Ever since I tried Google maps, my GPS fixes correctly and updates data all the time, but with some programs speed remains 0 and direction remains north even if I move around. After re-flashing the original rom everything is back to normal. Do you know why this happened?

I have got the same problem.
Once after using TrackMe and once after getting my position in Virtual Earth Mobile.
Both times i have used the gps only for a short while and then closed it. On the next start the position has been several hundreds of kilometers off and the speed shows several hundreds kph although I stand still.
Both times the gps has not been ok until the next day.
I have tried to soft reset and also updated the Quick GPS with no result.
I found this thread Kaiser GPS positioning problems which looks a lot like the same.
I have been using the GPS a lot more frequently recently and at first I thought it was these two apps, but now it seem more general. Before I used TomTom on a few occasions with no problem, but then the GPS was on for a longer period.
Anyone else?

gps

i got a question on gps. HOw fast does your tytn ii gps find signal? mine takes forever like 3-4 min? is there a way to increase the signal search? thanks

Which radio are you using?
Mine takes couple of seconds max.

pinx said:
Which radio are you using?
Mine takes couple of seconds max.
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I think it depends upon the radio a lot. Some radios are very quick (I am currently using NIKI XX.17 as I need quick GPS locks - now takes seconds not minutes), others are not.

When I first got my kaiser, T-mobile vario III the GPS was very quick to get a fix taking less than one minute to get the first fix after boot up and subsequently a matter of a few seconds.
Unfortunately this was about the only thing that was quick though, so I installed one of Dutty's ROMs which vastly improved the overall performance of the device for most tasks, except getting a GPS fix which all of a sudden was intolerably slow, sometimes almost impossible.
I experimented flashing various radios but nothing seemed to make much difference so I kind of gave up. The other day I upgraded again, to Dutty's latest ROM and all of a sudden my GPS performance is back to how it was when I first got the kaiser, despite the fact the radio version included in the rom is the same as the one I had before. So I'm very pleased about this, but also perplexed. I don't know what factors influence the speed of getting a GPS fix but for me Dutty's latest ROM is good so maybe you should try that.
One thing that I did notice is that getting a GPS fix was always quicker when travelling in the car not standing still.

look9001 said:
One thing that I did notice is that getting a GPS fix was always quicker when travelling in the car not standing still.
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Click to collapse
Which is strange... Normally GPS's are quicker to fix when stationary rather than moving...
I'll be getting mine soon, so once I have it, I will test with the T-Mobile standard and - if I get it installed, being a WinMob n00b myself that is by no means certain! - with Dutty's latest...

CescoAiel said:
Which is strange... Normally GPS's are quicker to fix when stationary rather than moving...
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Click to collapse
It is strange isn't it? But I'm sure it was true in my case. For example I once walked to work with the GPS switched on as a test, I was holding it in my hand so it had a direct line to the sky at all times. When I got there about fifteen minutes later it still hadn't got a fix. The next day I drove somewhere and after about two minutes it had a fix.

As long as I'm outside (or in the car) under clear sky, I get a lock in Google Maps or Telenav in only a few seconds. Inside my apartment, but near a window, Google Maps will eventually get a lock, but it can take it 3-5 minutes to do so. In my office, which also has a window but which faces out to a courtyard surrounded by brick walls (and up 5 stories above my floor), I just cannot seem to get a fix at all.
Outside with clear sky above though, moving or stable, it is very quick - never more then 10s and usually far less.

What kind of buildings and other obstructions were around you? In order to get enough fixes to pinpoint your location it will often have to see sats out to some pretty steep angles. One guy we met who does commercial GPS systems showed us where the birds were from out on a beach. The 4th one was only something like 20 degrees above the horizon out over the ocean.

Inaccuracy of GPS

Well i have a question.
When i use TomTom or IGO the position on the screen is always about 50 meters off to where I actually am.
So since IGO & TomTom Both have the same behaviour i guess i should look at the GPS module.
My old S730 was always spot on... when i looked at the screen and saw a turn on the left, there actually was a turn to the left.
Anybody knows how this can be solved ?

My TD2 does not have this problem, perhaps there is an issue with your particular phone?

I thoght about it before and found out that it was not inaccuracy but the delay GPS chip needs to calculate your position. Do one test. Some time when you stop at a red light and you know you've waited for about 5 secs, check your position then. I believe it will be accurate then.
I noticed that some GPS's try to calculate your current position based on direction and speed you had few seconds ago. I found out about it one time when I waited at the red light in a long tunnel. Obviously there was no signal there, but when I stopped, GPS kept on showing that I was moving about 40MPH for several seconds before it finally showed lost signal message.
Some GPS's do calculate your position ahead of time and some don't.

Maybe it was because i had assisted GPS turned on...
If you do a search on AGPS LAG (ANY HTCPRODUCT WITH AGPS) then you will see enough posts that speciffically deals with this problem...
My old phone is SPOT ON with TT and my new 2 times faster phone is less accurate, and in a street with lots of turns, take a-lefts etc it's quite important to rely on the machine. And when the machine says turn left on the next corner, is that left the one i am currently at or the one 20 meters ahead from where i am now....
It should be just as with my old phone spot on

Well disabeling AGPS definitely works...
I am now about 20 meters behind all the time. This seems acceptable although I keep finding it strange that my older phone was way more accurate.....

you mean disable QuickGPS or disable AGPS in Advanced Config??

It is definitely a lag issue, not a precision issue: my TD2 internal GPS is at least as accurate as my Qstarz bluetooth GPS logger, and this one has a dedicated large antenna and good GPS chipset. TD2 sensitivity is also comparable, maybe even better inside building, and the time before locking a signal from coldstart is also comparable or better...
BUT there is a lag of maybe 30 m around 50 km/h in my car, and it is is indeed quite noticeable for driving directions...No big deal for me, as I do not rely on voice instruction but always have a quick peak at the screen (I was bitten by ambiguous instruction often enough in the past with other GPS system to have developped this quick peak habit ;-) )..but this lag is indeed anoying...
I'd like to try the TD2 using the external GPS through bluetooth, if I find time to do it this WE I will post my conclusions...

well0549 said:
Well i have a question.
When i use TomTom or IGO the position on the screen is always about 50 meters off to where I actually am.
So since IGO & TomTom Both have the same behaviour i guess i should look at the GPS module.
My old S730 was always spot on... when i looked at the screen and saw a turn on the left, there actually was a turn to the left.
Anybody knows how this can be solved ?
Click to expand...
Click to collapse
I use to have the same problem as you, so, I've tried the tweak referred in this post http://forum.xda-developers.com/showthread.php?t=514912 and it did the trick for me.
I use iGo8 and NDrive and the accuracy improved a lot, it's almost spot on, no matter what speed I'm driving.
Regards,

I was in my mates Audi TT the other day. He has the built in GPS in the dash board. I noticed there was as much lag as you see on an HTC device.
Also was in a car a few months asgo with someone who had a stand alone TomTom device and that too had lag.
Unless you're paying thousands of Dollars for millitary grade navigation equipment, i wouldn't spare the lag issue another thought.

Not long now ...
There's a bigger lag comming if the media are to be believed (and based on everything that comes from the tele, radio and newspapers these days - there're probably not - they can't even get the weather right)
http://news.sky.com/skynews/Home/Technology/GPS-Network-Could-Fail-Next-Year-Leaving-Sat-Nav-Useless-US-Government-Accountability-Office-Warns/Article/200905315284843?lpos=Technology_Carousel_Region_4&lid=ARTICLE_15284843_GPS_Network_Could_Fail_Next_Year_Leaving_Sat_Nav_Useless%2C_US_Government_Accountability_Office_Warns

"
Unless you're paying thousands of Dollars for millitary grade navigation equipment, i wouldn't spare the lag issue another thought."
Diamond1 paid £150 was spot on. No Lag. The speed indicator on tomtom was very accurate, not like on the diamond2 where it takes over 2 seconds to show a speed change. I am surprised that not many people have noticed the slow and inaccurate GPS performance of the D2.

Did i break my GPS antenna somehow?

i've been switching roms trying to get my GPS to lock back on.
i used to get it down to exactly which room I was in in my House.
i think it said accurate to 2 meters.
I could use google nav like a champ and it would lock on quickly.
now i can't get it any closer than 20 m. It seems to refresh my location slower and I have problems using google nav b/c it continuously loses my GPS signal.
Any suggestions? thoughts? people with the same problem?

Where do you live, remember weather is a significant factor when it comes to GPS. It is getting about that time of year where it is going to be cloudy and rainy a lot. We had a big rain storm come through a couple weeks back and I couldn't even get a lock in my car.

ah i was replying to this thread when XDA froze.
But i'm in southern cali and everywhere it wasn't working.
on the 101 freeway, 110, 405, highway 1
anywhere
it used to be so spot on.

Was it overcast or raining when you were having problems? I have checked the public GPS interference notices and there is nothing specified in your area and there are only 2 unavailable sats right now, although there is the slight possibility that there is something on the classified notifications that may explain any service disruption, but I doubt it. Most likely it is due to atmospheric effects, although there is also the chance that something is indeed broken, whether physically or in software. There is an app on the market called GPS status that has an interface similar to old-school garmin devices where you can see where all the sats are and your signal strength for each of them. Also, once you get it installed play around with it in different weather conditions and times of day(the signal should be stronger at night if it is clear). If you want I can do some baselines and send them to you to compare, although I am in CO, so it may be better for you to compare to someone else in CA.

I just received my new hero and it definitely was an internal problem. I can get a lock in seconds now and.within two meters.
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