# GPS unit, does yours take a long time to get a signal? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [October 23, 2006, 6:01pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597 "2006-10-23T18:01:15Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![SweetHomeColorado](https://avatars.discourse-cdn.com/v4/letter/s/d26b3c/32.png) [@SweetHomeColorado](https://boards.straightdope.com/u/SweetHomeColorado)\ **Post date:** [October 23, 2006, 6:01pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/1 "2006-10-23T18:01:15Z")
I recently purchased a GPS system from Fry’s electronics for about $200. They had a great sale so I figured why not. The unit I bought is the Findrive 350… Obviously not the top of line. Does anyone have any experiences with the Finedrive? If so, does yours also take a few minutes to obtain a signal? Is this common with GPS units? It will get a signal, then lose it, then get it back. It’s somewhat frustrating. I’m wondering if it’s my particular unit or if this is usually expected from GPS devices. If it’s a flaw in the unit, I’ll obviously send it back for a new one that receives a better signal. Any other words on the finedrive? ---
**Author:** ![Moirai](https://avatars.discourse-cdn.com/v4/letter/m/96bed5/32.png) [@Moirai](https://boards.straightdope.com/u/Moirai)\ **Post date:** [October 23, 2006, 8:21pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/2 "2006-10-23T20:21:07Z")
Huh. Mine is built into my car, so I’m not sure of the device maker, but acquisition of signal is usually very fast. Sometimes it takes a few seconds, but that’s the exception. ---
**Author:** ![Omegaman](https://avatars.discourse-cdn.com/v4/letter/o/e480ec/32.png) [@Omegaman](https://boards.straightdope.com/u/Omegaman)\ **Post date:** [October 23, 2006, 8:39pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/3 "2006-10-23T20:39:50Z")
Mine’s built into my vehicle as well. Seems to work quickly though I have only used a first generation handheld GPS to compare it with. ---
**Author:** ![monstro](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@monstro](https://boards.straightdope.com/u/monstro)\ **Post date:** [October 23, 2006, 8:50pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/4 "2006-10-23T20:50:47Z")
I have a hand-held Garmin. It takes about a minute to get a signal after I turn it on. Only rarely does it lose a signal, and that’s usually when there’s forest cover around me. ---
**Author:** ![Jet\_Jaguar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jet_jaguar/32/3562_2.png) [@Jet\_Jaguar](https://boards.straightdope.com/u/Jet_Jaguar)\ **Post date:** [October 23, 2006, 10:42pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/5 "2006-10-23T22:42:00Z")
I have a Garmin Quest, which I use in the car and on the motorcycle. It normally takes about a minute to get a signal, but I find if I turn it off and then turn in on again in a very different location (say, if I fly across the country for work and bring it with me), then it may take a little longer. It never loses the signal unless I’m in a tunnel or stopped under an overpass or something. ---
**Author:** ![11811](https://avatars.discourse-cdn.com/v4/letter/1/9d8465/32.png) [@11811](https://boards.straightdope.com/u/11811)\ **Post date:** [October 23, 2006, 10:55pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/6 "2006-10-23T22:55:22Z")
I use a Garmin, and it takes some time, but I’m biking in the city of Philadelphia when signal acquisition begins. By the time I’m on Kelly Drive, I usually have achieved the signal. ---
**Author:** ![capybara](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/capybara/32/202_2.png) [@capybara](https://boards.straightdope.com/u/capybara)\ **Post date:** [October 24, 2006, 12:35am UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/7 "2006-10-24T00:35:21Z")
I have a Garmin and it takes a while to get enough signal-- 2 impatient minutes or so (if you look at that screen you can see it’s trying to get 5+ satellites, and preferably close to the horizon and spread out) but I’m often in mountains/ trees. I lose the signal often for the same reason. I think it’s to be expected. ---
**Author:** ![Thalion](https://avatars.discourse-cdn.com/v4/letter/t/f475e1/32.png) [@Thalion](https://boards.straightdope.com/u/Thalion)\ **Post date:** [October 24, 2006, 8:16am UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/8 "2006-10-24T08:16:04Z")
I have a Magellan Gold hand-held. It usually takes about a minute to get a lock, and almost never loses the signal. The signal may degrade some under heavy trees so that the EPE gets pretty large, but it’s very rare that it loses the signal completely. ---
**Author:** ![scareyfaerie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scareyfaerie/32/3135_2.png) [@scareyfaerie](https://boards.straightdope.com/u/scareyfaerie)\ **Post date:** [October 24, 2006, 8:24am UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/9 "2006-10-24T08:24:47Z")
I have TomTom on my PalmPilot, it’s usually not too bad for signal acquisition although sometimes it’s taken nearly 20mins to acquire properly. Most times I just turn on the receiver thingie and by the time I’ve faffed about getting the car off the drive and onto the road, I’ve got a signal and my Sean Canary voiceskin is trying to tell me I’m going the wrong way. ---
**Author:** ![VunderBob](https://avatars.discourse-cdn.com/v4/letter/v/839c29/32.png) [@VunderBob](https://boards.straightdope.com/u/VunderBob)\ **Post date:** [October 24, 2006, 11:50am UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/10 "2006-10-24T11:50:29Z")
Assuming you are in an area where the unit has unrestricted view of at least three satellites, you can assume that it will take 5 minutes as an upper bound to acquire the first satellite, and 20 minutes to generate a good position fix. This is a limit imposed by the algorithm, not any one brand of unit. In real life with good visibility, the times to acquire the first satellite and a positional fix are a lot shorter; on the order of 2 and 10 minutes respectively. ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [October 24, 2006, 1:24pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/11 "2006-10-24T13:24:28Z")
The fist time you turn one on, or if it has been a while or it has been moved it takes longer in general to get a fix. Poor conditions also don’t help. Brian ---
**Author:** ![Fat\_Chance](https://avatars.discourse-cdn.com/v4/letter/f/8baadc/32.png) [@Fat\_Chance](https://boards.straightdope.com/u/Fat_Chance)\ **Post date:** [October 24, 2006, 4:38pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/12 "2006-10-24T16:38:53Z")
[QUOTE=VunderBob] Assuming you are in an area where the unit has unrestricted view of at least three satellites, you can assume that it will take 5 minutes as an upper bound to acquire the first satellite, and 20 minutes to generate a good position fix. This is a limit imposed by the algorithm, not any one brand of unit. In real life with good visibility, the times to acquire the first satellite and a positional fix are a lot shorter; on the order of 2 and 10 minutes respectively. [/QUOTE] Huh? That is way to long. I use a bluetooth GlobalSat BT338 with Sirf III chipset reciever. It gets a signal within 10 seconds if in the same location as where I turned it off, and 30 seconds if in a different. I actually leave it in my glove compartment and never lose signal (unless in a tunnel or something). There are definately differences among brand/price - go with the latest Sift III chip for best results, though I think Sirf IV may be out now as well. ---
**Author:** ![simster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/simster/32/1047_2.png) [@simster](https://boards.straightdope.com/u/simster)\ **Post date:** [October 24, 2006, 4:45pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/13 "2006-10-24T16:45:59Z")
It really depends on a number of factors… not to mention that there is some “startup time” for the software itself. I’ve run Garmins, Lowrance and now Humminbird(s) in my boats for several years, those with external antennas usually do a little better, and a ‘clear view of the sky’ is a must. Still takes on average 30-60 seconds to get it all set. I’ve rarely ever seen it faster than that. ---
**Author:** ![Moirai](https://avatars.discourse-cdn.com/v4/letter/m/96bed5/32.png) [@Moirai](https://boards.straightdope.com/u/Moirai)\ **Post date:** [October 24, 2006, 6:53pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/14 "2006-10-24T18:53:07Z")
Trees and tunnels affect reception? Not on my unit. Hell, I can turn it on in an underground parking structure and it acquires the signal almost as quickly as if I was on the roof… WTF? ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [October 24, 2006, 7:06pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/15 "2006-10-24T19:06:15Z")
I have a Garmin StreetPilot which is a plug-in portable, and it takes 30-60 seconds to boot up. It takes longer if satellite visibility isn’t good. [QUOTE=EJsGirl] Trees and tunnels affect reception? Not on my unit. Hell, I can turn it on in an underground parking structure and it acquires the signal almost as quickly as if I was on the roof… WTF? [/QUOTE] :dubious: Are you sure it’s actually acquiring a signal? Or just showing you the last location it knew about? I consistently lose signal in tunnels, heavily treed areas, and downtowns with numerous tall buildings. The signals used in GPS need line-of-sight. Next time you’re in a garage and you think you have a signal go to the view on your device that shows what satellites you are receiving and what their signal strength is (I don’t know if all devices have this but mine does). From [Garmin’s site](http://www.garmin.com/aboutGPS/): > [@](#): > > GPS satellites transmit two low power radio signals, designated L1 and L2. Civilian GPS uses the L1 frequency of 1575.42 MHz in the UHF band. The signals travel by line of sight, meaning they will pass through clouds, glass and plastic but will not go through most solid objects such as buildings and mountains. ---
**Author:** ![CrankyAsAnOldMan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crankyasanoldman/32/11670_2.png) [@CrankyAsAnOldMan](https://boards.straightdope.com/u/CrankyAsAnOldMan)\ **Post date:** [October 24, 2006, 8:40pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/16 "2006-10-24T20:40:36Z")
My Garmin Nuvi 350 takes awhile sometimes, but I’ve never timed it. Enough so that I sometimes get crabbily impatient, though. ---
**Author:** ![Moirai](https://avatars.discourse-cdn.com/v4/letter/m/96bed5/32.png) [@Moirai](https://boards.straightdope.com/u/Moirai)\ **Post date:** [October 25, 2006, 1:37pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/17 "2006-10-25T13:37:35Z")
[QUOTE=CookingWithGas] Are you sure it’s actually acquiring a signal? Or just showing you the last location it knew about? I consistently lose signal in tunnels, heavily treed areas, and downtowns with numerous tall buildings. The signals used in GPS need line-of-sight. Next time you’re in a garage and you think you have a signal go to the view on your device that shows what satellites you are receiving and what their signal strength is (I don’t know if all devices have this but mine does). [/QUOTE] Ah, I hadn’t thought of that- it may be powering up where it thinks I am… ---
**Author:** ![Jet\_Jaguar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jet_jaguar/32/3562_2.png) [@Jet\_Jaguar](https://boards.straightdope.com/u/Jet_Jaguar)\ **Post date:** [October 25, 2006, 4:57pm UTC](https://boards.straightdope.com/t/gps-unit-does-yours-take-a-long-time-to-get-a-signal/377597/18 "2006-10-25T16:57:57Z")
[QUOTE=EJsGirl] Ah, I hadn’t thought of that- it may be powering up where it thinks I am… [/QUOTE] Plus, some models have backup inertial navigation systems so it can still give you some idea of how you’re travelling even when it can’t recieve a GPS signal. Drive through an underground garage and the unit can sense the accelerations of the vehicle and still plot something reasonably resembling your course.