GPS navigation question...

[ukcatsb4hawks]

Is it at all possible to navigate with no cellular signal? Is there an app that uses purely satellite signal like a real GPS device?

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[terpitude71]

might be wrong about this, but i think you can navigate with just a gps signal; youll just have time where you wont be able to see the map without a data signal.

if i am wrong, there is an app called co-pilot live usa that is a turn-by-turn nav app that stores all its info on your sd card so you dont need a cell sig to use it. it costs $5. not sure how it works though, as i have never had cause to use it

 

[ukcatsb4hawks]

Thank you so much!

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[cobra302]

I think if you have no cell signal you can't use google maps. I believe navigon just released a gps to sd card app as well. But not near 5 bucks. More like 40.!

 

[thegov]

You can use gps anywhere but you won't gat navigation w/o a signal. That is the difference between gps and navigation. There is a stand-alone product that was mentioned above i believe, but it is quite expensive.

 

[04redgto]

You have to be without signal for a while before no map is rendered in google nav. I have driven several trips to San Antonio (over 900 miles) And never once didn't have map rendering. and there were several occasions were I had no signal. I believe google nav buffers maps ahead. I travel all over the country, and am on the road 2 weeks a month, and I can't think of even 1 time i didn't have map rendering. Just fyi guys!

 

[jdbower]

I believe you need a signal to plot a course for Google Nav, but as long as you don't stray too far from the course you won't need a cell signal for basic navigation once it knows the route. Obviously you'll probably want to experiment beforehand.

 

[broadwayblues]

You have to be without signal for a while before no map is rendered in google nav. I have driven several trips to San Antonio (over 900 miles) And never once didn't have map rendering. and there were several occasions were I had no signal. I believe google nav buffers maps ahead. I travel all over the country, and am on the road 2 weeks a month, and I can't think of even 1 time i didn't have map rendering. Just fyi guys!

I can relate to this, I often drive through areas of Louisiana that look like they don't even have running water, much less cell coverage. Google maps always keeps me on track, providing turn by turn, but no rendered maps. Except that one time when I think my DX got too hot, and it restarted, and then since it had no cell signal, wasn't able to provide directions at all.

 

[dahlheim]

i tried to get a gps signal several times in europe, where of course i had no cell signal. i was only once able to get a gps lock, but that appeared to be with the help of the wifi i was connected to "helping" being in the google locator database. so, i vote no, you cannot get a gps lock without a cell signal.

 

[04redgto]

Of course there will have to be CDMA signal when you start a route, after that you are fine!

 

[roberte1342]

The GPS will get a lock without wifi or cellular, but it can take up to 10 minutes.
If all you are needing is lat/long/altitlude and want to keep track of where you are going from a designated mark such as hiking, etc. There is a free app called GPS Status. Put it in radar mode and set your position. It will then keep track of how far you have traveled from your mark and point the direction back. It doesn't draw a path or anything more advanced than that but. I'm sure apps better suited to that exist.

 

[anon(40376)]

Wow, that is slow, even for a cold start. When starting GPS with my BB, in the middle of the desert (NO service), it obtains a fix in about one minute (cold start), warm start about 20 seconds. For actual navigation, I only use Garmins or Trimbles for actual GPS navigation. Howeer, with my current BB, if I want to take a photo and register the GPS coordinates, I must start a GPS software prior to taking the photo. Prior to my last BB software update, this was not necessary, but something is screwed up. (One reason I'm leaving my personal BB in the basket and jumping to Android.)

Now, for an actual question. It appears from reading this thread, as you navigate using an android device (and probably true for all smart phones), Google downloads the maps required via the provider service. I didn't know that, but I guess it makes sense.

 

[Arelunde]

Check out "Car Locator" app from the Market. It's main use is to spot your vehicle when you park it and use GPS signals to track where you are in relation to the initial point. Could be used for various things. Has different screens, one of which is a radar-like sweep. At all times, it gives you North/South/East/West and the direction (with an arrow) toward your initial location (where you parked). Very cool!

Bluetooth version plug-in also available. I think it's free, but can't tell because it's installed on my X and the price doesn't show in the Market listing.

 

[roberte1342]

Wow, that is slow, even for a cold start. When starting GPS with my BB, in the middle of the desert (NO service), it obtains a fix in about one minute (cold start), warm start about 20 seconds. For actual navigation, I only use Garmins or Trimbles for actual GPS navigation. Howeer, with my current BB, if I want to take a photo and register the GPS coordinates, I must start a GPS software prior to taking the photo. Prior to my last BB software update, this was not necessary, but something is screwed up. (One reason I'm leaving my personal BB in the basket and jumping to Android.)

Now, for an actual question. It appears from reading this thread, as you navigate using an android device (and probably true for all smart phones), Google downloads the maps required via the provider service. I didn't know that, but I guess it makes sense.

If your BB did not travel a great distance and was used in the past few days prior to your trip then the GPS almanac stored in its memory is still valid and will assist in getting a lock quicker. However if you travel to another continent this data is no longer valid and a new almanac will need to be download. This process can be painfully slow. This isn't specific to phones BB/Android but any GPS device.

 

[anon(40376)]

Even traveling a great distance with the GPS device off, or having it off for a long time should not warrant a 10 minute cold boot.
The almanac data, which is generally good for several months, is available from all satellites and is the same information on all satellites; in other words, it is not satellite specific. It supplies the general location and health of all the GPS satellites. This information loads pretty quickly on a good GPS system with good clear views of the sky.

Even if the GPS has been off for a year, or traveled a great distance while off, a unit will have to do what is called a sky search, which takes a minute longer. Once the search is done, a new updated almanac is loaded, this takes seconds.

After the almanac is loaded and the GPS knows which sats to lock onto, each sat will then download the latest ephemeris data. This data is very precise and the ephemeris data transmitted by each sat is particular to that sat. In addition, ephemeris data is only good for 30 minutes. So if the time from last turn off to next turn on is over 30 minutes, it is called a warm boot, since the only information required for downloading is the ephemeris data; almanac data will still be accurate.

I have run with GPS devices long before smart phones were invented. We use them for search and rescue and I also use them for private use while traveling in many of the desert regions of the western states. Granted for SAR we use Garmins and Trimbles, both dedicated GPS devices, with Trimbles being a very high end unit, but the Garmins are just the 60CSx models.

I have never had a cold start up time greater than about 3 minutes, and that was on my GPS device that is attached to my Nikon DSLR, and that unit, like a smart phone is ok, and pretty darn accurate, but not a dedicated unit.

Granted, on my BB, the unit is turned on at least once a month or more often when I take a photo, so there are no long periods of time it is not started.

But, if you are taking over 3 minutes to start up a GPS on your smart phone, something is wrong. If you are taking up to 10 minutes with an Android, I will be greatly upset when I switch to Android from the BB. In fact, that would mean if I want to take a photo with GPS info, I have to start up the GPS 10 minutes prior to taking the photo. Not good if that is true. would be a total disaster for Android devices.

Are you sure the 10 minute statement is not just an exaggeration? Not that it matters to me.

 

[dahlheim]

i am wondering how many people who claim you can get a gps lock without wifi/cell have actually tried that. like i said, i spent a good bit of time trying this in europe and it definitely did not work. i had the phone sitting outside in the open under clear skies for over 30 minutes more than once without success.

 

[anon(19758)]

I believe you need a signal to plot a course for Google Nav, but as long as you don't stray too far from the course you won't need a cell signal for basic navigation once it knows the route.

I can relate to this, I often drive through areas of Louisiana that look like they don't even have running water, much less cell coverage. Google maps always keeps me on track, providing turn by turn, but no rendered maps. Except that one time when I think my DX got too hot, and it restarted, and then since it had no cell signal, wasn't able to provide directions at all.

+1 to these. We all know we don't get data and phone at the same time, but Google kept reading me turn by turn while I was on the phone the other day. It was kind of annoying, but I think they pre-load your route into memory to avoid screwing you if you lose data.

 

[lfotto]

I use my X hiking in the adirondacks using Oruxmaps. It works beautifully outdoing by garmin legend for maintaining track. There is no service in these areas except for the GPS satellites.

 

[dahlheim]

I use my X hiking in the adirondacks using Oruxmaps. It works beautifully outdoing by garmin legend for maintaining track. There is no service in these areas except for the GPS satellites.

was a GPS lock made while cell service was still present, and the device then taken to where service no longer existed? i'm just trying to understand how the heck these things are supposed to work. it would seem to me that aGPS somehow needs the cell or wifi location to narrow down the location before a GPS lock can be made, given the fact that a lock was impossible for me after travelling a long ways to a place with no signal (US to Germany, Germany (after again establishing a lock with the help of a wifi location) to Italy)...

 

[lfotto]

I was in airplane mode in a leanto when I started my hike on the second day. I turned on the X, ensured I was still in airplane mode, and went into oruxmaps to start track. No service was available. I did come out of airplane mode for approximately 10 seconds and it appeared to kick the GPS into operation but no service was available for phone or network connectivity. I turned it off the night before to keep battery up. With the extended battery I was able to hike the whole day and still have 50% power with GPS on the whole time to record my track.