Last resort to try to figure out my GPS problem. Can anyone help?

[Snoking]

The gps in these phones are what is called an assisted GPS. They need a 3G connection to first lock onto the sats. Once locked on, they will remain locked on as long as the GPS is on. Take a hike away from the cell towers and sit on top of a mountain with a clear view of the sky. GPS will NOT work.

 

[RETG]

I'm assuming the X is using e-gps, or is it using only gps?

 

[Bear in NM]

Snoking,

Are you refering to the X specifically (the OP's phone)? My droid 1 has no problem getting a gps fix without a data connection, as I have done so more times than I can count, and just tested it again. I use an offline mapping program (oruxmaps) for work that has been spot on without a data link, countless number of times.

If the X uses only Assisted GPS then this could indeed be the OP's problem, and would be a serious design flaw in the phone.

Craig

Edit; here is the official spec sheet: Looks like a and s gps so the op's phone should work standalone, as the Droid does. But the spec sheet does footnote and say "network dependent feature" so who knows.

http://www.motorola.com/Consumers/U...s/Mobile-Phones/ci.Motorola-DROID-X-US-EN.alt

 

[FunN4Lo]

X2 3g is NOT needed to get a GPS fix. I just posted in a thread a few days ago starting turn by turn navigation with no cell signal 3g, 1x or otherwise. I use navigation everyday and I have not had issues like the op, but I have had occasional no fix problems. Maybe a coincidence, but I have not had any issue for a month since turning on Latitude

 

[Snoking]

Put your phone in airplane mode and tell me your gps will lock on!

 

[FunN4Lo]

Put your phone in airplane mode and tell me your gps will lock on!

I just did, as I have done many times, and it does. I get the blue lock arrow on the map. Now if I was in airplane mode and flew across the country and tried to get a lock with out turning airplane mode off, I would not get a map. But if you have a cached map, the app will use it.

 

[Bear in NM]

You are correct, airplane mode will yield no gps lock. But this does not simulate normal phone operation (non-lock down mode), quite like just turning off 3-g, or better yet being in a location where you do not have 3-g. Again, on my Droid 1, I do not need 3-g to get a gps fix. This was confirmed on day one with my droid, as it is one of the phones most important features for me.

Craig

edit; I only tried the airplane mode for a couple of minutes with no lock, so per the next post I am mistaken about airplane mode, only.

 

[Snoking]

OK, put your Droid in airplane mode with GPS off reboot the phone and open GPS Status. NO LOCK. Turn on GPS manually, NO LOCK. Turn Airplane mode off and GPS locks right on. For the Droid GPS to lock on, it needs a 3G signal. It will then lock on as long as the close location it stored in the phone. It is not a relievable GPS to go hiking in the mountains with!!!!!!!!! Just try what I posted above. This has been covered in other threads. If you are using your GPS a lot, then you will most likely not see this issue. But it does need network for its first lock on.

For the OP, maybe this is your issue. How often do you reboot your phone. Are your GPS problems related to location and a reboot?

Chris

 

[Bear in NM]

First, let me say that I am not being argumentative about the lock. I find this intersesting, as I know at our ranch, which is 50 miles away, I have no data connectivity at all. I also know that my phone has been off for trips over there, with me turning on my GPS to use my Oruxmaps program.

I ran a test in the few hours since the last post. Turned off the data connection on my phone under settings/networks. We then went across town which is about 20 miles away, and had lunch. This was approximately 3 hours from the time I turned the phone off, so I am pretty sure I was not seeing the exact same satellite constellation. I powered on the phone, left data turned off, and then toggled on GPS. When I went into GPStatus, it took all of about 10 seconds to get gps lock. Turned the data back off, powered off the phone and came home. Again about 10 seconds to get lock.

So, if it is a distance thing, I have yet to reach it. I will admit to only turning of data not using airplane mode, so perhaps my phone was still being tracked in some way that I am unaware. I will certainly be testing this more as hunting season is fast approaching, but so far I have not been able to duplicate lack of lock under the situations I have posted above. And as I am running 2.2, is it possible things are different from the old GPS posts and 2.0 and 2.1???

Craig

 

[RETG]

The sats may have changed, but the almanac information you downloaded the last time the GPS was turned on, still retains the locatons and future locations of ALL satellites in the GPS network.

A GPS unit must be turned of for quite some time, talking days, and moved quite a distance, talking hundreds of miles, before the contained almanac information is no longer effective. So a lock from a few miles and a few hours is not a problem, or at least should not be a problem.

When you first turn on the GPS in needs to download or verify that the almanac information is up to date. Almanac info tells the GPS where each satellite should be in the sky and each sat has information on all other sats.

After that is updated or verified, it needs more specific information from each satellite. That's when the Ephemeris data is downloaded. This information, good for only 30 minutes, is very precise for each sat and that information for each sat is contained only by that sat.

The Droid X, per Motorola, has assisted GPS. With assisted GPS, the network assists the satellites by supplying a triangulation for the phone to lock onto, if you are in areas where GPS has a problem locking onto the sats. Normally, this is due to a low power GPS device such as a cell phone. Dedicated GPS devices or those run by vehicles, can use high power for the receivers to allow them to be more sensitive.

I also believe with assisted or enhanced GPS, the towers keep the Ephemeris data updated for the sats that can be seen from those towers. It then broadcasts that info to the cell phone.


I know my BB Tour, in Verizon 3G area, is actually more accurate than my Garmin 60CSx. That is with a clear view of the sky. In a heavily treed area, the Garmin exceeds the BB. But under the clear sky, outside my door in the desert, the BB is more accurate. I'm talking feet so either should get you home if needed. (Many might ask how I can determine this, well, I have use of a Trimble system with 10cm accuracy.)

However, if I head out of Verizon's 3G coverage area to the desert, the Garmin now becomes the most accurate. The BB Tour still locks onto sats, and still give me a good position fix, but it is off by a few feet. Out of the 3G area, it has no towers to triangulate with so the accuracy is based totally on the receiver contained inside the phone.

I sure hope the Droid X is not dependent upon the network to work. Per Motorola it is not, since they state it is ASSISTED GPS. However, they might be running a very low power GPS receiver inside the phone, which might just cause problems.

Then again, there might be some very screwed up phones out there, or the software for the GPS receivers is defective.

 

[Bear in NM]

Thank goodness, another Land Surveyor to help here. I go back to the very first days of commercial gps use, back when we had to work at 2 or 3 in the morning to get four satellites, and were darned excited to do so.

Sounds like you have some specific knowledge of almanac and ephemeris info on cell phones. I had mentioned this, but could only speculate based on experience. And the fact that I could not fathom a different way that the system could work, other than perhaps your mention of the towers storing this data and broadcasting, perhaps in a way similar to Waas.

I followed all of the early threads on how the unit would not work without data, and was pretty perplexed as I never saw that. I think that much of the confusion may stem from the fact that folks are using airplane mode to simulate lack of 3g when likley airplane mode is doing something more to the gps reciever side. I also know that there are folks using apps designed for airplane use, which clearly means the planes have no cell tower communication while in the air. Surely they can get assisted gps while at their airport, but once in the air if the phone were unable to regain lock after a power off, this could be very problematic to say the least.

Now for a total hijack, Retg, have you tried the oryuxmaps program on the phone. When used with the mobile atlas creator program, you can download and store map sets on your phone for use without data coverage. The mobile atlas creator has a pretty broad data base of maps to choose from, including Google Maps and the Fed. terra server. As you likley know, the Terra server gets you 7.5 minute quadrangles, and I have confirmed that the georeferencing and plotting is at least as accurate as the recievers/phones appear to be. Very cool for those of us in the public land system, or for other folks like myself who have been totally frustrated with commmercial recreational gps and 1:100000 resolution. And the oryuxmaps allows full integration of waypoints and routes from your other gps devices via the gpx format.

Craig

 

[RETG]

Sorry, not a land surveyor. I don't use GPS to mark the land, I use GPS to stay alive and to sometimes, save lives.

Have not tried oryuxmaps, but then again, I am still using a BB Tour, waiting to hear from Verizon to find out if I can update 3 months earlier to a Droid X.

 

[Snoking]

Some threads to read:
http://www.droidforums.net/forum/droid-general-discussions/61555-droid-gps-agps.html
http://www.droidforums.net/forum/te...13-gps-possible-droid-without-3g-service.html

I think maybe there is a bit of confusion here. The Droid requires a CDMA cell tower connection for the inital GPS lockon. Google Maps require 3G data connection.

Conclusion is do not trust your life in remote area's on a Droid GPS to help you find your way home!

 

[Snoking]

BTW, if you watch the "last fix" on the GPS status app you can go into airplane mode and still see last fix updating, so airplane mode DOES NOT turn off the GPS. Chris

 

[Bear in NM]

RetG,

Good luck with the upgrade. And I am not sure which maps you like to use for your line of work, but the Mobile Atlas Creator program seems to have pretty robust development, and you might find a map set/type to help when you are remote. And it sure is nice to be able to layer satellite imagery, terrain, or topography that is way more useful than 1:100000 resolution/scale.

Chris,

Well, not really any confusion, just a little disagreement about how the GPS works. I have followed every Android GPS thread here (including your links), and all I am saying is that I can get lock without a data connection. Certainly when you factory reset the phone, perhaps CDMA is needed, but my experience runs contrary to all of the folks who say you need 3G to get a GPS fix. No question that you would need 3g for navigation or maps, but my comments above about Oryxmaps means that I do not need 3g for that mapping program.

There is a little saying by one of the top shooting instructors in the country. 2 is 1, 1 is none. Anyone who ventures into the back country, depending upon electronics to keep their life save, better have a backup plan. Like a map and compass, and basic orienteering skills The Droid would suck as a primary device, as it is not weather proof, it is relatively fragile, and is harder than heck to see in bright sunlight. Can't be used effectively with gloves, has a pretty narrow temperature operating window (wildernessly speaking), and has a miserable battery life, compared to a handheld GPS reciever that can run 24 hours m/l with double A batteries that you likley have a lot of spares for things like flashlights or headlamps. On this point we most certainly agree.

Craig