> Not that this should come as any surprise, since the leaders in cell phones these days
> are basically Gen-Ys whose idea of "wilderness" is Discovery Park.
Who explore it via virtual reality on TV.

Cheers

"There are ways to get very high accuracy in a GPS receiver, but very few want to pay for it."

As long as cell phones provide reasonable accuracy in urban settings, that's not likely to change. I've found that even with cell signal, my cellular GPS devices have been pretty bad, in that they can't tell whether you're on I-90 or on a service road parallel to I-90, even when that service road is close to 100 yards away.

Either way, I think it's pretty certain that smart-ass phone aren't going to replace dedicated GPS devices any time soon.

"Who explore it via virtual reality on TV."

You got that right -- especially in the Fat Country. I mean, the US. ;)

"I've found that even with cell signal, my cellular GPS devices have been pretty bad, in that they can't tell whether you're on I-90 or on a service road parallel to I-90, even when that service road is close to 100 yards away."

Don't be too quick to indict the cellular GPS. It might have a fairly accurate position fixed, but the underlying map database in the device might be askew, or there might be a datum error.

I know some areas where the map database is consistently 80 yards off in one consistent direction. In other areas, the map database is almost perfect on a daily basis.

Due to the different timing technologies used by different cellular carriers, the errors can be all over the place.

--B.G.--

"Due to the different timing technologies used by different cellular carriers, the errors can be all over the place."

Either way, the end result is that GPS in a cell phone is at best, mediocre.

The end result, regardless of where the problems lie, is that I can't trust a GPS in a cell phone to give me accurate information, no matter the cause of the error.

I seriously doubt that they'll ever get it together, since most of the cellular providers are more interested in buying politicians than improving their services and infrastructure, so the quality of their lousy service isn't likely to improve.

I guess it all depends on what you want GPS to do. If it's going to be switched on all the time so you follow or record a track then smartphone batteries don't last long enough even for a day out. The best standalone GPS battery life I've come across is around 25-30 hours (Satmap Active 10 with AA lithium batteries).

However if you just switch the GPS on to check your position on when route finding is awkward and rely on a paper map most of the time then a smartphone is fine. I used one on a Pacific Northwest Trail through hike in 2010 with topo maps loaded and ViewRanger software and it was very useful many times. Switching off other stuff and just using the GPS a battery lasted 3-4 days. I carried two spare batteries.

That phone was a non-waterproof, non-shockproof HTC Desire. I carried it in a hard shell inside an Aloksak bag and had no problems on the 75 day hike. Mostly it was in a jacket or shirt pocket for quick access. There is the Motorola Defy if you want a shockproof, waterproof phone.

On any walks longer than a few days I'll take the smartphone rather than a standalone GPS to save weight. But I still do most of my navigation with paper maps - A4 printouts from mapping software not big heavy ones.

"A4 printouts from mapping software"

I print at Super A3 size. Often I need to get the "big picture" when I am out on the trail. You just can't do that with the display on a smart phone, iPad, or handheld GPS receiver.

Yes, thank heavens for lithium AA or AAA batteries.

--B.G.--

I prefer A4 for convenience - I just print out enough to have the big picture if required. I also often carry smaller scale maps too. This worked well on the PNT.

Smartphone and GPS mapping is of course limited by the small screen even if you can scroll through hundreds of miles. That's why I always carry paper maps too.

On short trips I carry big maps - UK Ordnance Survey or Harveys - that cover large areas. I wouldn't want to carry a dozen of those on a long walk though.

>> they can't tell whether you're on I-90 or on a service road parallel to I-90, even when that service road is close to 100 yards away <<

There is another issue with the phone GPS that may cause this kind of error. If the GPS software is designed to make the user "feel good" about their nice tidy display, then the GPS software may position the marker on the "nearest" road and not actually show your real position. After all, why would any GPS user ever want to see their position shown off the road? ;)

Car GPS receivers pretty well all do this because you are driving the roads, so why let the GPS marker wander? It's inacurate but works for drivers. Who knows what the software is doing with the phone GPS signal? If they are designing the software in phones to act as car GPS's then they are not ideal for off road wanderings IMO.

Some of my handheld GPS units will let me set this (lock on road) and I know it can be quite annoying if this inadvertantly gets set. When this feature is turned on, it appears that the GPS signal or maps are not accurate when actually it's the software that is screwing things up.

" I've seen the phone's claimed GPS accuracy vary wildly as I went in and out of the cell shadow of the buildings around, and in the back country it was usually a waste."

Interesting. My crapberry's (Storm) GPS location matched my Garmin's GPS while in Yosemite. I typically didn't have any cell signal when I checked the location. While it is certainly possible, I find it hard to believe that my crapberry was better at anything that other smart phones!

I've compared my HTC Desire smartphone with several GPS units and the position has always been just about the same.

As to roads I think the key is to have topo maps and GPS software on the phone. I had topo maps and ViewRanger when I hiked the PNT and the accuracy was fine. I sometimes used the phone GPS to find old trails that had faded into the bush and I found them quite easily every time.

Maybe phones have improved more than I'd realized... On my last phone, a Samsung crapform, I was lucky if it even locked a signal inside of half an hour, and its navigation actually got me lost once in a neighborhood I wan't familiar with.

Ask and you shall receive Bad Elf make a external antenna for the ipod Touch and iphone for $99.00.
I was thinking of geocaching to stay in shape around my town hiking and finding the 100 plus geocahces. Apple even has apps that you can save off line maps and hints for ipod touch,iphone in place you get a wifi or cell reception. Their is also off line mapping apps.

http://bad-elf.com/products/gps/

The only reason I have not not purchased it is because the glass touch screen I am worried about breaking if I drop it,I own a Griffin strongest ipod touch case approved for military use.

On the solar energy assist recharging it really has to have a advanced solar high amperage technology that will be fully charged in cloudy conditions in a 3 to 4 hours. Compared to the cheap solar chargers on flash light used now that takes 8 to 10 hours in direct sunlight. Rechargeable battery charging system on the phone that does not damage the batteries from being charged constantly during charging. Then I will purchase one.
Terry

Edited by socal-nomad on 01/22/2012 09:30:09 MST.

Terry, that is _not_ an external GPS antenna. That is an incomplete GPS receiver as we discussed above.

--B.G.--