GPS, GLONASS and the Iphone 4S

[sthughes]

I was just browsing through the specs for the Iphone 4S and noticed under "Location" that it uses "Assisted GPS and GLONASS". I had never even heard or GLONASS before but apparently it is the Russian equivalent of GPS (GLObalnaya NAvigatsionnaya Sputnikovaya Sistema).

Apparently what this means is that the Iphone 4S should be able to look for almost twice as many satellites in the sky compared to the vast majority of GPS receivers. On top of that the GLONASS network reportedly works better at the extreme north and south latitudes, due to the orbit of the satellites.

I just thought this was pretty cool for bushwalkers! Down in gullies and under trees where GPS is a bit hard at times and this should help.

Apparently some Sony Ericsson phones and a couple of new Samsung Tabs/phones also supports it, as does the new Garmin eTrex lineup.

All you gear freaks with more than 6 month old GPS units bedda get out and replace them

[photohiker]

All you gear freaks with more than 6 month old GPS units bedda get out and replace them

Dayum!

I was just looking at my Vista HCX. Bought in March 2008 for $240, so $60 per year. Still works great. I'll wait for the reports of amazing performance improvements before I trade out this trusty little unit.

[Ent]

So have you installed it and will it beat the Garmin 62S?

Cheers

[tasadam]

That would explain why the GPS thingy in the phone works so good, no matter how far indoors I se to be. The eTrex's favourite message is Are you indoors now?
iPhone 4s says I don't give a "rats" whether you are indoors now.
It's impressive enough, despite my app based custom signature...



Sent from crap electronic device using dodgy app.

[Ent]

Hi Tasadam

Could it also be it is using the phone towers to triangulate your position?

Cheers

[stepbystep]

I wouls suspect the battery life would be the prohibative issue, can you carry a spare for an iPhone?

[Ent]

Plenty of battery plug in packs and even a few cases. One I am waiting on is water resistant, big battery and solar charging. Not so sure on solar charging working well but the rest sounds good.

Sthughes is the "expert " main issue is GPS and phone must be on together do on poor reception areas the power consumption is high.

Cheers

[Son of a Beach]

You don't need the phone to be on at all to get accurate GPS readings. It is just a lot quicker when the phone is on and can take a loooong time to start producing results if the phone is off.

When out bush I disable the phone and WiFi completely to reduce battery drain and the GPS takes longer to get a result but it's perfectly accurate eventually. (Phone disabled by setting a SIM PIN and restarting the phone. Clumsy but it works).

Note that some silly apps may not show your location if the phone is off due to being unable to find a network to download map imagery from. But that's a problem with the apps. The GPS data is still produced just fine.

[Ent]

Hi SOB

Clever thinking and nice hack. I might have thought that the phone would be looking for towers for emergency calls but then again will not be transmitting "hi am here" signals which is normally the power hog.

What sort of battery life do you get in that mode?

Cheers

[Son of a Beach]

Yes as soon as I posted I remembered that it does still have SOS mode when there is a network available. Presumably the GPS may still be assisted then too? Not sure.

I'm sure I've had much improved battery life that way but haven't used it much for a long time and didn't really document the results.

[Ent]

Hi SOB

No problems just curious as having the Tasmaps on the iPhone is great as Sthughes does that. The Garmin maps are well arh let's say not up to standard for bushwalking.

O'well keep us informed on progress.

Cheers

[Son of a Beach]

I did a web search that indicated nearly 1% of battery per hour can be saved by removing or disabling the SIM. That's quite substantial.

[stepbystep]

I like the idea of decent maps, but I'd carry the paper version regardless, are you not worried about water/shock issues?

[Ent]

I like the idea of decent maps, but I'd carry the paper version regardless, are you not worried about water/shock issues?

Hi

I always regard electronic devices as additions to tried and tested means. Maps can be blown away and soaked thru so still not perfect.

After the brilliant performance of Sthughes iPhone on the WA plus nice having music at night the iPhone will likely become another bit of weight.

Might have to drop a light or three! Now I know why I brought the MSR Nook!

Cheers

[Son of a Beach]

Paper maps are clearly more reliable as far as just maps. But being able to use a mapping GPS which automatically shows your location on a map, or automatically shows where you've been, is fun. It can even be useful.

[Nuts]

Ive had mine on a few walks now. GPS does seem pretty good. Iv'e found caching map tiles works fine with everything shut down. As far as power goes ive read of people removing the sim, not sure why , powered down it seems to not use any... remembering to power down is another matter. Battery heavy if using for several things (photos, email, web stuff) but the trent battery (SBS) will charge it a couple of times and seems reliable (power phone down before leaving it to charge othewise it will spring to life every time a message comes in or junk mail lands)

I havent worked out how to place and 'go to' a waypoint on GPSkit or if its possible but tend to only check GPS now and then anyhow.

I'd imagine for real heavy users (ie off track and close navigation) a dedicated GPS would still be a better option weight for weight. Perhaps some GPS also use GLOSNASS?
I did notice the GLOSNASS listed somewhere in the iphone research, how many and how functional?? but it is quick and seems accurate..


sent from home... at last!!

[Nuts]

O.. they fit neatly in a mini zip lock and remain useable but turn off the proximity sensor...

[photohiker]

I did a web search that indicated nearly 1% of battery per hour can be saved by removing or disabling the SIM. That's quite substantial.

Is it really?

Mine is a 4, not a 4s. I get 2 days out of a charge which includes at least 2 hours of GPS use, not a lot of phone calls and some browsing/email/messaging.

Saving 1% per hour isn't going to make a worthwhile difference. 1% per hour is going to save 8% on an 8 hour walking day. Even then, the phone will struggle to make it through 2 walking days using GPS constantly. If I turn the phone off when I didn't need it, I could (and have gone) for a week on a charge.

On the other hand, the Etrex takes AA batteries, and goes for a couple of days (20+ hours use, I usually get 3 whole days walking) per pair of batteries while being left on, tracking the whole time. Newer Etrexs seem to be not as economical, looking at specs.

No contest. Dedicated, waterproof, replaceable batteries, on board mapping. I like my smartphone, but I use it as a backup for GPS not a replacement. Some of the other smartphones have replaceable batteries, but I think you might as well just buy something built for the job.

[tasadam]

While not entirely relevant to this topic, I thought I'd mention...
I've recently fair hammered my iPhone for continuous usage. While not making any calls or SMS through Telstra, I used a fair bit of data and the screen was lit up all the time, at a brightness level a bit under half.
I found the battery to go from 100% to 1% in about 4 hours.
it's a 4S less than 2 months old.
That was using data, but not using much (if anything) with the GPS, most of the "share your location with this app" stuff is turned off.

With that battery performance, I'd certainly want at least 1 of the external power bricks for the iPhone.
I've read there are some that do 7 hours of talk time, but the only statistic missing from the description was weight.


Sent from crap electronic device using dodgy app.

[sthughes]

Yeah I've tried the SIM lock but found it was always searching for network anyway (better but still uses battery) and also a pain that if you want to use the phone for anything you then have to do a hard shut down and restart to turn it "off" again.

I don't use it for tracking much as it uses far too much power. So instead on longer walks i run it on airplane mode and just switch to normal to check position from time to time. Also means you can easily check for reception. I have 5 external batteries of various types.

Have also found the 4s eats battery power for a few days after you drop it in a river. I suggest dropping it in a river on the last day of a long walk, not the first.

[Ent]

Hi Sthughes

But it did still work and got a message out when other phones did not. Though now I know why your are now looking at dried rice dishes.

Any power saving is pretty good and worthwhile as the last few percent can mean call in and out that otherwise would not happen.

My Garmin claims 20 hours continuous use and that is 3100 maH batteries at 3 volts so the iPhone does well given its battery. The question for me is the power loss charging the internal battery. If it was say 50% then your battery pack would need to be twice the size of the inbuilt battery.

Be good to compare tracks between the Garmin 62s and iPhone. The Garmin works were more than a few other GPSs struggle.

Cheers

[Son of a Beach]

Just to clarify... no setting a PIN on the SIM is of no use if you power down you phone when not in use anyhow.

The only time when it is of real use is if you are using GPS tracking to record waypoints along the way. NB: This is a very power draining thing to do in most iPhone apps anyhow, as most of them will leave the GPS powered up the entire time, and this can drain your battery in just a few hours flat.

Some apps actually power up the GPS only periodically (ie, when actually ready to record a waypoint) even when running in the background. It is with these types of apps that it is worth running the GPS with the phone disabled. You can actually get a couple of days worth of continual tracking out of it this way. Several days if you power down the entire device when not actually walking.

I agree with those who say a dedicated GPS is better. But for myself, I rarely use any GPS (phone or dedicated). I've never owned a dedicated GPS, and have no plans to every buy one. I've never had the need for one. Most of the time I'm happy using a map and compass, and now that my phone has a mapping GPS, I can use it as a backup occasionally if I have to (and if the battery hasn't gone flat). Of course, if I was on a walk where I thought there might actually be any navigation issues, I would leave the phone switched off until the time came that I actually did need it. I used it this way on the Franklin River. Turns out I didn't need it, but was able to check my position occasionally on the map using the iPhone, and it still had plenty of battery power left after 14 days. For my own usage patterns, buying a dedicated GPS would be a waste of money. I have to have a phone for work, and it does more than I need in terms of mapping and GPS.

[sthughes]

Some apps actually power up the GPS only periodically (ie, when actually ready to record a waypoint) even when running in the background. It is with these types of apps that it is worth running the GPS with the phone disabled. You can actually get a couple of days worth of continual tracking out of it this way. Several days if you power down the entire device when not actually walking.

Cool, which apps will do that?

Brett perhaps we will have to have a "GPS Off" between the Garmin 62s and Iphone 4S! Actually you have both, why don't you go for a walk around Launceston for us - under some shop awnings, through City Park, out in the open.... I suspect the Garmin will still have the edge, I mean the antenna itself is half the size of an iPhone!

[Ent]

Hi

One of the great advantage of a smart phone is the ability to use Tasmap so you can check easily between the phone and the printed map to solve debates over what feature name is that. Hint, just because it is the tallest mountain that you can see does not mean it is Ossa.

Have found that using 100,000:1 maps even with a gps you can not be precise enough to pick obscure track junction points so the on ground skills are needed plus dumb luck does not go astray either.

To be honest most use for my GPS is checking after the walk the distance covered and elevation gained/lost to measure my physical efforts for planning other walks. Especially good with never people as planning a walk with new people it helps to have an idea when you will arrive so can go to plan B or C.

I think most people tend to follow their nose and only use maps/gps when checking progress and if rather confused. This means for me on most walks a gps sits unused apart from been a data logger. Actual a watch with a altitude measure is usefull for gauging where you are.

But if visibility drops or in scrub a gps is a nice thing to have also for marking points of interest. On the WA wander a group had come in off track and used a GPS to find the start in a gap in cliffs that is used to go that way. A gps gives the pin point precision in dense bush that saves a lot of mucking around.

Cheers

[Nuts]

Are you guys accessing TASMAPS online or through a GPS app??

[Son of a Beach]

Some apps actually power up the GPS only periodically (ie, when actually ready to record a waypoint) even when running in the background. It is with these types of apps that it is worth running the GPS with the phone disabled. You can actually get a couple of days worth of continual tracking out of it this way. Several days if you power down the entire device when not actually walking.

Cool, which apps will do that?

Bit Map, of course! Although it's not perfected yet. Doesn't always work as expected. You also have to set the waypoint interval to greater than 5 minutes, I think it is.

Apple have allowed three different ways for app developers to use location information in an app running in the background, but unfortunately, NONE of them are suitable for tracking accurate waypoints periodically. They either require the GPS to be always powered up, or to use very inaccurate positioning. However, there are one or two sneaky tricks that app developers can use to work around this.

Bit Map attempts to use the always-on-always-tracking method to be allowed to run in the background (only when waypoint recording has been turned on by the user). But once a waypoint has been recorded, and if the time between waypoints is set to 5 minutes or more, it sets its required accuracy temporarily to 30km. In theory, this should disable the GPS, and allow the device to use its other lower-power location sensing components (eg, phone). When the time comes for Bit Map to take another waypoint, it sets the required accuracy back to "best" and waits until it gets an accurate reading before recording the waypoint (and then sets it back to 30km again). It only does this weird behaviour when running in the background, in order to try to save battery power.

[sthughes]

Nice hack Nik, might have to try it out again sometime

[LandSailor]

My fave use of the GPS is to mark significant waypoints that I can plug in the coords to Google Earth after a trip. I can really make good sense of the terrain that way.
I mainly use EveryTrail which does everything I need including the ability to pre-download offline maps.
I will check out Bit Map as well, thanks for the tip.

[walkinTas]

My fave use of the GPS is to mark significant waypoints that I can plug in the coords to Google Earth after a trip.

+1

I like to stand at the top and base of waterfalls and mark the spots. My Explorer 500 isn't always the most accurate, so I can't totally rely on altitude, but it is a bit of an indicator of height.

[sthughes]

Are you guys accessing TASMAPS online or through a GPS app??

I use Memory Map Free. You can purchase all the 1:25000 and 1:100,000 Tasmaps for about $80 from memory, some of them are a bit out of date but you can use them on two mobile devices simultaneously (iPhone & iPad for example). Works well, I export tracks. waypoints etc. to .gpx to share.