UKH

I'm thinking of getting a GPS device for navigation on the hills, and am guessing that the obvious way to go is to go for a smart phone. I neither want nor need a new phone, perfectly happy keeping things old school, but if it's better simply in terms of use as a GPS then I may as well eh?

My question though is this; what are the advantages (if any) of a stand alone GPS?

My particular concerns are:
Durability and ease of use in poor conditions
Reliability
Accuracy
Battery life
Cost

Any thoughts?

In reply to GerM:


Why? It's probably the last thing I'd consider!


Think you might already have answered that...

In reply to GerM:

I got a second hand gps for £30 on the forums. Only ever use it in fog etc. Just sits in my bag waist pocket to check coordinates. I find it too much faff to plug coordinates in etc.
much better using a map and using it to check. That way when you break/drop/runs out of batteries you still know where you are and where you're going.
I tried a phone one but just drains the battery too much then you can't take lovely pictures!

In reply to GerM:

Durability/weather resistance and battery life are the two mains issues with mobile phone as GPS.

Accuracy may be marginally reduced on a phone, due to compromises in the antenna design and placement.

One other issue you haven't mentioned is sunlight readability of the display. A typical smartphone uses a backlit display (one reason for the poorer battery life), and may be hard to read in sunlight. Old skool GPS receivers may use a transflective display, relying on ambient light, with a small backlight for night use.

In reply to GerM:

Plenty of advantages to a dedicated GPS unit over a mobile phone, esp if you don;t actually need a new phone! I've compared my last 2 phones (HTC Wildfire and Nexus 4) to my garmin unit, and the garmin was substantially more accurate and reliable. Some really obvious spikes/jumps where the phone has lost signal etc and a few glaring errors where it had me swimming through lochs and walking over seacliffs too.

1) Cost, particularly if you don't need a mapping device (i.e. one that displays a OS style map) will be MUCH lower.
2) Battery life; a stand alone GPS unit's batteries tend to last a lot longer than a smart phone's. Plus given most work off either AA or AAA batteries they are easily replaced / changed on the hill and spares can double up with those for your headtorch.
3) Crap weather. GPS units will be waterproof to various degrees. Certainly they will withstand being dropped into water if recovered quickly. A mobile phone will struggle with wet and cold. Touch screens in particular are terrible in the cold.
4) Accuracy. £ for £, a dedicated GPS unit will be more accurate. A cheap smartphone won't perform as well as a cheap GPS unit, and will still cost several times as much! Mid to top range phones will have a decent GPS but cost of the phone ramps up.
5) Redundancy. Having burned through your phone battery by switching on your GPS after you get lost, you're then stuffed for making any emergency / non emergency calls....

You can buy extra battery backs, tough cases, stilus pencils etc to try and even these aspects out, but it's more money, and more hassle.

If you already had a smart phone, and were asking about whether you needed to buy a dedicated GPS or could get away with using your phone, I'd answer differently, but if you're after a GPS unit, and don't have the phone already it makes a lot more sense to get the GPS unit, esp if you don't need / want a smart phone.

Cheers,

Stuart

In reply to StuDoig:

That's a really good, helpful, informative answer. We tried using my mate's iPhone for mapping/compass in a whiteout on Monte Rosa this summer when we realised that our compass had reversed its polarity (my fault, put my phone in the same pocket). We got about 5mins out of it, which was just enough to confirm we were heading in the right direction (having used the compass the wrong way round deliberately) , before it died. We resurrected it on return to the hut, but it wasn't happy for quite a while!

Another point is that touch screen smartphones do not seem to work well with gloves on, whereas something like a GPS12 unit can be used with mitts on.

My preference is for go for the simplest gps unit you can - no colour screen, no mapping, just grid refs and using the same batteries as your head torch. Cheaper to buy, better battery life.

In reply to StuDoig:

Plus one to everything you've said fella.
My (very old now) garmin foretrek does everthing the op wants all over the world and shares batteries with my headtorch.
It livesin my pack for the rare occasions I use it and is waterproof enough that I'll use it in any weather. Dirt cheap on ebay now too.
Not sure I'd want the roaming charges using a smart phone overseas either!

In reply to GerM:

Thanks for the replies, all seem to be well reasoned and helpful. Looks like going for the dedicated GPS is the sensible approach. which is good because that is what I'd prefer anyway really. Now to find one to put on the Christmas list then...

I went with a mobile phone upgrade. I have (Viewranger) OS 1:50K for all UK and OS 1:25K for Locahaber, Cairngorms, Moffat/Borders Hills, Galloway Hills & Pentlands installed on a Galaxy S4 'active' (waterproof) with an aftermarket (Otterbox) case for maximum ruggedness. Accuracy is very good, signal fix from 'off' is very quick and it'll easily last 1-2 days with GPS & mobile and the occasional bit of data when in range to look at the rain radar too. I also carry 2 spare charged batteries and had plenty of juice left over after a week's cycle tour without using a USB charger (powered phone off when not required).

It's got a much bigger screen than the cheaper dedicated satellite navigation devices and worked out cheaper than the more expensive ones with similar sized displays. The only downside in the real world is that Android doesn't have up/down/left/right/zoom etc navigation buttons, so rain/snow on the screen sometimes needs wiping off. For peace of mind on a 2 week away from civilisation trip, I would buy another 2-3 batteries @ £4 each from ebay.

In reply to GerM:

I addition to what has already been said, on the reliability and accuracy front:

Most touchscreens on smartphones don't work if they have water droplet on them. The phone can't reliably tell the difference between a finger and a droplet, so as soon as it detects droplets it stops working until it's dried off. So when a phone is sold as waterproof it means it won't be damaged by water, but you won't be able to use it when wet either. Some cases can mitigate the problem, by keeping the water away from the screen, and Sony say their Xperia has "wet finger tracking" and is OK with droplets on it.

The GPS antenna in a dedicated device is usually larger/better, and will keep a lock better in trees, canyons, and bad weather. Metal cases on modern smartphones really aren't doing the user any favors on that front either.

Dedicated GPS systems may have better receivers too. They may get a fix faster if there is no phone signal, as the A-GPS in smartphones download satellite positions (called the almanac) from over 3G if they can, and if they have to fall back to download from satellites it takes ages. Dedicated recievers may be able to download from several sats at a time, so speeding the time to first fix up from 15 minutes to two or three. Good receivers may also be better at recognizing when the signal is being reflected off a cliff face (called multipath) and correcting for it.

In reply to Jack B:


Probably misunderstanding you but if not, I disagree (certainly in Scotland anyway). I frequently leave my phone in 'flight mode' and when I switch just the GPS receiver on, it takes about 15-20 seconds to fix position on the OS map in Viewranger, wherever I am.

In reply to moffatross:

OK, so it's actually more complicated than I said. Firstly as GPS is receive-only, it can remain on in flight mode. Most phones (including the S4 I think) leave it on, some (including iPhones) turn it off. But maybe you explicitly turn it off?

Secondly, when the GPS starts up, a variety of different things can happen. To get a fix, the device needs to know where the sats are. The information it needs is known as the "almanac". How it gets that information depends on the device.
1) It may remember from last time it was used. Typically remembered data is good for a day or two, though my some phones forget after as little as an hour.
2) If it's a phone and has a signal, it can download the almanac over 3G. This is A-GPS. Clever phones will download an almanac every time they get a wifi connection, even if GPS isn't in use at the time, so they have one ready when GPS is turned on.
3) Otherwise, it has to download from the satellites. Each sat is is constantly transmitting the almanac, and it repeats every 12m30s. If you listen to one sat, it takes that long to get it, listen to two at once it takes 6m15s and so on. If you miss some because the signal is poor, you have to wait another 12 minutes for it to come round again.

If the receiver has no idea where it is, there is a little extra delay, as it searches for sats. If it knows roughly where it is (where it was last used) it starts its search with the sats that would be visible from there. A-GPS can also help with this stage, by giving the rough location of the cell tower.

If you get a fix in less than 20 seconds, it's doing case 1 or 2 above. It sounds like the S4 does cases 1 and 2 well, and you rarely hit case 3. My motorolla defy on the other hand rarely gets a fix within 10 mins if there is no 3G signal.

In reply to GerM:

Interesting thread.

I did a lot of map and compass work to hone my navigation skills for a winter award. I had both a cheap Garmin GPS (about £30) unit and an iPhone with RouteBuddy mapping software loaded. I chose to take both for redundancy, but found it a helpful comparative exercise.

My reflections were that the GPS unit was certainly accurate, but the process fiddly, putting the OS grid reference to the map with the compass roamer, big gloves and in bad weather.

On the other hand, as I usually had a good idea of my location since I was tracking it with map and compass, the iPhone was a good way to confirm that and act as a confidence booster. It was helpful to be able to see the contours and OS features on both device and map and compare the two: my estimation and that of the phone.

I kept it in Airplane Mode, having started the app at the start of the day. This meant it was usually quick to update its location and then be put back into Airplan Mode and away in the top of the rucksack.

As long as I didn't use it for taking photos, texting etc., the battery life wasn't a problem. However, I wouldn't use it blindly as a primary method of nav in place of map and compass.

In reply to Si Cox:

So you compared a non-mapping, grid-refs-only GPS to a phone with fully-implemented maps and found the phone gave you a quicker visual handle on things?

I am probably influenced in this discussion by my interest in photography which means I always take a good camera on the hills - Canon G11. I take a basic Nokia Payasyougo phone in case of emergency and to let Mrs Ratty know when to put the kettle on. That leaves the GPS so on walks that include new terrain or have poor weather forecasts I carry a very basic Garmin Etrex (With spare AA batteries) set to use OS coords to locate myself if I get 'lost' in poor visibility and can't use my map & eyes to sort it out. This may be old school but it serves me well and some recent walks with a festival where smartphone users were losing power or GPS signal did not persuade me to change. As for posting pictures from the summit - no thanks.

In reply to petestack:

Yes, since my mind was so focussed on the OS context, it was helpful to have a second device that overlaid that information visually.

The problem with the GPS grid reference (for me, at least), was that it broke up the flow of the navigation process. Also, If your map is folded heavily, you don't always have the northings and eastings figures visible, which can slow down relocating on the map.

I found the GPS functions of the phone accurate and rapid enough to back-up my map work.

My only caveat would be not to rely solely on GPS devices and take the time and effort to learn the mountain craft of manual navigation.

In reply to Si Cox:



Think you might be missing my point, which is that I'm not at all surprised when a mapping GPS would have been a fairer comparison for your phone...


Of course!

In reply to GerM:

Anyone considered the Decathlon "mountainproof" phone? http://www.decathlon.co.uk/quechuaphone-50-id_8294081.html

Might it be (some of the) best of both worlds?

A fair bit cheaper than a galaxy s4 (though not in same league re. Computing power)

In reply to keith-ratcliffe:

In reply to Si Cox:


Map and compass works. Map and compass backed up by GPS grid refs works. Map and compass backed up by mapping GPS or phone equivalent works. Mapping GPS or phone equivalent backed up by map and compass works. It's ultimately a question of usage style and priorities. Until just under four years ago, I navigated the hills exclusively by map and (when necessary) compass. Then, after moving from a non-OS-grid-enabled GPS watch (Forerunner 305) to one that could give an OS grid ref (Forerunner 310XT), I added that to my armoury, though generally just eyeballing the grid refs from GPS to map rather than physically measuring them. But the 310XT's still not primarily a navigating device, I like to keep moving (mostly running) in the hills and find like Si that stopping to transfer grid refs to map tends to interrupt my flow when doing so. So, just as I've moved from 1. just compasses, Breton plotters and paper charts for coastal navigation through 2. transferring lat and long from simple GPS to paper chart to 3. GPS chart plotter, I've found myself wanting a mapping GPS for the hill. And have just bought a new eTrex 20 to load up with OS 1:50,000 Scotland for that purpose. But I'll still run with thumb compass and A4 laminated maps to hand. And my phone's a phone and my camera's a camera!

In reply to GerM:

Look for a standalone GPS with buttons for use in all weathers and thick gloves in a blizzard. Most standalone GPS are cheaper than your typical smartphone, pretty bombproof, run on cheap AA batteries for which spares can easily be carried, have lanyards so you can attach to rucksack or round neck etc. smartphones have bigger screens far better for mapping. If I'm out for a short walk in nice weather in a familiar place I'll often just have the mapping on the phone to check every now and again. But up a mountain in deteriorating weather, stand alone, printed la,inmates maps and compass every time.

In reply to GerM:

I have a Casio Commando smart phone. It's durable and water resistant. With a large battery pack, it's got decent battery life.

GPS functions are great. I never even bother to carry my standalone GPS any more. The phone serves the purpose better than the GPS because it has a much nicer screen, and simpler keypad for entering waypoints, etc.

If you have the right phone, a GPS is superfluous.

In reply to Jack B:

Actually, it's the ephemeris data that is really required, and becomes obsolete within about four hours. The almanac constitutes only a small part of the data required for a cold fix...

That pedantry aside, I'd be very surprised if the GNSS chipset in a modern phone doesn't acquire almanac and ephemerides from multiple satellites. Oh, and the time it takes will depend on which satellites you can see, and the relative position of their 12m30 repeat cycle data frames; I don't think it's as simple as 12m30/number of satellites.

The advantage of a phone is that generation upgrade is much faster than for dedicated GPS receivers, so they're much more likely to be using a more recent GNSS chipset, with more parallel channels, and be able to use multiple GNSS signals. My Hudl can certainly track more satellites than my SiRFStar III equipped PDA, and can use GPS and GLONASS satellites. On some recent experiments for work, the Hudl performed better than a uBlox 5 chipset using an external antenna...

I agree that phones may not be so good at saving their current state, so what should be a quick hot or warm start may actually require a cold start. On the other hand, if it does save the data, then AGPS can be used to quickly get a fix at the start; turn phone on, with network access, acquire time of day, rough position, almanac and ephemeris via AGPS, then turn phone off and use GNSS receive data only.

In reply to captain paranoia:

I pick up GLONASS sats on my phone (Nexus 5), no such luck with my Garmin Foretrex 401.

The phone sure is handy at times, google earth, google maps with sat imagery and the new topo map style[1], and a bright HD screen.

I take both. One generally has ones phone about for non-navigational reasons. Dedicated GPS wins for battery life (replaceable, and more reliable - phone apps can often drain power unexpectedly), durability, waterproofness, simpleness and use with gloves on.


Keep in mind with smart phones and small GPS units, we're often talking digital compass + barameter/altimeter + gps unit, which are all useful navigational aids.



[1] http://pocketnow.com/2014/05/29/google-maps-terrain-view

In reply to captain paranoia:

Loving the geeky direction this seems to be taking.

In reply to GerM:

Being a cheapskate but also having a phone that was dieing, I have just bought a ZTE Kis 3 Android 4.4.2 smartphone for £40 which isn't actually terrible (despite being £40)...

Further purchases:
1:50k OS maps for Viewranger for all the national parks in south Wales and southern England - £2.99
Allegedly IPX8 (fully submersible) phone pouch off Ebay (touch screen compatible) - £2.49 (yet to arrive and I may decide not to trust the waterproofness but should keep the rain off)
2 x spare batteries for the phone - £2.50 each

Hopefully good value given that I got a phone as well I have yet to try it though!

PS the camera is terrible but then you can't buy a decent camera for £40 so it is not surprising!