Ipad internal GPS reliability [Archive]

peterh337

7th Apr 2012, 21:00

I have found it very unreliable when flying, while others have reported it to be fine.

I have just found an interesting comment here (http://www.sportys.com/PilotShop/product/16597?gclid=CJuXmqDPo68CFQITfAodD3wsYA)

The 3G model of the iPad, in addition to its built-in cellular antenna, also includes an internal GPS. The GPS is completely separate from the 3G data service, so you don’t even have to have an active data plan for the GPS to work. You could buy the 3G model purely for the GPS and never activate the data plan, saving yourself some money. But the on-board iPad GPS was made for ground use, and it’s not very reliable in the air. It has a tendency to drop offline, especially when switching between apps. For this reason, most iPad pilots—even those with a 3G iPad—opt for an external GPS. They are extremely accurate (WAAS-enabled) and very reliable. They also offer free apps that allow you to monitor the GPS’s performance.

which would explain why perhaps some people find theirs OK.

That particular GPS, which seems very hard to buy in the UK (though there are Ebay sellers in the USA charging variously silly postage) also delivers the satellite constellation data, which seems a first for the Iphone/Ipad on which the Apple API blocks that info from apps.

For some reason it cannot be shipped to the UK (http://www.newskyproducts.com/servlet/the-54/Dual-XGPS150-Universal-Bluetooth/Detail) so Ebay seems to be the only option. I guess it doesn't comply with the stupid ROHS/REACH regs here.

Winhern

7th Apr 2012, 22:34

That unit is available in the UK, bought one from Dual Universal Bluetooth GPS Receiver (Wirelessly Add GPS To Your Devices) Deals, #XGPS150A - Expansys.com UK (http://www.expansys.com/dual-universal-bluetooth-gps-receiver-wirelessly-add-gps-to-your-devices-229394/?utm_source=google&utm_medium=shopping&utm_campaign=base&ito=1701) a couple of weeks back. It has performed very well in the one flight I have managed with it so far.

W

md 600 driver

8th Apr 2012, 07:23

I have a iPad1 3G I don't have a subscription ,I just plugged in the 02 sim card supplied when I bought it
I bought a RAM mount off eBay and use it in my heli it's never lost signal yet
I've even used it in a 737 as a passenger at 35,000 ft but you have to hold it next to the window it worked very good

Only drawback i can see is using it in bright sunlight and glare it will need to be placed where you can see it

2high2fastagain

8th Apr 2012, 08:07

Peter, I've been using the Bluetooth gns5870 on my iPad with Skydemon and I'm very happy with it. It seems to pick up the signal quickly and hold it well. I've had no comms issues between the two devices.

peterh337

8th Apr 2012, 08:34

Is the 5870 the one you sweep a finger over the front of to turn it on? A friend has got one and it keeps getting turned on while in his bag.

I still haven't found an Ipad compatible bluetooth GPS which has an external antenna socket and an external power socket. I know one can bodge both of those; the former with a piece of foil stuck to the unit with a cable going to a remote passive antenna (which is how car handsfree kits for smartphones do it) and the latter by wiring up direct to the battery terminals.

It will be interesting if this is also a normal NMEA unit which works with non-Apple products (i.e. with 99% of the GPSs out there ;) ).

dan_vector

8th Apr 2012, 09:04

Peter, I too have the GNS 5870. Yes it is the one that you need to swipe to turn on/off however I haven't had the issue you mention about it turning on in my flight bag. It also comes with a cigarette USB charger which ive used successfully in charging/powering both the 5870 and the iPad or iPhone. Obviously using the appropriate cable.

I've been completely satisfied with it however on comparing specs the XGPS model appears to be 64 channel whereas the 5870 appears to be a 32 channel version. Further looking into the theroy it shouldn't make any difference for our application, having a higher channel sensitivity will probably assist in holding a signal under cover.

I have the standard wifi only IPad 2.

maxred

8th Apr 2012, 09:45

Here is the question, I have been pondering the I pad purchase, but, due to possible mis information regarding the GPS receiver within the pad, I was holding off to look into the IPAD3, with 3g and wifi.

Dan, it looks like the bog standard IPAD2, with wifi only, coupled to an external GPS, will do the trick. Am I correct with this assumption?

Also, do all of the apps available, work on the IPAD2, 16g??

Winhern

8th Apr 2012, 15:19

I have a standard ipad3, wifi only, with the Dual GPS. It runs SkyDemon just fine. :)
Anyone know whats happening with memory map? Their freebie ipad app seems to have vanished from the app store! :{

2high2fastagain

8th Apr 2012, 15:23

On the GNS 5870 - mine does not come on unintentionally at all in my flight bag or anywhere else (including jacket pocket). I think there's a bit of a knack to get the finger swipe right - at least on mine. Battery life seems impressive as well.

To be honest, paying out 70 quid or so for the bluetooth device is a pretty small outlay compared to other frightening avionical adventures I have funded in recent years (including that damned Mode-S transponder that nobody except spotters seem to be able to read). I've put a small velcro circle on the GNS so it can sit firmly on the top of the panel with a nice view of the sky. No problems.

At the risk of tempting thread creep, I have to say that my recent purchases of an iPad, Skydemon, the GNS5870 together with the rather neat iPro aviator kneeboard have massively enhanced the enjoyability of my weekend bimbles.

mutt

8th Apr 2012, 18:26

I use the XGPS150 with an IPAD2 and Jeppesen FD, its a great combination, the GPS quickly picks up the position including in the middle of the Atlantic. Unfortunately for us, the aircraft shielding blocks the internal GPS in the IPAD, some colleagues in a different aircraft have no problem with the internal GPS, but i have never succeeded in getting it to find our position in the air.

Mutt

Humaround

8th Apr 2012, 18:54

I have the GNS5780 and no complaints about its core function, but its ability to turn itself on and drain its battery is becoming a real pain. I went flying on Friday and it had been clipped, face down, against my kneepad in the flightbag.

Even so it had managed to turn itself on. I can always run it off the DC outlet, but it is annoying.

If I was buying another iPad I would deffo go for the 3G/GPS model. My iPhone GPS never seems to fail in the air and most people report the same for the iPad.

peterh337

8th Apr 2012, 19:21

Interesting feedback :ok:

Many thanks for the Bundlebox tip - that is just brilliant. Not expensive either.

Not so long ago I got ripped off $250 for shipping for a tiny jiffy bag from the USA, because the stupid company there (an avionics distributor) would not ship abroad (didn't know how to, apparently) and used an "international shipping company" for all non-US deliveries :ugh: The only issue I see is that some companies won't ship to an address which differs from the credit card billing address, but this clearly isn't common as I have bought many items from the USA directly. It's much more common among UK companies...

When I get the XGPS150 I will report. It should be good because it does EGNOS. Even 32 channels is wasted because there are nowhere near that many sats in the visible sky at any time. What will be interesting is whether it supports more than one bluetooth client concurrently. Most BT GPSs don't.

My current GPS is an old Emtac unit which has a battery but is aircraft powered via a "temporary-attached" 5V power unit, and the antenna comes from a dedicated rooftop active antenna, so it is nice and neat and 100% reliable. But of course it doesn't support any Church of Jobs device...

S-Works

8th Apr 2012, 19:33

Never had problem getting a lock on mine.

Peter, have you ever thought you might be the victim of a conspiracy?

:p:p:p

maxred

8th Apr 2012, 21:29

Thanks guys a lot of good points. Think I know where I am headed re I pad.;)

dan_vector

8th Apr 2012, 21:47

Maxred. Yes an ipad2 coupled with gns 5870 works perfectly with skydemon or air nav pro. I don't believe the ipad3 is worth the extra money unless your into gaming on the iPad. The performance between the 2 is almost identical as the extra graphics power in the iPad 3 is mostly consumed running the retina display. (google it you'll see what I mean!) From what I've seen of others in the flying club many complain about the internal GPS performance and have since bought gns5870's anyway for confidence reasons more than anything.

It makes most sense to me to buy the ipad2 16gb wifi and gns5870 for the same money as a ipad3 16gb wifi!!

Hope that helps!

mutt

9th Apr 2012, 07:12

What will be interesting is whether it supports more than one bluetooth client concurrently It doesn't.... we have tried with two IPADS, it will only connect to one at a time.

Mutt

peterh337

9th Apr 2012, 08:54

That's a pity.

All the GPS repeaters I see are powered, too. That means this GPS would need to be fixed to the top of the dash, which makes wiring up the power neatly a little difficult.

What is the battery life on this GPS?

dan_vector

9th Apr 2012, 09:15

Peter, the gns 5870 advertise 10 hrs battery life. I've flown a 6 hour round trip with it and it was still going strong so I would believe you could get 8-10 hrs on a charge out of it easily.

2high2fastagain

9th Apr 2012, 16:02

Yes, battery life seems OK. I've got 8 hours out of it after forgetting to switch it off when I landed away. Not a surprise that happened. Switching the GNS5870 off isn't yet on my my shutdown checklist and I could smell bacon coming from the clubhouse.

Only complaint I have is that I wish they called it something else. I've already got another GNS in the cockpit.

peterh337

9th Apr 2012, 16:07

I was thinking of the battery life of the XGPS150, not the 5870.

stevelup

9th Apr 2012, 16:57

I've flown six hours with an XGPS150 so far after a single initial overnight charge. The supplied monitoring app tells me I have 22% remaining.

Alan_D

10th Apr 2012, 21:58

I have tried Skydemon on an iPad2 3G, using the internal GPS in a PA28, and it worked fine, had a fix immediately.

Maybe not all iPads are the same, but I don't need an external GPS.

airpolice

10th Apr 2012, 22:36

There is no GPS (as we all know it) in an iPad or iPhone. They call it assisted gps and it is just autotriangulation from cellular network masts.

Get the proper (swipe) bluetooth gps, the GNS 5870 MFI, you'll love it.

I can't imagine going back to "just" the twin dash mounted GNS430s in the PA 28 I fly. Memory Map on the New iPad (it's not called the iPad3) is fantastic.

peterh337

11th Apr 2012, 05:56

An Iphone4 or an Ipad2/3G have a full GPS receiver.

It's not a particularly good one. It's compromised for low power consumption over capture performance. But it is a real GPS.

Piper.Classique

11th Apr 2012, 07:04

There is no GPS (as we all know it) in an iPad or iPhone. They call it assisted gps and it is just autotriangulation from cellular network masts.

Yes there is, if you get an ipad with a sim card. I have a first generation ipad which has a gps and it works well in flight in a cub, running memory map. That is with cellular data turned off, so it certainly isn't using cellphone masts. The gps unit is in the same module as the cellphone unit, is all.

Fuji Abound

11th Apr 2012, 11:56

The new iPad3 is much the same so far as the GPS is concerned as long as you select the with 3G model. I find it is pretty reliable but if I intended to depend on the iPad then I would probably buy one of the dedicated receivers that are available for the iPad.

For avaition use (but I have to say I rarely use mine for that purpose and it was not the reason I use an iPad) it is a reasonable, if not great piece of kit. Personally the dedicated receivers from the likes of Garmins have the edge in my opinion for readability in bright light and reliability but the size of the screen on the iPad is superb feature.

If I wanted a moving map GPS solely for flying I still wouldnt buy an iPad but its a close call.

1800ed

11th Apr 2012, 16:40

So, am I better off buying a WiFi and an external GPS receiver then? I nearly bought a 3G yesterday so that I could use SkyDemon on it on the internal GPS - the amount of people saying how well it worked nearly made me want to eat my own words about iDevice GPS reliability.

AdamFrisch

11th Apr 2012, 17:17

I've used my iPad2 for almost 100hrs and on over 3000nm long cross country trips. I have had one "unable to find fix" in all this time and it lasted for less than 2 minutes. It consistently delivers 10m accuracy, often less than 5m. I did buy a BadElf external GPS that plugs in to the charging socket, but don't use it much as I can't charge through it (the charger provided blew up on 24V, of course).

The iPad2 and Foreflight here in the US has literally changed my life. It's the best thing ever.

riverrock83

11th Apr 2012, 18:18

There is no GPS (as we all know it) in an iPad or iPhone. They call it assisted gps and it is just autotriangulation from cellular network masts.

WRONG
Assisted GPS (A-GPS) means that getting the initial GPS fix is sped up through use of downloaded data, rather than having to get the data directly from the satellites. It is still GPS - using the same satellites to get a position fix as all other GPS devices. Once an initial fix is established, downloaded data is not longer used.
When on the ground, you are likely to notice that getting an initial fix is much faster on devices (phones, etc) using this, especially in built up areas, than traditional GPS devices.

The issue is that some devices appear to rely heavily on A-GPS to get their initial fix. Therefore if you try to start such devices when there is no data network available, they can struggle to ever get a GPS fix (the long lag time may cause something to time out, and so will no longer look for a signal).
If no network data is available, satellite data needs downloaded from the satellites themselves, which requires maintaining a download from a single satellite for about 30-40 seconds. If a device has a poor receiver, or in a poor signal area, an initial fix will never seem to happen.

See Assisted GPS - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Assisted_GPS)

1800ed

11th Apr 2012, 19:45

So the best bet is to get it going on the ground to get a decent position fix and then it ought to be ok?

riverrock83

11th Apr 2012, 20:16

Indeed.
However if you switch apps, and so turn off searching for GPS - you will be back to the start of getting an initial fix again. The GPS receivers on multi-purpose devices aren't as sensitive as the specialist devices so it does depend on which plane you are flying in as to whether you can rely on the internal ones.

peterh337

11th Apr 2012, 21:25

So the best bet is to get it going on the ground to get a decent position fix and then it ought to be ok?

That is true for good many GPSs, actually. However I found the Ipad2/3G losing its fix in the air, having got it prior, and that is weird.

However if you switch apps, and so turn off searching for GPS - you will be back to the start of getting an initial fix again.

That might explain what I was seeing. A crap design though.

peterh337

17th Apr 2012, 14:44

I have just got the Dual GPS.

It works OK, and the free phone shop app shows the satellite details too.

But there is no way, in the Ipad2, to select which GPS to use. I have so far only tried it with Memory Map and it appears that if the external GPS dies, the app just quietly stops working, or quietly switches over to the built-in GPS - with its reliability issues.

I don't know if other GPS apps on IOS have an explicit config for which GPS to use, but I have never seen this. It's really crap.

The only solution is to put the Ipad into Airplane mode, when the internal GPS is disabled.

The other thing I noticed that when the GPS battery goes flat, the MM app just sits there, showing the last position. No message, no warning...

Prop swinger

17th Apr 2012, 15:08

The other thing I noticed that when the GPS battery goes flat, the MM app just sits there, showing the last position. No message, no warning... The centre dot that flashes with each position update stops flashing & the outer circle turns from red to grey. If you use the velocity vector, it will disappear when position updates cease.

stevelup

17th Apr 2012, 16:28

But there is no way, in the Ipad2, to select which GPS to use.

It uses any external device in preference to the internal one.

I have so far only tried it with Memory Map and it appears that if the external GPS dies, the app just quietly stops working, or quietly switches over to the built-in GPS - with its reliability issues.

There is an API provided by Dual which allows an application to see the full satellite constellation, DoP and battery charge level. It may be worth 'feeding back' to Memory Map that this would be a good idea.

The other thing I noticed that when the GPS battery goes flat, the MM app just sits there, showing the last position. No message, no warning...

MM really should alert on loss of GPS reception. It is far too subtle at the moment.

goldeneaglepilot

17th Apr 2012, 16:49

The Ipad2 uses a Broadcom 4751 integrated GPS chip. Which is excellent but limited with its aerial.

A better solution seems to be an external GPS receiver (can be bluetooth or USB), we find the latest Skytraq Venus 6 chipset models hard to beat in terms of speed and the ability to remain locked to sats.

peterh337

17th Apr 2012, 19:41

It uses any external device in preference to the internal one.How "sticky" is that preference? There must also be some sort of hysteresis so it can revert to the external one if that comes back online.

I've found the bluetooth link to be very dependent on the GPS being well charged, versus the distance between the two units. So when the battery runs down (to a point which is dependent on the connection distance) there will be a point in time when the thing basically becomes unusable, but this point can't be determined readily, it appears. Then at some point the Ipad will try using its internal GPS, which I find highly flakey during flight. Whereas with the NMEA serial data used on all other portable devices the app can immediately tell if the data is rubbish - within about a second or two.

The inability to explicitly configure which GPS to use is really stupid.

It may be worth 'feeding back' to Memory Map that this would be a good idea.I have emailed them many times with no response, nor have I ever come across anybody who managed to establish communication with them.

TBH the moment Oziexplorer comes out for IOS, MM will be history. The only reason anybody in GA uses MM is because the CAA charts come in its format, but it doesn't take long for somebody out there to scan them in into a generic graphic file...

I do have the IOS app for the Dual GPS, which shows the sat data. It's slick. Oddly enough it won't compute a fix with less than about 8 "green" satellites though.

S-Works

17th Apr 2012, 19:45

Memory map is crap. Half the problems you are seeing with the GPS are down to it. I switched to ANP and gave never experienced any of the GPS problems you have. It allows use of the CAA charts and s way more useful.

peterh337

17th Apr 2012, 22:11

The ANP (http://www.dixdouze.com/xample/index.php/airnavigation) website doesn't appear to indicate one can load own maps onto it.

Re the bluetooth GPS connection... one thing I see is that if you switch apps on the Ipad, the connection is briefly broken. I don't think Apple meant this as a serious nav device.

riverrock83

17th Apr 2012, 22:15

I suspect Memory Map's issue is that the iOS APIs don't include a way of telling whether a location device is even connected, never mind controlling which device should be used. All they say is "location is X, with an accuracy of y". You then need to work out whether the accuracy is good enough (or the phone is actually using cell tower triangulation)...

Since their App was one of the first (if not thee first) on the market to use a GPS on iOS, it will have been written before the other libraries were available. For them to get more detailed GPS info, they will need to re-write that section of their code, but using other GPS libraries, which is probably not trivial. The libraries are specific to each GPS type, so may not work with future released external devices. From a developer's point of view, that will add an additional cost to manage and support the app.

I doubt its rocket science though - and to me it seems a must have feature!

peterh337

18th Apr 2012, 07:30

S-Works

18th Apr 2012, 07:38

I think the ANP talks directly to the GPS along with being able to share the GPS data by Bluetooth. I can choose between my Bluetooth GPS and internal from within the app.

In answer to your question about maps, no you can't use your own, you buy through the store. Which is simpler for my needs. It does include loads of free maps as well though.

riverrock83

18th Apr 2012, 09:14

Does the app need a "GPS library"? It should merely need to call the IOS API. But maybe for a bluetooth GPS it can communicate with it directly. The Dual GPS app which shows the satellite constellation is obviously not talking to it via the API because that info is blocked by Apple.

On the plus side, the Dual GPS is doing a good battery life - I am at 15hrs now and it is showing 30% left.

As per my previous post, my understanding is if an app uses the iOS API, it has no way of telling which GPS device, if any, is connected. It also has no way of knowing whether the device has a signal (other than by looking at the horizontal accuracy and time of the most recent "fix"). The API could be reporting a cellular triangulation fix, accurate to maybe a mile, it could be reporting using the internal GPS or it could be reporting using an external GPS. It hides all of this from the developer. Its designed for one off location queries from shopping apps - not navigation.
To get more detailed, and controllable information (such as being able to select a GPS device), a developer has to use code libraries from else where or write the code himself to communicate to the GPS (internal or external) devices.

peterh337

18th Apr 2012, 09:31

To get more detailed, and controllable information (such as being able to select a GPS device), a developer has to use code libraries from else where or write the code himself to communicate to the GPS (internal or external) devices.

OK; I see that. But it's not hard because every normal GPS does bluetooth and NMEA is standard. That is how the "GPS world" worked before Jobs did it his own way....... and compatibility was IME excellent across products.

What I don't know is whether it will ever be possible to use any normal bluetooth / NMEA GPS with the Ipad, because under Settings none of them show up at all. Jobs seems to have banned the support of a normal "serial" bluetooth device. But evidently units like the Dual do somehow deliver a full-featured data stream over bluetooth, into which they can stick any data they want, and presumably this could be straight NMEA again (anything else would be totally illogical in marketing terms).

I do hope that Oziexplorer does this correctly and not just uses the stupid IOS GPS API...

Yazdan777

29th Oct 2013, 17:53

With all do respect
My dear feiend i found ipad realy useful and oprational in flight i have checked its accuracy with nav sys of aircraft ( fokker 100) several time and its realy reliable the only thing needs to mention is that avoid using it contineously since desply on cause ipad warm up and heat up which cause to battry loss ...
Using it in short intervall is a good remedy and avoid direct sun light but overally its a problem you have not to deal with in night flight .
Wish you all safe and sound flights .:)