In EV3, the waning you get is something to the effect of "No GPS signal, so I've no idea where we are". EV3 requires the pilot to decide which GPS source to use, and to configure EV3 settings accordingly, and if that GPS fails, it's up to you to then delve into the settings and try to get it working with an alternative source (assuming you have one!) or revert to chart, compass and stopwatch. 

EV4 is smarter, You can adjust the settings to force a particular GPS source and interface, or you can set "automatic" and it will choose the best interface to the available external GPS sources, but if the external sources fail to provide a good signal it reverts to the internal GPS.

So, why might you feel you want to know that it has changed source? That might rather depend on why it has had to change, but it has no way of knowing why the preferred source has failed. Perhaps it has some internal fault and you need to get it fixed or dump it and buy a new one. Perhaps you forgot to charge it and its battery has gone flat? If the external source is also your electronic conspicuity source, then you might like to know that that is no longer able to give you the warnings you expect or to transmit your position to others? Perhaps (if it is one attached by a sucker) the sucker has fallen off and the SkyEcho is now on the cockpit floor where you might tread on it? If your external GPS normally has a power feed perhaps the lead has become unplugged? Depending on your set-up, changing source may mean you have a somewhat less accurate output but probably still OK for navigation, but it is possible that you have changed between two sources, one which outputs altitude relative to the GPS ellipsoid, and the other gives altitude relative to mean sea level, so suddenly you might see an altitude offset of about 180ft.

Having such a failure indication should be a pretty rare event and getting a one-off warning is probably not an excessive penalty to know your aeroplane is not working as well as you thought it was? But you seem concerned about  a frequent warning, which of course is much more intrusive and annoying. But if you do get a repeated warning, there really is something fundamentally wrong with your equipment that needs to be properly investigated and fixed, some sort of intermittent fault, dry joint, poor connector, broken wire, poorly-located antenna or whatever. Sounds like you have a bit of engineering investigation to undertake, Alan! Meanwhile, change the setting in EV4 (Menu>System>Location(GPS)Source) to force it to use the internal GPS and you won't be troubled by the warnings (until the internal GPS fails and you have nothing!)

VBR

Stu

Hi Stu,

I have Ev3 and Ev4 running alongside each other in the aircraft. EV3 on Ipadmini2 and Ev4 on Samsung Galaxy S2.

Ev3 runs perfectly. No messages about GPS changed or failures!

My aircraft is only 5years old, built by me, including all avionics and electrical systems. I am confident that I do not have any engineering/electrical faults within the aircraft.

in Ev4 I get this message 'GPS source changed' 3-4 times per flight which requires intervention/acknowledgement. Yes I can change to a single source within Ev4 settings however I strongly suspect I will then get a 'GPS failure' at some point which is obviously undesirable.

My point is that I do not need to see or need have this popup on the screen that is has changed GPS source that then requires acknowledgement. If it has changed source and kept things stable GPS wise then great, but I don't need to repeatedly be told this.

I don't need to see or have this repeated popup that Ev4 is doing what it is supposed to do, that is my point! 

You say Ev4 is smarter than Ev3. From a technophobe's point of view sitting on the ground I would certainly have to agree! From a pilot's perspective however I would say it is currently very cluttered, demands too much attention in flight and is unnecessarily overcomplex with too many options and features!

Regards,

Alan

Did two flights today of 1.25 and 1.15hrs. Galaxy S2 Tablet with EV4  and .897 and I got the dreaded 'GPS source changed' large popup at least 6times on each flight!

I appears to switch between the GPS module on my Dynon Skyviews (x2) and the GPS either in the Tablet or the GPS module in my PowerFlarm Fusion. This message with the for need acknowledgement intervention is very annoying and as I have said before is unneccesary.

I just fail to understand despite Stu's comments why there is a need to have this constant message of it switching GPS!

I am reluctant to change it to a single GPS source in case of total GPS failure.

EV3 on ipad mini2 doesn't do it!

Can this popup message in Ev4 be erased please.

Alan.

Hi Tim,

PowerFlarm Fusion is not losing GPS neither are my Dynon Skyviews!...They both work perfectly!

It is the Tablet running Ev4 that is constantly changing position source. Ev4 is constantly changing GPS source for some reason. But that is not the issue!

The problem is not the fact that the position source is changing but the fact that every time it does change Ev4 shows a large popup that requires acknowledgement and does not disappear until it is acknowledged. It is the popup that is unneccessary and just causes distraction!

Alan

Hi Tim,

I do not have Flarm/Butterfly Air Connect enabled.

It is difficult, because I am now back to regular flying and it has been a while!.. and over the winter I have fitted PowerFlarmFusion to the aircraft.

Last year I was getting the GPS source popups and they did specifically say that it had changed to 'Dynon Skyview GPS position source', presumably because that was the only alterntive GPS it could change to?

Now I have added another GPS module to the aircraft i.e PowerFlarm Fusion I am getting an addditional 'GPS source has changed' and the problem has increased dramatically.

Sometimes it shows it has changed to 'Dynon GPS' as a position source and sometimes it doesn't specify. It just says 'GPS source changed'! so I am assuming, and only assuming, that it has changed to the PowerFlarmFusion GPS module as a position source.

These popups are driving me nuts and somehow I need to eliminate/reduce them!

if they only showed briefly and then disappeared I could live with that, but it is the fact that it requires intervention to press the 'X' to make the popup disappear that is the issue.

Alan.

Sorry Tim I have just realised I hadn't fully answered your question.

I have PowerFlarm Fusion for Traffic hard wired (RS232) to Dynon Skyviews(x2) screens and also (RS232) to Aboba V3+display.

I am also using GDL90 from PowerFlarmFusion for Traffic on EV3 and Ev4.

The Dynon Skyviews have a large GPS module. PowerFlarmFusion also has its own GPS module. The two Tablets being used also obviously have their own internal GPS's.

Hope this helps further.

Alan.

Hi Alan,

EV3 doesn't have an auto-switching GPS source, that is why you don't get the popup there. Exactly the same behavior can be created on EasyVFR4 by not using "automatic" as GPS source, but use either your Dynon or PowerFlarm. Just like EasyVFR3 you can then change manually to a different source if you notice a problem with the one currently selected. Maybe that discomfort is a lot less then having to acknowledge the "GPS source changed" popup for the time beeing? 

With automatic GPS source selection, it is to be questioned *why* this changing is happening. If the changing is from one external unit (Dynon) to another external unit (Flarm Fusion) or visa versa, then the cause is in the tablet switching from one Wifi network to the other. Removing the option "automatically connect to this network" in the tablet's wifi settings could possibly solve this. 

Another problem could be the Flarm Fusion : As you wrote to me by email recently, Flarm has confirmed a bug that the GLD90 output is only available when a sufficient high RS-232 (the other port connected to the Dynon) speed is selected. This makes me wonder whether there maybe is another bug in the Flarm Fusion that occasionally stops GDL90 data feed when the amount of data to send over RS232 becomes too much. Its just wild guessing; I know, but simply removing the requirement to acknowledge the GPS Source changed popup is too short cornered at the moment; that requirement is also put in on specific request by some users, so we have to find a way that makes everybody happy. 

Hi Rob,

Seems I have no option but turn off Auto GPS source switching in Ev4 doesn't it, which seems less than satisfactory but I have no option. The constant GPS source switching popup is too much of a pain to continue with. 

Incidently PowerFlarmFusion now works perfectly fine with a higher GDL90 Baud rate so don't really think that has a bearing on the GPS source switching. I personally think it is the fact that having a total of four different GPS modules from different pieces of equipment in my aircraft and Ev4 perhaps being too sensitive and can't make up its mind which one to use is the issue. The popup needing an intervention before it disappears then compounds the problem.

Alan.

Alan,

It would be useful to watch it carefully and see which sources it's swapping between. It might give a clue to why it's happening. 

Colm

Hi Colm,

This feature is in my opinion unuseable in a modern aircraft with multiple GPS modules and a review is required in the way that it is displayed in Ev4 and the requirement for it to be acknowledged every time it changes GPS source!

It needs to be replaced with a 'GPS source completely Lost' popup and that is all that is needed that reuires acknowledgement.

I have flown today two 45 minute flights and seeing your message last evening I left it is 'Auto' mode during the flights in order to be able to answer your question fully.

It repeatedly changes between 'Integral GPS' and 'Dynon Skyview GPS' and what it call 'Stratux/Flarm GPS' which is the GPS module on my PowerFlarm Fusion. It just goes around and around the different GPS modules and each time it changes GPS source it requires acknowledgement!

As aircraft are fitted with more and more modern technology and multiple GPS modules having this 'Auto'feature in EV4 is unworkable in my view.

As previously stated from now on I have no option but change it to a single GPS source only.

Alan.

Different people will see it in different ways. 

In my case for example, I have my tablet connected to my PilotAware. It gives a better gps reception due to its location. But I leave EV connected to "Auto" so that if that fails, it automatically falls back to the internal GPS. 

I *would* like to know if the signal is lost from my PilotAware, because it means something has gone wrong and I want to fix that before I lose the GPS on my tablet too. My tablet sits on my lap and means it's much more shielded to the outside world, so signal loss on it is quite likely. It's rare that i get a message that the signal is lost. Maybe once in 5 flight, if even that. And when I do, it's probably as a result of something like a steep turn which shields the signal. 

I hope that helps you understand why some of us would like to know why the signal is lost on one device. 

Now looking at your specific situation, it appear that you are getting your GPS signal from 3 different sources. 

1. Dynon SkyView

2. PowerFlarm

3. Internal GPS. 

If I'm not mistaken the first two are on wifi connections.

So what appears to be happening is that your tablet is connecting to one device (let's say the SkyView) and then it disconnects from the Wifi for some reason.

You now get a notice that it's changed to the internal source. 

Then your tablet finds the wifi for the PowerFlarm and connects to that. 

You now get a notice that it's connected tot he PowerFlarm source.

Then your tablet disconnects from the PowerFlarm wifi. 

You now get a notice that it's changed the source to the internal GPS.

Then your tablet finds the SkyView's wifi again, and connects to that. 

You now get a notice that the source has changed to the SkyView.

So the question arises as to why your tablet is constantly swapping wifi connections? If you think you're connected to your PowerFlarm for traffic, when you're mistaking for a lot of the time, because a lot of the time you're connected to the SkyView with no input from the PowerFlarm. 

This is a problem because you can only be connected to now wifi network at a time, and you'll need to choose which one it is. EV reporting the changing in connection is the symptom rather than the problem. The problem is that your device is constantly swapping wifi connections. 

You'll need to decide whether you want to be connected to the PowerFlarm for traffic info or SkyView for flight plan transfer, and then connect to that network and ask your tablet not to swap connections (that might have to be telling it to "forget" the other network if there is no other option to force it to keep its connection). Then you'll know which service you are connected to, and those messages will go away, unless it loses the connection for some reason, and you'll probably want to know then why it's gone!

I hope that helps you to understand what's going on. You likely think you have functionality with your PowerFlarm or your SkyView which you don't actually have at that moment! Ev has just brought that loss of functionality to your attention. 

Hi Colm,

I understand exactly what is happening. However it is the constant and repeated, 7 times I counted in a 45minutes flight today, and having to acknowledge that it is changing GPS source that is very distracting and quite frankly infuriating!

We only need to know and need to acknowlege when GPS is 'completely lost' is my point.

Alan