Satellites not found in Skydemon, reboot the PilotAwareAndroid

[neilmurg]

Has anyone else had this? With a system using a Nexus7 2013 and PilotAwareAndroid to provide GPS data.
s/w release 20151114
Connected to wifi 192.168.1.1
Select 'Go Flying' in Skydemon, Skydemon message 'Seeking GPS Satellites' which it never finds. I was outside at the time. Nexus reported satellite fixes and a position.
Force closed PilotAwareAndroid and restarted it, then satellites are found and it's away.

I tried to reproduce it by starting up inside (shielded from satellites) and going outside and it sprang into life by itself. But it wouldn't show traffic in SD until I stopped navigating then pressed 'Go Flying'

I'll try and get a definitive order of apps starting etc.

[Admin]

Skydemon simply puts up a generic message regarding 'Seeking GPS Satellites', because it has not been given any valid $GPxxx messages from PilotAware.

This means PilotAware does not have a good GPS source provided to it, in this case using PilotAwareAndroid

I guess the first question is, how does the Nexus7 get its GPS fix ?
Is it really using Satellites, or using a combination of Satellites and WiFi (as per iOS location services)

I think shielding the satellites is irrelevent if Android uses a combination of Wifi/GPS to get its location

[ianfallon]

I have the Asus Memopad 173X which is basically a Nexus 7" Android tablet.
It is VERY slow at getting a proper GPS lock.

I'd recommend downloading the free "GPS Test" app from the PlayStore - this clearly shows when the tablet has a proper lock and how many satellites etc.

[neilmurg]

Yes it is slow/prone to drop satellites (in the house, never a problem in the aircraft), I've always assumed small internal aerial due to form factor.
It's not a huge problem, I thought I'd picked up an issue to do with the sequence of apps starting/ satellites coming on line/ wifi connecting and the displaying targets. Possibly where a periodic recheck/reset would help.

As I say, I'll map out a set of start up sequences and come back if I find something. Thanks! :-)

[neilmurg]

I've just been testing 2 units with GPS provided by android phones.
When AndroidPilotAware starts and connects to the PAW wifi with no GPS fix, it doesn't acquire a fix, even when the android device subsequently finds a fix (or it doesn't tell SD a fix is acquired).
AndroidPilotAware has to be killed and restarted with a valid satellite fix, then all is fine.

Happy to run further tests as requested, I know this is not a big problem, most people will have a GPS.

Also, my 2 PAWs incl. ARF detect and warn of each other , maximum tested range: 1.5 metres. Testing farther tomorrow.

[Paul_Sengupta]

Yes, I've found the same thing with mine. Sometimes you just have to kill the app and restart it all again in a particular order.

Since getting the USB GPS though, I'm not so bothered. 

[chrismills]

PilotAwareAndroid doesn't use WiFi for its location fix, only GPS.
However, I'm not sure what SkyDemon does.

Essentially, the Android OS provides an API (programming interface) called "Location Services" which programmers can use for, you guessed it, location data. The API uses the best available source to determine location, GPS or WiFi or 3G. This is an easy interface for coders to work with but it is designed for more usual mobile phone applications. By ignoring the API and working a little more "under the hood", location can be determined from the GPS module only. This is what I did for the PilotAwareAndroid app.
There are some limitations, for example, the Android device must have a GPS chip, and it may take some time to get a fix when first activated.

It is a useful exercise to download and run the "GPS Test" app on your Android device. This will confirm that you have a functioning GPS chip (not all Android devices do) and also that you have a valid fix. Waiting for the PilotAwareAndroid app to populate will do the same.

[neilmurg]

thanks Chris. I have a working GPS chip.
I thought my issue was that if I start the 'Go Flying' on Skydemon while the AndroidPilotAware app is running but before the tablet has a fix, once the tablet gets a fix, Skydemon doesn't recognise that.
If I then kill AndroidPilotAware and restart it (while SD still running), SD then gets a fix.

I could ask Tim at Skydemon...

[chrismills]

OK, so I think there maybe some mis-understanding in how the system is working.

If you select "Go Flying->Use FLARM" then SkyDemon doesn't use the tablet GPS for location services. GPS fix is provided to SD by your FLARM unit (or PilotAware box which is supplying the same data).

I can't exactly explain what else is going on here. When you say "while SD still running" do you mean still in "Go Flying->FLARM" mode?

I would suggest that everything should work OK if you connect up in the correct order. Take a look at "Android" thread for detailed instructions.

Good Luck, Chris

[thearb]

OK, so I think there maybe some mis-understanding in how the system is working.

If you select "Go Flying->Use FLARM" then SkyDemon doesn't use the tablet GPS for location services. GPS fix is provided to SD by your FLARM unit (or PilotAware box which is supplying the same data........

......which may be from the tablet GPS via the collision aware app, depending on setup, just to clarify what Chris is saying.

[neilmurg]

Take a look at "Android" thread for detailed instructions.
Good Luck, Chris

Yes, comment #45, page 4 of the "Android" thread. That sequence always works for me. The only problem I get is when I am using the tablet GPS and I start Skydemon BEFORE the tablet has a GPS location. I'm just surprised that SD doesn't recheck for GPS lock when it's in "Seeking GPS Satellites" mode.

[neilmurg]

the 3 questions this raises with me are:

1) with the PilotAwareAndroid app using the tablet or 3rd party GPS for a fix, if GPS fix is lost while connected to Skydemon (SD), when GPS fix is reacquired does SD resume?
[edit]PilotAwareAndroid doesn't drop it's 'GPS fix', even when the tablet GPS does, I assume it just keeps the last location. That surprised me.[/edit]

2) with an attached GPS dongle, if GPS fix is lost while connected to SD, when GPS fix is reacquired does SD resume?
[edit]yes it does resume[/edit]

3) do any of the nav apps display targets when they don't know where they are (they know where targets are [ADS-B signal is stronger than GPS])?