PilotAware
British Forum => Technical Support => Topic started by: captchaos on May 10, 2017, 12:47:08 pm
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I am not sure if anyone else has experienced this. I am running the latest PAW and SAD on an Ipad mini 4. After a random time SD reports is has lost connection and hence position. Initially I thought this was a power issue as I was using the recommended cig socket charger and wondered if it worked loose. However I had the same with a suitable power bank.
SD worked find with no problems when using Location Services. The PAW appears to keep working fine based upon audio alerts. I am wondering if it is something to do with the Wifi conection?
Any thoughts,clues, etc very welcome.
PS Well done to the team on the OGN tie up. Saw some of this as I headed north at the weekend.
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When the disconnect occurs, is your iPad still connected to PilotAware Hotspot ?
(are there other WiFi Hotspots in range that it tries to connect ?)
When reconnected to the PilotAware WiFi hotspot, can you go to the Web Home page and look at the uptime field in the table. This will tell you if PilotAware performed a reboot (usually due to power)
By recommended power, I presume you mean you are using Anker supplies ?
Location Services is unrelated to the issue you are describing, as Location Services are internal to the iPad
Thx
Lee
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Unfortunately as I was flying solo I couldn't check if the hot spot was still available. There was not other Wifi hotspot. When it happens again I will check those two points you suggested checking.
Yes I am using the Anker power products.
I only mentioned using Location services as I used that to get reliable nav.
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I too have the same problem. I run PAW with SD, with Anker power bank.
I run also an iPhone with Radar screen. When SD loose connection, the iPhone continue to run properly. Next flight I'll check if when SD loose the PAW connection, the wi-fi hotspot is on.
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Capt C, I have had the identical issue many times. Works ok then drops it's connection/ loses position randomly. To the extent that lately if I'm on a trip where I want to use SD properly I just use the iPad's internal GPS (location services) and don't bother with the PaW because it's not reliable enough.
Incidentally I did notice once that following a disconnection, the PaW hotspot was not showing on the iPad's wifi page - and the only way to get the hotspot back visible was to reboot the PaW.
My power is a Charge2.
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Capt C, I have had the identical issue many times. Works ok then drops it's connection/ loses position randomly. To the extent that lately if I'm on a trip where I want to use SD properly I just use the iPad's internal GPS (location services) and don't bother with the PaW because it's not reliable enough.
Incidentally I did notice once that following a disconnection, the PaW hotspot was not showing on the iPad's wifi page - and the only way to get the hotspot back visible was to reboot the PaW.
My power is a Charge2.
Hi JonBoy
This is just not right at all, and should not behave in this manner.
If the hotspot disappears completely this sounds like a wifi dongle issue.
We have seen a small number of WiFi dongles, which for some reason (manufacturing bug)
draw a huge current when put into Access Point mode, this can 'brown out' the power causing the
WiFi dongle hardware to get into a lockup state. I wonder if this is what we are seeing here.
Is this a PilotAware Classic or a home build ?
Which Software version of PilotAware is this running ?
Thx
Lee
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Hi jonBoy,
Just looked up your email and this is a PilotAware Classic.
I would like to try swapping the WiFi dongle to see if this is indeed a culprit, I will ask Dave Styles to contact you
Thx
Lee
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I did some test to try to understand at what level the problem is (IPAs, SD e Classic).
When SD loose GPS signal the hotspot is on, so it seems no Wi-Fi dongle problem.
If I try to reconnect SD, some times it reconnect at the first temptative, others I have to try several times. So it's seems a GPS dongle trouble.
Ha e you any suggestions on how to solve the problems? It's boring to loose the GPS signal while flying
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I did some test to try to understand at what level the problem is (IPAs, SD e Classic).
When SD loose GPS signal the hotspot is on, so it seems no Wi-Fi dongle problem.
If I try to reconnect SD, some times it reconnect at the first temptative, others I have to try several times. So it's seems a GPS dongle trouble.
Ha e you any suggestions on how to solve the problems? It's boring to loose the GPS signal while flying
There are 2 messages produced by SkyDemon
1. lost connection to GPS
This is a WiFi connectivity / TCP Socket issue, and not an issue with the GPS device itself
2. searching for satellites
This is a GPS issue, because the GPS has not achieved a lock
an easy test, unplug the GPS from PilotAware and you will get message (2)
If your iPad is in range of 'known networks' it will drop and reconnect depending upon the strongest signal.
So if you are near your home wifi, you may se the ipad drop the connection to PilotAware, connect to Home, then reconnect to PilotAware
The only way to get around this, is to tell iPad to forget your home network, this will stop t connecting to other networks
I think the best solution between PilotAware and SD, is to use UDP rather than TCP, this is more tolerent to an individual lost packet.
TCP (in the SD implementation) just gives up and stops working.
I have been speaking to Tim at SkyDemon, and he is going to investigate using a UDP connection as a replacement to TCP
Thx
Lee
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I think the best solution between PilotAware and SD, is to use UDP rather than TCP, this is more tolerent to an individual lost packet.
TCP (in the SD implementation) just gives up and stops working.
I have been speaking to Tim at SkyDemon, and he is going to investigate using a UDP connection as a replacement to TCP
Thx
Lee
I'd prefer TCP over UDP.
With UDP PAW just blindly transmits to an address and port, with no idea if they are received or not. At least with TCP the network layer will know that data has gone missing and can re-transmit. With UDP there is no assurance, its fire and forget.
If a UDP packet is lost the network layer won't know, unless the receiver can tell the sender that something expected didn't arrive.
If a TCP packet doesn't arrive or is corrupt, the sender won't get the ACK back, so know it didn't arrive and can re-transmit.
This is all, normally, handled within the network stack, so it should be possible for PAW to display the network stats to see if there are large numbers of re-transmissions going on (i.e. SD is not sending ACKs). Naturally a large number of failures may close a connection, but to KNOW that is a good thing and easy to trap and report.
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Hi Jeremy
No disagreement with what you are saying.
Althought it seems the consensus are all moving to UDP.
The Uavionix devices all use GDL90 over UDP, although I think this is because they use the espressif esp8266 devices, and the TCPIP stack on those devices is notoriously bad - hence UDP by necessity I think.
What I would probably have preferred is that when SkyDemon loses its TCP connection, it simply attempts a reconnection, but at the moment it requires a user intervention, which is painful to say the least when busy flying a plane.
I notice the XCsoar devices all perform a reconnect over TCP if the connection is lost, and I am pretty sure RunwayHD and EasyVFR do that as well.
I will not be taking away the TCP option, basically I will be adding a UDP broadcast to any listening servers on the subnet.
So you can choose your connection
2000/TCP server running on PilotAware
2000/UDP client broadcasting to listening servers on the subnet
Thx
Lee
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TCP re-connect is ideal, and throw an error if this happens x times, although that can hide problems leading to missed data (and potentially alerts)
Although if you are doing a UDP subnet broadcast can I ask you include a heartbeat packet people can listen out for? With that, and they have to add the code to use the UDP anyway, it can be used to alert if a number of heartbeats are missed and so identify there is a problem, rather then deduce it from a lack of anything else.
Essentially listen for heartbeat, so know it's running and it's from a PAW, so start to process the data.
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Hi Jeremy
Does a heartbeat contain any special data ?
The reason I ask, is that a traffic packet goes once a second periodically, so if something hasn't been received for lets say 2 seconds - there is an issue, and if the server has implemented a timeout - this is easy to detect.
Thx
Lee
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Does it send empty traffic data, i.e. if the ADSB isn't connected and nothing is received?
A heartbeat can contain what ever you want, but I think it would be good to send. It splits not receiving any data from the device not being on/reachable. So if the device stops sending the heartbeat something serious is going on, but a lack of any other data could mean there is nothing to send or the system is still working on it.
Naturally the heartbeat could also contain an ID to say it's a PAW, just publish the packet details. The minimum Ethernet packet length is 64 bytes, so plenty of room after the basic header data to include a Hello World ID for the end device to identify who it is listening to, or even determine if several different things are transmitting by associating the ID with the sender IP address.
It doesn't really matter if the receivers don't use it, but no reason for you not to transmit it, to identify a PAW UDP broadcast transmission to anyone listening in on the network segment. If they do decide to use it, they can identify who is sending the broadcast and so what services to expect and what to flag up to the end user if it's missing after a while.
Naturally if it was in a NEMA style format it would be easy to parse for at the remote end.
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I think it might be part of of the NMEA 4.10 anyway...
This sentence is intended to be used to indicate that equipment is operating normally, or for supervision of a
connection between two units.
$--HBT,x.x,a,x*hh<CR><LF>
Field 1 HBT
Field 2 x.x = repeat interval
Field 3 a = equipment status
Field 4 x Sequential sequence identifier
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Does it send empty traffic data, i.e. if the ADSB isn't connected and nothing is received?
Even when there is no traffic it still sends GPS/NMEA, and if the GPS is invalid, ie no lock/satellites visible
it sends NMEA messages indicating that the GPS data is invalid
So there is ALWAYS something sent once a second.
Thx
Lee
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Assuming the GPS source is from PAW too so not ignored by the device as it has a source elsewhere...
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Assuming the GPS source is from PAW too so not ignored by the device as it has a source elsewhere...
Thats fine, because the udp server still has to recv() in order to parse the message in order to discard
Thx
Lee
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I did some test to try to understand at what level the problem is (IPAs, SD e Classic).
When SD loose GPS signal the hotspot is on, so it seems no Wi-Fi dongle problem.
If I try to reconnect SD, some times it reconnect at the first temptative, others I have to try several times. So it's seems a GPS dongle trouble.
Ha e you any suggestions on how to solve the problems? It's boring to loose the GPS signal while flying
There are 2 messages produced by SkyDemon
1. lost connection to GPS
This is a WiFi connectivity / TCP Socket issue, and not an issue with the GPS device itself
2. searching for satellites
This is a GPS issue, because the GPS has not achieved a lock
an easy test, unplug the GPS from PilotAware and you will get message (2)
If your iPad is in range of 'known networks' it will drop and reconnect depending upon the strongest signal.
So if you are near your home wifi, you may se the ipad drop the connection to PilotAware, connect to Home, then reconnect to PilotAware
The only way to get around this, is to tell iPad to forget your home network, this will stop t connecting to other networks
I think the best solution between PilotAware and SD, is to use UDP rather than TCP, this is more tolerent to an individual lost packet.
TCP (in the SD implementation) just gives up and stops working.
I have been speaking to Tim at SkyDemon, and he is going to investigate using a UDP connection as a replacement to TCP
Thx
Lee
I receive the first kind of message. When I receive it, the Wi-Fi icon on IPad is on, full range.
I don't have in my plane any other Wi-Fi hotspot.
If I understand well, the only hope I have is to wait for SD will implement UDP instead of TCP (or TCP with re-connect option).
Thx
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My iPad/PAW combo has had very few connectivity issues, but the PAW hotspot is unique, in that when connected to it none of my iPads have ever shown a wifi icon top left.
Is this normal, and is the fact that MaxMangia is seeing an icon related to the problem?
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Max
How often are you having this disconnect?
Also can you try an experiment, there is a free app called 'telnet lite' for ipad/iphone.
Could you install this and setup a connection for :-
Ip address 192.168.1.1
Port number 2000
When connected to the pilotaware wifi, run the connection defined above.
You will be prompted for a password, you can supply any 4 characters
The gps and traffic information is now streamed.
If we see a disconnect, then we know the issue is connectivity and unrelated to skydemon
I am confident that the issue is unrelated to skydemon, but would like this confirmed
Thx
Lee
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Max
How often are you having this disconnect?
Also can you try an experiment, there is a free app called 'telnet lite' for ipad/iphone.
Could you install this and setup a connection for :-
Ip address 192.168.1.1
Port number 2000
When connected to the pilotaware wifi, run the connection defined above.
You will be prompted for a password, you can supply any 4 characters
The gps and traffic information is now streamed.
If we see a disconnect, then we know the issue is connectivity and unrelated to skydemon
I am confident that the issue is unrelated to skydemon, but would like this confirmed
Thx
Lee
Hi Lee,
The problem is random; sometime in 20' flight it happens 2-3 times, other in 2 hour flight nothing happens. I'll install the software and try tomorrow, I'll fly for 6-7 hours.
Many thanks for your support
P.S. If I connect SD to PAW using Wi-FI and FLARM protocol, I loose any internet data connection (before PAW I paired my IPad with my IPhone). Is there any way to have both?
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Lee
I've just tried my Ipad with PAW and as Graham has said in his last post the wifi indicator on the Ipad disappears when on PAW wifi so I suspect that this is indicative that the wifi has no internet connection.
I started this post prior to Max's last post and was prompted to read it before posting and I think he has answered his own problem. If as he says, the wifi indicator is on when he looses SD connection then is it possible that the Ipad is still trying to make an internet connection via his phone if it is in range. Prior to reading his post I was going to ask if it was a 3/4g ipad and it was trying to establish internet connection that way
Edit: Ipad also throws up a security recommendation when connected to PAW. That could be normal as I very seldom use this combo. I have Android devises for flying.
Alan
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Edit: Ipad also throws up a security recommendation when connected to PAW. That could be normal as I very seldom use this combo. I have Android devises for flying.
Alan
IIRC That's normal if you have no password set on the Wifi.
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Hi Max
Alan raises a good point
Do you have your iphone set to share its internet connection?
If so your ipad could be switching connections between Pilotaware and your iphone
If you want to share your internet connection from iphone, you can do this over Bluetooth instead of wifi
Thx
Lee
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I have a very straightforward setup. Lenovo Tab 3 8inch Android tablet running SkyDemon connected to PAW. Every time I fly at some point I will look down at my tablet to find the 'lost connection to GPS' message. This happens apparently completely at random, sometimes with tens of minutes between problems, sometimes within just a minute or so. Each time I see this message I just tap 'Go Flying' on SD and 'use FLARM' and almost immediately I am connected and back running OK. So PAW is not rebooting etc as it is too quick to reconnect for that and it never has to report 'searching for satellites' either. It appears just to be a simple loss of connection between SD and PAW. However it is very frustrating and I am therefore using PAW less and less and also reluctant to recommend to any fellow pilots. This is such a shame as I would like to have a stable and reliable setup for PAW and SD. Please advise.
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Hi Max
Alan raises a good point
Do you have your iphone set to share its internet connection?
If so your ipad could be switching connections between Pilotaware and your iphone
If you want to share your internet connection from iphone, you can do this over Bluetooth instead of wifi
Thx
Lee
Hi Lee, my configuration is:
IPad, no SIM card, connected via WI-FI to PAW
IPad connect via Bluetooth to iPhone with SIM card and internet connection
However I have tested iPad connected via WI-FI to PAW with no other connection. The problem occurs random in both cases.
To give you more information I have also tested iPhone connected via WI-FI to PAW running radar screen on the browser. In this case I have never lost my PAW connection.
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Sounds like the problem is with the iPad trying to connect to other connections or otherwise losing connection. Can you change your Wifi settings on the PAW, to try various combinations of wireless B or G, with various powers? I had a problem a while back where I used to lose connection if my tablet was too close to my PAW. With one lot of experimental settings it would only work when the two were nearly 2 metres apart or further.
Rogerthedodger, can you try various Wifi settings as well?
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Sounds like the problem is with the iPad trying to connect to other connections or otherwise losing connection. Can you change your Wifi settings on the PAW, to try various combinations of wireless B or G, with various powers? I had a problem a while back where I used to lose connection if my tablet was too close to my PAW. With one lot of experimental settings it would only work when the two were nearly 2 metres apart or further.
Rogerthedodger, can you try various Wifi settings as well?
I have my PAW fixed behind the mount where is the IPad. Do you think could be this the problem?
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Max
What power setting do you have for the wifi ?
Thx
Lee
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I have my PAW fixed behind the mount where is the IPad. Do you think could be this the problem?
I've found that the minimum distance for mine is about 10-15cm, and that's with the correct Wifi settings. Maybe try separating them.
I first noticed a problem with mine driving around in the car when they were 50-60cm apart. This is now why we have settings for Wifi in the PAW! :D
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Paul - I flew today for 1 hour and lost connection just the once when I was only a few minutes into the flight. So for more that 45 minutes it then remained connected OK. My Android tablet is on my right knee and PAW is up on the coaming - this little video shows quite clearly where I have mounted PAW and you can just see my left knee as well -
https://youtu.be/-q4DMLMBdNY
If you suggest I try different WiFi settings for PAW, please could you suggest what I should try?
(Please note I use the recommended lighter plug and cable for my PAW Classic)
Many thanks. Roger.
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Hi Roger
What android pad is this
Paul didn't you have issues with a nexus at some point?
Also Roger, can you leave this running overnight at home to see if you get the same issue
Assuming you have only seen the issue in the plane ?
Thx
Lee
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I did, yes, with a first gen (2012) Nexus 7, hence my experiments with distance. It all went away after one software update after a few changes in the Wifi configuration. I'm not sure I can recommend what settings to use for the Wifi, only to have a play around. Mine's fine with the default settings now, but they are about 50cm apart. Back in the day, with them 50-60cm apart in the car, I used to have Wifi drop-outs.
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Hi,
An update. Yesterday I had 5 flights for a total of 7 hours flying.
In the first twos I used iPad connected to PAW; I loose the GPS signal one time.
In the last three I used iPhone connected to PAW; I loose the GPS signal two times. In the last one I did two attempts before having SD again running in FLARM mode.
In both cases there were no other Wi-Fi connection.
Unfortunately I did't monitor the GPS connection (I did some mistakes using Telnet Lite or, when the problem occurred, the connection was lost and no tracing was saved).
I am sure it's not a Wi-Fi problem, the connection is always on.
I use the recommended power supply to feed PAW.
I have some other pilots asking for me how PAW works. Honestly I don't know what to say; this problem is really boring, in the past using internal GPS I never had any problems.
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Hi Max,
Apologies for stresssing the question again - its confusing because of how SD reports the issue
you say
I loose the GPS signal ...
I think you mean that SD reports 'connection to the GPS is lost'
which really means a TCP connection error over WiFi
I just want to clarify this, because lost GPS will behave differently by producing a banner in SD saying
'looking for satellites'
I think I need to stress to Tim Dawson that we should implement the UDP Traffic interface ASAP.
Thx
Lee
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I have had similar issues in the past, albeit with an Android tablet not an iPad. Since I reduced the WiFi power to 20mW, the problem seems to have gone away - and I have about a metre between the PAw and the tablet. 100mW is the maximum permitted power for a domestic WiFi router @2.4GHz and should be good enough for a range of more than 50m. Airliners excepted, few aircraft are that large, and having too strong a signal can cause more problems than it solves due to overloading of the receiver.
From a network point of view, if you want a reliable network connection, TCP is much better than UDP, but you do have to re-connect in the event of a loss of signal. Personally I would prefer SkyDemon to implement auto-reconnect rather than drop to using UDP.
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From a network point of view, if you want a reliable network connection, TCP is much better than UDP, but you do have to re-connect in the event of a loss of signal. Personally I would prefer SkyDemon to implement auto-reconnect rather than drop to using UDP.
Thumbs Up
:)
UDP simply masks the problem, it doesn't solve it. If there is a comms failure, SD will simply stop getting packets and throw an error, so the same problem is still lurking aware in there. If it doesn't throw an error, then that is even worse!
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I will speak to Tim, I would suspect if it gets no message for N seconds it should display the 'seeking satellites' message it currently does with GPS quality issues
Thx
Lee
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I have had similar issues in the past, albeit with an Android tablet not an iPad. Since I reduced the WiFi power to 20mW, the problem seems to have gone away - and I have about a metre between the PAw and the tablet. 100mW is the maximum permitted power for a domestic WiFi router @2.4GHz and should be good enough for a range of more than 50m. Airliners excepted, few aircraft are that large, and having too strong a signal can cause more problems than it solves due to overloading of the receiver.
From a network point of view, if you want a reliable network connection, TCP is much better than UDP, but you do have to re-connect in the event of a loss of signal. Personally I would prefer SkyDemon to implement auto-reconnect rather than drop to using UDP.
Hi,
How did you reduced the WI-FI power to 20 mW? I should like to try this option.
Many thanks
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Max
What power setting do you have for the wifi ?
Thx
Lee
Hi Lee
How can I verify the Wi-Fi power setting?
Thx
Max
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It's in the Network menu on the PAW.
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I think the default setting for power is now 10mW, but it can go lower
Thx
Lee
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From a network point of view, if you want a reliable network connection, TCP is much better than UDP, but you do have to re-connect in the event of a loss of signal. Personally I would prefer SkyDemon to implement auto-reconnect rather than drop to using UDP.
Thumbs Up
:)
UDP simply masks the problem, it doesn't solve it. If there is a comms failure, SD will simply stop getting packets and throw an error, so the same problem is still lurking aware in there. If it doesn't throw an error, then that is even worse!
If this is true, then simply changing to UDP sounds a Bad Idea to me !! >:(
We need to sort the problem, not create a new one! I suggest this needs further discussion with Tim D as it is obviously going to be an ongoing issue unless sorted properly. If the issue lies with SD, Tim needs to address it to ensure SD automatically reconnects. Manually reconnecting in flight is a real pain and potentially very dangerous.
Regards
Peter
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Out of interest I wonder how much free space is on the sdcard for those who experience dropouts? I think you can check in the track option at the top to see how much free space you have, and delete some old tracks if needed.
A while ago now I had odd issues when the card was full and some housekeeping was run to manage the disk space, its a long shot but might be worth checking. I have a 16Gb card in it at the moment so space isn't an issue.
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Hi,
i drop in just to confirm that also with my IPAD Mini 4 happens the GPS disconnect issue.
Tried dongle change, different power settings, changed wifi name etc. etc. but it still happens, most of the times i get disconnected then no way to reconnect unless some power cycling on PAW hw.
Serial connection to my EKPV continues to work perfect while having the ipad issue.
Federico
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Hi Federico
I think I need to start gathering more detailed information on these issues so please bear with me if I am repeating past questions
1. System
- Is this PilotAware Classic or HomeBuild ?
- if HomeBuild please provide a reference to the WiFi Dongle
2. Which systems DO NOT connect to the PilotAware WiFi ?
- Hardware description
- Software/OS Release
- in all circumstances, on the ground, in the air ?
3. Which systems DO connect to the PilotAware WiFi ?
4. How long does the WiFi connection remain in place ?
5. Power and Power Cable
- please provide references to the power source and power cable
I will continue to add to this list to try and make it more comprehensive
Thx
Lee