Comments

• Anthony August 9, 2016 at 7:49pm

  Hey guys, unfortunety, CREATE UAS is out of the running. We had a very nasty crash while landing yesterday. Good luck guys! We will be keeping track of the competition.

  Here are some photos of the carcass:
   
• 

  JB August 9, 2016 at 9:14am

  Thanks Tridge for the info.

  I know you have your hands full atm! (we're still pretty busy as well!) But where can I get my hands on the RFD900X? Sounds like it has all the features we need! Any release dates? ;-)

  If you don't mind, we might get back to you on adding it to the old Sik firmware ourselves, if our other options don't make it through range testing.

  BTW we had major quad ESC problems for about 2 months, before we figured out that the Q_RC_SPEED settings would drop frames if they didn't match what the ESC expected (in particular BLHeli/Simonk). We changed it to a multipule (ie 300 for 600Hz ESC) and haven't had any problems with overheating motors and ESCs since. We've also found that yaw control on the quadplane can cause some motors to go to max, and in high wind this can have the effect that it no longer climbs at all, in particular when trying to maintain position. Turning off yaw made it climb much faster of course, but is not ideal for weathervaning.
• Developer

  Andrew Tridgell August 8, 2016 at 2:39pm

  @JB, I have implemented 3 node relaying for the RFD900x but not for the older SiK radios. I would be happy to describe the changes needed to implement it and someone else could add it to the SiK firmware if they want to. It is possible, but the low resources on the SiK radios means it will be a bit tricky.It would require the serial.c packet buffers be greatly reduced in size on the relay aircraft to accommodate a relay buffer.

  I can't promise to add it to SiK myself as I need to prioritise development tasks for CanberraUAV at this late stage. I have a long list of things to get done and not a lot of time!

  tricky.it

  This domain may be for sale!
• Developer

  Andrew Tridgell August 8, 2016 at 2:34pm

  @Nick, that arrangement will work at short range, but won't work as described at long range (yes, we've tried it).

  The problem is that even when the first radio on the relay aircraft is transmitting on a different channel to the channel the 2nd radio is on there is sufficient out of channel power to stop reception at any significant range. So you get a very high level of packet loss.

  You can mitigate this by putting the two radios very close together and using LBT_RSSI to tell both radios not to transmit if they can sense another radio transmitting. For example, set LBT_RSSI to 100 and have the two radios within a few cm of each other. That does work (we've tried it) but you do end up with quite a lot of packet loss.
• 

  JB August 8, 2016 at 7:39am

  Hi Tridge

  Thanks for the info. Does that mean that you are looking at supporting packet relay for multiple aircraft in an upcoming Sik firmware release? ;-) I read in one of your posts from last year that it might work using the Ardupilot forwarding rules using different sysids. Would you be able to elaborate on how to set that up and make it work please, whenever you have the time? Thank you in advance.

  Regards
• 

  Warren Eather August 5, 2016 at 4:35am

  Hi Tridge,
  A year back you might remember I blogged about a proof of concept solution to this issue by using a combination of single & multipoint firmware and 5 Tx/Rx.
  Although we never tested it beyond line of sight it did seem to work remarkably well with minimal packet loss.
  
  http://diydrones.com/m/blogpost?id=705844%3ABlogPost%3A2105658
  
  Waz
• 

  Nick Sargeant August 5, 2016 at 3:49am

  Thanks for the info Tridge. We intend to use 3/4G modems so should (hopefully) be ok. We don't intend to use SiK MP, but for the benefit of others wanting to use a relay aircraft, can you confirm it is possible to do the following using Ardupilot's MAVLink Routing:

  GCS 

  -SiK radio connected to relay aircraft (NetID-A)

  Relay aircraft (SYSID-X)

  Telem1 -SiK radio connected to GCS (NetID-A)

  Telem2 -SiK radio connected to retrieval aircraft (NetID-B)

  Retrieval aircraft (SYSID-Y)

  -Telem1 SiK radio connected to Telem2 of retrieval aircraft (NetID-B)

  In this case, though I have not tested it, would it be possible to run MP SiK on the radio connected to Telem2 on the Relay aircraft, MP SiK on retrieval aircraft and have a second radio running MP SiK on the GCS?

  Good luck everyone!
• Developer

  Andrew Tridgell August 5, 2016 at 3:10am

  One team told me they were planning to use the RFD900 multipoint firmware to do radio relaying for the challenge this year. I just wanted to let everyone know that won't work. The RFDesign multipoint firmware does not do any packet relaying. It is designed for multiple ground stations, not for multiple aircraft. You don't need relaying for multiple ground stations and the firmware doesn't implement relaying.

  If you test it at short range it will appear to work but it will actually be sending packets directly between the GCS and retrieval aircraft. Once they are not in line of sight it will stop working.
• 

  Stephen Dade August 4, 2016 at 4:39am

  We're all good for our D3 hours. Currently sorting out our final comms payload and ground station. 5 mavlink streams per UAV is a good level of redundancy!
• 

  JB August 3, 2016 at 7:42am

  Hey there OBC teams!

  I was just wondering how everyone was going with there D3 and logs. We've been pretty unfortunate with scheduling and weather until now, but we're getting there. Only one more week to go!

  Out of interest I was also wondering who has the lowest current draw/energy consumption platform so far?