Activity update: Bushfire response
It’s time that we give you an update on what we have been up to! Our team was set up in 2011 to bring like-minded individuals together to help drive the development of open-source UAV technology to deal with real-world challenges, li ke those that we deal with in the UAV Challenge.
Thanks to the craziness of 2020 the UAV Challenge organisers have postponed the competition until next year. Keen to turn this disappointment into an opportunity, our team has pivoted into another project that can use open-source UAV technology for good. We are really excited to tell you that we have been working with a great team at the Australian National University to help them to develop a ‘water glider’ that can provide a rapid response to bushfire ignition.
To quote our friends at ANU,
“A prototype water glider is under development in collaboration with Canberra UAV. It involves an innovative technique for water bombing from high altitudes (well above 5000 feet) which significantly mitigates the risks inherent in current approaches, providing very rapid response while obtaining high accuracy and good control over the spread of the water. It also allows the use of unmodified aircraft thus increasing the number of available aircraft and lowering costs. Proof of concept demonstration will be achieved in the short term.”
You can read all about the ANU project here:
We are still working on some development towards the 2021 UAV Challenge, which we will provide an update on in a future post.
We hope our friends and Patreons are keeping safe and encourage you to support our sponsors Airborne Innovation, Microhard, HolyBro and HobbyKing to supply the kit for those lockdown projects!
UAV Challenge 2020 communications update
During the 2020 challenge we will need to control our ‘rescue’ quadcopter in a farm shed up to 12 km from our ground station and establish a video and audio link to the farmer in the shed, without any dependence on the cell phone network. Quite a challenge! We think that this really pushes the limits of technology that is available to the hobbyist, community groups and small businesses.
Our general philosophy for the 2020 UAV Challenge is that we want to have redundancy in our networks to avoid a single point of failure during the mission and to take advantage of the opportunities of radio frequency diversity. By having two networks operating on different frequencies we should maximise the data rates available at higher frequencies (such as 2.4GHz) while exploiting the reliable range performance and better object penetration of lower frequencies (915MHz).
We have had some significant testing success with our communications for the 2020 UAV Challenge in the last few weeks, including a strong connection at 11.2km for all three of the radio types that we have tested: our Airborne Innovations and Microhard 2.4GHz network, our trusty RFD900Xs and some promising open source ‘New Packet Radios’.
Airborne Innovations and Microhard have generously supplied us with set of 2.4GHz pMDDL2450 based radios to potentially use in the competition. We recently tested this in a point-point link test at 11.2km. The representative air platform was on top of a hill connected to a Holybro Durandal to establish a representative MAVlink connection to a ground station. On the ground we used a video aerial systems super cannon and pepperbox antenna while the ‘air platform’ used MadMusroom antennae. We established a good telemetry and control link with very low packet loss and a fade margin of 12dB, which we are pretty happy with. These radios can be set up to mesh network, so they could be used like the RFD900x to link the rescue aircraft to the ground station via the communications relay aircraft. This set up has potential for telemetry, control, video and audio from the rescue aircraft, but we have more testing to do here.
The RFD900X radios are very capable and reliable for maintaining long range line of sight control and telemetry links with the UAV; their ability to mesh network also makes them very useful to use with a communications relay aircraft when we lose line of sight with the rescue aircraft. We used these successfully in 2016 and 2018. The big change for the 2020 challenge is the need to send video and audio from the rescue aircraft back to the ground station. We have been working on a new video encoder that can send video at very low frame rate over a low bandwidth over the RFD900X alongside the control and telemetry data. We are having some success here and it looks promising, so we have more testing to do with this setup.
The New Packet Radios are an open source design that uses the same STM32 radio module as the RFD900X but operates at around 433MHz. We think it would need a Ham (amateur radio) to operate it at the necessary power for the challenge. These radios showed good potential for a link with a good data rate between the ground station and the relay aircraft. Unfortunately these radios lack the small form factor to fit onto the rescue Quadcopter so it would only be useful for connecting the ground control station to the comms relay aircraft. For this reason, we have decided not to proceed further with testing these radios as part of our 2020 Challenge project.
Holybro Durandal auto mission testing
Jimmy has been learning how to run auto missions with a Hobbyking Bixler 2 and a beta test Durandal unit.
Here’s how it went:
https://discuss.ardupilot.org/t/holybro-durandal-user-experience-in-bixler-2/49122
Communication testing
Full disclosure; our current communications testing for the 2020 Medical Rescue UAV Challenge isn’t the richest material for a visual update!
We think that communications is the biggest challenge for the 2020 mission. We will need to maintain video, command and telemetry links with a QuadCopter in a farm shed 12km from our ground station. We will need to use a communications relay aircraft near the shed so that we can maintain radio ‘line of sight’ links throughout the mission. Its no small challenge to do this with lightweight accessible hardware! We are working hard on testing a number of communications options including 433MHz, 900MHz and 2.4GHz options.
We tested our current systems at 11.2km between a local hill and our flying site. With basic omni-directional antenna the RFD900Xs easily achieved and maintained a link with a 125kb air data rate. You can see below that this was a good enough to issue commands to one of our HolyBro Quads.
We have plenty of experiments left to do; we need to get some of the patch antennas set up so that we can do some experiments with our Airborne Innovations and MicroHard radios to see what performance we get from them at similar ranges.
Finally, we have another exciting option that we are working on. Carlos has been looking into some open source 433MHz digital IP based radios. These radios are called NPR (New Packet Radio). They are a custom radio protocol, designed to transport bidirectional IP traffic over 430MHz radio links (ham radio). This protocol is optimized for “point to multipoint” topology, with the help of managed-TDMA. Bitrate is advertised as up to 500kbps (net, effective bitrate). We’ll be experimenting with these soon and we’ll let you know how we go!
Good luck to our junior team in the High School UAV Challenge this weekend
We are really excited that Cassandra and Elizabeth have entered a CanberraUAV Junior Team in the high school UAV Challenge and they have made it through to the competition this weekend in Queensland!
They have been working hard on developing an autonomous mission with their 3DR Solo for the main mission. They have also done some great work designing and 3D printing their own payload release mechanism and a clever protection device for their payload. Good luck to you both!
Communication, communication, communication!
For the last few weeks the CanberraUAV skunkworks has been busy working on solutions to the 2020 Medical Rescue UAV Challenge problems.
We see the 12 km video link between the Quadcopter and the ground control station as the biggest challenge for 2020. The Quad will be in a shed videoing ‘Outback Joe’ whilst sending video via one of our trusty Porter aircraft back to the ground station where it is being controlled from. We always try to have redundancy in our systems, so we’re working on two seperate communications links to achieve this. One of these makes innovative use of our trusty RFD900Xs and another one that uses some amazing new radios that have been kindly donated to us by Airborne Innovations and MicroHard. These radios are video and audio capable with telemetry & control and an option for manual control with an SBUS passthrough module. They claim solid video data rates at 5 miles with basic antenna; Airborne Innovations has donated some pretty special antennae to boost that range. We’re pretty excited to get our hands on them! More on these when we have tested them.
Tridge and Matt have been working hard on developing a new video encoder that can reduce the bandwidth and lower the latency sending video back to the ground station over RFD900Xs with MAVlink. We’ve made a good start but we have quite a way to go!
We’re hoping to give the Airborne Innovations and MicroHard pMDDL2450 radios a test this weekend, so we’ll report back then.
Here’s a taster of what else we’ve been working on for the next update!
Getting mid-air launching right
Peter and Jack have been working hard on repairing and modifying the Boomerang and launch mechanism to make the Quad launching reliable. They have fitted a servo hold / release mechanism for the Quad which solves the problems that we had last week where the Quad was blown off the Boomerang by the prop wash and air flow. Combined with Peter’s ‘punch’ launch code this is now working well and reliably. One step closer to saving Outback Joe in the 2020 Medical Rescue UAV Challenge!
