I have been thinking about sending my X-UAV Talon on a 100km flight and despite pondering it for a long time today I hit the milestone in an unplanned way.

During a checkout flight for our spare support aircraft for West Coast UAV's entry in the 2016 Medical Express challenge I noticed that we had an amazingly efficient combination of airframe/motor/prop and the numbers were looking good for a 100km run.

So up the Talon went carrying 20AH of 3S Multistar batteries driving a NTM1100KV motor and APC 12x10 prop. The average speed was kept low and despite encountering some airspeed measurement issues it crossed the 100km mark at just over 1 hour and 40 minutes airborne.

Logfile Link

The landing was unfortunately a bit hairy and fast as the voltage had dropped fairly low and the airframe copped a few dents but really happy to have knocked over the 100km milestone.

Here at team West Coast UAV we've been hard at work integrating all the different requirements for the 2016 Medical Express Challenge to be held in Queensland, Australia later this year. One of the key requirements is to accurate locate poor old Joe.

We know Joe is within 100m of his reported location, and he will be wearing his trusty blue jeans. Our approach is to take an image of the entire area from an altitude of 250 metres. Once Joe is identified we can then using the aircraft’s known position and attitude we can determine his exact location.

Our imaging system is responsible for finding Joe’s location to within 10 metre accuracy. This must be done quickly and with potentially limited bandwidth (as low as 3Kbit a second) which has led us to refining and developing a number of novel solutions.

Just as important. is a streamlined workflow to minimise the time from initial image capture to landing waypoint upload. For this we have developed an integrated web browser solution that interfaces with the many components involved in imaging and locating Joe.

West Coast UAV is pleased to have completed the Deliverable 2 Technical Report and submitted this to the competition organisers.

This report details the our UAV systems that will be used the complete the mission and our risk management approach.

The team has put in a lot of work to get to this stage. Our key achievements have been:

• Developing and testing a multi-point comms network to allow over-the-horizon communications to our retrieval aircraft,
• Implementing a system to reverse the thrust of our retrieval aircraft so that it can achieve a very steep glide-slope and land within a tight space,
• Tested multiple configurations of aircraft such that the retrieval aircraft can take-off in a short distance, whilst maintaining high-airspeeds and efficient cruise.

You can read our full report WestCoastUAV Deliverable 2 and read our blog at westcoastuav.org

Team West Coast UAV achieved one of our major milestones during testing on the weekend, controlling multiple UAVs through a multi-point comms network suitable for the 2016 Outback Challenge. 

One of the main challenges for our mission will be establishing reliable communications between our ground station and the retrieval aircraft when it lands at a distance of over 10 km away. To solve this we will keep our support aircraft flying in the air and use this to relay the telemetry from the ground station to the retrieval aircraft on the ground.

On the weekend we successfully demonstrated the relay concept in the field using a 1W 900 Mhz radio link between the ground station and the support aircraft (Ben’s X-UAV Talon), and then relayed to the second telemetry link to the retrieval aircraft (Steve’s Crash Test Hobby Reaper) using a 25mW 433 Mhz radio link. Both aircraft were fully controllable in autonomous flight. The retrieval aircraft was flown to a distance of 700m from the support aircraft and still maintained a reliable link.

To read more see the full blog post at our website:

http://westcoastuav.org/2015/09/15/major-milestone-comms-network-controls-multiple-uavs/

Until recently my main TX was a Turnigy 9X and I (like many others) was using a hacked in 6 position POT switch to select modes on my various aircraft. Unfortunately the 9X has died so has been replaced by a shiny new 9XR. Rather then hack apart the 9XR (too pretty) I wanted to experiment with using the existing controls to select modes on my aircraft. I have seen several tutorials on this but none met all of my requirements below. Apologies if I have simply rediscovered something already posted by someone else.

1. Not relying on guessing the position of the continuous POT switches
2. Gives a easy to read visual indicator of current mode
3. Uses only a single radio channel
4. All performed with the default software and hardware – no flashing/hacking required

The method I used was to combine the 3 position switch (ID0/1/2) with the Aileron Dir switch. Between these two switches there are six possible combinations which neatly matches the 6 modes of the APM ecosystem.

I am using an 8 channel system and wanted to only use one channel for mode. To do this I created a “fake” channel 9 representing the position of the aileron switch which I then mixed with the results of the 3 position switch to achieve 6 switch combinations.

Instructions

Step 1 – On the SETUP 02 page for the model in question change the Proto setting to add additional channels to the model (10CH in my example). As the hardware I use can only send/receive 8 channels these will be ignored by the TX/RX module.

Step 2 – on the MIXER page for the model Set the following Mixes (note that all values are minuses)
    CH5 -100% CH9 ID0
            -35% CH9 ID1
            -10% CH9 ID2

    CH9 -125% FULL AIL

This sets up the three position switch on channel 5 and then applies a large offset to the value from this switch based on the position of the Aileron Dir switch (CH9). The result is 6 possible channels as per the picture below that map neatly to the PWM inputs required by the APM. Note that you can set the actual mode to be whatever you want in MP.

One important note to consider – This switch combination has 2 very easy to use “panic” modes. At any time you can flip both switches up or both switches down with one movement that doesn't require much thought. I suggest you make sure that suitable modes are set up for these. My setup is to have FBWA (perhaps Stabilise for copter) when both switches are up and RTL when both switches are down. This came in handy the other day for me when due to a bad throttle calibration I had a copter shoot into the air uncommanded as soon as it armed - all I had to do was whack both switches down and let the APM do the rest all the way back to landing.

In theory the same mix should work on any TX with these capabilities. I hope this is helpful to people and happy to discuss or take feedback if there are better ways.

MAVProxy is powerful ground station software that excellently complements your favorite GUI ground station, such as Mission Planner, APM Planner etc. A key driver for me to look into MAVProxy was it's capability to forward the signal from your UAV over the network via UDP to multiple other ground station software on other devices. For example; you can run a ground station on a laptop next to your antenna and forward via wifi to a smartphone/tablet which lets you easily relocate to launch into wind before heading back to your fixed antenna. I have also used it to send telemetry data to a friend acting as spotter several kilometers away (via 4G vpn) during a longer flight so that he could monitor the entire flight and determine where to look to find the aircraft in flight.

Alas it is not the easiest to understand how to run on Windows and I had no luck finding a single step by step guide for the non technical, so I have had a go at creating one. This guide will let you successfully set up MAVProxy to allow forwarding via network interfaces and usage via command line. There may be other ways to get this running and you may need other packages as per the official MAVProxy documentation at http://tridge.github.io/MAVProxy/ in order to use more advanced functions. No warranty responsibility for damage etc. Full credit to Andrew Tridgell and all other contributors to MAVProxy and the other software used here.

Step 1 - Check you can connect to your UAV

Before starting anything make sure you can make a direct connection to your aircraft with your normal Ground Station software on the PC in question. Check that you know the correct COM port and baudrate for the modem attached to your laptop as we will need that info later.

Step 2 - Install Python

Download and install Python 2.7 - Windows x86 MSI Installer works regardless of OS/CPU type. Install with default settings to C:\Python27\

Step 3 - Install Pyserial

Download and install Pyserial 2.7 - Win32 for Python 2.x (2.4...2.7) - Use default settings to the C:\Python27\ directory.

Step 4 - Install and set up MAVProxy

Download MAVProxy latest .tar.gz file and extract (Install WinRAR if you have no suitable archive extractor) to C:\Python27\

Once extracted you should be able to open up the path C:\Python27\MAVProxy-1.3.3\MAVProxy and see a file called mavproxy.py

Right click on mavproxy.py and select Edit with IDLE. On line 20 of the file remove the # in front of the line sys.path.append(os.path.join(os.path.dirname(os.path.realpath(__file__)), '..')) so that it appears as below

Step 5 - Install pymavlink

Download pymavlink latest .tar.gz file and extract to C:\Python27\MAVProxy-1.3.3\MAVProxy

This will create a directory in the above folder called something like "pymavlink-1.1.29". Rename this folder to pymavlink.

Step 6 - Ready to run!

Check your radio modem is connected via USB, the aircraft modem and APM are powered and ensure any other ground station software is closed.

Open a command prompt window (Click start, type cmd and then press enter) and then enter cd "C:\Python27\MAVProxy-1.3.3\MAVProxy" and push enter. The command prompt will open that directory.

Then type mavproxy.py --master="com14" --baudrate 57600 (replacing the com port and baudrate with your local modem settings) and then push enter.

If everything has worked you should see MAVProxy start up and some basic flight data such as mode and current waypoint appear. Occasionally some data does seem to result in glitching and odd characters appearing onscreen but this does not seem to affect reliability or performance.

Enter a command such as mode FBWA  and press enter. You should see MAVLink report the mode change and notice your aircraft change behavior into that mode.

The full list of MAVLink commands can be found here if you want to experiment further with the command line.

To exit MAVLink press Control+C together.

Step 7 - Forwarding over network

To forward the MAV data over the network including to a local program on your PC we simply need to add some extra parameters when starting MAVProxy via the command line. 

To connect with a local ground station software such as Mission Planner start MAVProxy as above with the command mavproxy.py --master="com14" --baudrate 57600 --out 127.0.0.1:14550 and press enter.

Then open Mission Planner and select UDP and click connect. Clink OK on the default prompt for port number (14550) and you should see mission planner start downloading parameters and connecting to your UAV.

Finally you can add the IP address of any computer to forward the telemetry stream onwards to other ground stations.

1) On the local network/wifi you will need to ensure there is no firewall on the client PC stopping the incoming stream to your ground station software.

2) Add --out IP_ADDRESS:14550 to the end of the mavproxy.py command. You can add as many separate --out parameters as you want depending on how many extra ground stations you are running.

3) Set each ground station to listen for UDP packets on port 14550

Step 8 - Simple startup using a batch file

To simplify the starting up of MAVProxy I have written a simple 5 line batch file:

 Mavproxy Startup Batch File

You should edit this to reflect your local port, baudrate and include any additional IP addresses to forward the data to.

Simply save this anywhere and double click to start MAVProxy (assuming you have followed the instructions above).

I really hope this is helpful to some people. It took me a while to figure it out and hope my learning experience can benefit others. 

I thought I would share my recent experience getting back into UAV/RC. HI got started in this a few years back as a uni project where I wrote a FBW / Stabilization program on a PICAXE PIC chip using the ArduIMU as a sensor package. 

More recently I have started again with a Bixler 2 and Pixhawk where I have been learning the world of APM (and re-learning my rusty RC skills). It was certainly a learning experience - my first ever auto flight flew away out of sight due to reversed rudder settings. Lucky for me the APM eventually managed to turn the plane around and it calmly flew back to home after a few very tense minutes packing up and go searching for the aircraft in the suburbs.

Over the Easter break I took a trip down to Albany in Western Australia and obtained some HD videos around the beaches there which I've attached below:

First Camera Equipped APM Flight on my Bixler 2 - Snapshot is looking over Bald Head.... next stop Antarctica.

Telemetry Range Tests around whaling station - This includes a crash due to stalling at the end of flight. First time with dual 2.2AH batteries and I underestimated the effect of the extra weight on stall speed.

Flying Over Goode Beach - A nice tour of the Goode Beach area in Albany. This video includes an overlay of the MP HUD from the telemetry data on the flight.

Unfortunately on my last flight (not shown as camera was lost) I encountered a major problem in the air which I suspect was motor/ESC failure. The resulting stall and crash from high altitude destroyed the aircraft but fortunately hit the ground only about 100m from me and I was able to recover all of the electronics except the camera. A new Bixler is on my kitchen table at home under construction and I hope it lasts longer and I can learn the lessons for both build and flying.

(Standard safety note - you will notice that we are launching/landing in a small carpark and using the nearby road at times. This is an extremely quiet rural road and I had a spotter who could see up and down the road to ensure we didn't get in the way or get hit by traffic)