Triple autonomous flights with MatrixPilot

Yesterday, my GentleLady sailplane, under the guidance of MatrixPilot running on a UAV Devboard with an EM406 GPS and Jordi's magnetometer, achieved 3 consecutive autonomous flights, with the transmitter off most of the time. The above picture shows the tracks of the three landings. Waypoints 18 and 19 were arranged so that the plane was supposed to land halfway between them. The closest landing was 6 meters from the target, the farthest was 21 meters.

Here is how the flight sequence worked:

1. Power up with Tx on.

2. Shut off Tx, this causes the fail safe on my Rx to trigger MatrixPilot to go into waypoint mode.

3. Hand launch the sailplane.

4. Sailplane makes two circuits around the field and lands.

5. Turn on the Tx, this puts MatrixPilot back in manual mode.

6. Turn off Tx, this puts MatrixPilot back in waypoint mode.

Repeat 3 times.

Here are the three flight paths around the field:

Here is the side view of the landings:

You can watch an animated view of the flight track on Google Earth with this kmz file: LOG00122.kmz.

The kmz files are produced by a tool that Peter Hollands put together that reads the telemetry and generates the kmz file. It has some nice features, including displaying the orientation of the plane, the waypoints, the wind vectors, and magnetic field vectors.

Simply download the kmz file and double click on it, Google Earth will open it. You will not see any flight tracks when you open it, but there will be an animation tool visible that you can use to animate the tracks, and/or select portions for viewing.

There will also be items in the layers visibility for you to turn the display of the tracks, waypoints, etc., on and off.

If you are interested in looking at them, here are two other files associated with the flights.

First, there is the raw telemetry file:


There is an excel spreadsheet with key telemetry items:


I want to thank all of the members of the UDB team for their contributions, especially Ben, Peter, Adam, Ric, Sid, and Rana. You guys are always there for me. Thank you Jordi, for your magnetometer breakout board.

And thank you very much, Chris Anderson, for your encouragement and for this website.

Best regards,

Bill Premerlani

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  • That is a sexy GUI!!
  • Billu Bhaiya, the above KML files are automatically generated by the Ground Station Beta developed by Automatik

    Thanks & Best Regards

  • T3
    Hi Michael,
    I am beyond impressed.
    How did you do that? Thank you very much for doing it.
    Best regards,
  • Developer

    Heres a first person view of the flight in google earth.

  • Admin
    :))) , I am not using 5th one yet. Before your I2C work on mag came out , I was thinking/assuming that all I need to do was measure PWM output and use it in specific range( reading out put) to trigger a specific output channel to trigger water bottle drop mechanism or landing gear or flaps( mainly) . Is this what you have in mind too? Since we have almost run out all PWM inputs in current setup, can we pls use with Analog/digital Mux/demux to combine (and expand up to 16 sensors in future) all such sensors in one clean package? thanks Bill Bhaiya for taking up this challenge too.
  • Hi Bill,

    congratulation !

    UDB seems to me like a chinese box : every day it shows some new hidden features.
    Still after a lot of flying with it I'm surprised on how you (and all the programmers staff) are able to improve it and on how well it was designed from start.

    Thank you very much.

    Best regards,

  • T3
    Hi Morli,
    The best way to interface the Maxsonar EZ0 to the UDB would be PWM, that should work just fine. That would be my preferred way to do it, if you are not already using all 5 of the PWM inputs. I am going to order one now.
    The SRF08 could be interfaced by I2C.
    Best regards,
    Billu Bhaiya
  • Admin
    or may be this dig-analg mux will make XL-maxsonar range finders work on I2C bus? If so can we add more analog sensors to it so that we can have sort of multiple sensor input panel? can any one advice / comment please? thanks
  • Admin
    BiIlu Bhaiya,
    I was hoping you would ask :)). some day soon and purchased the sparkfun Ultrasonic Range Finder - XL-Maxsonar EZ0 anticipating this, unfortunately seems it won't suit I2C (or will it suit?). hoping also that using this I2C to UART breakout , I.other who have the same might be able to use maxsonar EZ0.
    Quick google search shows that SRF08 Ultra sonic range finder are quite popular. The photo in the end of this document shows how it is mounted.
  • T3
    Hi Rana,

    Yes, your input is important feedback. It would be better if we had precise height information at a high bandwidth.

    I will add your suggestion of an I2C interface for an ultrasonic altimeter to my list of things to do.

    Is there a particular ultrasonic sensor that you would recommend?

    Best regards,
    Billu Bhaiya
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