Lidar landing with APM:Plane

Over the last couple of days I have been testing the Lidar based auto-landing code that will be in the upcoming 3.1.1 release of APM:Plane. I'm delighted to say that it has gone very well!

Testing has been done on two planes - one is a Meridian sports plane with a OS46 Nitro motor. That is a tricycle undercarriage, so has very easy ground steering. The tests today were with the larger VQ Porter 2.7m tail-dragger with a DLE-35 petrol motor. That has a lot of equipment on board for the CanberraUAV OBC entry, so it weighs 14kg at takeoff making it a much more difficult plane to land well.

The Lidar is a SF/02 from LightWare, a really nice laser rangefinder that works nicely with Pixhawk. It has a 40m range, which is great for landing, allowing the plane plenty of time to lock onto the glide slope in the landing approach.

APM:Plane has supported these Lidars and other rangefinders for a while, but until now has not been able to use them for landing. Instead they were just being logged to the microSD card, but not actively used. After some very useful discussions with Paul Riseborough we now have the Lidar properly integrated into the landing code.

The test flights today were an auto-takeoff (with automatic ground steering), a quick auto-circuit then an automatic landing. The first landing went long as I'd forgotten to drop THR_MIN down to zero (I normally have it at 20% to ensure the engine stays at a reasonable level during auto flight). After fixing that we got a series of good auto flights.

The flight was flown with a 4 second flare time, which is probably a bit long as it allowed the plane to lose too much speed on the final part of the flare. That is why it bounces a bit as it starts losing height. I'll try with a bit shorter flare time tomorrow.

Here is the video of one of the Meridian flights yesterday. Sorry for missing part of the flight, the video was shot with a cell phone by a friend at the field.

Here is another video of the Porter flying today, but taken from the north of the runway

I'd like to thank Charles Wannop from Flying Finish Productions for the video of the Porter today with help from Darrell Burkey.

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  • Andrew,

    We did some test flights with an SF02 last weekend and got some good results.  We are using a PixHawk loaded with 3.1.1beta and the output from the dataflash logs is shown below.

    I've pulled the data into excel and adjusted the scales to get the graph below.  We are just looking at three instances within the flight where we did a low ground pass below the threshold we had set for the sonar - 10m.

    The GPS and baro appear to be exactly the same - are they really that accurate?

    When we are plotting the baro reading is it the raw baro reading or is it the adjusted and filtered altitude?

    The sonar is reading too low - is this fixed with the sonar offset command?

    We are getting there - thanks for the assistance.

  • Thanks tridge!.
  • Developer


    The 915MHz 3DR radios are setup for Australia. The Australian ISM band near 900MHz is from 915 to 928.

    The mobile phone network uses frequencies below 915MHz.

    Cheers, Tridge

  • Todd: You cant use 915 because thats the reserved for mobiles in Australia. To confirm goto the 3dr store to confirm.

  • Its seem the SF02 is out of stock at the moment. Does anyone know of a supplier source for this as I want to get one ASAP. Thanks.

  • Developer

    Hi Gray,

    We used the 3.3V ADC (the 5 pin DF13) and set RNGFND_PIN=13. We set RNGFND_SCALING to 12.12. We used the ADC as we don't have a spare UART on the Pixhawk (as we have two telemetry radios and have two GPS modules).

    Cheers, Tridge

  • Andrew,

    How did you wire up the SF02?

    Did you use the serial port or the ADC on the pixhawk?

    If you used the ADC which pin did you connect to with ArduPlane 3.1.1-beta?


  • Hi Andrew,


                                    Sorry to be off topic, but do you have any advice as to  which one of these should I buy for use in Jindabyne Australia, is there any setup involved?.



    I use the HKpilot mega with a quadcopter and am aiming to setup 'follow me' mode.

    Also if i bough one of these could i use it to control the quad over long distances instead of my tx/rx or would it be to hard to set up?.

    Are there any clubs in canberra where i could come along and learn in person over the next few months?


    Thanks for your help,




  • Hi Tridge !

    Thanks for all your contribution for the benefit of the RC community. Hats off to you man !

    I am in the flying field at the moment and just did a test flight using Arduplane 3.1.0, APM2.52, uBlox-6M GPS and Sky Eye EPO FPV/Glider w/Flaps 2000mm,  compass disabled, sonar installed but disabled, airspeed sensor installed but disabled at the moment. With default parameters it did quite well in stabilized and auto mode.

    Pls suggest If I can use sonar for auto landing. My APM is quite away from the large current carrying wires , should I try auto take off by enabling compass ?

    I am also taking with me a high 70'' winger trainer with OS46 engine, if every thing went well I shall also give a try to that also.

    Did you shared your telemetry flight logs at Droneshare ? Pls give link if yes and pls provide your parameters of your (Meridian sports plane with a OS46 Nitro motor)

  • 100KM
    I'm so excited about this!
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