Precision Landing Help needed

Hi @ThomasSFL find attached the PARAM file from my testing!

samucs.param (13.6 KB)


I have the same request and made it some time ago. It would be great to have some way of knowing if the beacon has be acquired or not. Having this feature would help us greatly in developing better landing pads and work to make the prec landing as close as possible to 100% reliable.

Having a variable that tells the user if the target is acquired or not in real time during landing would help operator to decide wheter the landing is ok or needs to be done manually. Expecially in confined areas.

We use a companion too, so even a pin on pixy would be ok.



You could stream logs over mavlink by setting LOG_BACKEND_TYPE=3, then look at the PL messages. You can then interrogate the TAcq field that tells you whether you have the target acquired. Ideally you could get this over a mavlink stream without having to look at the logs in realtime - it could be added to SRx_EXTRA3 stream for example.

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@ThomasSFL Hum that’s weird. I also had a lot of interference in bright sunlight when metal is reflecting the sun. The pixy would get easily confused. Long time ago, I read the the beacon was doing some kind of frequency pattern but I could not verify this… Feedback on this ?

Thanks for your suggestion, once i set log_backend to 3 where i can look at logs in real time using mission planner on my pc?
Is there a file written in realtime during flights?


I don’t know how it works if streaming to a GCS like mission planner. Normally mavlink log_backend is used to stream to a companion computer onboard, through mavlink-router or dflogger, something like that. When using mavlink-router, it just saves a log file to the filesystem which you can then transfer and load into a GCS for graphing, or you can use something like this:

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Hi Thomas, we are working on having precision loiter with IR lock. The PLND_ENABLED = 1 and PLND_TYPE = 2. We are getting all the values under PL as it should. But when we put it on prec.loiter it does not hold on to the beacon. It just drifts. Is there anything we are missing out on?

Then it worked for me.

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Have you setup a channel option to 39?

@mtbsteve we already have it set on 0. @fnoop Yes it is setup. But it still drifts and its not holding onto the beacon

@Andreas_Krauchi @anon67614380 @Kiwa21 @nish

Sorry for the delay! I was on vacation, and now I am avoiding a hurricane.

I will get back to you soon!

Iam testing the IR-Lock for the first time.
The IR-Lock is recognized by the Pixhawk Pl Heal is 1
But the TAcq is always zero even when the copter starts and lands over the beacon.
The IR-Lock itself can find the beacon I have tested that with the piximon software.
IR-Lock firmware is 1.0.1
The firmware on the Pixhawk2 is 3.5.2.
No Rangefinder is installed. Is it necesarry to get TAcq or px py values?

@Spatz Hi! Yes, a rangefinder is required if you are using IR-Lock and Copter 3.5.2.

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Finally back from the hurricane! Thank you for your patience.

Do you have a log file from a precision landing/loiter test?



Thank you so much for your patience! I am back from the hurricane.

Please make sure you are using MarkOne if you want reliable detection performance in bright sunlight. The other beacons are not capable of the same detection performance.


@anon67614380 @fnoop

I didn’t know about that feature! Great stuff!!


Sorry for the delay! I am back after the hurricane.

@fnoop provided some great feedback regarding the live streaming of . I hope this is helpful.

I wish we could check your IR-LOCK and MarkOne setup in-person, but we are limited to e-mail/forum discussion. The best ways for us to diagnose detection issue are:
(1) Upload a log and video of the precision landing test where you suspect detection issues
(2) Upload a recording of Pixymon video/detection feed

I would seriously enjoy checking those files/videos to try to diagnose the issue.

Regarding the reliability of MarkOne detection performance in different lighting conditions: the only issue we are aware of is when a reflective surface is placed IN FRONT OF the beacon (i.e., clear acrylic placed in front of beacon). Reflective surfaces NEARBY the bacon are completely ok.


Thx thomas!

So how can we record the Pixymon video/detection feed while on the drone?
I have a Ubuntu companion pc onboard an could record the stream live while
landing. Do know how to record this onboard the companion do you have a tool
for that?


Here is an example where the copter near the ground starts to re-climb up a few cm and then finally lands on the ground.
Can you explain this behavior…



here we go just from a flight of today another problem with the IRLock landing.
Here is the bin file:

Sometimes the copter does a correction to the wrong side and sometimes it works fine.
As soon as it does the wrong correction the IRLock is not able to realign the copter twoards
the beacon.