# Precision landing problem

**URL:** <https://discuss.px4.io/t/precision-landing-problem/27416>\
**Category:** PX4 Autopilot\
**Created:** [May 13, 2022, 2:24pm UTC](https://discuss.px4.io/t/precision-landing-problem/27416 "2022-05-13T14:24:47Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![JAEPIL\_YOO](https://discuss.px4.io/user_avatar/discuss.px4.io/jaepil_yoo/32/5794_2.png) [@JAEPIL\_YOO](https://discuss.px4.io/u/JAEPIL_YOO)\
**Post date:** [May 13, 2022, 2:24pm UTC](https://discuss.px4.io/t/precision-landing-problem/27416/1 "2022-05-13T14:24:47Z")

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Hi.  
I’m testing precision landing.  
Sometimes it feels like it’s working very well  
On another day, we land far away from beacon.  
(On a windy day, it was confirmed that beacon was entered correctly in PX4 LOG.)  
I installed an irlock at the bottom of the center of the aircraft, a distance measurement sensor, and entered the RTL option.

PARAMETER has changed two things as below.

PLD\_FAPPR\_ALT : 0.1 (default) -\>1 and  
PLD\_HACC\_RAD : 0.2 (default) → 1.5 changed.

I think there is an optimized parameter value, can you tell me?

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**Author:** ![Yeshes](https://discuss.px4.io/user_avatar/discuss.px4.io/yeshes/32/18777_2.png) [@Yeshes](https://discuss.px4.io/u/Yeshes)\
**Post date:** [June 12, 2025, 11:33am UTC](https://discuss.px4.io/t/precision-landing-problem/27416/2 "2025-06-12T11:33:31Z")

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Hello Jaepil\_yoo.

Good Day.

It looks like you were able to precisely land the drone using IRLOCK sensor in PX4 firmware. Even i am trying the same but the drone doesnt land precisely, but land normally without the help of IR Sensor. After reviewing multiple time, it looks like the IR lock driver is not being started from PX4 end even after forcefully starting it.

I would like to know how did you achieve?

Any help would me much appreciated.

Thankyou

Regards,  
Yeshes P

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**Author:** ![Dazz](https://discuss.px4.io/user_avatar/discuss.px4.io/dazz/32/19687_2.png) [@Dazz](https://discuss.px4.io/u/Dazz)\
**Post date:** [June 13, 2025, 8:47pm UTC](https://discuss.px4.io/t/precision-landing-problem/27416/3 "2025-06-13T20:47:47Z")

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Hi Yeshes,

What you can try to do is:  
Turn on the drone  
Open MAVlink console from QGC and type:  
`landing_target_estimator status` (to see if it is running or not)  
`landing_target_estimator start`

Fly the drone and perform a precision landing through Precision Landing mode. Meanwhile, the drone is landing, you can check if the irlock is working correctly, running this in the MAVlink console from QGC:

`listener irlock_report -n 500`

if everything works you should see the report of it.

if you see ‘‘`never published`’’, run the command again while the drone is landing.

Hope this helps!

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**Author:** ![Yeshes](https://discuss.px4.io/user_avatar/discuss.px4.io/yeshes/32/18777_2.png) [@Yeshes](https://discuss.px4.io/u/Yeshes)\
**Post date:** [June 23, 2025, 12:38pm UTC](https://discuss.px4.io/t/precision-landing-problem/27416/4 "2025-06-23T12:38:11Z")

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Hi Dazz, thankyou for your valuable inputs.

The drone performs the precision landing only when the IR Lock driver is started manually from the MAVlink Console. I have added **irlock start -X** and **landing\_target\_estimator start** in the SD card of the flight controller inside extras folder to start on boot, but IR lock fails to start on its own.

Is there a way for it to perform automatically similar arducopter/ mission planner way?

Thankyou

Regards,  
Yeshes P