# LPE and attitude\_estimator\_Q

**URL:** <https://discuss.px4.io/t/lpe-and-attitude-estimator-q/4655>\
**Category:** PX4 Autopilot\
**Created:** [October 12, 2017, 8:30pm UTC](https://discuss.px4.io/t/lpe-and-attitude-estimator-q/4655 "2017-10-12T20:30:11Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Mario1577](https://discuss.px4.io/letter_avatar_proxy/v4/letter/m/8e8cbc/32.png) [@Mario1577](https://discuss.px4.io/u/Mario1577)\
**Post date:** [October 12, 2017, 8:30pm UTC](https://discuss.px4.io/t/lpe-and-attitude-estimator-q/4655/1 "2017-10-12T20:30:11Z")

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Hello!

Maybe they’re silly questions but …

What is the function of lpe and attitude\_estimator\_Q in the pixhawk?

the estimators are filters for the sensors?

what os the difference between lepe and attitude\_estimator\_Q?

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**Author:** ![abdullahmohiuddin](https://discuss.px4.io/letter_avatar_proxy/v4/letter/a/41988e/32.png) [@abdullahmohiuddin](https://discuss.px4.io/u/abdullahmohiuddin)\
**Post date:** [October 15, 2017, 4:31am UTC](https://discuss.px4.io/t/lpe-and-attitude-estimator-q/4655/2 "2017-10-15T04:31:45Z")

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Hi,

I think, LPE is an extended kalman filter, while attitude\_estimator\_Q is a complimentary filter.  
I like this question, I hope there will be further useful discussion here.

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**Author:** ![AlexisTM](https://discuss.px4.io/user_avatar/discuss.px4.io/alexistm/32/3456_2.png) [@AlexisTM](https://discuss.px4.io/u/AlexisTM)\
**Post date:** [October 15, 2017, 11:24am UTC](https://discuss.px4.io/t/lpe-and-attitude-estimator-q/4655/3 "2017-10-15T11:24:36Z")

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LPE fuse the sensors to get the position of the UAV.  
Attitude estimator fuse the imu to get the attitude of the UAV.

An alternative is EKF2:

EKF2 fuse the sensors to get the position and the attitude of the UAV.

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**Author:** ![Mario1577](https://discuss.px4.io/letter_avatar_proxy/v4/letter/m/8e8cbc/32.png) [@Mario1577](https://discuss.px4.io/u/Mario1577)\
**Post date:** [October 19, 2017, 9:58am UTC](https://discuss.px4.io/t/lpe-and-attitude-estimator-q/4655/4 "2017-10-19T09:58:55Z")

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Hello! @AlexisTM

Lpe and attitude estimator, Are they kalman filters?

Thanks and regards!

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**Author:** ![AlexisTM](https://discuss.px4.io/user_avatar/discuss.px4.io/alexistm/32/3456_2.png) [@AlexisTM](https://discuss.px4.io/u/AlexisTM)\
**Post date:** [October 19, 2017, 10:18am UTC](https://discuss.px4.io/t/lpe-and-attitude-estimator-q/4655/5 "2017-10-19T10:18:27Z")

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[LPE](https://github.com/PX4/Firmware/blob/c28cd76e5f9fd3c10b2e682312acddb42f44e576/src/modules/local_position_estimator/BlockLocalPositionEstimator.cpp) and [Attitude estimator](https://github.com/PX4/Firmware/blob/c28cd76e5f9fd3c10b2e682312acddb42f44e576/src/modules/attitude_estimator_q/attitude_estimator_q_main.cpp)

What are you trying to do?

The actually supported estimator is EKF2.

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<div class="post-metadata">

**Author:** ![Mario1577](https://discuss.px4.io/letter_avatar_proxy/v4/letter/m/8e8cbc/32.png) [@Mario1577](https://discuss.px4.io/u/Mario1577)\
**Post date:** [October 19, 2017, 7:28pm UTC](https://discuss.px4.io/t/lpe-and-attitude-estimator-q/4655/6 "2017-10-19T19:28:39Z")

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I am sending mocap data to pixhawk, I have to use LPE and Q attitude estimator, so I didn’t know what kind of filter was LPE.

[https://dev.px4.io/en/advanced/switching\_state\_estimators.html](https://dev.px4.io/en/advanced/switching_state_estimators.html)

Thanks @AlexisTM and @abdullahmohiuddin