# Unable to set the value of EKF2\_GPS\_CTRL while using "UM982"

**URL:** <https://discuss.px4.io/t/unable-to-set-the-value-of-ekf2-gps-ctrl-while-using-um982/34405>\
**Category:** PX4 Autopilot\
**Created:** [September 21, 2023, 2:34pm UTC](https://discuss.px4.io/t/unable-to-set-the-value-of-ekf2-gps-ctrl-while-using-um982/34405 "2023-09-21T14:34:44Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![MuhammadBilal1](https://discuss.px4.io/letter_avatar_proxy/v4/letter/m/3ec8ea/32.png) [@MuhammadBilal1](https://discuss.px4.io/u/MuhammadBilal1)\
**Post date:** [September 21, 2023, 2:34pm UTC](https://discuss.px4.io/t/unable-to-set-the-value-of-ekf2-gps-ctrl-while-using-um982/34405/1 "2023-09-21T14:34:44Z")

</div>

Hi,  
I am trying to use [H-RTK Unicore UM982 (Dual Antenna)](https://docs.holybro.com/gps-and-rtk-system/h-rtk-unicore-um982/overview) GPS Antenna to fix the yaw issues I were having due to the higher values of EMF.

**Here are the details of my setup:**  
**Firmware:** PX4 1.14.0rc  
**AutoPilot:** Holybro Pixhawk 6C  
**Airframe:** Quadrotor x (Generic Quadcopter)

**Issues:**

- Unable to set the value of “EKF2\_GPS\_CTRL” to “Dual Antenna Heading” (8).
- Unable to arm the drone while in “Position” mode, upon pressing the “arm” button from remote, the GPS red light becomes flashing red in fast and a beep came. No error on QGC screen. Drone is arming if I arm it in the “Altitude” flight mode.

I can successfully set the value of the below parameter as asked in the [documentation](https://docs.px4.io/main/en/gps_compass/rtk_gps_holybro_unicore_um982.html#px4-configuration), but getting a message while trying to set the value of “EKF2\_GPS\_CTRL”.

- [SER\_GPS1\_BAUD](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#SER_GPS1_BAUD) → 230400
- [GPS\_1\_PROTOCOL](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#GPS_1_PROTOCOL) → 6: NMEA
- [GPS\_YAW\_OFFSET](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#GPS_YAW_OFFSET) → 90

Whenever, I try to set the value of “EKF2\_GPS\_CTRL” to “8” (Dual Antenna Heading), the value automatically goes back to “15”.

 ![Screenshot (56)](https://discuss.px4.io/uploads/default/original/2X/7/7a20f2dd422de4d721001fc957ea6575beea0439.png)