GPS and Accelerometer Sensor Fusion with a Kalman-Filter

Good Morning,

i am having troubles understanding the Kalman-Filter implementation in px4. What i don’t understand is, if the Kalman-Filter can be used in combination - like GPS & IMU for Dead Reckoning / better Positioning

PS:https://docs.px4.io/v1.9.0/en/advanced_config/tuning_the_ecl_ekf.html

greetings