Is it possible to disable GPS source in EKF

Hello,

As far as I read, EKF uses various of sensors as source. Is it possible to disable GPS sensor programmatically but try to estimate current position using same EKF with the other sensors data like IMU etc.?

I need this for my project and somehow I need to disable GPS and observe the position estimation from EKF.

Cheers!

http://ardupilot.org/dev/docs/extended-kalman-filter.html#extended-kalman-filter
https://github.com/ArduPilot/ardupilot_wiki/blob/master/dev/source/docs/extended-kalman-filter.rst