what would happen if GPS is missing, while using robot_localization pkg

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Dear @Fetullah Atas, thanks a lot for your answer, one more question, if I use slam as the provider of the map for robot_localization pkg (I have already put the publish_tf_map in a false mode in SLAM setting), then How the switch from GPS to SLAM (for navigation) happen? thanks

If you find the answer useful please do upvote and mark it as accepted. For your follow up question, do you mean you set publish tf of EKF instance to false or SLAM ?

If you mean you disabled publish tf for SLAM, that’s good as it wouldn’t conflict with tf that’s being published by robot localization. Does your slam publish some sort of odometry or pose message ? If yes, you can input that as another source to EKF node, as for the switching, I am Not entirely sure about that but to my understanding, if you are fusing odometry/gps and odometry/slam into same instance, robot localization should be able to use what’s available, so I am not sure if a switching mechanism is required.

yes, i disabled publish_tf in SLAM, actually I am using RTABMAP and it publishes odometry information as well as pose. in which part of robot_localization i can give these data as input?! you mean, for example, instead of /warthog_velocity_control/odom , should I put /rtabmap/odom?! then what about the matrix? it will remain unchanged?

Append the slam odometry to existing list. so if you have warthog/odom as odom0, create another set of configuration with odom1. As for the matrix, select the true for the states that you think slam does a good job estimating. E.g x and v velocities.