Handling No Data during Slam

edit

Hi,

i am using Cartograper in Online Slam mode for a simulated robot that is supposed to navigate in a unknown road-like environment. Inputs are Odometry from simulated wheelencoders, Lidar and a Roaddetection. Lidar and Roaddetection are converted into one PointCloud2 and then passed to cartographer. In this Usecase it is not unlikely, that either the road-lines miss, or that every object is in the deadzone of the lidar.

In this scenario cartographer drops the map->odom transform and my robot slides unpredictably in rviz(obv in gazebo it drives normaly) untill i get data from the sensors. I dont really understand, why cartographer drops the transform, i assumed, that it could handle these scenarios by relying on odom only.

Is there any way to prevent that?

Thanks in advance, let me know if you need any data from me

EDIT:

i get the following error as soon as the transform gets dropped:

[ WARN] [1606233736.812276395, 5232.815000000]: W1124 17:02:16.000000 54728 tf_bridge.cc:52] Lookup would require extrapolation 26.700000000s into the past.  Requested time 5196.056000000 but the earliest data is at time 5222.756000000, when looking up transform from frame [odom] to frame [base_footprint]