hector_mapping doesn't update robot pose with insufficient features

I am trying to use hector_mapping to create a 2D map using a UGV. I wanna first try it in gazebo before testing it on a real robot. My robot configuration includes an IMU, 2D laser, and data from wheel encoders. I am running `robot_pose_ekf` package to update `odom->base_footprint` frame transform and want to use hector_mapping to update `map->odom` frame transform. Also, I'm using husky robot in gazebo and start the simulation with robot sitting outside willowgarage model. (FYI, I did the same with gmapping and everything just worked fine) In RViz, the robot doesn't move until I drive the robot inside the building in Gazebo and that's when robot actually starts driving in RViz and starts building a map. But then as soon as I drive the robot outside the building, robot stops updating its pose in RViz and stops building the map. I believe this is caused due to insufficient laser features when I drive outside (only a wall on one side), but also `robot_pose_ekf` is updating `odom->base_footprint` transform. What could be causing the robot not to move outside the building. Here's a copy of the launch file I'm using, any advice will be appreciated.