GPS and IMU localization

edit

Hello, I am pretty NEW to ROS... My robot is supposed to do autonomous navigation outdoors. It has GPS, IMU, Lidar and stereo camera. I am using robot_localization package in order to localize the robot. I aslo have a pgm map file. and I am publishing it to /map topic. I reached the part where I need to tune the navsat_transform_node. However, I am pretty lost. I am recieving the data needed from the GPS and IMU on /fix and /data/imu and the map on /map topic... however, I am not sure what to do next? and there is a lack of good tutorials for using gps with ros, or I am not finding any.