🚀 Feature Request

Should add a 3x3 covariance matrix to all IMU hardware templates. When specifying an IMU in the config file, a 3x3 covariance matrix should be added for each of the sensors that the IMU contains. For example, the built-in accelerometer should only contain a covariance matrix for linear acceleration. By contrast, the NavX and Pigeon IMUs should contain covariance matrices for each angular velocity, linear acceleration, and orientation (magnetometer).

See sensor_msgs/Imu.