Hello,

We are using a VN-100T, and we are getting a -π roll when the IMU is flat on a surface. In other words, Z is pointing down.

From looking a little at the code we found a couple of issues:

1. vectornav/vectornav/src/vn_sensor_msgs.cc

   Line 181 in 933af89

   // Quaternion NED -> ENU

   Orientation is always converted to ENU even if use_enu is false.
2. The above conversion actually breaks the orientation and causes the above mentioned issue. From our tests, the quaternion that arrives is already in ENU, so this conversion is redundant (nevertheless a conversion should exist if use_enu is false to turn it into NED).
3. Pose is always converted to ECEF, and afaik should also be in ENU.
   

   vectornav/vectornav/src/vn_sensor_msgs.cc

   Line 309 in 933af89

   geometry_msgs::msg::PoseWithCovarianceStamped msg;

   .

I don't mind issuing a PR, just would like to get assurance I am not missing something.