UWSim /g500/pose doesn't echo anything

Hello,

I want to compare my algorithm's tx ty tz qx qy qz qw to the groundtruth in UWSim.

I created my robot and the environment, however, when I run

\$ rostopic echo /g500/pose


I get absolutely nothing. What am I missing?

I created a simple teleoperation where I can control my robot using arrow keys and W A S D. So I was expecting the pose to show up.