What is vehicle_attitude_setpoint.thrust?

version: 1.5.5

In vehicle_attitude_setpoint.msg

float32 thrust # Thrust in Newton the power system should generate

I think this variable is not a thrust in Newton.
It is from 0 to 1.

e.g. I want to generate a thrust 2N. How to set it?

Unfortunately it’s just a normalized value.

Can we find a mapping from the thrust required to this normalised value except the dynamic identification?