Sound is the result of pressure variations or fluctuations - the physics is the same, more or less for low, high or ultrahigh frequencies. Propagation, absorption, attentuation are all quite dependent on frequency but it would seem that the units of measure are the same.
As you are aware the decibel level depends on a point of reference. You'd need to know what point of reference is used for the sensors you are considering. It's possible that there is an understood industry standard that is used - so everyone in that industry assumes a reference point without actually stating it.
There's lots of good information available but much of it in the form of books - protected by copyright (unfortunately for us). You might google on "sound pressure level" and "sound power level" - you might be fortunate enough to find discussions that will help. Looking thru a physics book or two at a local library might help get you going too.