To me, "ranging" means measuring the range to the target directly, not estimating it from other measurement types (bearings, for example). Can someone explain i

To me, "ranging" means measuring the range to the target directly, not estimating it from other measurement types (bearings, for example). Can someone explain if that's what the authors are doing here? Is it analogous to stadiametric ranging? I haven't read through this in depth, but I can't figure out what their method is.