What method do inertial lightweight profilometers use to measure surface profile?

Inertial lightweight profilometers measure surface profiles primarily through actual elevation measurements relative to a reference elevation. This method utilizes sensors and accelerometers to capture vertical displacements while the device is in motion, allowing for precise mapping of the surface texture and profiles of the pavement. By comparing these measurements to a reference point, the profilometer can generate an accurate representation of the surface's undulations and irregularities, which is critical for assessing pavement quality and performance.

Utilizing vehicle response, another approach mentioned in the options, would primarily focus on interpreting the behavior of a vehicle moving over the surface rather than obtaining direct measurements of elevation changes. Similarly, computer simulation does not involve direct physical measurement of pavement profiles but instead involves modeling based on theoretical knowledge or algorithms. Therefore, these methods are not suitable for the specific capabilities of inertial lightweight profilometers in measuring surface profiles.