Dynamic inertial profilometers

Dynamic inertial profilometers are the most common devices used nowadays in road network surveys to determine pavement surface roughness. The inertial profiling system is mounted on a vehicle hence, they are called high-speed profilometers. 

All inertial profilometers available today, except one, the longitudinal pavement analyser, APE, use accelerometers, which provide the horizontal plane of reference in a non-contact manner. 

The accelerometer is a transducer designed to measure vertical acceleration and used to establish the inertial reference and effectively the response of the vehicle to the road surface (instant height of accelerometer in the host vehicle). The vertical distance between the accelerometer and the travelled surface is measured by displacement transducers or sensors (laser, acoustic or infrared sensors) and the distance travelled by distance transducers. Eigure 16.29 shows an accelerometer and a single sensor mid-mount on a vehicle. 

The accelerometer s and sensor s signals are all combined by computer software and produce the longitudinal profile of the travelled surface. 

One laser sensor determines the longitudinal pavement profile in one location (path), whereas any number may be used to capture several longitudinal locations and hence the transverse profile may be determined as well. The laser sensors are usually mounted at the front of the vehicle. 

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