Inertial Profiler

Inertial Profiler Mounted on NDT Van (Click to Zoom)

The inertial profiler is a vehicle-mounted set of sensors that records a pavement’s profile. This can be analyzed to calculate roughness indexes or perform aircraft acceleration simulations. In addition, another device’s response can be simulated on a profile with software. Effectively, the inertial profiler is a single device that can reproduce the results of many devices. The high speed inertial profiler was first developed by General Motors in the 1960s and was adopted by the pavement industry for research purposes. Inertial profilers are also used by many state roadway departments for data collection at high speeds on highways.

The inertial profiler consists of three sensors: a laser, a speed sensor, and an accelerometer. The sensors are mounted to the side of a vehicle in its wheel path. The setup can be mounted on most vehicles and still produce accurate results, but is most commonly used on the NDT Van. The laser sensor points downwards and measures vertical distance to the pavement. The speed sensor records the vehicle’s speed and determines the horizontal distance traveled. The accelerometer measures vertical acceleration of the vehicle, which can be double integrated to determine the vertical distance traveled. A test begins while stopped, then the driver accelerates quickly to a certain speed and holds that speed while recording data. The driver’s ability to drive straight and maintain a proper speed plays a large role in ensuring quality data. The presented accelerometer is single-axis, but multi-axis accelerometers can also be used. Adding an optional GPS provides related coordinate data. Specialized computer software is used to collect and analyze the data from all of the sensors.

The main advantage of the inertial profiler is its speed, as it travels many times faster than other roughness measuring devices. For longitudinal field testing, this allows huge time savings, especially on long airfields. An important feature of the inertial profiler is its mobility, as it can be driven to test sites easily. If necessary, the system can be removed from the NDT Van and transported alone.

Inertial Profiler Equipment Diagram (Click to Zoom)

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