Patent ID: 7748264

Claim:
A method for measuring the unevenness of a pavement surface comprising: (i) transporting in a given direction above the pavement surface a sensor support frame carrying an array of sensors, said array having a plurality of sensors spaced by set distances and aligned in said given direction; (ii) at a first position of said frame, measuring with each of said sensors and recording a parameter indicative of the distance of each said sensor from respective first points in a first array of points on the pavement surface; (iii) while moving the sensor support frame in said given direction from the first position, measuring at a plurality of positions of said frame the parameter indicative of the distance of each said sensor from respective subsequent points on the pavement surface; (iv) determining a second position of the frame when a plurality of the sensors in said array are measuring the parameter from respective second points in a second array of points, said second array of points being displaced from said first array of points by a distance equal to a said set distance between adjacent said first points and in the direction of transportation, and recording for the sensors the parameter measurements at said second position of the frame; (v) calculating from said measurements at the second position, any change in tilt of the frame between the first and second positions; (vi) repeating steps (iii) to (v) allowing for said change in tilt when linking measurements to produce a continuous profile over multiple said positions of the frame; (vii) repeating the transportation, measurement and calculation steps progressively along the pavement surface to generate a sequence of profiles each with a known relative position and alignment; and (viii) generating from said sequence of profiles known relative positions and alignments, an indication of the unevenness of the surface.