Identification of Nearshore Wave Characteristics Using Robotic Total Stations

Abstract

A new geodetic method for accurate determination of nearshore wave characteristics is proposed. This method is based on a robotic total station set on stable position on the coast and aiming at a passive reflector mounted on a buoy, usually at a distance of a few hundred meters. This method permits the identification of the changing three-dimensional coordinates of the reflector/buoy in a selected, fixed coordinate system independent of the buoy with centimeter accuracy, and a rate of up to 6 Hz, and it can even determine very precisely waveforms, including those with steep sides. The effectiveness of the method is demonstrated on the basis of results of two cases studies. While this method provides exceptional quality results for small waves, it can also be used for large waves as well, and especially to calibrate other wave measurement techniques. Techniques to avoid clipping effects usually affecting the wave measurements and the possibility to measure the wave and current direction are also discussed.