Shallow Angle Wave Profiling Lidar

A lidar scanning system is described that is primarily designed to measure sea wave shape. The device is capable of measuring real-time spatial profiles over distances of hundreds of meters, and as the lidar must inevitably operate from modest elevations (e.g., from a vessel’s masthead), it is inherently a very shallow angle metrology device. This results in a highly nonuniform distribution of the wave elevation values. The vertical and horizontal resolution is primarily set by the characteristics of the optical system employed and range/data capacity is set by signal-to-noise ratio considerations. Illustrative data are presented as consecutive profiles taken 0.2 s apart for highly trochoidal waves under conditions where the height was recorded to ±0.03 m and horizontal sample separation to ±0.025 m. A comparison is presented with traditional wave staff measurements.