Measurement of Ocean Wave Heights with the Random-Signal Radar

When a radar antenna is pointed directly down at the sea surface, the return signal is caused mainly by specular points on the surface. In this case, the sea surface can be modeled as a collection of Poisson-distributed point scatterers, each having a certain radar range and a certain vertical velocity. This model can be characterized by a deterministic function, called the scatterer density function, which is the density of specular point scatterers in the two-dimensional range-velocity space. This function can be estimated by using a high-resolution random-signal radar and provides information relating the dynamic aspects of the ocean surface to the distribution of wave heights. A special case of this problem is the estimation of average wave height, or sea state, and a specific technique to estimate this quantity is proposed and analyzed. This technique has the advantage of being a direct estimation procedure; i.e., the quantity measured is wave height, not a quantity that has been empirically related to wave height.