Slant range and 3D sea floor models for real-time UUV simulation

Slant range and 3-D sea floor models were used in a real-time unmanned underwater vehicle (UUV) simulation with a 3-D display. Two methods were used to generate 3-D terrain models. The first method uses specified spectral characteristics, random variations, and a discrete Fourier transform to generate plausible terrain. The second method uses non-Cartesian interpolation to convert contour information from oceanographic maps to a regular grid. Using terrain generated by either method, sensor models call a slant range algorithm to calculate, in real-time, the distance along the sensor beam to the first intersection of that beam with the terrain