Matched filtering-based estimation of ground elevation using laser altimetry

The authors present a method for determining the time-of-arrival (TOA) of the ground component of a laser altimetry return signal. The proposed method takes advantage of the fact that the ground component or ground return is approximately Gaussian shaped and occurs at the end of the return signal. In particular, the method exploits the well-known result that the TOA of a known signal in white Gaussian noise can be estimated using matched filtering. An important feature of the method is that it addresses the problem of overlap between ground and vegetation returns. Simulations using synthetic data indicate that the proposed method provides excellent estimates and greatly outperforms a conventional method. It is anticipated that the method will be applicable to laser altimetry applications where the ground return can be assumed to have an approximately known shape.