Issues related to waveform computations for radar altimeter applications

An algorithm has been developed to model the average return power waveforms available from general radar altimeter systems. The algorithm is based on a convolutional model comprising three functions: the average flat surface impulse response (FSIR), the radar system point target response (PTR), and the height PDF of the specular points on the sea surface. The FSIR is modified to account for the asymmetric antenna beam used by the MARA system, and then certain properties of this modified FSIR are exploited to obtain closed-form expressions that can be rapidly evaluated. A fast Fourier transform (FFT) convolution routine is used to further speed up the computations. The result is an algorithm that can be used to study the effects of pointing errors in surface measurements. >