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Abstract
A moving target parameter estimation algorithm based on the fractional Fourier transform (FrFT) in combination with along-track interferometry (ATI) was developed previously for airborne (or flat Earth) geometry. Subtle differences exist in migrating from a flat stationary Earth geometry to a spherical rotating Earth geometry. Factors, such as orbital parameters and spacecraft centripetal acceleration, must be taken into account. In addition, the dynamic antenna squint implemented in the RADARSAT-2 satellite for Earth motion compensation needs to be modelled into the algorithm. This paper derives the spaceborne version (i.e. RADARSAT-2) of the algorithm. A simple two-dimensional (2D) signal model is derived and compared to that of three-dimensional (3D) spherical model to warrant its usage, and the FrFT-ATI algorithm is implemented using the derived 2D signal model. Its effectiveness is demonstrated using simulation data.