A method for characterizing three-dimensional spatial channels for high speed railroad scenarios

When the receiving platform moves in a straight line at constant velocity, as in the case of high-speed rail, the scenario begins to resemble that of a bistatic synthetic aperture radar (BiSAR). Because we can predict the range-Doppler history of the returns from each scatterer observed over time, we can extract the family of returns from a given scatterer over time and focus them into a single point. In this manner, we can vastly improve both the amplitude and angular resolution of the system. In synthetic aperture radar, the technique is often referred to as Doppler focusing.