Interferometric ISAR elevation measurement algorithm for round-loop antenna

The interferometric inverse synthetic aperture radar (ISAR) imaging algorithm for round-loop of two radar antennas in a plane is proposed. The interferometric ISAR imaging algorithm ignores the antenna geometry effect and assumes radar antennae as two vertical antennas with a difference in an altitude direction. Based on it, this paper deduces an interferometric ISAR elevation measurement algorithm when the two antennas are out of the vertical, especially in a round-loop plane. Results show that in this case, the elevation measurement is related with the baseline length and the cross-range of the scattering point. Thus, before the interferometric process, the cross-range estimation is made. Simulation results verify that the interferometric ISAR elevation measurement algorithm is correct. The effect of the angle variation between the real baseline and the valid baseline on the elevation measure accuracy is analyzed. By statistic, the average measure error of the target elevation is less than 3% and it is almost achieve the accuracy of two original vertical ones.