Efficient Three-Dimensional Imaging Method Based on Enhanced Range Point Migration for UWB Radars

Ultrawideband pulse radar has a definite advantage over optical ranging techniques in harsh optical environments, such as a dark smog or strong backlight. In security or rescue situations with blurry visibility, it is particularly promising for identifying human bodies. One of the most promising approaches for this type of application is the recently proposed range point migration (RPM) method, which is beneficial for nonparametric imaging and is robust in noisy or heavy interference situations. However, the original RPM requires a discretization of the direction-of-arrival variables in its search operation. The resulting coarse discretization seriously degrades the imaging accuracy, particularly for 3-D problems and far-field observations. Consequently, in this approach, there is a major tradeoff between the amount of computation and accuracy. To overcome this difficulty, this letter proposes a more efficient RPM method, where the extraction of the point of intersection of spheres is adopted. A distinct advantage of this method is that the accuracy is basically invariant to the observation range when avoiding the aforementioned discretization. Numerical simulations including noisy cases prove that our proposed RPM significantly reduces the computation complexity while retaining imaging accuracy.