are equal or linearly proportional to each other, otherwise causing rank deficiency. Compared with the multitrack/multisensor method, the InSAR+model method can effectively relax the requirement for SAR data sets, i.e., only a single InSAR pair for the latter method, but at least three for the former method. Hence, the InSAR+model method is more readily performed in practice than is the multitrack/multisensor method. Furthermore, the assistance of a deformation model can effectively improve the accuracy of the movement estimates (m) 16 Aug. 2007 1 Oct. 2007 1 Jan. 2008 2 Apr. 2008 16 May 2008 0.1 16 Feb. 2008 0 Vertical Advancing Direction 0.05 300 600 900 m (m) 16 Aug. 2007 1 Oct. 2007 0 1 Jan. 2008 0.3 16 Feb. 2008 2 Apr. 2008 East 0.15 0 16 May 2008 -0.15 0 300 600 900 m -0.3 (m) 16 Aug. 2007 1 Oct. 2007 1 Jan. 2008 0.11 0.06 16 Feb. 2008 2 Apr. 2008 16 May 2008 North 0.01 -0.04 -0.09 0 300 600 900 m -0.14 FIGURE 3. A TS 3D mining displacement in the Datong coal mining area of China between 16 August 2007 and 16 May 2008, generated from ascending ALOS PALSAR images using the prior model of (8) [98]. 78 IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE MARCH 2020