Along-track baseline in DS-SAR causes different squint angles of master satellite and slave satellite, which leads to different Doppler centroid frequencies.
Besides coupling problem, there is dynamic variation of DS-SAR baseline in along-track direction during the whole data-take time.
Figure 3 shows the flowchart of dynamic and coupling baseline estimation of DS-SAR.
a) Getting SLC SAR data pair using DS-SAR imaging algorithm.
The estimation accuracy of traditional interferometric fringe frequency estimation method, based on Fourier transform, cannot satisfy the DS-SAR system perfectly.
By modelling the satellite-ground geometry of DS-SAR, SLC images of master and slave satellite SAR are simulated.