Abstract: The baseline length is the basis of interferometric synthetic aperture radar (InSAR).The study of the relationship between baseline and coherence has important reference value for the choice of interference image pairs.A combination of theoretical analysis and simulation experiment is adopted.The influence of temporal and spatial baselines on coherence is analyzed theoretically,and the model relationship between spatio-temporal baseline and coherence is established by simulation experiment.And 16 groups of data selected randomly are used to validate the model.The results show that the time baseline and the spatial baseline have inverse power function relation with the coherence respectively,and the spatio-temporal baseline model established in this paper is very close to the software module,the correlation coefficient is as high as 0.92,which shows that the model in this paper is reasonable,and it can be used as reference for selection of interference image.

Key words: spatio-temporal baseline, coherence, decorrelation, interferometry