Shape sensing techniques enable the real-time reconstruction of wing displacements based on measured strain. As wing designs become more flexible, they may at some point exhibit geometric non-linear deformation. This eventually leads to erroneous displacement estimates if applied methods rely on the assumption of linear deformation. In this research, the Incremental Modal Method (IMM) is presented which accounts for the change of the employed mode shapes due to structural deformation. The method is applied on the finite element model of a high aspect ratio wing undergoing geometric non-linear deflections in flap-wise bending. In the process, a setup of virtual strain sensors is presumed which is representative as instrumentation in experiments. Along a reference line of the wing, the displacement estimates of IMM are compared to results obtained using the Modal Rotation Method (MRM), another shape sensing scheme recently developed for the non-linear regime. For the chosen segmentation and virtual instrumentation of the investigated wing, IMM proves to be a promising candidate for realtime displacement reconstruction in experiments, provided that mode shapes in intermediate deflected states can be determined. @en