Bistatic Signal Penetration Geometry over Land Ice for the Harmony Mission

Abstract

To derive elevation models and topographic change of glaciers and ice sheets, the Harmony mission's across-track InSAR phase requires accurate elevation bias correction due to signal penetration into dry snow, firn, and ice. This paper extends a monostatic penetration bias model to the bistatic geometry, incorporating the effect of the large squint angle between transmitter and receiver. The calculations show only a few percent difference in 2-way penetration depth between the bistatic Harmony geometry and conventional monostatic InSAR for identical signal extinction and penetration length. The derived bistatic volume decorrelation model establishes the relationship between coherence, phase, and penetration depth. This allows a penetration bias correction of individual Harmony interferograms, assuming constant, isotropic signal extinction, as already established for monostatic InSAR.