Experimental demonstration for the attitude measurement capability of interferometric radar altimeter

In this paper we will show that by using the nadir interferometric two beams, the obtained interferometric phase (InPha) can help us to estimate the baseline status. The basic idea is that the InPha is related to actual observation geometry, i.e. the baseline status, height of platform, incidence angles as well as the topography of the target. If we can rule out the possibility of height variation of platform or the target, then we can relate the phase variation to the baseline status (rolling angle and baseline length). An airborne interferometric altimetry experiment over lake with multi-carrier frequencies was carried out to test this idea and promising results were obtained. The retrieved roll angles from the InPhas of all three carrier frequencies agree with that from onboard GPS based INS measurement. Analysis on the following equation (3) shows that the measurement accuracy of roll angle from Inphas can be as high as 0.00043°.