The New Quad-Pol Characteristics of COSMO-SkyMed Seconda Generazione

As an evolution of the COSMO-SkyMed (CSK) polarimetric capabilities, the COSMO-SkyMed Seconda Generazione (CSG) SAR payload will implement a Dual-pol mode for the main acquisition modalities, transmitting horizontal (H) or vertical (V) polarization and receiving simultaneously both the H and V components of backscattered echoes. Furthermore, CSG will have a full Quad-pol mode able to estimate the polarimetric characteristics of a target or of an area. In order to acquire the complete scattering matrix (Quad-pol mode), the transmission rate is doubled and the H and V polarizations are used alternatively for the transmission pulse. Both the H and V channels are simultaneously acquired at receiver, thus the four channels (HH, HV, VV, and VH ) can be acquired on the same scene keeping the phase coherence information. In addition, a multi-polarization image can also be acquired using, as CSK, the PINGPONG mode (i.e. “alternating” or “burst polarimetric mode”). The main difference between the two implementation is that in the Quad-pol mode a coherent phase information on the polarimetric channels is acquired, whilst in PING-PONG no phase coherence among the channels is available. This comes at the expenses of the swath width that is more favourable in PING-PONG. The aim of this paper is to describe the architectural implementation of the Quad-pol capability in CSG system, and to analyze the expected incremental benefit in the exploitation of CSG data with respect to CSK data.