Azimuth High Resolution for a Conically Scanned Pencil-Beam Scatterometer Using Rotating Azimuth Doppler Discrimination

In order to satisfy a relatively high resolution for the retrieval of snow water equivalent, an X/Ku-band dual-frequency full-polarized SCATterometer (DFPSCAT) onboard Water Cycle Observation Mission (WCOM) satellite is designed for high-resolution observations. However, given the following situations, the method called “rotating azimuth Doppler discrimination” is proposed, which can satisfy the resolution requirement and real-time processing: 1) the conically rotation rate of antenna is relatively fast; 2) the swath width is larger than 1000 km; and 3) day or night observation capabilities are required. Considering the complexity of the system's design and the improvement of azimuth resolution capability, a burst pulsing scheme is addressed to satisfy the numbers of azimuth sampling. The simulation model is used to analyze the feasibility of azimuth discrimination method based on geometry and system parameters. It is shown that the achievable azimuth resolution is about 2-5 km at far end of the swath and only 5km at near end of the swath. The results show that when the size of a slice is set as 2-5 km, the Kpc is about less than 0.4 as snow depth varies, and the Kpc of combined slices is smaller than a single slice.