Multiangle Asymmetric Coplanar Analysis for 3-D Wind Retrieval Using HAPS-Borne Phased Array Weather Radar

The emerging high-altitude platform station (HAPS, such as the near-space airship) is located in the stratosphere at a height around 20 km and has great potential in remote sensing due to its insensitivity to severe weather conditions and the advantage of long dwell time over observation area of interest. Traditionally, airborne Doppler radars employ fixed-angle symmetric coplanar analysis technique (FA-SCAT) for 3-D wind field (3D-WF) retrieval in severe weather. However, FA-SCAT fails in HAPS-borne weather radar due to its low velocity (usually <15 m/s) and subsequently low spatial coverage. In this letter, a novel multiangle asymmetric coplanar analysis technique (MA-ASCAT) for 3D-WF retrieval applied to HAPS-borne phased array radar is proposed. It utilizes multiple observations of the same target bin to retrieve 3D-WF based on the multiple-angle data collected by multiple HAPSs at multiple observation positions. The MA-ASCAT performance is deduced theoretically, which is used to optimize the systematic scanning strategy. The method is validated through simulation and real data experiments. Results demonstrate that MA-ASCAT achieves superior detection coverage and accuracy compared to FA-SCAT.