Distributed Precipitation Radar Constellation: Formation Flying Strategies for Large Aperture Synthesis

Abstract

This paper presents an overview of precipitation measuring missions previously conducted by Japan Aerospace Exploration Agency (JAXA), including the Tropical Rainfall Measuring Mission (TRMM), the Global Precipitation Measurement (GPM) mission, and the upcoming Precipitation Measuring Mission (PMM), which is scheduled for launch after Japan’s FY2028. These missions have contributed significantly to global precipitation monitoring using spaceborne radar systems. In anticipation of future scientific needs, this study investigates one of the concepts for a new precipitation measuring system based on a constellation of small satellites. The proposed architecture employs distributed radar techniques with formation flying, aiming to achieve high-resolution cross-track measurements through a synthesized large antenna aperture. We provide strategies of orbital design and station keeping, and present the results of detailed orbital analyses, including the effects of non-conservative perturbations, to evaluate the feasibility of the proposed configurations. Technical challenges related to the implementation of the proposed system for precipitation monitoring are also discussed.