Level-1 Calibration Assessment of Spire's LEMUR-2 GNSS-R Ocean Normalized Bistatic Radar Cross Section Estimates

• Published in: IEEE geoscience and remote sensing letters Vol. 20; pp. 1 - 5
• Main Authors: Al-Khaldi, Mohammad M., Gleason, Scott, Linnabary, Ryan, Policelli, Frederick S.
• Format: Journal Article
• Language: English
• Published: Goddard Space Flight Center IEEE 01-01-2023; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bistatic radar systems; Calibration; CubeSats; Earth Resources and Remote Sensing; Global navigation satellite system; Global Navigation Satellite Systems Reflectometry (GNSS-R); Global Positioning System; Multistatic radar; Navigation; Navigation satellites; Navigation systems; Navigational satellites; Ocean surface; Oceans; Radar; Radar cross sections; rough surface scattering; Satellite observation; Sea measurements; Sea surface; SmallSats; Surface wind; Transmitters; Weather forecasting; Wind; Wind speed
• ISSN: 1545-598X; 1558-0571
• DOI: 10.1109/LGRS.2023.3249405

An assessment of the ocean surface Level-1 normalized bistatic radar cross Section (BRCS) products provided by the two batch 1 "LEMUR-2" Global Navigation Satellite Systems Reflectometry (GNSS-R) receivers of Spire, Inc. is reported. The analysis uses datasets extending from DOY 345, 2020 to DOY 329, 2021. Initial assessments indicate a highly consistent overall interchannel response with mean normalized bistatic radar cross Section (NBRCS) differences estimated to be at the 1.00% level over a 7-12-m/s European Centre for Medium-Range Weather Forecasts (ECMWF) reference wind speed range. Efforts to validate the observation systems' aggregate response relative to <inline-formula> <tex-math notation="LaTeX">\approx 3 </tex-math></inline-formula> million colocated Cyclone Global Navigation Satellite System (CYGNSS) measurements suggest a highly complementary behavior with an overall NBRCS correlation of 79.03% highlighting the potential utility of "LEMUR-2" measurements for ocean surface wind sensing and related applications. Nonphysical NBRCS dependencies on various Level-1 calibration variables, also observed with GNSS-R previous systems, are nonetheless noted and are explored in detail.