SDR-Based Dual Polarized L-Band Microwave Radiometer Operating From Small UAS Platforms

Md Mehedi Farhad; Ahmed Manavi Alam; Sabyasachi Biswas; Mohammad Abdus Shahid Rafi; Ali C. Gurbuz; Mehmet Kurum

doi:10.1109/JSTARS.2024.3394054

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing (Jan 2024)

SDR-Based Dual Polarized L-Band Microwave Radiometer Operating From Small UAS Platforms

Md Mehedi Farhad,
Ahmed Manavi Alam,
Sabyasachi Biswas,
Mohammad Abdus Shahid Rafi,
Ali C. Gurbuz,
Mehmet Kurum

Affiliations

Md Mehedi Farhad: ORCiD; Department of Electrical and Computer Engineering, and Information Processing and Sensing Lab, Mississippi State University, Mississippi State, MS, USA
Ahmed Manavi Alam: ORCiD; Department of Electrical and Computer Engineering, and Information Processing and Sensing Lab, Mississippi State University, Mississippi State, MS, USA
Sabyasachi Biswas: ORCiD; Department of Electrical and Computer Engineering, and Information Processing and Sensing Lab, Mississippi State University, Mississippi State, MS, USA
Mohammad Abdus Shahid Rafi: ORCiD; Department of Electrical and Computer Engineering, and Information Processing and Sensing Lab, Mississippi State University, Mississippi State, MS, USA
Ali C. Gurbuz: ORCiD; Department of Electrical and Computer Engineering, and Information Processing and Sensing Lab, Mississippi State University, Mississippi State, MS, USA
Mehmet Kurum: ORCiD; School of Electrical and Computer Engineering, the University of Georgia, Athens, GA, USA

DOI: https://doi.org/10.1109/JSTARS.2024.3394054
Journal volume & issue: Vol. 17
pp. 9389 – 9402

Abstract

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Passive microwave remote sensing is a vital tool for acquiring valuable information regarding the Earth's surface, with significant applications in agriculture, water management, forestry, and various environmental disciplines. Precision agricultural (PA) practices necessitate the availability of field-scale, high-resolution remote sensing data products. This study focuses on the design and development of a cost-effective, portable L-band microwave radiometer capable of operating from an unmanned aircraft system platform to measure high-resolution surface brightness temperature ($T_{B}$). This radiometer consists of a dual-polarized (Horizontal polarized, H-pol and Vertical polarized, V-pol) antenna and a software-defined radio-based receiver system with a 30 MHz sampling rate. The post-processing methodology encompasses the conversion of raw in-phase and quadratic (I&Q) surface emissions to radiation $T_{B}$ through internal and external calibrations. Radiometric measurements were conducted over an experimental site covering both bare soil within an agricultural field and a large water body. The results yielded a high-resolution $T_{B}$ map that effectively delineated the boundaries between land and water, and identified land surface features. The radiometric temperature measurements of the sky and blackbody demonstrated a standard deviation of 0.95 K for H-pol and 0.57 K for V-pol in the case of the sky and 0.39 K for both H-pol and V-pol in the case of the blackbody observations. The utilization of I&Q samples acquired via the radiometer digital back-end facilitates the generation of different time–frequency (TF) analyses through short-time Fourier transform and power spectral density (PSD). The transformation of radiometer samples into TF representations aids in the identification and mitigation of radio frequency interference originating from the instrument itself and external sources.

Published in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

ISSN: 1939-1404 (Print); 2151-1535 (Online)
Publisher: IEEE
Country of publisher: United States
LCC subjects: Technology: Ocean engineering; Science: Physics: Geophysics. Cosmic physics
Website: https://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=4609443

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