Multi-Channel Regression Inversion Method for Passive Remote Sensing of Ice Water Path in the Terahertz Band

Weng, Chensi; Liu, Lei; Gao, Taichang; Hu, Shuai; Li, Shulei; Dou, Fangli; Shang, Jian

doi:10.3390/atmos10080437

Cited by 9 publications

(4 citation statements)

References 23 publications

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“…The terahertz payload incorporates a patch antenna as the receiving element for terahertz signals, taking into account the challenges associated with heterodyne receivers at high frequencies, which often entail increased losses [42,43]. To address this, subharmonic mixers offer a compelling solution, particularly for direct conversion in millimeter-wavelength ranges.…”

Section: Ghz Subharmonic Schottky Diode Spectrometer Designmentioning

confidence: 99%

MeSat Mission: Revolutionizing Mars Exploration with THz Radiometer Payload and Optimal Trajectory

Rastinasab,

Hu,

Saghamanesh

et al. 2023

Preprint

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Space exploration presents vast prospects for scientific, industrial, and economic progress. This paper introduces the MeSat mission as a pioneering approach to Mars exploration. MeSat aims to deepen our understanding of Martian conditions and resources by employing an optimized Earth-to-Mars trajectory, enabling a comprehensive study of the Martian atmosphere and surface. The mission comprises a Cargo Microsatellite hosting three 6U CubeSats and two 3U CubeSats, deployed into four separate Mars orbits forming a constellation. Each CubeSat carries distinct payloads: a THz radiometer for water detection, a high-resolution surface camera, a top-tier spectrometer, and a Fourier Transform Spectrometer (FTS) for wind speed readings. This paper focuses on two pivotal innovations: the development of a 183GHz radiometer payload for detecting water on Mars and a optimal mission design algorithm that analyzes a fuel-efficient low-thrust trajectory from Earth to Mars. Regarding the THz payload for water detection, a subharmonic Schottky diode-based mixer is meticulously designed to efficiently down-convert radio signals. The down-converted signals are carefully analyzed using a customized Do-It-Yourself (DIY) spectrum meter, which facilitated the capture and processing of acquired data. To provide the necessary Local Oscillator signals for the mixer, a Tripler employing three-anode Schottky diodes is developed. Additionally, the Tripler requires a signal generator for its entry frequency, which is addressed by developing a DIY signal generator. Together, these components, comprising the Schottky diode mixer, Tripler, and DIY circuits, collectively form the complete THz payload, demonstrating exceptional power efficiency with a total consumption of only 3.7W. The study employs a dual-step hybrid optimization algorithm (PSO-Homotopy) to analyze fuel-efficient low-thrust trajectories from Earth to Mars, incorporating the Ephemeris dynamics model to account for gravitational perturbations in the entire solar system. In practical mission design, crucial factors like hyperbolic excess velocity, diverse opportunities for Earth launch and Mars rendezvous, varied propulsion systems, and Time of Flight (TOF) play vital roles in trajectory optimization.

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Section: Ghz Subharmonic Schottky Diode Spectrometer Designmentioning

confidence: 99%

MeSat Mission: Revolutionizing Mars Exploration with THz Radiometer Payload and Optimal Trajectory

Rastinasab,

Hu,

Saghamanesh

et al. 2023

Preprint

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“…Inversion methods can be simply divided into the physical method and linear regression method (Weng et al, 2019). The linear regression method is efficient and convenient, but it lacks a definite physical mechanism and is heavily dependent on the accuracy of the pre-calculated database.…”

Section: Introductionmentioning

confidence: 99%

Retrieval of Terahertz Ice Cloud Properties from airborne measurements based on the irregularly shaped Voronoi ice scattering models

Letu

Ishimoto

et al. 2022

Preprint

Self Cite

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Abstract. Currently, the terahertz remote sensing technology is one of the best ways to detect the microphysical properties of ice clouds. Influenced by the representativeness of the ice crystal scattering (ICS) model, the existing terahertz ice cloud remote sensing inversion algorithms still have significant uncertainties. In this study, we developed a terahertz remote sensing inversion algorithm of the ice water path (IWP) and effective particle radius (Re) of ice clouds based on the Voronoi ICS model. This study utilized the single-scattering properties (extinction efficiency, single-scattering albedo and asymmetry factor) of the Voronoi and Sphere ICS models in the terahertz region. Combined with 14,408 groups of particle size distributions obtained from aircraft-based measurements, we completed the Voronoi and Sphere ICS schemes based on the Voronoi and Sphere ICS models. The two schemes were applied to the RSTAR radiative transfer model to carry out the sensitivity analysis of the top of cloud (TOC) terahertz brightness temperature differences (BTDs) on the IWP and Re. The sensitivity results showed that the TOC BTDs between 640 and 874 GHz are functions of the IWP, and the TOC BTDs between 380, 640 and 874 GHz are functions of the Re. The Voronoi ICS scheme possesses stronger sensitivity to the Re than the Sphere ICS scheme. Based on the sensitivity results, we built a multi-channel look-up table for BTDs. The IWP and Re were searched from the look-up table using an optimal estimation algorithm. We used 2000 BTD test data randomly generated by the RSTAR model to assess the algorithm’ s accuracy. Test results showed the correlation coefficients of the retrieved IWP and Re reach 0.99 and 0.98, respectively. As an application, we used the inversion algorithm to retrieve the ice cloud IWP and Re based on the CoSSIR airborne terahertz radiation measurements. Validation against the retrievals of the Bayesian algorithm reveals that the Voronoi ICS model performs better than the Sphere ICS model, with the enhancement of the Mean absolute error of 5.0 % and 12.8 % for IWP and Re, respectively. In summary, the results of this study confirmed the practicality and effectiveness of the Voronoi ICS model in the terahertz remote sensing inversion of ice cloud microphysical properties.

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“…More details are explained in the next sections. In the paper, firstly, we present mission objectives, then continue on mission scenario, and at the end, we present the satellite project system with a THz radiometer for detecting ice water on the Moon for creating the next generation of deep space exploration by using small satellites [17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Water Recognition on the Moon by Using THz Heterodyne-Spectrometer for Identifying the Appropriate Locations to Extract Water for Providing Oxygen for Breathing and Fuel for Spaceships’ Propulsion on the Moon with CubeSat

Rastinasab

Tahmasebi

2021

Aerospace

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Asteroid mining offers vital sources for improving human lives and provides opportunities for interplanetary missions and space travel. There are many professional commercial space companies that are only investing billions of dollars on asteroids mining, but prior to that, one condition for asteroid mining could be planetary stations to refuel the pioneers’ spacecraft or human colonies on alien planets; hence, one of the vital sources for these purposes is water. Water can be harvested to split oxygen for breathing and hydrogen for refueling spaceships’ propulsions, and Earth-to-space water payload transporting is extremely expensive; therefore, discovering extraterrestrial water in outer space is economically beneficial. This paper presents a Lunar CubeSat Injector to deliver four 3U CubeSats into Low Lunar Orbit to make a constellation to identify locations of water sources on the Moon by using a THz heterodyne-spectrometer. In sum, this project can help scientists to recognize more water resources for those who will colonize the Moon and for those planning to go beyond it.

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Multi-Channel Regression Inversion Method for Passive Remote Sensing of Ice Water Path in the Terahertz Band

Cited by 9 publications

References 23 publications

MeSat Mission: Revolutionizing Mars Exploration with THz Radiometer Payload and Optimal Trajectory

MeSat Mission: Revolutionizing Mars Exploration with THz Radiometer Payload and Optimal Trajectory

Retrieval of Terahertz Ice Cloud Properties from airborne measurements based on the irregularly shaped Voronoi ice scattering models

Water Recognition on the Moon by Using THz Heterodyne-Spectrometer for Identifying the Appropriate Locations to Extract Water for Providing Oxygen for Breathing and Fuel for Spaceships’ Propulsion on the Moon with CubeSat

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