Inter-satellite laser ranging is a key technology to improve the measurement precision of gravity satellites in future missions. However, it requires a stable laser link between satellites, which would be affected by external disturbances in space and internal couplings of satellite components. This paper presents a dynamic model to describe the tracking error and proposes a high-precision satellite simulator for the validation of inter-satellite laser tracking. Then, the noises of the sensors and actuators are tested to give the theoretical tracking performance of the simulator. Finally, the laser tracking performance is validated through two experiments: fixed-position tracking and motion tracking. The experimental results show that the measured tracking error of the satellite platform is better than 10 mrad/Hz in the fixed-position tracking and 50 mrad/Hz in the motion tracking. Furthermore, the optical platform can reduce the measured tracking error to 80 μrad/Hz in both two experiments. This work provides a theoretical foundation for optimizing laser tracking performance in space missions, and the proposed simulator has demonstrated a potential for mission simulation with laser tracking.
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Sci Rep
December 2024
Computing for Sustainability and Social Good (C2SG) Research Group, United International University, Dhaka, Bangladesh.
In the twenty-first century, maritime routes are crucial for geographical and financial reasons in riverine countries. Compared to the available technology abroad, Bangladesh has insufficient monitoring of water vessels to tackle any possible disaster, such as vessel collisions for inland water transportation. One of the frequent outcomes of this architecture is regular capsizing, which sometimes leads to loss of lives.
View Article and Find Full Text PDFBiosensors (Basel)
December 2024
Guangdong Laboratory of Artificial Intelligence and Digital Economy (SZ), Shenzhen 518107, China.
The demand for non-invasive, real-time health monitoring has driven advancements in wearable sensors for tracking biomarkers in sweat. Ammonium ions (NH) in sweat serve as indicators of metabolic function, muscle fatigue, and kidney health. Although current ion-selective all-solid-state printed sensors based on nanocomposites typically exhibit good sensitivity (~50 mV/log [NH]), low detection limits (LOD ranging from 10 to 10 M), and wide linearity ranges (from 10 to 10 M), few have reported the stability test results necessary for their integration into commercial products for future practical applications.
View Article and Find Full Text PDFMol Plant
December 2024
Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, MOE Key Laboratory & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China. Electronic address:
In eukaryotic cells, autophagosomes are double-membrane vesicles that are highly mobile and traffic along cytoskeletal tracks. While core autophagy-related proteins (ATGs) and other regulators involved in autophagosome biogenesis in plants have been extensively studied, the specific components regulating plant autophagosome motility remain elusive. In this study, using TurboID-based proximity labelling, we identify the retromer subcomplex comprising sorting nexin 1 (SNX1), SNX2a, and SNX2b as interacting partners of ATG8.
View Article and Find Full Text PDFPhotoacoustics
February 2025
Dipartimento di Scienze di Base ed Applicate per l'Ingegneria, Sapienza Università di Roma, Rome 00161, Italy.
A compact and robust optical excitation photoacoustic sensor with a self-integrated laser module excitation and an optimized differential resonator was developed to achieve high sensitivity and full linear range detection of carbon dioxide (CO) based on dual modes of wavelength modulated photoacoustic spectroscopy (WMPAS) and resonant frequency tracking (RFT). The integrated laser module equipped with three lasers (a quantum cascade laser (QCL), a distributed feedback laser (DFB) and a He-Ne laser) working in a time-division multiplexing mode was used as an integrated set of spectroscopic sources for detection of the designated concentration levels of CO. With the absorption photoacoustic mode, the WMPAS detection with the QCL and DFB sources was capable of CO detection at concentrations below 20 %, yielding a noise equivalent concentration (NEC) as low as 240 ppt and a normalized noise equivalent absorption coefficient (NNEA) of 4.
View Article and Find Full Text PDFACS Photonics
December 2024
School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, U.K.
Tightly confined plasmons in metal nanogaps are highly sensitive to surface inhomogeneities and defects due to the nanoscale optical confinement, but tracking and monitoring their location is hard. Here, we probe a 1-D extended nanocavity using a plasmonic silver nanowire (AgNW) on mirror geometry. Morphological changes inside the nanocavity are induced locally using optical excitation and probed locally through simultaneous measurements of surface enhanced Raman scattering (SERS) and dark-field spectroscopy.
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