. 24/7 Space News .
Ocean lidar remote sensing technology based on Brillouin scattering spectrum
by Staff Writers
Wuhan, China (SPX) Sep 12, 2022

Schematic diagram of Brillouin underwater lidar experimental system for temperature and salinity measurement based on multi-edge technology.

The monitoring of marine environmental information is of great significance to the development of marine science, the maintenance of marine rights and interests, the development of marine resources and the establishment of marine industry. Laser remote sensing has become one of the important means of marine environmental monitoring because of its advantages of penetrating water, strong energy and high vertical profile resolution.

Ocean laser remote sensing mainly measures environmental information by analyzing the backscattered echo energy or the spectral information. In the energy dimension, the backscattered echo contains a variety of scattered signals and noise, and the echo signal-to-noise ratio is low, which limits the measurement accuracy. Besides, the characteristic information of echo energy is limited which is just used for single parameter inversion.

While different scatterings have their own spectral distribution characteristics in the spectral dimension, and the spectrum is not easy to be contaminated by noise, leading to high signal-to-noise ratio. At the same time, the spectrum contains rich information, and the measurement of multiple environmental elements can be realized through a variety of spectral features. Therefore, lidar using spectral detection is an important direction for the development of marine monitoring in the future.

Compared with other scattering spectra, Brillouin scattering spectrum can be distinguished independently, and the spectrum is stable and has rich information. The simultaneous inversion of seawater temperature and salinity can be realized by Brillouin spectrum.

In addition, the Brillouin scattering cross section is large making Brillouin detection with strong scattering signal and detection depth. Therefore, lidar based on Brillouin spectrum measurement has great potential in marine multi-parameter remote sensing.

At present, Brillouin lidar has fully proved its ability in high-precision measurement of seawater temperature and salinity vertical profile in theory, simulation and laboratory experiments.

However, the existing Brillouin spectral measurement technology has the application requirements of real-time, spectral detection integrity, and fast and continuous measurement in the application of real-time synchronous measurement of seawater subsurface temperature and salinity vertical profile. Therefore, breaking through the technical bottleneck of real-time and continuous measurement of complete Brillouin scattering spectrum is an important research topic to promote the application of Brillouin lidar.

According to the actual measurement needs of Brillouin lidar, the research group of Prof. Kun Liang from Huazhong University of Science and Technology, together with Beijing Space Electromechanical Research Institute and University of Electronic Science and Technology, carried out the research work of using Brillouin spectrum to realize high-precision profile measurement of underwater temperature and salinity.

The team proposed the Brillouin spectrum measurement method of double edge combined with PMT. Based on the idea of sparse reconstruction, the energies of two or more local narrow-band spectra are measured by multi-edge filter. Then, with the help of the function of Brillouin scattering spectrum, the complete Brillouin scattering spectrum with ultra-high resolution is obtained by using the energies. Finally, the spectral characteristic parameters of the scattering spectrum are extracted and used for synchronous inversion of seawater temperature and salinity.

The measurement technique adopts a wide-band multi-channel edge filter to ensure that each channel can transmit large spectral energy, which theoretically ensures the bathymetric ability of the system. The complete super-resolution spectrum is reconstructed according to the sparse low-resolution narrow-band filter, and the high-precision measurement of Brillouin spectrum is realized. Therefore, this technique considers the detection depth and measurement accuracy of the system.

In addition, the photoelectric conversion module with high sensitivity and short response time, and high sampling rate data acquisition module are also used in the system to ensure the rapid continuous profile measurement of seawater temperature and salinity.

According to the principle of Brillouin detection technology, the team developed a lidar test system. This system adopts a transceiver coaxial design, and the laser is incident into the water through the telescope system to generate Brillouin scattering signal. The backscattered signal received by the telescope system is firstly get through the iodine pool to filter the Rayleigh scattering and meter scattering background noise.

Then, the remaining Brillouin scattering light is divided into two parts. One part is collected by PMT as the reference signal (signal Ig), and the other part after the double edge filter composed of two Fabry Perot etalon is collected by two PMTs (signals I1 and I2). Finally, based on the obtained two relative edge energies I1 / Ig and I2 / Ig, the corresponding Brillouin scattering spectra are obtained with idea of sparse reconstruction.

After obtaining the spectrum by using the above system, with the operations of data feature analysis, spectral feature extraction data correction and temperature and salinity inversion model, the system realizes the measurement with temperature accuracy of 0.5 ? and salinity accuracy of 1psu, which has reached the highest level in the world.

All in all, the measurement results show the potential of Brillouin spectrum detection method in seawater environmental element measurement and oceanographic research and provide theoretical and technical support for promoting the practical application of lidar based on Brillouin scattering.

Research Report:Brillouin scattering spectrum for liquid detection and applications in oceanography

Related Links
Huazhong University of Science and Technology
Space Technology News - Applications and Research

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only
SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Raytheon to upgrade Australian border surveillance aircraft with advanced radar
Adelaide, Australia (SPX) Jul 28, 2022
Raytheon Intelligence and Space, a Raytheon Technologies business, will equip Australian border surveillance aircraft with its latest SeaVue Multi-Role radar under a contract with Cobham Special Mission. Under the contract, RI&S will upgrade Cobham's fleet of Dash 8 fixed-wing aircraft to the most advanced version of its SeaVue multi-domain surveillance radar in support of Australian border protection operations. SeaVue MR will bring long-range, high-altitude surveillance capabilities to the ... read more

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Space seeds thrive at the United Nations Campus

Redwire and Sodern team up to market the Exquisite-Class Eagle Eye Star Tracker

US should end ISS collaboration with Russia

Harris talks with space station astronauts, introduces new initiatives

Rocket Lab Prepares to Launch Synspective Satellite on 30th Electron Launch

SpaceX launches 34 more Starlink satellites, AST SpaceMobile satellite

Uncrewed Blue Origin rocket crashes in setback for space tourism

Blue Origin rocket suffers booster failure, prompting emergency abort system

Searching for Frost at Jezero Crater

Sols 3592-3593: Onwards

Glaciers flowed on ancient Mars, but slowly

Martian rock-metal composite shows potential of 3D printing on Mars

Rocket to carry Mengtian space lab module arrives at launch site

Duo undertake 7-hour spacewalk

Chinese scientist advocates int'l cooperation in space science

China's Shenzhou-14 astronauts carry out spacewalk

Spaceflight signs with NewSpace India to launch Astrocast IoT satellite into orbit

OneWeb and HD Hyundai Avikus to advance marine technology by unlocking the potential of LEO connectivity

MDA Selected by Airbus OneWeb Satellites for US Government Program

PCX Aerosystems Announces Acquisition of NuSpace

Ocean lidar remote sensing technology based on Brillouin scattering spectrum

Crisis-hit German toilet paper maker turns to coffee grounds

How the tide turned on data centres in Europe

Vestigo Aerospace raises $375K in seed funding to spur deorbit systems

Twisted magnetic fields can reveal how protobinary systems, Tatooine planets form

A thousand days of CHEOPS

Surprise finding suggests 'water worlds' are more common than we thought

Two new rocky worlds around an ultra-cool star

NASA's Juno Mission Reveals Jupiter's Complex Colors

The PI's Perspective: Extending Exploration and Making Distant Discoveries

Uranus to begin reversing path across the night sky on Wednesday

Underwater snow gives clues about Europa's icy shell

The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.