{"title":"Forward model for O2 A-band night glow limb radiance in the mesophere and lower thermosphere","authors":"Weijia Wang, Haiyan Luo, Zhiwei Li, W. Xiong","doi":"10.1117/12.2682207","DOIUrl":"https://doi.org/10.1117/12.2682207","url":null,"abstract":"The temperature structure of the global mesosphere and lower atmosphere (MLT) is significant for the study of atmospheric physical, chemical and kinetic processes. Oxygen (O2) A-band airglow (762 nm) can be used as an important tracer to detect the atmospheric temperature structure. The advantage of spatial heterodyne spectrometer (SHS) is high stability, high throughput and high spectral resolution. The fine spectral structure of A-band night glow is detected by limb observation combined with simultaneous split field imaging of atmospheric vertical profile, and the temperature information is retrieved by recovering spectra. Building an accurate forward model is the premise and foundation to obtain the global spaceborne high-resolution atmospheric temperature structure. Based on the A-band night glow radiation mechanism, molecular spectroscopy theory, atmospheric radiation transfer theory and the detection principle of SHS, this paper constructs the forward model of target airglow observation. Furthermore, the sensitivity and analysis of the influencing parameters of the forward model is carried out, which provides a theoretical basis fort the forward modes modification and instrument design. The results show that the forward model described in the paper can satisfy the simulation of A-band night glow spectral radiance observed by SHS at any location through limb observation combined with simultaneous split field of atmospheric vertical profile. That is, the atmospheric tangent range covers 80-120 km and the vertical resolution is better than 2 km. It lays a foundation for the space-borne SHS to detect and accurately retrieve the global temperature structure in MLT region.","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129313151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Coherence analysis of laser pulses based on an external cavity circulation","authors":"He Xu, D. Sun, Jianbing Li","doi":"10.1117/12.2682203","DOIUrl":"https://doi.org/10.1117/12.2682203","url":null,"abstract":"By constructing an external circulating cavity to provide sufficient delay that equals a multiple of pulse repetition time, a method with a fixed experimental configuration is proposed to measure the coherence length of both single-frequency and microwave-modulated optical pulses. This method can accurately determine the number of coherent pulses as well as distinguish the coherence states: complete coherence, partial coherence and complete incoherence. In addition, all desired coherence phenomena are obtained by one-time measurement, avoiding other operations like frequent fiber-cutting or devices-reconnection in previous methods. Simulation results show that the coherence length of the dual-frequency laser is periodically extended by the reciprocal of the frequency difference, and the random jitter of pulse propagation time would result in obvious measurement errors via perturbing coherence status.","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127485968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shunping Chen, Congming Dai, Nana Liu, Wentao Lian, Cong Zhang, F. Wu, Heli Wei
{"title":"MERRA-2 AOD product performance in Eastern and Southern China Sea","authors":"Shunping Chen, Congming Dai, Nana Liu, Wentao Lian, Cong Zhang, F. Wu, Heli Wei","doi":"10.1117/12.2682742","DOIUrl":"https://doi.org/10.1117/12.2682742","url":null,"abstract":"Aerosol optical depth (AOD) is one of the basic parameters used to analyze physical properties of regional aerosols, but the in-situ observation or remote sensing AOD dataset could be scarce especially in ocean area. The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis has the longest temporal span, and its accuracy in China sea area is to be evaluated. This study provides a validation of MERRA-2 AOD products’ applicability in the eastern and southern China sea based on Aerosol Robotic Network (AERONET). The results indicated that the MERRA-2 AOD with 1-hour temporal resolution agreed with the time averaged AERONET AOD well, for its correlation coefficient is 0.887, root mean square error (RMSE) is 0.096, and mean absolute error (MAE) is 0.056. Presented analysis also revealed a systematic underestimation of AOD that MERRA-2 made, and that deviation tended to increase in higher AOD which demonstrated a slope of -0.26 when utilized linear fitting technics, but the mean bias (MB) of test dataset was only -0.001 because the AOD concentrated on lower than 0.2. These results illustrated the suitability of using MERRA-2 AOD product in aerosol researches of the China sea area.","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114252395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhao Ye, Qiang Chen, He Liao, Kehang Li, Chunping Zeng, LiJun Cao, Fang Yang
{"title":"Research on the autonomous avoidance technology of satellite applicable to the low-orbit giant constellations","authors":"Zhao Ye, Qiang Chen, He Liao, Kehang Li, Chunping Zeng, LiJun Cao, Fang Yang","doi":"10.1117/12.2682039","DOIUrl":"https://doi.org/10.1117/12.2682039","url":null,"abstract":"At present, governments around the world and the organization are demonstrating how to deploy LEO communication constellations, such as Starlink, space-based information network and other mega constellations. With the satellite increasing quantity,it greatly increases the risk of satellite in orbit collision. In case of satellite collision early warning, the satellite depends on ground system early warning information, and then guides the satellite to avoid maneuver, the whole chain takes a long time and involves the coordination of multiple departments, multiple personnel and different links. The management cost is very high and the efficiency is low, which cannot meet the needs of orbit collision management of mega constellations .Autonomous avoiding of satellites on orbit is an inevitable trend. In this paper, we devise a scheme for satellite autonomic avoiding on low orbit mega constellations. By analyzing the orbit debris environment of spacecraft, its collision early warning theory is established, the strategies and methods for orbit avoidance are formulated, spacecraft warning software is based on continually update cata- -log database,what is also used for Orbit early warning and avoidance. It will provide technical support for the healthy on orbit operation of mega constellation in the future.","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115525471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The mechanism study of highly sensitive gas sensing based on double-layer graphene plasmons","authors":"Jiao Chi, Linchun Wang, X. Zhao","doi":"10.1117/12.2682127","DOIUrl":"https://doi.org/10.1117/12.2682127","url":null,"abstract":"The gas sensing based on graphene plasmons enhanced infrared absorption has the advantages of label-free identification of gas molecules, low loss and tunability. However, the optical field confinement of graphene plasmons is much smaller than distribution range of gas molecules, resulting in weak interaction between graphene plasmons and gas molecules. It is difficult to significantly improve the sensitivity of gas sensing. A gas sensor based on double-layer graphene nanoribbons with enhanced plasmons is proposed to improve the near-field coupling between highly confined field and gas molecules. Meanwhile, the influence mechanism of trapping free-gas molecules via surface adsorption is explored on increasing the sensitivity of gas sensing. The results show that the vibrational absorption enhancement of gas molecules based on double-layer graphene nanoribbons is improved by at least an order of magnitude than the single-layer graphene. The surface adsorption by graphene which tunes the gas concentration close to graphene can change the mode weight of vibrational mode to improve the sensitivity further. This study provides an important theoretical basis for designing and preparing gas sensor based on two-dimensional materials plasmons enhanced infrared absorption, and promotes the development of highly sensitive and integrated gas","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122008795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optical design of off-axis three-mirror reflective system by neural networks","authors":"Wan-qing Huang, Xibo Sun, Yu Xie, Yuanchao Geng, Lan-qin Liu, Wen-yi Wang, Ying Zhang","doi":"10.1117/12.2682144","DOIUrl":"https://doi.org/10.1117/12.2682144","url":null,"abstract":"We incorporate neural networks into the optical design of off-axis three-mirror reflective system, enabling us to achieve design outcomes without relying on iteration or ray tracing methods. Our approach involves combining analytical relations with neural networks during the design process, which yields results covering the entire parameter space with a single user input, and each design is scored simultaneously. Our results demonstrate that neural networks can simulate the complex relationship between performance requirements and structural parameters of an optical system. As such, the structural parameters can be directly obtained from the performance requirements, replacing the iterative optimization process traditionally used. This approach leads to relatively efficient and straightforward optical design. We anticipate that this method can be extended to various optical systems, reducing the experience threshold and difficulty of optical design.","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131932766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Underwater stratified model based on ARGO data and laser transmission characteristics","authors":"Xiaohu Tang, Pengfei Zhang, Fang Lu, Xiang’e Han","doi":"10.1117/12.2683126","DOIUrl":"https://doi.org/10.1117/12.2683126","url":null,"abstract":"With the development of photoelectric detection technology, blue-green laser underwater transmission and target detection have become a hot research field. At present, most of the underwater laser attenuation channel models regard seawater as a homogeneous medium, and a few layered models only consider the change of chlorophyll concentration with seawater depth, and the number of layers is small. This paper not only considers the influence of chlorophyll concentration, but also introduces the influence of temperature and salinity, increases the number of stratification intervals, and improves the seawater stratification model. Based on the measured data of temperature, salinity and chlorophyll concentration in the vertical direction of seawater provided by the Array for Real-time Geostrophic Oceanography data center website of China, the vertical distribution of seawater attenuation coefficient is given. Using this distribution, the seawater is stratified, and a more accurate vertical stratification model of seawater in the Pacific near Japan is established. Using the vertical stratification model of seawater established in this paper, the transmission process of blue-green laser underwater is simulated based on Monte Carlo method. The results show that with the increase of transmission distance, the number of photon packets on the receiving plane in layered seawater is always larger than that in uniform seawater. The photon packet energy on the receiving plane in the case of stratified seawater and the photon packet energy in the case of uniform seawater increase alternately, which provides a reference for the transmission characteristics of laser in actual seawater.","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130940452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Restoration of rotating Fourier transform ultraviolet Raman spectrum with a time sequences trigger method","authors":"Haitao Guo, Ming Tang","doi":"10.1117/12.2683101","DOIUrl":"https://doi.org/10.1117/12.2683101","url":null,"abstract":"Rotating Fourier transform ultraviolet Raman spectrometer (RFTURS) is an ideal and valuable tool for atmospheric CO2 detection. However, due to the short excitation wavelength and the nonlinear relationship between the optical path difference (OPD) and the rotating angle, it is difficult for RFTURS to produce linear interference signals. This paper proposes a time sequences trigger (TST) method to realize linear sampling of interference signals. Specifically, time sequences are designed at equidistant OPD intervals as external clocking signals to trigger the data acquisition (DAQ) card to sample interference signals. High angular resolution and precise time sequences are obtained by using a gearbox to work at low speed as well as detecting the OPD zero via a sensor, respectively. By a simulation spectrum and white light, the method was tested and ultimately obtained the expected restored spectrum, which addresses the current drawbacks such as large error of the non-uniform fast Fourier transform (NUFFT) method and the subsampling method, and unsuitable work conditions of the reference laser method performing at the UV. This work provides significant guidance for field measurement of atmospheric CO2 by RFTURS.","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133269769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guan Xiang, Binghuan Meng, Lin Han, Tingrui Sheng, Haiyue Ji, Shuang Li, Liang Sun, D. Luo, Jin Hong
{"title":"Analysis and correction of environmental differences in geometric performance of spaceborne optical instruments","authors":"Guan Xiang, Binghuan Meng, Lin Han, Tingrui Sheng, Haiyue Ji, Shuang Li, Liang Sun, D. Luo, Jin Hong","doi":"10.1117/12.2681808","DOIUrl":"https://doi.org/10.1117/12.2681808","url":null,"abstract":"High precision laboratory geometric calibration is the basis for the validity of on-orbit data of the Directional Polarimetric Camera. However, the difference in refractive index between the laboratory geometric calibration environment and the on-orbit vacuum environment can lead to changes in instrument geometric performance. The geometric performance difference of the instrument in the standard atmospheric environment and vacuum environment was analyzed by Zemax. The image point position deviation of the instrument in the two environments increases monotonically with the FOV. The image point position in the standard atmospheric environment is further away from the optical axis. When the FOV of the incident beam is 60o , the image points position deviation in all bands is greater than 1.42 pixels. Then, the laboratory carried out the environmental difference verification experiment based on the geometric performance verification light source. The experimental results are in good agreement with the Zemax analysis results, and the average deviation in the 670 nm band is less than 0.01 pixel. Finally, the laboratory geometric model parameters of the Directional Polarimetric Camera are corrected according to the Zemax analysis results. The corrected geometric model parameters will effectively improve the on-orbit geolocation and image registration accuracy of the Directional Polarimetric Camera.","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"135 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114016137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Performance analysis of moving average filtering used in TDLAS carbon dioxide sensing system","authors":"C. Yang, Lin Gui, Hao Lin, Pan Dai, Zijun Liu","doi":"10.1117/12.2683121","DOIUrl":"https://doi.org/10.1117/12.2683121","url":null,"abstract":"Reducing carbon emissions is a global priority due to human impact on atmospheric pollution and the greenhouse effect. Achieving carbon peak and neutrality requires real-time monitoring of CO2 concentrations. However, developing high-sensitivity, portable, and anti-jamming gas detection solutions is challenging. Among spectroscopic techniques, Tunable Diode Laser Absorption Spectroscopy (TDLAS) is highly sensitive for detecting CO2 concentrations. This paper elaborates on the principles of TDLAS for detecting CO2 concentrations and proposes a noise reduction algorithm to meet diverse environmental requirements. Simulations were performed using software to simulate CO2 absorption spectra at approximately 1.57866535μm under high-intensity noise (0.1mW - 1mW). Based on this simulation, we applied the Wavelength Modulation Spectroscopy (WMS) technique to calculate the ratio of the output differential signal's second harmonic intensity to the first harmonic S2f/1f(T) and output power to reduce light intensity influence and improve concentration inversion linearity. The weighted convolutional moving average filtering was utilized to optimize WMS denoising, utilizing weight transfer to make the process more precise and reliable. After analyzing various window functions, it was concluded that a window length of 9 would be the most optimal. The algorithm improved the signal-to-noise ratio (SNR) by 22.435% under these conditions. When the noise level increased fourfold from the original signal, the algorithm enhanced the SNR by 59.514%, enabling reliable CO2 monitoring even under challenging conditions.","PeriodicalId":130374,"journal":{"name":"Semantic Ambient Media Experiences","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114829226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}