摘要 :
In order to ensure the reliability of satellite data, it is necessary to test the authenticity of satellite products during the
operation of ocean color satellite in orbit. Therefore, it is significant to obtain accurate sea surfa...
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In order to ensure the reliability of satellite data, it is necessary to test the authenticity of satellite products during the
operation of ocean color satellite in orbit. Therefore, it is significant to obtain accurate sea surface field data, which can
provide source data for the authenticity test of satellite products. At present, the main means of acquiring data at sea in
China is still large-scale voyage test on board ships. This method needs high cost and requires a lot of manual operation,
and the efficiency of acquiring data is extremely limited. However, a large amount of observation data can be obtained by
establishing long-term automatic observation stations at sea, and the cost is low. In this paper, the continuous observation
data of atmospheric optical parameters obtained by CE318 solar photometer installed on Wenzhou offshore platform in
Zhejiang Province are analyzed based on the data processing method of AERONET. Combined with the actual situation,
the automatic observation data of atmospheric optical parameters at sea are qualitatively controlled and verified by satellite
data. Finally, a data quality control scheme for automatic observation of atmospheric optical parameters at sea is proposed.
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摘要 :
In order to ensure the reliability of satellite data, it is necessary to test the authenticity of satellite products during the
operation of ocean color satellite in orbit. Therefore, it is significant to obtain accurate sea surf...
展开
In order to ensure the reliability of satellite data, it is necessary to test the authenticity of satellite products during the
operation of ocean color satellite in orbit. Therefore, it is significant to obtain accurate sea surface field data, which can
provide source data for the authenticity test of satellite products. At present, the main means of acquiring data at sea in
China is still large-scale voyage test on board ships. This method needs high cost and requires a lot of manual operation,
and the efficiency of acquiring data is extremely limited. However, a large amount of observation data can be obtained by
establishing long-term automatic observation stations at sea, and the cost is low. In this paper, the continuous observation
data of atmospheric optical parameters obtained by CE318 solar photometer installed on Wenzhou offshore platform in
Zhejiang Province are analyzed based on the data processing method of AERONET. Combined with the actual situation,
the automatic observation data of atmospheric optical parameters at sea are qualitatively controlled and verified by satellite
data. Finally, a data quality control scheme for automatic observation of atmospheric optical parameters at sea is proposed.
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摘要 :
Battlefield situational awareness is the core condition that determines the success or failure of the battlefield, and it is also an important application direction of photodetectors. The rapid development of AI technology in rece...
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Battlefield situational awareness is the core condition that determines the success or failure of the battlefield, and it is also an important application direction of photodetectors. The rapid development of AI technology in recent years is about to cause major changes in future wars. The new AI battlefield will also put forward new urgent needs for situational awareness. This article summarizes the current main modes of collaborative detection of battlefield situation awareness and its research status, including radar / infrared composite detection, multi-source data fusion of radar / infrared detection, cooperative target recognition, target tracking, etc. On this basis, combined with the current development trend of the intelligence level of the main battlefield equipment, we get the development needs of future intelligent battlefield situational awareness for new types of collaborative detection, including requirements for its style, angle, speed, and detection targets of distributed collaborative detection. Based on this, the key development directions and core issues to be solved for intelligent battlefield situational awareness in the future are proposed.
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摘要 :
Take-off and landing performance, which is supposed to satisfy high standard and always plays an important role during the whole lifespan of an aircraft, is necessary to be fully considered and systematically evaluated during the ...
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Take-off and landing performance, which is supposed to satisfy high standard and always plays an important role during the whole lifespan of an aircraft, is necessary to be fully considered and systematically evaluated during the designing process. In this paper, aiming at determining the take-off and landing demands for low-cost UAVs, aero-dynamic analysis and mechanical modeling are launched to calculate the key parameters of related take-off and landing performance. According to different conditions of application, two theoretical models for take-off as well as two for landing process are established in detail, and an original method for correcting aerodynamic drag and fric-tion is proposed. The calculating methods for the time and distance during take-off and landing period are provided while simulation based on MATLAB is carried out to visually present the results. Based on the output of calculation and numerical analysis, the effectiveness and feasibility of the models are verified. The results indicate that the models proposed in this paper are efficient to estimate the take-off and landing performance of low-cost UAVs and also provide rapid and convenient support to carry out demands analysis and the design of low-cost UAVs especially in the preliminary phase.
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摘要 :
With the broad application of satellite navigation technique in the society and economy development, the satellite navigation technique has been facing with more and more hidden dangers of being attacked in such key fields as fina...
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With the broad application of satellite navigation technique in the society and economy development, the satellite navigation technique has been facing with more and more hidden dangers of being attacked in such key fields as finance, public security, civil aviation and public rescue. In light of the vulnerability of satellite navigation receiver against replay attack in the above fields, this paper proposes several anti-replay attack techniques of low complexity, i.e., inertial positioning test, clock skew test and Doppler shift test. The simulation results show that Doppler shift test can resist replay attack effectively without additional hardware to the receiver. In addition, compared to SNR test, absolute power test and the other techniques, Doppler shift test has the advantages of low implementation difficulty and high adaptability, which can provide technical support for the security applications of satellite navigation technology in the fields of great concern.
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摘要 :
With the broad application of satellite navigation technique in the society and economy development, the satellite navigation technique has been facing with more and more hidden dangers of being attacked in such key fields as fina...
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With the broad application of satellite navigation technique in the society and economy development, the satellite navigation technique has been facing with more and more hidden dangers of being attacked in such key fields as finance, public security, civil aviation and public rescue. In light of the vulnerability of satellite navigation receiver against replay attack in the above fields, this paper proposes several anti-replay attack techniques of low complexity, i.e., inertial positioning test, clock skew test and Doppler shift test. The simulation results show that Doppler shift test can resist replay attack effectively without additional hardware to the receiver. In addition, compared to SNR test, absolute power test and the other techniques, Doppler shift test has the advantages of low implementation difficulty and high adaptability, which can provide technical support for the security applications of satellite navigation technology in the fields of great concern.
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摘要 :
Based on the infrared temperature measurement technology, in this paper, the effect of the purge flow from the upstream slot on the film cooling performance of the annular cascade endwall was studied experimentally. GE's E~3 turbi...
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Based on the infrared temperature measurement technology, in this paper, the effect of the purge flow from the upstream slot on the film cooling performance of the annular cascade endwall was studied experimentally. GE's E~3 turbine first stage stator blades is selected as the experimental reference blade type in this experiment. In the current experiment, effects of different slot locations, slot ejection angles and slot profiles on the endwall film cooling effectiveness were taken into account. Under the influence of endwall secondary flow, the film cooling is mainly concentrated on the front part of the channel and close to the suction side of the blade, while there is almost no cooling effect close to the pressure side of the blade in the channel. With the increase of the distance between the blade leading edge and the slot, the endwall film cooling performance is reduced. While the distance increasing from 0.15C_x to 0.45C_x, and the peak endwall film cooling effectiveness is reduced by 78%, 68% and 58% respectively when the mass flow ratio (MFR) is 1.0%, 1.5%, and 2.0%. As the slot ejection angle is reduced, the endwall film cooling performance can be effectively improved. When the slot ejection angle increased from 45° to 90° , the peak endwall film cooling effectiveness decreases by 17%, 15%, and 13% respectively at the mass flow ratio (MFR)=1.0%,1.5% and 2.0%. And the convergent slot can effectively improve the endwall cooling film formed by slot jet compared to the reference slot. When the mass flow ratio are MFR=1.0%, 1.5%, and 2.0%, the peak endwall film cooling effectiveness at the convergent slot is increased by 50%, 20%, and 15% comparing to the reference slot.
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摘要 :
Based on the infrared temperature measurement technology, in this paper, the effect of the purge flow from the upstream slot on the film cooling performance of the annular cascade endwall was studied experimentally. GE's E~3 turbi...
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Based on the infrared temperature measurement technology, in this paper, the effect of the purge flow from the upstream slot on the film cooling performance of the annular cascade endwall was studied experimentally. GE's E~3 turbine first stage stator blades is selected as the experimental reference blade type in this experiment. In the current experiment, effects of different slot locations, slot ejection angles and slot profiles on the endwall film cooling effectiveness were taken into account. Under the influence of endwall secondary flow, the film cooling is mainly concentrated on the front part of the channel and close to the suction side of the blade, while there is almost no cooling effect close to the pressure side of the blade in the channel. With the increase of the distance between the blade leading edge and the slot, the endwall film cooling performance is reduced. While the distance increasing from 0.15C_x to 0.45C_x, and the peak endwall film cooling effectiveness is reduced by 78%, 68% and 58% respectively when the mass flow ratio (MFR) is 1.0%, 1.5%, and 2.0%. As the slot ejection angle is reduced, the endwall film cooling performance can be effectively improved. When the slot ejection angle increased from 45° to 90° , the peak endwall film cooling effectiveness decreases by 17%, 15%, and 13% respectively at the mass flow ratio (MFR)=1.0%,1.5% and 2.0%. And the convergent slot can effectively improve the endwall cooling film formed by slot jet compared to the reference slot. When the mass flow ratio are MFR=1.0%, 1.5%, and 2.0%, the peak endwall film cooling effectiveness at the convergent slot is increased by 50%, 20%, and 15% comparing to the reference slot.
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