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...
展开
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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A novel linear ion trap is designed and being tested which permits storage of a large number of ions with reduced susceptibility to the second-order Doppler effect caused by the RF confining fields. This trap should store about 20...
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A novel linear ion trap is designed and being tested which permits storage of a large number of ions with reduced susceptibility to the second-order Doppler effect caused by the RF confining fields. This trap should store about 20 times the number of ions storable by a conventional RF trap, with no corresponding increase in second-order Doppler shift from the confining field. In addition the sensitivity of this shift to trapping parameters, i.e. RF voltage, RF frequency, and trap size, is greatly reduced. Mercury ions and xenon ions are trapped in the presence of helium buffer gas. Trap times as long as 2*10/sup 3/ s have been measured.
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In this paper, we discuss the use of the RF Wireless Network Environment emulator. Its architecture and capabilities are investigated. Four case studies of the RF network emulator are presented in this paper. The first case study ...
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In this paper, we discuss the use of the RF Wireless Network Environment emulator. Its architecture and capabilities are investigated. Four case studies of the RF network emulator are presented in this paper. The first case study simulates the slow-hopping anti-jamming waveform. The second case study is the application of spectrum masking, the third is the use of power difference of arrival localization algorithm to triangulate the location of a local unknown emitter and the fourth utilizes the emulator for testing and verification of a Multiple Link Common Data Link System. The network architecture and setup of the environment emulator for each case is discussed in detail.
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摘要 :
In this paper, we discuss the use of the RF Wireless Network Environment emulator. Its architecture and capabilities are investigated. Four case studies of the RF network emulator are presented in this paper. The first case study ...
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In this paper, we discuss the use of the RF Wireless Network Environment emulator. Its architecture and capabilities are investigated. Four case studies of the RF network emulator are presented in this paper. The first case study simulates the slow-hopping anti-jamming waveform. The second case study is the application of spectrum masking, the third is the use of power difference of arrival localization algorithm to triangulate the location of a local unknown emitter and the fourth utilizes the emulator for testing and verification of a Multiple Link Common Data Link System. The network architecture and setup of the environment emulator for each case is discussed in detail.
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The contribution of this paper is the derivation of a GLRT (generalized likelihood ratio test) detector and a suboptimal cyclic-correlation-based estimator of Doppler shift and Doppler rate, the chirp parameters, for a signal with...
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The contribution of this paper is the derivation of a GLRT (generalized likelihood ratio test) detector and a suboptimal cyclic-correlation-based estimator of Doppler shift and Doppler rate, the chirp parameters, for a signal with fluctuating random amplitude embedded in correlated compound-Gaussian clutter. The hybrid Cramer-Rao lower bounds (HCRLBs) are also derived for a Swerling I target signal. Simulation examples are provided to show the behavior of the proposed estimator under different non-Gaussian scenarios.
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The authors propose a new spectral analysis technique for Doppler radar. They present some limitations of classical methods which motivate their study. Particularly they insist on bias introduced on the wind speed profile in the c...
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The authors propose a new spectral analysis technique for Doppler radar. They present some limitations of classical methods which motivate their study. Particularly they insist on bias introduced on the wind speed profile in the case of wind shear and strong variations of the reflectivity. In order to improve this behaviour, they introduce a realistic backscattered wave modeling based on stratification of the range gate. Regularisation is necessary to compensate observation limitation specially for some range gates where the SNR is poor. For this purpose they introduce a parametric wind speed profile, to take into account spatio-temporal continuity. They propose a second order steepest descent algorithm which recursively fits the parametric spectrum to the observation. Simulation results demonstrate the expected improvement. The algorithm is also tested on real data.
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The next century's advanced weather radars will be able to accommodate pulse compression waveforms and phased array electronically scanned antennas to meet higher time and space resolution requirements. We have investigated severa...
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The next century's advanced weather radars will be able to accommodate pulse compression waveforms and phased array electronically scanned antennas to meet higher time and space resolution requirements. We have investigated several coded waveforms and compression filters for weather radar applications. Candidate waveforms include Barker bi-phase coded as well as linear and non-linear FM coded waveforms. Minimum integrated sidelobe (inverse) filters are demonstrated to be superior to matched filters for compression processing of distributed weather echoes. We describe the Doppler sensitivity of the waveform and filters by plotting the integrated and peak sidelobe ratios vs. Doppler shift. We demonstrate these effects on both ground clutter and 50 dB reflectivity transition weather data taken with the 3 cm ELDORA testbed radar.
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A theory of deformation of the thin flat mirror, which vibrates harmonically in the direction of the normal to its surface, is shortly introduced in our work. Vibrating thin flat mirrors are used in various areas of science and en...
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A theory of deformation of the thin flat mirror, which vibrates harmonically in the direction of the normal to its surface, is shortly introduced in our work. Vibrating thin flat mirrors are used in various areas of science and engineering, e.g. in optical measurement systems. These mirrors can be generally deformed with respect to environmental conditions during measurements. The mirror deformation is closely related to the dynamic wave aberration of the wave-front, reflected from the mirror. The consequence of the wave aberration is a spatially inhomogeneous frequency shift of the light reflected from the vibrating mirror. The influence of the wave aberration on the frequency shift is studied theoretically and examples are given.
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摘要 :
A theory of deformation of the thin flat mirror, which vibrates harmonically in the direction of the normal to its surface, is shortly introduced in our work. Vibrating thin flat mirrors are used in various areas of science and en...
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A theory of deformation of the thin flat mirror, which vibrates harmonically in the direction of the normal to its surface, is shortly introduced in our work. Vibrating thin flat mirrors are used in various areas of science and engineering, e.g. in optical measurement systems. These mirrors can be generally deformed with respect to environmental conditions during measurements. The mirror deformation is closely related to the dynamic wave aberration of the wave-front, reflected from the mirror. The consequence of the wave aberration is a spatially inhomogeneous frequency shift of the light reflected from the vibrating mirror. The influence of the wave aberration on the frequency shift is studied theoretically and examples are given.
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