Presented here is a new adaptive state filtering algorithm for systems with multiplicative noise. This algorithm estimates the vector state of the system and the statistics of noise when all the statistics of noise ar...Presented here is a new adaptive state filtering algorithm for systems with multiplicative noise. This algorithm estimates the vector state of the system and the statistics of noise when all the statistics of noise are unknown. This filtering algorithm is a simple recursive structure. A simulation example is presented which demonstrates the effectiveness of this filtering algorithm.展开更多
This study applies a windowed frequency domain overlapped block filtering approach to acquire direct sequence signals. As a novel viewpoint, the windows not only allow pulse shaping without front-end pulse-shaping fil...This study applies a windowed frequency domain overlapped block filtering approach to acquire direct sequence signals. As a novel viewpoint, the windows not only allow pulse shaping without front-end pulse-shaping filter, but also increase the performance of the spectrum sensing unit, which can efficiently be implemented into this frequency domain receiver and may further be used for spectrum sensing in cognitive radios or narrowband interference cancellation in military radios. The proposed receiver is applicable for the initial time synchroni- zation of different signals containing a preamble. These signals include single carrier, constant envelope single carder, multicarrier, and even generalized multicarrier signals, making the proposed receiver structure a universal unit. Furthermore, the receiver can be used to perform filtering with long codes and compute the sliding correlation of an unknown periodic preamble. The receiver can further be modified to handle large Doppler shifts. We will also demonstrate herein the computational complexity and analysis of the acquisition performance in Rayleigh and Rician fading channels.展开更多
A satellite navigation receiver that can suppress jamming interference and spoofing interference simuhaneously is designed in this paper. An anti-jamming improved constrained spacial adaptive processing algorithm in s...A satellite navigation receiver that can suppress jamming interference and spoofing interference simuhaneously is designed in this paper. An anti-jamming improved constrained spacial adaptive processing algorithm in signal processing and an anti-spoofing M-estimator based extended Kalman filter algorithm in information processing are proposed respectively. Simulations of the integral designed anti-interferences satellite navigation receiver demonstrate that the designed anti-interferences receiver can suppress jamming signals efficiently （ above 40 dB） and ensure the normal reception of satellite signals while satellite signals and jamming signals have the similar direction of arrival （ almost 10° ）. The designed anti-interference receiver can effectively eliminate the influence of spoofing signals on the navigation solution accuracy and maintain high accuracy of position and velocity estimation, which improves the anti-jamming and anti-spoofing capability of the satellite navigation receiver.展开更多
In this paper, we propose an additional noise-free, independent center frequency and bandwidth tunable optical filter based on stimulated Brillouin scattering(SBS) losses. By suppressing the out-of-band signal with tw...In this paper, we propose an additional noise-free, independent center frequency and bandwidth tunable optical filter based on stimulated Brillouin scattering(SBS) losses. By suppressing the out-of-band signal with two broadened symmetric SBS losses, tunable pass bandwidths from 500 MHz to 9.5 GHz and the independent center frequency tunability are demonstrated. Considering the limited SBS interaction in the center frequency range,a flat-top response with minimum 0.3 dB ripple is achieved. Assisted by the extra suppression from polarization pulling, a maximum selectivity of 20 dB and an ultrahigh 250 dB∕GHz roll-off are reached. A gain-based SBS filter adds noise to the filtered signal. However, for our proposed filter setup, no additional noise is detected due to the transparency in the passband. Considering the wide independent bandwidth and center frequency tunability, flat-top response, and low-noise characteristic, our proposed filter can be perfectly used as a supplement of most commercialized conventional tunable optical single bandpass filters, whose minimum bandwidth is limited by 10 GHz.展开更多
文摘Presented here is a new adaptive state filtering algorithm for systems with multiplicative noise. This algorithm estimates the vector state of the system and the statistics of noise when all the statistics of noise are unknown. This filtering algorithm is a simple recursive structure. A simulation example is presented which demonstrates the effectiveness of this filtering algorithm.
文摘This study applies a windowed frequency domain overlapped block filtering approach to acquire direct sequence signals. As a novel viewpoint, the windows not only allow pulse shaping without front-end pulse-shaping filter, but also increase the performance of the spectrum sensing unit, which can efficiently be implemented into this frequency domain receiver and may further be used for spectrum sensing in cognitive radios or narrowband interference cancellation in military radios. The proposed receiver is applicable for the initial time synchroni- zation of different signals containing a preamble. These signals include single carrier, constant envelope single carder, multicarrier, and even generalized multicarrier signals, making the proposed receiver structure a universal unit. Furthermore, the receiver can be used to perform filtering with long codes and compute the sliding correlation of an unknown periodic preamble. The receiver can further be modified to handle large Doppler shifts. We will also demonstrate herein the computational complexity and analysis of the acquisition performance in Rayleigh and Rician fading channels.
文摘A satellite navigation receiver that can suppress jamming interference and spoofing interference simuhaneously is designed in this paper. An anti-jamming improved constrained spacial adaptive processing algorithm in signal processing and an anti-spoofing M-estimator based extended Kalman filter algorithm in information processing are proposed respectively. Simulations of the integral designed anti-interferences satellite navigation receiver demonstrate that the designed anti-interferences receiver can suppress jamming signals efficiently （ above 40 dB） and ensure the normal reception of satellite signals while satellite signals and jamming signals have the similar direction of arrival （ almost 10° ）. The designed anti-interference receiver can effectively eliminate the influence of spoofing signals on the navigation solution accuracy and maintain high accuracy of position and velocity estimation, which improves the anti-jamming and anti-spoofing capability of the satellite navigation receiver.
文摘In this paper, we propose an additional noise-free, independent center frequency and bandwidth tunable optical filter based on stimulated Brillouin scattering(SBS) losses. By suppressing the out-of-band signal with two broadened symmetric SBS losses, tunable pass bandwidths from 500 MHz to 9.5 GHz and the independent center frequency tunability are demonstrated. Considering the limited SBS interaction in the center frequency range,a flat-top response with minimum 0.3 dB ripple is achieved. Assisted by the extra suppression from polarization pulling, a maximum selectivity of 20 dB and an ultrahigh 250 dB∕GHz roll-off are reached. A gain-based SBS filter adds noise to the filtered signal. However, for our proposed filter setup, no additional noise is detected due to the transparency in the passband. Considering the wide independent bandwidth and center frequency tunability, flat-top response, and low-noise characteristic, our proposed filter can be perfectly used as a supplement of most commercialized conventional tunable optical single bandpass filters, whose minimum bandwidth is limited by 10 GHz.
