A new method of estimating the frequency-known signals from the strong background noise was presented first. Then the new method was used in the demodulation of the digital frequency modulation (FSK) signals. The new ...A new method of estimating the frequency-known signals from the strong background noise was presented first. Then the new method was used in the demodulation of the digital frequency modulation (FSK) signals. The new demodulation method can complete the demodulation of the FSK signals only with the carrier frequency and without any carrier phase information. The simulation results show that the performance of anti-noise of the new method is better than that of the incoherent demodulation method and the fluctuation of the carrier phase has little effect on the new method. So the new demodulation method has a fine prospect in the practical applications.展开更多
Short baseline system (SBL), which is a kind of underwater acoustic locating technology, has widely applicable value. In order to examine the capability of ship model design, the ship model experimentation should have...Short baseline system (SBL), which is a kind of underwater acoustic locating technology, has widely applicable value. In order to examine the capability of ship model design, the ship model experimentation should have high accuracy. This paper focuses on the key techniques of high accuracy locating system, including high accuracy sub-array position emendation, divisional locating, anti multi-path interference measure, etc. Experiments show that the SBL locating systems has received the satisfying effect owing to these key techniques proposed in this paper.展开更多
A method of underwater simultaneous localization and mapping （SLAM） based on forward-looking sonar was proposed in this paper. Positions of objects were obtained by the forward-looking sonar, and an improved associa...A method of underwater simultaneous localization and mapping （SLAM） based on forward-looking sonar was proposed in this paper. Positions of objects were obtained by the forward-looking sonar, and an improved association method based on an ant colony algorithm was introduced to estimate the positions. In order to improve the precision of the positions, the extended Kalman filter （EKF） was adopted. The presented algorithm was tested in a tank, and the maximum estimation error of SLAM gained was 0.25 m. The tests verify that this method can maintain better association efficiency and reduce navigatioJ~ error.展开更多
基金the National Natural Science Foundation of China (60272077) the Science Foundation of Aeronautics (02F53030).
文摘A new method of estimating the frequency-known signals from the strong background noise was presented first. Then the new method was used in the demodulation of the digital frequency modulation (FSK) signals. The new demodulation method can complete the demodulation of the FSK signals only with the carrier frequency and without any carrier phase information. The simulation results show that the performance of anti-noise of the new method is better than that of the incoherent demodulation method and the fluctuation of the carrier phase has little effect on the new method. So the new demodulation method has a fine prospect in the practical applications.
文摘Short baseline system (SBL), which is a kind of underwater acoustic locating technology, has widely applicable value. In order to examine the capability of ship model design, the ship model experimentation should have high accuracy. This paper focuses on the key techniques of high accuracy locating system, including high accuracy sub-array position emendation, divisional locating, anti multi-path interference measure, etc. Experiments show that the SBL locating systems has received the satisfying effect owing to these key techniques proposed in this paper.
基金Supported by the National Natural Science Foundation of China(51009040)National Defence Key Laboratory of Autonomous Underwater Vehicle Technology(2008002)Scientific Service Special Funds of University in China(E091002)
文摘A method of underwater simultaneous localization and mapping （SLAM） based on forward-looking sonar was proposed in this paper. Positions of objects were obtained by the forward-looking sonar, and an improved association method based on an ant colony algorithm was introduced to estimate the positions. In order to improve the precision of the positions, the extended Kalman filter （EKF） was adopted. The presented algorithm was tested in a tank, and the maximum estimation error of SLAM gained was 0.25 m. The tests verify that this method can maintain better association efficiency and reduce navigatioJ~ error.
