Space-time processing for suppression of bottom reverberation
The major problem for sonars operating in shallow water is the detection of low Doppler targets in the presence of severe bottom reverberation. For a modern sonar with an azimuthally omni-directional transmitter; the Doppler of bottom reverberation is proportional to /spl nu/cos /spl theta/ where /spl nu/ is the speed of the sonar platform and /spl theta/ is measured from the bow or heading direction. For a towed array receiver, reverberation of various Doppler arriving on sidelobes limits the effectiveness of advanced waveforms. This smearing of sidelobe reverberation over a Doppler range of /spl plusmn//spl nu/ makes it difficult to detect targets with speeds less than that of the sonar platform. Standard adaptive beamforming algorithms are ineffective due to the conflict between desire for narrow frequency bins for good Doppler confinement and wide frequency bins for rapid convergence. We present space-time processing algorithms that overcome these difficulties and permit the detection of low Doppler targets from moving platforms.
Interference Suppression of Subarray Adaptive Beamforming in Presence of Sensor Dispersions
The capability to reject strong and spatially spread interferences by means of subarray adaptive beamforming in presence of sensor dispersions is analyzed. Subarray adaptive beamforming is a beamspace adaptive beamforming well suited for rapid convergence applications, and in which the degrees of freedoms are automatically allocated to the suppression of the strongest eigenvalues. The statistics of the array gain in presence of spatially spread jammers are derived and applied to the purpose of reverberation suppression in active sonar in Continuous Wave mode. Examples on real data are provided to support the theoretical results.
Research on automatic tracking solar power system
The paper elaborates the features of solar power. On the foundation of it, it analyses the composing, the theory and the features of solar power system of automatic tracking, analyzing the function of mental composing and the important technology, making a compartment of the amount of generation of solar power system of automatic tracking and that of common solar power system.