Abstract: In the signal combining system of deep space network, the estimation error of time-delay between signals will reduce the effectiveness. The time-delay alignment technique based on combined output signal as the reference (CC-SUMPLE algorithm) makes use of the mutual information offered by multi-antenna and improves the alignment performance. However, it only takes ordinary cross-correlation into consideration rather than the cyclostationary of digital communication signal during calculating time-delay in the iterative process. As to this problem, this paper proposes multi-antenna signal time-delay alignment algorithm based on cyclostationary of communication signal (MCCC-SUMPLE algorithm) which reconstructs the combined reference signal and takes advantage of multi-cycle frequencies. The simulation results show that the proposed algorithm will improve the estimation accuracy and time-delay alignment performance compared with CC-SUMPLE algorithm.
Abstract: The implementation of PBN is an important part of China's civil aviation to enhance national strength program,the evaluation of the ground-based navigation signal Overlay is an essential part of the design of flight procedures.This article start from the principle of electromagnetic wave propagation in the atmosphere and establish a reasonable mathematical model for the propagation of electromagnetic signals,then make use of the secondary development for ArcGIS to complete the evaluation system of Ground-based navigation signal overlay while considering the requirements of DME / DEM update area for 2 DME station.
Abstract: In this paper, we designed an automatic system and automatic test software, and they can carry out Kunming rats bioelectromagnetic measurement in standard status and anesthesia automatically in anechoic chamber where the electromagnetic field outside is shielded, the reflection wave is absorbed, and the measurement accuracy will be improved. We get a great number of measurement data with frequency-sweep measurement method. The mean and standard deviation of amplitudes vs. frequencies is calculated and analyzed. The results show the measurement method is feasible. We have plotted the means of measured data as multiple sets of Y values in a series of bars with standard deviations bars included and distributed in the frequency axis of X. It is found that the fluctuation of the mean and standard deviation in some frequencies is not evident which may explain frequency window effects, while in other frequencies, such a fluctuation can be obviously observed, which may suggest that bioelectromagnetic signal is influenced by biological activities (standard and anaesthesia status) in these frequency points.
Abstract: To deal with the lack of effective experimental data under the current condition for gearbox fault pattern recognition, the Wind Turbine Drivetrain Diagnostics Simulator (WTDS) was used for experimental investigation and gained large number of gear fault samples. The wavelet transform is employed to decompose the vibration signal to obtain the energy ratio in each frequency band. Taking energy ratios as feature vectors, the pattern recognition results are obtained by the support vector classification (SVC). The experimental results show that the hybrid approach is robust to noise and has high classification accuracy.
Abstract: This paper designed a multiple channel audio acquisition system based on FPGA and ARM. On the one hand, the system uses FPGA as the core, realize high speed logic control and the AD interface control unit. On the other hand, the ARM is responsible for the logic control and the realization of the HumanMachine Interaction, and to save the audio data to the SD card. The system has the advanced of low power consumption, real-time and high scalability. Therefore, we can implement the reliable and lower cost acquisition system of multi-channel audio signal.
Abstract: A new method for bearing fault diagnosis is proposed based on Probabilistic Principal Component Analysis (PPCA) and Cyclic Bispectrum (CB). The first procedure is signal de-noised using PPCA and the second procedure is the CB analysis. The effectiveness of the proposed method is demonstrated by numerical simulation and experimental investigation of a rolling bearing with outer race fault.
Abstract: In this paper, we investigate the structure of k-circulant matrices, and then present some new properties of k-circulant matrices.
Abstract: The orthogonality of transmitting signals affects the performance of Muitple Input Mulitiple Output (MIMO) radar system. The chaotic signals was adopted at the transmitter to achieve the approximate orthogonal. A signal separation aprroach for MIMO Radar based on the particle filter in Non-Gaussian clutter environment was proposed. Before the match filter (MF), the particle filter is quite suitable for chaotic signals separation. Simulation results show that the proposed algorithm can realize a good separation performance. At the receiver, the coherent processing results show that this method has the better target resolution ability than the tranditional match filter alone.
Abstract: This paper describes that at high frequencies the reflection signal from an underwater target can be seen as the sum of an individual echo from certain equivalent scattering centers as such an underwater target can be characterized by highlights distributed within a spatial target structure. By analyzing the highlight structure of an underwater target echo, the synthesized echo signal can be simulated. In this paper, a submarine model is selected to analyze the echo characteristic of submarine based on highlight model. The simulation experiment results show that the model is a very reasonable two-dimensional acoustic representation of a submarine. The results also indicate that the highlight model can be applied to acoustic countermeasure system, which has an important application value.