A Novel Generalized Simulation Technology of Aerospace TT＆C Channel

A novel generalized simulation method is proposed to simulate the dynamic transmission delay of wideband and arbitrary signal in aerospace Tracking, telemetry and command （TT＆C） channel. This method orthogonally demodulates the wideband and arbitrary Radio-frequency （RF） signal into complex baseband by a Local oscillator （LO） signal. Then the method of dynamic interpolation and delay reconstruction is proposed to ob- tain the delay reconstruction signal of complex baseband signal based on the variation rules of satellite-to-earth loca- tion. Meanwhile, the method of satellite-to-earth distance subsection and polynomial fitting is applied to obtain the delay reconstruction signal of LO signal. The simulated output signal is achieved through the synthesis of two de- lay reconstruction signals mentioned above. The proposed method can accurately simulate the variation characteris- tics of time delay and Doppler when wideband and arbi- trary RF signal transmits in channel, without knowing any priori knowledge, such as signal form, signal parameters, and so on.     

Dynamic modeling and analyzing of a walking robot简

In this paper, a walking robot is established. The zero-moment point（ZMP） is used to stabilize the working robot. The kinematic model of the robot based on denavit-hartenberg（D-H） method is presented in this thesis. And then the dynamic model, based on Lagrange method, is built by simplifying the kinematic model of robot body. A kinematic simulation to the robotic system is achieved based on Adams. Driving torque of left ankle is calculated according to joint angle, angular velocity and angular acceleration. The validity of the dynamic model is testified by comparing with the result of simulation.     

Time Delay Estimation Based on Entropy Estimation

Abstract--This paper presents a novel time delay estimation （TDE） method using the concept of entropy. The relative delay is estimated by minimizing the estimated joint entropy of multiple sensor output signals. When estimating the entropy, the information about the prior distribution of the source signal is not required. Instead, the Parzen window estimator is employed to estimate the density function of the source signal from multiple sensor output signals. Meanwhile, based on the Parzen window estimator, the Renyi＇s quadratic entropy （RQE） is incorporated to effectively and efficiently estimate the high-dimensional joint entropy of the multichannel outputs. Furthermore, a modified form of the joint entropy for embedding information about reverberation （multipath reflections） for speech signals is introduced to enhance the estimator＇s robustness against reverberation.     

Random access preamble design based on time pre-compensation for LTE-satellite system

Because of the integration of long term evolution(LTE) technology and mobile satellite communication systems, uplink access technology for LTE-based geo-stationary earth orbit(GEO) satellite has become a popular research topic for satellite system. In order to solve the problem of unreasonable design for physical random access channel(PRACH) signal structure and reduce the effect of time uncertainty, this paper proposes a novel random access preamble based on time pre-compensation(TPC) for LTE-Satellite(LTE-S) system. In this scheme, by applying the method of non-linear least squares, the user terminal(UT) can use the receiving power to estimate the communication round trip delay(RTD) and based on the transmission delay of the beam center and the satellite, RTD can be compensated before transmission. Therefore, the preamble length and duration can be reduced without related to the maximum of RTD. In order to verify the performance of the scheme, the MATLAB is used to build a test system. The simulation results show that the proposed preamble satisfies the requirements of LTE-S system, and the better performance than previous researches is obtained.     

THE ANGLE ERROR ESTIMATE METHOD IN THE WIDE SWATH SAR BASING ON MULTI-RECEIVER

The wide-swath method based on multi-receiver is a novel and highly accurate wide-swath method, which requires a very precise view angle. The estimated angle has error because of the atmosphere refraction, angle error of view and target height. A method is proposed in this paper to estimate the angle error from the return signal. The method makes use of the relationship between the view angle error and the signal correlation of the subswaths to estimate the angle error. The precision of this method is analyzed by the law of great number and it turns out to be in direct proportion to the root square number of averaging. The simulation result is given and the angle precision is 0.025°.     

A NEW HYBRID WAVELET-KALMAN FILTER METHOD FOR THE ESTIMATION OF DYNAMIC SYSTEM

A new hybrid wavelet-Kalman filter method for the estimation of dynamic system is developed, Using this method, the real-time multiscale estimation of the dynamic system is implemented, and the observation equation established is for the object signal itself rather than its wavelet decomposition. The simulation results show that this method can be used to estimate the object＇s state of the stacked system, which is the foundation of multiscale data fusion; besides the performance of the new algorithm developed in the letter is almost optimal.     

NON-DESTRUCTIVE PAVEMENT LAYER THICKNESS MEASUREMENT USING EMPIRICAL MODE DECOMPOSITION WITH GPR

Ground Penetrating Radar （GPR） is an effective Non-Destructive Testing （NDT） technique for highway pavement surveys, which is able to acquire continuous pavement data compared with traditional core drilling method. In this study, we proposed an accurate and efficient method to estimate the thickness of each pavement layer using an air-coupled GPR system. For this work, the main difficulties are estimating each pavement layer＇s time delay and dielectric constant. We first give the basic signal model for pavement evaluation, and then present an Intrinsic Mode Functions （IMFs） product detector to determine each pavement layer＇s time delay. This method is based on Empirical Mode Decomposition （EMD）, which is an adaptive signal decomposition procedure and proved to be suitable for suppressing noises in GPR signal. The dielectric constant was determined by metal reflection measurement. The laboratory and highway experiments illustrate that the proposed thickness estimation method yields reasonable result, thus meets the requirements of practical highway pavement survey with massive GPR data.     

A Novel Multichannel Audio Signal Compression Method Based on Tensor Representation and Decomposition

Multichannel audio signal is more difficult to be compressed than mono and stereo ones. A novel multichannel audio signal compression method based on tensor representation and decomposition is proposed in this paper. The multichannel audio is represented with 3-order tensor space and is decomposed into core tensor with three factor matrices in the way of channel, time and frequency. Only the truncated core tensor is transmitted which will be multiplied by the pre-trained factor matrices to reconstruct the original tensor space. Objective and subjective experiments have been done to show a very noticeable compression capability with an acceptable output quality. The novelty of the proposed compression method is that it enables both high compression capability and backward compatibility with limited signal distortion to the hearing.     

Inter-Carrier Interference-Aware Sparse Time-Varying Underwater Acoustic Channel Estimation Based on Fast Reconstruction Algorithm

In this paper,a fast orthogonal matching pursuit(OMP)algorithm based on optimized iterative process is proposed for sparse time-varying underwater acoustic(UWA)channel estimation.The channel estimation consists of calculating amplitude,delay and Doppler scaling factor of each path using the received multi-path signal.This algorithm,called as OIP-FOMP,can reduce the computationally complexity of the traditional OMP algorithm and maintain accuracy in the presence of severe inter-carrier interference that exists in the time-varying UWA channels.In this algorithm,repeated inner product operations used in the OMP algorithm are removed by calculating the candidate path signature Hermitian inner product matrix in advance.Efficient QR decomposition is used to estimate the path amplitude,and the problem of reconstruction failure caused by inaccurate delay selection is avoided by optimizing the Hermitian inner product matrix.Theoretical analysis and simulation results show that the computational complexity of the OIP-FOMP algorithm is reduced by about 1/4 compared with the OMP algorithm,without any loss of accuracy.     

Detection and Ranging System of Flight Aid Lights

Dynamic detection based on optics sensors and ranging radars is a new method to detect the luminous intensity of flight aid lights. The optics sensors can get the illumination information of each light, the ranging radar gets the distance information, and then data amalgamation technology is used to compute the luminous intensity of each light. A method to modify the errors of this dynamic detection system is presented. It avoids the accumulation error and measurement carrier＇s excursion error by using peak value detection based on optics sensors to estimate the accurate position of each light, then to modify the lights＇ lengthways distance information and transverse position information. The performance of the detection and ranging system is validated by some experiments and shown in pictures.     

Data-mining based fault detection

This paper presents a fault-detection method based on the phase space reconstruction and data mining approaches for the complex electronic system. The approach for the phase space reconstruction of chaotic time series is a combination algorithm of multiple autocorrelation and Г-test, by which the quasi-optimal embedding dimension and time delay can be obtained. The data mining algorithm, which calculates the radius of gyration of unit-mass point around the centre of mass in the phase space, can distinguish the fault parameter from the chaotic time series output by the tested system. The experimental results depict that this fault detection method can correctly detect the fault phenomena of electronic system.     

Research on pulse edge extraction by using nonlinear optical fiber-loop mirror

The output characteristics of nonlinear optical fiber-loop mirror are analyzed in detail when the pump pulses with the same wavelength are input in the both directions for recovering the clock component of the signal spectrum.It is found that the double output pulses are produced in the transmission port of the nonlinear optical fiber-loop mirror.The output pulse peaks are located in time domain at the rising and falling edges of the pump pulses.It is demonstrated that the rising and falling edges of the pump pulse can be directly extracted by this method.Through numerical simulation,the effects of therelative delay of pump pulses and the dispersion of fiber on the characteristics of output pulses are studied.By spectrum analysis,it is found that the spectrum of output pulse sequence includes the clock components of the pump pulse sequence,and a new idea is provided for all-optical clock extraction.     

Multi-wavelength Čerenkov radiations in a microring resonator in combination with two gratings

In this paper, the ?erenkov radiation of light pulse in a microring and gratings is simulated and investigated. The system design consists of a two-defect grating incorporating a microring, connected with a uniform grating. In simulation, the continuous wave (CW) light pulse with wavelength centered at 1.55 µm is input into the microring device via the two-defect grating. The resonant outputs from the two-defect grating propagate through the microring and uniform grating, where the time delays of those two input pulses with different wavelengths through the system are distinguished by the output uniform grating. From the obtained resonant output pulses, we find that the red-shifted and blue-shifted ?erenkov pulses are observed. In applications, such a proposed system can be used to form two different optical delay pulses, in which the change in ?erenkov radiation of them, i.e., time delay within a microring device system, can be useful for ?erenkov radiation imaging and sensing applications.     

Implementation of Dynamic System Control Circuit Board Test System of Pure Electric Vehicles

The dynamic system control circuit board(DSCCB)is one of the most important components for dynamic system of pure electric vehicles. The current detection of the DSCCB is done manually, which is not only inefficient in the detection but also difficult to guarantee the data accuracy. In order to improve the detection efficiency and accuracy, a new testing system is designed by Labview. The total test time can be further reduced by about 75% compared with the results of the manual detection. In this paper, the three-parameter sine wave curve-fit algorithm theory is applied to the phase delay detection of the current sensor sampling circuit on the DSCCB. This method solves the problem of big error in the phase delay detection.     

电流模线性控制电荷泵的研究与设计

To meet the demands for a number of LEDs,a novel charge pump circuit with current mode control is proposed.Regulation is achieved by operating the current mirrors and the output current of the operational transconductance amplifier.In the steady state,the input current from power voltage retains constant,so reducing the noise induced on the input voltage source and improving the output voltage ripple.The charge pump small-signal model is used to describe the device’s dynamic behavior and stability.Analytical predictions were verified by Hspice simulation and testing.Load driving is up to 800 mA with a power voltage of 3.6 V,and the output voltage ripple is less than 45 mV.The output response time is less than 8μs,and the load current jumps from 400 to 800 mA.     

Design and simulation of a novel CMOS superimposed photodetector

A novel superimposed photodetector(PD)is put forward.The photodetector can obtain a couple of differential photocur-rent signals from one input optical signal.The light injection efficiency and the vertical work distance of this new photode-tector are much higher than those of the others.The superimposed photodetctor is designed based on the standard 0.18μm CMOS process.The responsivity,bandwidth and transient response of the photodetector are simulated by a commercial simulation software of ATLAS.The responsivities of two obtained photocurrent signals are 0.035 A/W and 0.034 A/W,while the bandwidths are 3.8 GHz and 5.2 GHz,respectively.A full differential optical receiver which uses the superim-posed photodetector as input is simulated.The frequency response and 4 Gbit/s eye diagram of the optical receiver are also obtained.The results show that the two output signals can be used as the differential signal.     

Device Design and Characteristics for SOA—based All Optical Signal 2R Regeneration

A new scheme based on SOA-MZI for all-optical 2R regeneration is proposed.The characteristics of gain and switching window of this device are investigated in detail.Numerical simulation results indicate that the nonlinear gain compression,the time delay between the input optical signal and the width of the optcial pulse are essential parameters for a good performance of all-optical 2R regeneration.     

Elastic Characteristic Extraction Method of Underwater Target Based on Adaptive Filtering

In this paper, a kind of elastic characteristic extraction method of underwater targets based on adaptive filtering is introduced. The kernel of the method is the recursive least square （RLS） algorithm. Firstly, the geometric scattering signal is fit by using the echo signal and the incident signal. Then, the frequency spectrum of the echo signal and the geometric scattering signal are calculated. At last, the frequency spectrum of the elastic scattering signal is obtained. The research of the simulation and lake experiment is carried on. As the results show, the formants of the elastic signal frequency spectrum can be precisely extracted by the algorithm, and the extraction algorithm can apply to extracting the elastic characteristic from the echo signal in a real underwater acoustics environment.     

Simple intra-signal-interference removing detector for HE-DCSK

In this paper, a novel simple detector is designed to remove the intra-signal interference in high efficiency differential chaos shift keying （HE-DCSK） modulation scheme. With the help of data bit estimated before correlation detection, this new detector could remove the modulated chaotic segment that would form intra-signal interference component in the correlator output from every received information-bearing signal in HE-DCSK, leading to greatly and effectively improved system bit error rate （BER） performance. The effectiveness of this proposed detector is studied analytically based on the numerical integration method and evaluated by computer simulation in additive-white-Gaussian- noise （AWGN） channel. Simulation results reveal that the proposed detector can dramatically improve the overall BER performance of HE-DCSK even at relatively low signal noise ratio （SNR） levels.     

State Estimation for Linear Constrained Systems with Unknown Input

This paper deals with the filtering problem for linear discrete constrained dynamic systems with unknown input. The constraint matrix and constraint vector in this system are allowed to vary in the value and in the dimension. The original full state is separated into two parts, and the estimate of the state is reduced to find the optimal estimate of a singular system. The estimable condition is researched and a recursive estimator for the original full state is presented. A rigorous mathematical induction is given to compare the performance of our approach to that of the existing method without constraint. A numerical example is presented to demonstrate the effectiveness of the new method.