Table of Content

30 March 2011, Volume 45 Issue 03 Previous Issue    Next Issue

Radiao Electronics, Telecommunication Technology

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Twodimensional Cross Entropy Thresholding Based on Chaotic Resilient Particle Swarm Optimization or Decomposition WU Yi-Quan, ZHANG Xiao-Jie, WU Shi-Hua 2011, 45 (03):  301-0307.  Abstract ( 4385 )   Save A twodimensional cross entropy image thresholding method based on chaotic resilient particle swarm optimization (CRPSO) or decomposition was proposed. Firstly, chaotic resilient particle swarm optimization was used to find the optimal threshold of twodimensional cross entropy method. The recursive algorithm was adopted to avoid the repetitive computation of fitness function in iterative procedure. As a result, the computing speed was improved greatly. Then, the computation of twodimensional cross entropy method was converted into two onedimensional spaces, which made the computation complexity further reduce from O(L2) to O(L). The experimental results show that, the two methods proposed in this paper can greatly reduce the running time while the segmented result is as good as or better than the existing twodimensional cross entropy thresholding method. References | Related Articles | Metrics

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A Novel ICI Cancellation Algorithm Based on Channel Segmentationcascade in OFDM System XU Xing-Hui, HE Chen 2011, 45 (03):  308-0312.  Abstract ( 3859 )   Save  For Orthogonal Frequency Division Multiplexing (OFDM) wireless systems with high frequency, deficiencies caused by Doppler frequency offset and the carrier phase noise are much higher，which will introduce InterCarrier Interference (ICI) and degrade the performance. Using channel segmentation，an equivalent method was presented in this paper，which transfers linear timevariant channel into the cascading of timeinvariant channel and timevariant channel with no delay. Then onedimensional equalization can be achieved at the receiver to suppress ICI, avoiding calculating the frequency domain channel response matrix and its inverse matrix. The analysis and simulation results show that, the proposed algorithm can effectively reduce the complexity to O(N) with almost no performance loss, compared to the existing low complexity MMSE. References | Related Articles | Metrics

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Adaptive limited feedback for MUMIMO system WU Youlong,LUO Hanwen,LIU Wei,DING Ming,Wang Hailong 2011, 45 (03):  313-0320.  Abstract ( 4584 )   Save The limited feedback in multiuser MultipleInput MultipleOutput (MUMIMO) systems is addressed in this paper. In order to reduce the feedback overhead in the uplink channel, we analyze the relation between user’s feedback bits and rate, deduce the optimal solution for adaptive limited feedback, and propose a suboptimal feedback scheme which is more practical. In this scheme, users choose the feedback bits according to both their channel gains and the average gain of the system. Users with high SNR are assigned with more feedback bits than the lowSNR users so as to improve the feedback efficiency. Simulation results and analysis show that the proposed scheme is easytoimplement and can enhance the throughput with no additional feedback overhead. References | Related Articles | Metrics

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Energy Consumption Analysis and Improvement Strategy for ClusterHead Rotation in Wireless Sensor Networks DENG Han-Lin, LI Lei, HUANG He-Qing, YUAN Xiao-Bing, WANG Ying-Guan 2011, 45 (03):  321-0326.  Abstract ( 4263 )   Save To design a more energyefficient cluster head rotation (CHR) strategy for wireless sensor networks, this paper built an analytical model for the energy consumption of contentionbased CHR, analyzed the energy consumption ratio between data gathering and CHR, and proposed a schedulebased CHR, which could remove the energy consumption in CHR. The simulation results show that the schedulebased CHR obviously improves energy efficiency and energy consumption balance in the cluster. References | Related Articles | Metrics

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Fast Computation of Walsh Spectrum of  Affine Function over the Ring Z/2n CHANG Ya-Qin, JIN Chen-Hui 2011, 45 (03):  321-0326.  Abstract ( 2515 )   Save According to the property of carry function of affine function over the ring Z/2n, this paper gave out the fast computation algorithm of the Walsh spectrum of affine function and multioutput affine function over the ring Z/2n. The experiments show that the algorithm can reduce the computation complexity from logtime to linear time about n. References | Related Articles | Metrics

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AlN Thin Film Resonator Operated in  Thickness Shear Mode Excited by Lateral Electric Field Chen-Da, LI De-Hua, SONG Hong-Wei, WANG Cui-Ling, ZHANG Yu-Ping 2011, 45 (03):  327-0330.  Abstract ( 4179 )   Save Thin film bulk acoustic resonators operated in shear mode have promising applications in biochemical sensors. The shear mode AlN solid mounted resonator using lateral field excitation was presented. The resonator configuration consists of the highly coriented AlN piezoelectric film, the parallel electrodes on the film surface and the threeperiod SiO2/W acoustic Bragg reflector. The electric field characteristics were calculated by finite element modeling in order to design the electrode frame. The testing results of the finished device show that the pure shear mode wave can be excited at 2 GHz. The quality factor (Qs and Qp) and the effective electromechanical coupling content (K2eff) is 434, 393 and 0.97 %, respectively. The longitudinal wave is restrained by the effective lateral electric field and the frequency selectivity of the acoustic reflector. References | Related Articles | Metrics

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A Relay Scheduling Algorithm in DualHop Wireless Networks Zhang-Yu, LUO Han-Wen, ZHOU Xiao-Lin 2011, 45 (03):  331-0335.  Abstract ( 3902 )   Save This paper proposed a relay node iterative scheduling algorithm based on the channel capacity maximization for dualhop wireless networks. Based on the amplifyandforward relay protocol, the proposed algorithm selects relay nodes iteratively according to the criterion which makes the instantaneous capacity maximal when the destination node performs the joint decoding. The selection process continues until the number of the selected relays is equal to the number of source transmitting antennas or the channel capacity does not increase anymore. The simulation results show that under different conditions including total number of relay nodes, number of source transmitting antennas and signal to noise ratios of the forward and backward channels, the algorithm can obtain greater capacity gains and multirelay diversity gains over conventional algorithms and can reach the upper bound of the informationtheoretic capacity more closely. Related Articles | Metrics

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Frequency Planning in RelayAided Cellular Network LIN Yi-Ru-1, GUO Jia-1, LUO Han-Wen-1, ZHOU Xiao-Lin-2 2011, 45 (03):  336-0339.  Abstract ( 4470 )   Save This paper proposes a new frequency planning scheme for the proposed cellular wireless system using fix relay. Our scheme improves the frequency efficiency, while relatively improving the CEU’s SIR through frequency planning based on fractional frequency reuse. The simulation results show that it can improve the performance of frequency efficiency compared with others scheme, CEU’s average throughput is improved. References | Related Articles | Metrics

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Grating Lobe Suppression for Contiguous Subarray with Uniform Structure CHEN Bi-Xian, JIN Rong-Hong, GENG Jun-Ping, LIANG Xian-Ling 2011, 45 (03):  340-0344.  Abstract ( 5321 )   Save  When large scale arrays are divided into subarrays of equal sizes a difficulty with grating lobes is encountered during scanning. The condition of producing the grating lobe was discussed at first, and on this basis, a new method of beam scanning at uniform subarray level was proposed for the purpose of reducing the grating lobe by dividing the scanning region. The fundamental rules of scanning regional division and how to optimize the weights of all angles in each scanning region at elements level and subarray level by particle swarm optimization (PSO) were also discussed. As an example, an array of three subarray with four elements was simulated and the results show that the maximum sidelobe level can be reduced to -22 dB in each scanning region. This approach also can be used for multibeam forming. References | Related Articles | Metrics

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A Method for Multitarget Passive Location by a Movable Single Station  Based on Weighted MUSIC Algorithm in FRFT Domain HE Wei-Yan, JIN Rong-Hong, GENG Jun-Ping, LIANG Xian-Ling 2011, 45 (03):  345-0349.  Abstract ( 4446 )   Save Aiming at the situation of multiple linear frequency modulation(LFM) signal sources, by analyzing the Doppler shift of received signals, a multicomponent LFM signal model for the antenna array on a movable single station was built. Then a method for multitarget passive location based on weighted MUSIC algorithm in fractional Fourier transformation(FRFT) domain was presented, which implements the detection and DOA estimation of multitarget signals at low SNR. The simulation results show that  multiple targets with similar frequency and close space can be distinguished in a high accuracy. algorithm References | Related Articles | Metrics

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A User Pairing Algorithm for Virtual MIMO Systems Jiang-Wu-Yang, LIU Wei, DING Ming, LUO Han-Wen 2011, 45 (03):  350-0353.  Abstract ( 4566 )   Save A novel user pairing algorithm for virtual MIMO systems was proposed based on semiorthogonal user selection (SUS) with partial inverse selection. To solve the problem that users with bad channel condition suffer from low throughput in the traditional SUS algorithm, this paper proposed a mechanism called ‘inverse selection’, which is derived from the analysis of the MMSE receiver. The simulation results show that the new algorithm largely improves the throughput of users with poor SINR at a reasonable cost of the overall throughput decrease, thus achieving a profitable tradeoff between system throughput and user fairness. References | Related Articles | Metrics

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Optimal Design for Analog Integrated Circuits Based on ShortChannel Models via Geometric Programming LI Dan, RONG Meng-Tian, SHU Guo-Hua 2011, 45 (03):  354-0357.  Abstract ( 4581 )   Save A method of applying geometric programming to complementary metal oxide semiconductor (CMOS) based on shortchannel models is described. An original solution based on Level 1 model via geometric programming is obtained first. Then simulate the original circuit by Hspice and acquire important parameters of all CMOS transistors from the output list file. These parameters are used in adjusting software to search the adjusting factors and achieve a new solution near the previous one. Simulating and geometric programming iteratively until the objective of optimization keeps stable.  A simulation example proves the algorithm is effective in shortchannel techniques. References | Related Articles | Metrics

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ClosedForm BER Analysis of DSUWB Systems Using Narrowband Interference Suppression Technology GONG Ling-Song, WANG Cheng, YANG Yu-Hang, ZHU Rong-Bo 2011, 45 (03):  358-0362.  Abstract ( 3983 )   Save In order to accurately evaluate the bit error rate(BER) of DSUWB systems with narrowband interference suppressor, a method based on characteristic function (CF) is proposed for precisely calculating the BER of DSUWB systems using twosided transversal filters for rejection of single tone interference. We derive a mathematical expression called interference suppression factor of twosided transversal filters. In addition, theory analyses show that with sufficiently large tap number, the tone interference could be almost cancelled totally. The simulation and numerical results validate the accuracy and effectiveness of analytical BER derivations. References | Related Articles | Metrics

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An Algorithm of Optimizing Throughput in Multi-relay Cooperativ Networks LI Qian-Wen, JIANG Ling-Ge, HE Chen, ZHAN Ao 2011, 45 (03):  363-0367.  Abstract ( 4825 )   Save  This paper considers a wireless network with single sourcedestination pair and multiple potential relays, in which each node accumulates the received information to recover source information, then based on dynamic decode and for ward(DDF) protocol, a relay selection and transmission algorithm is proposed. Firstly, a corresponding mathematical problem of minimizing information’s transmission time is exactly formulated. Moreover, it is proved to be a nondeterministic polynomial complete (NPC ) problem. Secondly, a suboptimal distributed greedy algorithm is proposed, which synthetically considess the chosen relay’s uplink and downlink gains. Not only the chosen relay is ensured to estimate the source information easily but also the network terminal is guaranteed to receive more effective decoding information. Finally, simulation results show that the proposed algorithm almost achieves the optimal network performance. Meanwhile its distributed implement decreases system overhead efficiently. References | Related Articles | Metrics

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The Influence of Formation Manner of Component on Signal Processing Effect of Singular Value Decomposition ZHAO Xue-Zhi, YE Bang-Yan 2011, 45 (03):  368-0374.  Abstract ( 4509 )   Save  Aimed at the formation manner of component signal in singular value decomposition (SVD), the difference of signal processing effect between the simple manner and the average manner was studied. Firstly, for the average manner, a convenient algorithm to get the average of matrix elements is proposed according to the characteristic of Hankel matrix. Secondly, it is proved that the original signal can be decomposed into the linear sum of a series of component signals by SVD with both manners, and a parameter called loss ratio is proposed to evaluate the signal processing effect of both manners. The studying results show that for sine signals, there is no difference between the processing effects of the two manners, while for frequency change signals, the average manner has the advantage of the simple one, however, both manners have extracted the modulated signal caused by the damage in roll track from the complicated vibration signal of a bearing, but the computation amount of the average manner is much larger than that of the simple one. It is recommended that except frequency change signal, for other common signals the simple method should be prior used. References | Related Articles | Metrics

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Robust Vector Precoding with Imperfect Channel State Information Shi-Qi-Ming, JIANG Ling-Ge, HE Chen 2011, 45 (03):  375-0378.  Abstract ( 3941 )   Save A robust vector precoding scheme is proposed for imperfect channel in multiuser MIMO system. In the nonideal channel model, the transmit side only knows imperfect channel state information, i.e. the mean value of the channel estimation and the 1st and the 2nd order statistic value of the estimation error. Based on this channel model, the robust VP precoding matrix and perturbation vector are obtained by minimizing the mean square error of the transmitted and received signals. Simulation results show that the new precoding scheme outperforms the conventional scheme. References | Related Articles | Metrics

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A Multiuser Scheduling Algorithm for MIMO Broadcast Channels with Limited Feedback LI Jun-Fei, YU Hui, LUO Han-Wen, DING Ming 2011, 45 (03):  379-0382.  Abstract ( 4402 )   Save This paper addresses the issue of multiuser scheduling with limited feedback in MIMO broadcast channels. A new user selection algorithm was proposed. In order to exploit multiuser diversity, users feedback the estimation of the available transmit rates as well as the channel directional information. At first, the transmitter divides all the codewords into groups according to their crosscorrelation coefficients. When scheduling, the users are assigned to different groups corresponding to different code regions and then the active user group is selected among the groups. Simulation results show that the presented algorithm can achieve good sumrate performance and obtain the optimal multiuser diversity, with low computational complexity. References | Related Articles | Metrics

Automation Technique, Computer Technology

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Adaptive Consensus Fusion Estimation for Mobile Sensor Networks Wang-Lin, ZHANG Guo-Zhong, ZHU Hua-Yong, SHEN Lin-Cheng 2011, 45 (03):  383-0387.  Abstract ( 4513 )   Save To the problem of distributed estimation for mobile sensor networks（MSN）with communication delays and switching network topologies, a novel distributed fusion estimation algorithm, named adaptive consensus based bistributed unscented information filter（AC_DUIF）, was presented. The proposed algorithm was based on unscented information filter, adaptive consensus algorithm, as well as a new fusion framework for the consideration of the communication delays. An application of target tracking using an air mobile sensor networks with dynamically switched network topologies was employed to illustrate the performance of the proposed algorithm. The simulation results show that the proposed method can significantly improve the accuracy of target position estimation of each sensor node in a distributed fashion, when the distributed consensus between each nodes and the adaptability of the communication delays are assured. References | Related Articles | Metrics

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A SINS Coning Compensation Algorithm Based  on Gyro Error PostCompensation LI Zong-Tao-a, b , WU Tie-Jun-b, MA Long-Hua-b 2011, 45 (03):  388-0392.  Abstract ( 5236 )   Save  The coning compensation computation in strapdown inertial navigation system(SINS) attitude updating algorithms is based on the use of compensated gyros incremental angle outputs,  the gyro output errors compensation has to be performed at the high rate of gyro output sampling,thus increasing the throughout of the navigation compater. A postcompensation algorithm was proposed to solve this problem by calculating the coning compensation with uncompensated gyros incremental angle outputs and then compensating for gyros output errors at the updating rate of coning compensation that is lower than the gyro output sampling rate. The simulation results show that the coning compensation accuracy of the proposed postcompensation algorithm is almost the same as that of traditional precompensation algorithms, but the throughput of the navigation computer is significantly reduced. References | Related Articles | Metrics

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Research of Sliding Mode Controller for Flight Simulator Based  on Disturbance Observer LIU Xiao-Dong, WU Yun-Jie, TIAN Da-Peng, WANG Jun-Feng 2011, 45 (03):  393-397.  Abstract ( 5056 )   Save Because disturbance observer (DOB) underestimates the equivalent disturbances in flight simulator system, one sliding mode variable structure controller (SMVSC) based on DOB was proposed. The controller introduces additional compensation for disturbances, velocity and acceleration of tracking signals, and a new sliding approach law for the SMVSC was defined, then the system meets the conditions for the existence of generalized sliding mode. The experiments on one singleaxis flight simulator show that the proposed control scheme improves the tracking performance with more robustness against parameter uncertainty and extern disturbance, contrasted with the traditional PD+DOB scheme. References | Related Articles | Metrics

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Algorithm for Relative Position and Attitude of  RVD Based on Dualquaternion ZHANG Ze, DUAN Guang-Ren, SUN Yong 2011, 45 (03):  398-402.  Abstract ( 4210 )   Save Traditional algorithm for the determination of relative position and attitude between target spacecraft and tracking spacecraft of RVD is to obtain the direction cosine matrix and translation vector respectively, but this method can not hold the integrity of the rigid body motion, and also, the solving speed and convergence influence the realtime characteristic and the accuracy of the measurement. This paper proposed a new algorithm based on dualquaternion to overcome the disadvantage of the traditional method. The integrity of the relative rotation and translation between the two coordinates is considered. At last, the simulation results show the effectiveness of the new algorithm. References | Related Articles | Metrics

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Sliding Mode Variable Structure Control Based  on Multimodel Online Identification DUAN Chao-Yang, ZHANG Yan, SHAO Lei, LEI Hu-Min, CHEN Zong-Ji 2011, 45 (03):  403-407.  Abstract ( 3717 )   Save  In order to improve the control effect of traditional sliding mode variable structure control system for nonlinear uncertain systems, a new control scheme was proposed, which combines the multimodel online identification with sliding mode variable structure. Firstly, based on the inputoutput data, multiple local models was constructed by online clustering, and the local models are updated. Then, the model of the nonlinear system is given by the combination of all weighted local models. Finally, a sliding mode controller based on reaching law is designed according to the online indentificated system model. The simulation results show the robustness of the proposed scheme to the uncertainty of system model. References | Related Articles | Metrics

Atomic Energy Technology

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RELAP Simulation on the Nonheating Experiment under the External Reactor Vessel Cooling Condition LI Yong-Chun, ZHOU Wei-Hua, YANG Yan-Hua, KUANG Bo, CHENG Xu 2011, 45 (03):  408-412.  Abstract ( 3737 )   Save To study the two phase flow boiling phenomena under external reactor vessel cooling （ERVC）condition, the RELAP code was used to simulate the REPEC nonheating experiment. The simulation is mainly focused on the effect of air flow rate, injection distribution and inlet/outlet area on the natural circulation mass flow velocity and flow phenomena. A good agreement is achieved between the simulation results and experimental data. The natural circulation flow velocity increases with the increasing of air flow rate first and then decreases gradually. The mass flow velocity increases when enlarging the inlet/outlet areas. The flow velocity and flow stability are more sensitive to the outlet area. References | Related Articles | Metrics

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Calculation of HighPrecision Pseudocritical Temperatures for Transcritical Transient Analysis FU Sheng-Wei, ZHOU Chong, YANG Yan-Hua, CHENG Xu 2011, 45 (03):  413-417.  Abstract ( 4462 )   Save The development of thermalhydraulic system code applicable for transcritical transients’ calculation requires the support of a pseudocritical temperature calculating module with high precision. Based on the accurate data of pseudocritical temperatures obtained by the IAPWSIF97 thermalphysical property equations, the relation between pseudocritical temperature and pressure was fitted. The fitting equations are capable of providing pseudocritical temperatures with good precision. This paper presented the implementation of the fitting equations into a thermalhydraulic system code, as well as simulation of some simple transcritical transients. The results indicate that the pseudocritical temperature calculating method developed in this paper is applicable. References | Related Articles | Metrics

Aeronautics & Astronautics

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Robust Autopilot Design for Airtoair Missile Using μ Synthesis ZHANG Min, CHEN Xin, LU Yu-Ping, ZANG Yue-Jin 2011, 45 (03):  418-422.  Abstract ( 4687 )   Save In missile autopilot design process, parameter uncertainties, unmodeled dynamics and external disturbances can be considered by using μ synthesis, so better robustness can be achieved, while using traditional classical controller, it can only do robustness validation. Compared to other robust control theory, both robust stability and robust performance can be designed by using μ synthesis. In this paper, the uncertainty and disturbance model were built, the three channels robust autopilot control law for an example missile was designed, including coupling effect of each channel. The simulations show that the control system meets the requirements of control performances and reaches good robustness. References | Related Articles | Metrics

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Non-fragile Optimal H2/LQR Control with Regional Pole Placement for Hypersonic Vehicle HUANG Yi-Qing, WANG Li, SUN Chang-Yin 2011, 45 (03):  423-428.  Abstract ( 4312 )   Save A kind of robust mixed nonfragile optimal H2/LQR control with regional pole placement was proposed for an airbreathing hypersonic vehicle (AHV). A new linear uncertain model was developed according to a nonlinear longitudinal model of an AHV and then  a multiobjective nonfragile controller was designed that includes regional pole placement, robust guaranteed cost control and optimal H2 control performance indexes for the proposed linear uncertain model. The paper also took the gain variation of the controller into account due to parametric uncertainties of an AHV flight condition and the errors  existed in modeling. The existed conditions of the multiobjective nonfragile controller were deduction by linear matrix inequalities (LMIs). Finally, the simulation comparisons between nonfragile controller and traditional controller that without considering the gain variation illustrate the advantages and effectiveness of our approach. References | Related Articles | Metrics

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Retarded Motion in Approach and Glide Speed Measurement  with TwoStations for Carrier Aircraft YU Tao 2011, 45 (03):  429-432.  Abstract ( 3817 )   Save The motion law in approach for carrier aircraft was analyzed by applying Doppler shift. When carrier aircraft is in uniform glide motion, the proportional navigation guidance law can be derived according to the condition that Doppler changing rate tends towards zero. Then, the retarded motion at equal proportion is emphatically researched and the conclusion is obtained that adjacent Doppler changing rate tends to equal. Based on the fact that the approach for carrier aircraft must be practically a retarded motion, this paper presented an engineering solution detecting glide angle and velocity of carrier aircraft in mobile platform. As opposed to the available multistation measurement mode, the analytic equation of velocity vector of carrier aircraft from Doppler shift equation can be directly derived making use of angle transformation introduced by directionfinding although the location parameter is unknown. The analog calculation verifies that the derived formula of velocity vector is errorless. The error analysis shows that the measuring error of velocity vector is less than 0.1 m/s if the rms value of measurement error of the velocity for aircraft carrier is less than 0.1 m/s. References | Related Articles | Metrics

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Autonomous Orbit Determination of Satellite Navigation System Based on Unscented Kalman Filter ZHAO Xiao-Fang, LIU Sheng-Gang, HAN Chao 2011, 45 (03):  433-438.  Abstract ( 4177 )   Save In accordance with the highly nonlinear of orbit dynamics and the precision requirement of the autonomous orbit determination for navigation constellation, a parallel autonomous orbit determination method based on the dual direction range measurement was proposed. In this method, the unscented Kalman filter is used as the onboard estimation algorithm for each satellite to get its own state and the extra covariance used in this filter which is introduced by the priori orbit is given to ensure the filter stability. The simulation results show that the new method can maintain the long term autonomous orbit determination and the precision of the satellite orbits. References | Related Articles | Metrics