• Volume 8,Issue 3,2010 Table of Contents
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    • Design and implementation of high speed and general-purpose digital modulator

      2010, 8(3):247-250.

      Abstract (12738) HTML (0) PDF 471.65 K (10832) Comment (0) Favorites

      Abstract:This article introduces a new type of high speed,multi-modulated digital modulator with adjustable center frequency and bit rate features. It can realize the Quadrature Phase Shift Keying(QPSK) and 16QAM(Quadrature Amplitude Modulation) with 80 MHz center frequency and 7.936 5 MHz bandwidth. The general-purpose modulation arithmetic based on software radio,symbol mapping and the realization of pulse shaping filter are discussed. The measuring results demonstrate that the modulation scheme meets the requirements of practicability and general utilization.

    • Adaptive selective combining Hybrid ARQ based on RCPT codes

      2010, 8(3):251-256.

      Abstract (6011) HTML (0) PDF 489.56 K (4989) Comment (0) Favorites

      Abstract:Hybrid Automatic Repeat reQuest(Hybrid ARQ) which is an excellent error control technique has been accepted as a key technique of 3GPP Long Term Evolution(LTE). Hybrid ARQ scheme based on Rate Compatible Punctured Turbo(RCPT) codes has outstanding performance and low implementation complexity, therefore this scheme has attracted wide concern. Traditional Hybrid ARQ schemes consist of Chase Combining based Hybrid ARQ(CC-HARQ) which has greater performance gain under higher channel SNR; and IR(Incremental Redundancy) based Hybrid ARQ which provides precise rate control under lower channel SNR. This paper proposes an Adaptive Selective Combining Hybrid ARQ(ASC-HARQ) which adaptively chooses CC-HARQ or IR-HARQ according to different channel SNR, while the receiver adaptively combines selected code blocks with high reliability. This paper analyzes the scheme’s performance in Rayleigh fading channel. Simulation results are given to compare the performance of this novel scheme with that of CC-HARQ and IR-HARQ. According to the simulation results, this scheme performs better than traditional schemes with similar complexity.

    • Location estimation based on CC2431 RF transceiver in WSN

      2010, 8(3):257-260.

      Abstract (12307) HTML (0) PDF 353.14 K (6924) Comment (0) Favorites

      Abstract:The location estimation in Wireless Sensor Networks(WSN) has been widely discussed in this field recently. This study introduced the location methods that were commonly used in IEEE 802.15.4 network and summarized the main sources of error in Received Signal Strength Indication(RSSI) based location estimation, combined with the approaches to improve location accuracy. The use of the location engine implemented in the CC2431 to estimate location was mainly discussed. The practical measurement results of location were given to prove that the CC2431 had met the application requirements. And all the performance criteria of the location system were analyzed.

    • A method for producing dense false-signal

      2010, 8(3):261-264.

      Abstract (6173) HTML (0) PDF 419.57 K (4027) Comment (0) Favorites

      Abstract:Dense false-target jamming can implement effective blanket jamming on radar. This kind of jamming can make radar too busy to process true target, even bring on the saturation of radar signal processing. Time-delay and overlap-add techniques or convolution technique can produce dense false-signal, nevertheless they consume more resource. A new method for producing dense false-signal— compartmentalization and regroupment is proposed in the paper. This method does not include multiplication operation that needs more time and storage. It is related only to pulse width and has nothing to do with the number of false targets. Simulation and experiment results have proved the validity of this method.

    • Technology of track deception for cooperative control of multiple

      2010, 8(3):265-268.

      Abstract (5744) HTML (0) PDF 354.55 K (4493) Comment (0) Favorites

      Abstract:With the extensive application of data fusion technology,it is quite easy for the network of radars to identify track deception against single radar. The stealthy Electronic Combat Air Vehicles(ECAV) equipped with Electronic Counter Measures(ECM) can deceive a radar by using range delay deception technique. This make the radar detect a fake target called phantom beyond the ECAV location. Phantom track is generated by using sequential location of phantom. The important feature of generating phantom track is its kinematic and dynamic constraints. These constraints restrict the freedom of phantom. This paper presents a technology used by the cooperative control of a team of ECAV to deceive network of radars through the generation of a space-time coherent phantom track.The equation of motion and the constraints of the phantom are given. Some approaches to solve the technical problems are described. Simulation results of the optimal control algorithm prove the feasibility and practicability of this method.

    • Design and implementation of azimuth-recording system

      2010, 8(3):269-272.

      Abstract (4768) HTML (0) PDF 463.33 K (3656) Comment (0) Favorites

      Abstract:The azimuth-recording system can affect the measuring precision of radar directly. To realize the auto recording about azimuth of antenna exported by various angle sensors, a multifunctional azimuth-recording system was designed. The measuring elements of angle sensor, the structural composition of multifunctional azimuth-processing unit and the working principle of north-finder, were discussed. The primary hardware of this system and the flow of data fusion were described in detail. It was proved by practical application that the accuracy of this system was sufficient for radar precision.

    • Programming analysis of the quasi-Yagi antenna by using FDTD method

      2010, 8(3):273-275.

      Abstract (6245) HTML (0) PDF 386.53 K (4167) Comment (0) Favorites

      Abstract:The Finite Difference Time Domain(FDTD) method was used to calculate the Voltage Standing Wave Ratio(VSWR) of a quasi-Yagi antenna. The model of the antenna was created and the mesh was generated by using model describing file. To simplify the calculating program, a Uniaxial anisotropic Perfectly Matched Layer(UPML) region was divided into six sub-regions and sub-regional symmetry was taken into account. The voltage source with lumped resistance was as excitation in the program. At last, VSWR was obtained by separating input voltage from total. A prototype quasi-Yagi antenna was fabricated and measured. The simulation result approximated to the measurement result, which proved the method had been correct.

    • Design and optimization of compact AES as stream cipher in radar system

      2010, 8(3):276-280.

      Abstract (4675) HTML (0) PDF 502.98 K (4377) Comment (0) Favorites

      Abstract:In order to satisfy the encryption requirements of radar system data transfer, the Counter (CTR) mode of Advanced Encryption Standard(AES) was modified into a stream cipher. Through structure folding and module reuse, the resource utilization was reduced and the throughput was increased. In Spartan3 FPGA, 276.53 Mbps throughput could be achieved only by using 728 slices. The resource-saving pure logic mode and high-speed distributed memory mode were implemented in the design. On-the-fly key scheduling and pipeline were also performed, which led to high throughput and security level. The real-life test showed the design had satisfied the requirements of radar signal encryption, which revealed a great potential of stream mode AES in radar signal transmission.

    • Multilevel data simulation of the interferometric Synthetic Aperture Radar

      2010, 8(3):281-285.

      Abstract (6020) HTML (0) PDF 842.55 K (4061) Comment (0) Favorites

      Abstract:In order to provide the data source for the research of Interferometric Synthetic Aperture Radar(InSAR) system,a novel InSAR simulator was studied,which consisted of the Raw Signal Level (RSL),the Single-look-complex Image Level(SIL),and the Interferometric Phase Level(IPL). This simulator could be applied to the Synthetic Aperture Radar(SAR)/InSAR data simulation of both spaceborne and airborne. A new model of complex backscattering coefficients for the InSAR data simulation was presented and validated. Furthermore the implementation details of the multilevel simulator were discussed. For the RSL,a new model with higher computation efficiency to generate the radar echo was proposed,benefitting from the symmetry of the signal generation,the multi-core technique of CPU and many-core technique of Graphic Processing Units(GPU). For the image level,an efficient approach to create single-look image pair was presented. For the IPL,a reasonable noise model related to geometric decorrelation was also proposed. Some meaningful results by the novel simulator verified the theoretical analysis.

    • Quantitative study on the selection of wavelet functions for the de-noising of ECG signal

      2010, 8(3):286-289.

      Abstract (5005) HTML (0) PDF 279.76 K (4570) Comment (0) Favorites

      Abstract:To quantitatively evaluate the de-noising effects of different wavelet functions on the electrocardiogram(ECG) signal,a noisy ECG model was constructed as an experimental standard signal,which was processed by orthogonal wavelet transform and different thresholding methods to remove high-frequency noise. The de-noising effects were measured by Signal to Noise Ratio(SNR) and the shape of waveforms. It was demonstrated that when the SNR after denoising approached to that of the standard signal,the de-noising effect was optimal. Thus,the de-noising schemes with the less signal distortion and the higher SNR were obtained. Meanwhile,the wavelet function appropriate for the decomposition and reconstruction of ECG signal was determined. Verified by MIT-BIH database,the results of this study can effectively remove high-frequency noise in ECG signal.

    • Identification of lunar subsurface echoes from radar sounder echoes with strong background surface off-nadir clutters

      2010, 8(3):290-296.

      Abstract (4871) HTML (0) PDF 1.09 M (3781) Comment (0) Favorites

      Abstract:An effective approach for subsurface echo extraction was developed on the basis of the coherent and incoherent characteristics of the subsurface nadir echoes and surface off-nadir echoes (clutter). By stacking and averaging the received radar sounder echoes at different time series,subsurface echo could be identified if the subsurface topography variation was not too large. Taking the simulated radar sounder echoes from lunar maria and highlands area as example,this study verified the feasibility of this approach numerically. Finally,the influence on subsurface echo identification by the stacking number and surface roughness was discussed. The approach in this paper can be applied to Martian and other planetary exploration.

    • Geometric distortion correction in the circular scanning SAR imaging processing

      2010, 8(3):297-302.

      Abstract (5090) HTML (0) PDF 614.68 K (4034) Comment (0) Favorites

      Abstract:Circular scanning Synthetic Aperture Radar(SAR) works in beam-scan mode,whose radar antenna conically scans with respect to the vertical direction,so that the images of full circular area around the radar platform can be formed. The geometric distortion correction of the images processed by an airborne circular scanning SAR was investigated. While the radar antenna was scanning,the imaging geometry also changed with time. After discussing the mechanism of geometric distortion,a method of geometric distortion correction based on geographic coordinate of subimage’s pixel was put forward. Live data processing validated the method proposed,and SAR image without geometric distortion was obtained.

    • Noise reduction for heart sound based on wavelet transform

      2010, 8(3):303-307.

      Abstract (6012) HTML (0) PDF 606.17 K (5111) Comment (0) Favorites

      Abstract:To compensate for the deficiencies of traditional threshold functions and obtain the heart sound with high SNR for better analysis,a novel threshold function was proposed in this study. The function quantified the detail coefficients of each level of noisy heart sounds effectively through adjusting the values of the parameters a and m. In the simulation, the traditional soft and hard threshold functions and the new threshold function were used in noise reduction for many cases of standard heart sounds respectively and the comparative analysis of the effect of noise reduction was made. The new threshold function was applied to noise reduction of the measured heart sounds as well. The results indicated that the new threshold function could better reserve the characteristics of heart sounds, eliminate noise effectively, and was of strong practical value.

    • DSP implementation of FQPSK/CEFQPSK modulator

      2010, 8(3):308-312.

      Abstract (6126) HTML (0) PDF 373.93 K (3941) Comment (0) Favorites

      Abstract:Feher patented Quadrature Phase Shift Keying(FQPSK),which is suitable for deep space communication,is introduced at first. In order to improve its envelope fluctuation,a modified FQPSK modulation—Constant Envelope FQPSK(CEFQPSK) that has an absolutely constant envelope is presented. This modulation method not only keeps the high bandwidth efficiency, Interference and Jitter Free(IJF) features of FQPSK,but also improves the power efficiency of the radio frequency amplifiers to the utmost. In order to generate signal at high speed and real-time,several optimized technologies are adopted and these two modulation technologies are implemented by using DSP of TI.

    • Design of high-speed data acquisition system based on band-pass sampling

      2010, 8(3):313-317.

      Abstract (10212) HTML (0) PDF 397.43 K (10853) Comment (0) Favorites

      Abstract:High-speed data acquisition system is an important component in modern radar signal processing. A design of high-speed data acquisition system based on band-pass sampling was presented and applied to the signal processing of wideband receiver. The Virtex Series FPGA was used as the main platform to control the high-speed ADC08D1000 for completing data acquisition, transmission,storage and signal processing. High-speed First Input First Output(FIFOs) were selected as the storage devices to implement data rate conversion. The system realized the software and hardware design,and test results verified the feasibility of the solution.

    • HEMP effect experiment for surface 1553B communication system

      2010, 8(3):318-323.

      Abstract (5037) HTML (0) PDF 389.05 K (4102) Comment (0) Favorites

      Abstract:High altitude Electro Magnetic Pulse(HEMP) effect experiments were prosecuted for a surface supervisory control system with a 1553B communication system in order to study the HEMP- resisting capability of surface facility,to explore the key coupling points,and to find a effective hardening method. The electromagnetic coupling ports of entry were analyzed, then examination project according to the coupling ports was designed. The coupling signals on the ports of cable, coupling transformer, and isolation transformer,were tested. The influence of coupling transformer and isolation transformer having on the interference signals were analyzed,the hardening method to reduce HEMP coupling by low-pass filters was validated. The experiment results showed the 1553B communication system was of a better HEMP-resisting capability,the coupling transformer had a strong impact on the coupling signals on the ports of cable,and the low-pass filters would reduce the HEMP coupling level effectively and simply.

    • Development of pulse power supply for X-band TWT experiment

      2010, 8(3):324-327.

      Abstract (5915) HTML (0) PDF 413.66 K (4029) Comment (0) Favorites

      Abstract:The pulse power supply for X-band Traveling-Wave Tube(TWT) experiment was developed. It consisted of anode control power supply,slow-wave line power supply,collector power supply,auxiliary power supply and control system. Since the output pulse width of the anode control power supply had varied greatly,the series-connected Insulated Gate Bipolar Transistors(IGBT) switch was applied to anode control power supply. The experiment results indicated that the power supply system could meet the requirements of the X-band TWT experiment,and the pulse voltage with continuously adjustable pulse width from 4 μs to 3 000 μs had been obtained on the anode of the X-band TWT.

    • Compton effect on X-ray transmission spectrum

      2010, 8(3):328-330.

      Abstract (5717) HTML (0) PDF 443.21 K (5742) Comment (0) Favorites

      Abstract:Shield material with some certain composition can absorb a large part of low energy photon of X-ray and reduce the radiation effect on electronic component. However,in some cases,photon quantity of several low energy bins in transmission spectrum will be larger than that in incidence spectrum due to Compton scattered photons. This is disadvantageous for radiation protection. The study discussed such factors relative to scattered photon impact as source photon energy,the place of detector,the composition and the thickness of shield material. Under several different conditions,X-ray transmission spectra were calculated. The rule of Compton photons affecting on X-ray transmission spectrum was found. Lastly,some countermeasures were put forward.

    • Transmission Wave-front correction of atmospheric optical communication based on adaptive optics technology

      2010, 8(3):331-335.

      Abstract (4189) HTML (0) PDF 382.60 K (4428) Comment (0) Favorites

      Abstract:In order to address the issues such as wave-front distortion,reflection and other phenomena in atmospheric optical communication,which seriously affect the communication quality,the Adaptive Optics(AO) technology was used to reconstruct the distorted wave-front, then reflective mirrors were used to amend the aberrations.Theoretical analysis, simulation and experiments were performed. The result indicated that under the same experimental conditions, as the Bit Error Ratio(BER) of the system kept the value of 1×10-6,the system transmitting power when using adaptive optics technology had been reduced by half than that when not using adaptive optics technology. In the Near-earth atmospheric laser communications, the effects of AO in increasing the system gain and reducing the system bit error rate are significant.

    • Design and implementation of UDP communication simulation testing software based on UML

      2010, 8(3):336-340.

      Abstract (4364) HTML (0) PDF 291.16 K (4234) Comment (0) Favorites

      Abstract:The testing cases or fault of User Datagram Protocol(UDP) communication are difficult to be injected into the testing environment when testing some control and communication software. This paper presents a new approach of building UDP communication simulation testing software using Unified Modeling Language(UML),and introduces the implementation technique of multiple UDP communication software interacting with the software under test. With this simulation testing platform,users can easily input the testing case or fault into the simulation testing environment,moreover,the efficiency and effectiveness of testing are improved.

    • Development of the networked surveillance device for USB peripherals

      2010, 8(3):341-344.

      Abstract (4805) HTML (0) PDF 371.04 K (3631) Comment (0) Favorites

      Abstract:According to the information security management requirements to the USB peripherals, basing on the network client/server model, this study developed a network centralized surveillance device for USB peripherals. Basing on the unique ID of USB peripherals, adopting hub dispatch device to expand USB insert slot, it could obtain and identify every unique mark and status message for each USB peripheral in USB slots by using the inbuilt USB interface store system, then transfer them to remote supervising center by the Ethernet. It built web service functions by using Winsock technology in the controller center. It could supervise the USB interfaces status including lending and returning through the remote monitoring center effectively and in real-time. Moreover, it would give an alarm according to alarm device regulation. This device is of small size, high credibility, easy to be installed. And the centralized supervising of the USB interfaces can be realized through the confidentiality network.

    • Design of universal test equipment of pulse radar altimeter

      2010, 8(3):345-348.

      Abstract (4949) HTML (0) PDF 271.74 K (3664) Comment (0) Favorites

      Abstract:Virtual instrument technology can improve flexibility and expansibility of test system. A design method of universal test equipment for pulse radar altimeter is introduced in this paper. Based on computer and standard instruments,by using Dynamic Link Library(DLL) of standard instruments control built by LabVIEW via Visual C++, the parameters of pulse radar altimeter such as working voltage,transmitting frequency,receiving frequency,movement sensitivity and transmitting power can be tested,displayed,printed and stored. The test results can be queried in the future. By increasing notes in parameter list and upgrading DLL,it is convenient to measure other types of pulse radar altimeter with this test equipment using parametric design and database modeling technology.

    • Part access technology of Web based on script and pass parameters of URL

      2010, 8(3):349-352.

      Abstract (5241) HTML (0) PDF 276.13 K (3927) Comment (0) Favorites

      Abstract:Access control technology is necessary for information security and open Web service. Main access control technology considers the system as a whole and provides the technical platform to implement access control policy. In the view of information security and economic benefit, this article presents part access control technologies according to different demands of Web. Based on the platform of whole access control technology,according to the process of Web browsing,part access control of Web information resource can be realized through script Microsoft Active Server Pages(ASP) access and the pass parameters of Uniform Resource Locator(URL) expressing the attributes of location in database. It can resolve security problems of Web access at a low cost.

    • Design of wireless remote meter reading based on bluetooth and ARM

      2010, 8(3):353-356.

      Abstract (4808) HTML (0) PDF 343.78 K (4018) Comment (0) Favorites

      Abstract:By studying the wireless meter reading system and taking advantages of the bluetooth short-distance communication,this study presented a wireless meter reading system based on bluetooth technology and Advanced RISC Machines(ARM). After analyzing the needs of the wireless meter reading,the overall structure of the system was put forward. Taking CSR's bluetooth chip as the core,bluetooth communication devices were designed. In order to improve the performance of the overall system,ARM processor was adopted as the primary processor in the core components concentrated center of the system. In order to achieve remote data transmission,GPRS modules were used. Through the research focused on the work process,as well as the bluetooth device piconet communications,software design and software flow chart were given. Application results show that the design is efficient,reliable, and provided with good performance,which can offset the deficiencies in existing programs.

    • Dual-host redundancy design on safe control of balloon

      2010, 8(3):357-359.

      Abstract (4944) HTML (0) PDF 251.01 K (3833) Comment (0) Favorites

      Abstract:The floating time of aerostat-load-radar is very long in modern warfare. Therefore the high stable and reliable balloon control system is needed. A design scheme of dual-host redundancy system was put forward,which adopted two host computers working together and the two computers could switch in real time. The scheme was verified through actual project. The balloon can work for several months,which meet the reliability requirements of the balloon control system in aerostat-load-radar.

    • Software design of measure-control system for large tethered balloons

      2010, 8(3):360-363.

      Abstract (4836) HTML (0) PDF 285.16 K (3791) Comment (0) Favorites

      Abstract:A distinct characteristic of large tethered balloons is floating for a long time in the sky, which determines that the measure-control system working steadily and reliably is especially important. Based on the makeup of measure-control system of large tethered balloons and software architecture, some design considerations and engineering realization methods for measure-control software on balloon (including initialization, communication process, data process, balloon control, communication station control and emergency treatment) and display-control software on ground were presented. It is proved that dual redundant design is one effective way to improve the reliability of measure-control systems of tethered balloons by engineering practice.

    • A method to detect the presence of virtual environment in the analysis of malware

      2010, 8(3):364-367.

      Abstract (4772) HTML (0) PDF 260.40 K (4384) Comment (0) Favorites

      Abstract:Security Companies usually apply virtual environment to analyze malware,whereas a large amount of current malware already adopts various VMware detection techniques in order to resist analysis. In this paper,three main methods for detecting the presence of virtual environment are presented,as well as their countermeasures. A performance related method to detect the presence of virtual machine or emulator is designed,which can successfully detect the presence of virtual environment,such as VMware and Qemu,etc.

    • Real-time target tracking on upper computer using CUDA

      2010, 8(3):368-371.

      Abstract (5553) HTML (0) PDF 318.30 K (4270) Comment (0) Favorites

      Abstract:Real-time target tracking on upper computer using CPU will spend much time because of a great amount of calculation,which will affect the tracking. In recent years, nVidia Corporation has put forward a compute architecture called Compute Unified Device Architecture(CUDA) which calculates in parallel using Graphics Processing Units(GPU). This study introduced the architecture and principle of CUDA, then tracked target in real time using this method, and compared the calculating speed of CUDA with that of traditional method. The result showed that CUDA could speed up calculation and be well used in real-time target tracking on upper computer.

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