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 t...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.展开更多
Surface Penetrating Radar (SPR) is a recently developed technology for non-destructive testing. It can be used to image and interpret the inner structure of the reinforced concrete. This paper gives the details about ...Surface Penetrating Radar (SPR) is a recently developed technology for non-destructive testing. It can be used to image and interpret the inner structure of the reinforced concrete. This paper gives the details about a compact and handheld SPR developed recently for reinforced concrete structure detection. The center operation frequency of the radar is 1.6 GHz. Not only it has fast acquisition ability, but also it can display the testing result on the LCD screen in real-time. The testing results show that the radar has a penetrating range of more than 30 cm, and a lateral resolution better than 5 cm. The performance validates that the radar can meet the application requirements for reinforced concrete structure detection.展开更多
A kind of architecture of Time-to-Digital Converter(TDC) for Ultra-WideBand(UWB) application is presented. The proposed TDC is based on pulse shrinking, and implemented in a Field Programmable Gate Array(FPGA) device....A kind of architecture of Time-to-Digital Converter(TDC) for Ultra-WideBand(UWB) application is presented. The proposed TDC is based on pulse shrinking, and implemented in a Field Programmable Gate Array(FPGA) device. The pulse shrinking is realized in a loop containing two Programmable Delay Lines(PDLs) or a two-channel PDL. One line(channel) delays the rising edge and the other line(channel) delays the falling edge of a circulating pulse. Delay resolution of PDL is converted into a digital output code under known conditions of pulse width. This delay resolution measurement mechanism is different from the conventional time interval measurement mechanism based on pulse shrinking of conversion of unknown pulse width into a digital output code. This mechanism automatically avoids the influence of unwanted pulse shrinking by any circuit element apart from the lines. The achieved relative errors for four PDLs are within 0.80%–1.60%.展开更多
The basic theory and principle of the artificial Controlled Source Radio Magneto Telluric(CSRMT) method is studied and a novel CSRMT transmitter in kH z frequency band is designed. The specific circuit and measured re...The basic theory and principle of the artificial Controlled Source Radio Magneto Telluric(CSRMT) method is studied and a novel CSRMT transmitter in kH z frequency band is designed. The specific circuit and measured results of some key modules in transmitter are presented, and some outdoor experimental tests have been carried out, which shows that the completed prototype of transmitter can generate a continuous sine current with frequency up to 35.33 k Hz, peak-to-peak amplitude up to 40 A, and realize a reliable transmitting mode with multi-frequency and high-current. The transmitter has a wide operating band, large magnetic moment and high waveform fidelity, and can meet the requirements of shallow geological exploration with high-resolution.展开更多
In this paper,an Ultra-Wideband(UWB) planar antenna is proposed for the reinforced concrete detection,which consists of a pair of planar waterdrop arms,a microstrip to coplanar parallel-strips transition and a shallow...In this paper,an Ultra-Wideband(UWB) planar antenna is proposed for the reinforced concrete detection,which consists of a pair of planar waterdrop arms,a microstrip to coplanar parallel-strips transition and a shallow rectangular cavity.In order to overcome the disadvantages of the shallow cavity,some absorbing material is loaded to weaken the narrow-band effect of the cavity and the crosstalk interference.The simulated and measured results show that the proposed antenna has a large bandwidth from 0.48 GHz to 3.6 GHz with Voltage Standing Wave Ratio(VSWR) below 2 and a fractional bandwidth about 200% under the center frequency of 1.6 GHz,directional radiation characteristics and small late-time ringing in the time domain,which can be suitable for nondestructive detection of the reinforced concrete.展开更多
A novel low-cost 4-element planar array antenna directly fed by a coaxial cable for Ultra-WideBand(UWB) application is presented. The proposed antenna consists of 2×2 bowtie elements and a simple 1:4 power divide...A novel low-cost 4-element planar array antenna directly fed by a coaxial cable for Ultra-WideBand(UWB) application is presented. The proposed antenna consists of 2×2 bowtie elements and a simple 1:4 power divider feeding network. Compared to the basic bowtie element, the impedance bandwidth of the array antenna has a significant improvement that the low cut-off frequency is extended from 6 GHz of the bowtie element to 2 GHz. The measured results show that the proposed antenna has a large bandwidth of 2 GHz to 11 GHz for Voltage Standing Wave Ratio(VSWR)<2, and exhibits a bidirectional radiation pattern and a modest gain across the operating band and a peak gain of about 9 dBi at 11 GHz.展开更多
A simple Ultra-WideBand(UWB)exponentially-tapered Transverse ElectroMagnetic(TEM)horn antenna is presented for the asphalt detection based on Ground Penetrating Radar(GPR).In order to reduce the reflections from the a...A simple Ultra-WideBand(UWB)exponentially-tapered Transverse ElectroMagnetic(TEM)horn antenna is presented for the asphalt detection based on Ground Penetrating Radar(GPR).In order to reduce the reflections from the antenna aperture,some absorbing material is loaded on the outer surface of the conductor.Comparing with the traditional TEM horn antenna,the proposed antenna has a small size and a large impedance bandwidth.Simulated and measured results show that the proposed TEM horn antenna has a low Voltage Standing Wave Ratio(VSWR)below 2 over the whole band from 0.35 GHz to 12 GHz,good radiation characteristics,and small late-time ringing,which can perfectly meet the requirements of the GPR application.展开更多
Calculations of the ElectroMagnetic(EM) response produced by a large horizontal loop placed over layered medium are rather complex because its integral expression contains the product of two Bessel functions and has a...Calculations of the ElectroMagnetic(EM) response produced by a large horizontal loop placed over layered medium are rather complex because its integral expression contains the product of two Bessel functions and has a divergent term. In this paper, an improved fast Hankel and Gaver-Stehfest transforms are introduced to solve the strong-oscillation and slow-decay properties of the integrand, where one Bessel function in the product is substituted by a carefully chosen polynomial of high accuracy and the other used as the digital filter coefficients in the convolution integral. Comparisons prove the validity and the efficiency of the proposed method.展开更多
Discriminating internal layers by radio echo sounding is important in analyzing the thickness and ice deposits in the Antarctic ice sheet.The signal processing method of synthesis aperture radar(SAR)has been widely us...Discriminating internal layers by radio echo sounding is important in analyzing the thickness and ice deposits in the Antarctic ice sheet.The signal processing method of synthesis aperture radar(SAR)has been widely used for improving the signal to noise ratio(SNR)and discriminating internal layers by radio echo sounding data of ice sheets.This method is not efficient when we use edge detection operators to obtain accurate information of the layers,especially the ice-bed interface.This paper presents a new image processing method via a combined robust principal component analysis-total variation(RPCA-TV)approach for discriminating internal layers of ice sheets by radio echo sounding data.The RPCA-based method is adopted to project the high-dimensional observations to low-dimensional subspace structure to accelerate the operation of the TV-based method,which is used to discriminate the internal layers.The efficiency of the presented method has been tested on simulation data and the dataset of the Institute of Electronics,Chinese Academy of Sciences,collected during CHINARE 28.The results show that the new method is more efficient than the previous method in discriminating internal layers of ice sheets by radio echo sounding data.展开更多
基金Supported by the 863 National High Technology Research and Development Program(No.2012AA121901)
文摘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.
文摘Surface Penetrating Radar (SPR) is a recently developed technology for non-destructive testing. It can be used to image and interpret the inner structure of the reinforced concrete. This paper gives the details about a compact and handheld SPR developed recently for reinforced concrete structure detection. The center operation frequency of the radar is 1.6 GHz. Not only it has fast acquisition ability, but also it can display the testing result on the LCD screen in real-time. The testing results show that the radar has a penetrating range of more than 30 cm, and a lateral resolution better than 5 cm. The performance validates that the radar can meet the application requirements for reinforced concrete structure detection.
基金Supported by the National High Technology Research and Development Program(No.2012AA121901)
文摘A kind of architecture of Time-to-Digital Converter(TDC) for Ultra-WideBand(UWB) application is presented. The proposed TDC is based on pulse shrinking, and implemented in a Field Programmable Gate Array(FPGA) device. The pulse shrinking is realized in a loop containing two Programmable Delay Lines(PDLs) or a two-channel PDL. One line(channel) delays the rising edge and the other line(channel) delays the falling edge of a circulating pulse. Delay resolution of PDL is converted into a digital output code under known conditions of pulse width. This delay resolution measurement mechanism is different from the conventional time interval measurement mechanism based on pulse shrinking of conversion of unknown pulse width into a digital output code. This mechanism automatically avoids the influence of unwanted pulse shrinking by any circuit element apart from the lines. The achieved relative errors for four PDLs are within 0.80%–1.60%.
文摘The basic theory and principle of the artificial Controlled Source Radio Magneto Telluric(CSRMT) method is studied and a novel CSRMT transmitter in kH z frequency band is designed. The specific circuit and measured results of some key modules in transmitter are presented, and some outdoor experimental tests have been carried out, which shows that the completed prototype of transmitter can generate a continuous sine current with frequency up to 35.33 k Hz, peak-to-peak amplitude up to 40 A, and realize a reliable transmitting mode with multi-frequency and high-current. The transmitter has a wide operating band, large magnetic moment and high waveform fidelity, and can meet the requirements of shallow geological exploration with high-resolution.
基金Supported by the National High Technology Research and Development Program(No.2012AA061403)
文摘In this paper,an Ultra-Wideband(UWB) planar antenna is proposed for the reinforced concrete detection,which consists of a pair of planar waterdrop arms,a microstrip to coplanar parallel-strips transition and a shallow rectangular cavity.In order to overcome the disadvantages of the shallow cavity,some absorbing material is loaded to weaken the narrow-band effect of the cavity and the crosstalk interference.The simulated and measured results show that the proposed antenna has a large bandwidth from 0.48 GHz to 3.6 GHz with Voltage Standing Wave Ratio(VSWR) below 2 and a fractional bandwidth about 200% under the center frequency of 1.6 GHz,directional radiation characteristics and small late-time ringing in the time domain,which can be suitable for nondestructive detection of the reinforced concrete.
基金Supported by the National High Technology Research and Development Program(No.2012AA121901)
文摘A novel low-cost 4-element planar array antenna directly fed by a coaxial cable for Ultra-WideBand(UWB) application is presented. The proposed antenna consists of 2×2 bowtie elements and a simple 1:4 power divider feeding network. Compared to the basic bowtie element, the impedance bandwidth of the array antenna has a significant improvement that the low cut-off frequency is extended from 6 GHz of the bowtie element to 2 GHz. The measured results show that the proposed antenna has a large bandwidth of 2 GHz to 11 GHz for Voltage Standing Wave Ratio(VSWR)<2, and exhibits a bidirectional radiation pattern and a modest gain across the operating band and a peak gain of about 9 dBi at 11 GHz.
基金Supported by the National High Technology Research and Development Program(No.2012AA121901)
文摘A simple Ultra-WideBand(UWB)exponentially-tapered Transverse ElectroMagnetic(TEM)horn antenna is presented for the asphalt detection based on Ground Penetrating Radar(GPR).In order to reduce the reflections from the antenna aperture,some absorbing material is loaded on the outer surface of the conductor.Comparing with the traditional TEM horn antenna,the proposed antenna has a small size and a large impedance bandwidth.Simulated and measured results show that the proposed TEM horn antenna has a low Voltage Standing Wave Ratio(VSWR)below 2 over the whole band from 0.35 GHz to 12 GHz,good radiation characteristics,and small late-time ringing,which can perfectly meet the requirements of the GPR application.
基金Supported by Chinese Government SinoProbe Plan(No.SinoProbe-09-02)R&D of Key Instruments and Technologies for Deep Resources Prospecting(No.ZDYZ 2012-1-03)
文摘Calculations of the ElectroMagnetic(EM) response produced by a large horizontal loop placed over layered medium are rather complex because its integral expression contains the product of two Bessel functions and has a divergent term. In this paper, an improved fast Hankel and Gaver-Stehfest transforms are introduced to solve the strong-oscillation and slow-decay properties of the integrand, where one Bessel function in the product is substituted by a carefully chosen polynomial of high accuracy and the other used as the digital filter coefficients in the convolution integral. Comparisons prove the validity and the efficiency of the proposed method.
基金supported by the National Hi-Tech Research and Development Program of China("863"Project)(Grant No.2011AA040202)the National Natural Science Foundation of China(Grant No.40976114)
文摘Discriminating internal layers by radio echo sounding is important in analyzing the thickness and ice deposits in the Antarctic ice sheet.The signal processing method of synthesis aperture radar(SAR)has been widely used for improving the signal to noise ratio(SNR)and discriminating internal layers by radio echo sounding data of ice sheets.This method is not efficient when we use edge detection operators to obtain accurate information of the layers,especially the ice-bed interface.This paper presents a new image processing method via a combined robust principal component analysis-total variation(RPCA-TV)approach for discriminating internal layers of ice sheets by radio echo sounding data.The RPCA-based method is adopted to project the high-dimensional observations to low-dimensional subspace structure to accelerate the operation of the TV-based method,which is used to discriminate the internal layers.The efficiency of the presented method has been tested on simulation data and the dataset of the Institute of Electronics,Chinese Academy of Sciences,collected during CHINARE 28.The results show that the new method is more efficient than the previous method in discriminating internal layers of ice sheets by radio echo sounding data.
