Geological penetrating radar combined with drilling and chemical analysis has been applied to investigate leakage pollution of Longpan Road gas station in Nanjing, China. The results indicate that radar images show st...Geological penetrating radar combined with drilling and chemical analysis has been applied to investigate leakage pollution of Longpan Road gas station in Nanjing, China. The results indicate that radar images show strong reflection anomalies along the northeast to the gas station, characterized by contaminants or contaminant plumes spreading downstream and below. The drilling results confirmed the contents of monocyclic and polycyclic aromatic hydrocarbons contained in the layers of fine sands ranging from 0.60 m to 6.0 m beneath the surface mostly exceed Chinese standard severely, such as toluene and isobutylbenzene with high content at 2738 μg/kg and 64505 μg/kg, respectively. Therefore, it is considered that geological penetrating radar can be employed to investigate leakage contamination of gas stations, and remediation and administration should be conducted in the polluted soil layers and aquifers.展开更多
Direct quadrature modulation technology is suitable for wide-band radar signal generation. However, this method has rigorous requirements on amplitude and phase balance of the orthogonal input signals. If the requirem...Direct quadrature modulation technology is suitable for wide-band radar signal generation. However, this method has rigorous requirements on amplitude and phase balance of the orthogonal input signals. If the requirements are not satisfied, there would be modulation errors such as image frequency and oscillator leakage that cannot be filtered. The modulation errors will therefore raise the noise floor of the range profile and reduce the dynamic range of the Synthetic Aperture Radar (SAR) image as a whole. In this paper, the wide-band In-phase/Quadrature-phase (I/Q) modulation errors are modeling analyzed, and the influence of wide-band I/Q modulation errors on SAR imaging is discussed. Furthermore, a compensation method of modulation errors is proposed, and the circuit implementation of the radar signal generation and pre-distortion is presented. The experimental results illustrate that the curves of the I/Q amplitude and phase imbalance errors are successfully extracted and the rejection of image frequency improved significantly, thus meets the requirements of the SAR imaging.展开更多
The paper presents a high-resolution automobile Frequency Modulation Continuous Wave Synthetic Aperture Radar(FMCW SAR) named MiniSAR and the procedure of its signal processing.The imaging geometry of automobile SAR i...The paper presents a high-resolution automobile Frequency Modulation Continuous Wave Synthetic Aperture Radar(FMCW SAR) named MiniSAR and the procedure of its signal processing.The imaging geometry of automobile SAR is very different from that of airborne SAR,leading to a different data processing method for automobile SAR.Therefore,in the paper,we propose an image formation approach that can well handle the focusing issues of automobile SAR.The effects of the strong reflected signal and the spatial-variant synthetic aperture length are analyzed.The processed results with automobile FMCW SAR read data validate the presented method.展开更多
文摘Geological penetrating radar combined with drilling and chemical analysis has been applied to investigate leakage pollution of Longpan Road gas station in Nanjing, China. The results indicate that radar images show strong reflection anomalies along the northeast to the gas station, characterized by contaminants or contaminant plumes spreading downstream and below. The drilling results confirmed the contents of monocyclic and polycyclic aromatic hydrocarbons contained in the layers of fine sands ranging from 0.60 m to 6.0 m beneath the surface mostly exceed Chinese standard severely, such as toluene and isobutylbenzene with high content at 2738 μg/kg and 64505 μg/kg, respectively. Therefore, it is considered that geological penetrating radar can be employed to investigate leakage contamination of gas stations, and remediation and administration should be conducted in the polluted soil layers and aquifers.
基金Supported by 863 Program (2009AA12Z103)973 Program (2009CB72400)
文摘Direct quadrature modulation technology is suitable for wide-band radar signal generation. However, this method has rigorous requirements on amplitude and phase balance of the orthogonal input signals. If the requirements are not satisfied, there would be modulation errors such as image frequency and oscillator leakage that cannot be filtered. The modulation errors will therefore raise the noise floor of the range profile and reduce the dynamic range of the Synthetic Aperture Radar (SAR) image as a whole. In this paper, the wide-band In-phase/Quadrature-phase (I/Q) modulation errors are modeling analyzed, and the influence of wide-band I/Q modulation errors on SAR imaging is discussed. Furthermore, a compensation method of modulation errors is proposed, and the circuit implementation of the radar signal generation and pre-distortion is presented. The experimental results illustrate that the curves of the I/Q amplitude and phase imbalance errors are successfully extracted and the rejection of image frequency improved significantly, thus meets the requirements of the SAR imaging.
基金Supported jointly by the Hundred Talents Program of the Chinese Academy of Sciences and General Program of National Natural Science Foundation of China(No.6117212)
文摘The paper presents a high-resolution automobile Frequency Modulation Continuous Wave Synthetic Aperture Radar(FMCW SAR) named MiniSAR and the procedure of its signal processing.The imaging geometry of automobile SAR is very different from that of airborne SAR,leading to a different data processing method for automobile SAR.Therefore,in the paper,we propose an image formation approach that can well handle the focusing issues of automobile SAR.The effects of the strong reflected signal and the spatial-variant synthetic aperture length are analyzed.The processed results with automobile FMCW SAR read data validate the presented method.
