- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Inverse synthetic aperture lidar imaging of indoor real data
摘要： Inverse synthetic aperture imaging lidar is a new active imaging system, which can offer a finer azimuth resolution than that achieved in conventional SAR system and obtain vivid images close to the optical photos. Firstly, the principle of the inverse synthetic aperture techniques is described. Secondly, after analyzing the data of the inverse synthetic aperture imaging lidar, the mathematic model of the data is given. Thirdly, a method, combined with "CLEAN" techniques, is proposed for inverse synthetic aperture imaging lidar processing, which is based on the analysis of data's time-frequency character. The presented method uses the second-order phase of the data in azimuth, estimates the instantaneous Doppler spectrum and obtains the instantaneous images in the range and the instantaneous Doppler domains, which can avoid the defocusing of the images using the range Doppler algorithm and improve the imaging quality. Finally, the data processing of the real data proves the validity of the given method.
关键词： Imaging,Lidar,Time-frequency analyzing,Inverse synthetic aperture
更新于2025-09-23 15:23:52
-
Retrieval of Ionospheric Faraday Rotation Angle in Low-frequency Polarimetric SAR Data
摘要： A low-frequency spaceborne synthetic aperture radar (SAR) working system, e.g., operating at the L-band or P-band, has great advantages of military target detection and biomass monitoring. Nevertheless, it is more susceptible to ionospheric effects compared with the higher frequency system. A trans-ionospheric wave propagation model is established in this paper to incorporate ionospheric effects on SAR signals. As one of the signi?cant distortion sources for the polarimetric SAR (PolSAR), Faraday rotation (FR) is mainly imposed by background ionosphere, and its spatial variation is discussed. FR estimators have been devised in succession to estimate FR angle (FRA), and various potential novel estimators can still be derived. But, from a viewpoint of theoretical expressions, the earliest estimator is bound to be the optimal one. Based on PolSAR real data, this mathematical conclusion is further validated via comprehensive performance analysis as to estimation bias and standard deviation rather than the existent root-mean-square principle. Finally, a step-by-step procedure of the FRA map is proposed and operated with an application of the airborne P-band PolSAR data. In particular, the ambiguity error of FRA estimates within a SAR observation is simulated and resolved. By processing the ALOS-2 real data, the spatial distribution of FRAs is retrieved and used to operate ionospheric total electron content soundings.
关键词： FR angle (FRA) map,ionospheric TEC soundings,Faraday rotation (FR) estimators,Spaceborne synthetic aperture radar (SAR)
更新于2025-09-23 15:23:52
-
[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Moving Target Detection for THz SAR Systems Based on Multilook Processing
摘要： Compared with conventional X-band synthetic aperture radar (SAR) systems, THz SAR is more sensitive to Doppler vibration and has better detection performance for moving targets. In this paper, a moving target detection scheme is designed for terahertz SAR systems based on multilook processing. The Doppler spectrum is divided into several sub-looks and focused separately to generate corresponding sub-images. Moving targets are indicated through sharpness detection of the sub-images. The effectiveness of the proposed algorithm is veri?ed by simulated data.
关键词： terahertz,multilook processing,moving target detection,Synthetic aperture radar
更新于2025-09-23 15:23:52
-
Mapping Two-Dimensional Deformation Field Time-Series of Large Slope by Coupling DInSAR-SBAS with MAI-SBAS
摘要： Mapping deformation field time-series, including vertical and horizontal motions, is vital for landslide monitoring and slope safety assessment. However, the conventional differential synthetic aperture radar interferometry (DInSAR) technique can only detect the displacement component in the satellite-to-ground direction, i.e., line-of-sight (LOS) direction displacement. To overcome this constraint, a new method was developed to obtain the displacement field time series of a slope by coupling DInSAR based small baseline subset approach (DInSAR-SBAS) with multiple-aperture InSAR (MAI) based small baseline subset approach (MAI-SBAS). This novel method has been applied to a set of 11 observations from the phased array type L-band synthetic aperture radar (PALSAR) sensor onboard the advanced land observing satellite (ALOS), spanning from 2007 to 2011, of two large-scale north–south slopes of the largest Asian open-pit mine in the Northeast of China. The retrieved displacement time series showed that the proposed method can detect and measure the large displacements that occurred along the north–south direction, and the gradually changing two-dimensional displacement fields. Moreover, we verified this new method by comparing the displacement results to global positioning system (GPS) measurements.
关键词： synthetic aperture radar,deformation field time-series,open-pit slope,multiple-aperture InSAR,DInSAR
更新于2025-09-23 15:22:29
-
[IEEE 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Macau, Macao (2018.9.26-2018.9.28)] 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Research on Fast Algorithm for General Bistatic SAR Raw Signal
摘要： A fast algorithm for general bistatic synthetic aperture radar (SAR) raw signal based on two-dimensional frequency domain is proposed. The SAR echo signal model is established by the algorithm, the accurate expression of two-dimensional frequency domain for the bistatic SAR echo signal are deduced with series reversion. Simulating large range and azimuth coupling, the accurate computation of echo signal is realized and the complexity of the algorithm is analyzed. The simulation results show that the simulation speed of SAR echo is greatly improved under the premise of ensuring the high phase accuracy, and the validity of the algorithm is proved.
关键词： synthetic aperture radar (SAR),bistatic,series reversion,echo simulation
更新于2025-09-23 15:22:29
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Desnet: Deep Residual Networks for Descalloping of Scansar Images
摘要： Scalloping is one of the critical problems in ScanSAR images. It not only affects image visualization, but also influences the quantitative applications such as surface wind and wave retrievals in the ocean area. The existing method of descalloping needs artificial parameter setting and lacks generality in the image domain. A novel deep neural network based on residual learning for descalloping of ScanSAR images is proposed in this paper. The proposed method can eliminate scalloping patterns and has strong adaptive ability, which can handle inhomogeneous scalloping patterns and different scenarios. Experiments on GF-3 ScanSAR images verify the good performance of this method. The code for our models is available online.
关键词： synthetic aperture radar (SAR),deep neural network,scalloping patterns,ScanSAR,Residual learning
更新于2025-09-23 15:22:29
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Two-dimensional Spectrum for Diving Stage SAR Processing with High-order Equivalent Range Model
摘要： For airborne synthetic aperture radar (SAR) processing in its diving stage, the diving velocity brings additional range variance to the range history in the synthetic aperture time. The traditional hyperbolic range model is not accurate enough to approximate the actual range equation and the precise two-dimensional spectrum cannot be achieved. In order to address this problem, a highly accurate spectrum deduction based on high-order equivalent range model is proposed in this paper. By introducing the high-order terms, more degrees-of-freedom are obtained for the equivalent range model and the actual range history can be accurately fitted. Based on the achieved range model, the two-dimensional spectrum for diving stage SAR can be accessed. Simulation experiments are carried out to validate the effectiveness of proposed spectrum.
关键词： two-dimensional spectrum,diving stage,range model,Synthetic aperture radar (SAR)
更新于2025-09-23 15:22:29
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Effect of Non-Uniform Azimuth Sampling on Sar Image Formation Evaluated at 79Ghz
摘要： Conventional synthetic aperture radar (SAR) image formation requires uniform sampling along the azimuth direction. These image formation relies on frequency domain algorithms including the Range-Doppler Algorithm (RDA), Chirp-Scaling Algorithm (CSA) [1] etc, that make use of azimuth Fast Fourier Transform, hence the requirement of uniform sampling. While uniform sampling in space is not always achievable, the samples can be interpolated onto a uniform grid given the sampling rate is Nyquist. This paper studies the effect of SAR image formation when the azimuth sampling is not uniform, and not Nyquist in some interval. The results showed that even if there is a wide interval in the middle of the synthetic aperture with no samples, an image can still be formed. This result could be useful when the SAR antenna is a phased array, or when the hardware is generating bursts of pulses followed by a quiet window.
关键词： Image focusing,Back-Projection,Azimuth Sampling,Synthetic aperture radar
更新于2025-09-23 15:22:29
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Operational Agricultural Flood Monitoring with Sentinel-1 Synthetic Aperture Radar
摘要： Agricultural flood monitoring is important for food security and economic stability. Synthetic Aperture Radar (SAR) has the advantage over optical data by operating at wavelengths not impeded by cloud cover or a lack of illumination. This characteristic makes SAR a potential alternative to optical sensors for agricultural flood monitoring during disasters. The purpose of this study is to assess the effectiveness of using freely available Copernicus Sentinel-1 SAR data for operational agricultural flood monitoring in the United States (U.S.). The operational detection of flood inundation was tested during Hurricane Harvey in 2017, which resulted in significant flooding over Texas and Louisiana, U.S. This paper presents 1) the agricultural flood monitoring method that utilizes Sentinel-1 SAR, the NASS 2016 Cultivated Layer, and the NASS 2016 and 2017 Cropland Data Layers; 2) flood detection validation results and 3) inundated cropland and pasture acreage estimates. The study shows that Sentinel-1 SAR is an effective and valuable data source for operational disaster assessment of agriculture.
关键词： Hurricane Harvey,Flood Detection,Synthetic Aperture Radar,Agriculture Flood Monitoring,Sentinel-1
更新于2025-09-23 15:22:29
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Optronic High-Resolution SAR Processing with the Capability of Full-Resolution Imaging
摘要： The improvement of synthetic aperture radar (SAR) resolution brings a broader applications but poses a great burden for SAR data processor. Real-time processing becomes a difficulty. Optronic technology has been developed for SAR real-time processing due to its ultrafast processing speed. A novel real-time optronic high-resolution SAR processor is proposed in this paper. It has the capability of full-resolution imaging. Restricted with the data scale of spatial light modulators (SLMs), SAR raw data cannot be all encoded onto the light beams at a time. To solve this, subaperture architecture is introduced in our system scheme. SAR data is optically processed in parallel by multiple optical subaperture processing modules and synthesized into a full-resolution SAR image. The module is implemented by multiple SLMs and lenses, which is innovatively proposed in this paper. The proposed system is applicable to large-scale SAR data processing, and the data scale is easy to extend with implementation of adding identical optical subaperture processing modules. Airborne SAR real data is used in the experiment, and a high-resolution image is also given. The PSLR of the focus results with and without subaperture partition are analyzed, which validate the satisfying image quality of the proposed algorithm.
关键词： high resolution,synthetic aperture radar,spatial light modulator,subaperture,full-resolution imaging,Optronic processing
更新于2025-09-23 15:22:29