{"title":"Surface Deformation Monitoring Induced by Volcanic Activity of Mount Agung, Indonesia, by PS-InSAR Using Sentinel-1 SAR from 2014-2021","authors":"I. Nyoman Sudi Parwata, T. Osawa","doi":"10.1109/APSAR52370.2021.9688489","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688489","url":null,"abstract":"Mount Agung is an active volcano located in Bali island, Indonesia, which had been dormant since 1963. However, Mount Agung began to show volcanic activity with severe earthquakes in August 2017. The intense seismicity peaked in early October 2017, and the volcano did not erupt until November 21, 2017. However, a violent explosive eruption with rapid lava-spewing occurred, forcing 140,000 people to evacuate between November 25 and 29, 2017. This study aims to monitor surface deformation induced by volcanic activity of Mount Agung by Persistent Interferometric Synthetic Aperture Radar (PS-InSAR) using Sentinel-1 SAR from 2014-2021. This study employed 250 Sentinel-1 SAR satellite images (from October 2014 to April 2021). These results show that displacement increased from May to November 2017 and then decreased for about a year and a half before increasing from May to July 2019. The seismic activity started again on May 28, 2019, and the volcano erupted on June 13, 2019. Before this period, PS-InSAR had detected a small sign of increasing displacements, especially in the northern part of Mount Agung. Furthermore, PS-InSAR provided the surface displacement results from the pre-eruption, co-eruption, and post-eruption periods. These results will be significant for understanding the active cycle of Mount Agung and for predicting future potential crisis periods.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128403566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High-Squint SAR Imaging Technique Based on Multi-Chip DSP","authors":"Lan Dong, Xingwei Meng, Daiyin Zhu","doi":"10.1109/APSAR52370.2021.9688347","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688347","url":null,"abstract":"High-speed digital signal processor (DSP) can solve the time-consuming issue of synthetic aperture radar (SAR) imaging for promoting its application in both military and civilian communities. In this paper, an entire processing chain using two multi-core DSPs for high-squint SAR data imaging, including azimuth filtering and decimation, improved polar format algorithm (PFA), phase gradient autofocus (PGA), image quantization, and return for display, is proposed. The multi-chip DSP architecture can improve the computational efficiency of high-squint and high-resolution SAR imagery generation. Finally, measured SAR imaging results demonstrate the algorithm chain and its parallel architecture that each multicore DSP TMS320C6678 can process the image of 4096*2048 pixels within 1.25 seconds. Moreover, while two chips cooperate in a ping-pong manner, two frames will be obtained after 1.53 seconds, enhancing the processing efficiency by 61 % approximately.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121946610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ka-Band Drone SAR Flying without GPS","authors":"Weixian Liu, H. Feng, Yilong Lu","doi":"10.1109/APSAR52370.2021.9688524","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688524","url":null,"abstract":"This paper presents a low-cost Ka-band drone-borne Synthetic Aperture Radar (SAR) imaging system flying without motion sensor. This study is motivated by the demands from industry for a smaller, lighter and low-cost microwave camera after our successful development of a Ku-band drone-borne SAR systems a few years ago. The main contribution of this paper is on a robust autofocus algorithm for compensating for the platform motion errors due to platform engine vibration and air turbulence without GPS.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122672467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sangho An, Duk‐jin Kim, Ji-hwan Hwang, Juyoung Song
{"title":"Implementation of ATI-GMTI process on Airborne and Automobile SAR data","authors":"Sangho An, Duk‐jin Kim, Ji-hwan Hwang, Juyoung Song","doi":"10.1109/APSAR52370.2021.9688393","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688393","url":null,"abstract":"This paper presents the methodology to implement Ground Moving Target Indication (GMTI) with Along Track Interferometry (ATI) process on two kinds of data achieved from different platforms, i.e., airborne and automobile. Raw data were acquired by direct experiment on the bistatic Frequency Modulation Continuous Wave-Synthetic Aperture Radar (FMCW-SAR) system, which is useful for constructing small-sized SAR systems. The acquired raw data were processed by Range Doppler Algorithm (RDA) to form Single Look Complex (SLC) images. Following that, SAR images from two channels were precisely co-registered to generate interferogram that includes the target velocity information. Furthermore, residual phase component, flat-earth phase, was removed from the interferogram by executing platform motion compensation. Distinguishing geometrical structure of airborne system and automobile system impact on extracting target velocity are being studied through a series of GMTI experiments and subsequent analysis.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122807587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-Scale Capsule Network with Coordinate Attention for SAR Automatic Target Recognition","authors":"Hui Xu, F. Xu","doi":"10.1109/APSAR52370.2021.9688428","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688428","url":null,"abstract":"Deep learning-based approaches have made impressive achievement in synthetic aperture radar automatic target recognition (SAR-ATR), due to its powerful ability to extract hierarchical features. However, data-driven neural network requires a large amount of labeled data, which is hardly obtained especially in SAR target recognition. Recently capsule network shows its potential to perform well with few training samples. Thus, this paper proposals a novel neural network based capsule network to achieve comparable performance with limited data. It is composed of an encode network and a decode network. we deploy multi-scale feature extractor and coordinate attention to extract robust features by multiple dilated convolution layers. Then we adopt capsule module to encode and preserve spatial information. The decoder network consisting of three fully connected layers is used to reconstruct input images and encourage capsules to learn discriminative features. The MSTAR 10-class dataset is used to evaluate and demonstrating the effectiveness of the proposed framework. Our experimental result shows that it can achieve high overall accuracy up to 99.59% using all training samples and 89.92% even if only 20% training samples are applied without data augmentation.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122387315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiangfeng Zeng, Shunjun Wei, Jun Shi, Xiaoling Zhang
{"title":"Efficient Instance Segmentation Method For High-Resolution SAR Imagery","authors":"Xiangfeng Zeng, Shunjun Wei, Jun Shi, Xiaoling Zhang","doi":"10.1109/APSAR52370.2021.9688454","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688454","url":null,"abstract":"Benefiting from the characteristic of synthetic aperture radar (SAR), ship detection plays a crucial role in military purposes recently. Meanwhile, the methods developed by convolutional neural networks are superior in precision, detection speed, and migration ability to traditional methods. However, bounding boxes used in ship detection merely perform instance-level detection which comprises ship and background in the detected result. In terms of this defect, we introduce instance segmentation in SAR imagery for extracting the contour of the ships. Compared to ship detection with bounding boxes, instance segmentation implements pixel-level prediction for the ships, and the predicted mask eliminates background information, which provides the contour and azimuth of the ships. Furthermore, we proposed DB loss and high-resolution representations for instance segmentation. Quantitative and visualized results demonstrate proposed method improves average precision (AP) and reduces the model size compared to Mask R-CNN. Besides, it can accurately segment the hard samples, e.g., offshore ships, small ships, and ships in the port, which has a broad application vision in interpreting SAR images.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126533718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-Sensor Satellite-Imaging Data Fusion for Earthquake Damage Assessment and the Significant Features","authors":"Gunjan Joshi, R. Natsuaki, Akira Hirose","doi":"10.1109/APSAR52370.2021.9688438","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688438","url":null,"abstract":"With the recent developments in remote sensing technologies, the resolution and detection capabilities of both synthetic aperture radars (SAR) and optical sensors have increased significantly enough to detect damages of earthquakes. However, extensive human labor and domain expertise is required for processing and analyzing large areas affected by disasters. We propose a multi-sensor data fusion-based neural network, which combines the datasets from a SAR and an optical sensor for the damage detection of the 2018 Sulawesi earthquake in Indonesia. We also try to understand which input features are the significant contributors for which classification outputs.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"17 81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124810079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chaerin Chung, Sumin Kim, Jeongbae Kim, Uimin Lee, Byungdoo Lee, M. Ka
{"title":"Analysis on the Impact of Constellation Configuration over Multistatic SAR Images","authors":"Chaerin Chung, Sumin Kim, Jeongbae Kim, Uimin Lee, Byungdoo Lee, M. Ka","doi":"10.1109/APSAR52370.2021.9688406","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688406","url":null,"abstract":"Multistatic synthetic aperture radar (SAR) is a SAR system consisted of multiple transmitters and receivers. A multistatic SAR system is highly flexible in the selection of radar parameters compared to a monostatic SAR system. The image quality can be adjusted by controlling the parameters of a multistatic SAR system. In this paper, a multistatic SAR system is simulated where the distance between the satellites is varied. The numerical simulation assumed three satellites traveling in the along track configuration. One of the satellites was used as transmitter and receiver, and the others were used as receivers. The back-projection algorithm was modified to synthesize a radar image using multistatic SAR data. Multiple multistatic SAR with different distance between the satellites were simulated. The resolution and peak sidelobe ratio (PSLR) of multistatic SAR image were analyzed.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134312640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nan Gan, Qilei Zhang, Yongsheng Zhang, Yifei Ji, Z. Dong, Lei Yu
{"title":"Analysis of the Spatial-variation Features of Scintillation Phase Error in Spaceborne Synthetic Aperture Radar Images","authors":"Nan Gan, Qilei Zhang, Yongsheng Zhang, Yifei Ji, Z. Dong, Lei Yu","doi":"10.1109/APSAR52370.2021.9688351","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688351","url":null,"abstract":"The amplitude and phase scintillation effect imposed by ionospheric irregularities result in low frequency spaceborne synthetic aperture radar (SAR) azimuth-imaging defocus. Different from the motion phase error and tropospheric phase error, the scintillation phase error (SPE) shows spatial-variation features for distinct targets in scene. This paper constructs the ionospheric propagation geometry of spaceborne SAR for spatial distinct targets, and analyzes the spatial variation features of SPE along azimuth, range and anisotropic extending projection direction. The simulation results demonstrate that the SPE is overlapped along the azimuth direction and has similar characteristics along the anisotropic extending projection direction. Besides, the SPE changes slowly along the distance direction under isotropy, but has the characteristics of staggering under anisotropy. These features will be further applied in estimating and compensating SPE.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126430898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An Improved Signal Processing Algorithm Based on Doppler Shifting Technique for Video-SAR","authors":"C. Kim, S. Park","doi":"10.1109/APSAR52370.2021.9688536","DOIUrl":"https://doi.org/10.1109/APSAR52370.2021.9688536","url":null,"abstract":"One of the technologies in synthetic aperture radar (SAR) is Video-SAR (ViSAR). Previously, we proposed a new signal processing method to generate the multi-frames of ViSAR using Doppler shifting technique via sub-aperture. In this conference, we announce an improved Doppler shifting technique using Fractional Fourier Transform (FrFT). FrFT is one of the Signal Transform methods, which is to classify each signal from the overlapped frequency band. The previous technique only uses the matched filter in the slow-time plane to compress the interested signal. However, it cannot sufficiently guarantee the interested signal in a strong interfering environment. Therefore, to increase the quality of the signals for ViSAR frames, we apply FrFT into the Doppler shifting technique. By using FrFT technique, not only the quality of the interested signal has improved, but also a function to distinguish moving targets has been added. As a result, this proposed method is more efficient than the previous one, and at the same time, it also proposes a ViSAR algorithm with high performance by adding GMTI functions. We have performed the practical experiments using X-band chirp pulse SAR system mounted on an airplane to verify the proposed method.","PeriodicalId":104561,"journal":{"name":"2021 7th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR)","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114987192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}