To process squinted sliding-spotlight synthetic aperture radar data, the azimuth preprocessing step based on linear range walk correction (LRWC) and derotation operations is implemented to eliminate effect of 2-D spectrum skew spectral aliasing. However, two key issues arise from preprocessing. First, traditional chirp scaling (CS) kernel not suitable for data focusing because property changed significantly; second, spatial variation targets' Doppler rates along direction due LRWC operation...

Notch filter is one of the most popular techniques for Radio Frequency Interference (RFI) suppression in wideband Synthetic Aperture Radar (SAR). In this work, we have `TerraSAR-X' data affected by a near zero RFI (radio frequency interference), modulated with pulse wave, which creates side lobes domain, and difficulty filtering kind RFI. data, notch will eliminate frequency, but create transient response after discontinuity non zeros signal; paper, technique has been used forward backward...

A novel method is proposed for azimuth sidelobes suppression using multi-pass squinted (MPS) synthetic aperture radar (SAR) data. For MPS SAR, the observes scene with different squint angles and heights on each pass. The SAR mode acquisition geometry given first. Then, 2D signals are focused images registered to master image. Based new signal model, elevation processing incoherent addition introduced in detail, which main parts suppression. Moreover, parameter design criteria derived best...

Spaceborne global navigation satellite system reflectometry has been used to retrieve wind speed, but few studies have directly detected tropical cyclones from spaceborne GNSS-R observations. Moreover, it is challenging solve the multivalued dependence of observable on speed unambiguously and accurately in cyclone conditions. This paper presents a single-pass detector coarse estimation approach position using full delay-Doppler map (FDDM). When specular point passes through cyclone, FDDM...

Spaceborne squinted sliding spotlight synthetic aperture radar (SAR) can achieve high-resolution image with well flexibility. However, traditional imaging algorithm cannot focus its data, as the serious coupling between range and azimuth spectral aliasing problem. To process a refined two-step is proposed in this paper. Firstly, linear cell migration correction (LRCMC) De-rotation are adopted to solve Then data focused modified wavenumber domain (WDA). Also, nonlinear chirp scaling (NCS)...

For high resolution spaceborne SAR system, the errors caused by straight trajectory assumption and stop-go approximation cannot be ignored. In this paper, an algorithm is proposed to compensate above errors. First, a novel modified hyperbolic range equation (MHRE) introduced describe satellite's orbit which more precise than traditional (THRE). Then, accurate signal model without deduced based on MHRE. What's more, residual phase in two-dimensional frequency domain two error sources are...

Conventional synthetic aperture radar (SAR) systems cannot achieve both high-resolution and wide-swath imaging simultaneously. This problem can be mitigated by employing multiple-azimuth-phases (MAPs) technology for spaceborne sliding spotlight SAR systems. However, traditional algorithms have met challenges to process the data accurately, due range model error, MAPs reconstruction problem, high-order cross-coupling phase error variation of Doppler parameters along azimuth direction....

ABSTRACT Climate change poses a considerable threat to humanity. This study aims explore the effects of meteorological factors on drinking water quality in urban and rural areas tropics. Drinking was assessed by performing correlation logistic regression analyses South China from 2021 2023. Results showed that fluorine chemical oxygen demand were low north countryside. The total bacterial count (TBC), sulfate, chloride, manganese, dissolved solids, arsenic, ferrum, nitrate, hardness, pH...

Squinted multi-channel SAR is a available mode to achieve the high-resolution and wide-swath, because it more flexible than broadside SAR. However, traditional processing algorithm of not suitable for squinted mode, high squint angle will lead reconstruction fail. In this paper, modified method adapted multichannel signal proposed. The large central Doppler frequency spectrum taking into account, accordingly. Meanwhile, range walk correction performed before remove mismatch between filters...

The multi-azimuth-angle (MAA) UAV SAR is introduced in this paper. Compared with the traditional TomoSAR that rebuilds 3-D scene only from boresight aspect, MAA can rebuild different multi azimuth angles and then provide multiple or even full aspects image by novel formation algorithm presented Firstly, introduced, followed 2-D imaging to focus raw data. Then, a squinted tomography method provided obtain using images same angle. Finally, are geolocated fused construct image. Imaging results...

An improved imaging algorithm is proposed for processing high resolution spaceborne squinted sliding spotlight SAR data in this paper, which includes four steps, namely, azimuth preprocessing, coarse focusing, fine focusing and geometry correction. In the a linear range walk correction (LRWC) filter used to mitigate two-dimensional (2-D) spectral skew, modified subaperture method performed increase size of data, obtain 2-D without aliasing. Then ω-k kernel realize focusing. However,...

Aiming at the problem of SAR image target recognition, A novel network structure combining convolution auto-encoding and convolutional neural is proposed in this paper. First, can denoise then use to recognize image. We draws on idea Googlenet that layer uses a combination multi-size filters learn features different sizes. Our method has achieved satisfactory accuracy by testing MSTAR data set.

Objective: With the increasing attention to health influence by ecology environment and climate changes, it is important explore characters of drinking water quality meteorological factors at tropical areas South China. This study aims municipal source elucidate relationship between changes climatic Haikou. Methods: By analyzing data indexes in past five years from July 2013 April 2017, representative as following were analyzed: Fecal coliforms (FC), ammonia nitrogen (NH4+), Nitrate(NO3-),...

Soil microorganisms are one of the important biological indictors soil quality and can reflct comprehensive ecological environment characteristics soil. The research microbial diversity is key to know functions balance with In this paper, high-throughput sequencing on PCR-amplified 16 S rRNA gene V3-V4 fragments was used determine bacterial in rhizosphere A. macrocephala under treatment BZJN1 or streptoprofen. results showed that there were no significant differences bacteria streptoprofen...

The bistatic synthetic aperture radar (SAR) system, based on an inclined geosynchronous earth orbit (GEO) illuminator and a low-earth-orbit (LEO) receiver, has the advantages of high spatial temporal resolution, higher signal-to-noise ratio (SNR) good concealment. In this paper, new system InSAR with one GEO transmitter two LEO receivers is studied. Firstly, we employ Hill equation to design formation configuration between SAR receiving platforms. vertical baseline can be formed receivers,...