The traditional methods of jamming against synthetic aperture radar (SAR), which are implemented based on linear frequency-modulated (LFM) signals, currently unable to meet the needs electronic countermeasures. Compared with LFM signal, frequency nonlinear (NLFM) signal varies nonlinearly time. Because this time-frequency structure, NLFM is naturally mismatched matched filter SAR; thus, a stronger and more flexible effect produced. In article, used in SAR field for first time, smart method...

Synthetic aperture radar (SAR), as a wideband system, is easily contaminated by radio frequency interference (RFI), which affects the imaging quality of SAR. The subband spectral cancellation (SSC) method and its modifications utilize SAR single-look complex (SLC) image to realize RFI extraction mitigation subtracting between sub-images, are robust efficient for engineering applications. In past, traditional SSC was often applied narrowband (NBI) mitigation. However, when it used (WBI)...

Although the multiple-phase-sectionalized-modulation (MPSM) jamming can produce barrage effects in a local range, range of can't be controlled. Against this disadvantage, an improved MPSM method based on non-linear frequency-modulate (NLFM) signal, i.e., MBN, is proposed paper. The MBN realizes control fast time domain controllable time-frequency structure NLFM signal. To generate desired shaping factor defined. Subsequently, feasibility and effectiveness are confirmed by simulation experiments.

Synthetic aperture radar (SAR) is an advanced ground-observing remote sensing technology, and high-resolution wide-swath (HRWS) imaging has always been the goal of SAR. In general, improved azimuth resolution requires a large pulse repetition frequency (PRF), resulting in high system requirements. To overcome this difficulty, multichannel technology gradually developed, achieving HRWS decreasing PRF by increasing spatial sampling, i.e., number antenna subapertures azimuth. This article...

Vortex electromagnetic waves, which carry the orbital angular momentum (OAM), can increase channel capacity by utilizing OAM multiplexing technology in optical field. In order to fully exploit mode-division radio domain, a crosstalk matrix of communication between multi-OAM-mode transmission and reception is deduced theoretically this letter. The shows that it achievable communicate same modes but not possible different modes. To confirm statement, near-field proof-of-concept experiment,...

Due to advantages such as low power consumption and high concealment, deceptive jamming against synthetic aperture radar (SAR) has received extensive attention in electronic countermeasures. However, the false targets generated by most of methods still have limitations, poor controllability strong regularity. Inspired idea waveform coding, this paper proposed a repeater-type SAR method through joint encoding amplitude phase intra-pulse inter-pulse, which can generate two-dimensional...

Synthetic Aperture Radar (SAR) is a high-resolution radar that operates all day and in weather conditions, so it has been widely used various fields of science technology. Ship detection using SAR images become important research marine applications. However, complex scenes, ships are easily submerged sea clutter, which cause missed detection. Due to this, strong sidelobes generate false targets reduce the accuracy. To solve these problems, ship method based on eigensubspace projection...

The azimuth multi-channel synthetic aperture radar (MC-SAR) systems can simultaneously realize high-resolution and wide-swath (HRWS) earth observations. However, channel phase bias inevitably exists in the practical work of MC-SAR system, which is main factor for “virtual target” SAR images. To accurately estimate bias, a estimation approach based on modified kurtosis maximization (MMK) proposed this paper. By analyzing echo characteristics SAR, constructs objective optimization function MMK...

Lunar crater ejecta can provide important information regarding the impact cratering process and properties of subsurface materials. However, mapping range has been hampered by degradation lunar surface’s morphological features. Polarimetric synthetic aperture radar (SAR) is an effective technique to determine scattering characteristics surface subsurface, for distinguishing fresh from surrounding regions. This letter uses a three-component compact decomposition Mini-RF data identify floor,...

The empirical mode decomposition (EMD) based method for mitigating radio frequency interference (RFI) has the capability of removing narrow-band RFI and advantage easy-to-implement. signals are decomposed by EMD into a finite number intrinsic functions (IMFs) in pulse-by-pulse manner, then IMFs corresponding to subtracted achieve mitigation. However, useful will be lost using this method, which reduces synthetic aperture radar (SAR) imaging quality. In letter, modified is proposed tackle...

The concept of spaceborne interrupted frequency-modulated continuous-wave (IFMCW) synthetic aperture radar (SAR) subverts the design principles traditional (FMCW) SAR system, which uses a single physical antenna to transmit signal and receive echo alternatively. Due demand turning off receiver in process transmitting signal, periodical data-missing phenomena will be aroused data, missing ratio is close 50%. When imaging algorithms were used artifacts, appearing as periodically...

Orbital angular momentum (OAM) beam is very difficult to receive due the divergence of beam. The position axis must be known by existing receiving methods, including single point method and phase gradient method. This article proposes an OAM mode estimation with unknown axis. first estimates according characteristics then uses estimate mode. simulation results verify effectiveness

Synthetic Aperture Radar (SAR) images of Sentinel-1 (S-1) in Interferometric Wide (IW) swath mode, which are widely used for land and ocean services, but affected by severe radio frequency interference (RFI). Single Look Complex (SLC) data containing phase amplitude information is the most popular product type SAR applications. The sub-band spectral cancellation (SSC) method extracts suppresses RFI SLC through making a subtraction among different sub-images, efficient strong enough to be...

Synthetic aperture radar (SAR), as an active microwave remote sensor with high-resolution earth observation, is easily affected by radio frequency interference (RFI). Pulse (PRFI), a typical form of RFI, pollutes SAR raw data bright stripes, which increases the difficulty image interpretation. However, conventional eigen subspace projection (ESP) method decomposes whole pulse into interferences and useful signals, resulting in loss signals non-interference positions pulse. To solve this...