Optical image sequences of spacecraft acquired by space-based monocular cameras are typically imaged through exposure bracketing. The feature deformable alignment network for multi-exposure fusion (SFDA-MEF) aims to synthesize a High Dynamic Range (HDR) from set Low (LDR) images with varying exposures. HDR contains details the observed target in LDR captured within specific luminance range. relative attitude camera coordinate system undergoes continuous changes during orbital rendezvous,...

Feature point detection in inverse synthetic aperture radar (ISAR) images of space targets is the foundation for tasks such as analyzing target motion intent and predicting on-orbit status. Traditional feature methods perform poorly when confronted with low texture uneven brightness characteristics ISAR images. Due to nonlinear mapping capabilities, neural networks can effectively learn features from targets, providing new ideas detection. However, scarcity labeled image data presents a...

The 2-D inverse synthetic aperture radar (ISAR) images of space targets vary with the viewing angles and are not suitable for automatic target recognition (ATR), thus requiring 3-D reconstruction techniques. Conventional techniques either use monostatic incoherent processing retrieval or exploit multistatic but coherent reconstruction. In this article, we combined aspects to investigate reflectivity radar. Space objects periodically revisit same ground area. Multipass interferometric...

Attitude estimation for space targets based on inverse synthetic aperture radar (ISAR) is essential various on-orbit operations, including spacecraft status analysis and fall forecast. However, traditional attitude methods ISAR images suffer from poor feature extraction performance. Furthermore, the present can only deal with stabilized spacecraft. In situations where a noncooperative in slow-spinning state, cross-range scaling inaccurate, resulting incorrect estimation. this study, we...

Height extraction by radar remote sensing is an attractive issue for the building detection and recognition. According to analysis on geometrical properties in SAR imagery, a novel height estimation algorithm proposed following model-based structure prediction matching strategy. The range Doppler equation introduced simplified 2D slant image plane. An evaluation function implementing ratio of exponentially weighted averages (ROEWA) also established between predicted observed image. By...

The beyond‐line‐of‐sight (BLOS) ranging of radiation sources can be realised through the troposcatter propagation electromagnetic signals. Present systems are based on multi‐station cross localisation theory wherein synchronisation and data fusion all stations not tractable. signal group delay properties provide a new mechanism that single station conveniently inexpensively. However, for with multibeams, e.g. frequency‐scanned radar, which forms several sub‐beams different elevation angles...

Abstract: Interrupted-sampling repeater jamming (ISRJ) is a kind of intra-pulse coherent decep-tion that can generate false target peaks in the range profile and interfere with de-tection tracking real targets. In this paper, an anti-ISRJ method based on orthogonal waveform proposed, which recognize common interference signals by com-paring sub-signal matched filtering results. For some special scenes where targets cannot be directly differentiated from targets, new recognition energy...

Instantaneous attitude estimation for spacecraft through optical/ISAR fusion observation is a hot topic in space situational awareness. However, due to the imaging characteristics and domain gap between two data types, it difficult autonomously estimate instantaneous based on fusion. In this paper, an automatic multi-feature framework proposed. We deploy semantic feature extraction networks extract associate kinds of robust features optical ISAR images, algorithm considering cross-range...

Microwave over-the-horizon (OTH) propagation through troposcatter is a valuable candidate for remote targets detection. Array antenna promising to handle the contradiction between real-time wide spatial coverage requirement and high gain capture weak scattering signal. The detection tactics performance of array receiving systems are significantly affected by fading correlation antennas, but there no analytical study which considers in passive sensing environments uncooperative targets. In...

A method of extracting the precession period ballistic missiles (BM) in midcourse phase their trajectories with radar cross section (RCS) sequence was presented. The motion analyzed and modeled. Then relationship between missile warhead its RCS discussed. Based on variation characteristics flying sequence, a proposed. Simulation results demonstrated efficiency

Cross-range scaling of sequential inverse synthetic aperture radar (ISAR) images is a vital problem for the three-dimensional (3D) reconstruction spatial targets. Specifically, since angular velocity targets cannot be accurately estimated due to their non-cooperative nature, obtained cross-range coordinates scattering points often have non-negligible errors. The errors may result in serious distortion reconstructed geometry targets, which makes consequent target recognition and...

Troposcatter array signal model and processing algorithm are of great importance when over-the-horizon passive reconnaissance is carried out with troposcatter. This paper studies on troposcatter model, the diffusion phase between different elements found after analyzing inter-relationship element transfer functions,. Moreover, change targets, it known that bigger target azimuth angle is, further distance transmitting receiving antenna wider beam width number then more obvious is. Finally,...

With the advantages of small size and low cost RSSI-based ranging positioning technology is suitable for large-scale applications or indoor environments. Whereas multipath structure radio channel caused by complex environment, as well far field conditions antennas are not feasible due to short propagation distance, have a strong impact on accuracy. The reflection wall inevitable in environment. Two-ray tracing model proposed analyze effect channel. It indicates that closer from wall, greater...

The conventional two dimensional (2D) inverse synthetic aperture radar (ISAR) imaging fails to provide the targets' three (3D) information. In this paper, a 3D ISAR method for space target is proposed based on mutli-orbit observation data and an improved orthogonal matching pursuit (OMP) algorithm. Firstly, scattered field converted into set of 2D matrix by stacking slices along elevation direction dimension. Then, OMP algorithm applied recover target's amplitude information via data....

Single-frame infrared small target detection is a challenging task due to the noise and clutter interference. Recent emerging deep learning methods achieve superior performance compared traditional model-driven methods. However, these data-driven do not possess explicit gradient encoding capability of local contrast To overcome restriction, we propose holistic network (HoLoCoNet) in this letter gradually couple into end-to-end network, which consists multi-scaled multi-directional attention...

In order to obtain better inverse synthetic aperture radar (ISAR) image, a novel structure-enhanced spatial spectrum is proposed for estimating the incoherence parameters and fusing multiband. The method takes full advantage of original electromagnetic scattering data its conjugated form by combining them with covariance matrices. To analyse superiority modified algorithm, mathematical expression equivalent signal noise ratio (SNR) derived, which can validate our algorithm theoretically....

Space target ISAR image components segmentation is an important foundation of space recognition based on image. Considering the difference between and optical main body has diverse distribution pixels from subcomponent in image, this paper proposes a idea that segments after CLEAN: firstly, we develop adaptive region growing method to segment emphatically analyses solves setting problem threshold method; then, order divide residual subcomponent, exploit proximity propose iterative...

The troposcatter over‐the‐horizon (OTH) passive radar plays an important role in the beyond‐line‐of‐sight surveillance, for its high propagation reliability and low probability of interception. However, it has two major limitations, namely, large losses multipath scattering fading. Since captured signals are non‐stationary with signal‐to‐noise ratio, antenna gain is indispensable, which results narrow beamwidth. To deal contradiction between beamwidth real‐time wide spatial coverage, array...

With the improvements of spaceborne and airborne SAR system resolution, applications radar remote sensing has been extended to building 3D geometric information retrieval reconstruction from urban images, which is foundation build-up areas analysis. This paper mainly focuses on problem height estimation a single high resolution (HR) image scenes. A model based method combined with segmentation framework proposed. optimizes new likelihood measure between projection buildings observed over...

Abstract Traditionally, radar‐based localisation systems are designed to deal with targets in line‐of‐sight (LOS) scenarios. However, the performance of those radar is limited by multipath echoes reflected from non‐line‐of‐sight (NLOS) and walls urban areas. In recent years, there has been an increasing interest exploitation methods aided environmental knowledge. Based on space diversity provided effect, this article proposes a novel two‐stage method using single monostatic via association...

The algorithm proposed in this paper aims at solving the problem of star map matching high-limiting-magnitude astronomical images, which is inspired by geometric voting identification techniques. It a two-step relying only on angular features, and adopts reasonable strategy to overcome poor real-time performance when number stars large. focuses application scenarios where there are large dense (limiting magnitude greater than 13, average per square degree 185) image, different from sparse...