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The space-based passive radar provides a greatly improved capability for worldwide surveillance and anti-radiation missiles, compared with terrestrial and airborne based system. It is the purpose of this paper to discuss the system performance, technology characteristics of passive bistatic radar based on space-based illuminators. A preliminary guidance performance evaluation of this type of radar...
Interrupted-sampling and direct transmitting scatter-wave jamming(SWJ) can form multiple false targets to Inverse Synthetic Aperture Radar(ISAR), while pseudo-random sequence phase-modulation spreads the spectrum of modulated signal. In this paper we propose an active quasi-coherent depress jamming signal by combination of the two methods. The jammer firstly intercepts the radar signal by interrupted-sampling...
It is found that super-resolution algorithm is influenced seriously by landform in the course of usage. The reason is that the reflection echo model is not matched to the true signal radiate path. The raytracing method is adopted to make the model more close to the true signal radiate path, and the landform adaptability of super-resolution algorithm is improved. Results of emulation and experiment...
A new design method of FFT processor is proposed based on conflict-free memory access to satisfy the requirements for both high data throughout rate and low logic resource utilization. Aiming to realize a 1024/256 point compatible FFT processor with radix-4, decimation in time algorithm and block floating point arithmetic, four separate memory blocks are used to achieve conflict-free parallel data...
This paper present a design for X/Ku dual-band reflectarray antennas with single layer which has two independent radiation patterns for X and Ku bands. In the design, a novel dual resonance structure has been used as the unit cell for both X and Ku band to achieve dual-band performance with a new approach. A 10×10 center-fed reflectarray operating at 9 GHz and 13.5 GHz with scattering angles of 12°...
In this paper, we propose an improved InSAR phase filter in frequency domain based on the Goldstein filter. Firstly, we use different window size determined by the coherence to suppress phase noise. Secondly, we use fringe frequencies compensation to eliminate the effect of the terrain topography. Thirdly, we excute the phase filtering procedure pixel by pixel with a new filtering parameter. Another...
As the effective means for achieving sparse microwave imaging, sparse reconstruction algorithms (SRAs) can be generally classified into four main categories: greedy pursuits, ℓ1-norm minimization, nonconvex optimization and Bayesian framework. In this paper, we compare the performance of the typical SRAs in synthetic aperture radar (SAR) imaging. We consider four algorithms including the orthogonal...
Conformal arrays are widely used in advanced aircrafts because of their aerodynamic performance. However, the conformal arrays involve lots of array elements, moreover, their peak sidelobe levels of radiation pattern are relatively high, which is adverse to the engineering application. Focusing on the above problems, this paper applies the genetic algorithm to thin the array elements of the typical...
This paper proposes a new approach for the detection and location of multiple ground moving targets in the synthetic aperture radar (SAR) system. For multiple targets with various parameters in the scene with weak static clutter, it is difficult to process all the targets simultaneously, such as the estimation and compensation of Doppler frequency centroid, the estimation of Doppler chirp rate and...
As the existent filters haven't good effect in denoising and preserving edge for intensity image, a wavelet threshold denoising algorithm based on homomorphic transform has been put forward. The wavelet threshold and the selection of threshold function are focused on, then the former is determined through the use of particle swarm optimization algorithm and the latter is obtained by the creation of...
There has been an increasing interest in the use of spaceborne SAR for measuring forest biomass which requires the use of longer wavelengths for enhanced foliage penetration. However, the propagation characteristics of the wave will be seriously affected by the ionosphere, especially below P-band (500 MHz). In this paper, the ionospheric effects of the spaceborne SAR in range direction are theoretically...
In allusion to the problem of the base-line selecting of distributed aperture coherence-synthetic radar, two types of criterions that the echo-correlated and the echo-coherent are proposed with the mathematic description, and the base-line is computed under typical scene with its application mode, which builds the base for the research and application of this system of radar.
P-band space-based bistatic radar can globally detect and track moving targets with very strong penetration ability and has become an important research field in the radar community recently. This paper discusses the problems of the designing the P-band bistatic space-based radar such as the characteristics analysis of the target RCS, the antenna size analysis, the effect of ionosphere and the influence...
The moving target in low frequency SAR is usually flooded in the clutter spectrum and has low SCR (signal to clutter ratio). Furthermore locating moving target in the single-channel low frequency SAR (Synthetic Aperture Radar) will meet the problem of "azimuth position uncertainty". This paper solved this problem by the azimuth antenna pattern. It deduces the relationship between the 2-dimensional...
An active frequency selective surface (FSS) is designed, and is combined with Radar Absorbing Materials to form a composite absorbing structure. Based on the equivalent theory that the PIN diode can be regarded as resistance, the voltage-loading resistance of active FSS element is researched for RAM containing FSS, and the electromagnetic wave reflectivity performance is analyzed. The influence of...
Clutter suppression is a key problem for multi-channel SAR ground moving target indication (GMTI), which is sensitive to the correlation among channels. For real multichannel SAR-GMTI system, there are inevitably slight differences in the frequency response and antenna patterns among channels. Therefore, the correlation of channels will be worsen and channel balancing is a crucial step to obtain a...
In sensor networks, resource management is very important for both improving the performance of the system and decreasing the expenses to accomplish the tasks of the networks. Efficient resource management can help us to control the networks appropriately and quickly. In this paper, we consider the problem of adaptive resource management based on target priority in the radar networks. We first propose...
Because of working in L band, geosynchronous synthetic aperture radar interferometry (GEO InSAR) and differential interferometry (GEO D-InSAR) system is sensitive to the interferometric phase screen errors introduced by ionosphere. However, conventional ionosphere time-spatial freezing model used in Low Earth Orbit (LEO) SAR is no longer valid due to the long integration time and large imaging width...
Phase noise is one of the major problems for the radar systems, which implements coherent processing before detection. Coherency disturbance causes loss in SNR and difficulties in multi target detection. Due to the nonlinear correlation characteristics of phase noise, homodyne receivers are more sensitive to coherency problems. Although the main source of phase noise is transmitter phase noise caused...
With the rapid development of satellite-based signal processing technologies comes the widespread deployment of SAR image processing systems in spaceborne applications, many of which are implemented as FPGA-based systems thanks to the introduction of modern programmable devices with high capacity and complexity. However, as raw data of SAR satellites grow in size and bandwidth the effective implementation...
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