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In view of the limitation of the range factor on analyzing low probability of intercept (LPI) performance of MIMO radar systems, a performance parameter is derived and applied for quantifying the LPI performance of distributed MIMO radar systems. A series of contour charts have been given with different values of geometrical parameter. By plotting and analyzing these charts, the LPI performance can be obtained intuitively. Simulation results show that LPI performance of distributed MIMO radar systems depends on both radar parameter and system geometry. It is shown that the spatial diversity gain plays an important role in designing a distributed MIMO radar system with robust LPI performance. [ABSTRACT FROM AUTHOR]

The bandwidth will get narrow when the size of HF antenna is small. To overcome this problem, a novel miniaturized HF antenna composed of hemispherical wire grids with performance similar to the electric dipole is presented in this paper. The antenna has simple structure and is easy to feed. The largest dimension of this antenna is 3. 6 m, which is 3. 6% of its lowest frequency wavelength, and 36% of its highest frequency wavelength. The antenna is simulated with the help of CST MWS. A 1/5 scale model is manufactured and measured. The results demonstrate that the relative impedance bandwidth is 40% without loading or external matching networks while maintaining acceptable performance. A method of broadening frequency range by loading lumped elements is further discussed, and simulation and test verification have been done. The designed antenna can be widely used in HF communication system, over-the-horizon radar and so on. [ABSTRACT FROM AUTHOR]

In spaceborne SAR (Synthetic Aperture Radar) , the pulse compression of LFM (Linear Frequency Modulated) signal would be affected by the system phase error which changes in the space environment. Therefore a method of in-orbit phase pre-distortion for LFM signal based on polynomial fitting is put forward, in which the system phase error is obtained by in-orbit calibration, the phase compensation parameters are obtained by polynomial fitting on ground, and by uploading phase compensation parameters, LFM signal with compensation phase is generated by in-orbit calculation. The basis of the theory is described, as well as the realizing flow of the method is presented. Also, hardware requirements and advantages of the method are analyzed. The method is compared with other methods, and is verified to be efficient by the simulation and experiments in real system. [ABSTRACT FROM AUTHOR]

For a bistatic HF radar, the bistatic angle, ocean current and physiognomy of receiver location will bring about the Bragg lines' spreading, peak split and peak shift, so that the first order ocean clutter will be detected and tracked as a false target in some cases. To solve this problem, a fast method is proposed to suppress the ocean clutter. Based on some priori knowledge and stationary properties of the ocean surface, the ocean clutter frequency range to be suppressed was obtained on the Range-Doppler(RD) spectra. Then the Clean algorithm was applied to suppress the ocean clutter on the un-beam-formed channel data, after that the digital beam forming was performed and the obtained data were more helpful for target detection. The results show that this method is valid and can be implemented for real-time operation. [ABSTRACT FROM AUTHOR]

A new detection scheme for range-spread broadband radar target using high-resolution range profiles (HRRP) is proposed. The location of the target and the noise power were estimated in a window function, and a fuzzy threshold map was used to refine the target data, then enveloped alignment was carried out through the target moving with a constant velocity. Finally, the detector of fuzzy threshold map dependent generalized likelihood rate test (FTMD-GLRT) was derived based on the estimation of signal steering vector. Remarkably, the detection scheme ensures the constant false alarm rate (CFAR) property with respect to the unknown noise power. Experimental results of the measured data of three kinds of planes show that the proposed scheme achieves a visible performance improvement compared with the scatter density dependent generalized likelihood rate test (SDD-GLRT). [ABSTRACT FROM AUTHOR]

This article briefly analyzes the working process of photovoltaic radar of a certain plane and intraduces the software and hardware design of the equipment for detecting synthetic photovohaic radar parameters based on virtual instrument technology. This thesis emphasizes the common process of testability design and the application in the equipment. The automatic detecting capability of testing and isolating faults in the equipment is obtained due to the application of bulb-in testing (BIT). Thus, the maintainability, usability and reliability of the equipment are effectively improved. [ABSTRACT FROM AUTHOR]

A new approach of automatic classification of the radar emitter signals is presented. This method is based upon the characteristics derived from instantaneous frequencies and contains three sequential steps: firstly, the instantaneous frequencies of radar emitter signals are extracted via the improved instantaneous autocorrelation algorithm; secondly, a two-times-normalizations based feature re-extraction approach is used to obtain the classification characteristic vector; finally, the kernelized fuzzy c-means clustering with validity assessment is carried out to categorize the considered signals automatically. The results of simulation experiments show that, the characteristic vector can reflect the differences of signals with different modulation types and has a good ability to resist noises. The proposed scheme of signals classification can achieve the overall success rate of above 95% , even at the signal to noise ratio of 6dB. [ABSTRACT FROM AUTHOR]

To better apply the ADBF at subarray level to the phased array radar, the two-dimensional ADBF method at subarray level was studied. A signal model of ADBF at subarray level is presented, which is suitable for plane phased array. The normalization method was introduced into the two-dimensional ADBF at subarray level, which normalized the subarray outputs to make the noise power of each subarray be the same, and the desired quiescent pattern was achieved in the absence of jammer, thereby the conversion problem between adaptive and non-adaptive work modes was resolved. The method based on normalization processing can suppress jammer effectively and improve the sidelobe level markedly compared with the conventional method in the presence of jammer. Simulation results indicate the validity of the introduced methods. [ABSTRACT FROM AUTHOR]

In order to provide a good simulation platform to study the passive radar seeker, video signal simulation was adoped to model and simulate the passive radar seeker, and a simulation platform was built up. In the experiments, the simulation results of passive radar seeker in typical war environment were provided, which verifies the correctness of our model and the robustness of our platform. [ABSTRACT FROM AUTHOR]

This paper introduces the theory of short-time FFFT? as well as the wavelet transform, and uses this theory to analyze the monitoring of weak signal of radar in strong-noise background. The corresponding basic-function and discrete algorithm are also given. Finally, the simulation result is provided by computer. [ABSTRACT FROM AUTHOR]