In this paper, we investigate the detection of masked weak moving targets in the adjacent fast strong target by using FAPC algorithm. The matched Filter of conventional Pulse Compression radars induces range sidelobes in surrounding a target with high SNR that could mask the smaller targets. The mismatch created in received signal by Doppler phase shift, degrades APC Filter performance in side lobe suppression. In this paper, the FFL-FAPC algorithm is proposed to reduce the range side lobes using the RMMSE estimator in its post-processing method. In various scenarios, we will investigate the detection of masked targets in comparsion with previous methods. Simulation results show that the FFL-FAPC algorithm reduce significantly of computational cost, in addition to provides improved Doppler robustness.

In this paper, exploitation of parallel matched Filters bank based on binary phase code is proposed, to overcome shift Doppler in ground based radars which use Pulse Compression technique. The mismatch loss due to target Doppler shift in radar receiver reduced by odd or even number of these parallel Filters. By increasing the number of Filters over target velocity axis the central Doppler frequencies of the neighbor Filters approach together and consequently the overlap increases and results in the straddling loss decrease in output. Using MATLAB software, the attenuation in the output of the receiver matched Filter due to airborne target velocity was analyzed and a solution to calculate minimum number of Filters is proposed for minimum loss of SNR. Finally, two methods for implementation of parallel matched Filters on FPGA in the airborne targets radar receiver are presented and compared.

The matched Filter in the radar receiver is only adapted to the transmitted signal version and its output will be wasted due to non-matching with the received signal from the environment. The sidelobes amplitude of the matched Filter output in Pulse Compression radars are depended on the transmitted coded waveforms that extended as much as the length of the code on both sides of the target location. In order to detect a weak target in vicinity of strong target, the sidelobes of the matched Filter output resulting from the strong target masked the weak target and didn’ t detect its. Generally, the radar dynamic range is defined by the maximum power ratio to the minimum detectable power that is depended on the level of the threshold and the sidelobe levels. Adaptive algorithms suppress the sidelobe levels to noise level with condition of maintain the range resolution and therefore increase the dynamic range. In this paper, an improved algorithm (in terms of computational cost and Doppler robustness) is proposed based on the minimum mean square error (MMSE) estimator denoted as Flexible Filter Length-Adaptive Pulse Compression Repair ((FFL-APCR)), which Filter length depends on the length of transmitted code. It is also shown that the length of the code is influenced by determining the asymptotic peak sidelobe level and the dynamics range. In addition, the influence of the high-speed target on main lobe broadening and the performance degradation of adaptive Filters is investigated. Finally, extending of radar dynamic range with the proposed (FFL-APCR) algorithm is shown in various conditions and its performance evaluated by mean square error criteria. Where return signals coincide with the transmission of a Pulse, Pulse eclipsing can occur which results in detection performance loss. The mismatches (Doppler phase shift and Pulse eclipsing) degrades performance of sidelobes suppression algorithms. The (FFL-APCR) algorithm suppresses range sidelobes by using a smaller Filter length and reduces the computational cost. Consequently, this algorithm should be computationally efficient (real-time) to enable the practical application of RMMSE.

This article investigates the problem of simultaneous attitude and vibration control of a Flexible spacecraft to perform high precision attitude maneuvers and reduce vibrations caused by the Flexible panel excitations in the presence of external disturbances, system uncertainties, and actuator faults. Adaptive integral sliding mode control is used in conjunction with an attitude actuator fault iterative learning observer (based on sliding mode) to develop an active fault tolerant algorithm considering rigid-Flexible body dynamic interactions. The discontinuous structure of fault-tolerant control led to discontinuous commands in the control signal, resulting in chattering. This issue was resolved by introducing an adaptive rule for the sliding surface. Furthermore, the utilization of the sign function in the iterative learning observer for estimating actuator faults has not only enhanced its robustness to external disturbances through a straightforward design, but has also led to a decrease in computing workload. The strain rate feedback control algorithm has been employed with the use of piezoelectric sensor/actuator patches to minimize residual vibrations caused by rigid-Flexible body dynamic interactions and the effect of attitude actuator faults. Lyapunov's law ensures finite-time overall system stability even with fully coupled rigid-Flexible nonlinear dynamics. Numerical simulations demonstrate the performance and advantages of the proposed system compared to other conventional approaches.

The sensitivity of the radar system and the ability to separate targets, which are defined as two important criteria for any radar system, can be achieved by using the Pulse Compression method, but this is only if there is no clutter in the radar observation range. The presence of various types of clutter in the radar observation range, as a disturbance, disrupts the radar's performance and leads to wrong detection of the target and, as a result, false alarms. Adaptive signal level and detection threshold level compensation, as a solution, can improve radar performance in these environments. Accordingly, in this research, by applying compensation on the level of the transmitted signal and the level of the detection threshold in an adaptive manner, an attempt is made to prevent the misdiagnosis of the target and the occurrence of false alarms in the clutter environment. Several scenarios have been investigated using Barker 13 and 22 codes, and during the simulations, target dimensions, target distance from the radar, and rain rate have been changed. Based on the ROC curve, it has been proven that the proposed method for designing the detection threshold level has a higher detection rate than the OFDM and CFAR methods. It should be noted that all the simulations were done in the MATLAB software environment.

High power Pulses with low widths have many applications in radiation generator devices as flash radiography and high power microwave generators. One of the Compression methods of high power Pulses is magnetic Pulse Compression. In this paper a Tesla generator with saturated core which produces a 200k V voltage Pulse has been designed and then the effect of saturation of the core in the Compression of the output Pulse using Proteus and CST EM Studio codes was studied. Our studies showed that with saturation of the transformer’s core, the magnetic permeability and hence the inductance of the transformer’s coils will decrease and consequently the frequency of current oscillations in the transformer will momentarily increase where it will result in the decrease of the output Pulse width.

Hyperspectral images due to simultaneous acquisition of data in more than hundreds narrow and close spectral bands, have a very high correlation bandwidth. Hence, in order to store in less storage space, higher transmission speed and less bandwidth, they need Compression. Various lossless and lossy methods for Compression are exist, that can be in the spatial domain or in the spectrum domain. But, regard to the importance of spectral information of hyperspectral images in remote sensing, this Compression should be done by this condition that the spectral information of this kind of images is well preserved. Compression methods can be based on either the predictive function or using of a codebook, to compress information. Data Compression can also be done based on transformation coding, which these transformations can be cosine functions (DCTs), wavelet functions (DWTs), or principal component analysis (PCAs). Of course, PCA-based Compression is one of the most effective ways to eliminate image correlations and reduce their volume. Another extension is the method of using curve fitting, which is applied exclusively to compress hyperspectral images due to its effect on the image spectrum. This method uses the spectral signature of the each pixel of image to reduce the feature by finding the closest approximation function to express the curve and storing its coefficients as a new feature for reconstruction compressed data. By replacing these coefficients in the equation of approximation, spectrum reflection curve for each pixel can be reconstructed. This method has very good results in comparison with previous methods such as PCA, but in Compression using this method, the SRC curve has been approximated in some points with distortion. In this paper, we tried to eliminate these distortions, by finding points which have distortion and Breakdown the SCR. On the other hand, by using the Savitsky-Golay smoothing Filter we can also reduce distortion and increase the PSNR. Another way to eliminate or reduce this distortion described in this article is as follow: At the first the spectral signature of each pixel of the intended data is smoothed by a Savitsky-Golay smoothing Filter and then by using a particular method is divided into adjoining adjacent spaces and then a curve is plotted for each slice of data. By choosing the best degree and window length for smoothing and selecting the best degree of numerator and denominator of function, the coefficients of the selected rational function are considered as new features of the image. By using the proposed method, in addition to eliminating the distortion, the PSNR level is became much higher and the reconstructed image quality is very close to the original image.

Considering the devastating effects of near-fault earthquakes, seismologists and engineers have, qualitatively and quantitatively, represented the strong velocity Pulse of near-fault ground motions using models including physical parameters associated with the wave propagation process. In some mathematical models, the derivation of physical parameters is required to fit time history and response spectrum of the simulated record to the actual record through trial and error process, which limits the scope of these models. In the current study, the particle swarm optimization (PSO) algorithm is replaced with the trial and error procedure. In this way, an automatic and quantitative process with the minimal judgment of the analyst is prepared to extract a wide range of Pulselike records. Then, the proposed approach is applied to simulate and represent mathematically a set of 91 Pulselike records from the Next Generation Attenuation (NGA) project ground motion library. The obtained results show that a velocity Pulse of each Pulselike record could be extracted using the proposed approach, and it can therefore be considered as a powerful tool in Pulse parametric studies and the relationship between velocity Pulse and structure’ s response.

Background and Objectives: Dielectric Barrier discharge (DBD) is a suitable method to generating Non-thermal plasma at atmospheric pressure, which utilizes Pulsed power supplies as exciters. Increasing Pulse voltage range and frequency and compactness are important issues that should be taking into consideration. Methods: The high voltage Pulse generators which are introduced in the literature have some disadvantages and complexities such as need of additional winding to reset the transformer core and operating under hard switching which increases electromagnetic noise and loss. The leakage inductance of the high voltage transformer increases the rise time of the Pulse which is undesirable for DBD applications. The energy stored in the leakage inductance causes the voltage spike across the switch, witch necessitates the use of snubber circuits. The main contribution of this paper is a new high voltage Pulse generator with the following characteristics, 1) a capacitor is paralleled with the main switch to reset the transformer core and to provide the soft switching condition for the switch. 2) The resonant charging technique is used which doubles the secondary winding voltage which reduces the turns ratio of high voltage transformer for a certain output Pulse peak. 3) The sharpening circuit using magnetic switch produces a sharp high voltage Pulse. Results: The proposed high voltage Pulse generator is designed and simulated using Pspice software. To verify the theoretical results, a prototype with the input voltage 48 V, the output voltage Pulse 1. 5 kV, and the rise time of the output Pulse 50 ns is constructed and tested. Conclusion: This paper proposes a new Pulse generator (PG). The proposed PG uses three techniques named forward, resonant charging, and magnetic switch to produce a high-voltage nanosecond Pulse. The resonant charging double the secondary voltage of the Pulse transformer, which causes reduction in turn ratio of the Pulse transformer and decreases the weigh, volume, and price of the PT. The magnetic switch section finally produces a nanosecond high-voltage Pulse. The magnitude of the output Pulse can be varied using the input source voltage, the MS reset current and the duty cycle. The core of the Pulse transformer resets by using a capacitor paralleled with the switch and the PG does not need any additional reset winding like the conventional DC-DC forward converter.