With the improvement of radar digitization, digitalarrayradar (DAR) has been widely researched in the radar industry . In order to further improve the resource utilization ratio of the radar system, pulse interleaving technology is proposed. Orman analyzed this method in  and proposed the heuristic algorithm to solve the problem of adaptive beam-dwell scheduling for phased arrayradar. Aiming at the problem of beam-dwell scheduling for DAR, an algorithm based on analyzing scheduling interval is proposed in . However, in almost all existing adaptive resource scheduling methods for DAR, the imaging mission is not taken into account. Joint scheduling imaging tasks with search, tracking and other tasks can not only improve the recognition ability of the radar to the target, but also feedback the target characteristic information obtained by the image to the transmitter radar system, so as to realize the dynamic adjustment of imaging tasks and improve resource utilization radio . Traditional imaging algorithm require continuous observation of targets for a long time to obtain high-resolution images, but the alternation of different tasks inevitably leads to discontinuous synthetic aperture sampling of the imaging target azimuth.
Abstract—Wideband digital beamforming (WDBF) technology is a key for the rapidly developing wideband digitalarrayradar (WDAR). In this paper, by comprehensively considering the characteristics of WDAR and the current hardware and software capabilities for radar in engineering, several practical WDBF technologies based on accurate digital true time delay (TTD) are studied. WDBF technology at radio frequency (RF) is applied and tested on a WDAR test-bed. Besides, WDBF technologies at baseband by implementing fractional delay ﬁlers at element level and subarray level are presented and simulated.
A new radar concept, the opportunistic arrayradar (OAR) which is also called distributed phased arrayradar, has been proposed by some scholars in recent years [Jenn and Loke, 2009; Long et al., 2009; Gong et al., 2013], based on digitalarrayradar. OAR is a new radar system based on the stealth of the platform, which can improve the modern radar performance effectively. The array elements of opportunistic arrayradar are dis- tributed randomly in the aircraft or ship platform. The beamforming data, control signals, and target return signals are sent wirelessly between the transmit/receive modules, where the beamformer and signal proces- sor are located away from the modules. The concept, principle, and characteristics of the opportunistic digitalarrayradar are presented in Long et al. . Phase orthogonal code sets with low autocorrelation and cross- correlation properties, which can be used in the OAR systems, are reported in Gong et al. . But the research of the OAR is still at the beginning, for example, there are very few studies on the radiation control of the OAR network.
(or received) by a phased array.Pozar  explained the blindness mechanism as a forced surface wave and at scan-blindness, the input impedance of any printed element in the array has a zero real part and a very large reactive part, so the antenna elements are eﬀectively open- circuit.In Equation (6), AF (θ) will decrease sharply if the will add up in phase causing a null in the active element pattern resulting in the so called blind-angle phenomena.On the other side, it has been demonstrated that the surface wave, part of mutual coupling, plays a major role in the scattering behavior of microstrip printed dipoles .So, it is very important to compensate the term C mn of
In this section, the particle swarm optimization (PSO) is modified and applied to the CPPAR antenna to obtain the radiation pattern with the desired sidelobe levels (SLL). Particle swarm optimization simulates the behaviors of bird flocking [16–18]. In this algorithm, a group of birds is randomly searching for food in the specific area. There is only one piece of food in the area being searched [10, 19]. Although all the birds do not know where the food is, they know their distance to the food, in each step. In our case, one set of beamforming weight w in Eq. (4) represents a particle for the optimization problem. The distance of the array radiation pattern to desired radiation pattern (i.e., mask) for each w is defined as the distance of the particle to the food or the fitness value. Thus, the best strategy to find the food or optimal value is to follow the bird which is nearest to the food. PSO is learning from the scenario and updating particles to solve the optimization problem. In this algorithm, every single solution is considered as a particle in the solution space. All the particles have fitness values which are evaluated by the optimal value and have velocities which direct the flying of the particles to the food. The particles follow the current optimum particle (or local best) and fly through the problem space to find the global optimal value (or global best). Consider 2N variables as the phase and amplitude of N element patterns for the optimization. Each particle is assigned a random position in the 2N -dimensional problem space and represents one set of beamforming weights. Therefore, each particle’s position is corresponding to a candidate solution of the optimization problem, and these particle positions are scored to calculate a cost based on how well each particle solves the problem. By using a simple update rule, these particles then fly to new positions in the problem space, which are then mapped to the problem space and scored in new positions.
The most abundant source of radar scatter comes from the ionization electrons that are produced by the energetic air shower particles as they traverse the atmosphere. These ionization electrons constitute a plasma, which can in principle reflect electromagnetic waves. Following Gorham , we can divide an air shower into two regions, depending on whether the ionization density exceeds the critical density at which the plasma frequency 
It has been recently shown that multiple-input multiple-output (MIMO) [1, 2] antenna systems have the potential to dramatically improve the performance of communication systems over single antenna systems. Unlike beam forming, which presumes a high correlation between signals either transmitted or received by an array, the MIMO concept exploits the independence between signals at the array elements. In conventional radar, target scintillations are regarded as a nuisance parameter that degrades radar performance. The novelty of MIMO radar is that it takes the opposite view, namely, it capitalizes on target scintillations to improve the radar’s performance. The MIMO radar system under consideration consists of a transmit array with widely-spaced elements such that each views a diﬀerent aspect of the target. It can overcome target RCS scintillations by transmitting diﬀerent signals from several decor related transmitters. The received signal is a superposition of independently faded signals, and the average SNR of the received signal is more or less constant. This is in marked contrast to conventional radar, which under classical Swelling models suﬀers from large variations in the received power. Therefore the objectives of MIMO radar are the target resolution should have the higher as compared to conventional radar. Interference and clutter rejection should be the highest, RCS measurement accuracy should be the highest and multi-path and other environmental eﬀects should be the minimum. But unfortunately MIMO technology alone cannot tackle all the problems solution.
instantaneously mixed noisy signal. The difference between the desired target signals in radar echo and its transmitted signals mostly lies on time delay and frequency slide, and thus the AR model parameters of the desired target signals can be estimated using the transmitted signals. According to the above analysis, our novel algorithm in noisy case can be applied to extract the desired target signals received by arrayradar [15-18] for increasing the detection ability of arrayradar under the jamming interference environment.
The first stage, Figure 7, represents the ponds Tau area), it shows a flat region without much distor- sions.Only remain, those from the radar geometry in the SAR mode, but not reversals due to reliefs. In this case, the radar and SPOT geometries are similar, in addition, the site has special features points that can be selected as landmarks: Cape border of cultivated plots, contour of the pond. A possible application could be followed in real time by satellite, drift oyster beds. Indeed, the image that we present shows the overlap between radar data and SPOT data. , The park oysters, submerged do not appear on the SPOT image, however, are clearly visible on the radar image.
target based on the standard ULA FDA. In this paper, we devise a sub-array scheme on FDA radar for range and angle estimation. The essence is to divide the FDA elements into two sub-arrays, which offer decoupled range and angle responses and target positions can be estimated by the subspace-based algorithm (Root-MUSIC and TLS-ESPRIT). In order to aperture extension, difference co-array is employed in each sub--arrays, and more targets can be distinguished than the physical sensors. The numerical simulation results show that a satisfactory estimation performance can be got. The derived CRLB also can be used to optimally design the sub-array frequency shifts.
new waveform designs are sought after. The waveform design should satisfy a number of requirements that depend on the application and the nature of noise or clutter exists. However, correlation between the transmitted and received signals can be used instead of matched filtering. When a correlator is used, the delay to is essential to be synchronized so as to obtain the maximum SNR, while it is not critical in a MF. Matched filter is active in the presence of white noise rather than colored-noise. Therefore in presence of colored-noise, a whitening filter has to be applied prior to the matched filter or correlator, in order to alter the spectrum of noise and avoid mismatch with the signal. Integration is a class of matched filtering techniques that is used in Radar Signal Processing (RSP) in order to enhance the SNR of the received echo signal. The integrator accumulates the energy of subsequent echo pulses that are reflected by the same target. On the other hand, noise signals are not correlated and thus their integrated energy tends to vanish, and hence the SNR at the output of the integrator is going to increase. Predetection integration takes place within the IF stage of the receiver, realizing better SNR compared to post-detection integration
in the PPI format. The Standard set of signals required areSync Pulse, Antenna Change Pulse, Video Pulseand Heading Marker Pulse. First of all Sync Pulse iscoming. The function of Sync Pulse to generate the beamon the PPI. After that Antenna Change Pulse is required to rotatethe beam appearing on the PPI. Video Pulse has animportant role because targets which is appearing on thePPI is depending on the video Pulse if video Pulse is notcoming then Targets will not be appeared . To meet therequirements of testing of Radar Display, thissimulator is generating Video, Heading, Sync, and Antenna Change Pulses.
In this paper, the implementation of DSP algorithms on FPGA devices are taken into consideration and the FFT spectral analysis as a real time application was tested in MATLAB System Generator. It integrates two separate fields Digital Signal Processing (DSP) and Very Large Scale Integration (VLSI). The structure and chronological procedure followed focuses on the sophisticated DSP design and implementation of a Fast Fourier Transform (FFT) spectrum analyzer. The entire system was implemented in MATLAB Simulink Xilinx System generator (SG) toolbox. After simulation, the verilog coding was extracted and implemented on FPGA Virtex II device. As a part of betterment, FIR filter of the analyzer was replaced with Goertzel filter in order to improve the area efficiency of the FPGA device. It provides better frequency resolution and helps in extracting the amplitude component of the signal, thus aiding in improved spectral analysis.
TWR designs have followed both time (impulse) and frequency domain (FMCW) waveform approaches. Impulse radar works in the time domain  and obtains high range resolution by transmitting a wide band impulse which means the pulse width will be in the order of few nano seconds. The disadvantage with this method is the requirement of high sampling rates and complex hardware design. The frequency domain approach such as Frequency Modulated Continuous Wave (FMCW) and SFCW works on generating the required bandwidth by means of modulating the transmitted wave.
In this paper, we focus on the application of the target detection performance  of Phased arrayradar over conventional MIMO radar -. Consider two radar scenarios: a phased array, where the same waveform is transmitted from each antenna; and orthogonal multiple-input–multiple- output (MIMO) radar , whereby independent waveforms are transmitted from each antenna. A major benefit of phased arrayradar is the increment of signal power incident on the target due to beam forming gain; whereas the coherent MIMO radar ,  cannot beam form on transmit resulting in a comparative reduction in SNR. Scaled versions of a single waveform are transmitted by phased-arrayradar antennas. By adjusting the phase at each antenna results in a concentrated narrow beam of energy onto a scene of interest. The similarities and differences of these radar systems are explored. Detection performances of MIMO radars and phased arrayradar are compared through numerical simulations by providing the detectors.
As for the environmental monitoring-based systems, typically used sensors such as cameras acoustic sensors (e.g., microphone array), radar and infrared sensors, pressure sensors, or accelerometer for vibration detection are placed in a predefined space or environment to monitor the activities of the elderly as well as the occurrence of a fall accident event. Compared to the type of wearable sensor-based system, the environmental monitoring-based fall detection system is more comfortable to the elderly since there is no need of wearing any module. However, the environmental monitoring-based system can only function in a predefined environment where it is installed. Moreover, the protection of the private matters for the elderly is another problem and contention is usually discussed with the environmental monitoring-based system.
Abstract This paper presents a hierarchical sensor fusion approach for human micro-gesture recognition by combining an Ultra Wide Band (UWB) Doppler radar and wearable pressure sensors. First, the wrist-worn pressure sensor array (PSA) and Doppler radar are used to respectively identify static and dynamic gestures through a Quadratic-kernel SVM (Support Vector Machine) classifier. Then, a robust wrapper method is applied on the features from both sensors to search the optimal combination. Subsequently, two hierarchical approaches where one sensor acts as “enhancer” of the other are explored. In the first case, scores from Doppler radar related to the confidence level of its classifier and the prediction label corresponding to the posterior probabilities are utilized to maximize the static hand gestures classification performance by hierarchical combination with PSA data. In the second case, the PSA acts as an ‘Enhancer’ for radar to improve the dynamic gesture recognition. In this regard, different weights of the ‘Enhancer’ sensor in the fusion process have been evaluated and compared in terms of classification accuracy. A realistic cross-validation method is chosen to test one unknown participant with the model trained by data from others, demonstrating that this hierarchical fusion approach for static and dynamic gestures yields approximately 15% improvement in classification accuracy in the best cases.
сharaсterization of dual band and 1×4 dual band antenna array on a flexible polymide substrate. In this paper we have presented the design of a dual band miсrostrip antenna which will be operating in the wireless LAN band and IEEE 802.11 a/b/g. Dual-band antenna elements that support dual- polarization provide ideal performance for applications including space-based platforms, multifunction radar, wireless сommuniсations, and personal eleсtroniс deviсes. In many сommuniсations and radar appliсations, a dual-band, dual- polarization antenna array beсomes a requirement in order to produсe an eleсtroniсally steerable, direсtional beam сapable of supporting multiple funсtions. In this paper a dual band miсrostrip antenna is designed and its measurement results in terms of S(1,1) parameters and radiation patterns are studied. Miсrostrip design equations are introduсed and validated by simulated results. This antenna is implemented on polymide substrate with ε r = 4.3, h=1.6 mm and operating frequenсy 5.25