scholarly journals A Novel Transmit–Receive System of Frequency Diverse Array Radar for Multitarget Localization

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 408 ◽  
Author(s):  
Shengbin Luo Wang ◽  
Zhen-hai Xu ◽  
Xinghua Liu ◽  
Wei Dong ◽  
Guoyu Wang
Keyword(s):  
Lower Bound ◽  
System Performance ◽  
Pulse Beam ◽  
System Framework ◽  
Single Target ◽  
Full Band ◽  
Receive System ◽  
Frequency Diverse Array ◽  
Simulation Results ◽  
Proper Frequency

The frequency diverse array (FDA) has drawn substantial attention because it provides a new degree of freedom. However, the multitarget localization is fundamentally limited by the range-angle-coupled and range-periodic beampattern of the basic FDA. It has been suggested to design a special FDA configuration to localize targets, but seldom of the existing works consider the design both in transmitting and receiving. In this paper, a transmit–receive system of FDA radar is proposed for the multitarget localization. In order to decouple the beampattern in the range and angle domains, the configurations of subarray-based FDA (SB-FDA) and full-band FDA (FB-FDA) are chosen as transmitter and receiver, respectively. In such a system framework, the receive beamwidth in range domain is only a quarter of the transmission. Then, two typical multitarget scenarios, sparse targets and unresolved targets, are both considered in the multitarget localization. For sparse targets, a proper frequency increment is selected to control the range-periodic transmit and receive mainlobes to focus on a single target, besides being staggered with others. In this way, multitarget localization is achieved in different pulses with monopulse processing. For unresolved targets, a method of intra-pulse beam scanning is proposed to localize each target with little interference from others. We also analyze the system performance in Cramér-Rao lower bound (CRLB) of localization and output signal to interference-plus-noise ratio (SINR). Several simulation results demonstrate the effectiveness of the proposed transmit–receive system in multitarget localization.

scholarly journals Ground Target Tracking Using an Airborne Angle-Only Sensor with Terrain Uncertainty and Sensor Biases

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 509
Author(s):  
Dipayan Mitra ◽  
Aranee Balachandran ◽  
Ratnasingham Tharmarasa
Keyword(s):  
Lower Bound ◽  
Estimation Error ◽  
Common Source ◽  
Bias Estimation ◽  
Tracking Accuracy ◽  
Digital Terrain ◽  
Single Target ◽  
Elevation Data ◽  
Measurement Biases ◽  
Terrain Elevation

Airborne angle-only sensors can be used to track stationary or mobile ground targets. In order to make the problem observable in 3-dimensions (3-D), the height of the target (i.e., the height of the terrain) from the sea-level is needed to be known. In most of the existing works, the terrain height is assumed to be known accurately. However, the terrain height is usually obtained from Digital Terrain Elevation Data (DTED), which has different resolution levels. Ignoring the terrain height uncertainty in a tracking algorithm will lead to a bias in the estimated states. In addition to the terrain uncertainty, another common source of uncertainty in angle-only sensors is the sensor biases. Both these uncertainties must be handled properly to obtain better tracking accuracy. In this paper, we propose algorithms to estimate the sensor biases with the target(s) of opportunity and algorithms to track targets with terrain and sensor bias uncertainties. Sensor bias uncertainties can be reduced by estimating the biases using the measurements from the target(s) of opportunity with known horizontal positions. This step can be an optional step in an angle-only tracking problem. In this work, we have proposed algorithms to pick optimal targets of opportunity to obtain better bias estimation and algorithms to estimate the biases with the selected target(s) of opportunity. Finally, we provide a filtering framework to track the targets with terrain and bias uncertainties. The Posterior Cramer–Rao Lower Bound (PCRLB), which provides the lower bound on achievable estimation error, is derived for the single target filtering with an angle-only sensor with terrain uncertainty and measurement biases. The effectiveness of the proposed algorithms is verified by Monte Carlo simulations. The simulation results show that sensor biases can be estimated accurately using the target(s) of opportunity and the tracking accuracies of the targets can be improved significantly using the proposed algorithms when the terrain and bias uncertainties are present.

scholarly journals Comparative Analysis and Design of the Shielding Techniques in WPT Systems for Charging EVs

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2115 ◽  
Author(s):  
Linlin Tan ◽  
Kamal Eldin Idris Elnail ◽  
Minghao Ju ◽  
Xueliang Huang
Keyword(s):  
Finite Element Method ◽  
Electric Vehicles ◽  
System Performance ◽  
Human Exposure ◽  
System Efficiency ◽  
Shielding Effectiveness ◽  
Wireless Power ◽  
Analysis And Design ◽  
Reactive Current ◽  
Simulation Results

Wireless power transfer (WPT) systems for charging Electric Vehicles (EVs) have gained extensive attention due to their many advantages. However, human exposure to electromagnetic fields (EMFs) has become a serious concern in high-power cases. In this paper, shielding techniques, including magnetic, metallic, and resonant reactive current shields, are investigated. Finite element method software is used to evaluate and compare the shielding effectiveness, charger weight, and system performance. The results show that the resonant reactive current shielding has a low EMF level with reasonable system efficiency and acceptable charger weight. In addition, 5 kW with 15 cm air gap WPT chargers were built to validate the simulation results.

scholarly journals Channel Estimation for OFDM-Based Amplify-and-Forward Cooperative System Using Relay-Superimposed Pilots

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Xianwen He ◽  
Gaoqi Dou ◽  
Jun Gao
Keyword(s):  
Lower Bound ◽  
Channel Estimation ◽  
Data Stream ◽  
Direct Link ◽  
Frequency Division ◽  
Cooperative System ◽  
Amplify And Forward ◽  
System A ◽  
Pilot Symbols ◽  
Simulation Results

For the OFDM-based Amplify-and-Forward cooperative system, a novel relay-superimposed pilot strategy is proposed, where the source pilot symbols are frequency division multiplexed to estimate the cascaded channel while relay pilot sequence is superimposed onto the top of the cooperative data stream for second-hop channel estimation. This method avoids the loss of data rate for additional pilot subcarriers but results in the interference of unknown cooperative data. To remove the interference of cooperative data during the estimation of second-hop channel, the Cooperative Interference Cancelation scheme assisted by cooperative data from direct link is proposed. We derive the approximated lower bound for the MSE of second-hop channel estimation. Simulation results are presented to validate the performance of the proposed schemes.

Performance Comparison of LS and LMMSE Channel Estimation Algorithm for CO-OFDM System

2011 ◽  
Vol 130-134 ◽  
pp. 2965-2968
Author(s):  
Zheng Rong Tong ◽  
Min Jie Guo ◽  
Xiu Feng Yang ◽  
Wei Hua Zhang
Keyword(s):  
Optical Fiber ◽  
Bit Error Rate ◽  
System Performance ◽  
Single Mode ◽  
Estimation Algorithm ◽  
Performance Comparison ◽  
Ofdm System ◽  
Fiber System ◽  
Single Mode Optical Fiber ◽  
Simulation Results

The CO-OFDM single-mode optical fiber system is constructed by the Matlab coupled with the Optisystem. And the influence of different channel algorithm on the receiver of system is researched. The simulation results show that the system performance is improved by using LS or LMMSE channel algorithm. And the LMMSE channel algorithm can provide better performance than the LS channel algorithm. Compared with LS algorithm, the required receiver OSNR is reduced by about 1 dB using improved LMMSE algorithm at bit-error-rate (BER) =10-4 in the CO-OFDM single-mode optical fiber system.

scholarly journals Research on Multi-Target Scales Estimation Based on the Theory of Fuzzy Clustering

2012 ◽  
Vol 6-7 ◽  
pp. 561-565
Author(s):  
Bai He Wang ◽  
Dai Zhi Liu ◽  
Shi Qi Huang
Keyword(s):  
Fuzzy Clustering ◽  
Clustering Analysis ◽  
Target Identification ◽  
Scale Estimation ◽  
Fuzzy Clustering Analysis ◽  
Single Target ◽  
Shortest Distance ◽  
Effective Technology ◽  
Simulation Results ◽  
Underwater Target

Scale recognition is the effective technology in underwater target identification. The existing methods can only solve the problem of single-target scale estimation and are not adaptable to the problem of multi-target scale estimation and recognition in complex counterwork. A method named FC based on fuzzy clustering analysis was put forward to analyze and estimate the multi-target scales in this paper. In the method, all the highlights collected by homing system were analyzed by dynamic fuzzy clustering with the principle of shortest distance, and scales were estimated separately based on the lights belonged to deferent sorts. Simulation results show that the problem of multi-target scale recognition can be solved effectively with FC method.

SIMULATIONS OF UNARY ONE-WAY MULTI-HEAD FINITE AUTOMATA

2014 ◽  
Vol 25 (07) ◽  
pp. 877-896 ◽  
Author(s):  
MARTIN KUTRIB ◽  
ANDREAS MALCHER ◽  
MATTHIAS WENDLANDT
Keyword(s):  
Lower Bound ◽  
Lower Bounds ◽  
Finite Automaton ◽  
Finite Automata ◽  
Upper And Lower Bounds ◽  
Unary Languages ◽  
Order Of Magnitude ◽  
Simulation Results ◽  
Special Case ◽  
Nondeterministic Finite Automaton

We investigate the descriptional complexity of deterministic one-way multi-head finite automata accepting unary languages. It is known that in this case the languages accepted are regular. Thus, we study the increase of the number of states when an n-state k-head finite automaton is simulated by a classical (one-head) deterministic or nondeterministic finite automaton. In the former case upper and lower bounds that are tight in the order of magnitude are shown. For the latter case we obtain an upper bound of O(n2k) and a lower bound of Ω(nk) states. We investigate also the costs for the conversion of one-head nondeterministic finite automata to deterministic k-head finite automata, that is, we trade nondeterminism for heads. In addition, we study how the conversion costs vary in the special case of finite and, in particular, of singleton unary lanuages. Finally, as an application of the simulation results, we show that decidability problems for unary deterministic k-head finite automata such as emptiness or equivalence are LOGSPACE-complete.

A Novel VoIP Scheduling Algorithm in IEEE 802.16e System

2010 ◽  
Vol 439-440 ◽  
pp. 1463-1468
Author(s):  
Xiang Xian Zhu ◽  
Xiu Ying Sun ◽  
Qi Feng Sun
Keyword(s):  
System Performance ◽  
Scheduling Algorithm ◽  
Voice Over Ip ◽  
Ieee 802.16E ◽  
Service Flow ◽  
Simulation Results ◽  
Special Algorithm

In IEEE 802.16e network, voice over IP (VoIP) scheduling is critical to system performance but no special algorithm is defined in the IEEE 802.16e standard. Based on this thinking, a novel VoIP scheduling algorithm named compensated based VoIP scheduling (CBVS) is proposed. This algorithm compensates the bandwidth of service flow whose bandwidth is lost using the remained bandwidth. The simulation results show that the proposed algorithm improves the performance much and increases the number of VoIP users.

scholarly journals CRYSTAL COLLIMATION STUDIES AT THE TEVATRON (T-980)

2010 ◽  
Vol 25 (supp01) ◽  
pp. 98-105 ◽  
Author(s):  
N.V. MOKHOV ◽  
G.E. ANNALA ◽  
A. APYAN ◽  
R.A. CARRIGAN ◽  
A.I. DROZHDIN ◽  
...  
Keyword(s):  
Proton Beam ◽  
System Performance ◽  
Superconducting Magnets ◽  
Silicon Crystal ◽  
High Energy ◽  
Experimental Setup ◽  
Beam Diagnostics ◽  
Bent Crystal ◽  
Beam Halo ◽  
Simulation Results

Bent-crystal channeling is a technique with a potential to increase beam-halo collimation efficiency in high-energy colliders. First measurements at the Tevatron in 2005 have shown that using a thin silicon crystal to deflect the 1-TeV proton beam halo onto a secondary collimator improves the system performance by reducing the machine impedance, beam losses in the collider detectors and irradiation of the superconducting magnets, all in agreement with simulations. Recent results, obtained with an improved goniometer and enhanced beam diagnostics, are reported here for dedicated beam studies and first full collider stores along with simulation results and plans for substantial enhancement of the T-980 experimental setup.

AN EMPIRICAL STUDY OF HIERARCHICAL DIVISION FOR MESH-STRUCTURED NETWORKS

2007 ◽  
Vol 08 (03) ◽  
pp. 285-304
Author(s):  
DAJIN WANG
Keyword(s):  
Data Aggregation ◽  
System Performance ◽  
Network Routing ◽  
Distributed Monitoring ◽  
Network Loading ◽  
Distributed Processes ◽  
Multi Level ◽  
Simulation Results ◽  
Multiple Levels ◽  
Hypercube Networks

A parallel/distributed system consists of a collection of processes, which are distributed over a network of processors, and work in a cooperative manner to fulfill various tasks. A hierarchical approach is to group and organize the distributed processes into a logical hierarchy of multiple levels to achieve better system performance. It has been proposed as an effective way to solve various problems in distributed computing, such as distributed monitoring, resource scheduling, and network routing. In [21], we studied hierarchical configuration for mesh and hypercube networks to the end of achieving better system performance. In particular, we proposed theoretically optimal hierarchy for mesh and hypercube, so that the total traffic flow over the network is minimized. In this paper, we present the experimental results to establish the practical relevance of mesh hierarchy proposed in [21]. We simulated situations for multi-level division, real network loading scenarios, random data aggregation rates, and different division sizes other than derived in [21]. The simulation results not only show that the analytically obtained hierarchy works well for many realistic settings, but also offer some useful insights into the proposed hierarchy scheme.

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