scholarly journals Phasing errors of the matrix simulator of the echo signals of the multi-antenna radar system

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
M.A. Stepanov ◽  
◽  
T.I. Sabitov ◽  
A.V. Kiselev
Keyword(s):  
Phase Error ◽  
Antenna System ◽  
Maximum Phase ◽  
Worst Case ◽  
Phase Errors ◽  
Radar Systems ◽  
The Matrix ◽  
Simulation Errors ◽  
Theoretical Results ◽  
Receive Antenna

This work is devoted to the study of phasing errors of a matrix simulator focused on several receiving points. Errors arising during signal calibration are considered. The phase error compensation procedure is designed for matrix simulators used to simulate echoes for a single receive antenna. It allows to align the phases of the simulator signals and eliminate simulation errors caused by phase errors. It is shown that this procedure does not allow to eliminate phasing errors simultaneously for several receiving antennas. The case of a two-antenna system and a matrix of two emitters is considered. For this case, a relation was obtained for calculating the phase correction, which minimizes the phasing error of the signals. Herewith the magnitude of the error depends on the magnitude of the random displacements of the emitters from the required positions. For a given emitter positioning accuracy, the worst case is investigated, which corresponds to the maximum phase error. Relationships are obtained to estimate this error. On the basis of these relations, the ways of its minimization are established. For a larger number of emitters, a relation is obtained for calculating the maximum possible phasing error. The results obtained can be extended to the case of a larger number of receiving antennas. In order to verify the theoretical results a matrix of two emitters was developed focused on two receiving points. A number of numerical experiments have been carried out, the results of which have confirmed the reliability of the obtained relationships. The results of this work are practically significant, since they determine the requirements for the configuration of the matrix simulator. They allow to determine whether the required phasing can be provided for a given matrix. They can be used in the development of matrix simulators of echo signals of multi-antenna radar systems.

EVALUATION AND COMPENSATION OF SYSTEMATIC ERRORS OF CALIBRATION OF MATRIX SIMULATOR

2018 ◽  
pp. 24-28
Author(s):  
A. V. Kiselev ◽  
A. O. Podkopaev ◽  
M. A. Stepanov
Keyword(s):  
Phase Error ◽  
Precise Determination ◽  
Random Component ◽  
Compensation Error ◽  
The Matrix ◽  
Calibration Algorithm ◽  
Phase Calibration ◽  
Analytical Relations ◽  
Theoretical Results

The problem of phase calibration of the matrix simulator is considered. The phase error at the point of reception is divided into systematic and random. Analytic relationships are obtained that allow one to evaluate and compensate for the systematic error in the calibration of the phases of the signals emitted by the matrix simulator, caused by the geometric separation of the phase centers of the antenna and the antenna of the calibration receiver. The random component of the phase error is compensated by the calibration algorithm. Analytical relations are obtained for determining the compensation error due to the non-precise determination of the coordinates of the emitting part of the matrix simulator and the phase center of the antenna of the measuring receiver. The magnitude of this error is determined for the typical location of the antennas of the device under investigation, the measuring receiver and the matrix simulator when performing semi-realistic simulation. The description of the laboratory stand of the developer of the matrix imitator is given. The obtained theoretical results are confirmed experimentally at the booth of the matrix imitator developer.

scholarly journals A Review on the Development of Rotman Lens Antenna

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Shruti Vashist ◽  
M. K. Soni ◽  
P. K. Singhal
Keyword(s):  
High Performance ◽  
Beam Steering ◽  
Phase Error ◽  
Antenna System ◽  
Surveillance Systems ◽  
Electronic Warfare ◽  
Design Concepts ◽  
Low Profile ◽  
True Time ◽  
The One

Rotman lenses are the beguiling devices used by the beamforming networks (BFNs). These lenses are generally used in the radar surveillance systems to see targets in multiple directions due to its multibeam capability without physically moving the antenna system. Now a days these lenses are being integrated into many radars and electronic warfare systems around the world. The antenna should be capable of producing multiple beams which can be steered without changing the orientation of the antenna. Microwave lenses are the one who support low-phase error, wideband, and wide-angle scanning. They are the true time delay (TTD) devices producing frequency independent beam steering. The emerging printed lenses in recent years have facilitated the advancement of designing high performance but low-profile, light-weight, and small-size and networks (BFNs). This paper will review and analyze various design concepts used over the years to improve the scanning capability of the lens developed by various researchers.

scholarly journals Study of the Readability of Passive UHF RFID Tags Placed Inside a Cargo Van by a Reader Located Outside

2014 ◽  
Vol 10 (2) ◽  
pp. 76
Author(s):  
Philippe Mariage ◽  
M.M. Handeme Nguema ◽  
Laurent Clavier
Keyword(s):  
Low Cost ◽  
Software Tool ◽  
Antenna System ◽  
Uhf Rfid ◽  
Passive Uhf Rfid ◽  
Passive Tags ◽  
Whole Space ◽  
Storage Area ◽  
Semi Empirical ◽  
Theoretical Results

The aim of this paper is to study the feasibility of getting information from a cargo van returning back on its storage area by using a low cost communication system. According to the low speed of the vehicle and to the involved short distances, a UHF RFID solution is considered. An experimental study shows that passive tags may be read successfully but not in the entire space of the van. A semi-empirical numerical method based on the Geometrical Optics is derived in order to build a fast computer aided-positioning tool that may help to optimize the location of the tags. The same software tool is used for carrying out a parametric study that informs on the best antenna system to use. It is find out that a solution using passive tags and two antennas limits the theoretical results to 90% successful reading percentage whereas using semi-passive tags ensures a 100% one in the whole space of the vehicle.

scholarly journals Conducting Non-Adaptive Experiments in a Live Setting: A Bayesian Approach to Determining Optimal Sample Size

2019 ◽  
Author(s):  
Nandan Sudarsanam ◽  
Ramya Chandran ◽  
Daniel D. Frey
Keyword(s):  
Statistical Learning ◽  
Optimal Allocation ◽  
Analytical Techniques ◽  
Optimal Level ◽  
Base Case ◽  
Allocation Of Resources ◽  
Worst Case ◽  
Optimal Sample Size ◽  
Optimal Sample ◽  
Theoretical Results

Abstract This research studies the use of predetermined experimental plans in a live setting with a finite implementation horizon. In this context, we seek to determine the optimal experimental budget in different environments using a Bayesian framework. We derive theoretical results on the optimal allocation of resources to treatments with the objective of minimizing cumulative regret, a metric commonly used in online statistical learning. Our base case studies a setting with two treatments assuming Gaussian priors for the treatment means and noise distributions. We extend our study through analytical and semi-analytical techniques which explore worst-case bounds and the generalization to k treatments. We determine theoretical limits for the experimental budget across all possible scenarios. The optimal level of experimentation that is recommended by this study varies extensively and depends on the experimental environment as well as the number of available units. This highlights the importance of such an approach which incorporates these factors to determine the budget.

scholarly journals Strip-Mode Microwave Staring Correlated Imaging with Self-Calibration of Gain–Phase Errors

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1079 ◽  
Author(s):  
Rui Xia ◽  
Yuanyue Guo ◽  
Weidong Chen ◽  
Dongjin Wang
Keyword(s):  
Error Estimation ◽  
Phase Error ◽  
Super Resolution ◽  
Image Splicing ◽  
Initial Value ◽  
Self Calibration ◽  
Phase Errors ◽  
Imaging Model ◽  
Multiple Imaging ◽  
Imaging Performance

Microwave staring correlated imaging (MSCI) can realize super resolution imaging without the limit of relative motion with the target. However, gain–phase errors generally exist in the multi-transmitter array, which results in imaging model mismatch and degrades the imaging performance considerably. In order to solve the problem of MSCI with gain–phase error in a large scene, a method of MSCI with strip-mode self-calibration of gain–phase errors is proposed. The method divides the whole imaging scene into multiple imaging strips, then the strip target scattering coefficient and the gain–phase errors are combined into a multi-parameter optimization problem that can be solved by alternate iteration, and the error estimation results of the previous strip can be carried into the next strip as the initial value. All strips are processed in multiple rounds, and the gain–phase error estimation results of the last strip can be taken as the initial value and substituted into the first strip for the correlated processing of the next round. Finally, the whole imaging in a large scene can be achieved by multi-strip image splicing. Numerical simulations validate its potential advantages to shorten the imaging time dramatically and improve the imaging and gain–phase error estimation performance.

scholarly journals Generalized Inverses Estimations by Means of Iterative Methods with Memory

Mathematics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 2
Author(s):  
Santiago Artidiello ◽  
Alicia Cordero ◽  
Juan R. Torregrosa ◽  
María P. Vassileva
Keyword(s):  
Iterative Methods ◽  
Generalized Inverses ◽  
Drazin Inverse ◽  
Nonsingular Matrix ◽  
Type Method ◽  
The Matrix ◽  
Nonlinear Matrix ◽  
First Time ◽  
With Memory ◽  
Theoretical Results

A secant-type method is designed for approximating the inverse and some generalized inverses of a complex matrix A. For a nonsingular matrix, the proposed method gives us an approximation of the inverse and, when the matrix is singular, an approximation of the Moore–Penrose inverse and Drazin inverse are obtained. The convergence and the order of convergence is presented in each case. Some numerical tests allowed us to confirm the theoretical results and to compare the performance of our method with other known ones. With these results, the iterative methods with memory appear for the first time for estimating the solution of a nonlinear matrix equations.

Multiconsensus of first-order multiagent systems with directed topologies

2020 ◽  
Vol 34 (23) ◽  
pp. 2050240
Author(s):  
Xiao-Wen Zhao ◽  
Guangsong Han ◽  
Qiang Lai ◽  
Dandan Yue
Keyword(s):  
Multiagent Systems ◽  
Matrix Theory ◽  
Sufficient Conditions ◽  
Consensus Problem ◽  
Multiple Agents ◽  
First Order ◽  
The Matrix ◽  
Directed Topologies ◽  
Necessary And Sufficient ◽  
Theoretical Results

The multiconsensus problem of first-order multiagent systems with directed topologies is studied. A novel consensus problem is introduced in multiagent systems — multiconsensus. The states of multiple agents in each subnetwork asymptotically converge to an individual consistent value in the presence of information exchanges among subnetworks. Linear multiconsensus protocols are proposed to solve the multiconsensus problem, and the matrix corresponding to the protocol is designed. Necessary and sufficient conditions are derived based on matrix theory, under which the stationary multiconsensus and dynamic multiconsensus can be reached. Simulations are provided to demonstrate the effectiveness of the theoretical results.

scholarly journals Radio Interference in Astronomical Observatories of China

2001 ◽  
Vol 196 ◽  
pp. 307-310
Author(s):  
B. Peng ◽  
R. Nan ◽  
T. Piao ◽  
D. Jiang ◽  
Y. Su ◽  
...  
Keyword(s):  
Mobile Phone ◽  
Radio Astronomy ◽  
Power Supply ◽  
Earthquake Activity ◽  
Radio Interference ◽  
Worst Case ◽  
Radar Systems ◽  
Astronomical Research ◽  
Interference Problems

We first very briefly introduce the major radio facilities for astronomical research in China, and then report on the present interference situation at major radio observatories. Some of the radio interference problems are caused by paging services, mobile phone satellites, telemetry services for power supply, waterpower and earthquake activity, or radar systems, but some causes are unknown. In the worst case, harmful to radio astronomy, the Sesan VLBI station has not been able to do any observations at 92 cm due to serious radio interference problems since 1992. Still more serious interference coming from satellites can be expected in the next decade. International efforts on frequency protection should be urgently pursued if ground-based radio astronomy is to survive.

scholarly journals Computationally Efficient Compressed Sensing-Based Method via FG Nyström in Bistatic MIMO Radar with Array Gain-Phase Error Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jurong Hu ◽  
Evans Baidoo ◽  
Lei Zhan ◽  
Ying Tian
Keyword(s):  
Matching Pursuit ◽  
Phase Error ◽  
Mimo Radar ◽  
Descent Method ◽  
Gradient Descent Method ◽  
Computationally Efficient ◽  
Angle Estimation ◽  
Bistatic Mimo Radar ◽  
Phase Errors ◽  
Sparse Signal Representation

In this paper, a robust angle estimator for uncorrelated targets that employs a compressed sense (CS) scheme following a fast greedy (FG) computation is proposed to achieve improved computational efficiency and performance for the bistatic MIMO radar with unknown gain-phase errors. The algorithm initially avoids the wholly computation of the received signal by compiling a lower approximation through a greedy Nyström approach. Then, the approximated signal is transformed into a sparse signal representation where the sparsity of the target is exploited in the spatial domain. Finally, a CS method, Simultaneous Orthogonal Matching Pursuit with an inherent gradient descent method, is utilized to reconstruct the signal and estimate the angles and the unknown gain-phase errors. The proposed algorithm, aside achieving closed-form resolution for automatically paired angle estimation, offers attractive computational competitiveness, specifically in large array scenarios. Additionally, the analyses of the computational complexity and the Cramér–Rao bounds for angle estimation are derived theoretically. Numerical experiments demonstrate the improvement and effectiveness of the proposed method against existing methods.

scholarly journals Sparsity-Based DOA Estimation with Gain and Phase Error Calibration of Generalized Nested Array

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Ziang Feng ◽  
Guoping Hu ◽  
Hao Zhou
Keyword(s):  
Degrees Of Freedom ◽  
Phase Error ◽  
Doa Estimation ◽  
Model Errors ◽  
Multiple Sources ◽  
Sparse Arrays ◽  
Estimation Algorithms ◽  
Phase Errors ◽  
Representation Method ◽  
Cramer Rao Bound

Sparse arrays, which can localize multiple sources with less physical sensors, have attracted more attention since they were proposed. However, for optimal performance of sparse arrays, it is usually assumed that the circumstances are ideal. But in practice, the performance of sparse arrays will suffer from the model errors like mutual coupling, gain and phase error, and sensor’s location error, which causes severe performance degradation or even failure of the direction of arrival (DOA) estimation algorithms. In this study, we follow with interest and propose a covariance-based sparse representation method in the presence of gain and phase errors, where a generalized nested array is employed. The proposed strategy not only enhances the degrees of freedom (DOFs) to deal with more sources but also obtains more accurate DOA estimations despite gain and phase errors. The Cramer–Rao bound (CRB) derivation is analyzed to demonstrate the robustness of the method. Finally, numerical examples illustrate the effectiveness of the proposed method from DOA estimation.

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