scholarly journals DOA Estimation Performance Analysis and Verification of Dual Crossed-Loop/Monopole Antenna Array

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Sijie Wang ◽  
Biyang Wen ◽  
Yingwei Tian
Keyword(s):  
Antenna Array ◽  
Estimation Error ◽  
Doa Estimation ◽  
Hf Radar ◽  
Estimation Accuracy ◽  
Dominant Factor ◽  
Application Range ◽  
Estimation Performance ◽  
Wave Radar ◽  
Target Monitoring

The compact high-frequency surface wave radar using a crossed-loop/monopole (CLM) antenna as the receiving sensor has been widely used in ocean remote sensing and target monitoring. However, the direction of arrival (DOA) estimation accuracy of a single CLM antenna is the dominant factor that restricts the target monitoring performance of the compact HF radar. Besides, the single CLM antenna can estimate two signals simultaneously at most, but its effectiveness is challenged by the pattern distortion and the existence of coherent sources, which limits the application range of the compact HF radar. In this study, a compact array combining two CLM antennas is proposed to improve the DOA estimation accuracy and solve the multisource DOA estimation problem. The estimation error and multisource DOA estimation performance of a dual CLM antenna array are analyzed by formula derivation and simulation. Furthermore, the field experiment results are given to demonstrate the performance improvement of the dual CLM antenna array.

scholarly journals An Effective Technique for Enhancing Direction Finding Performance of Virtual Arrays

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Wenxing Li ◽  
Xiaojun Mao ◽  
Wenhua Yu ◽  
Chongyi Yue
Keyword(s):  
Antenna Array ◽  
Interpolation Method ◽  
Doa Estimation ◽  
Direction Finding ◽  
Estimation Accuracy ◽  
Signal Subspace ◽  
Effective Technique ◽  
Resolution Capability ◽  
Significant Bias ◽  
Virtual Array

The array interpolation technology that is used to establish a virtual array from a real antenna array is widely used in direction finding. The traditional interpolation transformation technology causes significant bias in the directional-of-arrival (DOA) estimation due to its transform errors. In this paper, we proposed a modified interpolation method that significantly reduces bias in the DOA estimation of a virtual antenna array and improves the resolution capability. Using the projection concept, this paper projects the transformation matrix into the real array data covariance matrix; the operation not only enhances the signal subspace but also improves the orthogonality between the signal and noise subspace. Numerical results demonstrate the effectiveness of the proposed method. The proposed method can achieve better DOA estimation accuracy of virtual arrays and has a high resolution performance compared to the traditional interpolation method.

scholarly journals Emitter Velocity Estimation Comparison for Frequency Difference of Arrival Measurement Based Single and Multiple Reference Lateration Algorithm

2018 ◽  
Vol 17 (1) ◽  
pp. 9-15
Author(s):  
Abdulmalik Shehu Yaro ◽  
Ahmad Zuri Sha'ameri
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Equilateral Triangle ◽  
Estimation Error ◽  
Velocity Estimation ◽  
Instantaneous Velocity ◽  
Frequency Difference ◽  
Estimation Accuracy ◽  
Estimation Performance ◽  
Multiple Reference

The accuracy at which the instantaneous velocity and position of a non-stationary emitting source estimated using a lateration algorithm depends on several factors such as the lateration algorithm approach, the number and choice of reference receiving station (RS) used in developing the lateration algorithm. In this paper, the use of multiple reference RSs was proposed to improve the velocity estimation accuracy of the frequency difference of arrival (FDOA) based lateration algorithm. The velocity estimation performance of the proposed multiple reference FDOA based lateration algorithm is compared with the conventional approach of using single reference RS at some selected emitter positions using Monte Carlo simulation. Simulation result based on an equilateral triangle RS configuration shows that the use of multiple reference RSs improved the velocity estimation accuracy of the lateration algorithm. Based on the selected emitter positions, a reduction in velocity estimation error of about 0.033  and 1.31  for emitter positions at ranges 0.5 km and 5 km respectively was achieved using the multiple reference lateration algorithm.

scholarly journals Validation and Evaluation of a Ship Echo-Based Array Phase Manifold Calibration Method for HF Surface Wave Radar DOA Estimation and Current Measurement

2020 ◽  
Vol 12 (17) ◽  
pp. 2761
Author(s):  
Chen Zhao ◽  
Zezong Chen ◽  
Jian Li ◽  
Fan Ding ◽  
Weimin Huang ◽  
...  
Keyword(s):  
Phased Array ◽  
Phase Error ◽  
Doa Estimation ◽  
Calibration Method ◽  
Current Measurement ◽  
Hf Radar ◽  
Identification System ◽  
Error Matrix ◽  
Wave Radar ◽  
Array Calibration

Shore-based phased-array HF radars have been widely used for remotely sensing ocean surface current, wave, and wind around the world. However, phase uncertainties, especially phase distortions, in receiving elements significantly degrade the performance of beam forming and direction-of-arrival (DOA) estimation for phased-array HF radar. To address this problem, the conventional array signal model is modified by adding a direction-based phase error matrix. Subsequently, an array phase manifold calibration method using antenna responses of incoming ship echoes is proposed. Later, an assessment on the proposed array calibration method is made based on the DOA estimations and current measurements that are obtained from the datasets that were collected with a multi-frequency HF (MHF) radar. MHF radar-estimated DOAs using three calibration strategies are compared with the ship directions that are provided by an Automatic Identification System (AIS). Additionally, comparisons between the MHF radar-derived currents while using three calibration strategies and Acoustic Doppler Current Profilers (ADCP)-measured currents are made. The results indicate that the proposed array calibration method is effective in DOA estimation and current measurement for phased-array HF radars, especially in the phase distortion situation.

scholarly journals Spatial Differencing Reconstruction Based Low-Angle DOA Estimation with MIMO Radar

2018 ◽  
Vol 36 (1) ◽  
pp. 182-188
Author(s):  
Qin Zhang ◽  
Linrang Zhang ◽  
Junpeng Shi ◽  
Yannian Zhou ◽  
Yaning Liu
Keyword(s):  
Multiple Input Multiple Output ◽  
Estimation Algorithm ◽  
Doa Estimation ◽  
Spatial Diversity ◽  
Mimo Radar ◽  
Estimation Accuracy ◽  
Signal Model ◽  
Estimation Performance ◽  
Multiple Input ◽  
Input Multiple Output

Due to the multipath effect, the direction of arrival (DOA) estimation performance for low-angle targets decreases greatly. To overcome this problem, this paper proposes a spatial differencing reconstruction based DOA estimation algorithm by using the received signal model of multiple input multiple output (MIMO) radar. Combining with the spatial diversity of MIMO radar, the proposed method can first use the multipath echo power to select the best signal. Then, a spatial differencing based iterative scheme is developed to reduce the effect of additive noise, resulting in a better estimation performance for low-angle targets. Simulation results show that the proposed method has better advantages in suppressing noise and improving estimation accuracy.

The Large Millimeter Wave Radar Phased Antenna Array

2000 ◽  
Vol 54 (10) ◽  
pp. 101-111
Author(s):  
Aleksey Alekseevich Tolkachev ◽  
Vasiliy Andreevich Makota ◽  
Mariya Petrovna Pavlova ◽  
Anatoliy Moiseevich Nikolaev ◽  
Vladimir Victorovich Denisenko ◽  
...  
Keyword(s):  
Antenna Array ◽  
Millimeter Wave ◽  
Millimeter Wave Radar ◽  
Wave Radar ◽  
Phased Antenna Array

scholarly journals Optimal Tuner Selection for Kalman Filter-Based Aircraft Engine Performance Estimation

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Donald L. Simon ◽  
Sanjay Garg
Keyword(s):  
Kalman Filter ◽  
Estimation Error ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Experimental Simulation ◽  
Tuning Parameter ◽  
Estimation Accuracy ◽  
On Line

A linear point design methodology for minimizing the error in on-line Kalman filter-based aircraft engine performance estimation applications is presented. This technique specifically addresses the underdetermined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multivariable iterative search routine that seeks to minimize the theoretical mean-squared estimation error. This paper derives theoretical Kalman filter estimation error bias and variance values at steady-state operating conditions, and presents the tuner selection routine applied to minimize these values. Results from the application of the technique to an aircraft engine simulation are presented and compared with the conventional approach of tuner selection. Experimental simulation results are found to be in agreement with theoretical predictions. The new methodology is shown to yield a significant improvement in on-line engine performance estimation accuracy.

Assessment of 2D ultrasound fluid volume estimation accuracy in different shaped objects: an in vitro study

2019 ◽  
Vol 61 (2) ◽  
pp. 253-259
Author(s):  
Iroshani Kodikara ◽  
Iroshini Abeysekara ◽  
Dhanusha Gamage ◽  
Isurani Ilayperuma
Keyword(s):  
Estimation Error ◽  
In Vitro Study ◽  
High Accuracy ◽  
Volume Estimation ◽  
Estimation Accuracy ◽  
Rater Agreement ◽  
Actual Volume ◽  
2D Ultrasound ◽  
One Way Anova

Background Volume estimation of organs using two-dimensional (2D) ultrasonography is frequently warranted. Considering the influence of estimated volume on patient management, maintenance of its high accuracy is empirical. However, data are scarce regarding the accuracy of estimated volume of non-globular shaped objects of different volumes. Purpose To evaluate the volume estimation accuracy of different shaped and sized objects using high-end 2D ultrasound scanners. Material and Methods Globular (n=5); non-globular elongated (n=5), and non-globular near-spherical shaped (n=4) hollow plastic objects were scanned to estimate the volumes; actual volumes were compared with estimated volumes. T-test and one-way ANOVA were used to compare means; P<0.05 was considered significant. Results The actual volumes of the objects were in the range of 10–445 mL; estimated volumes ranged from 6.4–425 mL ( P=0.067). The estimated volume was lower than the actual volume; such volume underestimation was marked for non-globular elongated objects. Regardless of the scanner, the highest volume estimation error was for non-globular elongated objects (<40%) followed by non-globular near-spherical shaped objects (<23.88%); the lowest was for globular objects (<3.6%). Irrespective of the shape or the volume of the object, volume estimation difference among the scanners was not significant: globular (F=0.430, P=0.66); non-globular elongated (F=3.69, P=0.064); and non-globular near-spherical (F=4.00, P=0.06). A good inter-rater agreement (R=0.99, P<0.001) and a good correlation between actual versus estimated volumes (R=0.98, P<0.001) were noted. Conclusion The 2D ultrasonography can be recommended for volume estimation purposes of different shaped and different sized objects, regardless the type of the high-end scanner used.

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