In Coherent Scenes an Uncorrelated Noise Filtering Method for DOA Estimation at Low SNR

2012 ◽  
Vol 546-547 ◽  
pp. 862-867
Author(s):  
Chang He Yu ◽  
Jian Li Li
Keyword(s):  
Signal Processing ◽  
Signal To Noise Ratio ◽  
Doa Estimation ◽  
Noise Power ◽  
Noise Filtering ◽  
Signal Processing Algorithm ◽  
Uncorrelated Noise ◽  
Filtering Method ◽  
Low Snr ◽  
Actual Signal

As we all know, noise always exists in any actual signal processing systems; its strength largely determines the working performance of one signal processing algorithm. Once the noise power is higher, many classical algorithms will lose the ability of the solution. In this paper, we propose a novel robust uncorrelated noise filtering method for direction of arrival (doa) estimation at low signal-to-noise ratio (snr) in coherent environment. Under the assumption of uncorrelated noise the proposed method can remove the uncorrelated noise variances from an array covariance matrix effectively. The characteristics of signal coherency structures and the simulation results using the novel method are presented.

scholarly journals Performance enhancement of MPM using SNR boosting techniques

2016 ◽  
Vol 5 (4) ◽  
pp. 115
Author(s):  
Shimaa Mamdouh ◽  
Amr Hussein ◽  
Hamdy Elmekaty
Keyword(s):  
Signal Processing ◽  
Performance Enhancement ◽  
Mimo Systems ◽  
Signal To Noise Ratio ◽  
Matrix Pencil ◽  
Doa Estimation ◽  
Least Square ◽  
Test Case ◽  
Recursive Least Square ◽  
Low Snr

Signal to noise ratio (SNR) boosting is one of the most important research areas in signal processing. The effectiveness of SNR boosting is not limited to a specific application rather, it is widely used in image processing, signal processing, cognitive radio, MIMO systems, digital beam forming, and direction of arrival (DOA) estimation …etc. In this paper, the recursive least square (RLS) and wavelet based de-noising filters are exploited for SNR boosting in DOA estimation techniques for further performance enhancement. The matrix pencil method (MPM) as an effortlessness and high resolution DOA estimation technique is taken as a test case. That is because it suffers from performance deterioration under low SNR regimes. The simulation results reveal that the MPM based RLS de-noising filter outperforms the MPM based wavelet de-noising filter and the traditional MPM in terms of mean square error (MSE) especially at low SNR regimes.

scholarly journals Optimization Algorithm for DOA Estimation of a Shallow Sea Target Based on Active Time Reversal

2018 ◽  
Vol 36 (2) ◽  
pp. 270-275
Author(s):  
Haixia Jing ◽  
Haiyan Wang ◽  
Zhengguo Liu ◽  
Xiaohong Shen ◽  
Zhichen Zhang
Keyword(s):  
Time Reversal ◽  
Array Signal Processing ◽  
Signal To Noise Ratio ◽  
Doa Estimation ◽  
Shallow Sea ◽  
Estimation Model ◽  
Signal To Noise ◽  
Active Time ◽  
Low Snr ◽  
Processing Theory

Time reversal technique is applied to the DOA estimation of a shallow sea target, and a method based on active time reversal (ATR) is proposed to achieve correct estimation under multipath and low signal-to-noise (SNR) conditions. Combining the classical ray theory with array signal processing theory, the conventional multipath DOA estimation model based on uniform line array and the ATR-based DOA estimation model are set up respectively. The Capon algorithm is employed to simulate the models and compare it with conventional one. The simulation results show that the ATR-based estimation model can better estimate the azimuth angle of the target than the conventional counterpart, provide higher resolution and better suppress side lobes with the same signal-to-noise ratio (SNR), especially the low SNR.

scholarly journals An OPMA for Robust Mutual Coupling Coefficients Estimation of URA with Single Snapshot in MIMO HF Sky-Wave Radar

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Yuguan Hou ◽  
Qingguo Jin ◽  
Shaochuan Wu ◽  
Zhuoming Li
Keyword(s):  
Mutual Coupling ◽  
Signal To Noise Ratio ◽  
Mean Shift ◽  
Success Probability ◽  
Doa Estimation ◽  
Coupling Coefficients ◽  
Music Algorithm ◽  
Low Snr ◽  
Wave Radar ◽  
Single Snapshot

Due to the fluctuation of the signal-to-noise ratio (SNR) and the single snapshot case in the MIMO HF sky-wave radar system, the accuracy of the online estimation of the mutual coupling coefficients matrix of the uniform rectangle array (URA) might be degraded by the classical approach, especially in the case of low SNR. In this paper, an Online Particle Mean-Shift Approach (OPMA) is proposed, which is to get a relatively more effective estimation of the mutual coupling coefficients matrix with the low SNR. Firstly, the spatial smoothing technique combined with the MUSIC algorithm of URA is introduced for the DOA estimation of the multiple targets in the case of single snapshot which are taken as coherent sources. Then, based on the idea of the particle filter, the online particles with a moderate computational complexity are used to generate some different estimation results. Finally, the mean-shift algorithm is applied to get a more robust estimate of the equivalent mutual coupling coefficients matrix. The simulation results demonstrate the validity of the proposed approach in terms of the success probability, the statistics of bias, and the variance. The proposed approach is more robust and more accurate than the other two approaches.

Improved TOPS about Direction of Arrival Estimation for Wideband Signals

2011 ◽  
Vol 105-107 ◽  
pp. 2051-2054
Author(s):  
Bin He
Keyword(s):  
Signal To Noise Ratio ◽  
Full Rank ◽  
Poor Performance ◽  
Direction Of Arrival ◽  
Doa Estimation ◽  
Signal Subspace ◽  
Low Snr ◽  
Wideband Signals ◽  
Array Aperture ◽  
Array Output

The study about the direction-of-arrival (DOA) estimation for wideband signals is a basic topic of Signal Processing. The method called test of orthogonality of projected subspaces (TOPS) does not require initial values to form focusing matrix compared with the coherent signal subspace method (CSSM), but it has poor performance for coherent wideband signals at low signal-to-noise ratio (SNR). Based on the lack of the conventional TOPS, this paper reconstructs a set of new matrices with the narrowband correlated matrices coming from the DFT decomposition of the array output and modifies the method frame of the conventional TOPS. So we get a set of reconstructed matrices with full rank corresponding to each frequency bin, and which have no array aperture loss. The improved TOPS can estimate the DOA for coherent wideband sources at low SNR, and enhances the performance of the conventional TOPS. Simulation results show that the improved TOPS is effective, and the total performance of which is similar to the rotational signal-subspace (RSS) method.

The Technology of Line-Spectrum Enhancement Based on Image Processing

2012 ◽  
Vol 429 ◽  
pp. 308-312
Author(s):  
Dai Zhu Zhu ◽  
Wen Hua Huang
Keyword(s):  
Image Processing ◽  
Signal Processing ◽  
Data Analysis ◽  
Frequency Domain ◽  
Signal To Noise Ratio ◽  
Trial Data ◽  
Line Spectrum ◽  
Signal To Noise ◽  
Time Frequency ◽  
Low Snr

Time-frequency spectrogram analysis is a basic method in passive radar and sonar. It′s necessary to enhance the line-spectrum to improve the performance in low SNR(Signal to Noise Ratio) and strong interference presented that wider detecting range and long reacting time can be obtained. The traditional line-spectrum enhancing technology based on signal′s coherence can′t work well in very low SNR, and the performance will drop sharply when the line-spectrums are close in frequencies or the number of line-spectrums increases. A new method which combines image processing with signal processing is brought out to overcome these defects. It can work well when the SNR in frequency domain is close to 0dB,which is much lower than ALE and other traditional technology. The results derived from simulation and trial data analysis show that it′s stable and can be applied in the field with line-spectrums.

scholarly journals A Signal Processing Algorithm of Two-Phase Staggered PRI and Slow Time Signal Integration for MTI Triangular FMCW Multi-Target Tracking Radars

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2296
Author(s):  
Taiwen Tang ◽  
Chen Wu ◽  
Janaka Elangage
Keyword(s):  
Signal Processing ◽  
Signal To Noise Ratio ◽  
Time Signal ◽  
Fast Fourier Transformation ◽  
Signal Integration ◽  
Target Movement ◽  
Two Phase ◽  
Signal Processing Algorithm ◽  
Fmcw Radar ◽  
Multi Target Tracking

In this paper, a novel signal processing algorithm for mitigating the radar blind speed problem of moving target indication (MTI) for frequency modulated continuous wave (FMCW) multi-target tracking radars is proposed. A two-phase staggered pulse repetition interval (PRI) solution is introduced to the FMCW radar system. It is implemented as a time-varying MTI filter using twice the hardware resources as compared to a uniform PRI MTI filter. The two-phase staggered PRI FMCW waveform is still periodic with a little more than twice the period of the uniform PRI radar. We also propose a slow time signal integration scheme for the radar detector using the post-fast Fourier transformation Doppler tracking loop. This scheme introduces 4.77 dB of extra signal processing gain to the signal before the radar detector compared with the original uniform PRI FMCW radar. The validation of the algorithm is done on the field programmable logic array in the loop test bed, which accurately models and emulates the target movement, line of sight propagation and radar signal processing. A simulation run of tracking 16 s of the target movement near or at the radar blind speed shows that the total degradation from the raw post-fast Fourier transformation received signal to noise ratio is about 2 dB. With a 20 dB post-processing signal to noise ratio of the proposed algorithm for the moving target at around a 20 km range and with about a −3.5 dB m2 radar cross section at a 1.5 GHz carrier frequency, the tracking errors of the two-dimensional angles with a 4×4 digital phased array are less than 0.2 degree. The range tracking error is about 28 m.

Sign in / Sign up

Export Citation Format

Share Document