Performance of a Low Bias DF Estimator in Wide Band Coherent Sources Environment (original) (raw)

A Super Resolution and Highly Stable Technique for Direction of Arrival Estimation of Coherent Sources for MM-Wave Radars

Progress In Electromagnetics Research B, 2020

In this paper, a new super-resolution and highly stable DOA estimation technique of coherent sources is introduced. Furthermore, the proposed technique is applied to the data collected from the AWR1243 mm-wave 76–81 GHz frequency modulated continuous wave (FMCW) radar to estimate the DOAs of real targets. A virtual antenna array is proposed to increase the array aperture size and the dimension of the data covariance matrix which effectively helps in de-correlating the received signals and in increasing the number of detectable sources and hence improving the detection resolution. Moreover, a significant improvement in the DOA estimation capability is achieved by handling the frequency domain of the received signals instead of their time-domain representations. That is because the signal to noise ratio (SNR) is increased by a multiplication factor when it is transformed using FFT which acts as a filter for the noise. The simulation results proved the superiority of the proposed techn...

DIRECTION OF ARRIVAL ESTIMATION OF WIDEBAND RF SOURCES

MSc Thesis, 2018

DOA estimation methods seem to be very useful in the reconstruction of the original received signals and help on the estimation of its location which is highly applicable in radars, sonars, seismic exploration, and military surveillance. DOA estimation methods try to figure out the parameters hidden in the sensors data using different mathematical techniques and physical properties of the geometry of the array of antennas and the impinging signals themselves. In this thesis, the DOA estimation methodology of wideband signals is studied and its computational cost and execution time are investigated. Further, recent well-known wideband algorithms are also investigated and simulated. Finally, The simulation results show the main factors that affect the computational costs of DOA methods and how to control it to reduce the complexity of the algorithms while maintaining a high resolution.

On maximum-likelihood localization of coherent signals

IEEE Transactions on Signal Processing, 1996

A hskact-We consider the problem of localizing multiple signal sources in the special case where all the signals are known a priori to be coherent. A maximum-likelihood estimator (MLE) is constructed for this special case, and its asymptotical performance is analyzed via the Cramer-Rao hound (CRB). It is proved that the CRH for this case is identical to the CRB for the case that no prior knowledge on coherency is exploited, thus establishing a quite surprising result that, asymptotically, the localization errors are not reduced by exploiting this prior knowledge. Also, we prove that in the coherent case the deterministic signals model and the stochastic signals model yield MLE's that are asymptotically identical. Simulation results confirming these theoretical results are included.

Low-Complexity Aggregation Techniques for DOA Estimation over Wide-RF Bandwidths

Electronics, 2021

Accurate direction of arrival (DOA) estimation of wideband, low-power nonstationary signals is important in many radio frequency (RF) applications. This article analyses the performance of two incoherent aggregation techniques for the DOA estimation of high chirp-rate linear frequency modulated (LFM) signals used in modern radar and electronic warfare (EW) applications. The aim is to determine suitable aggregation techniques for blind DOA estimation for real-time implementation with a frequency channelised signal. The first technique calculates a single pseudospectrum by directly combining the spatial covariance matrices from each of the frequency bins. The second technique first calculates the spatial pseudospectra from the spatial covariance matrix (SCM) from each frequency bin and then combines the spatial pseudospectra into one single estimate. Firstly, for single and multiple signal emitters, we compare the DOA estimation performance of incoherent SCM-based aggregation with tha...

Bearing detection of noised wideband sources for geolocation

18th Mediterranean Conference on Control and Automation, MED'10, 2010

In this paper, we propose a method for the localisation of wideband sources in order to locate mobile station. Indeed, directions-of-arrival of wideband sources are estimated by coherent subspace methods, which use the focusing operators, in the presence of a correlated noise and, then, the angulation is used to determine the mobile's position. Practical methods of the estimation of the coherent signal subspace are given and are compared for mobile system location.

Efficient Coherent Direction-of-Arrival Estimation and Realization Using Digital Signal Processor

IEEE Transactions on Antennas and Propagation, 2020

A novel efficient coherent direction-of-arrival (DOA) estimation method is devised in this article. First, a new cost function without the knowledge of source number is developed exploiting the Toeplitz matrices' joint diagonalization structure. Then, the revised steering vectors are used in the place of projection weights of the steering vectors to reconstruct the power spectrum in both noise and signal subspaces. The coherent DOAs are estimated using the 1-D search. Furthermore, the computational complexity of the proposed method is significantly reduced using the Nystrom approximation. Finally, the developed theoretical model is implemented on the TMS320C6678 digital signal processor (DSP) to exemplify the efficacy of the novel method.

An Overview of Different Wideband Direction of Arrival(DOA) Estimation methods

The Direction of Arrival (DOA) estimation methods are useful in Sonar, Radar and Advanced Satellite and Cellular Communication systems. In this paper different Direction of Arrival(DOA) methods such as Coherent Signal Subspace Processing (CSSM), the Weighted Average of Signal Subspaces (WAVES) and Test of Orthogonality of Projected Subspaces (TOPS) and Incoherent MUSIC(IMUSIC) is presented and their performance is also compared . The TOPS method performs better than others in mid signal-to-noise ratio (SNR) ranges, while CSSM and WAVES work better in low SNR. Incoherent methods like IMUSIC works best at high SNR.

Adaptive sparse representation for source localization with gain/phase errors

Sparse representation (SR) algorithms can be implemented for high-resolution direction of arrival (DOA) estimation. Additionally, SR can effectively separate the coherent signal sources because the spectrum estimation is based on the optimization technique, such as the 1 L norm minimization, but not on subspace orthogonality. However, in the actual source localization scenario, an unknown gain/phase error between the array sensors is inevitable. Due to this nonideal factor, the predefined overcomplete basis mismatches the actual array manifold so that the estimation performance is degraded in SR. In this paper, an adaptive SR algorithm is proposed to improve the robustness with respect to the gain/phase error, where the overcomplete basis is dynamically adjusted using multiple snapshots and the sparse solution is adaptively acquired to match with the actual scenario. The simulation results demonstrate the estimation robustness to the gain/phase error using the proposed method.