In this paper, we investigate joint estimation of direction-of-departure (DOD) and direction-of-arrival (DOA) of multiple targets in bistatic MIMO radar exploiting nested arrays. By configuring 2-level nested arrays i...
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ISBN:
(纸本)9781785616723
In this paper, we investigate joint estimation of direction-of-departure (DOD) and direction-of-arrival (DOA) of multiple targets in bistatic MIMO radar exploiting nested arrays. By configuring 2-level nested arrays in the transmit and receive arrays, a large number of virtual array apertures are introduced. Therefore, the spatial resolution of the MIMO radar system is significantly enhanced. Moreover, the maximum number of the identifiable targets is enlarged to a higher degree compared with traditional uniform linear arrays. The signal model is formulated by the exploitation of the nested arrays. A novel row extraction method is proposed to construct an observed data vector for joint angle estimation. The simulation results validate the theoretical algorithm.
The coarray techniques, e.g., nested and coprime arrays, can significantly improve degrees of freedom (DOFs) via constructing a so-called difference coarray, which enables underdetermined direction-of-arrival (DOA) es...
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The coarray techniques, e.g., nested and coprime arrays, can significantly improve degrees of freedom (DOFs) via constructing a so-called difference coarray, which enables underdetermined direction-of-arrival (DOA) estimation within reach in the presence of unknown nonuniform noise. There are repeated lags in the difference coarray, which also contain useful statistical information. In this paper, the repeated lags are properly used for DOA estimation algorithm design in unknown nonuniform noise environments. Specifically, the number of repeated lags in the difference coarray is rigorously given. Then these repeated lags and unique lags are judiciously rearranged to form a pseudo data set, which is composed of linearly independent vectors. Based on the pseudo data set, we propose two algorithms for DOA estimation in the presence of unknown nonuniform noise. One is a searching algorithm without source number knowledge (SASNK), and the other is a multi-snapshot compressive sensing method (MSCS) with better DOA estimation performance. The MSCS also does not require source number information. Numerical results are included to showcase the effectiveness of the proposed algorithms.
The optimum placement of receiving telescope antennas is a central topic for designing radio interferometric arrays, and this determines the performance of the obtained information. A variety of arrays are designed fo...
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The optimum placement of receiving telescope antennas is a central topic for designing radio interferometric arrays, and this determines the performance of the obtained information. A variety of arrays are designed for different purposes, and they perform poorly in scalability. In this paper, we consider a subclass of structured sparse arrays, namely nested arrays, and examine the important role of "coarray" in interferometric synthesis imaging, which is utilized to design nested array configurations for a complete uniform Fourier plane coverage in both supersynthesis and instantaneous modes. Both nested arrays and the theory of the coarray have rich research achievements, and we apply them to astronomy to design arrays with good scalability and imaging performance. Simulated celestial source image retrieval performance validates the effectiveness of nested interferometric arrays.
Direction finding is a hot research area in radar and sonar systems. In the case of q 2, the 2qth-order cumulant based direction of arrival (DOA) estimation algorithm for the 2q-level nested array can achieve high res...
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Direction finding is a hot research area in radar and sonar systems. In the case of q 2, the 2qth-order cumulant based direction of arrival (DOA) estimation algorithm for the 2q-level nested array can achieve high resolution performance. A virtual 2qth-order difference co-array, which contains O(N-2q) virtual sensors in the form of a uniform linear array (ULA), is yielded and the Gaussian noise is eliminated. However, some virtual elements are separated by the holes among the 2qth-order difference co-array and cannot be fully used. Even though the application of the multi-frequency method for minimum frequency separation (MFMFS) can fill the holes with low computation complexity, it requires that the number of frequencies must increase with the number of holes. In addition, the signal spectra have to be proportional for all frequencies, which is hard to satisfy when the number of holes is large. Aiming at this, we further propose a multi-frequency method for a minimum number of frequencies (MFMNF) and discuss the best frequency choice under two specific situations. Simulation results verify that, compared with the MFMFS method, the proposed MFMNF method can use only one frequency to fill all the holes while achieving a longer virtual array and the DOA estimation performance is, therefore, improved.
We investigate the problem of direction of arrival (DOA) estimation using sparse linear arrays, such as co-prime and nested arrays, in the case of missing data resulting from sensor failures. We introduce a signal mod...
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ISBN:
(纸本)9781509041183
We investigate the problem of direction of arrival (DOA) estimation using sparse linear arrays, such as co-prime and nested arrays, in the case of missing data resulting from sensor failures. We introduce a signal model where sensor failures occur after taking certain number of snapshots. We formulate a structured covariance estimation problem by exploiting the special geometry of sparse linear arrays, which also provides enhanced degrees of freedom. Numerical examples show that, by utilizing the information in both complete measurements and incomplete measurements, our method achieves better estimation accuracy than the traditional method using only complete measurements.
nested array-A new type of two dimensional arrays with sensors (antennas) on lattice was proposed these years. This paper designs a novel antenna placement scheme at base station based on 2-D nested array. We utilize ...
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ISBN:
(纸本)9781467399562
nested array-A new type of two dimensional arrays with sensors (antennas) on lattice was proposed these years. This paper designs a novel antenna placement scheme at base station based on 2-D nested array. We utilize the difference co-array, which is an important characteristic of nested array, to model and generate all antennas (virtual antennas) in the covariance matrix of channel (virtual channel) coefficients. Based on this fact and inferences, we also model a Massive MIMO antenna system with nested configuration and list all mathematics procedures to calculate its performance with achievable rate. A zero forcing detector is applied to this Massive MIMO system and the spectral efficiency is given at the end. The numeric result proves our mathematics derivation and also the feasibility in real world. What's more, given the same number of antennas, the proposed method could achieve higher sum-rate capacity and better spectral efficiency.
This paper introduces a new array geometry called Fractal based Sub array (FBSA) for DOA estimation. The FBSA consists of two Sub-arrays, the MRA and the Fractal array (FA). A recursive use of Cantor set generates the...
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ISBN:
(纸本)9781728118826
This paper introduces a new array geometry called Fractal based Sub array (FBSA) for DOA estimation. The FBSA consists of two Sub-arrays, the MRA and the Fractal array (FA). A recursive use of Cantor set generates the FA. The Difference Co-array of FBSA is a hole-free array. The numerical simulation demonstrates that the proposed array, with reduced mutual coupling, has good performance compared to nested array.
This work presents a new array geometry, which is capable of providing O(M~2N~2) degrees of freedom (DOF) using only MN physical sensors via utilizing the second-order statistics of the received data. This new array i...
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ISBN:
(纸本)9781479999897
This work presents a new array geometry, which is capable of providing O(M~2N~2) degrees of freedom (DOF) using only MN physical sensors via utilizing the second-order statistics of the received data. This new array is composed of multiple, identical minimum redundancy subarrays, whose positions follow a minimum redundancy configuration. Thus the new array is a minimum redundancy array (MRA) of MRA subarrays, and is termed as nested MRA. The sensor positions, aperture length, and the number of DOF of the new array can be predicted if these parameters of MRA subarrays are given. Numerical simulations demonstrate the superiorities of the proposed array geometry in resolving more sources than sensors and DOA estimation.
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