Research On Direction Of Arrival Algorithm For Distributed Array

Direction of Arrival estimation is one of the important topics in array signal processing,which is often used to localize and track the target with high-precision.It is widely used in many scenarios,such as radar detection,wireless communication and so on.Compared with traditional antenna array,distributed antenna array is capable of expanding the array aperture to achieve higher angular resolution without increasing hardware cost.Moreover,the distributed antenna array is able to improve its mobility through the rapid movement and flexible deployment of sub-arrays.Therefore,the distributed antenna array has attracted extensive attention.However,as the scale of distributed arrays increases,the hardware costs,power consumption,and the cost of the data storage will be significantly increased with the use of high-precision.In addition,the data collected by each sub-array need to be transmitted to the central processing unit,since each sub-array in the distributed array works independently.At this point,we need to consider the massive data wireless transmission under large-scale arrays.Aiming at these problems,several DOA estimation algorithms for distributed array with low-precision quantization and mixed-precision quantization is proposed.The contributions are summarized as follows:(1)The mathematical expressions of the covariance matrix for distributed array under low-precision quantization and mixed-precision quantization respectively is derived,so as to analyze the effect caused by quantization noise,since the eigen sub-space algorithms perform DOA estimation based on the covariance matrix of received signal.(2)The Cramer-Rao Lower Bound of the distributed arrays with 1-bit ADC is proposed in order to evaluate the performance of the DOA estimation algorithm for distributed array with 1-bit quantization.(3)Aiming at the problems of the high hardware costs,power consumption,and massive data transmission caused by large-scale distributed arrays with high-precision ADC,a DOA estimation algorithm for distributed array with low-precision quantization is proposed.The proposed algorithm not only reduces the hardware cost and power consumption,but also reduces the burden of data storage and transmission for each subarray.The numerical results manifest that the performance of the 1-bit Dual Resolution-ESPRIT algorithm is close to the Cramer-Rao Lower Bound under 1-bit ADC distributed array when the signal-to-noise ratio is higher than the SNR threshold.Compared with the 1-bit ESPRIT algorithm under the uniform linear array,the root mean square error of the 1-bit Dual Resolution-ESPRIT algorithm is reduced by about 82.6% when the baseline length is 20λ.(4)Aiming at the problem of performance loss of the DOA estimation algorithm for distributed array with low-precision quantization,the MP-Dual Resolution-ESPRIT algorithm for distributed array with mixed-precision quantization is proposed.The proposed algorithm is able to perform DOA estimation based on the received signal data quantified by high-precision and low-precision ADC,which can not only make up for the performance loss under low precision quantization,but also reduce the hardware cost and power consumption to a certain extent compared with the full high precision ADC.The numerical results manifest that the root mean square error of the MP-Dual Resolution-ESPRIT algorithm is reduced by about 25.9% compared with the 1-bit Dual Resolution-ESPRIT algorithm.