CN103780296B - A kind of signal of Homogeneous Circular array antenna receives and distortion antidote - Google Patents

Abstract

The invention relates to a signal receiving and distortion correction method of a uniform circular array antenna, comprising the following steps: step 1: estimation of the amplitude/phase gain matrix of the receiving link antenna array; step 2: mutual coupling coefficient of the receiving link antenna array Matrix estimation; Step 3: Correct the receive link according to the estimated magnitude/phase gain matrix and mutual coupling coefficient matrix of the receive link antenna array; Step 4: Estimate the gain matrix of the transmit link antenna array; Step 5: Use the estimated The gain matrix of the transmitting link and the mutual coupling coefficient matrix of the receiving link are used to perform amplitude/phase correction and mutual coupling correction on the transmitting link. Compared with the prior art, the present invention has the advantages of being able to correct the receiving and transmitting links of the uniform circular array at the system level, with complete schemes and good correction effects.

Description

A Signal Reception and Distortion Correction Method of Uniform Circular Array Antenna

technical field

The invention relates to signal reception and distortion correction technology of smart antennas in the communication field, in particular to a signal reception and distortion correction method of a uniform circular array antenna.

Background technique

With the development of wireless mobile communication technology, the demand for mobile communication is also increasing day by day. The limitations of wireless network technology make it unable to continue to meet high communication needs. When users deploy wireless local area networks, wireless signals are often interfered, signal The penetrating ability is poor, resulting in the general problem of short transmission distance. Using new technologies to improve the efficiency of the use of limited frequency resources has become a subject of increasing concern.

Beamforming is a combination of antenna technology and digital signal processing technology. It is used for directional signal transmission or reception so that the system can support more users in a limited spectrum, thereby doubling the efficiency of spectrum usage. Beamforming technology was first applied to phased array radar, which formed narrow beams for scanning through multiple antenna units, and was later applied to the communication field, mainly used in base stations in civil mobile communications. Its basic principle uses multi-antenna technology to weight and synthesize the received signals, determine the direction of signal arrival, accurately locate the signal source, generate multi-path high-gain directional spot beams, and provide excellent deep non-line-of-sight functions.

When the system uses an array antenna, the received signal is affected by the amplitude/phase error of the antenna element itself, and the distance between the elements of the antenna array is usually less than one-half of the wavelength, so that the elements of the array antenna have Strong coupling, this coupling will distort the transmission and reception of the signal, which will have a greater impact on the beamforming of the antenna array and the direction of arrival estimation, making the received signal seriously distorted and greatly affecting the beam Shaped receiver performance. Therefore, it is of great significance to obtain the mutual coupling coefficient of the antenna array through calculation or experimental measurement, and to perform software or hardware mutual coupling correction based on this. The key basis for mutual coupling correction is the mutual coupling correction coefficient matrix between array elements.

At present, some scholars at home and abroad are working on the research of array error correction methods. The proposed correction methods are mainly divided into two categories: self-correction methods and active correction methods. The active rectification method is to estimate the array error parameters off-line by setting an auxiliary signal source whose orientation is precisely known in space; while the self-rectification method gives the estimated value of the array error parameters and the source orientation at the same time. Although the self-correction method does not need to rely on the auxiliary source with a known position, and thus does not need to overcome the uncertain factors carried in the auxiliary source signal, the processing is usually very complicated, and the real-time performance of the algorithm is high. Among many active correction methods, See C M S et al. proposed an active correction for array errors such as array element mutual coupling and amplitude-phase error in the document method forarray calibration in high-resolution sensor arrayprocessing of IEE Proceedings-Radar, Sonarand Navigation. Algorithm, the algorithm obtains a set of direction vectors of the correction source through matrix eigendecomposition to estimate the array error. In order to simplify the discussion of the problem, this document also estimates the product of the mutual coupling matrix and the amplitude-phase error matrix as a whole, but the algorithm does not Taking full advantage of the influence of DOA estimation on mutual coupling coefficient estimation, the iterative process cannot separate the interweaving of DOA error and mutual coupling coefficient error, and the calculation process is still redundant.

Contents of the invention

The purpose of the present invention is to provide a signal receiving and distortion correction method of a uniform circular array antenna in order to overcome the above-mentioned defects in the prior art, which can perform system-level correction on the receiving and transmitting links of the uniform circular array. The scheme is complete and The correction effect is good.

The purpose of the present invention can be achieved through the following technical solutions:

A method for signal reception and distortion correction of a uniform circular array antenna, characterized in that it comprises the following steps:

Step 1: Estimate the magnitude/phase gain matrix of the receive link antenna array;

Step 2: Estimation of the mutual coupling coefficient matrix of the receiving link antenna array;

Step 3: Correct the receiving link according to the estimated amplitude/phase gain matrix and mutual coupling coefficient matrix of the receiving link antenna array;

Step 4: Estimation of the gain matrix of the transmit link antenna array;

Step 5: Using the estimated gain matrix of the transmitting link and the mutual coupling coefficient matrix of the receiving link, perform amplitude/phase correction and mutual coupling correction on the transmitting link.

Using near-field coupling antennas and far-field correction sources, the amplitude/phase gain matrix and mutual coupling coefficient matrix of the receiving chain antenna array are sequentially calculated.

The estimation of the mutual coupling coefficient matrix C of the receiving link antenna array is specifically:

The estimation of the mutual coupling coefficient matrix C is simplified to the estimation of the representation vector c of the mutual coupling matrix,

If n=2k+1(k=1,2,...), c={1c ₁ c ₂ ...c _k |c _k ...c ₂ c ₁ };

If n=2k (k=1,2,..), c={1c ₁ c ₂ ...c _k-1 c _k c _k-1 ...c ₂ c ₁ }.

Where c _i (i=1,2,...,k) is the coupling coefficient between two array elements whose angle difference to the center of the circle is (2π/n)i; n is the number of circular antenna array elements, and k is the corresponding The number of independent elements of .

The rectification of the receiving link is specifically as follows:

First perform amplitude/phase gain error correction, then use the DOA estimation results to estimate the mutual coupling coefficient matrix, the corrected signal Among them, Y _n×s is the actual received signal of the circular array, C _n×n is the mutual coupling coefficient matrix of the n-element circular array, and G _n×n is the gain error matrix.

, the amplitude/phase correction and mutual coupling correction of the transmission link are specifically:

Assume that the antenna array intends to transmit a signal X, and correct the amplitude, phase and mutual coupling errors before transmission. The actual transmitted signal is X'=G _t ^-1 C ^-1 X, and the signal actually radiated to the far field after correction is Y=ACG _t X'=ACG _t G _t ^-1 C ^-1 X=AX, where A is the direction vector, C is the mutual coupling coefficient matrix of the circular array, and G _t is the transmit link gain error matrix.

Compared with the prior art, the present invention provides a complete set of uniform circular antenna array transmitting link, receiving link signal distortion correction method, constitutes a loop correction system, it can not only correct the receiving link of the antenna array Distortion correction, the estimation of mutual coupling coefficient is applied to the transmission chain, and distortion correction is performed on the transmission chain, which uses less auxiliary sources and has high estimation accuracy.

Description of drawings

Fig. 1 is a schematic structural diagram of an array antenna applied in the present invention;

Fig. 2 is a working flow diagram of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

This embodiment is carried out on the premise of the technical solution of the present invention, and the detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

As shown in Figure 1, taking a uniform circular array antenna with 15 elements as an example, all the elements are half-wave antennas, operating at a frequency of 5 GHz, and the radius of the circular array is R=6λ/2π. The receiving and transmitting link distortion correction method comprises the following steps:

Step 1: Set the near-field correction signal source at the center of the uniform circular array antenna, the correction source sends the signal z _1×m = {z ₁ , z ₂ ,..., z _m }, m is the length of the correction sequence, and the antenna receive signal y _i (i=1,...15) is the received signal sequence of the i-th array element. Amplitude/phase matrix G _15×15 =diag{g}, g={1g ₂ g ₃ ...g ₁₅ }, then the amplitude/phase coefficient g _i =avg{y _i ./y is estimated by near-field correction ₁ }, i=2,3...15; use g _i to reconstruct the magnitude/phase matrix G _15×15 =diag{1g ₂ g ₃ ...g ₁₅ };

Step 2: The far-field signal source sends the signal sequence x _1×s , corrects the amplitude/phase error of the received signal, multiplies the received signal Y ₁ ′ _5×s matrix to the left by the inverse matrix of the amplitude/phase matrix, and obtains the corrected signal array

DOA algorithm is used to estimate the direction of arrival on Y _15×s , and the estimated angle information θ is obtained. According to the angle information and the topology structure of the uniform circular array, the direction vector A _15×1 (θ) is calculated.

Correlate the received signal matrix Y _15×s with the received signal of the first array element, namely Perform discrete Fourier transform on the correlation R _y and direction vector A _15×1 (θ) of the received signal respectively, and then divide the generated two frequency domain vectors to obtain the characterization vector c′ of the coupling matrix in the frequency domain

c'＝FFT[R _y ]./FFT[A _15×1 (θ)]

The coupling matrix C _15×15 is a symmetric toeplitz matrix with cyclic properties, and the diagonal elements are 1. C _15×15 can be characterized by its first row/column c,

c = {1c ₁ c ₂ ... c ₇ c ₇ ... c ₂ c ₁ };

Where c _i (i=1,2,...,7) is the coupling coefficient between two array elements whose angle difference to the center of the circle is (2π/n)i.

Perform inverse Fourier transform on the coupling coefficient frequency domain representation vector c′ to obtain c″, c″={c″ ₁ c″ ₂ ...c″ ₁₅ }, and normalize the first component of the c″ vector , get the characterization vector c of the symmetric toeplitz coupling matrix,

c"=IFFT(c')

c=c″/c″ ₁

The mutual coupling coefficient matrix C _15×15 is obtained by reconstructing with c.

Step 3: Correct the receiving link according to the amplitude/phase gain matrix and the mutual coupling coefficient matrix,

Step 4: Transmit link circular antenna array to send m groups of snapshot vectors For a specific k (k=1,2...15), the components x _i of the vector

make For m groups x ^k , find The average value of , so that the estimated value of the amplitude-phase gain matrix at the sending end can be obtained

Step 5: Correct the transmitted signal of the antenna array. Assuming that the antenna array intends to transmit a signal X, the amplitude, phase and mutual coupling errors should be corrected before transmission. The actual transmitted signal is X'=G _t ^-1 C ^-1 X, so that the actual signal radiated to the far field is Y=ACGX '=ACG _t G _t ^-1 C ^-1 X=AX.

Claims (3)

1. A signal receiving and distortion correction method of uniform circular array antenna, is characterized in that, comprises the following steps: Step 1: Estimation of the amplitude/phase gain matrix of the receive link antenna array; Step 2: Estimation of the mutual coupling coefficient matrix of the receiving link antenna array; Step 3: Perform amplitude/phase correction and mutual coupling correction on the receiving link according to the estimated amplitude/phase gain matrix and mutual coupling coefficient matrix of the receiving link antenna array; Step 4: Estimate the amplitude/phase gain matrix of the transmit link antenna array; Step 5: Using the estimated amplitude/phase gain matrix of the transmitting link antenna array and the mutual coupling coefficient matrix of the receiving link antenna array, perform amplitude/phase correction and mutual coupling correction on the transmitting link; The amplitude/phase correction and mutual coupling correction of the receiving link are specifically as follows: First, the amplitude/phase gain error correction is performed, and then the mutual coupling coefficient matrix of the receiving link antenna array is estimated by using the DOA estimation result, and the corrected signal Among them, Y _n×s is the actual received signal of the receiving link antenna array, C _n×n is the mutual coupling coefficient matrix of the n-element receiving link antenna array, and G _n×n is the gain error matrix; The amplitude/phase correction and mutual coupling correction of the transmitting link are specifically as follows: Assuming that the transmit link antenna array intends to transmit signal X, the amplitude/phase gain error correction and mutual coupling error correction are performed before transmission. The actual transmitted signal is X'=G _t ^-1 C ^-1 X, and the actual radiation reaches far after correction. The field signal is Y=ACG _t X'=ACG _t G _t ^-1 C ^-1 X=AX, where A is the direction vector, C is the mutual coupling coefficient matrix of the receiving link antenna array, and G _t is the transmitting link gain Error matrix; where far field is the source of far field correction. 2. The method according to claim 1, wherein the amplitude/phase gain matrix and the mutual coupling coefficient matrix of the receiving link antenna array are estimated by using near-field coupling antennas and far-field correction sources. 3. The method according to claim 1, wherein the estimation of the mutual coupling coefficient matrix C of the receiving link antenna array is specifically: The estimation of the mutual coupling coefficient matrix C is simplified to the estimation of the representation vector c of the mutual coupling coefficient matrix, If n=2k+1, k=1,2,...; c={1 c ₁ c ₂ ... c _k c _k ... c ₂ c ₁ }; If n=2k, k=1,2,..; c={1 c ₁ c ₂ ... c _k-1 c _k c _k-1 ... c ₂ c ₁ }; Among them, c _i is the coupling coefficient between two array elements whose angle difference to the center of the circle is (2π/n)i, i=1,2,...,k; n is the number of antenna arrays, and k is the corresponding independent number of elements.