CN112630726A - Arc array positioning method and system - Google Patents
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Abstract
The invention relates to the field of antenna array positioning, in particular to an arc-shaped array positioning method and system. The arc array positioning method comprises the following steps: step S1, controlling the antenna array element to receive signals; step S2, frequency offset correction is carried out; step S3, calculating the space spectrum peak value and the arrival angle estimation result of each group of received signals according to the signals after the frequency offset correction of each antenna array element of each group of arc-shaped arrays; step S4, obtaining a maximum spatial spectrum peak value and a corresponding arrival angle estimation result; step S5, determining the position of the arc array corresponding to the maximum spatial spectrum peak value in the uniform circular array; and step S6, determining the arrival angle estimation result of the uniform circular array according to the arrival angle estimation result corresponding to the maximum spatial spectrum peak value and the position of the arc array in the uniform circular array. The beneficial effects of this technical scheme do: under the condition that the number of the adopted antenna array elements is the same, the method can improve the estimation precision of the arrival angle, and simultaneously adopts a switching array mode, thereby being easy to realize engineering.
Description
Technical Field
The invention relates to the field of antenna array positioning, in particular to an arc-shaped array positioning method and system.
Background
Due to the wide application of antenna arrays in various fields of modern society, the analysis and integration of array antennas are becoming important issues of research. The analysis problem of the array antenna is mainly to obtain array factors of the array according to basic parameters (array element number, array element position, excitation amplitude, phase and the like) of the array antenna, and further obtain the radiation performance of the array antenna, such as information of main lobe beam direction, main lobe width, side lobe level, null, directivity and the like. The comprehensive problem of the array antenna is the inverse problem of the analysis of the array antenna, that is, the basic array information such as the number of array elements, the position, the excitation amplitude, the phase and the like required for achieving the performance of a given directional diagram is obtained according to the required radiation characteristics of the array, and the comprehensive problem of the array is also called as the design of the array antenna.
The performance of the array antenna system mainly depends on a baseband algorithm and an array structure, so that it is necessary to design a reasonable antenna array structure while exploring a high-efficiency baseband algorithm, and therefore, a reasonable DOA (Direction of arrival) estimation algorithm using the antenna array structure and the baseband becomes a key problem mainly affecting the performance of the array antenna system. However, in the prior art, the performance of the arrival angle estimation algorithm is greatly influenced by the antenna array structure, and meanwhile, the complexity of the arrival angle estimation algorithm is increased sharply along with the increase of the number of the utilized antenna array elements.
Disclosure of Invention
Aiming at the problems in the prior art, an arc array positioning method is provided, and is applied to a uniform circular array, wherein the uniform circular array comprises 4K antenna array elements which are distributed on the circumference at equal angular intervals, and the value range of K is more than or equal to 1;
the arc antenna array positioning method comprises the following steps:
step S1, controlling the rf channel where each antenna element is located to switch to a receiving channel to receive signals one by one in a preset sequence;
step S2, performing signal preprocessing on the signals received by the antenna elements, and then performing frequency offset correction processing to obtain frequency offset corrected signals corresponding to each antenna element;
step S3, dividing every K adjacent antenna array elements to obtain 4K groups of arc arrays, and calculating the spatial spectrum peak value and arrival angle estimation result of each group of received signals according to the signals of each antenna array element of each group of arc arrays after frequency offset correction;
step S4, obtaining a maximum spatial spectrum peak value and a corresponding arrival angle estimation result according to the spatial spectrum peak value and the arrival angle estimation result of each group of received signals;
step S5, determining the positions of a corresponding group of arc arrays in the uniform circular array according to the maximum spatial spectrum peak value and the corresponding arrival angle estimation result;
step S6, determining an arrival angle estimation result of the uniform circular array according to the arrival angle estimation result corresponding to the maximum spatial spectrum peak and the position of the arc array in the uniform circular array.
Preferably, before the step S1 is executed, the method further includes the following steps:
step A1, selecting a radio frequency channel where the antenna array element at a preset position is located, switching the radio frequency channel into a receiving channel, closing the radio frequency channels where the other antenna arrays are located, and sending a reference single tone signal with a synchronization head through an external sending end;
step a2, determining whether all the antenna elements at the predetermined positions can be matched with the reference tone signal synchronously:
if yes, go to step S1;
if not, the process is exited.
Preferably, the step S2 includes:
step S21, performing analog-to-digital conversion on the signal received by each antenna array element to obtain a received signal after analog-to-digital conversion;
step S22, eliminating the received signals when the radio frequency channel of the antenna array element corresponding to the received signals after analog-to-digital conversion is in a switching state, and obtaining filtered received signals;
step S23, obtaining the frequency offset of each antenna array element according to the filtered received signal, calculating a frequency offset mean value according to the frequency offset of each antenna array element, and performing frequency offset correction on the filtered received signal according to the frequency offset mean value.
Preferably, said received signal of each of said antenna elements comprises at least twice the period of the signal;
the frequency offset is expressed by the following formula:
wherein,
Δ ε is used to represent the frequency offset;
r (m) represents a signal belonging to a previous cycle among the signals;
r (m + Nt) is used for representing a signal belonging to a next period in the signals;
m is used to represent the number of sample points of the signal and 2N is used to represent the total number of sample points.
Preferably, the step S3 includes:
step S31, calculating the steering vector of each group of received signals and the noise characteristic vector related to noise according to the signals after the frequency offset correction of each antenna array element of each group of arc array;
step S32, acquiring a noise subspace corresponding to the noise feature vector;
step S33, obtaining a spatial spectrum according to the orthogonality of the noise subspace and the array manifold vector, and performing spectrum peak search on the spatial spectrum to obtain a spatial spectrum peak value and an arrival angle estimation result of each group of received signals.
Preferably, the following formula is adopted to determine the position of the arc array in the uniform circular array:
wherein,
q is used to indicate the sequence number of the arc array in all the arc arrays, and q is 1,2,3,4, … … 4 k.
Preferably, the following formula is adopted to determine the estimation result of the arrival angle of the uniform circular array:
wherein,
gamma is used for representing the estimation result of the arrival angle of the uniform circular array;
γqand is used for representing the estimation result of the arrival angle corresponding to the maximum spatial spectrum peak.
An arc array positioning system is applied to a uniform circular array, wherein the uniform circular array comprises 4K antenna array elements which are distributed on the circumference at equal angle intervals, and the value range of K is more than or equal to 1;
the arc antenna array positioning system comprises:
the receiving switches control the radio frequency channel where each antenna array element is located to be switched into a receiving channel one by one according to a preset sequence so as to receive signals;
a correction processing module, connected to the receiving switch, for performing signal preprocessing on the signals received by the antenna array elements and then performing frequency offset correction processing on the signals to obtain frequency offset corrected signals corresponding to each antenna array element;
the first processing module is connected with the correction processing module and used for dividing every K adjacent antenna array elements to obtain 4K groups of arc arrays, and calculating a space spectrum peak value and an arrival angle estimation result of each group of received signals according to the signals of each antenna array element of each group of arc arrays after frequency offset correction;
a second processing module, connected to the first processing module, for obtaining a maximum spatial spectrum peak value and a corresponding arrival angle estimation result according to the spatial spectrum peak value and the arrival angle estimation result of each group of received signals;
the third processing module is connected with the second processing module and used for determining the positions of a group of corresponding arc arrays in the uniform circular array according to the maximum spatial spectrum peak value and the corresponding arrival angle estimation result;
and the positioning module is connected with the second processing module and the third processing module and used for determining the estimation result of the arrival angle of the uniform circular array according to the estimation result of the arrival angle corresponding to the maximum spatial spectrum peak value and the position of the arc array in the uniform circular array.
Preferably, the mobile terminal further comprises a detection module, the detection module is connected to the 4K receiving switches, and the detection module comprises:
the antenna array comprises a selecting unit, a receiving unit and a transmitting unit, wherein the selecting unit is used for selecting a radio frequency channel where the antenna array element at a preset position is located to be switched into a receiving channel, closing the radio frequency channels where the other antenna arrays are located and transmitting a reference single tone signal with a synchronous head through an external transmitting end;
the judging unit is connected with the selecting unit and used for judging whether all the antenna array elements at the preset positions can be synchronously matched with the reference single tone signal or not and generating a judging result;
and the execution unit is connected with the judgment unit and used for receiving the judgment result and controlling the receiving switch to be used for controlling the radio frequency channel where each antenna array element is located to be switched into a receiving channel one by one according to a preset sequence so as to receive the signals when the judgment result indicates that all the receiving array elements can receive the signals.
Preferably, the correction processing module includes:
the analog-to-digital conversion unit is used for performing analog-to-digital conversion on the signals received by each antenna array element to obtain received signals after the analog-to-digital conversion;
the eliminating unit is connected with the analog-to-digital conversion unit and used for eliminating the received signals when the radio frequency channel where the corresponding antenna array element is located in the received signals after analog-to-digital conversion is in a switching state to obtain screened received signals;
and the frequency offset correcting unit is connected with the eliminating unit and used for acquiring the frequency offset of each antenna array element according to the screened receiving signals, calculating a frequency offset mean value according to the frequency offset of each antenna array element, and performing frequency offset correction according to the screened receiving signals of the frequency offset mean value.
Preferably, the first processing module includes:
the first processing unit is used for calculating a steering vector of each group of received signals and a noise characteristic vector related to noise according to the signals after the frequency offset correction of each antenna array element of each group of the arc array;
the second processing unit is connected with the first processing unit and used for acquiring a noise subspace corresponding to the noise characteristic vector;
and the third processing unit is connected with the second processing unit and used for acquiring a spatial spectrum according to the orthogonality of the noise subspace and the array manifold vector, and performing spectral peak search on the spatial spectrum to obtain a spatial spectrum peak value and an arrival angle estimation result of each group of received signals.
The technical scheme has the following advantages or beneficial effects: under the condition that the number of the adopted antenna array elements is the same, the method can improve the estimation precision of the arrival angle, and simultaneously adopts a switching array mode, thereby being easy to realize engineering.
Drawings
Fig. 1 is a schematic flow chart of a method for positioning an arc antenna array according to a preferred embodiment of the present invention;
fig. 2 is a schematic diagram of an antenna element in a preferred embodiment of the present invention;
fig. 3 is a schematic flowchart of the arc antenna array positioning method according to the preferred embodiment of the present invention before step S1 is executed;
fig. 4 is a schematic flowchart of step S2 in the method for positioning an arc antenna array according to the preferred embodiment of the present invention;
fig. 5 is a schematic flowchart of step S3 in the method for positioning an arc antenna array according to the preferred embodiment of the present invention;
fig. 6 is a schematic structural diagram of an arc antenna array positioning system according to a preferred embodiment of the present invention;
fig. 7 is a schematic structural diagram of a calibration processing module of the curved antenna array positioning system according to the preferred embodiment of the present invention;
fig. 8 is a schematic structural diagram of a first processing module of the curved antenna array positioning system according to the preferred embodiment of the present invention;
FIG. 9 is a diagram of spectral peaks of a prior art uniform circular array based spatial spectrum in a preferred embodiment of the present invention;
fig. 10 is a schematic diagram of the spectral peaks of the spatial spectrum based on the uniform circular array in the preferred embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
An arc array positioning method is applied to a uniform circular array, the uniform circular array comprises 4K antenna array elements which are distributed on the circumference at equal angle intervals, and the value range of K is that K is more than or equal to 1;
as shown in fig. 1, the method for positioning an arc antenna array includes:
step S1, controlling the rf channels of each antenna element to switch to the receiving channels one by one in a preset sequence to receive signals;
step S2, after signal preprocessing is carried out on the signals received by the antenna array elements, frequency offset correction processing is carried out to obtain frequency offset corrected signals corresponding to each antenna array element;
step S3, dividing every K adjacent antenna array elements to obtain 4K groups of arc arrays, and calculating the space spectrum peak value and arrival angle estimation result of each group of received signals according to the signals after the frequency offset correction of each antenna array element of each group of arc arrays;
step S4, obtaining a maximum spatial spectrum peak and a corresponding arrival angle estimation result according to the spatial spectrum peak and the arrival angle estimation result of each group of received signals;
step S5, determining the positions of a corresponding group of arc arrays in a uniform circular array according to the maximum space spectrum peak value and the corresponding arrival angle estimation result;
and step S6, determining the arrival angle estimation result of the uniform circular array according to the arrival angle estimation result corresponding to the maximum spatial spectrum peak value and the position of the arc array in the uniform circular array.
Specifically, in consideration of the fact that the accuracy of the estimation result is poor when the arrival angle estimation algorithm of the uniform circular array is adopted in the prior art, the invention provides the arc array positioning method, through the steps S1-S6, under the condition that the number of antenna array elements adopted by the arrival angle estimation algorithm in the prior art is the same, the estimation accuracy of the arrival angle can be improved, and the switching array mode is also adopted in the invention, so that the engineering implementation is easy. In the invention:
in step S1, the radio frequency channels in which each antenna array element is located are controlled to be switched to receiving channels one by one in a preset sequence to receive signals, specifically, all the antenna array elements on the uniform circular array are numbered as 1,2,3, and 4 … 4K clockwise in sequence, the radio frequency channel in which each antenna array element is located is controlled to be switched to a receiving channel one by one, that is, the radio frequency channel in which antenna array element 1 is switched is the receiving channel to receive signals, other antenna array elements at this time are not received, then the receiving channel in antenna array element 1 is closed, the radio frequency channel in which antenna array element 2 is switched correspondingly is the receiving channel to receive signals, and so on, from antenna array element 1, antenna array element 2, antenna array element 3 … … to antenna array element 4K.
In step S2, the signals received by the antenna elements are subjected to signal preprocessing and then to frequency offset correction processing to obtain frequency offset corrected signals corresponding to each antenna element, specifically, the signals received by the antenna elements 1,2,3,4 … 4K are preprocessed and then subjected to frequency offset processing to remove inaccurate, affected and easily-caused result deviation signals in the signals, so as to improve the accuracy of the final positioning result.
In step S3, every K adjacent antenna array elements are divided to obtain 4K groups of arc arrays, and a spatial spectrum peak value and an arrival angle estimation result of each group of received signals are calculated according to a signal after frequency offset correction of each antenna array element of each group of arc arrays, specifically, as shown in fig. 2, a uniform circular array is divided into 4K groups of arc arrays, each group includes adjacent K antenna array elements, wherein one division manner is that the deviation of the adjacent arc arrays is 1 antenna array element, that is: the first group of arc-shaped arrays are antenna array element 1, antenna array element 2, antenna array element 3 … … -antenna array element K, the second group of arc-shaped arrays are antenna array element 2, antenna array element 3, antenna array element 4 … … -antenna array element K +1, the division mode is the most preferable division mode, 4K groups of arc-shaped arrays can be obtained after division, and the corresponding positioning result is the most accurate.
In step S4, a maximum spatial spectrum peak and a corresponding arrival angle estimation result are obtained according to the spatial spectrum peak and arrival angle estimation result of each group of received signals, specifically, the received signals are divided into 4K groups of arc arrays according to the division result, and after the spatial spectrum peak and arrival angle estimation result of each group of arc arrays are obtained, a maximum spatial spectrum peak and an arrival angle estimation result corresponding to the maximum spatial spectrum peak are obtained according to all the spatial spectrum peak and arrival angle estimation results.
In step S5, the positions of the corresponding arc arrays in the uniform circular array are determined according to the maximum spatial spectrum peak and the corresponding arrival angle estimation result, specifically, each arc array 1,2,3,4 … 4K has a spatial spectrum peak and a corresponding arrival angle estimation result, and if the K-th arc array corresponding to the maximum spatial spectrum peak is selected, the positions of the K-th arc array and the integrated uniform circular array are obtained.
In step S6, the arrival angle estimation result of the uniform circular array is determined according to the arrival angle estimation result corresponding to the maximum spatial spectrum peak and the position of the arc array in the uniform circular array.
In a preferred embodiment of the present invention, as shown in fig. 3, before the step S1 is executed, the method further includes the following steps:
step A1, selecting the radio frequency channel where the antenna array element at the preset position is located to switch to a receiving channel, closing the radio frequency channels where the other antenna arrays are located, and sending a reference single tone signal with a synchronization head through an external sending end;
step A2, judging whether all antenna elements at the preset positions can be synchronously matched with the reference single tone signal:
if yes, go to step S1;
if not, the process is exited.
Specifically, to ensure that all antennas can receive signals to achieve angle-of-arrival estimation of the signals, before step S1 is performed, steps a1 to a2 are further included to achieve synchronous matching of the signals. That is, the positions of 0 °, 90 °, 180 °, and 270 ° in the uniform circular array may be used as predetermined positions, and the antenna 1, the antenna K +1, the antenna 2K +1, and the antenna 3K +1 located at the predetermined positions are controlled to receive the single-tone signal with the sync header, and whether synchronization matching can be achieved is determined, if yes, the antenna at any position on the uniform circular array can receive the signal, so that the steps S1-S6 may be performed, and the arrival angle is estimated.
In a preferred embodiment of the present invention, as shown in fig. 4, step S2 includes:
step S21, performing analog-to-digital conversion on the signal received by each antenna array element to obtain a received signal after analog-to-digital conversion;
step S22, eliminating the received signals when the radio frequency channel of the corresponding antenna array element in the received signals after analog-to-digital conversion is in a switching state, and obtaining the filtered received signals;
step S23, obtaining the frequency offset of each antenna array element according to the filtered received signal, calculating a frequency offset mean value according to the frequency offset of each antenna array element, and performing frequency offset correction according to the filtered received signal of the frequency offset mean value.
In a preferred embodiment of the present invention, the received signal of each antenna element comprises at least twice the period of the signal;
the frequency offset is expressed by the following formula:
wherein,
Δ ε is used to represent the frequency offset;
r (m) represents a signal belonging to a previous cycle in the signal;
r (m + Nt) is used for representing a signal belonging to a next period in the signals;
m is used to represent the number of sample points of the signal and 2N is used to represent the total number of sample points.
Specifically, each antenna lasts for t times of the time for completely receiving a single-tone signal of one period, wherein t is more than or equal to 2, the phase of the signal received by each antenna in each period is the same, the phase difference of the signals of adjacent periods received by one antenna is caused by the existence of carrier frequency synchronization error, and the signal of the first period received by one antenna is expressed as
r(m)＝s(m)*ejmΔε
Where m is 1,2,3,4, … … N, N is the number of sampling points of a tone signal in a complete period, s (m) is the tone signal to be transmitted, and Δ ∈ is the carrier frequency offset.
The signal received by the antenna in the second period is represented as
r(m+Nt)＝s(m+Nt)*ej(m+Nt)Δε
Is divided by the above formula to obtain
Since s (m + Nt) ═ s (m) can be obtained as a single tone signal with a complete period of the two received signals, the formula (3) can be simplified into
Q(m)＝ej(Nt)Δε
Can be obtained from the above formula
Δε＝arg(Q(m))/(Nt)
I.e., the frequency offset calculated for one antenna.
And by analogy, averaging the frequency offsets calculated by all the antennas to obtain a final frequency offset calculation result, and performing frequency offset correction on the received signal by using the final frequency offset calculation result.
In a preferred embodiment of the present invention, as shown in fig. 5, step S3 includes:
step S31, calculating the steering vector of each group of received signals and the noise characteristic vector related to the noise according to the signals after the frequency offset correction of each antenna array element of each group of arc array;
step S32, acquiring a noise subspace corresponding to the noise characteristic vector;
step S33, obtaining a spatial spectrum according to the orthogonality between the noise subspace and the array manifold vector, and performing a spectral peak search on the spatial spectrum to obtain a spatial spectral peak value and an arrival angle estimation result of each group of received signals.
It should be noted that the arrival angle estimation algorithm of the present invention can be applied to the scenario where multiple signal sources transmit signals, for example, when the number of signal sources is D, where D is greater than or equal to 1, and accordingly, the number of signal eigenvalues and eigenvectors is D, the number of noise eigenvalues and eigenvectors is K-D (K is the number of antenna elements in the arc array), and the noise in each channel is uncorrelated, then the noise correlation matrix is a diagonal matrix, and the uncorrelated noise has equal variance, that is, the number of signal sources is D
Wherein,
Rxxfor representing an array correlation matrix;
RSSfor representation as a source correlation matrix;
A＝[a(θ1)a(θ2)…a(θD)]for the purpose of representing a matrix of steering vectors,
i is used for representing an identity matrix;
Subsequently, an array correlation matrix R is obtainedxxFurther, D eigenvectors related to the signal and K-D eigenvectors related to the noise are obtained, and the eigenvector corresponding to the minimum eigenvalue is selected. For uncorrelated signals, the minimum eigenvalue is equal to the variance of the noise. A subspace consisting of the noise feature vectors is then constructed, namely:
E＝[e1 e2 … eK-D]
at angle of arrival theta1 θ2 … θDHere, the noise subspace eigenvector is orthogonal to the antenna array steering vector.
Correspondingly, a space spectrum is obtained according to the orthogonality of the noise subspace and the array manifold vector, and further the Euclidean distance d of the arrival angle of each signal source is obtained2＝a(θ)HEEHa(θ)＝0。
The distance expression is put into a denominator to obtain a spectral peak of an arrival angle, and a pseudospectrum of MUSIC is
Therefore, the arrival angle estimation result of each group of arc array DOA algorithm can be obtained. Correspondingly, when the number of the signal sources is 1, the arrival angle estimation result of each group of the arc array DOA algorithm can be correspondingly recorded as gammaq1. The steps S31 to S33 may be used for the arrival angle estimation of a single signal source, and may also be used for the arrival angle estimation of multiple signal sources, and the situation that the arrival angle estimation result cannot be obtained due to different environmental restrictions may not occur.
In a preferred embodiment of the present invention, the position of the arc array in the uniform circular array is determined using the following formula:
wherein,
q is used to indicate the sequence number of the arc array in all the arc arrays, and q is 1,2,3,4, … … 4 k.
In a preferred embodiment of the present invention, the following formula is used to determine the estimation result of the arrival angle of the uniform circular array:
wherein,
gamma is used for representing the estimation result of the arrival angle of the uniform circular array;
γqangle-of-arrival estimation for representing maximum spatial spectrum peak correspondenceAnd (6) obtaining the result.
Specifically, each group of arc-shaped arrays has a spatial spectrum peak value theta when aiming at one signal source1,θ2,……θ4kAnd corresponding angle of arrival estimate γ'1,γ′2,……γ′4kBy comparison of theta1,θ2,……θ4kObtaining the maximum space spectrum peak value thetaqAnd corresponding angle of arrival estimation result gammaqThe corresponding arc array is a q-th array, and the position of the array in the uniform circular array is
The arrival angle estimation result γ of the uniform circular array can be determined thereby.
As shown in fig. 6, an arc array positioning system is applied to a uniform circular array, which includes 4K antenna elements distributed on a circumference at equal angular intervals, where K is equal to or greater than 1;
the arc antenna array positioning system comprises:
the receiving switches 01 are respectively connected with an antenna array element, and the receiving switches 01 control the radio frequency channel where each antenna array element is located to be switched into a receiving channel one by one according to a preset sequence so as to receive signals;
a correction processing module 02 connected to the receiving switch 01, for performing signal preprocessing on the signals received by the antenna array elements and then performing frequency offset correction processing on the signals to obtain frequency offset corrected signals corresponding to each antenna array element;
the first processing module 03 is connected to the correction processing module 02 and configured to divide every K adjacent antenna array elements to obtain 4K groups of arc arrays, and calculate a spatial spectrum peak value and an arrival angle estimation result of each group of received signals according to the frequency offset-corrected signal of each antenna array element of each group of arc arrays;
a second processing module 04, connected to the first processing module 03, for obtaining a maximum spatial spectrum peak value and a corresponding arrival angle estimation result according to the spatial spectrum peak value and the arrival angle estimation result of each group of received signals;
the third processing module 05 is connected to the second processing module 04 and configured to determine positions of the corresponding arc arrays in the uniform circular array according to the maximum spatial spectrum peak value and the corresponding arrival angle estimation result;
and the positioning module 06 is connected to the second processing module 04 and the third processing module 05, and is configured to determine an arrival angle estimation result of the uniform circular array according to the arrival angle estimation result corresponding to the maximum spatial spectrum peak and the position of the arc array in the uniform circular array.
Specifically, the invention provides an arc array positioning system, which can improve the estimation accuracy of the arrival angle by using a receiving switch 01, a correction processing module 02, a first processing module 03, a second processing module 04, a third processing module 05 and a positioning module 06 under the condition that the number of antenna array elements is the same as that of the arrival angle estimation algorithm in the prior art, and the invention also adopts a switching array mode, thereby being easy for engineering realization.
In a preferred embodiment of the present invention, the present invention further includes a detection module, the detection module is connected to the 4K receiving switches 01, and the detection module includes:
the antenna array comprises a selecting unit, a receiving unit and a transmitting unit, wherein the selecting unit is used for selecting a radio frequency channel where an antenna array element at a preset position is located to be switched into a receiving channel, closing the radio frequency channels where other antenna arrays are located and transmitting a reference single tone signal with a synchronous head through an external transmitting end;
the judging unit is connected with the selecting unit and used for judging whether all antenna array elements at the preset positions can be synchronously matched with the reference single tone signal or not and generating a judging result;
and the execution unit is connected with the judgment unit and used for receiving the judgment result, and controlling the receiving switch 01 to be used for controlling the radio frequency channel where each antenna array element is located to be switched into the receiving channel one by one according to a preset sequence to receive the signals when the judgment result indicates that all the receiving array elements can receive the signals.
Specifically, when the method is applied to the module, the single-tone signals with the synchronization heads are received by the antenna 1, the antenna K +1, the antenna 2K +1 and the antenna 3K +1 which correspond to the positions of 0 °, 90 °, 180 ° and 270 ° in the uniform circular array through the selection unit, and whether synchronous matching can be achieved is judged through the judgment unit, if yes, the antenna at any position on the uniform circular array can receive the signals, and therefore the arrival angle can be estimated.
In a preferred embodiment of the present invention, as shown in fig. 7, the correction processing module 02 includes:
an analog-to-digital conversion unit 021, configured to perform analog-to-digital conversion on a signal received by each antenna array element, and obtain a received signal after the analog-to-digital conversion;
a rejecting unit 022, connected to the analog-to-digital conversion unit 021, configured to reject a received signal received when a radio frequency channel in which the antenna array element corresponding to the received signal after analog-to-digital conversion is located is in a switching state, so as to obtain a filtered received signal;
and the frequency offset correction unit 023 is connected with the rejection unit 022 and is configured to obtain the frequency offset of each antenna array element according to the filtered received signal, calculate a frequency offset mean value according to the frequency offset of each antenna array element, and perform frequency offset correction according to the received signal after the frequency offset mean value screening.
Specifically, when the desired signal is synchronously matched, the switch is switched, the sequence of the switch is antenna 1, antenna 2, antenna 3, antenna 4, antenna 5, antenna 6, …, and antenna 4k, the receiving time of each antenna is T, where T is T times the time for completely receiving a single tone signal of one period, where T is a positive integer greater than or equal to 2, and the received analog signal is sent to the a/D analog-to-digital conversion unit 021.
Since the antenna switching process may cause signal quality degradation, the removing unit 022 is required to remove the signal received when the antenna is switched, so as to obtain a received signal with better quality.
Then, the removed received signal is sent to a frequency offset correction unit 023 for frequency offset correction.
In a preferred embodiment of the present invention, the received signal of each antenna element includes at least twice the period of the signal;
the frequency offset is expressed by the following formula:
wherein,
Δ ε is used to represent the frequency offset;
r (m) represents a signal belonging to a previous cycle in the signal;
r (m + Nt) is used for representing a signal belonging to a next period in the signals;
m is used to represent the number of sample points of the signal and 2N is used to represent the total number of sample points.
In particular, as applied to the above-described modules,
in a preferred embodiment of the present invention, as shown in fig. 8, the first process module 03 includes:
a first processing unit 031, configured to calculate a steering vector of each group of received signals and a noise eigenvector related to noise according to the frequency offset-corrected signal of each antenna array element of each group of arc arrays;
the second processing unit 032, connected to the first processing unit 031, is configured to obtain a noise subspace corresponding to the noise feature vector;
and the third processing unit 033, connected to the second processing unit 032, is configured to obtain a spatial spectrum according to orthogonality between the noise subspace and the array manifold vector, and perform spectrum peak search on the spatial spectrum to obtain a spatial spectrum peak value and an arrival angle estimation result of each group of received signals.
In a preferred embodiment of the invention, the third processing module 05 determines the position of the arc array in the uniform circular array:
wherein,
gamma is used for representing the position of the arc array in the uniform circular array;
q is used to indicate the sequence number of the arc array in all the arc arrays, and q is 1,2,3,4, … … 4 k.
In a preferred embodiment of the present invention, the positioning module 06 determines the estimation result of the arrival angle of the uniform circular array by using the following formula:
wherein,
gamma is used for representing the estimation result of the arrival angle of the uniform circular array;
γqand is used for representing the estimation result of the arrival angle corresponding to the maximum spatial spectrum peak.
Examples
When the uniform circular array includes 8 antenna elements, if a signal source is located at the position of 20 degrees, the spatial spectrum peak search result in the prior art is shown in fig. 9, while the spatial spectrum peak search result obtained by the technical scheme of the present invention is shown in fig. 10, and then the result obtained after processing is closer to the set 20 degrees, so that the present invention can obtain a more accurate arrival angle estimation result.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
Claims (11)
1. An arc array positioning method is characterized by being applied to a uniform circular array, wherein the uniform circular array comprises 4K antenna array elements which are distributed on the circumference at equal angle intervals, and the value range of K is that K is more than or equal to 1;
the arc antenna array positioning method comprises the following steps:
step S1, controlling the rf channel where each antenna element is located to switch to a receiving channel to receive signals one by one in a preset sequence;
step S2, performing signal preprocessing on the signals received by the antenna elements, and then performing frequency offset correction processing to obtain frequency offset corrected signals corresponding to each antenna element;
step S3, dividing every K adjacent antenna array elements to obtain 4K groups of arc arrays, and calculating the spatial spectrum peak value and arrival angle estimation result of each group of received signals according to the signals of each antenna array element of each group of arc arrays after frequency offset correction;
step S4, obtaining a maximum spatial spectrum peak value and a corresponding arrival angle estimation result according to the spatial spectrum peak value and the arrival angle estimation result of each group of received signals;
step S5, determining the positions of a corresponding group of arc arrays in the uniform circular array according to the maximum spatial spectrum peak value and the corresponding arrival angle estimation result;
step S6, determining an arrival angle estimation result of the uniform circular array according to the arrival angle estimation result corresponding to the maximum spatial spectrum peak and the position of the arc array in the uniform circular array.
2. The arc array positioning method according to claim 1, further comprising, before the step S1 is performed, the steps of:
step A1, selecting a radio frequency channel where the antenna array element at a preset position is located, switching the radio frequency channel into a receiving channel, closing the radio frequency channels where the other antenna arrays are located, and sending a reference single tone signal with a synchronization head through an external sending end;
step a2, determining whether all the antenna elements at the predetermined positions can be matched with the reference tone signal synchronously:
if yes, go to step S1;
if not, the process is exited.
3. The arc array positioning method according to claim 1, wherein the step S2 includes:
step S21, performing analog-to-digital conversion on the signal received by each antenna array element to obtain a received signal after analog-to-digital conversion;
step S22, eliminating the received signals when the radio frequency channel of the antenna array element corresponding to the received signals after analog-to-digital conversion is in a switching state, and obtaining filtered received signals;
step S23, obtaining the frequency offset of each antenna array element according to the filtered received signal, calculating a frequency offset mean value according to the frequency offset of each antenna array element, and performing frequency offset correction on the filtered received signal according to the frequency offset mean value.
4. The arc array positioning method of claim 3, wherein the received signal of each antenna element comprises at least twice the period of the signal;
the frequency offset is expressed by the following formula:
wherein,
Δ ε is used to represent the frequency offset;
r (m) represents a signal belonging to a previous cycle among the signals;
r (m + Nt) is used for representing a signal belonging to a next period in the signals;
m is used to represent the number of sample points of the signal and 2N is used to represent the total number of sample points.
5. The arc array positioning method according to claim 1, wherein the step S3 includes:
step S31, calculating the steering vector of each group of received signals and the noise characteristic vector related to noise according to the signals after the frequency offset correction of each antenna array element of each group of arc array;
step S32, acquiring a noise subspace corresponding to the noise feature vector;
step S33, obtaining a spatial spectrum according to the orthogonality of the noise subspace and the array manifold vector, and performing spectrum peak search on the spatial spectrum to obtain a spatial spectrum peak value and an arrival angle estimation result of each group of received signals.
6. The arc array positioning method of claim 1, wherein the position of the arc array in the uniform circular array is determined using the following formula:
wherein,
q is used to indicate the sequence number of the arc array in all the arc arrays, and q is 1,2,3,4, … … 4 k.
7. The arc array positioning method of claim 1, wherein the arrival angle estimation result of the uniform circular array is determined by using the following formula:
wherein,
gamma is used for representing the estimation result of the arrival angle of the uniform circular array;
γqused for representing the estimation result of the arrival angle corresponding to the maximum spatial spectrum peak value。
8. An arc array positioning system is applied to a uniform circular array and is characterized in that the arc array positioning system is applied to the uniform circular array, the uniform circular array comprises 4K antenna array elements which are distributed on the circumference at equal angular intervals, and the value range of K is more than or equal to 1;
the arc antenna array positioning system comprises:
the receiving switches control the radio frequency channel where each antenna array element is located to be switched into a receiving channel one by one according to a preset sequence so as to receive signals;
a correction processing module, connected to the receiving switch, for performing signal preprocessing on the signals received by the antenna array elements and then performing frequency offset correction processing on the signals to obtain frequency offset corrected signals corresponding to each antenna array element;
the first processing module is connected with the correction processing module and used for dividing every K adjacent antenna array elements to obtain 4K groups of arc arrays, and calculating a space spectrum peak value and an arrival angle estimation result of each group of received signals according to the signals of each antenna array element of each group of arc arrays after frequency offset correction;
a second processing module, connected to the first processing module, for obtaining a maximum spatial spectrum peak value and a corresponding arrival angle estimation result according to the spatial spectrum peak value and the arrival angle estimation result of each group of received signals;
the third processing module is connected with the second processing module and used for determining the positions of a group of corresponding arc arrays in the uniform circular array according to the maximum spatial spectrum peak value and the corresponding arrival angle estimation result;
and the positioning module is connected with the second processing module and the third processing module and used for determining the estimation result of the arrival angle of the uniform circular array according to the estimation result of the arrival angle corresponding to the maximum spatial spectrum peak value and the position of the arc array in the uniform circular array.
9. An arc array positioning system as in claim 8, further comprising a detection module, said detection module being connected to 4K receiving switches, said detection module comprising:
the antenna array comprises a selecting unit, a receiving unit and a transmitting unit, wherein the selecting unit is used for selecting a radio frequency channel where the antenna array element at a preset position is located to be switched into a receiving channel, closing the radio frequency channels where the other antenna arrays are located and transmitting a reference single tone signal with a synchronous head through an external transmitting end;
the judging unit is connected with the selecting unit and used for judging whether all the antenna array elements at the preset positions can be synchronously matched with the reference single tone signal or not and generating a judging result;
and the execution unit is connected with the judgment unit and used for receiving the judgment result and controlling the receiving switch to be used for controlling the radio frequency channel where each antenna array element is located to be switched into a receiving channel one by one according to a preset sequence so as to receive the signals when the judgment result indicates that all the receiving array elements can receive the signals.
10. An arcuate array positioning system as set forth in claim 8, wherein said calibration processing module comprises:
the analog-to-digital conversion unit is used for performing analog-to-digital conversion on the signals received by each antenna array element to obtain received signals after the analog-to-digital conversion;
the eliminating unit is connected with the analog-to-digital conversion unit and used for eliminating the received signals when the radio frequency channel where the corresponding antenna array element is located in the received signals after analog-to-digital conversion is in a switching state to obtain screened received signals;
and the frequency offset correcting unit is connected with the eliminating unit and used for acquiring the frequency offset of each antenna array element according to the screened receiving signals, calculating a frequency offset mean value according to the frequency offset of each antenna array element, and performing frequency offset correction according to the screened receiving signals of the frequency offset mean value.
11. An arcuate array positioning system as set forth in claim 10, wherein said first processing module includes:
the first processing unit is used for calculating a steering vector of each group of received signals and a noise characteristic vector related to noise according to the signals after the frequency offset correction of each antenna array element of each group of the arc array;
the second processing unit is connected with the first processing unit and used for acquiring a noise subspace corresponding to the noise characteristic vector;
and the third processing unit is connected with the second processing unit and used for acquiring a spatial spectrum according to the orthogonality of the noise subspace and the array manifold vector, and performing spectral peak search on the spatial spectrum to obtain a spatial spectrum peak value and an arrival angle estimation result of each group of received signals.
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