Signal processing method and device in space-frequency anti-interference system

Abstract

The embodiment of the present application discloses a signal processing method and device in a space-frequency anti-interference system. The method comprises: obtaining the frequency domain signal of the nth beam at K frequency points; correcting the frequency domain signal of each frequency point according to the carrier phase correction value corresponding to each frequency point, and obtaining K corrected frequency domain signals, wherein the carrier phase correction value is determined according to the error transfer function corresponding to each element in the antenna array at each frequency point; using the corrected K frequency domain signals, generating the time domain signal of the nth beam; wherein n=1,2,3,…,N, and N and K are both integers greater than or equal to 2.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of signal processing, and more particularly to a signal processing method and device in a space-frequency anti-interference system. Background Art

[0002] In a complex electromagnetic environment, there is a large amount of electromagnetic interference in the signal received by the receiver. In order to ensure that the receiver can be used for precise positioning, measurement and other applications, it is necessary to suppress strong suppression interference. There are many anti-interference methods in related technologies, such as time domain anti-interference, frequency domain anti-interference, space domain anti-interference, space-time anti-interference, space-frequency anti-interference and other methods.

[0003] In the related art, the space-frequency anti-interference method is implemented by the following methods, including:

[0004] The input signal received by the antenna array is divided into several frequency bands, and array processing is performed on each frequency band. The sampled value after each array element processing is then subjected to Fast Fourier Transform (FFT) to obtain a frequency domain signal. The weight vector of each frequency domain signal is calculated in the frequency domain. Finally, the frequency domain signal is subjected to Inverse Fast Fourier Transform (IFFT) to obtain a time domain signal.

[0005] In practical applications, the effect of the above-mentioned space-frequency anti-interference method needs to be further improved. Summary of the invention

[0006] In order to solve any of the above technical problems, an embodiment of the present application provides a signal processing method and device in a space-frequency anti-interference system.

[0007] In order to achieve the purpose of the embodiment of the present application, the embodiment of the present application provides a signal processing method in a space-frequency anti-interference system, including:

[0008] Obtain the frequency domain signal of the nth beam at K frequency points;

[0009] Correct the frequency domain signal of each frequency point according to the carrier phase correction value corresponding to each frequency point to obtain K corrected frequency domain signals, wherein the carrier phase correction value is determined according to the error transfer function corresponding to each array element in the antenna array at each frequency point;

[0010] Using the corrected K frequency domain signals, a time domain signal of the nth beam is generated;

[0011] Wherein, n=1, 2, 3, ..., N, and N and K are both integers greater than or equal to 2.

[0012] A storage medium stores a computer program, wherein the computer program is configured to execute the method described above when running.

[0013] A signal processing device in a space-frequency anti-interference system comprises a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the method described above.

[0014] One of the above technical solutions has the following advantages or beneficial effects:

[0015] The carrier phase of the frequency domain signal is corrected to improve the accuracy of the frequency domain signal and achieve the purpose of high-precision anti-interference.

[0016] Other features and advantages of the embodiments of the present application will be described in the subsequent description, and partly become apparent from the description, or can be understood by implementing the embodiments of the present application. The purpose and other advantages of the embodiments of the present application can be achieved and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide further understanding of the technical solutions of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the embodiments of the present application, they are used to explain the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions of the embodiments of the present application.

[0018] Figure 1 A schematic diagram of a space-frequency anti-interference system provided in an embodiment of the present application;

[0019] Figure 2 A flowchart of a signal processing method in a space-frequency anti-interference system provided in an embodiment of the present application;

[0020] Figure 3 A schematic diagram of a method for determining an error transfer function provided in an embodiment of the present application;

[0021] Figure 4 for Figure 1 Schematic diagram of the system performing space-frequency anti-interference. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present application more clear, the embodiments of the present application will be described in detail in conjunction with the accompanying drawings. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily.

[0023] Figure 1 Schematic diagram of a space-frequency anti-interference system provided in an embodiment of the present application. Figure 1As shown, the processing method of the system is as follows:

[0024] The beam of the nth satellite is received by M array elements in the antenna array to obtain an analog signal;

[0025] The following operations are performed on the analog signal received by each array element, including:

[0026] The analog signal is converted to digital form AD and sampled according to the preset sampling period Ts to obtain the digital signal x corresponding to the mth array element. m (n);

[0027] The digital signal x corresponding to the mth array element m (n) Perform K-point discrete Fourier transform to obtain a signal divided into K narrowbands in the frequency domain, and obtain the l-th snapshot number x of the analog signal of the m-th array element at the k-th frequency point mk (l);

[0028] Use the weight vector of the mth array element to perform weighted calculation on each snapshot number and output the weighted result y after processing mk (l);

[0029] After obtaining the weighted result y of the K frequency points corresponding to each array element mk (l) After that, the weighted result y from the same frequency point of M array elements is mk (l) performing signal synthesis to obtain a frequency domain signal corresponding to each frequency point;

[0030] By performing IDFT on the frequency domain signals of K frequency points, a time domain signal is obtained;

[0031] Wherein, n=1,2,3,……,N;k=1,2,3,……,K;m=1,2,3,……,M;

[0032] Wherein, N, K and M are all integers greater than or equal to 2.

[0033] Among them, the above system can be applied to anti-interference processing of digital multi-beam.

[0034] Based on the above system, the embodiment of the present application provides the following processing method, including:

[0035] Figure 2 A flowchart of a signal processing method in a space-frequency anti-interference system provided in an embodiment of the present application.

[0036] like Figure 2 As shown, the method includes:

[0037] Step 201: Obtain frequency domain signals of the nth beam at K frequency points.

[0038] Step 202: correct the frequency domain signal of each frequency point according to the carrier phase correction value corresponding to each frequency point to obtain K corrected frequency domain signals, wherein the carrier phase correction value is determined according to the error transfer function corresponding to each array element in the antenna array at each frequency point;

[0039] It can be known from the relevant technology that the acquired frequency domain signal is processed by the antenna array and transmitted through the RF channel. The above process will cause carrier phase error. Therefore, by determining the carrier phase correction value, the frequency domain signal can be effectively compensated and the signal quality can be improved.

[0040] Step 203: Generate a time domain signal of the nth beam using the corrected K frequency domain signals.

[0041] The method provided in the embodiment of the present application corrects the carrier phase of the frequency domain signal, improves the accuracy of the frequency domain signal, and achieves the purpose of high-precision anti-interference.

[0042] The method provided in the embodiment of the present application is described below:

[0043] In an exemplary embodiment, the carrier phase correction value of the kth frequency point is obtained by:

[0044] Obtain the error transfer function corresponding to the kth frequency point of the M array elements in the antenna array; obtain the weight corresponding to each array element at the kth frequency point from the weight vector corresponding to the M array elements;

[0045] Using the error transfer function and weight corresponding to each array element, weighted calculation is performed to obtain the kth frequency point f k The corresponding carrier phase correction value.

[0046] In the spatial domain anti-interference method, by setting corresponding weights for the error transfer function of each array element and performing weighted calculation of the error transfer functions of M array elements, the influence of the entire antenna array on the transmitted beam can be accurately obtained, and a more accurate carrier phase correction value can be obtained.

[0047] In an exemplary embodiment, the error transfer function corresponding to the m-th array element is determined according to the far-field phase direction function corresponding to the m-th array element and / or the error function of the radio frequency channel corresponding to the m-th array element.

[0048] Since the beam is received by the antenna array and transmitted through the RF channel, the phase error of the array element in the antenna array and the amplitude and phase errors of the RF channel will affect the signal quality of the received beam. Therefore, the far-field phase direction function corresponding to the mth array element and / or the error function of the RF channel corresponding to the mth array element can be used to determine the error transfer function corresponding to each array element to improve the accuracy of the error transfer function.

[0049] Figure 3 Schematic diagram of a method for determining an error transfer function provided in an embodiment of the present application. Figure 3 As shown, the error transfer function is jointly determined by the following two functions, wherein in practical applications, it can be determined according to one of the two functions, wherein one function is a far-field phase direction function determined based on the error information of the antenna array, and the other function is an error function of the RF channel determined by the error information of the RF channel.

[0050] Combination Figure 3 It can be seen that the far-field phase direction function corresponding to the m-th array element is determined according to at least one of the following parameters, including:

[0051] The phase center offset of the mth array element;

[0052] The elevation and azimuth angles of the mth element in the antenna array;

[0053] The three-dimensional coordinates of the mth element on the reflection plane of the antenna array.

[0054] The antenna array has a total of M array elements, which are evenly distributed in a circular array with element 1 at the center. Oxyz is a right-handed rectangular coordinate system established on the array surface, where the origin O is at the geometric center of the reflector plane, which is also the position of element 1. 1-M array elements are at an elevation angle of θ and a azimuth angle of The phase center offset and phase center variation in the direction can be accurately measured. The expression of the far-field phase pattern of the antenna array is shown in equation (1):

[0055]

[0056] In equation (1), (x, y, z) represents the three-dimensional coordinates of the antenna array, ψ 0 is the fixed phase center offset, b is the wave constant, and ξ is the measurement noise.

[0057] Since each element in the antenna array will produce phase center deviation, phase center change and amplitude-phase characteristic change errors; errors will also be introduced during the array synthesis process, so the expression of the 1-M far-field phase pattern of the antenna array can be found in equation (2):

[0058]

[0059] In formula (2), ψ m represents the phase center offset of the mth array element; (x m ,y m ,z m ) represents the three-dimensional coordinates of the mth element on the reflection plane of the antenna array, Respectively represent the elevation angle and azimuth angle corresponding to the mth array, θ q ∈[0°,90°]

[0060] Furthermore, each beam has its own corresponding far-field phase direction function of the mth array element;

[0061] The far-field phase direction function corresponding to the nth beam at the mth array element is determined according to the elevation angle and azimuth angle used by the mth array element in the antenna array to receive the nth beam.

[0062] Since different beams have different arrival angles, the angle information of the antenna array is also different when it receives beams from different satellites. By determining the far-field phase direction function of each array element corresponding to each beam, the accuracy of the carrier phase correction value can be improved.

[0063] Specifically, the expression of the far-field phase direction function of the nth beam corresponding to the mth array element is shown in formula (3):

[0064]

[0065] In formula (3), ψ m is the phase center offset of the mth array element, (x m ,y m ,z m ) represents the three-dimensional coordinate of the mth element on the reflection plane of the antenna array, θ n and They represent the elevation angle and azimuth angle used by the antenna array to receive the nth beam, k is the wave constant, and ξ is the measurement noise.

[0066] Combination Figure 3 It can be seen that the pointing error array errors introduced by the RF channel error mainly include: amplitude and phase errors between channels, mutual coupling between antennas, inconsistency between channel frequency bands, errors in array element position, etc. These errors are ultimately reflected in the relative amplitude and phase inconsistency between channels, ultimately leading to inaccurate signal pointing, thereby introducing pointing errors.

[0067] In an exemplary embodiment, the error function of the radio frequency channel corresponding to the mth array element is based on the transmission frequency point k k The amplitude error and / or phase error generated when the signal is determined.

[0068] Specifically, the error function of the RF channel is shown in expression (4):

[0069] A m ·S m (f k ); (4)

[0070] In formula (4), A m is the amplitude error caused by the RF channel corresponding to the mth array element, S m (f k ) is the RF channel corresponding to the mth array element at frequency f k The phase error caused.

[0071] According to the frequency response characteristics of the array antenna and the RF channel, the error transfer function of the mth corresponding array element is calculated, where the expression of the error transfer function is shown in formula (5):

[0072]

[0073] In formula (5), is the error transfer function of the mth array element, is the error function of the antenna array, A m S m (f k ) is the error function of the RF channel.

[0074] The amplitude and phase transmission characteristics of the antenna pattern in the corresponding space, as well as the amplitude and phase characteristics and channel frequency response characteristics of each RF channel, are used to calculate the amplitude and phase characteristic transfer function of each array element channel, thereby establishing the error function of the array channel corresponding to the spatial domain to improve the accuracy of the carrier phase correction value and provide support for achieving high-precision anti-interference.

[0075] The above describes the method for determining the error transfer function. The following describes the method for determining the weight of the error transfer function:

[0076] The weight vectors of the M array elements are determined according to the error transfer functions of the M array elements.

[0077] Unlike related technologies, the weight vector used in weighted calculation is determined according to the error transfer function corresponding to each of the M array elements to improve the accuracy of the weighted result.

[0078] Specifically, each beam has its own corresponding weight vector, wherein the weight vector of the nth beam is determined according to the space-frequency two-dimensional steering vector of the nth beam at the kth frequency point.

[0079] Specifically, the weight vector of each beam is determined by the following method, including:

[0080] For the beams of N visible satellites, a set of constraint equations corresponding to each beam at the kth frequency point is established;

[0081] Solve N sets of constraint equations to obtain N sets of weight vectors;

[0082] Each set of constraint equations includes a first constraint equation and a second constraint equation, wherein:

[0083] The first constraint equation is that the minimum value of the covariance matrix of the nth beam is equal to the value determined by the covariance matrix of the received signal at the kth frequency point and the weight vector of the nth beam at the kth frequency point;

[0084] The second constraint equation is that the value determined by the error function matrix of the mth array element, the space-frequency two-dimensional steering vector of the nth beam at the kth frequency point and the weight vector of the nth beam at the kth frequency point is equal to 1.

[0085] The determination of the weight vector is described in detail below:

[0086] For a uniform circular array centered on element 1, the space-frequency two-dimensional steering vector of the kth frequency point corresponding to the beam of the nth satellite is calculated according to the direction of the incoming wave of the satellite. The expression of the space-frequency two-dimensional steering vector is shown in equation (6):

[0087]

[0088] In formula (6), n=1,2,...N,γ m =2πm / M, c is the speed of light constant; where R represents the radius of the circular surface, where R=λ / 2, λ is the wavelength of the beam.

[0089] Determine the frequency domain covariance matrix R(f k ), which can be obtained from the sample covariance matrix Replace, see formula (7) for details:

[0090]

[0091] In equation (7), L represents the number of snapshots of frequency domain data, and x mk (l) represents the frequency point f corresponding to the sampling data of the mth array element after discrete Fourier transform k The lth snapshot number on .

[0092] Based on the arrival angle set of N visible satellites, the nth satellite corresponding to the frequency point f can be calculated k The digital beam constraint equations are as follows:

[0093]

[0094] In formula (8), w (n) (f k ) is the frequency point f corresponding to the nth satellite k The weight vector of , let μ be a constant, then

[0095] In an exemplary embodiment, the step of performing weighted calculation using the error transfer function and weight corresponding to each array element to obtain the carrier phase correction value corresponding to the kth frequency point includes:

[0096] Calculate the product of the value of the error transfer function of each array element and the weight of the respective error transfer function to obtain a calculation result;

[0097] The sum of the calculation results of the M array elements is calculated as the carrier phase correction value of the nth beam at the kth frequency point.

[0098] Based on the obtained error transfer function and weight vector, the expression of the carrier phase correction value of the nth beam at the kth frequency point can be obtained, specifically, formula (9):

[0099]

[0100] Calculate the corrected data after the frequency domain data is processed by the carrier phase correction value, specifically formula (10);

[0101]

[0102] In formula (10), y (n) (f k ) represents the initial frequency domain signal, represents the frequency domain signal after correction processing, X(f k ) represents the frequency domain signal vector of the kth frequency point corresponding to the M array elements.

[0103] The corrected frequency domain signal of the nth beam is subjected to inverse discrete Fourier transform to obtain the time domain signal of each satellite [y (1) (t)y (2) (t)...y (N) (t)].

[0104] In summary, the method provided in the embodiment of the present application overcomes the influence of the digital multi-beam array antenna on the carrier phase when applied in the related technology, compensates for the carrier phase error caused by the antenna array, RF channel, beamforming algorithm and other links, and ensures that the receiver can be used for precise positioning, measurement and other applications.

[0105] Specifically, the amplitude and phase transmission characteristics of the antenna pattern corresponding to the space, as well as the amplitude and phase characteristics of each RF channel and the channel frequency response characteristics, are used to calculate the amplitude and phase characteristic transfer function of each array element channel corresponding to the spatial angle, thereby establishing the array channel relative error model corresponding to the spatial domain. Finally, the digital beamformer of each satellite signal with different arrival angles is used to estimate the carrier phase correction value, and the data is corrected for amplitude and phase errors in the digital frequency domain. Through the compensation of the relative errors of the array and channels and the digital multi-beam anti-interference algorithm, a real-time high-precision anti-interference algorithm is realized.

[0106] Figure 4 for Figure 1 The schematic diagram of the system performing space-frequency anti-interference is shown in FIG. Figure 4 As shown, taking the processing of the nth beam as an example, the processing of the nth beam includes two parts, one is to perform anti-interference processing, and the other is to perform signal correction. When performing anti-interference processing, unlike the related art, the weight vector used for weighted calculation is determined according to the error transfer function corresponding to each of the M array elements to improve the accuracy of the weighted result. When performing signal correction processing, unlike the related art, the frequency domain signal corresponding to each frequency point is first processed using the carrier phase correction value, and then the conventional IDFT processing is performed.

[0107] Figure 4 The processing diagram shown provides a processing flow of frequency domain signal correction, in which the error transfer function of each array element is first determined, and the correction value of the transfer function is obtained using the error transfer function and the weight vector, and then the frequency domain signal is corrected using the correction value.

[0108] It can be seen from the above that the method provided in the embodiment of the present application proposes a digital multi-beam array antenna anti-interference scheme with carrier phase compensation for a broadband digital multi-beam former, thereby achieving the purpose of high-precision anti-interference.

[0109] An embodiment of the present application provides a storage medium, in which a computer program is stored, wherein the computer program is configured to execute any of the methods described above when running.

[0110] An embodiment of the present application provides a signal processing device in a space-frequency anti-interference system, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute any of the methods described above.

[0111] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A signal processing method in a space-frequency anti-interference system, It is characterized in that include: Obtain the frequency domain signal of the nth beam at K frequency points; Correct the frequency domain signal of each frequency point according to the carrier phase correction value corresponding to each frequency point to obtain K corrected frequency domain signals, wherein the carrier phase correction value is determined according to the error transfer function corresponding to each array element in the antenna array at each frequency point; Using the corrected K frequency domain signals, a time domain signal of the nth beam is generated; Wherein, n=1,2,3,……,N, N and K are both integers greater than or equal to 2; The carrier phase correction value of the kth frequency point is obtained by: Obtaining error transfer functions corresponding to the kth frequency point of the M array elements in the antenna array; and obtaining the weight corresponding to each array element at the kth frequency point from the weight vectors corresponding to the M array elements; Using the error transfer function and weight corresponding to each array element, weighted calculation is performed to obtain the carrier phase correction value corresponding to the kth frequency point; Wherein, k=1,2,3,……,K; m=1,2,3,……,M, M is an integer greater than or equal to 2; The error transfer function corresponding to the m-th array element is determined according to the far-field phase direction function corresponding to the m-th array element and / or the error function of the radio frequency channel corresponding to the m-th array element.

2. The method according to claim 1, It is characterized in that The far-field phase direction function corresponding to the m-th array element is determined according to at least one of the following parameters, including: The phase center offset of the mth array element; The elevation and azimuth angles of the mth element in the antenna array; The three-dimensional coordinates of the mth element on the reflection plane of the antenna array.

3. The method according to claim 2, It is characterized in that Each beam has its own corresponding far-field phase direction function of the mth array element; The far-field phase direction function corresponding to the nth beam at the mth array element is determined according to the elevation angle and azimuth angle used by the mth array element in the antenna array to receive the nth beam.

4. The method according to claim 3, It is characterized in that The expression of the far-field phase direction function of the nth beam corresponding to the mth array element is as follows: Among them, ψ m is the phase center offset of the mth array element, (x m ,y m ,z m ) represents the three-dimensional coordinate of the mth element on the reflection plane of the antenna array, θ n and They represent the elevation angle and azimuth angle used by the mth element in the antenna array to receive the nth beam, b is the wave constant, and ξ is the measurement noise.

5. The method according to claim 1, It is characterized in that The error function of the radio frequency channel corresponding to the mth array element is determined according to the amplitude error and / or phase error generated when the signal at the kth frequency point is transmitted.

6. The method according to claim 1, It is characterized in that The weight vectors corresponding to the M array elements are determined according to the error transfer functions of the M array elements.

7. The method according to claim 6, It is characterized in that Each beam has its own corresponding weight vector; wherein the weight vector of the nth beam is determined according to the space-frequency two-dimensional steering vector of the nth beam at the kth frequency point.

8. The method according to claim 7, It is characterized in that The weight vector of each beam is determined by: For the beams of N visible satellites, a set of constraint equations corresponding to each beam at the kth frequency point is established; Solve N sets of constraint equations to obtain N sets of weight vectors; Each set of constraint equations includes a first constraint equation and a second constraint equation, wherein: The first constraint equation is that the minimum value of the covariance matrix of the nth beam is equal to the value determined by the covariance matrix of the received signal at the kth frequency point and the weight vector of the nth beam at the kth frequency point; The second constraint equation is that the value determined by the error function matrix of the mth array element, the space-frequency two-dimensional steering vector of the nth beam at the kth frequency point and the weight vector of the nth beam at the kth frequency point is equal to 1.

9. The method according to claim 1, It is characterized in that The method of performing weighted calculation using the error transfer function and weight corresponding to each array element to obtain the carrier phase correction value corresponding to the kth frequency point includes: Calculate the product of the value of the error transfer function of each array element and the weight of the respective error transfer function to obtain a calculation result; The sum of the calculation results of the M array elements is calculated as the carrier phase correction value of the nth beam at the kth frequency point.

10. A storage medium, It is characterized in that The storage medium stores a computer program, wherein the computer program is configured to execute the method according to any one of claims 1 to 9 when executed.

11. A signal processing device in a space-frequency anti-interference system, comprising a memory and a processor, It is characterized in that A computer program is stored in the memory, and the processor is configured to run the computer program to perform the method according to any one of claims 1 to 9.

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