A broadband receive DBF system external radiation correction method and device

Abstract

The application discloses a wideband receiving DBF system external radiation correction method and device, belongs to the technical field of digital beam forming, aiming at the problem that the existing wideband DBF system external radiation correction only adopts normal direction correction data, and the problems of insufficient full-space correction accuracy and large correction deviation when a large-angle beam points, provides a sub-space external radiation correction method based on beam pointing, completes the receiving radio frequency channel internal correction and switches the external correction mode, determines the corresponding correction point according to the working space range and the number of beams, collects the synchronous data point by point to calculate the initial correction coefficient, solves the final correction coefficient in combination with the inherent phase difference of the beam pointing, and obtains the external correction coefficient of the full working space after traversing all the beam pointing, so that the full-space correction accuracy is improved, the beam pointing accuracy, the main lobe gain and the side lobe level are improved, and the method has obvious engineering application value.

Description

Technical Field

[0001] This invention relates to the field of digital beamforming technology, and more specifically to an external radiation correction method and apparatus for a broadband receiving DBF system. Background Technology

[0002] Wideband digital beamforming (DBF) offers a range of advantages, including wide operating bandwidth, simultaneous independent multi-beam operation, and flexible beamforming. Therefore, receiving systems based on DBF have wide applications in numerous fields such as communications, radar, and electronic warfare. However, inconsistencies between RF channels and array antenna elements can severely affect the pointing and shape characteristics of the DBF received beam. Therefore, amplitude and phase consistency correction is required for both the RF channels and the array antenna elements.

[0003] Currently, array antenna calibration typically involves placing a radiation source in the far field of the antenna to be calibrated, then collecting amplitude and phase data in the normal direction of each element to calculate the compensation value during digital beamforming. However, in practical broadband DBF system applications, due to factors such as mutual coupling, manufacturing tolerances, installation errors, and radomes, the array antenna elements exhibit differences in azimuth amplitude and phase response. Figure 2 As shown. However, existing broadband receiver DBF system external radiation correction methods do not consider the inconsistency of different incident directions. When forming digital beam weighting coefficients, only the correction data of the normal direction is used, which leads to the problem that the correction coefficients deviate greatly when deviating from the normal, especially at large angles, and thus cannot form an accurate beam.

[0004] To ensure the accuracy of multi-beam formation in the entire airspace of a broadband receiving DBF system, a high-precision external radiation correction method that can adapt to different beam directions and cover the entire working airspace is needed. Summary of the Invention

[0005] In view of the above problems, the present invention provides an external radiation correction method and apparatus for a broadband receiving DBF system, which can solve the problems of existing broadband receiving DBF systems using only normal direction correction data for external radiation correction, insufficient full-space correction accuracy, large correction coefficient deviation and low beamforming accuracy when pointing at large angles. It can achieve high-precision external radiation correction for the entire working space of the broadband receiving DBF system and improve the accuracy and stability of multi-beamforming.

[0006] In a first aspect, the present invention provides an external radiation correction method for a broadband receiving DBF system, applied to a broadband digital beamforming (DBF) system including an array antenna, a multi-channel receiving radio frequency link, and a digital processing unit. The method includes the following steps: S1. After completing the internal calibration of each receiving radio frequency channel of the system, switch the system to external radiation calibration mode. S2. Based on the system's working airspace range and the preset number of simultaneously received beams, determine the far-field external radiation correction points corresponding to the direction of each beam; S3. For a single correction point, control the correction signal radiation source to transmit the correction signal along the corresponding beam direction, collect the synchronous sampling data of each receiving channel of the system, and calculate the initial correction coefficient corresponding to the current beam direction. S4. Based on the incident angle of the current beam direction and the array antenna element arrangement parameters, calculate the inherent phase difference between each receiving channel and the preset reference channel. S5. Based on the initial correction coefficient and the inherent phase difference, calculate and store the final correction coefficient for the current beam pointing. S6. Sequentially switch all far-field external radiation correction points, repeat S3 to S5, and after traversing all beam pointing directions, obtain the external correction coefficients corresponding to all beams in the entire working space.

[0007] In some embodiments, in step S2, the incident angles of all far-field external radiation correction points uniformly cover the entire working space of the system, and the incident angle of each correction point is consistent with the center pointing angle of the corresponding beam.

[0008] In some embodiments, in step S3, the correction signal radiation source sequentially transmits multiple sub-frequency correction signals covering the entire operating bandwidth of the system at preset frequency intervals. After traversing all sub-frequency points, the initial correction coefficients corresponding to each sub-frequency point are obtained by pointing the current beam to each sub-frequency point.

[0009] In some embodiments, step S3 includes: performing a discrete Fourier transform on the synchronous sampling data of each receiving channel to obtain IQ complex data of the corresponding correction sub-frequency point of each channel; and calculating the amplitude value and phase value of the corresponding sub-frequency point of each channel based on the IQ complex data.

[0010] In some embodiments, step S3 further includes: selecting one of the receiving channels as a reference channel; and calculating the initial correction coefficient of each channel relative to the reference channel based on the ratio of the amplitude value and phase value of the remaining channels to the reference channel.

[0011] In some embodiments, in step S4, the inherent phase difference is the phase difference between the signal incident on each receiving channel and the reference channel due to the path difference under the correction signal of the current beam pointing, which is calculated based on the incident angle, the array element spacing, the correction signal frequency and the speed of light.

[0012] In some embodiments, the array antenna is a uniform linear array with a fixed spacing between adjacent array elements. The corresponding inherent phase difference is calculated based on the spacing difference between the array elements corresponding to each channel and the array elements corresponding to the reference channel.

[0013] In some embodiments, in step S5, the final correction coefficient for the current beam pointing is calculated by subtracting the corresponding inherent phase difference from the initial correction coefficient. The final correction coefficient is an IQ complex coefficient that includes amplitude compensation and phase compensation.

[0014] In some embodiments, in step S6, the switching of the far-field external radiation correction point is controlled by adjusting the incident angle of the far-field correction signal radiation source or adjusting the turntable angle of the carrier array antenna.

[0015] In some embodiments, in step S6, the external correction coefficients corresponding to all the traversed beams are integrated and stored as an external correction file. The external correction file is used in conjunction with the system correction table and beamforming weight coefficients for weighted calculation of the broadband DBF receiving beam.

[0016] In a second aspect, embodiments of the present invention provide an external radiation correction device for a broadband receiving DBF system, applied to a broadband digital beamforming (DBF) system including an array antenna, a multi-channel receiving radio frequency link, and a digital processing unit, the device comprising: The switching module is used to switch the system to external radiation correction mode after completing the internal correction of each receiving radio frequency channel of the system. The determination module is used to determine the far-field external radiation correction points corresponding to the direction of each beam, based on the system's working airspace range and the preset number of simultaneously received beams. The first calculation module is used to collect synchronous sampling data from each receiving channel of the system after controlling the correction signal radiation source to transmit the correction signal along the corresponding beam direction for a single correction point, and calculate the initial correction coefficient corresponding to the current beam direction. The second calculation module is used to calculate the inherent phase difference between each receiving channel and the preset reference channel based on the incident angle of the current beam pointing and the array element arrangement parameters of the array antenna. The third calculation module is used to calculate and store the final correction coefficient of the current beam pointing based on the initial correction coefficient and the inherent phase difference. The traversal module is used to sequentially switch all far-field external radiation correction points, repeatedly call the first calculation module, the second calculation module, and the third calculation module, and after traversing all beam pointing, obtain the external correction coefficients corresponding to all beams in the entire working space.

[0017] The present invention provides an external radiation correction method, apparatus, device, and medium for a broadband receiving DBF system. Compared with the prior art, the present invention has the following advantages: This invention employs a beam pointing-based spatial domain radiation correction scheme. It sets correction points and calculates unique correction coefficients for each beam pointing direction, replacing the traditional approach of using uniform correction coefficients along the normal direction. This fully considers the amplitude and phase response differences of the array antenna at different incident angles, fundamentally solving the problem of large correction coefficient deviations at large beam pointing angles. It achieves high-precision correction across the entire working spatial domain of the broadband DBF system. By using a multi-sub-frequency traversal correction method, it covers the entire working bandwidth of the system, calculating correction coefficients for each sub-frequency point separately. This adapts to the wideband operating characteristics of broadband systems, effectively improving the amplitude and phase correction accuracy across all frequencies within the band and avoiding beam distortion problems caused by amplitude and phase inconsistencies at different frequencies in broadband systems.

[0018] This invention deducts the inherent path difference and phase difference of the corresponding beam pointing of the array antenna when calculating the final correction coefficients, ensuring that the correction coefficients are only used to compensate for the amplitude and phase inconsistency deviation between the array and the channel, avoiding interference from the inherent phase difference on the correction coefficients, and improving the accuracy of beamforming. By performing beam-by-beam traversal correction, a dedicated correction coefficient table for each beam in the entire spatial domain is generated. When used in conjunction with the system's correction table and beam weight coefficients, it can effectively improve the pointing accuracy, main lobe gain, sidelobe level, and beam shape of the received beam, significantly improving the direction finding accuracy, receiving performance, and anti-interference capability of the broadband multi-beam DBF system, and has significant engineering application value.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0020] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0021] Figure 1 This diagram illustrates an exemplary external radiation correction method for a broadband receiving DBF system according to an embodiment of the present invention. Figure 2 This diagram illustrates the phase fluctuation of each element of an array antenna at different incident angles in an exemplary background art according to an embodiment of the present invention. Figure 3 A flowchart illustrating an exemplary external radiation correction method for a broadband receiving DBF system according to an embodiment of the present invention is shown. Figure 4 A schematic diagram illustrating an exemplary distribution of far-field external radiation correction points based on beam pointing, as proposed in one embodiment of the present invention, is shown. Figure 5This diagram illustrates an exemplary principle of the path difference and inherent phase difference between array elements when a correction signal is incident, according to an embodiment of the present invention. Figure 6 The diagram illustrates a system block diagram of an exemplary embodiment of a 16-channel, 16-beam broadband receiver (DBF) device proposed in one embodiment of the present invention. Figure 7 A schematic diagram comparing the beam pattern of an exemplary method of the present invention with that of a traditional normal direction correction method is shown in one embodiment of the present invention. Figure 8 The diagram shows a structural block diagram of an external radiation correction device for a broadband receiving DBF system according to an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are only for explaining this invention and are not intended to limit this invention.

[0023] This embodiment uses a 16-channel, 16-beam broadband receiver DBF system as the implementation body. The system composition is as follows: Figure 6 As shown, the system includes a digital processing unit, M array receiving channels, a calibration source, a calibration coupling network, and an array antenna. The digital processing unit integrates calibration signal processing, calibration table generation, synchronous sampling control, and system control functions. Each of the M array receiving channels corresponds one-to-one with an array antenna element. Each channel includes a low-noise amplifier, a frequency conversion module, a filter circuit, and an analog-to-digital converter to amplify, convert, filter, and digitally sample the received signal. The calibration source receives control commands from the digital processing unit and generates a single-frequency calibration signal for the corresponding frequency point. The calibration coupling network couples the signal from the calibration source to each receiving channel, achieving in-channel calibration. The array antennas are uniformly and linearly arranged to receive external input RF signals.

[0024] In this embodiment, the test environment involves placing a broadband receiving DBF system in an anechoic chamber turntable. External radiation correction for each beam direction is performed by controlling the radiation source and the turntable angle. After completion, an external correction coefficient table for each working beam is generated. The external correction coefficient table, internal correction table, and weighting coefficients are used in conjunction with the weighting coefficients of the received beam to obtain the desired accurate beam.

[0025] See Figure 1 The implementation process of this embodiment is as follows: S1. After completing the internal calibration of each receiving radio frequency channel of the system, switch the system to external radiation calibration mode. In this embodiment, the internal calibration process of the receiving RF channel is first executed: the digital processing unit sends a control command to the calibration source to control the calibration source to generate a calibration signal covering the entire operating bandwidth. The calibration signal is input to the 16 array receiving channels in equal amplitude and phase through the calibration coupling network. The digital processing unit synchronously samples the output signals of the 16 channels, calculates the amplitude and phase response of each channel within the entire operating bandwidth, and, using the first channel as a reference, solves for the internal calibration coefficient table of each channel and stores it in the non-volatile memory of the digital processing unit, eliminating the amplitude and phase inconsistencies of each receiving RF channel. After the internal calibration is completed, the digital processing unit closes the signal path of the calibration coupling network through the system control logic, switches to the array antenna receiving path, and simultaneously switches the operating mode of the digital processing unit from the internal calibration calculation mode to the external calibration sampling and calculation mode, completing the switch of the external radiation calibration mode.

[0026] S2. Based on the system's working airspace range and the preset number of simultaneously received beams, determine the far-field external radiation correction points corresponding to the direction of each beam; In this embodiment, the system presets the number of simultaneously received beams to be M, with a working spatial range of -45° to +45°. Based on this, M far-field external radiation correction points are determined. The incident angles of the M correction points are uniformly distributed within the range of -45° to +45°, and the incident angle of each correction point corresponds one-to-one with the center pointing angle of the M received beams. That is, the center pointing angle of each beam corresponds to a dedicated correction point, ensuring that the correction coefficient of each beam is perfectly adapted to the spatial amplitude and phase characteristics of its pointing direction.

[0027] S3. For a single correction point, control the correction signal radiation source to transmit the correction signal along the corresponding beam direction, collect the synchronous sampling data of each receiving channel of the system, and calculate the initial correction coefficient corresponding to the current beam direction. In this embodiment, a correction point with an incident angle of 30° can be selected. The digital processing unit sends a control command to the turntable, controlling the turntable to rotate to a position where the angle between the array antenna normal and the incident direction of the correction signal radiation source is 30°, ensuring that the incident angle of the correction signal is perfectly aligned with the center pointing angle of the corresponding beam. Subsequently, the digital processing unit sends a control command to the correction signal radiation source, controlling the radiation source to sequentially transmit single-frequency correction sub-frequency signals covering the entire operating bandwidth at frequency intervals.

[0028] For each correction sub-frequency point, the digital processing unit synchronously samples the intermediate frequency output signal of the M array receiving channels, counting the number of sampling points per frequency point; it then performs a Fast Fourier Transform on the sampled data of each channel, counting the number of sampling points, to obtain the IQ complex data corresponding to the correction sub-frequency point for each channel. The IQ complex data of the m-th channel is represented as follows:

[0029] In the formula, Let be the amplitude of the in-phase component of the m-th channel I. Let m be the amplitude of the Q-path quadrature component of the m-th channel, where m is the channel number and takes values ​​of 1, 2, ..., M.

[0030] Based on the aforementioned IQ complex data, the amplitude value of the m-th channel corresponding to the sub-frequency point is calculated. and phase value The calculation formula is:

[0031]

[0032] In this embodiment, the first channel is selected as the reference channel. Based on the amplitude and phase data of the other channels and the reference channel, the initial correction coefficient of the m-th channel relative to the reference channel is calculated. The calculation formula is:

[0033] In the formula, P1 is the IQ complex data of the reference channel, A1, These are the amplitude and phase values ​​of the reference channel, respectively.

[0034] After traversing all correction sub-frequency points, the initial correction coefficient matrix X( ) is obtained for each sub-frequency point within the full working bandwidth corresponding to the 30° beam pointing. , … ).

[0035] S4. Based on the incident angle of the current beam direction and the array antenna element arrangement parameters, calculate the inherent phase difference between each receiving channel and the preset reference channel. In this embodiment, the inherent phase difference is the inherent phase shift introduced by the path difference of the signal reaching different array elements when the correction signal can be incident from a 30° direction due to the spatial position difference of each array element. This phase shift is the inherent guiding phase of the array beam formation, not the amplitude-phase inconsistency deviation between the array elements and the channel, and needs to be deducted from the correction coefficient.

[0036] In this embodiment, the array antenna is a uniform linear array, and the spacing between adjacent array elements is a fixed value d. The difference in spacing between the array element corresponding to the m-th channel and the array element corresponding to the reference channel (e.g., the 1st channel) is... Given a signal wavelength λ = c / f, a correction signal frequency f, and a light speed c, the inherent phase difference between the m-th channel and the reference channel is... The calculation formula is:

[0037] By traversing all correction sub-frequency points, the inherent phase difference matrix corresponding to each sub-frequency point under 30° beam pointing is obtained. ( , … ).

[0038] S5. Based on the initial correction coefficient and the inherent phase difference, calculate and store the final correction coefficient for the current beam pointing. In this embodiment, the initial correction coefficients are subtracted from the corresponding inherent phase difference to obtain the final correction coefficients used only to compensate for the amplitude-phase inconsistency between the array elements and the channels. The final correction coefficients for the sub-frequency point corresponding to the m-th channel are then used. The calculation formula is:

[0039] To adapt to the computational requirements of digital signal processing, the above complex coefficients are expanded into real and imaginary IQ coefficients: Real part:

[0040] Virtual part:

[0041] By traversing all correction sub-frequency points, the final correction coefficient matrix Z( ) of each sub-frequency point of the M channels under 30° beam pointing is obtained. , … The data is stored as a correction sub-table for the current beam and written into the memory of the digital processing unit to complete the external radiation correction of the current beam.

[0042] S6. Sequentially switch all far-field external radiation correction points, repeat S3 to S5, and after traversing all beam pointing directions, obtain the external correction coefficients corresponding to all beams in the entire working space.

[0043] In this embodiment, the turntable is controlled by the digital processing unit to rotate sequentially to the remaining correction points. The incident angle of each correction point is perfectly matched with the center pointing angle of the corresponding beam. The complete correction process from S3 to S5 is repeated at each point to obtain the correction sub-table corresponding to each beam. The correction sub-tables of the beams are integrated into the system's full-space-domain out-of-space correction coefficient file and stored in the system's non-volatile memory.

[0044] When the system is working normally, the external calibration file is used in conjunction with the channel calibration table and beamforming weighting coefficients: for the received data of each beam, the amplitude and phase deviation of the channel link is first compensated by the internal calibration table, then the amplitude and phase inconsistency of the array spatial domain is compensated by the external calibration coefficients pointing to the corresponding beam, and finally the weighted sum is completed by the beam weighting coefficients to form a high-precision receiving beam.

[0045] The verification of the correction effect in this embodiment is as follows: Figure 7 As shown, the blue curve represents the beam pattern formed at 30° using the traditional normal direction correction coefficient, while the red curve represents the beam pattern at 30° obtained using the method of this embodiment. The comparison demonstrates that, by employing the method of this invention, the beam pointing accuracy is significantly improved, the main lobe gain is increased, the sidelobe level is greatly reduced, and the beam shape remains distortion-free, resulting in an accurate receiving beam that meets design expectations.

[0046] See Figure 3 An exemplary implementation process of this application is as follows: Step S1: The uniform linear array broadband DBF system first performs internal calibration in the receiving RF channel, and then enters the external radiation calibration mode; Step S2: Based on the system's operating airspace range and the number of beams N, such as Figure 4 The diagram shows the far-field external radiation correction points for N beams, with the angle between the correction signal radiation source position and the normal direction of the broadband array antenna element being [value missing]. , to ; Step S3: Correct the signal radiation source to be located at the beam pointing θ, and set the radiation source emission frequency to θ. The correction signal is obtained by the receiving and processing system sampling the synchronization signals of M channels and performing discrete Fourier transform to obtain the IQ data of the M channels at the correction frequency. After calculation, the amplitude and phase data of each channel are obtained. By selecting the first channel to be received as a reference, the amplitude and phase data of all other channels can be calculated. Initial correction coefficient X (frequency point) ); Channel m correction data and amplitude and phase values:

[0047]

[0048] Correction data for channel m relative to reference channel 1:

[0049] To improve the correction accuracy of broadband systems, the radiation source sequentially emits multiple sub-frequency points at small intervals, and after traversal, forms the initial external radiation correction coefficient X( ) for the current beam. , … ); Step S4: The correction signal is incident from the θ direction, such as... Figure 5 As shown, the spacing between the array elements is d. The inherent phase difference between channel m and channel 1 at each corrector frequency point can be calculated as follows: ( , … ); The inherent phase difference between channel m and channel 1, where, , ;

[0050] Step S5: The correction coefficient Z( ) for each sub-frequency point of each channel of the current beam can be obtained by calculating the initial correction coefficient of the external radiation and the inherent phase difference. , … The external radiation correction of the current beam is completed, and the IQ correction coefficients are generated and stored. Correction coefficient Z( , … The real and imaginary parts of )

[0051]

[0052] Step S6: Change the far-field external radiation correction point and repeat steps 2 to 5. After traversing, obtain the external correction coefficients of N beams, store them as an external correction file, and complete the external radiation correction work of this system.

[0053] Please see Figure 8 , Figure 8 This invention provides a structural block diagram of an external radiation correction device 300 for a broadband receiving DBF system. Applied to a broadband digital beamforming (DBF) system including an array antenna, a multi-channel receiving RF link, and a digital processing unit, the device includes: a switching module 310, a confirmation module 320, a first calculation module 330, a second calculation module 340, a third calculation module 350, and a traversal module 360, wherein: The switching module 310 is used to couple and sample the synthesized echo signal to obtain the sampled signal of the synthesized signal. The determination module 320 is used to perform envelope detection processing on the sampled signal, extract the time domain envelope of the synthesized echo signal, and generate an analog video signal carrying amplitude information; The first calculation module 330 is used to perform video AD acquisition and quantization on the analog video signal and convert it into a digital envelope signal; The second calculation module 340 is used to perform envelope feature analysis on the digital envelope signal and calculate the peak-to-average power ratio of the synthesized echo signal corresponding to the phase combination of the current analog signals. The third calculation module 350 is used to calculate and store the final correction coefficient of the current beam pointing based on the initial correction coefficient and the inherent phase difference. The traversal module 360 ​​is used to sequentially switch all far-field external radiation correction points. After repeatedly executing each calculation module to traverse all beam pointing, the external correction coefficients corresponding to all beams in the entire working space are obtained.

[0054] It should be noted that the device embodiments in this invention correspond to the aforementioned method embodiments. The specific principles in the device embodiments can be found in the content of the aforementioned method embodiments, and will not be repeated here.

[0055] In the several embodiments provided in this example, the coupling between modules can be electrical, mechanical, or other forms of coupling.

[0056] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An external radiation correction method for a broadband receiving DBF system, applied to a broadband digital beamforming (DBF) system including an array antenna, a multi-channel receiving RF link, and a digital processing unit, characterized in that, include: S1. After completing the internal calibration of each receiving radio frequency channel of the system, switch the system to the external radiation calibration mode. S2. Based on the system's working airspace range and the preset number of simultaneously received beams, determine the far-field external radiation correction points corresponding to the direction of each beam; S3. For a single correction point, control the correction signal radiation source to transmit the correction signal along the corresponding beam direction, collect the synchronous sampling data of each receiving channel of the system, and calculate the initial correction coefficient corresponding to the current beam direction. S4. Based on the incident angle of the current beam direction and the array antenna element arrangement parameters, calculate the inherent phase difference between each receiving channel and the preset reference channel. S5. Based on the initial correction coefficient and the inherent phase difference, calculate and store the final correction coefficient for the current beam pointing. S6. Sequentially switch all far-field external radiation correction points, repeat S3 to S5, and after traversing all beam pointing directions, obtain the external correction coefficients corresponding to all beams in the entire working space.

2. The external radiation correction method for a broadband receiving DBF system according to claim 1, characterized in that, The incident angles of all far-field external radiation correction points uniformly cover the entire working space of the system, and the incident angle of each correction point is consistent with the center pointing angle of the corresponding beam.

3. The external radiation correction method for a broadband receiving DBF system according to claim 1, characterized in that, The correction signal radiation source sequentially transmits multiple sub-frequency correction signals covering the entire operating bandwidth of the system at preset frequency intervals. After traversing all sub-frequency points, the initial correction coefficients corresponding to each sub-frequency point pointed to by the current beam are obtained.

4. The external radiation correction method for a broadband receiving DBF system according to claim 3, characterized in that, Step S3 includes: The synchronous sampling data of each receiving channel is subjected to discrete Fourier transform to obtain the IQ complex data of the corresponding correction sub-frequency point of each channel; The amplitude and phase values ​​of each channel's corresponding sub-frequency point are calculated based on the IQ complex data.

5. The external radiation correction method for a broadband receiving DBF system according to claim 4, characterized in that, Step S3 also includes: Select one of the receiving channels as the reference channel; Based on the ratios of the amplitude and phase values ​​of the remaining channels to the reference channel, the initial correction coefficients of each channel relative to the reference channel are calculated.

6. The external radiation correction method for a broadband receiving DBF system according to claim 1, characterized in that, The inherent phase difference is the phase difference introduced by the path difference between the signal incident on each receiving channel and the reference channel under the current beam pointing correction signal, and is calculated based on the incident angle, array element spacing, correction signal frequency and light speed.

7. The external radiation correction method for a broadband receiving DBF system according to claim 6, characterized in that, The array antenna is a uniform linear array with a fixed spacing between adjacent array elements. The corresponding inherent phase difference is calculated based on the spacing difference between the corresponding array element of each channel and the corresponding array element of the reference channel.

8. The external radiation correction method for a broadband receiving DBF system according to claim 1, characterized in that, In step S5, the corresponding inherent phase difference is subtracted from the initial correction coefficient to calculate the final correction coefficient for the current beam pointing. The final correction coefficient is an IQ complex coefficient that includes amplitude compensation and phase compensation.

9. The external radiation correction method for a broadband receiving DBF system according to claim 1, characterized in that, In step S6, the switching of the far-field external radiation correction point is controlled by adjusting the incident angle of the far-field correction signal radiation source or adjusting the turntable angle of the carrier array antenna.

10. An external radiation correction device for a broadband receiving DBF system, characterized in that, An apparatus for use in a broadband digital beamforming (DBF) system comprising an array antenna, a multi-channel receive RF link, and a digital processing unit, the apparatus comprising: The switching module is used to couple and sample the synthesized echo signal to obtain the sampled signal of the synthesized signal; The determination module is used to perform envelope detection processing on the sampled signal, extract the time-domain envelope of the synthesized echo signal, and generate an analog video signal carrying amplitude information; The first calculation module is used to perform video AD acquisition and quantization on the analog video signal and convert it into a digital envelope signal; The second calculation module is used to perform envelope feature analysis on the digital envelope signal and calculate the peak-to-average power ratio of the synthesized echo signal corresponding to the phase combination of each analog signal. The third calculation module is used to calculate and store the final correction coefficient of the current beam pointing based on the initial correction coefficient and the inherent phase difference. The traversal module is used to sequentially switch all far-field external radiation correction points, and after repeatedly executing each calculation module to traverse all beam pointing, the external correction coefficients corresponding to all beams in the entire working space are obtained.

Images