A target generation method for full-digital passive array beam testing

Abstract

The application discloses a target generating method for full-digital passive array beam testing, and steps are as follows: an array control computer reads the pointing value, working frequency point and other parameters of an analog target through a display control interface, and calculates the required in-array phase difference of the analog target; the array computer forms a control instruction according to the analog target parameters and the in-array phase difference parameters, and sends the control instruction to a system control computer; after the system control computer receives the instruction, the control instruction is sent to an equal-length feed line feeding input component and a signal generating module, and a signal enable timing is generated according to the control instruction; after the equal-length feed line feeding input component collects the signal, phase modulation processing is carried out by using the in-array phase compensation value, so that the analog target data of a specific pointing direction is formed; under the control of the packaging timing, the equal-length feed line feeding input component sends the sampling data of all units to a DBF module, and beam synthesis processing is carried out. The application realizes the testing of full-digital array beam arrangement and scanning characteristics.

Description

Technical Field

[0001] This invention relates to target simulation methods, and in particular to a target generation method for all-digital passive array beam testing. Background Technology

[0002] Passive array antennas are an important branch of phased array antennas, used in various communication reconnaissance, electronic reconnaissance, and non-cooperative detection. Their beam performance significantly impacts system sensitivity, angle measurement accuracy, and resolution. Generally, after antenna production, near-field testing in an anechoic chamber is conducted to verify beam scanning characteristics, sidelobe characteristics, and channel amplitude and phase compensation. Once the antenna's state is solidified, it is used in the field with the system. However, during field use, changes in ambient temperature alter the performance of components within the channels, leading to decreased amplitude and phase consistency across channels. Therefore, testing the antenna's beam performance is necessary. A common practice is to set up a point source in the far field and test the antenna's beam at different scanning angles by rotating the antenna, thereby determining its beam performance. However, this method has several drawbacks: First, passive array antennas are generally large, with long far-field distances, requiring specific site conditions; second, the antenna needs a precise servo control mechanism to achieve array pointing control, but large passive arrays are typically fixed and lack precise servo control mechanisms; third, beam testing in the far field is affected by multipath propagation and other environmental factors, hindering accurate evaluation of array beam performance. A search of existing patents reveals few methods for field testing of array antenna beams. Patent number 202011334764.6 provides a method for testing passive array beams, but this method is only applicable to anechoic chamber environments and does not address the challenges of field testing. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a target generation method for testing all-digital passive array beams, enabling the testing of the beam arrangement and scanning characteristics of all-digital arrays. This greatly improves the efficiency of field testing, eliminates the need for far-field conditions, and isolates environmental factors in the field, effectively verifying the beam scanning performance of the array.

[0004] The objective of this invention is achieved through the following technical solutions.

[0005] A target generation method for all-digital passive array beam testing uses an in-array monitoring signal for simulation. This signal is fed into the receiving component using an equal-length feeder. To simulate targets pointing in different directions, the in-array phase difference is used to simulate the spatial phase difference. The steps are as follows:

[0006] 1) The array control computer reads parameters such as the pointing value and operating frequency of the simulated target through the display and control interface, and calculates the required intra-array phase difference for the simulated target;

[0007] 2) The array computer calculates the target parameters and the phase difference parameters within the array based on the simulated parameters. The control command is generated and sent to the system control computer. The simulated target parameters include f0 as the center frequency, PW as the pulse width, PRI as the repetition period, and BW as the signal bandwidth.

[0008] 3) After receiving the instruction, the system control computer sends control instructions to the equal-length feeder input receiving component and the signal generation module. At the same time, it generates a signal enable timing according to the control instructions, where t1 is the signal enable advance time. The control signal generation module generates a simulated target signal, where t2 is the simulated target pulse width. It generates a sampling timing and controls the equal-length feeder input receiving component to perform signal acquisition. The sampling gate length is the same as the simulated target pulse width.

[0009] 4) After the signal is collected by the receiving component fed into the equal-length feeder, it is digitally orthogonally down-converted and phase-modulated using the phase compensation value in the array to form analog target data with a specific direction.

[0010] 5) Under the control of the packing timing, the equal-length feeder input receiving component sends the sampled data of all units to the DBF module for beamforming processing, t3 packing preparation time.

[0011] Step 1) calculates the intra-array phase difference required for the simulated target:

[0012]

[0013] d: the intra-array phase difference required to simulate the target; d: the array cell spacing. Simulated target pointing

[0014] Then, the k-th unit has k=1,…,N, where N is the total number of antenna elements.

[0015] Step 4) specifically involves:

[0016] 4.1) Digital quadrature downconversion processing

[0017] For the k-th unit, the received signal recorded during the n-th sampling time is:

[0018]

[0019] Where a(n) is the signal amplitude; The angular frequency corresponding to the intermediate frequency of the signal; This is the phase difference between the analog signal and the local oscillator signal; This is the initial phase of the analog signal;

[0020] Since the simulated signal uses a conventional pulse signal, the signal amplitude remains constant during the pulse duration, and the signal exhibits time invariance, therefore a(n), , All are constants, using , , express,

[0021] Will Multiply by respectively and After filtering, we can obtain

[0022]

[0023]

[0024] 4.2) In-array phase compensation modulation processing

[0025] Based on the phase compensation value within the simulated target array For k=1, ..., N, we have:

[0026]

[0027]

[0028] in, The definition is the same as before;

[0029] 4.3) Target Data Synthesis

[0030] All targets are generated from the same simulation source. For the k-th cell, the IQ data for all targets at time n are: .

[0031] Compared to existing technologies, the advantages of this invention are as follows: This invention utilizes internal monitoring signals to simulate targets pointing in different directions, enabling the testing of the beam arrangement and scanning characteristics of a fully digital array without the need for far-field external monitoring signals. This significantly improves the efficiency of field testing. The invention is simple to implement, isolates the influence of external environmental factors on the beam scanning performance of large passive arrays, and enables multi-beam performance evaluation. It does not require far-field conditions, effectively verifying the beam scanning performance of arrays. Attached Figure Description

[0032] Figure 1 This is a schematic diagram illustrating the simulated target generation of the present invention.

[0033] Figure 2 This invention simulates the timing relationship of target generation. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0035] This invention uses an in-array monitoring signal for simulation, which is fed into the receiving component (R component) using an equal-length feeder. To simulate targets pointing in different directions, the in-array phase difference is used to simulate the spatial phase difference, as follows:

[0036] 1) The array control computer reads parameters such as the pointing value and operating frequency of the simulated target through the display and control interface, and calculates the required intra-array phase difference for the simulated target, as follows:

[0037]

[0038] d: the intra-array phase difference required to simulate the target; d: the array cell spacing. Simulated target pointing

[0039] Then, the k-th unit has k=1, ...,N, where N is the total number of antenna elements.

[0040] 2) The array computer simulates the target parameters (f0, PW, PRI, BW, ... and intra-array phase difference parameters This generates control commands which are then sent to the system control computer, where f0 is the center frequency, PW is the pulse width, PRI is the repetition period, and BW is the signal bandwidth.

[0041] 3) After receiving the instruction, the system control computer sends control instructions to the R component and the signal generation module. Simultaneously, it generates a signal enable timing based on the control instructions, where t1 is the signal enable advance time. The control signal generation module generates a simulated target signal, where t2 is the simulated target pulse width, and generates a sampling timing. The R component is then controlled to perform signal acquisition, with the sampling gate length matching the simulated target pulse width. The timing relationship is shown in the appendix. Figure 2

[0042] 4) After the R component acquires the signal, it performs digital quadrature down-conversion processing and uses the in-array phase compensation value for phase modulation processing to form analog target data with a specific direction. The method is as follows:

[0043] 4.1) Digital quadrature downconversion processing

[0044] For the k-th unit, the received signal recorded during the n-th sampling time is:

[0045]

[0046] Where a(n) is the signal amplitude; The angular frequency corresponding to the intermediate frequency of the signal; This is the phase difference between the analog signal and the local oscillator signal; This represents the initial phase of the analog signal.

[0047] Since the simulated signal uses a conventional pulse signal, the signal amplitude remains constant during the pulse duration, and the signal exhibits time invariance. Therefore, a(n), , All are constants, using , , express.

[0048] Will Multiply by respectively and After filtering, we can obtain

[0049]

[0050]

[0051] 4.2) In-array phase compensation modulation processing

[0052] Based on the phase compensation value within the simulated target array For k=1, ..., N, we have:

[0053]

[0054]

[0055] in, The definition is the same as before.

[0056] 4.3) Target Data Synthesis

[0057] All targets are generated from the same simulation source. For the k-th cell, the IQ data for all targets at time n are: .

[0058] 5) Under the control of the packaging timing, the R component samples the data from all units. Send the signal to the DBF module for beamforming processing; the timing relationship is shown in the attached figure. Figure 2 t3 packaging preparation time.

[0059] Example

[0060] The above method describes simulation for a single target. Multiple targets can also be simulated simultaneously to achieve multi-beam testing, as described below:

[0061] 1) Determine the location of multiple simulated targets. To achieve simultaneous multi-beam testing, the location is determined based on the system's multi-beam forming capability, beamwidth, and beam scanning range, as follows:

[0062] Calculate beamwidth:

[0063] Where k is the beamwidth factor, which ranges from 51 to 74. When the beam is unweighted, it is 51. Other values ​​are different depending on the weighting type. For example, when Taylor weighting is used, k can be 65. λ is the wavelength of the target signal, which is determined according to the operating frequency. N is the number of azimuth elements. d is the element spacing.

[0064] Determine the target bearing interval and starting target bearing.

[0065] Assuming the overlap factor is 1, the target spacing is one beamwidth. The initial target azimuth can be determined based on the scanning range of the test beam. , where is the minimum angle of beam coverage.

[0066] Determine the location of each target.

[0067]

[0068] Where i = 1, ..., m, m is the number of simultaneous beams, which is not greater than the maximum number of beams required by the system. Not greater than

[0069] 2) Calculate the required intra-array phase difference compensation value for each target.

[0070] According to Formula 1, the calculation is as follows: The definition of i is the same as before. For the i-th target, the required in-array phase compensation value for different array elements is: k=1, ...,N, where N is the number of units.

[0071] 3) The array computer simulates the target parameters (f0, PW, PRI, BW, ... and intra-array phase difference parameters This generates control commands which are then sent to the system control computer, where f0 is the center frequency, PW is the pulse width, PRI is the repetition period, and BW is the signal bandwidth.

[0072] 4) After receiving the instruction, the system control computer sends control instructions to the R component and the signal generation module. Simultaneously, it generates a signal enable timing based on the control instructions, where t1 is the signal enable advance time. The control signal generation module generates a simulated target signal, where t2 is the simulated target pulse width, and generates a sampling timing. The R component is then controlled to perform signal acquisition, with the sampling gate length matching the simulated target pulse width. The timing relationship is shown in the appendix. Figure 2 ;

[0073] 5) After the R component acquires the signal, it performs digital quadrature down-conversion processing and uses the in-array phase compensation value for phase modulation processing to form analog target data with a specific direction. The method is as follows:

[0074] Step 1: Digital Quadrature Down-Conversion Processing

[0075] For the k-th unit, the received signal recorded during the n-th sampling time is:

[0076]

[0077] Where a(n) is the signal amplitude; The angular frequency corresponding to the intermediate frequency of the signal; This is the phase difference between the analog signal and the local oscillator signal; This represents the initial phase of the analog signal.

[0078] Since analog signals use conventional pulse signals, the signal amplitude remains constant during the pulse duration, and the signal exhibits time invariance. Therefore, a(n), , All are constants, using , , express.

[0079] Will Multiply by respectively and After filtering, we can obtain:

[0080]

[0081]

[0082] Step 2: In-array phase compensation modulation processing

[0083] Based on the phase compensation value within the i-th simulated target array ,have:

[0084]

[0085]

[0086] in, The definition is the same as before.

[0087] Step 3: Target Data Synthesis

[0088] All targets are generated from the same simulation source. For the k-th cell, the IQ data for all targets at time n are:

[0089] 6) Under the control of the packaging timer, the R component will process the IQ data of all units. Send the signal to the DBF module for beamforming processing; the timing relationship is shown in the attached figure. Figure 2 t3 packaging preparation time.

Claims

1. A target generation method for all-digital passive array beam testing, characterized in that... Simulation is performed using an in-array monitoring signal fed into the receiving component via an equal-length feeder. To simulate targets pointing in different directions, the spatial phase difference is simulated using in-array phase difference. The steps are as follows: 1) The array control computer reads the pointing value and operating frequency parameters of the simulated target through the display and control interface, and calculates the required intra-array phase difference of the simulated target; 2) The array computer calculates the target parameters and the phase difference parameters within the array based on the simulated parameters. The control command is generated and sent to the system control computer. The simulated target parameters include f0 as the center frequency, PW as the pulse width, PRI as the repetition period, and BW as the signal bandwidth. 3) After receiving the instruction, the system control computer sends control instructions to the equal-length feeder input receiving component and the signal generation module. At the same time, it generates a signal enable timing according to the control instructions, where t1 is the signal enable advance time. The control signal generation module generates a simulated target signal, where t2 is the simulated target pulse width. It generates a sampling timing and controls the equal-length feeder input receiving component to perform signal acquisition. The sampling gate length is the same as the simulated target pulse width. 4) After the signal is collected by the receiving component fed into the equal-length feeder, it is digitally orthogonally down-converted and phase-modulated using the phase compensation value in the array to form analog target data with a specific direction. 5) Under the control of the packing timing, the equal-length feeder input receiving component sends the sampled data of all units to the DBF module for beamforming processing, t3 packing preparation time; Step 1) Calculate the intra-array phase difference required for the simulated target: ； d: the intra-array phase difference required to simulate the target; d: the array cell spacing. Simulated target pointing Then, the k-th unit has k=1,…,N, where N is the total number of antenna elements; Step 4) specifically involves: 4.1) Digital quadrature downconversion processing For the k-th unit, the received signal recorded during the n-th sampling time is: ； Where a(n) is the signal amplitude; The angular frequency corresponding to the intermediate frequency of the signal; This is the phase difference between the analog signal and the local oscillator signal; This is the initial phase of the analog signal; Since the simulated signal uses a conventional pulse signal, the signal amplitude remains constant during the pulse duration, and the signal exhibits time invariance, therefore a(n), , All are constants, using , , express, Will Multiply by respectively and After filtering, we can obtain ； ； 4.2) In-array phase compensation modulation processing Based on the phase compensation value within the simulated target array For k=1, ..., N, we have: ； ； 4.3) Target Data Synthesis All targets are generated from the same simulation source. For the k-th cell, the IQ data for all targets at time n are: .

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