Wideband single-pulse radio frequency array calibration method and system

Abstract

The application provides a broadband single-pulse radio frequency array calibration system and method, which comprises the following steps: a signal generation module of a signal processing unit generates a broadband intermediate frequency signal; the broadband intermediate frequency signal is mixed by an up-conversion link of an antenna feed unit to generate a radio frequency signal, and the radio frequency signal is transmitted to a radio frequency array target simulation system to generate a radiation signal; a receiving antenna of the antenna feed unit receives the radiation signal, and the radiation signal is converted by a down-conversion link to generate an intermediate frequency signal which is transmitted to a signal collection module of the signal processing unit to generate a digital signal; a calibration control unit receives the digital signal, analyzes the digital signal, extracts an amplitude error, a phase error and a time delay error of the broadband signal and corresponding frequency error A(f), generates a broadband radio frequency array compensation parameter based on the amplitude, the phase and the time delay error or the frequency error of the generated broadband signal, and realizes broadband single-pulse radio frequency array calibration based on the generated broadband radio frequency array compensation parameter.

Description

Technical Field

[0001] This invention relates to the field of bandwidth radar hardware-in-the-loop simulation system technology, specifically to a broadband single-pulse radio frequency array calibration method and system, which is mainly used to detect the imaging target simulation performance of a broadband radio frequency array target simulation system. Background Technology

[0002] Imaging radar typically acquires high-resolution target information by emitting wide-bandwidth signals, providing richer target identification information. It has gradually matured and is widely used in target recognition and classification. To verify and evaluate the design of a broadband radar imaging system, a radio frequency array target simulation system is generally used to simulate the dynamic electromagnetic environment of broadband imaging targets encountered by the radar in an outdoor environment. Therefore, the imaging target simulation effect of the radio frequency array target system and the spatial position simulation accuracy of the broadband radar signal are extremely important for calibration.

[0003] Traditional RF array target simulation calibration devices typically operate in single-frequency mode. The radiated signal from the RF array is down-converted to an intermediate frequency (e.g., 100MHz) and then connected to a network analyzer. A phase and amplitude comparison is used to extract the amplitude, phase, and spatial position errors of each radiating element of the array target system at various frequencies, generating a corresponding amplitude and phase compensation table for calibration of the entire RF array target simulation system. This method struggles to extract in-band errors from broadband signals. Therefore, when working with broadband signals, the center frequency compensation data of the broadband signal is usually used for overall compensation. However, this calibration method, due to in-band amplitude and phase fluctuations, can degrade the accuracy of spatial position simulation and cause phenomena such as broadening and cracking of the image of the scattering points of the imaging target. To improve calibration results, multiple single-frequency interpolation compensation within the band or digital processing for RF array compensation are employed. This requires extracting in-band amplitude, phase, and delay errors of the broadband signal and generating corresponding calibration parameters.

[0004] Patent document CN115575910A (application number: 202211062910.3) discloses a calibration system, device and calibration method for a broadband target array, including a main control module, a digital signal processing module, a frequency conversion module and a four-element antenna: the four-element antenna is connected to the frequency conversion module through a microwave cable, the frequency conversion module is connected to the digital signal processing module through a microwave cable and a serial cable, and the digital signal processing module is connected to the main control module through an optical fiber, forming a calibration system for a broadband target array.

[0005] This invention provides a calibration method based on a closed-loop generation and acquisition of broadband single-pulse signals. It generates and acquires broadband signals that pass through the entire link of the radio frequency array target simulation system. Then, it extracts the amplitude, phase, and delay errors of the broadband signals through a signal processing method that combines time and frequency domains, and generates broadband radio frequency array compensation parameters. At the same time, it verifies the imaging target simulation quality and spatial position simulation accuracy of the radio frequency array by acquiring, imaging, and angle measuring the calibrated signals.

[0006] Based on the traditional four-element antenna receiving device, this invention adds a No. 5 receiving antenna placed in the center. This antenna remains in the center position throughout the rotation / movement of the receiving antenna device. Therefore, the distance from the array radiating antenna to this antenna is always consistent, which will not introduce errors and is more conducive to the calibration of the polarization characteristics of the array radiating signal. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a broadband single-pulse radio frequency array calibration method and system.

[0008] A broadband single-pulse radio frequency array calibration system provided by the present invention includes: Module M1: The signal generation module of the signal processing unit generates a broadband intermediate frequency signal; Module M2: The broadband intermediate frequency signal is mixed by the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal, and the radio frequency signal is transmitted to the radio frequency array target simulation system to generate the radiated signal; the receiving antenna of the antenna feed unit receives the radiated signal, and then generates an intermediate frequency signal through the downconversion link, which is transmitted to the signal acquisition module of the signal processing unit to generate a digital signal. Module M3: The calibration control unit receives digital signals and performs data analysis on them, extracting amplitude errors, phase errors, and time delay errors of the broadband signal. Based on the amplitude, phase, and time delay errors of the broadband signal, the corresponding frequency domain errors are extracted. A ( f ), φ ( f Based on the amplitude, phase, and time delay or frequency domain error of the generated broadband signal, broadband RF array compensation parameters are finally generated. Module M4: Performs bandwidth single-pulse RF array calibration based on the generated broadband RF array compensation parameters.

[0009] Preferably, the module M1 includes: Module M1.1: The signal processing unit generates baseband wideband digital signals through the baseband data generation module; (1) in, A 0 indicates the amplitude of the signal;n Indicates the signal sampling rate; T p Indicates pulse width; k=B / T p The frequency modulation slope of the broadband signal; B For signal bandwidth; Module M1.2: Performs digital upmixing on the baseband digital signal to obtain the digital upmixed baseband digital signal; (2) in, f 0 indicates the center frequency of the intermediate frequency signal; Module M1.3: Converts the baseband digital signal after digital upmixing into a broadband intermediate frequency analog signal through a digital-to-analog converter module; (3) in, Indicates the timeline.

[0010] Preferably, in module M2, Module M2.1: The broadband intermediate frequency analog signal is mixed through the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal; (4) Module M2.2: Radio frequency signals are transmitted to the radio frequency array target simulation system to generate radiation signals; (5) in, This represents the corresponding array antenna number; τ represents the signal delay; and A(t) is the signal amplitude error function. The phase error function representing the signal; Module M2.3: The receiving antenna of the antenna feed unit receives the radiated signal, then generates an intermediate frequency signal through the down-conversion link and transmits it to the signal acquisition module of the signal processing unit to generate a digital signal; (6).

[0011] Preferably, in module M2.2, the radio frequency signal is output to the radio frequency array target simulation system to generate a radiated signal via a line feed or by an empty feed through the transceiver antenna of the antenna feed unit.

[0012] Preferably, in module M3, Module M3.1: The calibration control unit receives digital signals and performs down-conversion and digital filtering on the digital signals to obtain baseband echo signals; (7) Module M3.2: Compares the baseband echo signal with the baseband wideband digital signal and extracts their amplitude error. A ( t Phase error φ ( t and time delay error τ ; Module M3.3: Based on the time-frequency coupling characteristics of broadband linear frequency modulated signals, it calculates the corresponding amplitude error. A ( t Phase error φ ( t The error was obtained by converting it to the frequency domain. A ( f ), φ ( f Based on amplitude error A ( t Phase error φ ( t Establish a time-domain compensation coefficient model; obtain the frequency-domain error. A ( f ), φ ( f Frequency domain compensation coefficient model; Module M3.4: Generates broadband RF array compensation parameters based on time-domain compensation coefficient model or frequency-domain compensation coefficient model, and uses broadband RF array compensation parameters to compensate the amplitude and phase response characteristics of the device under test.

[0013] Preferably, For narrowband signals, the frequency points are compensated using time-domain compensation by extracting the amplitude and phase error coefficients corresponding to the frequency points of the error data. For broadband signals, the extracted frequency domain data is fitted to generate filter coefficients. H(n) The amplitude and phase characteristics of the filter are used to compensate for the broadband amplitude and phase characteristics of the device under test.

[0014] A broadband single-pulse radio frequency array calibration method provided by the present invention includes: Step S1: The signal generation module of the signal processing unit generates a broadband intermediate frequency signal; Step S2: The broadband intermediate frequency signal is mixed by the up-conversion link of the antenna feed unit to generate the corresponding radio frequency signal, and the radio frequency signal is transmitted to the radio frequency array target simulation system to generate the radiated signal; the receiving antenna of the antenna feed unit receives the radiated signal, and then generates an intermediate frequency signal through the down-conversion link, which is transmitted to the signal acquisition module of the signal processing unit to generate a digital signal. Step S3: The calibration control unit receives the digital signal and performs data analysis on the digital signal, extracting the amplitude error, phase error, and time delay error of the broadband signal. Based on the amplitude, phase, and time delay errors of the broadband signal, the corresponding frequency domain error is extracted. A ( f ), φ ( f Based on the amplitude, phase, and time delay or frequency domain error of the generated broadband signal, broadband RF array compensation parameters are finally generated. Step S4: Perform bandwidth single-pulse RF array calibration based on the generated broadband RF array compensation parameters.

[0015] Preferably, step S1 includes: Step S1.1: The signal processing unit generates a baseband wideband digital signal through the baseband data generation module; (1) in, A 0 indicates the amplitude of the signal; n Indicates the signal sampling rate; T p Indicates pulse width; k=B / T p The frequency modulation slope of the broadband signal; B For signal bandwidth; Step S1.2: Perform digital upmixing on the baseband digital signal to obtain the baseband digital signal after digital upmixing. (2) in, f 0 indicates the center frequency of the intermediate frequency signal; Step S1.3: Convert the baseband digital signal after digital upmixing into a broadband intermediate frequency analog signal using a digital-to-analog converter module; (3) in, Indicates the timeline.

[0016] Preferably, in step S2, Step S2.1: The broadband intermediate frequency analog signal is mixed by the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal; (4) Step S2.2: The radio frequency signal is transmitted to the radio frequency array target simulation system to generate a radiation signal; (5) in, This represents the corresponding array antenna number; τ represents the signal delay; and A(t) is the signal amplitude error function. The phase error function representing the signal; Step S2.3: The receiving antenna of the antenna feed unit receives the radiated signal, then generates an intermediate frequency signal through the down-conversion link and transmits it to the signal acquisition module of the signal processing unit to generate a digital signal; (6); In step S2.2, the radio frequency signal is output to the radio frequency array target simulation system to generate a radiated signal, either via a line feed or via an empty feed through the transceiver antenna of the antenna feed unit.

[0017] Preferably, in step S3, Step S3.1: The calibration control unit receives the digital signal and performs down-conversion and digital filtering on the digital signal to obtain the baseband echo signal; (7) Step S3.2: Compare the baseband echo signal with the baseband wideband digital signal and extract their amplitude error. A ( t Phase error φ ( t and time delay error τ ; Step S3.3: Based on the time-frequency coupling characteristics of the broadband linear frequency modulated signal, the corresponding amplitude error is... A ( t Phase error φ ( t The error was obtained by converting it to the frequency domain. A ( f ), φ ( f Based on amplitude error A ( t Phase error φ ( t Establish a time-domain compensation coefficient model; obtain the frequency-domain error. A ( f ), φ ( f Frequency domain compensation coefficient model; Step S3.4: Generate broadband RF array compensation parameters based on the time-domain compensation coefficient model or the frequency-domain compensation coefficient model, and use the broadband RF array compensation parameters to compensate the amplitude and phase response characteristics of the device under test; For narrowband signals, the frequency points are compensated using time-domain compensation by extracting the amplitude and phase error coefficients corresponding to the frequency points of the error data. For broadband signals, the extracted frequency domain data is fitted to generate filter coefficients. H(n) The amplitude and phase characteristics of the filter are used to compensate for the broadband amplitude and phase characteristics of the device under test.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention enables broadband target simulation calibration of a radio frequency array target simulation system, allowing the radio frequency array to achieve high-quality imaging target dynamic simulation in space; 2. This invention achieves high-efficiency and high-precision calibration of the radio frequency array by generating and acquiring the broadband signal that passes through the entire link of the radio frequency array target simulation system and extracting the time-domain and frequency-domain compensation coefficients of the broadband signal. 3. This invention is very convenient and efficient in actual use. No other equipment is needed for its later use, and operation and maintenance are relatively simple. Attached Figure Description

[0019] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the antenna layout for the antenna feed unit.

[0020] Figure 2 This is a block diagram illustrating the basic principle of a broadband target array calibration device.

[0021] Figure 3 A schematic block diagram illustrating the operation of a broadband target array calibration system.

[0022] Figure 4 This is a schematic diagram of an FIR filter structure.

[0023] Figure 5 This is a schematic diagram of a target synthesized from two radiating elements of a radio frequency array.

[0024] Figure 6 This is a schematic diagram of the amplitude curves and ideal amplitude curves of two radiating elements of a radio frequency array.

[0025] Figure 7 This is a schematic diagram of the amplitude curves of the radiation element after calibration in the conventional and in this invention.

[0026] Figure 8 This is a schematic diagram showing the imaging effects after calibration of the conventional method and the present invention. Detailed Implementation

[0027] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0028] Example 1 A broadband single-pulse radio frequency array calibration system provided by the present invention includes: Module M1: The signal generation module of the signal processing unit generates a broadband intermediate frequency signal; Module M2: The broadband intermediate frequency signal is mixed by the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal, and the radio frequency signal is transmitted to the radio frequency array target simulation system to generate the radiated signal; the receiving antenna of the antenna feed unit receives the radiated signal, and then generates an intermediate frequency signal through the downconversion link, which is transmitted to the signal acquisition module of the signal processing unit to generate a digital signal. Module M3: The calibration control unit receives digital signals and performs data analysis on them, extracting amplitude errors, phase errors, and time delay errors of the broadband signal. Based on the amplitude, phase, and time delay errors of the broadband signal, the corresponding frequency domain errors are extracted. A ( f ), φ ( f Based on the amplitude, phase, and time delay or frequency domain error of the generated broadband signal, broadband RF array compensation parameters are finally generated. Module M4: Performs bandwidth single-pulse RF array calibration based on the generated broadband RF array compensation parameters.

[0029] Specifically, module M1 includes: Module M1.1: The signal processing unit generates baseband wideband digital signals through the baseband data generation module; (1) in, A 0 indicates the amplitude of the signal; n Indicates the signal sampling rate; T p Indicates pulse width; k=B / T p The frequency modulation slope of the broadband signal; B For signal bandwidth; Module M1.2: Performs digital upmixing on the baseband digital signal to obtain the digital upmixed baseband digital signal; (2) in, f0 indicates the center frequency of the intermediate frequency signal; Module M1.3: Converts the baseband digital signal after digital upmixing into a broadband intermediate frequency analog signal through a digital-to-analog converter module; (3) in, Indicates the timeline.

[0030] Specifically, in module M2, Module M2.1: The broadband intermediate frequency analog signal is mixed through the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal; (4) Module M2.2: Radio frequency signals are transmitted to the radio frequency array target simulation system to generate radiation signals; (5) in, This represents the corresponding array antenna number; τ represents the signal delay; and A(t) is the signal amplitude error function. The phase error function representing the signal; Module M2.3: The receiving antenna of the antenna feed unit receives the radiated signal, then generates an intermediate frequency signal through the down-conversion link and transmits it to the signal acquisition module of the signal processing unit to generate a digital signal; (6).

[0031] Specifically, in module M2.2, the radio frequency signal is output to the radio frequency array target simulation system to generate a radiated signal, either via a line feed or via an empty feed through the transceiver antenna of the antenna feed unit.

[0032] Specifically, in module M3, Module M3.1: The calibration control unit receives digital signals and performs down-conversion and digital filtering on the digital signals to obtain baseband echo signals; (7) Module M3.2: Compares the baseband echo signal with the baseband wideband digital signal and extracts their amplitude error. A ( t Phase error φ ( t and time delay error τ ; Module M3.3: Based on the time-frequency coupling characteristics of broadband linear frequency modulated signals, it calculates the corresponding amplitude error. A ( t Phase error φ ( t The error was obtained by converting it to the frequency domain. A (f ), φ ( f Based on amplitude error A ( t Phase error φ ( t Establish a time-domain compensation coefficient model; obtain the frequency-domain error. A ( f ), φ ( f Frequency domain compensation coefficient model; Module M3.4: Generates broadband RF array compensation parameters based on time-domain compensation coefficient model or frequency-domain compensation coefficient model, and uses broadband RF array compensation parameters to compensate the amplitude and phase response characteristics of the device under test.

[0033] Specifically, For narrowband signals, the frequency points are compensated using time-domain compensation by extracting the amplitude and phase error coefficients corresponding to the frequency points of the error data. For broadband signals, the extracted frequency domain data is fitted to generate filter coefficients. H(n) The broadband amplitude and phase characteristics of the tested device are compensated by utilizing the amplitude and phase characteristics of the filter. This invention employs an FIR filter structure, the principle of which is as follows: Figure 4 As shown.

[0034] A broadband single-pulse radio frequency array calibration method provided by the present invention includes: Step S1: The signal generation module of the signal processing unit generates a broadband intermediate frequency signal; Step S2: The broadband intermediate frequency signal is mixed by the up-conversion link of the antenna feed unit to generate the corresponding radio frequency signal, and the radio frequency signal is transmitted to the radio frequency array target simulation system to generate the radiated signal; the receiving antenna of the antenna feed unit receives the radiated signal, and then generates an intermediate frequency signal through the down-conversion link, which is transmitted to the signal acquisition module of the signal processing unit to generate a digital signal. Step S3: The calibration control unit receives the digital signal and performs data analysis on the digital signal, extracting the amplitude error, phase error, and time delay error of the broadband signal. Based on the amplitude, phase, and time delay errors of the broadband signal, the corresponding frequency domain error is extracted. A ( f ), φ ( f Based on the amplitude, phase, and time delay or frequency domain error of the generated broadband signal, broadband RF array compensation parameters are finally generated. Step S4: Perform bandwidth single-pulse RF array calibration based on the generated broadband RF array compensation parameters.

[0035] Specifically, step S1 includes: Step S1.1: The signal processing unit generates a baseband wideband digital signal through the baseband data generation module; (1) in, A 0 indicates the amplitude of the signal; n Indicates the signal sampling rate; T p Indicates pulse width; k=B / T p The frequency modulation slope of the broadband signal; B For signal bandwidth; Step S1.2: Perform digital upmixing on the baseband digital signal to obtain the baseband digital signal after digital upmixing. (2) in, f 0 indicates the center frequency of the intermediate frequency signal; Step S1.3: Convert the baseband digital signal after digital upmixing into a broadband intermediate frequency analog signal using a digital-to-analog converter module; (3) in, Indicates the timeline.

[0036] Specifically, in step S2, Step S2.1: The broadband intermediate frequency analog signal is mixed by the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal; (4) Step S2.2: The radio frequency signal is transmitted to the radio frequency array target simulation system to generate a radiation signal; (5) in, This represents the corresponding array antenna number; τ represents the signal delay; and A(t) is the signal amplitude error function. The phase error function representing the signal; Step S2.3: The receiving antenna of the antenna feed unit receives the radiated signal, then generates an intermediate frequency signal through the down-conversion link and transmits it to the signal acquisition module of the signal processing unit to generate a digital signal; (6).

[0037] Specifically, in step S2.2, the radio frequency signal is output to the radio frequency array target simulation system to generate a radiated signal in a line-fed or air-fed manner via the transceiver antenna of the antenna feeding unit.

[0038] Specifically, in step S3, Step S3.1: The calibration control unit receives the digital signal and performs down-conversion and digital filtering on the digital signal to obtain the baseband echo signal; (7) Step S3.2: Compare the baseband echo signal with the baseband wideband digital signal and extract their amplitude error. A ( t Phase error φ ( t and time delay error τ ; Step S3.3: Based on the time-frequency coupling characteristics of the broadband linear frequency modulated signal, the corresponding amplitude error is... A ( t Phase error φ ( t The error was obtained by converting it to the frequency domain. A ( f ), φ ( f Based on amplitude error A ( t Phase error φ ( t Establish a time-domain compensation coefficient model; obtain the frequency-domain error. A ( f ), φ ( f Frequency domain compensation coefficient model; Step S3.4: Generate broadband RF array compensation parameters based on the time-domain compensation coefficient model or the frequency-domain compensation coefficient model, and use the broadband RF array compensation parameters to compensate the amplitude and phase response characteristics of the device under test.

[0039] Specifically, For narrowband signals, the frequency points are compensated using time-domain compensation by extracting the amplitude and phase error coefficients corresponding to the frequency points of the error data. For broadband signals, the extracted frequency domain data is fitted to generate filter coefficients. H(n) The broadband amplitude and phase characteristics of the tested device are compensated by utilizing the amplitude and phase characteristics of the filter. This invention employs an FIR filter structure, the principle of which is as follows: Figure 4 As shown.

[0040] Example 2 Example 2 is a preferred example of Example 1. The technical problem to be solved by the present invention is to provide a calibration system and method for high-quality imaging target spatial position dynamic simulation of a broadband radio frequency array target simulation system. By generating and acquiring broadband signals passing through the entire link of the radio frequency array target simulation system, the amplitude, phase, time delay and other errors of the broadband signals are extracted to realize the generation of broadband radio frequency array compensation parameters and array calibration, thereby improving the broadband imaging target dynamic simulation capability of the hardware-in-the-loop simulation test system.

[0041] The broadband single-pulse RF array calibration system includes: an antenna feed module, a signal processing module, and a calibration control module. The antenna feed unit consists of an antenna and up / down conversion links, with one transceiver antenna and four receiving antennas arranged as follows: Figure 1 As shown, the transmit link up-converts the intermediate frequency (IF) signal generated by the signal processing unit to a radio frequency (RF) signal and outputs it to the RF array via a line feed or through a transceiver antenna in an open-circuit feed manner. The receive antenna receives the RF signal radiated by the RF array and then outputs the IF signal to the signal processing unit via a down-conversion link. The signal processing unit consists of a signal generation module and a signal acquisition and processing module. The signal generation module generates a broadband IF signal and outputs it to the up-conversion link of the antenna feed unit. The signal acquisition and processing unit acquires the IF signal output by the antenna feed unit, processes it digitally, and then transmits it to the calibration control unit. The calibration control unit controls the calibration process and timing, acquires the data processed by the signal processing module, analyzes and processes the data, and generates broadband RF array compensation parameters. The system principle block diagram is shown below. Figure 2-3 As shown.

[0042] Specifically, the antenna operating frequency band, beamwidth, gain, and other parameters in the antenna feeding unit are set to meet the actual requirements for receiving and radiating radio frequency signals. Configure the up-conversion and down-conversion RF links in the antenna feed unit to ensure that the input and output ports of the intermediate frequency and RF signals meet the performance requirements such as operating frequency, bandwidth, operating power, and flatness. The signal processing unit is configured to generate an intermediate frequency broadband signal to provide an input signal to the up-conversion RF link in the antenna feed unit, and at the same time, to acquire and process the intermediate frequency signal output by the down-conversion RF link in the antenna feed unit. Configure the interface, communication, and timing protocol of the calibration master control unit to meet the communication and clock synchronization requirements of broadband radio frequency signals between signal transmission and reception throughout the radio frequency array link; Based on the digital signal containing analog errors of the broadband signal of the radio frequency array acquired by the calibration main control unit, an error extraction model for the broadband signal amplitude, phase, etc., is established, and an error compensation model is established, as follows: A transmitted signal model is established, changing the traditional discrete point frequency calibration to instantaneous broadband signal calibration. The theoretical signal model is as follows:

[0043] in, t For time, T p For pulse width, A 0 represents the signal amplitude. f c The center frequency of the signal. k=B / T p The frequency modulation slope of the broadband signal. B This refers to the signal bandwidth.

[0044] The model for acquiring signals can be described as follows:

[0045] In the formula τ For signal delay, A Let be the amplitude error function of the signal. φ Let be the phase error function of the signal, with subscript . i For the first i The signal returned by the array antennas. After further stripping away the delay information, its signal model is as follows:

[0046] The extracted signal error model is obtained by comparing it with the theoretical signal:

[0047] After converting the above error model into a digital signal, it can be expressed as: , n for 0 , 1 / f s , 2 / f s …, f s Signal sampling rate The error data (error matrix) extracted from the above formula can be used to compensate for the amplitude and phase response characteristics of the device under test using both time-domain and frequency-domain methods.

[0048] For narrowband (including point frequency) signals, the frequency points can be compensated by using the amplitude and phase error coefficients of the extracted error data corresponding to the frequency points in the time domain. For broadband signals, the extracted frequency domain data can be fitted to generate filter coefficients. H(n) The broadband amplitude and phase characteristics of the tested device are compensated by utilizing the amplitude and phase characteristics of the filter. This invention employs an FIR filter structure, the principle of which is shown in the figure below.

[0049] This invention provides a calibration system for a broadband radio frequency array target simulation system. By generating and acquiring broadband signals passing through the entire link of the radio frequency array target simulation system, and extracting errors such as amplitude, phase, and time delay of the broadband signals, the system generates broadband radio frequency array compensation parameters and performs array calibration, thereby achieving high-quality imaging target space dynamic simulation.

[0050] The purpose of this invention is to overcome the problem that existing technologies cannot achieve amplitude and phase calibration between broadband radio frequency arrays and between radiating elements.

[0051] Radio frequency arrays simulating dynamic targets are typically synthesized using two or three radiating elements; this example uses two radiating elements. Figure 5 As shown, A and B are radiating elements, and p is the position where the target is synthesized. Taking the amplitude of a broadband signal as an example, as... Figure 6 As shown, a wideband pulse signal (assuming the bandwidth of this wideband pulse signal is 1GHz, and the frequency covers f1 to f2, where f1 is 10GHz and f2 is 11GHz) can be used to extract the amplitude fluctuations and phase error information of frequency points f1 to f2 in one go. Ideally, the amplitudes of frequency points f1 to f2 are consistent, as shown below. Figure 6 As shown, however, there will be fluctuations due to errors, as shown in radiation element A and radiation element B, and the same applies to the phase.

[0052] Traditional calibration methods typically only adjust the overall amplitude within the band, such as... Figure 7 As shown, this will affect the accuracy of spatial position simulation; by using the calibration method of the broadband radio frequency array target simulation system provided by this invention to generate a broadband compensation matrix (broadband error compensation model), a compensation effect close to the ideal state can be achieved through digital modulation or multi-frequency interpolation. Figure 8 The traditional calibration method may result in problems such as widening, splitting, and high sidelobe height in the simulated imaging target. The simulated imaging target after calibration by the present invention has a good focusing effect.

[0053] Example 3 Example 3 is a preferred example of Example 1 and / or Example 2. This invention proposes a calibration method for a broadband radio frequency array target simulation system, which can generate broadband radio frequency array compensation parameters and perform array calibration, thereby improving the dynamic simulation capability of broadband imaging targets in a hardware-in-the-loop simulation test system. Specifically, it is implemented through the following steps: Step 1: Based on the operating frequency band and bandwidth of the radar guidance system, design the operating frequency band, bandwidth, output power, flatness, and other indicators of the antenna feed unit to meet the actual requirements for receiving and radiating radio frequency signals. Step 2: Based on the operating bandwidth of the radar guidance system, design the operating bandwidth, sampling rate, output power, and other indicators of the signal processing unit to meet the actual requirements of broadband signal generation and acquisition. Step 3: Install the antenna feed unit and signal processing unit on the existing turntable to radiate radio frequency signals or receive radiated signals from the radio frequency array; Step 3: Based on the interface, communication, and timing protocols of the entire calibration process, develop intermediate frequency signal generation and acquisition software, as well as signal transmission and reception control methods for the antenna feed unit and signal processing unit; Step 5: Establish a broadband signal error model based on the acquired digital signal, and establish a compensation model based on the actual test error to improve the simulation accuracy of the dynamic characteristics of broadband radio frequency targets; Step Six: Design the control module of the calibration control unit, develop and debug the remote control software, and integrate, debug and test the entire calibration device with other modules.

[0054] The development of this invention, particularly the generation, acquisition, error extraction, and compensation file generation of broadband signals, was quite complex. However, it is very convenient and efficient in practical use, and subsequent use no longer requires the participation of other equipment (such as signal sources or network analyzers), making operation and maintenance relatively simple. This invention generates and acquires broadband signals throughout the entire link of the RF array target simulation system, extracts errors such as amplitude, phase, and time delay of the broadband signals to generate broadband RF array compensation parameters and perform array calibration, enabling the RF array to achieve high-quality dynamic simulation of target space for imaging.

[0055] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0056] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A broadband single-pulse radio frequency array calibration system, characterized in that, include: Module M1: The signal generation module of the signal processing unit generates a broadband intermediate frequency signal; Module M2: The broadband intermediate frequency signal is mixed through the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal, and the radio frequency signal is transmitted to the radio frequency array target simulation system to generate the radiated signal; The receiving antenna of the antenna feed unit receives the radiated signal, which is then converted into an intermediate frequency signal via a down-conversion link and transmitted to the signal acquisition module of the signal processing unit to generate a digital signal. Module M3: The calibration control unit receives digital signals and performs data analysis on them, extracting amplitude errors, phase errors, and time delay errors of the broadband signal. Based on the amplitude, phase, and time delay errors of the broadband signal, the corresponding frequency domain errors are extracted. A ( f ), φ ( f Based on the amplitude, phase, and time delay or frequency domain error of the generated broadband signal, broadband radio frequency array compensation parameters are finally generated. Module M4: Implements broadband single-pulse RF array calibration based on the generated broadband RF array compensation parameters; Module M3.3: Based on the time-frequency coupling characteristics of broadband linear frequency modulated signals, it calculates the corresponding amplitude error. A ( t Phase error φ ( t The error was obtained by converting it to the frequency domain. A ( f ), φ ( f A frequency domain compensation coefficient model is established based on amplitude error. A ( t Phase error φ ( t Establish a time-domain compensation coefficient model; Module M3.4: Generates broadband RF array compensation parameters based on time-domain compensation coefficient model or frequency-domain compensation coefficient model, and uses broadband RF array compensation parameters to compensate the amplitude and phase response characteristics of the device under test; For narrowband signals, the frequency points are compensated using time-domain compensation by extracting the amplitude and phase error coefficients corresponding to the frequency points of the error data. For broadband signals, the extracted frequency domain data is fitted to generate filter coefficients. H(n) The amplitude and phase characteristics of the filter are used to compensate for the broadband amplitude and phase characteristics of the device under test.

2. The broadband single-pulse radio frequency array calibration system according to claim 1, characterized in that, The module M1 includes: Module M1.1: The signal processing unit generates baseband wideband digital signals through the baseband data generation module; （1） in, A 0 indicates the amplitude of the signal; n Indicates the signal sampling rate; T p Indicates pulse width; k=B / T p The frequency modulation slope of the broadband signal; B For signal bandwidth; Module M1.2: Performs digital upmixing on the baseband digital signal to obtain the digital upmixed baseband digital signal; （2） in, f 0 indicates the center frequency of the intermediate frequency signal; Module M1.3: Converts the baseband digital signal after digital upmixing into a broadband intermediate frequency analog signal through a digital-to-analog converter module; （3） in, Indicates the timeline.

3. The broadband single-pulse radio frequency array calibration system according to claim 2, characterized in that, In module M2, Module M2.1: The broadband intermediate frequency analog signal is mixed through the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal; （4） in, A 0 indicates the amplitude of the signal; T p Indicates pulse width; Module M2.2: Radio frequency signals are transmitted to the radio frequency array target simulation system to generate radiation signals; （5） in, Indicates the corresponding array antenna number; Indicates the first i Signal delay of each array antenna For the first i The amplitude error function of the radiated signal of each array antenna; Indicates the first i Phase error function of the radiated signal of an array antenna; Module M2.3: The receiving antenna of the antenna feed unit receives the radiated signal, then generates an intermediate frequency signal through the down-conversion link and transmits it to the signal acquisition module of the signal processing unit to generate a digital signal; （6）。 4. The broadband single-pulse radio frequency array calibration system according to claim 3, characterized in that, In module M2.2, the radio frequency signal is output to the radio frequency array target simulation system to generate a radiated signal, either via a line feed or via an empty feed through the transceiver antenna of the antenna feed unit.

5. The broadband single-pulse radio frequency array calibration system according to claim 4, characterized in that, In the module M3, Module M3.1: The calibration control unit receives digital signals and performs down-conversion and digital filtering on the digital signals to obtain baseband echo signals; （7） Module M3.2: Compares the baseband echo signal with the baseband wideband digital signal and extracts their amplitude error. A ( t Phase error φ ( t and time delay error τ .

6. A broadband single-pulse radio frequency array calibration method, characterized in that, include: Step S1: The signal generation module of the signal processing unit generates a broadband intermediate frequency signal; Step S2: The broadband intermediate frequency signal is mixed through the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal, and the radio frequency signal is transmitted to the radio frequency array target simulation system to generate the radiated signal; The receiving antenna of the antenna feed unit receives the radiated signal, which is then converted into an intermediate frequency signal via a down-conversion link and transmitted to the signal acquisition module of the signal processing unit to generate a digital signal. Step S3: The calibration control unit receives the digital signal and performs data analysis on the digital signal, extracting the amplitude error, phase error, and time delay error of the broadband signal. Based on the amplitude, phase, and time delay errors of the broadband signal, the corresponding frequency domain error is extracted. A ( f ), φ ( f Based on the amplitude, phase, and time delay or frequency domain error of the generated broadband signal, broadband radio frequency array compensation parameters are finally generated. Step S4: Perform broadband single-pulse radio frequency array calibration based on the generated broadband radio frequency array compensation parameters; Step S3.3: Based on the time-frequency coupling characteristics of the broadband linear frequency modulated signal, the corresponding amplitude error is... A ( t Phase error φ ( t The error was obtained by converting it to the frequency domain. A ( f ), φ ( f A frequency domain compensation coefficient model is established based on amplitude error. A ( t Phase error φ ( t Establish a time-domain compensation coefficient model; Step S3.4: Generate broadband RF array compensation parameters based on the time-domain compensation coefficient model or the frequency-domain compensation coefficient model, and use the broadband RF array compensation parameters to compensate the amplitude and phase response characteristics of the device under test; For narrowband signals, the frequency points are compensated using time-domain compensation by extracting the amplitude and phase error coefficients corresponding to the frequency points of the error data. For broadband signals, the extracted frequency domain data is fitted to generate filter coefficients. H(n) The amplitude and phase characteristics of the filter are used to compensate for the broadband amplitude and phase characteristics of the device under test.

7. The broadband single-pulse radio frequency array calibration method according to claim 6, characterized in that, Step S1 includes: Step S1.1: The signal processing unit generates a baseband wideband digital signal through the baseband data generation module; （1） in, A 0 indicates the amplitude of the signal; n Indicates the signal sampling rate; T p Indicates pulse width; k=B / T p The frequency modulation slope of the broadband signal; B For signal bandwidth; Step S1.2: Perform digital upmixing on the baseband digital signal to obtain the baseband digital signal after digital upmixing. （2） in, f 0 indicates the center frequency of the intermediate frequency signal; Step S1.3: Convert the baseband digital signal after digital upmixing into a broadband intermediate frequency analog signal using a digital-to-analog converter module; （3） in, Indicates the timeline.

8. The broadband single-pulse radio frequency array calibration method according to claim 7, characterized in that, In step S2, Step S2.1: The broadband intermediate frequency analog signal is mixed by the upconversion link of the antenna feed unit to generate the corresponding radio frequency signal; （4） in, A 0 indicates the amplitude of the signal; T p Indicates pulse width; Step S2.2: The radio frequency signal is transmitted to the radio frequency array target simulation system to generate a radiation signal; （5） in, Indicates the corresponding array antenna number; Indicates the first i Signal delay of each array antenna For the first i The amplitude error function of the radiated signal of each array antenna; Indicates the first i Phase error function of the radiated signal from the array antenna; Step S2.3: The receiving antenna of the antenna feed unit receives the radiated signal, then generates an intermediate frequency signal through the down-conversion link and transmits it to the signal acquisition module of the signal processing unit to generate a digital signal; （6）； In step S2.2, the radio frequency signal is output to the radio frequency array target simulation system to generate a radiated signal, either via a line feed or via an empty feed through the transceiver antenna of the antenna feed unit.

9. The broadband single-pulse radio frequency array calibration method according to claim 8, characterized in that, In step S3, Step S3.1: The calibration control unit receives the digital signal and performs down-conversion and digital filtering on the digital signal to obtain the baseband echo signal; （7） Step S3.2: Compare the baseband echo signal with the baseband wideband digital signal and extract their amplitude error. A ( t Phase error φ ( t and time delay error τ .

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