Straight wave and target echo simulation method for semi-active radar guidance introduction equipment

Abstract

The invention relates to the technical field of avionics, in particular to a straight wave and target echo simulation method for semi-active radar guidance introduction equipment, which can realize generation of straight wave baseband signals and target echo signals in intermediate frequency and digital domains. The generation of a straight wave radio frequency signal, a target echo radio frequency signal or a broadband interference radio frequency signal is realized through digital-to-analog conversion and an up-conversion module, and finally the signals are radiated out through a microwave antenna; under a laboratory environment condition, a direct wave signal and a target echo signal can be provided for a semi-physical simulation experiment of radar equipment introduced by a semi-active guidance system, target echo and interference parameters are flexibly set, the method can be applied to the semi-physical simulation experiment of the equipment, the performance of the introduced equipment is comprehensively investigated, the limitation of local testing is avoided, and the test efficiency is improved. Meanwhile, compared with a real external field test, the cost consumption is greatly reduced.

Description

Technical Field

[0001] The invention relates to the field of aviation electronics technology, in particular to a method for simulating direct waves and target echoes of semi-active radar-guided introduction equipment. Background Art

[0002] During the use of a semi-active guidance system introduced radar equipment, simulation testing of its system is an important link. The existing test system for the introduced equipment is mainly used to test the performance indicators of various components of the introduced equipment. The target simulation involved is limited to the local mode and the parameters related to the target interference can only be set to fixed values ​​or change according to a certain rule during the test, and cannot be dynamically modified as the test proceeds. In addition, the actual field test requires a lot of manpower and material resources, the cost is high, and it is necessary to pay attention to the uncertainty caused by factors such as weather environment, which greatly limits the use and performance verification of the semi-active guidance system introduced radar equipment. Summary of the invention

[0003] The purpose of the present invention is to provide a method for simulating direct waves and target echoes of semi-active radar-guided introduced equipment. The simulation method adopts a combination of software and hardware. The target interference parameters can be flexibly modified by using the host computer software and FPGA. At the same time, the host computer can send data to the FPGA in a real-time of 1ms. The system has strong flexibility and real-time performance, avoiding the shortcomings of field tests and local tests.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: A method for simulating direct waves and target echoes of semi-active radar-guided introduction equipment comprises the following steps: S1. First, the hardware part of the simulation method is a radar radio frequency signal simulator, which includes a microwave link unit, a baseband processing unit, a display control unit and a structural unit; the microwave link unit includes a microwave up-conversion module and a microwave frequency synthesis module; the baseband processing unit includes an ADC module, a DAC module, a signal processing board and a storage daughter card; the display control unit includes a switching board, a single board computer and an optical reflection card; the structural unit is mainly composed of a chassis, a backplane and a power supply adopting a CPCI bus architecture, which can provide a data interaction PCIE bus and power supply for each unit board; S2. The FPGA in the baseband processing unit generates a direct wave baseband signal corresponding to the imported radar, wherein the direct wave baseband signal may or may not be added with modulation information, and the direct wave baseband signal without modulation information is Doppler modulated to form an echo baseband signal, and a noise signal of a certain bandwidth is multiplied by the echo baseband signal to form a broadband interference baseband signal; S3. Perform digital-to-analog conversion and microwave up-conversion on the direct wave baseband signal and the target echo baseband signal (or broadband interference baseband signal) through the DAC module and the microwave up-conversion module, and output the direct wave and target echo (or broadband interference) RF signals.

[0005] Furthermore, the function of the microwave up-conversion module is to up-convert the intermediate frequency signal into a radio frequency signal, including three-stage up-conversion, using three independent local oscillator signals as inputs for three-stage up-conversion, converting the analog intermediate frequency signal into a direct wave signal and a target echo simulation signal, and controlling and adjusting the signal power to meet the radio frequency output power requirements required for the simulation; The microwave frequency synthesizer module adopts direct digital frequency synthesis technology to provide local oscillator signals for the up-conversion module and clock synchronization signals for the baseband processing unit.

[0006] Furthermore, the ADC module has the function of performing analog-to-digital conversion on the analog intermediate frequency signal to obtain a digital intermediate frequency signal; The DAC module has the function of performing digital-to-analog conversion on the digital intermediate frequency signal to obtain an analog intermediate frequency signal; The function of the signal processing board is based on digital radio frequency memory (DRFM) technology, using FPGA chips to generate direct wave signals in the digital domain, and at the same time perform Doppler modulation, interference modulation, amplitude and phase modulation on the digital signal to generate target echo signals and interference signals; The function of the memory daughter card is to provide a buffer for the delay of the digital signal.

[0007] Furthermore, the function of the switch board is to provide an external serial port and support information exchange between boards; The function of the single board computer is to carry the target signal generator software, perform human-computer interaction, configure the working mode and parameters, and thus control the output signal; The optical reflector card is used for optical fiber communication.

[0008] Furthermore, the microwave frequency synthesis module is respectively connected to the two microwave up-conversion modules through radio frequency lines, the microwave frequency synthesis module is connected to the baseband processing unit through the radio frequency line, the output of the baseband processing unit is connected to the input of the microwave up-conversion module through the radio frequency line, and the outputs of the two microwave up-conversion modules are respectively connected to the horn antenna through the radio frequency line, so as to radiate the radio frequency signal; the display control unit single-board computer sends control instructions through the chassis backplane PCIE bus, transmits them to the switching board, and then the switching board forwards and controls the boards of the microwave link unit and the baseband processing unit through the backplane PCIE bus.

[0009] The beneficial effects of the present invention are as follows: the direct wave and target echo simulation method of the semi-active radar guidance imported equipment provided by the present invention, when used specifically, the main hardware is a radar radio frequency signal simulator, which can realize the generation of direct wave baseband signals and target echo signals in the intermediate frequency and digital domains, and realize the generation of direct wave radio frequency signals, target echo radio frequency signals or broadband interference radio frequency signals through digital-to-analog conversion and up-conversion modules, and finally radiate them through microwave antennas; under laboratory environmental conditions, direct wave signals and target echo signals (or broadband interference signals) can be provided for the semi-physical simulation experiment of the introduced radar equipment of the semi-active guidance system, and the target echo and interference parameters can be flexibly set, which can be applied to the semi-physical simulation test of this type of equipment, comprehensively examine the performance of the introduced equipment, avoid the limitations of local testing, and greatly reduce cost consumption compared with real field tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the generation principle of direct wave and target echo in the direct wave and target echo simulation method of the semi-active radar guidance introduction equipment provided by the present invention; Figure 2 It is a block diagram of the radar radio frequency signal simulator in the simulation method of the present invention; Figure 3 It is a schematic diagram of the broadband interference generation principle in the simulation method of the present invention. DETAILED DESCRIPTION

[0011] Specific embodiment 1: The technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. It should be noted that: in the present invention, if there is no special description, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical scheme. In the present invention, if there is no special description, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical scheme. The "scope" disclosed in the present invention is in the form of lower limit and upper limit, which can be one or more lower limits, and one or more upper limits respectively. In the present invention, unless otherwise specified, each reaction or operation step can be carried out sequentially or in sequence.

[0012] As the instruction manual Figure 2 As shown, the present invention provides a method for simulating direct waves and target echoes of semi-active radar-guided introduction equipment, wherein the hardware part of the simulation method is a radar radio frequency signal simulator, and the radar radio frequency signal simulator includes a microwave link unit, a baseband processing unit, a display control unit and a structural unit; The microwave link unit is composed of a microwave up-conversion module and a microwave frequency synthesis module to realize the frequency conversion between the intermediate frequency signal and the radio frequency signal. The function of the microwave up-conversion module is to up-convert the intermediate frequency signal into the radio frequency signal, including three-level up-conversion, which uses three independent local oscillator signals as input for three-level up-conversion, converts the analog intermediate frequency signal into a direct wave signal, a target echo simulation signal, etc., and controls and adjusts the signal power to meet the radio frequency output power requirements required for the simulation; The microwave frequency synthesis module adopts direct digital frequency synthesis technology to provide local oscillator signals for the up-conversion module and clock synchronization signals for the baseband processing unit; The baseband processing unit is composed of a high-speed AD daughter card, a high-speed DA daughter card, a signal processing board and a storage daughter card, which realizes baseband processing of signals and generates direct wave signals, target echo signals, interference signals, etc. The high-speed AD daughter card is the ADC module, and its function is to perform analog-to-digital conversion on the analog intermediate frequency signal to obtain a digital intermediate frequency signal. The high-speed DA daughter card is the DAC module, and its function is to perform digital-to-analog conversion on the digital intermediate frequency signal to obtain an analog intermediate frequency signal; the function of the signal processing board is based on digital radio frequency memory (DRFM) technology, using FPGA chips to generate direct wave signals in the digital domain, and at the same time perform Doppler modulation, interference modulation, amplitude and phase modulation on the digital signal to generate target echo signals, interference signals, etc.; the function of the storage daughter card is to provide a buffer for the delay of the digital signal; The display control unit is composed of a switch board, a single-board computer, and an optical reflector card. Through the user interaction interface, it exchanges data and performs overall control with other units of the radar RF signal simulator. The function of the switch board is to provide an external serial port and support information interaction between boards. The function of the single-board computer is to carry the target signal generator software, perform human-computer interaction, configure the working mode, parameters, etc., and thus control the output signal. The function of the optical reflector card is to perform optical fiber communication. The structural unit is mainly composed of a chassis, backplane, and power supply that adopts the CPCI bus architecture, which can provide data interaction PCIE bus and power supply for each unit board.

[0013] The connection relationship of each component in the radar radio frequency signal simulator in the direct wave and target echo simulation method of the semi-active radar guidance introduction equipment of the present invention is as follows: the microwave frequency synthesis module is respectively connected to the two microwave up-conversion modules through the radio frequency line, the microwave frequency synthesis module is connected to the baseband processing unit through the radio frequency line, the output of the baseband processing unit is connected to the input of the microwave up-conversion module through the radio frequency line, and the output of the two microwave up-conversion modules is respectively connected to the horn antenna through the radio frequency line, so as to radiate the radio frequency signal. The display control unit single board computer sends a control instruction through the chassis backplane PCIE bus, transmits it to the switch board, and then the switch board forwards and controls the microwave link unit and the baseband processing unit board through the backplane PCIE bus.

[0014] As the instruction manual Figure 1 , Instruction Manual Figure 3 As shown, the direct wave modulation realization principle, target echo generation principle, and broadband interference generation principle in the direct wave and target echo simulation method of the present invention are respectively as follows: 1. Implementation principle of direct wave modulation: The direct wave signal of the radar equipment introduced into the semi-active guidance system has two working states, with and without the modulation signal added; when the modulation information is not added, the direct wave baseband signal generated by the baseband processing unit is directly output; when the modulation information is added, the baseband processing unit outputs a frequency modulated signal with subcarrier frequency 1 (corresponding to frequency F1) or subcarrier frequency 2 (corresponding to frequency F2) as the modulation signal, that is, it outputs a direct wave baseband signal with modulation information. The modulated information includes a number (n1) of correction information. For any one of the correction information, two of them are selected from the positive code, the inverse code and 0 to represent; the positive code and the inverse code are both 1 and 0 combined according to a certain rule. For example, when the positive code is 11...11 (n2 1s), the corresponding inverse code is 00...00 (n2 0s); the frequencies F1 and F2 represent logic 1 and logic 0 respectively; the period used to transmit a logic 1 or a logic 0 is T1; the period required to send n1 correction information is T2, and each information is transmitted according to the corresponding duty cycle and period; finally, the information encoded according to a certain rule is modulated onto the direct wave baseband signal, and finally a direct wave baseband signal with modulation information is formed; 2. Target echo generation principle: The target echo generation is realized by Doppler modulation based on the direct wave baseband signal without modulation information; 3. Principle of broadband interference: The broadband interference of radar equipment introduced into this semi-active guidance system is generated based on the interference bandwidth (BW). The Gaussian noise frequency response curve of the corresponding bandwidth is calculated offline by Matlab. After inverse fast Fourier transform (IFFT) and normalized quantization processing, it is pre-stored in the on-chip block random access memory (BRAM). The FPGA performs random first address playback, windowing, superposition and filtering on the noise data in the on-chip block random access memory to obtain a continuous broadband interference baseband signal.

[0015] In summary, the present invention provides a method for simulating direct waves and target echoes of radar equipment with a semi-active guidance system. Based on the working principle of the semi-active guidance system of the introduced equipment and the guidance correction requirements, a direct wave baseband signal corresponding to the introduced equipment radar is generated by FPGA, wherein the direct wave baseband signal may or may not be added with modulation information, and the direct wave baseband signal without modulation information is Doppler modulated to form an echo baseband signal, and a noise signal with a certain bandwidth is multiplied with the echo baseband signal to form a broadband interference baseband signal; finally, the direct wave baseband signal and the target echo baseband signal (or broadband interference baseband signal) are respectively converted into digital and analog and microwave up-converted by a DAC module and a microwave up-conversion module, and the direct wave and target echo (or broadband interference) radio frequency signals are output. This method can be applied to the semi-physical simulation test of the introduced equipment, and can reduce the test cost, save resources, and improve efficiency when performing the performance test of this type of equipment. The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for simulating direct waves and target echoes of semi-active radar-guided guided equipment, characterized in that: The steps include: S1. First, the hardware part of the simulation method is a radar radio frequency signal simulator, which includes a microwave link unit, a baseband processing unit, a display control unit and a structural unit; the microwave link unit includes a microwave up-conversion module and a microwave frequency synthesis module; The baseband processing unit includes an ADC module, a DAC module, a signal processing board and a storage daughter card; the display control unit includes a switching board, a single board computer and an optical reflector card; The structural unit is mainly composed of a chassis, backplane, and power supply using the CPCI bus architecture, which can provide data interaction PCIE bus and power supply for each unit board; S2. The FPGA in the baseband processing unit generates a direct wave baseband signal corresponding to the imported equipment radar, wherein the direct wave baseband signal may or may not be added with modulation information, and the direct wave baseband signal without modulation information is Doppler modulated to form an echo baseband signal, and the noise signal is multiplied by the echo baseband signal to form a broadband interference baseband signal; S3, respectively perform digital-to-analog conversion and microwave up-conversion on the direct wave baseband signal, the target echo baseband signal or the broadband interference baseband signal through the DAC module and the microwave up-conversion module, and output the direct wave, the target echo or the broadband interference RF signal.

2. The method for simulating direct waves and target echoes of a semi-active radar-guided introduction equipment according to claim 1, characterized in that: The function of the microwave up-conversion module is to up-convert the intermediate frequency signal into a radio frequency signal, including three-stage up-conversion, using three independent local oscillator signals as input for three-stage up-conversion, converting the analog intermediate frequency signal into a direct wave signal and a target echo simulation signal, and controlling and adjusting the signal power to meet the radio frequency output power requirements required for the simulation; The microwave frequency synthesizer module adopts direct digital frequency synthesis technology to provide local oscillator signals for the up-conversion module and clock synchronization signals for the baseband processing unit.

3. The method for simulating direct waves and target echoes of a semi-active radar-guided introduction equipment according to claim 2, characterized in that: The ADC module is used to convert the analog intermediate frequency signal into a digital intermediate frequency signal. The DAC module has the function of performing digital-to-analog conversion on the digital intermediate frequency signal to obtain an analog intermediate frequency signal; The function of the signal processing board is based on digital radio frequency memory (DRFM) technology, using FPGA chips to generate direct wave signals in the digital domain, and at the same time perform Doppler modulation, interference modulation, and amplitude and phase modulation on the digital signal to generate target echo signals and interference signals; The function of the memory daughter card is to provide a buffer for the delay of the digital signal.

4. The method for simulating direct waves and target echoes of a semi-active radar-guided introduction equipment according to claim 3, characterized in that: The function of the switch board is to provide an external serial port and support information exchange between boards; The function of the single board computer is to carry the target signal generator software, perform human-computer interaction, configure the working mode and parameters, and thus control the output signal; The optical reflector card is used for optical fiber communication.

5. The method for simulating direct waves and target echoes of semi-active radar-guided guided equipment according to claim 4, characterized in that: The microwave frequency synthesizer module is respectively connected to the two microwave up-conversion modules through radio frequency lines, the microwave frequency synthesizer module is connected to the baseband processing unit through the radio frequency line, the output of the baseband processing unit is connected to the input of the microwave up-conversion module through the radio frequency line, and the outputs of the two microwave up-conversion modules are respectively connected to the horn antenna through the radio frequency line, so as to radiate the radio frequency signal; The display control unit single board computer sends control instructions through the chassis backplane PCIE bus and transmits them to the switch board, which then forwards and controls the boards of the microwave link unit and the baseband processing unit through the backplane PCIE bus.

6. The method for simulating direct waves and target echoes of semi-active radar-guided guided equipment according to claim 4, characterized in that: The direct wave signal of the radar equipment introduced by the semi-active guidance system has two working states, adding and not adding the modulation signal; when the modulation information is not added, the direct wave baseband signal generated by the baseband processing unit is directly output; when the modulation information is added, the baseband processing unit outputs a frequency modulated signal with the frequency F1 corresponding to the subcarrier frequency 1 or the frequency F2 corresponding to the subcarrier frequency 2 as the modulation signal, that is, outputs a direct wave baseband signal with the modulation information; The modulated information includes a number of n1 correction information. For any one of the correction information, two of them are selected from the positive code, the reverse code and 0 to represent; the positive code and the reverse code are both 1 and 0 combined according to a rule. For example, when the positive code is 11...11n2 1s, the corresponding reverse code is 00...00n2 0s; the frequencies F1 and F2 represent logic 1 and logic 0 respectively; the period used to transmit a logic 1 or a logic 0 is T1; The period required for sending n1 correction information is T2, and each information is transmitted according to the corresponding duty cycle and period; finally, the information encoded according to the rule is modulated onto the direct wave baseband signal, and finally a direct wave baseband signal with modulation information is formed.

7. The method for simulating direct waves and target echoes of semi-active radar-guided guided equipment according to claim 4, characterized in that: The target echo is generated by Doppler modulation based on the direct wave baseband signal without modulation information.

8. The method for simulating direct waves and target echoes of semi-active radar-guided guided equipment according to claim 4, characterized in that: The broadband interference of radar equipment introduced into the semi-active guidance system is generated based on the interference bandwidth (BW). The Gaussian noise frequency response curve of the corresponding bandwidth is calculated offline by Matlab. After inverse fast Fourier transform (IFFT) and normalized quantization processing, it is pre-stored in the on-chip block random access memory (BRAM). The FPGA performs random first address playback, windowing, superposition and filtering on the noise data in the on-chip block random access memory to obtain a continuous broadband interference baseband signal.

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