Multi-channel dual-satellite interferometric synthetic aperture radar echo simulation system, method and device

Abstract

The invention provides a multi-channel dual-star interferometric synthetic aperture radar echo simulation system, method and device, comprising: a radio frequency subsystem A, an intermediate frequency subsystem A, a radio frequency subsystem B, an intermediate frequency subsystem B and a digital subsystem, wherein the radio frequency subsystem A, the intermediate frequency subsystem A, the radio frequency subsystem B, the intermediate frequency subsystem B and the digital subsystem are communicatively connected; the digital subsystem is used to generate an echo data file, an external unified working clock signal CLK is input to the radio frequency subsystem A, distributed by the radio frequency subsystem A to the intermediate frequency subsystem A and the radio frequency subsystem B, and distributed by the radio frequency subsystem B to the intermediate frequency subsystem B, the intermediate frequency subsystem A and / or the intermediate frequency subsystem B reads baseband data and processes it to output an InSAR echo signal, the InSAR echo signal can be simulated and output, and the signals between multiple channels have frequency consistency, amplitude consistency and phase consistency.

Description

Technical Field

[0001] The present invention relates to the technical field of radar echo simulation, and in particular to a multi-channel dual-satellite interferometric synthetic aperture radar echo simulation system, method and device. Background Art

[0002] As an active remote sensing device, the dual-satellite interferometric synthetic aperture radar (InSAR) payload generates InSAR images by alternately transmitting pulse signals and analyzing and processing the received echoes. It has been widely used in many fields including terrain mapping, geological exploration, marine research, agricultural and forestry monitoring, disaster analysis, and military surveillance.

[0003] However, the echo signals obtained through actual measurements cannot cover all scenarios and it is difficult to obtain actual measured data. In addition, the working principle of dual-star interferometric synthetic aperture radar (InSAR) requires that the frequency consistency, amplitude consistency, and phase consistency between multiple channels of the dual-star InSAR be good. If the multi-channel consistency is not good, it will lead to main lobe widening, peak drop, and the appearance of false targets, which will seriously affect the system interference accuracy.

[0004] In order to solve these problems, the dual-star interferometric synthetic aperture radar echo simulator has become an important equipment for ground testing of InSAR payloads. It plays a key role in the complete testing and accurate evaluation of various working modes and image quality performance indicators during the development of InSAR payloads.

[0005] In view of this, it is necessary to provide a new type of multi-channel dual-star interferometric synthetic aperture radar echo simulation system, method and device to overcome the above-mentioned defects. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-channel dual-star interferometric synthetic aperture radar echo simulation system, method and device, which can simulate and output echo signals of real-time point targets and playback scene targets of multiple channels, and the signals between multiple channels have good frequency consistency, amplitude consistency and phase consistency.

[0007] The technical solution provided by the present invention is implemented as follows: a multi-channel dual-satellite interferometric synthetic aperture radar echo simulation system,

[0008] The analog system includes: a radio frequency subsystem A, an intermediate frequency subsystem A, a radio frequency subsystem B, an intermediate frequency subsystem B and a digital subsystem, wherein the radio frequency subsystem A, the intermediate frequency subsystem A, the radio frequency subsystem B, the intermediate frequency subsystem B and the digital subsystem are connected to communicate with each other;

[0009] The digital subsystem is used to generate echo data files. The external unified working clock signal CLK is input to the RF subsystem A, distributed by the RF subsystem A to the intermediate frequency subsystem A and the RF subsystem B, and then distributed by the RF subsystem B to the intermediate frequency subsystem B.

[0010] The intermediate frequency subsystem A and / or the intermediate frequency subsystem B reads the baseband data contained in the echo data file and processes and then outputs an InSAR echo signal.

[0011] The RF subsystem A includes a power supply module, a control module, a clock synchronization module, an up-conversion module and an amplitude-phase calibration module. The power supply module is electrically connected to the control module, the clock synchronization module, the up-conversion module and the amplitude-phase calibration module to power them. The control module is communicatively connected to the digital subsystem and the clock synchronization module. The clock synchronization module is communicatively connected to the up-conversion module and the amplitude-phase calibration module, and the up-conversion module is also communicatively connected to the amplitude-phase calibration module.

[0012] The intermediate frequency subsystem A includes a power supply unit, a main control unit, a synchronization unit and an intermediate frequency generating unit. The power supply unit is electrically connected to the main control unit, the synchronization unit and the intermediate frequency generating unit to provide power to them. The main control unit is communicatively connected to the digital subsystem. The synchronization unit is communicatively connected between the main control unit and the intermediate frequency generating unit. The synchronization unit is communicatively connected to the clock synchronization unit.

[0013] The intermediate frequency generation unit includes a data storage module, an intermediate frequency modulation module and a digital-to-analog conversion module, and the intermediate frequency modulation module communicates between the data storage module and the digital-to-analog conversion module. On the other hand, the present invention also provides a multi-channel dual-star interferometric synthetic aperture radar echo simulation method, which uses the multi-channel dual-star interferometric synthetic aperture radar echo simulation system, including the following steps:

[0014] Generate an echo data file using the digital subsystem, and download the echo data file to the data storage module of the intermediate frequency subsystem A and / or the intermediate frequency subsystem B;

[0015] The intermediate frequency modulation module of the intermediate frequency subsystem A reads the baseband data in the data storage module of the intermediate frequency subsystem B, and modulates the baseband data into a digital intermediate frequency signal in real time by the intermediate frequency modulation module of the intermediate frequency subsystem A, and outputs the digital-to-analog conversion module of the intermediate frequency subsystem A to perform digital-to-analog conversion to generate an analog intermediate frequency signal;

[0016] The intermediate frequency modulation module of the intermediate frequency subsystem B reads the baseband data in the data storage module of the intermediate frequency subsystem B, and modulates the baseband data into a digital intermediate frequency signal in real time by the intermediate frequency modulation module of the intermediate frequency subsystem B, and outputs the baseband data to the digital-to-analog conversion module of the intermediate frequency subsystem B for digital-to-analog conversion to generate an analog intermediate frequency signal;

[0017] The intermediate frequency signal is converted into a radio frequency signal through the up-conversion modules of the radio frequency subsystem A and the radio frequency subsystem B, and the InSAR echo signal is output after the radio frequency amplitude and phase are adjusted.

[0018] The multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method comprises the following steps:

[0019] The up-conversion module of the radio frequency subsystem A converts the analog intermediate frequency signal into a radio frequency signal after filtering, frequency conversion and amplification, and the amplitude and phase calibration module changes the amplitude and phase of the radio frequency signal through an electrically adjustable attenuator and an electrically adjustable phase shifter, and then outputs an InSAR echo signal;

[0020] The up-conversion module of the RF subsystem B converts the analog intermediate frequency signal into a radio frequency signal after filtering, frequency conversion and amplification; the amplitude and phase calibration module changes the amplitude and phase of the radio frequency signal through an electrically adjustable attenuator and an electrically adjustable phase shifter and then outputs an InSAR echo signal.

[0021] On the other hand, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the multi-channel dual-star interferometric synthetic aperture radar echo simulation method when executing the program.

[0022] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the multi-channel dual-star interferometric synthetic aperture radar echo simulation method are implemented.

[0023] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of the multi-channel dual-star interferometric synthetic aperture radar echo simulation method are implemented.

[0024] Compared with the existing technology, the beneficial effect is that a multi-channel, highly consistent dual-star interferometric synthetic aperture radar echo simulator can be constructed according to the channel number and interference accuracy requirements of the spaceborne InSAR system. It has the characteristics of good system architecture versatility, strong channel number scalability, good frequency amplitude and phase consistency, etc., which improves the development efficiency and test completeness of the spaceborne InSAR system.

[0025] Other features and advantages of the present invention will be set forth in the following description, and part will be apparent from the description, or can be understood by implementation of the present invention. Features and advantages of the present invention can be realized and obtained by the elements and combinations specifically pointed out in the appended application scope. These and other features of the present invention will become more clearly understood according to the following description and the appended claims, or can be understood by the implementation of the embodiments described in the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 The principle block diagram of the multi-channel dual-satellite interferometric synthetic aperture radar echo simulation system provided by the present invention;

[0028] Figure 2 It is a principle block diagram of a radio frequency subsystem (including radio frequency subsystem A and radio frequency subsystem B) according to an embodiment of the present invention;

[0029] Figure 3 It is a principle block diagram of an intermediate frequency subsystem (including intermediate frequency subsystem A and intermediate frequency subsystem B) of an embodiment of the present invention;

[0030] Figure 4 It is a flow chart of the multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method of the present invention;

[0031] Figure 5 is a principle block diagram of an intermediate frequency modulation module according to an embodiment of the present invention;

[0032] Figure 6 is a principle block diagram of a DAC daughter card according to an embodiment of the present invention;

[0033] Figure 7 is a principle block diagram of an intermediate frequency generating unit according to an embodiment of the present invention;

[0034] Figure 8 is a flow chart of a convolution operation according to an embodiment of the present invention;

[0035] FIG. 9 ( a ) and FIG. 9 ( b ) are diagrams showing the effects of simulated InSAR echo signals according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features. In addition, the meaning of "multiple" and "several" refers to two or more, unless otherwise clearly and specifically defined.

[0038] See also Figure 1 The present invention provides a multi-channel dual-satellite interferometric synthetic aperture radar echo simulation system for simulating synthetic aperture radar echoes of satellite A and satellite B, wherein satellite A and satellite B constitute a dual-satellite interferometric system;

[0039] The analog system includes five subsystems: radio frequency subsystem A, intermediate frequency subsystem A, radio frequency subsystem B, intermediate frequency subsystem B and digital subsystem. The radio frequency subsystem A, intermediate frequency subsystem A, radio frequency subsystem B, intermediate frequency subsystem B and digital subsystem are interconnected for communication; the radio frequency subsystem A and radio frequency subsystem B share a clock signal, the intermediate frequency subsystem A and intermediate frequency subsystem B share a synchronization signal,

[0040] The digital subsystem is used to generate echo data files. The external unified working clock signal CLK is input to the RF subsystem A, distributed by the RF subsystem A to the intermediate frequency subsystem A and the RF subsystem B, and then distributed by the RF subsystem B to the intermediate frequency subsystem B.

[0041] The intermediate frequency subsystem A and / or the intermediate frequency subsystem B reads the baseband data contained in the echo data file and processes and then outputs an InSAR echo signal.

[0042] The digital subsystem mainly completes the human-computer interaction, parameter adjustment and working status display functions of the entire simulator. The digital subsystem serves as the control core and can be in the form of a server, workstation or other type of general-purpose computer. It can realize command control and data transmission of intermediate frequency subsystem A and intermediate frequency subsystem B through Gigabit network or 10 Gigabit network, and command control and status collection of radio frequency subsystem A and radio frequency subsystem B through Gigabit network or serial port.

[0043] The external unified working clock CLK is input to the RF subsystem A, distributed by RF subsystem A to intermediate frequency subsystem A and RF subsystem B, and then distributed by RF subsystem B to intermediate frequency subsystem B, so that the entire system (intermediate frequency subsystem A, intermediate frequency subsystem B, RF subsystem A, RF subsystem B) works under the same clock, realizing the synchronization of the intermediate frequency center frequency, the RF center frequency, and the sampling clock frequency, and ensuring the frequency consistency.

[0044] The frequency range of the intermediate frequency signal is a section of 1-4 GHz, and the frequency range of the radio frequency signal is a section of 8-100 GHz; the intermediate frequency subsystem A and the intermediate frequency subsystem B output N intermediate frequency signals IF_A and IF_B respectively, and the signal output time of the intermediate frequency subsystem B is controlled by the SYNC of the intermediate frequency subsystem A, thereby ensuring the consistency of the output signal time of the intermediate frequency subsystem A and the intermediate frequency subsystem B.

[0045] Furthermore, the RF subsystem A includes a power supply module, a control module, a clock synchronization module, an up-conversion module, and an amplitude-phase calibration module. The power supply module is electrically connected to the control module, the clock synchronization module, the up-conversion module, and the amplitude-phase calibration module to power them. The control module is communicatively connected to the digital subsystem and the clock synchronization module. The clock synchronization module is communicatively connected to the up-conversion module and the amplitude-phase calibration module, and the up-conversion module is also communicatively connected to the amplitude-phase calibration module. It should be noted that, in this embodiment, the structure and principle of the RF subsystem B are consistent with those of the RF subsystem A, so they will not be described one by one here.

[0046] Combine the following Figure 2 The implementation scheme of the RF subsystem (RF subsystem A, RF subsystem B) is described in detail. The power supply module of the RF subsystem A is responsible for the power supply of each module inside the RF subsystem A. The control module of the RF subsystem A is a microcontroller (MCU), which communicates with the digital subsystem through the control module and is mainly responsible for the amplification / attenuation control in the up-conversion module and the setting and storage of the calibration parameters in the amplitude and phase calibration module.

[0047] The clock synchronization module of the RF subsystem A is mainly responsible for the distribution of the input external unified working clock signal CLK, and generates multiple clock signals with the same frequency as CLK and outputs them to other external RF subsystems B, intermediate frequency subsystem A and intermediate frequency subsystem B; the N independently operable up-conversion modules of the RF subsystem A respectively convert the N analog intermediate frequency signals (IF_A) into radio frequency signals (RF_A) through filtering, frequency conversion, amplification and other processing; the N independently operable amplitude and phase calibration modules respectively change the amplitude and phase of the N radio frequency signals (RF_A) through electrically adjustable attenuators and electrically adjustable phase shifters, the amplitude adjustment step of the electrically adjustable attenuator is 0.01dB, and the phase adjustment step of the electrically adjustable phase shifter is 0.1°, so as to achieve precise adjustment of the amplitude consistency and phase consistency of multiple channels and then output InSAR echo signals.

[0048] Similarly, the N independently operable up-conversion modules of the radio frequency subsystem B respectively convert the N analog intermediate frequency signals (IF_B) into radio frequency signals (RF_B) through filtering, frequency conversion, amplification and other processing; the N independently operable amplitude and phase calibration modules respectively change the amplitude and phase of the N radio frequency signals (RF_B) through electrically adjustable attenuators and electrically adjustable phase shifters. The amplitude adjustment step of the electrically adjustable attenuator is 0.01dB, and the phase adjustment step of the electrically adjustable phase shifter is 0.1°, so as to achieve precise adjustment of the amplitude consistency and phase consistency of multiple channels and then output InSAR echo signals.

[0049] Furthermore, the intermediate frequency subsystem A includes a power supply unit, a main control unit, a synchronization unit and an intermediate frequency generating unit. The power supply unit is electrically connected to the main control unit, the synchronization unit and the intermediate frequency generating unit to supply power to them. The main control unit is communicatively connected to the digital subsystem, the synchronization unit is communicatively connected between the main control unit and the intermediate frequency generating unit, and the synchronization unit is communicatively connected to the clock synchronization unit.

[0050] Furthermore, the intermediate frequency generation unit includes a data storage module, an intermediate frequency modulation module and a digital-to-analog conversion module, and the intermediate frequency modulation module communicates between the data storage module and the digital-to-analog conversion module.

[0051] Combine the following Figure 3 The implementation plan of the intermediate frequency subsystem (intermediate frequency subsystem A, intermediate frequency subsystem B) is described in detail, in which the power supply unit is responsible for the power supply of each module inside the intermediate frequency subsystem; the core chip of the main control unit is the central processing unit (CPU), which can be in the form of a computer board, completes the communication with the digital subsystem, and is mainly responsible for the control of the working mode, working parameters, and work flow of the intermediate frequency subsystem, as well as the collection and upload of the status;

[0052] The core of the synchronization unit is the FPGA control mainboard, which is mainly responsible for distributing the external input clock signal CLK to each intermediate frequency generating unit, and generating a synchronization signal SYNC, controlling the output time and pulse repetition frequency (PRF) of each intermediate frequency generating unit (including intermediate frequency generating unit 1...N) of intermediate frequency subsystem A or intermediate frequency subsystem B to output the intermediate frequency signal, that is, the intermediate frequency signal output of all channels of the simulator is controlled by the edge jump of the SYNC signal;

[0053] Each intermediate frequency generation unit specifically includes a data storage module, an intermediate frequency modulation module and a digital-to-analog conversion module that are interconnected. The control core of each intermediate frequency generation unit is the intermediate frequency modulation module, which uses an FPGA chip. The data storage module stores the baseband data of the echo through a memory such as a solid state drive (SSD) and a memory (DDR).

[0054] The intermediate frequency modulation module reads the baseband data in the data storage module and orthogonally modulates it into a digital intermediate frequency signal. The digital-to-analog conversion module uses a digital-to-analog converter (DAC) to convert the digital intermediate frequency signal into an analog intermediate frequency signal for output. The working clocks of the intermediate frequency modulation module and the data conversion module are both derived from the CLK of the synchronization unit, which ensures the consistency of the intermediate frequency center frequency and sampling frequency of different channels.

[0055] like Figure 4 As shown, the present invention provides a multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method, comprising the following steps:

[0056] S1. Generate an echo data file using the digital subsystem, and download the echo data file to the data storage module of the intermediate frequency subsystem A and / or the intermediate frequency subsystem B;

[0057] S2, the intermediate frequency modulation module of the intermediate frequency subsystem A reads the baseband data in the data storage module of the intermediate frequency subsystem B, and the intermediate frequency modulation module of the intermediate frequency subsystem A modulates the baseband data into a digital intermediate frequency signal in real time, and outputs the digital-to-analog conversion module of the intermediate frequency subsystem A to perform digital-to-analog conversion to generate an analog intermediate frequency signal;

[0058] The intermediate frequency modulation module of the intermediate frequency subsystem B reads the baseband data in the data storage module of the intermediate frequency subsystem B, and modulates the baseband data into a digital intermediate frequency signal in real time by the intermediate frequency modulation module of the intermediate frequency subsystem B, and outputs the baseband data to the digital-to-analog conversion module of the intermediate frequency subsystem B for digital-to-analog conversion to generate an analog intermediate frequency signal;

[0059] S3, the intermediate frequency signal is converted into a radio frequency signal through the up-conversion modules of the radio frequency subsystem A and the radio frequency subsystem B, and the InSAR echo signal is output after the radio frequency amplitude and phase are adjusted.

[0060] Step S3 specifically includes:

[0061] S31, the up-conversion module of the radio frequency subsystem A converts the analog intermediate frequency signal into a radio frequency signal through filtering, frequency conversion, and amplification, and the amplitude and phase calibration module changes the amplitude and phase of the radio frequency signal through an electrically adjustable attenuator and an electrically adjustable phase shifter, and then outputs an InSAR echo signal;

[0062] The up-conversion module of the RF subsystem B converts the analog intermediate frequency signal into a radio frequency signal after filtering, frequency conversion and amplification; the amplitude and phase calibration module changes the amplitude and phase of the radio frequency signal through an electrically adjustable attenuator and an electrically adjustable phase shifter and then outputs an InSAR echo signal.

[0063] Next, combine Figure 4The workflow of a channel in the dual-star interferometric synthetic aperture radar echo simulator is described in detail. The digital subsystem uses echo simulation software and tools to calculate the baseband data of point target or scene echo and generate echo data files, and downloads the echo data files to the data storage module of intermediate frequency subsystem A or intermediate frequency subsystem B through a gigabit network or a 10-gigabit network. The synchronization unit of intermediate frequency subsystem A reads the baseband data in the data storage module of intermediate frequency subsystem A, and the intermediate frequency modulation module of intermediate frequency subsystem A modulates the baseband data into a digital intermediate frequency signal in real time, and outputs it to the digital-to-analog conversion module of intermediate frequency subsystem A for digital-to-analog conversion to generate an analog intermediate frequency signal (IF_A);

[0064] Similarly, the synchronization unit of the intermediate frequency subsystem B reads the baseband data in the data storage module of the intermediate frequency subsystem B, and the intermediate frequency modulation module of the intermediate frequency subsystem B modulates the baseband data into a digital intermediate frequency signal in real time, and outputs it to the digital-to-analog conversion module of the intermediate frequency subsystem B for digital-to-analog conversion to generate an analog intermediate frequency signal (IF_B);

[0065] The intermediate frequency analog signal is converted into a radio frequency signal (RF_A, RF_B) through the up-conversion modules of the radio frequency subsystem A and the radio frequency subsystem B respectively, and the InSAR echo signal is output after the radio frequency amplitude and phase are adjusted.

[0066] In this way, the echo signals of different channels come from the same clock source, ensuring frequency consistency and coherence, and the amplitude consistency and phase consistency between channels are guaranteed through precise RF amplitude and phase calibration. In addition, the workflow of all channels of the dual-star interferometric synthetic aperture radar echo simulator is consistent, and the working clock CLK, working time SYNC, etc. are synchronized.

[0067] Further, such as Figure 5 As shown, the specific implementation scheme of the intermediate frequency generation unit is as follows: the intermediate frequency modulation module (FPGA chip) is used as the control core of the intermediate frequency generation unit, the FPGA chip and the DAC sub-card (i.e., the digital-to-analog conversion module) are interconnected through FMC, and when designing the DAC sub-card, the efficiency and stability are improved by fixing the signal position, minimizing the system support and flexible pin allocation.

[0068] The intermediate frequency modulation module (FPGA chip) uses the VPX bus to interconnect with the bus backplane, and the power module and the clock module are electrically connected to the bus backplane. The intermediate frequency modulation module (FPGA chip) is interconnected with the peripherals through the Gigabit network and the 10 Gigabit network. At the same time, 16 DDR4 chips (i.e., data storage modules) are mounted on the intermediate frequency modulation module (FPGA chip). Each chip has a storage capacity of 8Gbit, and a total of 128Gbit of storage space can be achieved. The power module receives the voltage of the power supply unit to convert the working voltage of the intermediate frequency modulation module (FPGA chip), the data storage module, the clock module, etc. The clock module provides a stable working clock for each chip (FPGA chip, DAC chip).

[0069] Further, such as Figure 6 As shown, the specific implementation scheme of the DAC subcard is as follows: the function of the DAC subcard is to convert the generated spaceborne synthetic aperture radar echo analog digital signal into an analog signal, and it is a key module of the spaceborne SAR echo simulator.

[0070] The DAC subcard is connected to the intermediate frequency modulation module (FPGA chip) through FMC. The working clock of the clock chip HMC7044 in the DAC subcard is provided by the clock module. The working clock of the clock module is provided by the external input clock signal CLK. The synchronous reference clock of the DAC chip in the DAC subcard is provided by the clock HMC7044 chip, and its register is configured through the SPI bus. The output clock will divide the input clock according to the value configured in the register; the data in the intermediate frequency modulation module (FPGA chip) is directly sent to the DAC chip through FMC, and then the digital signal is converted into an analog signal for output.

[0071] Furthermore, the following is combined Figure 7 The process of real-time generation of simulated intermediate frequency signals is described in detail: First, the echo signal parameters are set in the echo simulation software of the digital subsystem, including the vertical height and speed, frequency, azimuth physical size, pulse duration, frequency, resolution, etc. of the InSAR. The specific parameters are shown in Table 1;

[0072] Table 1

[0073]

[0074] Generate an echo data file containing the target scattering signal and the transmitted pulse signal (linear frequency modulation signal), and download the echo data file to the SSD memory of the data storage module of the intermediate frequency generation unit through the network. Then, after receiving the data, the intermediate frequency modulation module (FPGA chip) performs real-time convolution operation (FFT and multiplication of the linear frequency modulation signal and the target scattering information are performed separately, and finally the result is inverse FFT to obtain the convolution output) to generate baseband echo data. After digital orthogonal modulation (the real and imaginary parts of the baseband echo signal are multiplied by the carrier respectively and then subtracted), a digital intermediate frequency signal is generated and sent to the digital-to-analog conversion module, and finally the analog intermediate frequency signal is output through the DAC.

[0075] It should be noted that the convolution operation needs to use the range-frequency domain pulse coherence method to generate baseband echo data. The range-frequency domain pulse coherence method is a commonly used algorithm. Its basic principle is to use the superposition characteristics of radar echoes from scattering points in the frequency domain. This method does not process the echo signal in the time domain, but converts the signal to the frequency domain (usually through fast Fourier transform, FFT), and analyzes and processes it in the frequency domain. In the frequency domain, when the radar beam from the SAR platform scans the ground, the signal reflected from each small area (scattering point) on the ground will contribute to the total echo signal with a specific phase and amplitude.

[0076]

[0077] The above formula is the formula of the frequency domain pulse coherence method for point targets. Among them, is the point target expression, is the scattering element impulse response and, is a baseband linear frequency modulation signal.

[0078] According to the above formula, it can be deduced Figure 8 In the convolution framework, according to the frequency domain product corresponding to the time domain convolution, the frequency domain linear frequency modulation signal and the multi-point target scattering signal are respectively subjected to FFT, then multiplied, and finally the result is subjected to IFFT to obtain the convolution output.

[0079] In order to test the integrity, select single-channel and multi-channel output, and output sine wave signals in single-channel mode and linear frequency modulation signals in multi-channel mode. Switch the display control software to direct mode, test the single channel first, set the timing signal, i.e. the pulse repetition period, to 100Hz, the wavelength to 500us, the delay interval to 60us, and select the local sine wave signal, and use an oscilloscope to observe the analog signal output by channel 1. The result is shown in Figure 9 (a). It can be seen that the time interval between the two cursors is 60us, and the wavelength of the sine wave signal occupies a total of 5 large horizontal squares, each square is 100us, and the total is 500us, which proves that the single-channel direct mode design is correct.

[0080] In multi-channel mode, two channel outputs are set, channel 2 and channel 6 are selected, the delays are set to 11us and 21.8us respectively, and the wavelengths are set to 112us. The analog signals of the dual-channel outputs are observed with an oscilloscope. The results are shown in Figure 9(b).

[0081] It can be seen that the linear FM signal of channel 2, that is, the green waveform output delay is 11us, and the linear FM signal of channel 6, that is, the purple waveform output delay is 21.8us. The wavelength occupies a total of 5 horizontal large squares and 3 small squares. Each large square is 20us, and one large square contains 5 small squares, a total of 112us, proving that the multi-channel function is accurate and consistent.

[0082] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method when executing the program;

[0083] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of the multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method are implemented;

[0084] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of the multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method are implemented;

[0085] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0086] In particular, according to some embodiments of the present disclosure, the process described above can be implemented as a computer software program. For example, some embodiments of the present disclosure include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains program code for executing the method shown in the flowchart. In some such embodiments, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device, or installed from a ROM. When the computer program is executed by a processing device, the above-mentioned functions defined in the method of some embodiments of the present disclosure are executed.

[0087] It should be noted that the computer-readable medium recorded in some embodiments of the present disclosure may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In some embodiments of the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In some embodiments of the present disclosure, a computer-readable signal medium may include a mission data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such a propagated mission data signal may take a variety of forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. Computer readable signal media may also be any computer readable medium other than computer readable storage media, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer readable medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0088] In some embodiments, the client and the server may communicate using any currently known or future developed network protocol such as HTTP (HyperTextTransferProtocol), and may be interconnected with any form or medium of digital task data communication (e.g., a communication network). Examples of communication networks include a local area network ("LAN"), a wide area network ("WAN"), an internet (e.g., the Internet), and a peer-to-peer network (e.g., an adhoc peer-to-peer network), as well as any currently known or future developed network.

[0089] The computer-readable medium may be included in the electronic device, or may exist independently without being incorporated into the electronic device. The computer-readable medium carries one or more programs. When the one or more programs are executed by the electronic device, the electronic device: in response to detecting a query operation on a production collaboration document in a switch production line management application, determines the network connection status of the switch production line management application; in response to determining that the network connection status of the switch production line management application represents an offline state, replaces the web page entry information corresponding to the production collaboration document with target entry file information, and loads target web page resource information to display the web page of the production collaboration document offline in the switch production line management application, wherein the target entry file information is file information of a pre-downloaded entry file corresponding to the web page of the production collaboration document, and the target web page resource information is locally stored resource information corresponding to the web page; in response to determining that the network connection status of the switch production line management application represents an online state, and the web page resource information corresponding to the production collaboration document is not stored locally, downloads the web page resource information of the web page from the production line document server, wherein the web page resource information includes an entry file and resource information; according to the web page resource information, displays the web page of the production collaboration document in the switch production line management application, and stores the web page resource information in a local database.

[0090] Computer program code for performing the operations of some embodiments of the present disclosure may be written in one or more programming languages ​​or a combination thereof, including product-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0091] The present invention is not limited to what is described in the specification and implementation modes, and therefore additional advantages and modifications can be easily realized by those skilled in the art. Therefore, without departing from the spirit and scope of the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details, representative devices, and illustrative examples shown and described herein.

Claims

1. A multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method, characterized in that: The following steps are involved: S1. Generate an echo data file using the digital subsystem, and download the echo data file to the data storage module of the intermediate frequency subsystem A and / or the intermediate frequency subsystem B; S2, the intermediate frequency modulation module of the intermediate frequency subsystem A reads the baseband data in the data storage module of the intermediate frequency subsystem B, and the intermediate frequency modulation module of the intermediate frequency subsystem A modulates the baseband data into a digital intermediate frequency signal in real time, and outputs the digital-to-analog conversion module of the intermediate frequency subsystem A to perform digital-to-analog conversion to generate an analog intermediate frequency signal; The intermediate frequency modulation module of the intermediate frequency subsystem B reads the baseband data in the data storage module of the intermediate frequency subsystem B, and modulates the baseband data into a digital intermediate frequency signal in real time by the intermediate frequency modulation module of the intermediate frequency subsystem B, and outputs the baseband data to the digital-to-analog conversion module of the intermediate frequency subsystem B for digital-to-analog conversion to generate an analog intermediate frequency signal; S3, the intermediate frequency signal is converted into a radio frequency signal through the up-conversion modules of the radio frequency subsystem A and the radio frequency subsystem B, and the InSAR echo signal is output after the radio frequency amplitude and phase are adjusted.

2. The multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method according to claim 1, characterized in that: The following steps are involved: The up-conversion module of the radio frequency subsystem A converts the analog intermediate frequency signal into a radio frequency signal after filtering, frequency conversion and amplification, and the amplitude and phase calibration module changes the amplitude and phase of the radio frequency signal through an electrically adjustable attenuator and an electrically adjustable phase shifter, and then outputs an InSAR echo signal; The up-conversion module of the radio frequency subsystem B converts the analog intermediate frequency signal into a radio frequency signal after filtering, frequency conversion and amplification; The amplitude and phase calibration module changes the amplitude and phase of the RF signal through an electrically adjustable attenuator and an electrically adjustable phase shifter and then outputs an InSAR echo signal.

3. A multi-channel dual-satellite interferometric synthetic aperture radar echo simulation system, characterized in that: The multi-channel dual-star interferometric synthetic aperture radar echo simulation system executes the multi-channel dual-star interferometric synthetic aperture radar echo simulation method according to any one of claims 1 to 2. The analog system includes: a radio frequency subsystem A, an intermediate frequency subsystem A, a radio frequency subsystem B, an intermediate frequency subsystem B and a digital subsystem, wherein the radio frequency subsystem A, the intermediate frequency subsystem A, the radio frequency subsystem B, the intermediate frequency subsystem B and the digital subsystem are connected to communicate with each other; The digital subsystem is used to generate echo data files. The external unified working clock signal CLK is input to the RF subsystem A, distributed by the RF subsystem A to the intermediate frequency subsystem A and the RF subsystem B, and then distributed by the RF subsystem B to the intermediate frequency subsystem B. The intermediate frequency subsystem A and / or the intermediate frequency subsystem B reads the baseband data contained in the echo data file and processes and then outputs an InSAR echo signal.

4. The multi-channel dual-satellite interferometric synthetic aperture radar echo simulation system according to claim 3, characterized in that: The RF subsystem A includes a power supply module, a control module, a clock synchronization module, an up-conversion module and an amplitude-phase calibration module. The power supply module is electrically connected to the control module, the clock synchronization module, the up-conversion module and the amplitude-phase calibration module. The control module is communicatively connected to the digital subsystem and the clock synchronization module. The clock synchronization module is communicatively connected to the up-conversion module and the amplitude-phase calibration module, and the up-conversion module is also communicatively connected to the amplitude-phase calibration module.

5. The multi-channel dual-satellite interferometric synthetic aperture radar echo simulation system according to claim 3, characterized in that: The intermediate frequency subsystem A includes a power supply unit, a main control unit, a synchronization unit and an intermediate frequency generating unit. The power supply unit is electrically connected to the main control unit, the synchronization unit and the intermediate frequency generating unit. The main control unit is communicatively connected to the digital subsystem. The synchronization unit is communicatively connected between the main control unit and the intermediate frequency generating unit. The synchronization unit is communicatively connected to the clock synchronization unit.

6. The multi-channel dual-satellite interferometric synthetic aperture radar echo simulation system according to claim 5, characterized in that: The intermediate frequency generation unit includes a data storage module, an intermediate frequency modulation module and a digital-to-analog conversion module, and the intermediate frequency modulation module communicates between the data storage module and the digital-to-analog conversion module.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the multi-channel dual-star interferometric synthetic aperture radar echo simulation method as described in any one of claims 1 to 2 are implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method according to any one of claims 1 to 2 are implemented.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the multi-channel dual-satellite interferometric synthetic aperture radar echo simulation method according to any one of claims 1 to 2 are implemented.

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