Method and system for simulating broadband signal influenced by Doppler frequency in satellite communication

Abstract

The embodiment of the invention discloses a broadband signal simulation method and system influenced by Doppler frequency in satellite communication. The method comprises the following steps: sampling a received original broadband signal according to an original sampling rate, and obtaining a signal value of a sampling point in real time; discretizing the sampling time of the original broadband signal at the original sampling rate and after the original broadband signal is influenced by the Doppler effect to obtain a first discrete time value and a second discrete time value; storing the signal value and the first time value in a plurality of filter banks in parallel; based on the second time value and the first time value, triggering the filter bank to perform interpolation operation on the stored signal value to obtain a signal interpolation; and performing frequency modulation on the original broadband signal based on the carrier frequency, the relative speed and the output signal interpolation to form a target signal. According to the method, the signal conversion process can be simulated through the simulation technology, the low-cost performance test requirement of the satellite communication system is met, and meanwhile processing time and resource consumption are reduced according to the multiple filter banks.

Description

Technical Field

[0001] The present disclosure relates to the field of signal simulation technology, and particularly to a broadband signal simulation method and system affected by Doppler frequency in satellite communication. Background Art

[0002] In the field of satellite communication, with the development of communication technology, broadband communication has become the mainstream. When a satellite operates at a high speed (such as reaching the first cosmic velocity), the Doppler effect is significant, which will cause the frequency offset of broadband signals, seriously affecting signal demodulation and communication quality. Therefore, the design, testing, and optimization of satellite communication systems must consider this effect.

[0003] In traditional narrowband communication, due to the narrow bandwidth, the influence of Doppler frequency shift is small, and this effect can be ignored. However, broadband signals are more sensitive to it, and the problem of frequency offset under high-speed movement is prominent, challenging the system performance. Moreover, evaluating the performance of satellite communication systems often requires a large number of field tests, which are costly and restricted by factors such as weather and equipment availability. Summary of the Invention

[0004] In view of this, the embodiments of the present disclosure provide a broadband signal simulation method affected by Doppler frequency in satellite communication, which can simulate the signal conversion process through simulation technology, meet the low-cost performance test requirements of satellite communication systems, and at the same time reduce processing time and resource consumption based on multiple filter banks.

[0005] In a first aspect, the embodiments of the present disclosure provide a broadband signal simulation method affected by Doppler frequency in satellite communication, adopting the following technical solutions: Obtain the original sampling rate of the original broadband signal, the carrier frequency of the satellite, and the relative velocity between the satellite and the receiving end; Receive the original broadband signal, sample the original broadband signal at the original sampling rate, and obtain the signal values of the sampling points in real time; Discretize the original broadband signal at the original sampling rate and the sampling time affected by the Doppler effect respectively to obtain discrete first time values and second time values; Parallelly store the signal values obtained in real time and the first time values into multiple filter banks; Based on the second time values and the first time values stored in the filter banks, trigger the filter banks to perform interpolation operations on the stored signal values to obtain signal interpolations; Sort the signal interpolations according to the working timings of multiple filter banks, and output the sorted signal interpolations at the original sampling rate; Based on the carrier frequency, the relative velocity, and the output signal interpolations, perform frequency modulation on the original broadband signal to form a target signal, where the target signal is a broadband signal affected by Doppler frequency.

[0006] Optionally, obtain the original sampling rate of the original broadband signal, the carrier frequency of the satellite, and the relative velocity between the satellite and the receiving end; Receive the original broadband signal, sample the original broadband signal according to the original sampling rate, and obtain the signal values of the sampling points in real time; Discretize the sampling times of the original broadband signal at the original sampling rate and affected by the Doppler effect respectively, and obtain discrete first time values and second time values; Parallelly store the signal values and the first time values obtained in real time into multiple filter banks; Based on the second time value and the first time value stored in the filter bank, trigger the filter bank to perform interpolation operation on the stored signal values to obtain signal interpolation; Sort the signal interpolation according to the working timings of multiple filter banks, and output the sorted signal interpolation according to the original sampling rate; Based on the carrier frequency, the relative velocity, and the output signal interpolation, perform frequency modulation on the original broadband signal to form a target signal, where the target signal is a broadband signal affected by the Doppler frequency.

[0007] Optionally, the parallelly storing the signal values and the first time values obtained in real time into multiple filter banks includes: Parallelly store the signal values obtained in real time into the first FIFO data buffers of multiple filter banks; Parallelly store the first time values obtained in real time into the second FIFO data buffers of multiple filter banks.

[0008] Optionally, the triggering the filter bank to perform interpolation operation on the stored signal values based on the second time value and the first time value stored in the filter bank to obtain signal interpolation includes: Extract a start value and an operation value from the second time value; Determine a target number according to the number sequence of the filter bank, and send the target number, the start value, and the operation value to each filter bank; When the number of the filter bank is the same as the target number, trigger the filter bank to compare the received start value with the earliest stored second time value in the second FIFO data buffer; If the comparison is consistent, obtain signal interpolation based on the signal values stored in the filter bank and the received operation value.

[0009] Optionally, the extracting a start value and an operation value from the second time value includes: Extract the integer part of the second time value as the start value; Extract the fractional part of the second time value as the operation value.

[0010] Optionally, obtaining the signal interpolation based on the signal values stored in the filter bank and the received operation value includes: Construct a signal column vector based on the signal values stored in the filter bank; Obtain a matrix-mapped signal vector based on the signal column vector and a preset interpolation matrix; Obtain a decreasing exponential column vector of the operation value based on the order N of the interpolation matrix; Obtain the signal interpolation based on the matrix-mapped signal vector and the decreasing exponential column vector.

[0011] Optionally, frequency modulating the original broadband signal based on the carrier frequency, the relative speed, and the output signal interpolation to form a target signal includes: Obtain the Doppler frequency based on the carrier frequency and the relative speed; Obtain a complex signal value based on the Doppler frequency; Obtain a signal sample value based on the complex signal value and the output signal interpolation; Output the signal sample values in sequence to form a target signal.

[0012] Optionally, the method for simulating a broadband signal affected by Doppler frequency in satellite communication further includes: Store the start value and the operation value into a start value buffer queue and an operation value buffer queue respectively; Control the start and stop of the second counter based on the remaining storage space sizes of the start value buffer queue and the operation value buffer queue.

[0013] In a second aspect, an embodiment of the present disclosure further provides a system for simulating a broadband signal affected by Doppler frequency in satellite communication, adopting the following technical solution: A system for simulating a broadband signal affected by Doppler frequency in satellite communication includes a signal front-end processing module, a plurality of filter banks, a Doppler calculation module, a sequential value-taking module, a FIFO buffer, and a reset item rotation multiplier; The input end of the signal front-end processing module is connected to the output end of a signal source; The output end of the signal front-end processing module is connected to the input end of the Doppler calculation module and the input ends of the plurality of filter banks; The input end of the Doppler calculation module is further connected to the output end of a configuration module; The output end of the Doppler calculation module is connected to the input ends of the plurality of filter banks and the input end of the reset item rotation multiplier; The output ends of the multiple filter banks are connected to the input end of the sequential value-taking module; The sequential value-taking module, the FIFO buffer, and the reset term rotation multiplier are connected in sequence.

[0014] Optionally, the signal front-end processing module includes a signal receiver and a first counter, and each of the multiple filter banks includes a first FIFO data buffer and a second FIFO data buffer; The input end of the signal receiver is connected to the output end of the signal source; The output end of the signal receiver is respectively connected to the input end of the first counter and the input end of the first FIFO data buffer; The output end of the first counter is connected to the input end of the second FIFO data buffer.

[0015] Optionally, the Doppler calculation module includes a second counter, a first arithmetic unit, a start value cache queue, an operation value cache queue, a second arithmetic unit, a direct digital frequency synthesizer, and a controller, and each of the multiple filter banks further includes a comparator and a digital signal processor; The input end of the second counter is connected to the output end of the signal receiver, and the input end of the first arithmetic unit is connected to the output end of the second counter and the output end of the configuration module; The output end of the first arithmetic unit is connected to the input end of the start value cache queue and the input end of the operation value cache queue, and the input end of the controller is connected to the output end of the start value cache queue and the output end of the operation value cache queue; The input end of the comparator is connected to the output end of the controller and the output end of the second FIFO data buffer, and the controller is further connected to the second counter and the digital signal processor; The input end of the digital signal processor is connected to the output end of the comparator and the output end of the first FIFO data buffer, and the output end of the digital signal processor is connected to the input end of the sequential value-taking module; The input end of the second arithmetic unit is connected to the output end of the configuration module, and the output end of the second arithmetic unit is connected to the input end of the direct digital frequency synthesizer; The output end of the direct digital frequency synthesizer is connected to the input end of the reset term rotation multiplier.

[0016] The broadband signal simulation method affected by Doppler frequency in satellite communication provided by the embodiments of the present disclosure can accurately incorporate the Doppler effect into the broadband signal simulation by obtaining the original sampling rate of the original signal, the carrier frequency of the satellite, and the relative velocity between the satellite and the receiving end. By obtaining the signal values of the sampling points in real time and discretizing the sampling times of the original broadband signal at the original sampling rate and after being affected by the Doppler effect respectively, the dynamic simulation of the Doppler effect in the time dimension is realized. This means that the situation of the signal being affected by Doppler frequency shift at different times can be simulated, so as to more comprehensively understand the change characteristics of the signal and provide support for dealing with complex situations in actual communication. The signal values and the first time values obtained in real time are stored in multiple filter banks in parallel, taking advantage of parallel processing and greatly improving the efficiency of data storage. Based on the second time value and the first time values stored in the filter banks, the filter banks are triggered to perform interpolation operations on the stored signal values, and the signal interpolation can be accurately obtained. After being affected by the Doppler effect, the sampling time of the signal changes, and the appropriate signal values can be obtained at the new time points through interpolation operations, thus ensuring the continuity and accuracy of the signal. The signal interpolations are sorted according to the working timings of the multiple filter banks, and the sorted signal interpolations are output at the original sampling rate, which can ensure that the output signal interpolations have the correct order and avoid the signal from being chaotic and distorted. Based on the carrier frequency, relative velocity, and the output signal interpolations, frequency modulation is performed on the original broadband signal to form a broadband signal affected by Doppler frequency. This frequency modulation method can accurately reflect the Doppler effect in the target signal, making the generated target signal more in line with the signal characteristics in actual satellite communication. The generated target signal can be used to evaluate and test the performance of the satellite communication system. For example, by analyzing indicators such as the bit error rate and signal-to-noise ratio of the target signal, the performance of the system under the influence of the Doppler effect can be evaluated, providing a basis for the optimization and improvement of the system.

[0017] The above description is only an overview of the technical solutions of the present disclosure. In order to understand the technical means of the present disclosure more clearly, it can be implemented according to the content of the description. And in order to make the above and other purposes, features, and advantages of the present disclosure more obvious and understandable, the following preferred embodiments are specifically given and described in detail in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1Schematic flowchart of the broadband signal simulation method affected by Doppler frequency in satellite communication provided by the embodiments of the present disclosure; Figure 2 Schematic circuit diagram of the signal modulation circuit provided by the embodiments of the present disclosure; Figure 3 Schematic flowchart of the sampling time discretization provided by the embodiments of the present disclosure; Figure 4 Schematic flowchart of the parallel storage method provided by the embodiments of the present disclosure; Figure 5 Schematic flowchart of the filter bank control method provided by the embodiments of the present disclosure; Figure 6 Schematic flowchart of the signal interpolation calculation method provided by the embodiments of the present disclosure; Figure 7 Schematic flowchart of the target signal formation method provided by the embodiments of the present disclosure; Figure 8 Time-frequency diagram of the original broadband signal provided by the embodiments of the present disclosure; Figure 9 Time-frequency diagram of the target signal provided by the embodiments of the present disclosure; Figure 10 Phase difference diagram provided by the embodiments of the present disclosure; Detailed implementation manners The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0020] It should be clear that the following uses specific specific examples to illustrate the implementation manners of the present disclosure, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. The present disclosure can also be implemented or applied through other different specific implementation manners, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without making creative efforts belong to the scope of protection of the present disclosure.

[0021] Note that the following describes various aspects of embodiments within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on this disclosure, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement a device and / or practice a method. Additionally, this device and / or method can be implemented using other structures and / or functionality in addition to one or more of the aspects described herein.

[0022] It should also be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present disclosure. Only the components related to the present disclosure are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in its actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0023] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the aspects described can be practiced without these specific details.

[0024] Referring to Figure 1 , the present disclosure provides a method for simulating a broadband signal affected by Doppler frequency in satellite communication, including the following steps: S1: Obtain the original sampling rate of the original broadband signal, the carrier frequency of the satellite, and the relative velocity between the satellite and the receiving end; S2: Receive the original broadband signal, sample the original broadband signal at the original sampling rate, and obtain the signal values of the sampling points in real time; S3: Discretize the sampling time of the original broadband signal at the original sampling rate and after being affected by the Doppler effect respectively, and obtain discrete first time values and second time values; S4: Store the signal values obtained in real time and the first time values in parallel into multiple filter banks; S5: Based on the second time values and the first time values stored in the filter banks, trigger the filter banks to perform interpolation operations on the stored signal values to obtain signal interpolations; S6: Sort the signal interpolations according to the working timings of the multiple filter banks, and output the sorted signal interpolations at the original sampling rate; S7: Based on the carrier frequency, relative velocity, and the output signal interpolations, perform frequency modulation on the original broadband signal to form a target signal, and the target signal is a broadband signal affected by Doppler frequency.

[0025] The broadband signal simulation method affected by Doppler frequency in satellite communication provided by the present disclosure can accurately incorporate the Doppler effect into the broadband signal simulation by obtaining the original sampling rate of the original signal, the carrier frequency of the satellite, and the relative velocity between the satellite and the receiving end. In satellite communication, due to the relative motion between the satellite and the receiving end, the Doppler frequency shift phenomenon occurs, which has a significant impact on signal transmission and reception. This method takes into account these key factors, making the simulation results more in line with the actual satellite communication scenario and providing more reliable data for subsequent system design and performance evaluation. By obtaining the signal values of the sampling points in real time and discretizing the sampling time of the original broadband signal at the original sampling rate and after being affected by the Doppler effect respectively, the dynamic simulation of the Doppler effect in the time dimension is realized, which means that the situation of the signal being affected by the Doppler frequency shift at different times can be simulated, so as to more comprehensively understand the change characteristics of the signal and provide support for dealing with complex situations in actual communication.

[0026] The signal values and the first time values obtained in real time are stored in multiple filter banks in parallel, taking advantage of parallel processing and greatly improving the efficiency of data storage. When processing broadband signals, the data volume is usually large. If the serial storage method is used, it may lead to a slow processing speed and even data backlog. Parallel storage can make full use of the resources of multiple filter banks to speed up the data storage speed and ensure that the system can process a large amount of signal data in real time.

[0027] Based on the second time value and the first time value stored in the filter bank, the filter bank is triggered to perform interpolation operations on the stored signal values, and the signal interpolation can be accurately obtained. After being affected by the Doppler effect, the sampling time of the signal changes. Through interpolation operations, appropriate signal values can be obtained at new time points, thus ensuring the continuity and accuracy of the signal. This interpolation processing method has strong flexibility and can be adjusted according to different simulation requirements and scenarios. For example, under different satellite motion states, the influence degree of the Doppler effect is different. By adjusting the interpolation algorithm and parameters, various complex situations can be better adapted, and the accuracy and reliability of the simulation can be improved.

[0028] Sort the signal interpolation according to the working timings of multiple filter banks and output the sorted signal interpolation at the original sampling rate. This can ensure that the output signal interpolation has the correct order and avoid signal confusion and distortion. In an actual satellite communication system, the correct order of the signal is crucial for subsequent demodulation, decoding and other processes. This method ensures the integrity of the signal through sorting operations. Outputting the signal interpolation at the original sampling rate makes the output signal have the same sampling rate as the original broadband signal, which is convenient for compatibility and docking with subsequent systems, reducing additional sampling rate conversion operations and lowering the complexity and processing cost of the system.

[0029] Based on the carrier frequency, relative velocity, and output signal interpolation, frequency modulation is performed on the original broadband signal to form a broadband signal affected by the Doppler frequency. This frequency modulation method can accurately reflect the Doppler effect in the target signal, making the generated target signal more in line with the signal characteristics in actual satellite communication. The generated target signal can be used to evaluate and test the performance of the satellite communication system. For example, by analyzing indicators such as the bit error rate and signal-to-noise ratio of the target signal, the performance of the system under the influence of the Doppler effect can be evaluated, providing a basis for system optimization and improvement.

[0030] In S1, the user can manually input the original sampling rate of the original broadband signal, the carrier frequency of the satellite, and the relative velocity between the satellite and the receiving end through the interface of the configuration module, and then the configuration module transmits these data to the subsequent module for calculation. Here, the receiving end refers to the device that receives the target signal.

[0031] In S2, a signal receiver is set up, and its function is to receive the original broadband signal output by the signal source. The original sampling rate of the original broadband signal is the input sampling rate. At this time, the original broadband signal has not been affected by the Doppler effect and does not meet the test requirements of satellite communication. Therefore, it is necessary to perform frequency modulation on the original broadband signal to add the influence of the Doppler effect and complete the simulation of the Doppler signal. Before the adjustment, the signal receiver will first sample the original broadband signal according to the original sampling rate, obtain the sampling points in real time, and record the signal values of these sampling points. The unit of the signal value is bit. These recorded signal values will be used as the basic data for subsequent interpolation operations.

[0032] Refer to Figure 2 The shown signal modulation circuit schematic diagram optimizes the signal processing architecture inside the field-programmable gate array (FPGA), and then optimizes the signal simulation mechanism. Sig_in represents the original broadband signal emitted by the signal source, and SR represents the signal receiver. SR is responsible for receiving Sig_in, sampling it according to the original sampling rate, and then outputting the signal values of these sampling points, denoted as 、 、…、 、…。

[0033] In S3, the core objective of signal simulation is to achieve the sampling rate conversion of the original broadband signal, that is, to convert the original broadband signal at the original sampling rate into a broadband signal with Doppler frequency shift characteristics by simulating the influence of the Doppler frequency. This process requires determining the time points corresponding to the original broadband signal under the original sampling rate condition, and the time points corresponding to the signal after being affected by the Doppler effect. Discretization, as the key process of converting a continuous-time signal into a discrete-time signal, can clearly determine the discrete time points of the original broadband signal at the original sampling rate and after being affected by the Doppler effect through discretization, thereby providing a necessary basis for the signal conversion process. Refer to Figure 3 As shown in the schematic diagram of the sampling time discretization process in Figure 3 , "discretize the sampling times of the original broadband signal at the original sampling rate and after being affected by the Doppler effect respectively to obtain discrete first time values and second time values" includes the following steps: S31: When the original broadband signal is received, start the first counter and the second counter simultaneously. The counting frequency of the second counter is higher than that of the first counter; S32: Use the count value of the first counter to represent the discrete first time value; S33: Obtain the conversion factor based on the relative velocity and the speed of light; S34: Obtain the discrete second time value based on the count value of the second counter and the conversion factor.

[0034] In the above steps, receiving the original broadband signal is a trigger point, at which time the first counter and the second counter are started simultaneously. Among them, the count value of the first counter is used to represent the sampling time point value after discretization of the original broadband signal at the original sampling rate, denoted as the first time value, and these first time values constitute the normalized time axis of the original broadband signal; the count value of the second counter is used to represent the sampling time point value after discretization of the original broadband signal affected by the Doppler effect, denoted as the second time value, and these second time values constitute the normalized time axis of the original broadband signal (i.e., the target signal) affected by the Doppler effect.

[0035] Since the Doppler effect can change the spectrum of the original broadband signal, which in turn affects the phase and time characteristics of the original broadband signal, there will be a difference in time between the signal affected by the Doppler effect and the original broadband signal. To accurately compare and process the original broadband signal and the signal affected by the Doppler effect, it is necessary to align them in time, which is usually achieved by means of interpolation operations. To facilitate the interpolation operation, the time resolution after the interpolation operation can be made higher, that is, the discrete time points need to be denser, which requires the counting frequency of the second counter to be higher than that of the first counter, so that the rate at which the second counter generates time axis markers is greater than that of the first counter, thereby obtaining a finer time discretization value and providing a better time reference for accurate interpolation. For example, if the counting frequency of the first counter is 100 MHz, then the counting frequency of the second counter can be set to 400 MHz.

[0036] Among them, the second time value is equal to the product of the count value of the second counter and the conversion factor. The conversion factor refers to the proportionality factor for the compression and stretching of the original broadband signal in the case of high-speed motion. Among them, the calculation formula for the second time value is as follows: ; (Formula 1) In Formula 1, is the time series index of the target signal, used to mark the order of each count of the second counter and the generation order of the second time value; is the th second time value; is the th count value generated by the second counter; is the conversion factor, is the ratio between the relative speed and the speed of light, that is , is the relative speed; is the speed of light.

[0037] Referring to Figure 2 , CNT1 represents the first counter, CNT1 is connected to the signal receiver SR, used to bind and output Sig_in, and CNT2 represents the second counter. When SR receives the original broadband signal, it sends a start instruction to CNT1 and CNT2. After receiving the start instruction, the first counter and the second counter start counting at their respective frequencies. The first counter generates the first time value in real time, denoted as , , …, , …. CNT1 and SR together constitute the signal front-end processing module. The signal front-end processing module is represented as FE in Figure 2 , which is used to receive and process the original broadband signal and output the signal value of the sampling point and the corresponding first time value . The count value generated by the second counter is denoted as , ,…, ,…, AU1 represents the first arithmetic unit, which is used to calculate the second time value according to the count value generated by the second counter and the relative speed output by the configuration module .

[0038] In order to accurately process and analyze the original broadband signal at the original sampling rate, and considering the change of signal characteristics affected by the Doppler frequency, it is necessary to align the time points of the signal at the original sampling rate with the equivalent time points of the signal affected by the Doppler frequency. By using the numerical increment function of the first counter and the second counter, the discretization of time is realized, and the discretized first time value and second time value are obtained. The discretized first time value and second time value provide a basis for the alignment of such signal time points, enabling the comparison and processing of the time points of the original broadband signal at the original sampling rate with the corresponding (although the frequency of the affected signal changes, but they can be associated through the time correspondence relationship) time points of the signal affected by the Doppler frequency. In addition, the discretized signal values and time values make the signal processing more flexible. In a digital signal processing system, these discrete values can be efficiently stored and processed, thus supporting various complex signal processing algorithms and providing a strong guarantee for accurately analyzing the characteristics of broadband signals affected by the Doppler effect and realizing applications such as precise detection and positioning of targets.

[0039] In S4, referring to Figure 4 the flow schematic diagram of the parallel storage method shown, "parallelly storing the signal value and the first time value obtained in real time into multiple filter banks" includes the following steps: S41: Parallelly store the signal value obtained in real time into the first FIFO data buffer of multiple filter banks; S42: Parallelly store the first time value obtained in real time into the second FIFO data buffer of multiple filter banks.

[0040] In the above steps, referring to Figure 2 , multiple filter banks are preset in advance. These filter banks parallelly complete the interpolation operation of the signal value, thereby improving the conversion speed of the original broadband signal. The number of filter banks can be freely adjusted according to FPGA resources. Each filter bank has its own number, such as FB1, FB2, …, FB h ,…, FB H , where h is the number and H is the total number of filter banks.

[0041] To facilitate each filter to process signal values in a timely manner according to time points, the signal values and the corresponding first time values need to be stored in parallel in the corresponding FIFO data buffers (First - In - First - Out Data Buffer). Each filter bank includes two FIFO data buffers with the feature of first - in - first - out. When the data buffer is full and new data arrives, the earliest stored data (at the head of the data queue) is removed, and then the new data is stored at the tail of the data queue. One of the FIFO data buffers is used to store signal values, denoted as the first FIFO data buffer; the other is used to store the first time values, denoted as the second FIFO data buffer. In Figure 2 it, Buffer1 represents the first FIFO data buffer, and Buffer2 represents the second FIFO data buffer.

[0042] The method of storing the signal values and the first time values obtained in real - time in parallel in each filter bank can, on the one hand, facilitate subsequent interpolation operations. The storage can establish the correspondence between the signal values and the first time values, which is conducive to accurate interpolation according to the time points at the original sampling rate. It can also perform targeted interpolation on the stored signals using the characteristics of the filter bank to improve accuracy and efficiency. On the other hand, it helps to achieve parallel processing and improve efficiency. Multiple filter banks work in parallel, which can give full play to the advantages of parallel processing, shorten the signal conversion time, and meet the requirements of real - time signal processing. In addition, it is also convenient for the sorting and output of signal interpolation, providing a unified data source for sorting, adapting to the differences in the working time sequences of different filter banks, and ensuring that when frequency - modulating the original broadband signal based on the carrier frequency, relative speed, and output signal interpolation, a target signal affected by the Doppler frequency is successfully formed, ensuring the stability and accuracy of the target signal output.

[0043] In S5, referring to Figure 5 the schematic flow diagram of the filter bank control method shown, "triggering the filter bank to perform interpolation operations on the stored signal values based on the second time value and the first time value stored in the filter bank to obtain signal interpolations" includes the following steps: S51: Extract the start value and operation value from the second time value; S52: Determine the target number in the order of the filter bank numbers, and send the target number, start value, and operation value to each filter bank; S53: When the number of the filter bank is the same as the target number, trigger the filter bank to compare the received start value with the earliest stored second time value in the second FIFO data buffer; if the comparison is consistent, execute S54; if the comparison is inconsistent, execute S55; S54: Obtain signal interpolations based on the signal values stored in the filter bank and the received operation value; S55: Tasks that do not trigger interpolation operations.

[0044] In the above steps, the start value is used to trigger the filter bank to start interpolation operations, and the operation value is used to combine with the corresponding signal value to participate in the specific interpolation operation process. First, the second time value is processed by splitting it into an integer part and a fractional part, where the integer part serves as the start value and the fractional part serves as the operation value. Then, the target numbers are determined in ascending order of the filter bank numbers, starting from the smallest number as the first target number. Subsequently, through the data transmission channel, the extracted start value, operation value, and target number are sent to each filter bank. After receiving the target number, each filter bank checks whether its own number is the same as the received target number. When the number of the filter bank is the same as the target number, the filter bank reads the earliest stored second time value from its second FIFO data buffer. Since the second FIFO data buffer has the feature of first-in, first-out, the earliest stored second time value is at the head of the buffer. The start value received by the filter bank is numerically compared with the read second time value. When the comparison is consistent, it indicates that the current time point meets the trigger condition for the filter bank to perform interpolation operations. At this time, the filter bank can be triggered to perform interpolation operations on the signal values stored in the first FIFO data buffer, that is, the filter bank calculates the signal interpolation according to the received operation value and the stored signal values according to the preset interpolation algorithm. When the comparison is inconsistent, it indicates that the current time point has not yet met the requirements for the filter bank to perform interpolation operations, and at this time, the interpolation operation task of the filter bank is not triggered.

[0045] Refer to Figure 2 , the first arithmetic unit AU1 and the counter CNT2 are part of the Doppler calculation module. The Doppler calculation module is used to control each filter bank to perform interpolation operations. This module also includes a controller, which is represented as CTRL, and the Doppler calculation module is represented as SRC. After calculating the second time value, the first arithmetic unit AU1 extracts the start value and the operation value from it. Int represents the start value, and frac represents the operation value. For example, when the second time values are [0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5] respectively, the extracted start values are Int = [0, 0, 1, 1, 2, 2, 3, 3], and the operation values are frac = [0, 0.5, 0, 0.5, 0, 0.5, 0, 0.5]. CTRL determines the target number in the order of the filter bank numbers. In Figure 2 , the target number is represented by Target. For example, the initial value of Target is number 1, and then it will successively become number 2, number 3, until number H. After traversing all the numbers, polling will continue, starting from number 1 again.

[0046] Each filter bank includes a comparator and a digital signal processor. In Figure 2 , the comparator is represented by CMP, and the digital signal processor is represented by DSP. CTRL sends Int and Target to the CMP of each filter bank, and sends frac to the DSP of each filter bank. After receiving these data, the CMP further triggers the comparison between Int and the second time value stored earliest in the second FIFO data buffer Buffer2 of the filter bank by comparing the number of the filter bank where it is located with Target. When both of these comparisons meet the conditions, the start operation of the interpolation operation for the filter bank can be completed. At this time, the CMP sends an operation instruction to the DSP, and after receiving the operation instruction, the DSP starts the interpolation operation through frac.

[0047] Furthermore, the counting frequency of the second counter is relatively high, which makes the real-time generation speed of the second time value also relatively fast. In order to process the generated second time value in a timely manner, a start value cache queue and an operation value cache queue are configured in the Doppler calculation module. Among them, the start value cache queue is used to store the generated start value, and the operation value cache queue is used to store the generated operation value. The remaining storage space sizes of the start value cache queue and the operation value cache queue are monitored in real time. When the remaining storage space size of any one of the cache queues is lower than the first threshold, it means that the cache queue is about to be full, and the counting operation of the second counter is paused. Continue to monitor the remaining storage space size of the cache queue. When the remaining storage space size is higher than the second threshold, it indicates that the cache queue has released enough space, and the second counter is restarted. When the remaining storage space size of any one of the cache queues is higher than the third threshold, it means that the buffered data in the cache queue is about to be used up, and at this time, the counting frequency of the second counter needs to be increased.

[0048] In Figure 2 , BQ1 represents the start value cache queue, BQ2 represents the operation value cache queue. CTRL not only extracts Int and frac from BQ1 and BQ2 respectively, but also monitors the remaining storage space sizes of BQ1 and BQ2 in real time, and controls the start and stop of the second counter through their remaining storage space sizes.

[0049] By configuring the start value cache queue and the operation value cache queue to process the generated start value and operation value with high frequency in a timely manner, monitoring the remaining storage space of the cache queue in real time, pausing counting to prevent overflow when it is lower than the first threshold, restarting counting to ensure continuity when it is higher than the second threshold, and increasing the counting frequency when it is higher than the third threshold to dynamically respond to the situation that the buffered data is about to be used up, the data processing efficiency, stability and flexibility can be improved.

[0050] When the filter bank is triggered for the interpolation operation task, the filter bank starts to calculate the signal interpolation. Refer to Figure 6Schematic flow diagram of the signal interpolation calculation method shown, "obtaining signal interpolation based on the signal values stored in the filter bank and the received operation values" includes the following steps: S541: Construct a signal column vector based on the signal values stored in the filter bank; S542: Obtain a matrix-mapped signal vector based on the signal column vector and a preset interpolation matrix; S543: Obtain a decreasing exponential column vector of the operation value based on the order N of the interpolation matrix; S544: Obtain signal interpolation based on the matrix-mapped signal vector and the decreasing exponential column vector.

[0051] In the above steps, the interpolation matrix is an N×N matrix. Set the number of storage units of Buffer1 and Buffer2 to be equal to the order N, so that the number of signal values stored in the filter bank and the number of first time values are always N. This not only facilitates aligning the signal values with the first time values, but also helps in subsequent calculations of the signal values stored in the filter bank and the interpolation matrix. First, construct the signal values stored in the filter bank into a signal column vector. The expression of the signal column vector is as follows: ; (Formula 2) In Formula 2, is the time series index of the original width signal, used to mark the generation order of the signal values. The order of marking the signal values is consistent with the order of each count of the first counter, and at the same time, the order of each count of the first counter is also the generation order of the first time value; is the signal column vector; is the th signal value; is the transpose of the matrix.

[0052] The interpolation matrix can be generated by various methods such as the sinc method (Sinc function method) and the Lagrange method. The general expression of the interpolation matrix is as follows: ; (Formula 3) In Formula 3, is the interpolation matrix, … is the element value of the interpolation matrix.

[0053] Taking the Lagrange method as an example, construct an interpolation matrix with N = 4. For each interpolation point and , calculate the polynomial coefficients through the Lagrange interpolation polynomial. Among them, , , the expression of the Lagrange interpolation polynomial is as follows: ; (Formula 4) In Equation 4, is the independent variable; is the Lagrange basis function.

[0054] Substitute values into Equation 4 respectively, and calculate the , , , polynomial coefficients. These polynomial coefficients form a coefficient matrix, and the expression of the coefficient matrix is as follows: ; (Equation 5) In Equation 5, is the coefficient matrix.

[0055] The calculation result of the interpolation matrix is as follows: ; (Equation 6) Multiply the signal column vector by the interpolation matrix to obtain an N + 1-order matrix-mapped signal vector. Calculate the decreasing exponential column vector of the operation values according to the order N of the matrix. The elements in the decreasing exponential column vector are the powers of the operation values, and the powers decrease from N - 1 until 0. Among them, the expression of the decreasing exponential column vector is as follows: ; (Equation 7) In Equation 7, is the decreasing exponential column vector.

[0056] Transpose the decreasing exponential column vector and multiply it by the matrix-mapped signal vector and then sum to obtain the signal interpolation. Among them, the calculation formula of the signal interpolation is as follows: ; (Equation 8) In Equation 8, is the signal interpolation calculated by the th filter bank.

[0057] Referring to Figure 2 , the digital signal processor DSP reads the signal values from the first FIFO data buffer Buffer1, forms a signal column vector with the read signal values, and then calculates the signal interpolation in combination with the operation value frac sent by the controller CTRL. The row vector composed of the extracted operation values can be analogized to the time axis, and the calculated signal interpolations are equivalent to the signal sampling values corresponding to each time point on this time axis. For example, assume that the starting value calculated by the Doppler calculation module is 24. In the filter bank FB1, the input signal flows through in sequence. When the first time value of 24 is stored, the condition is triggered, and the interpolation operation starts. The calculation result is output as: 0.4677 + 0.8839i, which is sent to the FIFO buffer and output according to the original sampling rate of 100Mhz.

[0058] In S6, the filter bank performs operations in sequence according to its numbering order. Therefore, the working timing sequence of the filter bank is determined by the numbering order. The filter bank numbers corresponding to signal interpolation are arranged in ascending order, and according to this sorting order, the signal interpolation is stored in the FIFO buffer. The field-programmable gate array will output the sorted signal interpolation in the FIFO buffer at the original sampling rate.

[0059] Refer to Figure 2 , SVM represents the sequential value-taking module, FIFOCache represents the FIFO buffer. The SVM is responsible for arranging the filter bank numbers corresponding to signal interpolation in ascending order and storing the signal interpolation in the FIFOCache according to this sorting order. By this method, it can ensure that the field-programmable gate array correctly outputs the signal interpolation in order. The output order of the signal interpolation from the FIFOCache from front to back is ,... ,... , ,... ,...

[0060] In S7, refer to Figure 7 The flow schematic diagram of the target signal formation method shown, "Frequency-modulate the original broadband signal based on the carrier frequency, relative velocity, and the output signal interpolation to form the target signal" includes the following steps: S71: Obtain the Doppler frequency based on the carrier frequency and relative velocity; S72: Obtain the complex signal value based on the Doppler frequency; S73: Obtain the signal sample value based on the complex signal value and the output signal interpolation; S74: Output the signal sample values in sequence to form the target signal.

[0061] In the above steps, the Doppler calculation module is also used to calculate the complex signal value and transmit it to the reset term rotation multiplier. Among them, the complex signal is a signal expressed in complex form, which can simultaneously reflect the amplitude and phase information of the signal, and its frequency is the same as the Doppler frequency. During the continuous generation of the complex signal, each exact time point corresponds to a specific value of the complex signal, and this value is the complex signal value, which changes with time. Each time the FIFO buffer outputs a signal interpolation, the reset term rotation multiplier multiplies the signal interpolation by the received complex signal value to obtain the corresponding signal sample value. Output these signal sample values in sequence according to the output order of the signal interpolation, and these sequentially output signal sample values together form the target signal affected by the Doppler frequency.

[0062] Among them, the calculation formula of the Doppler frequency is as follows: ; (Equation 9) In Equation 9, is the Doppler frequency; is the carrier frequency.

[0063] The Doppler calculation module further includes a second arithmetic unit and a direct digital synthesizer (DDS). In Figure 2 , AU2 represents the second arithmetic unit, DDS represents the direct digital synthesizer, RTRM represents the reset term rotation multiplier, s(t) represents the complex signal value at the t-th moment, represents the signal sample value generated based on the h-th filter bank. The second arithmetic unit calculates the Doppler frequency based on the carrier frequency output by the configuration module and the relative velocity . DDS generates a complex signal based on the Doppler frequency and outputs s(t). RTRM multiplies s(t) by to obtain and output the signal sample value. The output order of the signal sample values from front to back is 、…、 、…、 、 、…、 、…, and these sequentially output signal sample values form the target signal.

[0064] In summary, the Doppler calculation module accurately controls the calculation process of the filter bank according to the original sampling rate of the original broadband signal and the relative velocity between the signal source and the receiver. Assuming that 4 filter banks are configured, when the data of each sampling point arrives, the combinations of filter banks participating in the work may be [1], [1,2], [1,2,3], or [1,2,3,4], that is, the number of activated filter banks will change in real time with the data volume. Each filter bank will work according to the instructions issued by the Doppler calculation module to calculate the signal interpolation. The output results of filter banks 1-4 may be presented as [O1], [O1,O2], [O1, O2,O3], or [O1, O2,O3,O4]. These calculated signal interpolations will be sent to the sequential value-taking module for sorting. In this way, the FPGA can use multiple filter banks simultaneously to complete the signal interpolation, accelerating the signal processing speed. Moreover, when the original sampling rate of the original broadband signal or other relevant parameters change, this method can still effectively introduce the influence of the Doppler frequency into the original broadband signal, improving the flexibility of signal conversion, enabling the simulation task to more accurately and efficiently simulate the actual scenario affected by the Doppler frequency in satellite communication, and providing a more reliable basis for the design, testing, and optimization of the satellite communication system.

[0065] Taking the original sampling rate of 1200 MHz as an example, a wideband swept complex signal with a bandwidth of 240 MHz is constructed and used as the original wideband signal. The duration and idle time of the original wideband signal are both set to 1×10⁻ 5 seconds. Refer to Figure 8 the time-frequency diagram of the original wideband signal shown in Figure 9 and the time-frequency diagram of the target signal shown in 8 . During the process of signal conversion through four filter banks, the Doppler effect at different relative speeds is analyzed. In the exploration of extreme cases, when the relative motion speed of the two satellites reaches 2×7900 = 15800 m / s (i.e., 2 times the first cosmic velocity), although the Doppler effect is manifested, since this speed is extremely small compared to the speed of light, its influence effect is not significant. When the relative speed increases to 0.6c (c is the speed of light in vacuum, approximately 3×10 8 m / s, 0.6c is 1.8×10

[0066] m / s), the conversion factor is 2, and the Doppler effect causes an obvious compression phenomenon of the signal. Specifically, the length of the signal after Doppler compression becomes 1 / 2 of the original, and at the same time, the bandwidth of the original wideband signal expands to 2 times the original, and the time is halved. This result fully conforms to the simulation expectation. Figure 10 Fixing the relative speed at 2 times the first cosmic velocity and keeping other parameters unchanged, referring to

[0067] the phase difference diagram between the original wideband signal and the target signal presented in Figure 2 . At the initial stage of the simulation, the phases of the original wideband signal and the target signal are consistent. However, as the simulation progresses to the end, a phase difference of -22° is generated between the two. This phenomenon fully indicates that this simulation method can accurately reflect the influence of the Doppler effect on wideband signals under high-speed motion conditions, has good simulation effects and reliability, and is applicable to the simulation of wideband Doppler signals at the first cosmic velocity. The input end of the signal front-end processing module is connected to the output end of the signal source; The output end of the signal front-end processing module is connected to the input end of the Doppler calculation module and the input ends of multiple filter banks; The input end of the Doppler calculation module is also connected to the output end of the configuration module; The output end of the Doppler calculation module is connected to the input ends of multiple filter banks and the input end of the reset term rotation multiplier; The output ends of multiple filter banks are connected to the input end of the sequential value-taking module; The sequential value-taking module, the FIFO buffer, and the reset item rotation multiplier are connected in sequence.

[0068] Among them, the Doppler calculation module receives the original sampling rate of the original signal, the carrier frequency of the satellite, and the relative velocity between the satellite and the receiving end sent by the configuration module; the signal front-end processing module receives the original signal transmitted by the signal source, samples the original signal according to the original sampling rate, obtains the signal values of the sampling points in real time, and discretizes the sampling time of the original signal at the original sampling rate to obtain discrete first time values, and stores the signal values and the first time values obtained in real time in parallel into multiple filter banks; The Doppler calculation module discretizes the sampling time of the original signal affected by the Doppler effect to obtain discrete second time values, and based on the second time values and the first time values stored in the filter bank, triggers the filter bank to perform interpolation operations on the stored signal values to obtain signal interpolations; The sequential value-taking module sorts the signal interpolations according to the working timings of multiple filter banks, stores the signal interpolations in the FIFO buffer in the sorted order, and the field-programmable gate array outputs the sorted signal interpolations in the FIFO buffer according to the target sampling rate; The Doppler calculation module obtains the Doppler frequency based on the carrier frequency and the relative velocity, and obtains the complex signal values based on the Doppler frequency; the reset item rotation multiplier obtains the signal sample values based on the complex signal values and the output signal interpolations; and sequentially outputs the signal sample values to form the target signal.

[0069] Furthermore, the signal front-end processing module includes a signal receiver and a first counter, and multiple filter banks all include a first FIFO data buffer and a second FIFO data buffer; The input end of the signal receiver is connected to the output end of the signal source; The output end of the signal receiver is respectively connected to the input end of the first counter and the input end of the first FIFO data buffer; The output end of the first counter is connected to the input end of the second FIFO data buffer.

[0070] Among them, when the signal receiver receives the original signal, it controls the first counter to start counting, uses the count value of the first counter to represent the discrete first time value, and at the same time the signal receiver obtains the signal values of the sampling points in real time through the original sampling rate; stores the signal values obtained in real time in parallel into the first FIFO data buffers of multiple filter banks; stores the first time values obtained in real time in parallel into the second FIFO data buffers of multiple filter banks.

[0071] Further, the Doppler calculation module includes a second counter, a first arithmetic unit, a start value buffer queue, an operation value buffer queue, a second arithmetic unit, a direct digital frequency synthesizer, and a controller. Each of the multiple filter banks further includes a comparator and a digital signal processor; The input end of the second counter is connected to the output end of the signal receiver, and the input end of the first arithmetic unit is connected to the output end of the second counter and the output end of the configuration module; The output end of the first arithmetic unit is connected to the input end of the start value buffer queue and the input end of the operation value buffer queue, and the input end of the controller is connected to the output end of the start value buffer queue and the output end of the operation value buffer queue; The input end of the comparator is connected to the output end of the controller and the output end of the second FIFO data buffer, and the controller is further connected to the second counter and the digital signal processor; The input end of the digital signal processor is connected to the output end of the comparator and the output end of the first FIFO data buffer, and the output end of the digital signal processor is connected to the input end of the sequential value fetching module; The input end of the second arithmetic unit is connected to the output end of the configuration module, and the output end of the second arithmetic unit is connected to the input end of the direct digital frequency synthesizer; The output end of the direct digital frequency synthesizer is connected to the input end of the reset term rotation multiplier.

[0072] Among them, when the signal receiver receives the original signal, it controls the second counter to start counting; the first arithmetic unit obtains a conversion factor according to the relative speed output by the configuration module, and based on the count value of the second counter and the conversion factor, obtains discrete second time values.

[0073] The first arithmetic unit extracts the start value and the operation value from the second time values and stores them in the start value buffer queue and the operation value buffer queue respectively; the controller controls the start and stop of the second counter based on the remaining storage space sizes of the start value buffer queue and the operation value buffer queue.

[0074] The controller also determines the target number in the order of the filter bank numbers, and sends the target number, the start value, and the operation value to each filter bank; when the filter bank number is the same as the target number, it triggers the filter bank to compare the received start value with the earliest stored second time value in the second FIFO data buffer; if the comparison is consistent, based on the signal value stored in the filter bank and the received operation value, signal interpolation is obtained.

[0075] The second arithmetic unit obtains the Doppler frequency based on the carrier frequency and relative speed output by the configuration module; the direct digital frequency synthesizer obtains the complex signal value based on the Doppler frequency output by the second arithmetic unit; the reset term rotation multiplier forms the target signal based on the complex signal value output by the direct digital frequency synthesizer and the signal interpolation output by the FIFO buffer.

[0076] The various change methods and specific examples in the broadband signal simulation method affected by the Doppler frequency in satellite communication provided above are equally applicable to the broadband signal simulation system affected by the Doppler frequency in satellite communication provided by the present disclosure. Through the foregoing detailed description of the broadband signal simulation method affected by the Doppler frequency in satellite communication, those skilled in the art can clearly know the implementation method of the broadband signal simulation system affected by the Doppler frequency in satellite communication. For the sake of brevity of the specification, it will not be elaborated herein.

[0077] The basic principles of the present disclosure have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, benefits, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present disclosure. In addition, the specific details disclosed above are only for the purpose of illustration and facilitating understanding, rather than limitations. The above details do not limit the present disclosure to necessarily adopt the above specific details to implement.

[0078] In the present disclosure, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The block diagrams of the devices, apparatuses, equipment, and systems involved in the present disclosure are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open-ended words, meaning "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used herein refer to the word "and / or", and can be used interchangeably with it, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0079] In addition, as used herein, the "or" used in the listing of items starting with "at least one" indicates a separate listing, so that for example, the listing of "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (that is, A and B and C). In addition, the wording "exemplary" does not mean that the described examples are preferred or better than other examples.

[0080] It should also be noted that in the systems and methods of the present disclosure, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of the present disclosure.

[0081] Various changes, substitutions, and alterations to the technologies described herein can be made without departing from the teachings defined by the appended claims. Additionally, the scope of the claims of the present disclosure is not limited to the specific aspects of the processes, machines, manufactures, compositions of events, means, methods, and acts described above. Processes, machines, manufactures, compositions of events, means, methods, or acts that currently exist or will later be developed and that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Accordingly, the appended claims include such processes, machines, manufactures, compositions of events, means, methods, or acts within their scope.

[0082] The foregoing description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the aspects shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0083] The foregoing description has been presented for purposes of illustration and description. Additionally, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although numerous example aspects and embodiments have been discussed above, those skilled in the art will recognize some of their variations, modifications, alterations, additions, and subcombinations.

Claims

1. A method for simulating a broadband signal affected by Doppler frequency in satellite communication, characterized in that: include: Obtain the original sampling rate of the original broadband signal, the carrier frequency of the satellite, and the relative speed between the satellite and the receiving end; Receiving the original broadband signal, sampling the original broadband signal according to the original sampling rate, and acquiring the signal value of the sampling point in real time; Discretizing the sampling time of the original broadband signal at the original sampling rate and after being affected by the Doppler effect, respectively, to obtain a discrete first time value and a second time value; storing the real-time acquired signal value and the first time value in parallel into a plurality of filter banks; Based on the second time value and the first time value stored in the filter group, triggering the filter group to perform an interpolation operation on the stored signal value to obtain a signal interpolation value; Sorting the signal interpolation according to the working timing of the plurality of filter groups, and outputting the sorted signal interpolation according to the original sampling rate; Based on the carrier frequency, the relative speed and the output signal interpolation, the original broadband signal is frequency modulated to form a target signal, where the target signal is a broadband signal affected by the Doppler frequency.

2. The method for simulating a broadband signal affected by Doppler frequency in satellite communication according to claim 1, characterized in that: The step of discretizing the sampling time of the original broadband signal at the original sampling rate and after being affected by the Doppler effect to obtain a discrete first time value and a discrete second time value comprises: When the original broadband signal is received, the first counter and the second counter are started simultaneously, wherein the counting frequency of the second counter is higher than the counting frequency of the first counter; Using the count value of the first counter to represent a discrete first time value; Based on the relative speed and the speed of light, obtaining a conversion factor; A discrete second time value is acquired based on the count value of the second counter and the conversion factor.

3. The method for simulating a broadband signal affected by Doppler frequency in satellite communication according to claim 2, characterized in that: The step of storing the real-time acquired signal value and the first time value in parallel into a plurality of filter banks comprises: The signal values ​​acquired in real time are stored in parallel in the first FIFO data buffers of the plurality of filter banks; The first time value acquired in real time is stored in parallel in the second FIFO data buffers of the plurality of filter banks.

4. The method for simulating a broadband signal affected by Doppler frequency in satellite communication according to claim 3, characterized in that: The step of triggering the filter group to perform an interpolation operation on the stored signal value based on the second time value and the first time value stored in the filter group to obtain a signal interpolation value includes: extracting a start value and an operation value from the second time value; Determine a target number according to the numbering sequence of the filter groups, and send the target number, the start value and the operation value to each filter group; When the number of the filter group is the same as the target number, triggering the filter group to compare the received start value with the second time value stored earliest in the second FIFO data buffer; If the comparison is consistent, a signal interpolation value is obtained based on the signal value stored in the filter bank and the received operation value.

5. The method for simulating a broadband signal affected by Doppler frequency in satellite communication according to claim 4, characterized in that: The extracting the start value and the operation value from the second time value comprises: extracting an integer part of the second time value as a start value; The decimal part of the second time value is extracted as a calculation value.

6. The method for simulating a broadband signal affected by Doppler frequency in satellite communication according to claim 4, characterized in that: The obtaining of signal interpolation based on the signal value stored in the filter bank and the received operation value comprises: constructing a signal column vector based on the signal values ​​stored in the filter bank; Based on the signal column vector and a preset interpolation matrix, obtaining a matrix mapping signal vector; Obtaining a decreasing exponential column vector of the operation value based on the order N of the interpolation matrix; A signal interpolation is obtained based on the matrix mapping signal vector and the decreasing index column vector.

7. The method for simulating a broadband signal affected by Doppler frequency in satellite communication according to claim 1, characterized in that: The method of frequency modulating the original broadband signal based on the carrier frequency, the relative speed and the output signal interpolation to form a target signal comprises: Based on the carrier frequency and the relative speed, obtaining a Doppler frequency; Based on the Doppler frequency, obtaining a complex signal value; Obtaining a signal sample value based on the complex signal value and the output signal interpolation; The signal sample values ​​are outputted in sequence to form a target signal.

8. The method for simulating a broadband signal affected by Doppler frequency in satellite communication according to claim 4, characterized in that: Also includes: storing the startup value and the operation value in a startup value cache queue and an operation value cache queue respectively; The start and stop of the second counter are controlled based on the remaining storage space size of the startup value cache queue and the operation value cache queue.

9. A broadband signal simulation system affected by Doppler frequency in satellite communication, characterized in that: It includes a signal front-end processing module, multiple filter groups, a Doppler calculation module, a sequential value module, a FIFO buffer and a reset item rotation multiplier; The input end of the signal front-end processing module is connected to the output end of the signal source; The output end of the signal front-end processing module is connected to the input end of the Doppler calculation module and the input ends of the multiple filter groups; The input end of the Doppler calculation module is also connected to the output end of the configuration module; The output end of the Doppler calculation module is connected to the input ends of the plurality of filter banks and the input end of the reset term rotation multiplier; The output ends of the plurality of filter groups are connected to the input end of the sequential value taking module; The sequential value taking module, the FIFO buffer and the reset item rotation multiplier are connected in sequence.

10. The broadband signal simulation system affected by Doppler frequency in satellite communication according to claim 9, characterized in that: The signal front-end processing module includes a signal receiver and a first counter, and the plurality of filter banks each include a first FIFO data buffer and a second FIFO data buffer; The input end of the signal receiver is connected to the output end of the signal source; The output end of the signal receiver is connected to the input end of the first counter and the input end of the first FIFO data buffer respectively; The output end of the first counter is connected to the input end of the second FIFO data buffer.

11. The broadband signal simulation system affected by Doppler frequency in satellite communication according to claim 9, characterized in that: The Doppler calculation module includes a second counter, a first operator, a start value cache queue, an operation value cache queue, a second operator, a direct digital frequency synthesizer and a controller, and the plurality of filter groups also include a comparator and a digital signal processor; The input end of the second counter is connected to the output end of the signal receiver, and the input end of the first operator is connected to the output end of the second counter and the output end of the configuration module; The output end of the first operator is connected to the input end of the startup value cache queue and the input end of the calculation value cache queue, and the input end of the controller is connected to the output end of the startup value cache queue and the output end of the calculation value cache queue; The input end of the comparator is connected to the output end of the controller and the output end of the second FIFO data buffer, and the controller is also connected to the second counter and the digital signal processor; The input end of the digital signal processor is connected to the output end of the comparator and the output end of the first FIFO data buffer, and the output end of the digital signal processor is connected to the input end of the sequential value module; The input end of the second operator is connected to the output end of the configuration module, and the output end of the second operator is connected to the input end of the direct digital frequency synthesizer; The output terminal of the direct digital frequency synthesizer is connected to the input terminal of the reset term rotation multiplier.

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