阅读说明：本技术 用于实时模拟高动态卫星信道多普勒特性的方法和系统 (Method and system for real-time simulation of high dynamic satellite channel Doppler characteristics ) 是由 李蓬蓬 黄新明 刘欢 刘文祥 李柏渝 牟卫华 钟水彬 王峰毅 肖峥 杜丹 于 2021-09-06 设计创作，主要内容包括：本发明提出一种用于实时模拟高动态卫星信道多普勒特性的方法和系统。通过提高中频采样信号的采样率,对中频采样信号进行预处理,以获取射频采样信号；基于射频采样信号的信号参数和多普勒动态参数,确定多普勒模拟动态时延；通过累加控制对多普勒模拟动态时延执行插值处理,以获取多普勒模拟高频度动态时延,多普勒模拟高频度动态时延以动态时延控制字的形式来表征；将动态时延控制字划分为整数部分的第一动态时延和小数部分的第二动态时延；将射频采样信号分别发送至数据缓存区和可变时延滤波器组,以获得经数据缓存区存储转发的第一输出信号和经可变时延滤波器组滤波的第二输出信号；整合第一输出信号与第二输出信号。(The invention provides a method and a system for simulating Doppler characteristics of a high dynamic satellite channel in real time. Preprocessing the intermediate frequency sampling signal by improving the sampling rate of the intermediate frequency sampling signal to obtain a radio frequency sampling signal; determining Doppler simulation dynamic time delay based on signal parameters and Doppler dynamic parameters of the radio frequency sampling signals; performing interpolation processing on the Doppler simulation dynamic time delay through accumulation control to obtain Doppler simulation high-frequency dynamic time delay, wherein the Doppler simulation high-frequency dynamic time delay is represented in a form of a dynamic time delay control word; dividing the dynamic time delay control word into a first dynamic time delay of an integer part and a second dynamic time delay of a decimal part; respectively sending the radio frequency sampling signal to a data cache region and a variable delay filter bank to obtain a first output signal stored and forwarded by the data cache region and a second output signal filtered by the variable delay filter bank; the first output signal and the second output signal are integrated.)

1. A method for simulating doppler characteristics of a high dynamic satellite channel in real time, the method comprising:

step S1, preprocessing the intermediate frequency sampling signal by increasing the sampling rate of the intermediate frequency sampling signal to obtain a radio frequency sampling signal;

step S2, determining a doppler analog dynamic time delay based on the signal parameter and the doppler dynamic parameter of the radio frequency sampling signal, wherein:

the signal parameters comprise initial carrier frequencies and initial phases of a plurality of radio frequency sampling signals; the Doppler dynamic parameters comprise Doppler frequency and Doppler frequency change rate;

step S3, utilizing a phase acceleration accumulator and a phase velocity accumulator to perform interpolation processing on the Doppler simulated dynamic time delay through accumulation control so as to obtain Doppler simulated high-frequency dynamic time delay, wherein the Doppler simulated high-frequency dynamic time delay is represented in the form of dynamic time delay control words;

step S4, dividing the dynamic delay control word into a first dynamic delay of an integer part and a second dynamic delay of a fractional part, where the first dynamic delay is implemented by store-and-forward of a data buffer, and the second dynamic delay is implemented by a variable delay filter bank based on a polyphase filter structure;

step S5, sending the radio frequency sampling signal to the data buffer area and the variable delay filter bank respectively, so as to obtain a first output signal stored and forwarded by the data buffer area and a second output signal filtered by the variable delay filter bank;

step S6, integrating the first output signal and the second output signal, wherein the integrated output signal represents the doppler characteristic of the high dynamic satellite channel.

2. The method according to claim 1, wherein the step S2 specifically includes:

step S2-1, calculating a dynamic carrier frequency of the radio frequency sampling signal based on the initial carrier frequency, the doppler frequency, and the doppler frequency change rate by using formula (1):

（1）

wherein the content of the first and second substances,fis representative of the dynamic carrier frequency(s),f ₀is representative of the initial carrier frequency of the carrier,f _d is representative of the doppler frequency of the signal,mthe time is represented by the time of day,representing the rate of change of the doppler frequency, representing a dot product;

step S2-2, characterizing the dynamic phase of the radio frequency sampled signal using equation (2):

（2）

wherein the content of the first and second substances,which is representative of the initial phase of the phase,representing based on said dynamic carrier frequencyfTo characterize the dynamic phase of the signal,the characterization is based on the Doppler simulated dynamic time delayThe dynamic phase characterized;

step S2-3, combining the formula (1) and the formula (2), solving the Doppler simulation dynamic time delay, as shown in formula (3):

（3）

and the frequency of the parameter of the Doppler analog dynamic time delay is in millisecond level.

3. The method according to claim 2, wherein in the step S3, the obtaining the doppler simulated high frequency dynamic delay specifically includes:

step S3-1, performing first accumulation control on the input amount of the doppler frequency change rate by using a sampling pulse, and sending a result of the first accumulation control to the phase acceleration accumulator;

step S3-2, performing second accumulation control on the output of the phase acceleration accumulator and the doppler frequency using a sampling pulse pair, and sending a result of the second accumulation control to the phase velocity accumulator;

step S3-3, adding the output of the phase velocity accumulator to the initial phase to obtain the doppler analog high frequency dynamic delay, and adding the doppler analog high frequency dynamic delay to a nominal frequency control word to obtain the dynamic delay control word;

the sampling pulse is an accumulation enable pulse, the Doppler frequency change rate is a first interpolation parameter, the Doppler frequency is a second interpolation parameter, and the initial phase is a third interpolation parameter.

4. The method according to claim 3, wherein in step S4, the polyphase filter structure of the variable delay filter bank comprises a plurality of polyphase branches with different phases, each of the polyphase branches comprises a bandpass filter and a variable delay filter, and the variable delay filter in each of the polyphase branches simulates the second dynamic delay.

5. The method according to claim 4, wherein in step S5, the data buffer stores the received RF sample signal and generates a first output signal with a first dynamic delay when forwarding the RF sample signal.

6. The method according to claim 5, wherein in step S5, the filtering results of each branch of the variable delay filter bank are weighted and summed to obtain a second output signal with a second dynamic delay.

7. The method according to claim 6, wherein in step S6, the first output signal and the second output signal are summed, and the summed signal is down-converted to obtain the output signal, wherein the output signal has real-time doppler characteristic.

8. A system for simulating doppler characteristics of a high dynamic satellite channel in real time, the system comprising:

the device comprises a first processing unit, a second processing unit and a third processing unit, wherein the first processing unit is configured to pre-process an intermediate frequency sampling signal by increasing the sampling rate of the intermediate frequency sampling signal to obtain a radio frequency sampling signal;

a second processing unit configured to determine a doppler simulated dynamic time delay based on the signal parameters and doppler dynamic parameters of the radio frequency sampled signal, wherein:

the signal parameters comprise initial carrier frequencies and initial phases of a plurality of radio frequency sampling signals; the Doppler dynamic parameters comprise Doppler frequency and Doppler frequency change rate;

a third processing unit configured to perform interpolation processing on the doppler simulated dynamic time delay through accumulation control by using a phase acceleration accumulator and a phase velocity accumulator to obtain a doppler simulated high frequency dynamic time delay, the doppler simulated high frequency dynamic time delay being characterized in the form of a dynamic time delay control word;

a fourth processing unit, configured to divide the dynamic delay control word into a first dynamic delay of an integer part and a second dynamic delay of a fractional part, where the first dynamic delay is implemented by store-and-forward of a data buffer, and the second dynamic delay is implemented by a variable delay filter bank based on a polyphase filter structure;

a fifth processing unit, configured to send the radio frequency sampling signal to the data buffer and the variable delay filter bank, respectively, so as to obtain a first output signal stored and forwarded by the data buffer and a second output signal filtered by the variable delay filter bank;

a sixth processing unit configured to integrate the first output signal with the second output signal, the integrated output signal characterizing the high dynamic satellite channel Doppler characteristics.

9. An electronic device, characterized in that the electronic device comprises a memory and a processor, the memory storing a computer program which, when executed by the processor, performs the steps of a method for real-time simulation of doppler characteristics of a high dynamic satellite channel according to any one of claims 1 to 7.

10. A computer readable storage medium, having stored thereon a computer program which, when being executed by a processor, carries out the steps of a method for simulating doppler characteristics of a high dynamic satellite channel in real time according to any one of claims 1 to 7.

Technical Field

The invention belongs to the technical field of satellites, and particularly relates to a method and a system for simulating Doppler characteristics of a high dynamic satellite channel in real time.

Background

The satellite channel simulator can simulate the signal propagation characteristics in real time and is indispensable equipment for ground docking test before satellite transmission. The satellite signal receiving system measures the distance between a satellite and a receiver by measuring the propagation delay of the signal, thereby performing positioning calculation. When relative speed exists between the receiver and the satellite, the relative speed is reflected on the signal as the Doppler effect of the signal, and the Doppler effect has a large influence on the propagation delay measurement of the signal.

Therefore, the realization of the high dynamic Doppler characteristic simulation of the signal has important significance for the simulation of the satellite channel. How to simulate the high dynamic doppler characteristics by using a satellite channel simulator so as to realize real-time doppler simulation is one of the technical problems which need to be solved urgently in the technical field of satellites.

Disclosure of Invention

In order to solve the above technical problems, the present invention provides a solution for simulating the doppler characteristic of a high dynamic satellite channel in real time.

The invention discloses a method for simulating Doppler characteristics of a high dynamic satellite channel in real time in a first aspect, which comprises the following steps:

step S1, preprocessing the intermediate frequency sampling signal by increasing the sampling rate of the intermediate frequency sampling signal to obtain a radio frequency sampling signal;

step S2, determining a doppler analog dynamic time delay based on the signal parameter and the doppler dynamic parameter of the radio frequency sampling signal, wherein: the signal parameters comprise initial carrier frequencies and initial phases of a plurality of radio frequency sampling signals; the Doppler dynamic parameters comprise Doppler frequency and Doppler frequency change rate;

step S3, utilizing a phase acceleration accumulator and a phase velocity accumulator to perform interpolation processing on the Doppler simulated dynamic time delay through accumulation control so as to obtain Doppler simulated high-frequency dynamic time delay, wherein the Doppler simulated high-frequency dynamic time delay is represented in the form of dynamic time delay control words;

step S4, dividing the dynamic delay control word into a first dynamic delay of an integer part and a second dynamic delay of a fractional part, where the first dynamic delay is implemented by store-and-forward of a data buffer, and the second dynamic delay is implemented by a variable delay filter bank based on a polyphase filter structure;

step S5, sending the radio frequency sampling signal to the data buffer area and the variable delay filter bank respectively, so as to obtain a first output signal stored and forwarded by the data buffer area and a second output signal filtered by the variable delay filter bank;

step S6, integrating the first output signal and the second output signal, wherein the integrated output signal represents the doppler characteristic of the high dynamic satellite channel.

According to the method of the first aspect of the present invention, the step S2 specifically includes:

step S2-1, calculating a dynamic carrier frequency of the radio frequency sampling signal based on the initial carrier frequency, the doppler frequency, and the doppler frequency change rate by using formula (1):

（1）

wherein the content of the first and second substances,fis representative of the dynamic carrier frequency(s),f ₀is representative of the initial carrier frequency of the carrier,f _d is representative of the doppler frequency of the signal,mthe time is represented by the time of day,representing the rate of change of the doppler frequency, representing a dot product;

step S2-2, characterizing the dynamic phase of the radio frequency sampled signal using equation (2):

（2）

wherein the content of the first and second substances,which is representative of the initial phase of the phase,representing based on said dynamic carrier frequencyfTo characterize the dynamic phase of the signal,the characterization is based on the Doppler simulated dynamic time delayThe dynamic phase characterized;

step S2-3, combining the formula (1) and the formula (2), solving the Doppler simulation dynamic time delay, as shown in formula (3):

（3）

and the frequency of the parameter of the Doppler analog dynamic time delay is in millisecond level.

According to the method of the first aspect of the present invention, in step S3, the acquiring the doppler simulated high frequency dynamic time delay specifically includes:

step S3-1, performing first accumulation control on the input amount of the doppler frequency change rate by using a sampling pulse, and sending a result of the first accumulation control to the phase acceleration accumulator;

step S3-2, performing second accumulation control on the output of the phase acceleration accumulator and the doppler frequency using a sampling pulse pair, and sending a result of the second accumulation control to the phase velocity accumulator;

step S3-3, adding the output of the phase velocity accumulator to the initial phase to obtain the doppler analog high frequency dynamic delay, and adding the doppler analog high frequency dynamic delay to a nominal frequency control word to obtain the dynamic delay control word;

the sampling pulse is an accumulation enable pulse, the Doppler frequency change rate is a first interpolation parameter, the Doppler frequency is a second interpolation parameter, and the initial phase is a third interpolation parameter.

According to the method of the first aspect of the present invention, in step S4, the polyphase filter structure of the variable delay filter bank includes a plurality of polyphase branches with different phases, each of the polyphase branches includes a bandpass filter and a variable delay filter, and the variable delay filter on each of the polyphase branches simulates the second dynamic delay.

According to the method of the first aspect of the present invention, in step S5, the data buffer stores the received rf sampling signal, and generates a first output signal with a first dynamic delay while forwarding the rf sampling signal.

According to the method of the first aspect of the present invention, in step S6, the first output signal and the second output signal are summed, and the summed signal is down-converted to obtain the output signal, where the output signal has a real-time doppler characteristic.

According to the method of the first aspect of the present invention, in step S6, the first output signal and the second output signal are summed, and the summed signal is down-converted to obtain the output signal, where the output signal has a real-time doppler characteristic.

In a second aspect, the present invention discloses a system for simulating the doppler characteristic of a high dynamic satellite channel in real time, wherein the system comprises:

the device comprises a first processing unit, a second processing unit and a third processing unit, wherein the first processing unit is configured to pre-process an intermediate frequency sampling signal by increasing the sampling rate of the intermediate frequency sampling signal to obtain a radio frequency sampling signal;

a second processing unit configured to determine a doppler simulated dynamic time delay based on the signal parameters and doppler dynamic parameters of the radio frequency sampled signal, wherein:

the signal parameters comprise initial carrier frequencies and initial phases of a plurality of radio frequency sampling signals; the Doppler dynamic parameters comprise Doppler frequency and Doppler frequency change rate;

a third processing unit configured to perform interpolation processing on the doppler simulated dynamic time delay through accumulation control by using a phase acceleration accumulator and a phase velocity accumulator to obtain a doppler simulated high frequency dynamic time delay, the doppler simulated high frequency dynamic time delay being characterized in the form of a dynamic time delay control word;

a fourth processing unit, configured to divide the dynamic delay control word into a first dynamic delay of an integer part and a second dynamic delay of a fractional part, where the first dynamic delay is implemented by store-and-forward of a data buffer, and the second dynamic delay is implemented by a variable delay filter bank based on a polyphase filter structure;

a fifth processing unit, configured to send the radio frequency sampling signal to the data buffer and the variable delay filter bank, respectively, so as to obtain a first output signal stored and forwarded by the data buffer and a second output signal filtered by the variable delay filter bank;

a sixth processing unit configured to integrate the first output signal with the second output signal, the integrated output signal characterizing the high dynamic satellite channel Doppler characteristics.

According to the system of the second aspect of the invention, the second processing unit is specifically configured to determine the doppler simulated dynamic time delay in the following manner:

calculating the dynamic carrier frequency of the radio frequency sampling signal by using a formula (1) based on the initial carrier frequency, the Doppler frequency and the Doppler frequency change rate:

（1）

wherein the content of the first and second substances,fis representative of the dynamic carrier frequency(s),f ₀is representative of the initial carrier frequency of the carrier,f _d is representative of the doppler frequency of the signal,mthe time is represented by the time of day,representing the rate of change of the doppler frequency, representing a dot product;

characterizing the dynamic phase of the radio frequency sampled signal using equation (2):

（2）

wherein the content of the first and second substances,which is representative of the initial phase of the phase,representing based on said dynamic carrier frequencyfTo characterize the dynamic phase of the signal,the characterization is based on the Doppler simulated dynamic time delayThe dynamic phase characterized;

combining the formula (1) and the formula (2), and solving the Doppler simulation dynamic time delay, as shown in formula (3):

（3）

and the frequency of the parameter of the Doppler analog dynamic time delay is in millisecond level.

According to the system of the second aspect of the present invention, the third processing unit is specifically configured to obtain the doppler simulated high frequency dynamic time delay by:

performing first accumulation control on the input quantity of the Doppler frequency change rate by using sampling pulses, and sending a result of the first accumulation control to the phase acceleration accumulator;

performing second accumulation control on the output of the phase acceleration accumulator and the Doppler frequency by using a sampling pulse pair, and sending a result of the second accumulation control to the phase velocity accumulator;

adding the output of the phase velocity accumulator to the initial phase to obtain the Doppler analog high frequency dynamic time delay, and adding the Doppler analog high frequency dynamic time delay to a nominal frequency control word to obtain the dynamic time delay control word;

the sampling pulse is an accumulation enable pulse, the Doppler frequency change rate is a first interpolation parameter, the Doppler frequency is a second interpolation parameter, and the initial phase is a third interpolation parameter.

According to the system of the second aspect of the present invention, the polyphase filter structure of the variable delay filter bank includes a plurality of polyphase branches having different phases, each of the polyphase branches includes a bandpass filter and a variable delay filter, and the variable delay filter of each of the polyphase branches simulates the second dynamic delay.

According to the system of the second aspect of the present invention, the data buffer stores the received rf sampling signal, and generates a first output signal with a first dynamic delay while forwarding the rf sampling signal.

According to the system of the second aspect of the invention, the fifth processing unit is specifically configured to: and performing weighted summation on the filtering results of each branch of the variable delay filter bank to obtain a second output signal with a second dynamic delay.

According to the system of the second aspect of the present invention, the sixth processing unit is specifically configured to: and summing the first output signal and the second output signal, and performing down-conversion processing on the summed signal to obtain the output signal, wherein the output signal has real-time Doppler characteristics.

A third aspect of the invention discloses an electronic device. The electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method for simulating the doppler characteristic of the high dynamic satellite channel in real time according to the first aspect of the present invention when executing the computer program.

A fourth aspect of the invention discloses a computer-readable storage medium. The computer readable storage medium has stored thereon a computer program which, when being executed by a processor, performs the steps of a method for simulating doppler characteristics of a high dynamic satellite channel in real time according to the first aspect of the present invention.

In conclusion, the technical scheme of the invention obtains the Doppler dynamic parameters with higher refresh rate through high-speed interpolation so as to meet the near real-time dynamic simulation requirement of the satellite channel; meanwhile, by using the variable delay filter based on the multiphase filter structure, the Doppler real-time simulation of the high dynamic satellite channel is realized with lower resource consumption and extremely small real-time parameter updating amount. The technical scheme is to equate the Doppler characteristics to the dynamic change of signal time delay and realize real-time Doppler simulation by real-time dynamic control of signal phase.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow chart of a method for real-time simulation of Doppler characteristics of a high dynamic satellite channel in accordance with an embodiment of the present invention;

FIG. 2 is a diagram illustrating interpolation of Doppler simulated dynamic time delays according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a variable delay filter bank based on a polyphase filter structure according to an embodiment of the present invention;

fig. 4 is a schematic diagram of the structure of the variable delay filter on each branch according to the embodiment of the present invention;

FIG. 5 is a block diagram of a system for real-time simulation of high dynamic satellite channel Doppler characteristics, in accordance with an embodiment of the present invention;

fig. 6 is a block diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention discloses a method for simulating Doppler characteristics of a high dynamic satellite channel in real time in a first aspect. FIG. 1 is a flow chart of a method for real-time simulation of Doppler characteristics of a high dynamic satellite channel in accordance with an embodiment of the present invention; as shown in fig. 1, the method includes:

step S1, preprocessing the intermediate frequency sampling signal by increasing the sampling rate of the intermediate frequency sampling signal to obtain a radio frequency sampling signal;

step S2, determining a doppler analog dynamic time delay based on the signal parameter and the doppler dynamic parameter of the radio frequency sampling signal, wherein: the signal parameters comprise initial carrier frequencies and initial phases of a plurality of radio frequency sampling signals; the Doppler dynamic parameters comprise Doppler frequency and Doppler frequency change rate;

step S3, utilizing a phase acceleration accumulator and a phase velocity accumulator to perform interpolation processing on the Doppler simulated dynamic time delay through accumulation control so as to obtain Doppler simulated high-frequency dynamic time delay, wherein the Doppler simulated high-frequency dynamic time delay is represented in the form of dynamic time delay control words;

step S4, dividing the dynamic delay control word into a first dynamic delay of an integer part and a second dynamic delay of a fractional part, where the first dynamic delay is implemented by store-and-forward of a data buffer, and the second dynamic delay is implemented by a variable delay filter bank based on a polyphase filter structure;

step S5, sending the radio frequency sampling signal to the data buffer area and the variable delay filter bank respectively, so as to obtain a first output signal stored and forwarded by the data buffer area and a second output signal filtered by the variable delay filter bank;

step S6, integrating the first output signal and the second output signal, wherein the integrated output signal represents the doppler characteristic of the high dynamic satellite channel.

In step S1, the intermediate frequency sampled signal is preprocessed by increasing the sampling rate of the intermediate frequency sampled signal to obtain a radio frequency sampled signal.

In some embodiments, the intermediate frequency sampled signal isS ₀(n) Carrying out up-conversion treatment to double the sampling rate of all frequency points of the intermediate frequency sampling signal, thereby obtaining a radio frequency sampling signalS(n)。

In step S2, a doppler simulated dynamic time delay is determined based on the signal parameters and doppler dynamic parameters of the radio frequency sampled signal, wherein: the signal parameters comprise initial carrier frequencies and initial phases of a plurality of radio frequency sampling signals; the Doppler dynamic parameters include Doppler frequency and Doppler frequency change rate.

In some embodiments, the step S2 specifically includes:

step S2-1, calculating a dynamic carrier frequency of the radio frequency sampling signal based on the initial carrier frequency, the doppler frequency, and the doppler frequency change rate by using formula (1):

（1）

wherein the content of the first and second substances,fis representative of the dynamic carrier frequency(s),f ₀is representative of the initial carrier frequency of the carrier,f _d is representative of the doppler frequency of the signal,mthe time is represented by the time of day,representing the rate of change of the doppler frequency, representing a dot product;

step S2-2, characterizing the dynamic phase of the radio frequency sampled signal using equation (2):

（2）

wherein the content of the first and second substances,which is representative of the initial phase of the phase,representing based on said dynamic carrier frequencyfTo characterize the dynamic phase of the signal,the characterization is based on the Doppler simulated dynamic time delayThe dynamic phase characterized;

step S2-3, combining the formula (1) and the formula (2), solving the Doppler simulation dynamic time delay, as shown in formula (3):

（3）

and the frequency of the parameter of the Doppler analog dynamic time delay is in millisecond level.

In step S3, interpolation processing is performed on the doppler simulated dynamic time delay through accumulation control using a phase acceleration accumulator and a phase velocity accumulator to obtain a doppler simulated high frequency dynamic time delay, which is characterized in the form of a dynamic time delay control word.

In some embodiments, in the step S3, the obtaining the doppler simulated high frequency dynamic time delay specifically includes:

step S3-1, performing first accumulation control on the input amount of the doppler frequency change rate by using a sampling pulse, and sending a result of the first accumulation control to the phase acceleration accumulator;

step S3-2, performing second accumulation control on the output of the phase acceleration accumulator and the doppler frequency using a sampling pulse pair, and sending a result of the second accumulation control to the phase velocity accumulator;

step S3-3, adding the output of the phase velocity accumulator to the initial phase to obtain the doppler analog high frequency dynamic delay, and adding the doppler analog high frequency dynamic delay to a nominal frequency control word to obtain the dynamic delay control word;

the sampling pulse is an accumulation enable pulse, the Doppler frequency change rate is a first interpolation parameter, the Doppler frequency is a second interpolation parameter, and the initial phase is a third interpolation parameter.

Specifically, as shown in fig. 2 (fig. 2 is a schematic diagram of performing interpolation processing on a doppler analog dynamic delay according to an embodiment of the present invention), en _ vel _ ch is an accumulation enable pulse (sampling pulse) for controlling an accumulation speed, and the higher the frequency of the accumulation enable pulse (sampling pulse), the faster the accumulation speed. Each interpolation parameter is updated in real time according to the frequency of the sampling pulseThe interpolation parameter 1 (first interpolation parameter) is the doppler frequency change rate in the entire interpolation interval, the interpolation parameter 2 (second interpolation parameter) is the doppler frequency at the interpolation time, and the interpolation parameter 3 (third interpolation parameter) is the initial phase at the interpolation time. And updating the Doppler simulated high-frequency dynamic time delay TW through each interpolation parameter, wherein the Doppler simulated high-frequency dynamic time delay TW is 0 when relative dynamics does not exist between the satellite and the signal receiver. A given nominal frequency control word TW₀And adding the Doppler analog high-frequency dynamic time delay TW to obtain a dynamic time delay control word T _ ctrl (n).

In step S4, the dynamic delay control word is divided into a first dynamic delay of an integer part and a second dynamic delay of a fractional part, where the first dynamic delay is implemented by store-and-forward of a data buffer, and the second dynamic delay is implemented by a variable delay filter bank based on a polyphase filter structure.

Specifically, the dynamic delay control word is represented by formula (4):

（4）

wherein the content of the first and second substances,is the first dynamic time delay of the integer part,a second dynamic delay which is a fractional part.

In some embodiments, the polyphase filter structure of the variable delay filter bank includes a plurality of polyphase branches having different phases, each of the polyphase branches includes a bandpass filter and a variable delay filter, and the variable delay filter on each of the polyphase branches simulates the second dynamic delay.

Specifically, as shown in fig. 3 (fig. 3 is a schematic structural diagram of a variable delay filter bank based on a polyphase filter structure according to an embodiment of the present invention), polyphase filtering may decompose a system function of a digital filter into a plurality of polyphase branches (branch 0 and branch 1) with different phases according to phases (by uniform division), and filter a radio frequency sampling signal on each branch, so that a plurality of filters with lower orders (BPF is a bandpass filter and VFD is a variable delay recorder) may be used to implement a filter with a higher order originally, and a data rate and an effect of a signal in a processing process are guaranteed to be unchanged under a condition of low resource consumption.

In step S5, the rf sampling signals are respectively sent to the data buffer and the variable delay filter bank, so as to obtain a first output signal stored and forwarded by the data buffer and a second output signal filtered by the variable delay filter bank.

In some embodiments, in step S5, the data buffer stores the received rf sampling signal and generates a first output signal with a first dynamic delay while forwarding the rf sampling signal.

Specifically, for the delay design of the first dynamic delay of the integer part, the radio frequency sampling signal is stored in a data buffer area and is forwarded after the integer delay; first output signalS _d (n) Is shown in equation (5):

（5）

in some embodiments, in the step S5, the filtering results on each branch of the variable delay filter bank are weighted and summed to obtain a second output signal with a second dynamic delay.

Specifically, as shown in fig. 4 (fig. 4 is a schematic structural diagram of the variable delay filter on each branch according to the embodiment of the present invention), the output signals of the variable delay filter bank are showny(n)Second dynamic delay which can be fractionalWeighting coefficients for filters on N +1 branchesPerforming real-time update on the input signalx(n)Expressed by a weighted sum, whereiniWhen 0 is taken, the filter coefficient on the branch is constant, i.e. the amount of non-dynamic change. Thereby obtaining a second output signalS _s (n) Is shown in equation (6):

（6）

therefore, the variable time delay can be controlled by updating the first dynamic time delay and the second dynamic time delay, and the coefficient of the variable time delay filter bank is updated in real time according to the required time delay, so that the Doppler characteristic can still be simulated with high precision under the condition of high dynamic Doppler change.

In step S6, the first output signal and the second output signal are integrated, and the integrated output signal is characterized by the doppler characteristic of the high dynamic satellite channel.

In some embodiments, the first output signal and the second output signal are summed and the summed signal is down-converted to obtain the output signal, which has real-time doppler characteristics.

The summed signalIs shown in equation (7):

（7）

for summed signal (radio frequency signal)Performing digital down-conversion to obtain intermediate frequency signal as having real-time DopplerA characteristic output signal.

In conclusion, the technical scheme of the invention obtains the Doppler dynamic parameters with higher refresh rate through high-speed interpolation so as to meet the near real-time dynamic simulation requirement of the satellite channel; meanwhile, by using the variable delay filter based on the multiphase filter structure, the Doppler real-time simulation of the high dynamic satellite channel is realized with lower resource consumption and extremely small real-time parameter updating amount. The technical scheme is to equate the Doppler characteristics to the dynamic change of signal time delay and realize real-time Doppler simulation by real-time dynamic control of signal phase.

In a second aspect, the invention discloses a system for simulating Doppler characteristics of a high dynamic satellite channel in real time. FIG. 5 is a block diagram of a system for real-time simulation of high dynamic satellite channel Doppler characteristics, in accordance with an embodiment of the present invention; as shown in fig. 5, the system 500 includes:

a first processing unit 501 configured to pre-process the intermediate frequency sampling signal by increasing a sampling rate of the intermediate frequency sampling signal to obtain a radio frequency sampling signal;

a second processing unit 502 configured to determine a doppler simulated dynamic time delay based on the signal parameters and doppler dynamic parameters of the radio frequency sampled signal, wherein:

the signal parameters comprise initial carrier frequencies and initial phases of a plurality of radio frequency sampling signals; the Doppler dynamic parameters comprise Doppler frequency and Doppler frequency change rate;

a third processing unit 503, configured to perform interpolation processing on the doppler simulated dynamic time delay through accumulation control by using a phase acceleration accumulator and a phase velocity accumulator to obtain a doppler simulated high frequency dynamic time delay, which is characterized in the form of a dynamic time delay control word;

a fourth processing unit 504, configured to divide the dynamic delay control word into a first dynamic delay of an integer part and a second dynamic delay of a fractional part, where the first dynamic delay is implemented by store-and-forward of a data buffer, and the second dynamic delay is implemented by a variable delay filter bank based on a polyphase filter structure;

a fifth processing unit 505, configured to send the radio frequency sampling signal to the data buffer and the variable delay filter bank, respectively, so as to obtain a first output signal stored and forwarded by the data buffer and a second output signal filtered by the variable delay filter bank;

a sixth processing unit 506 configured to integrate the first output signal with the second output signal, the integrated output signal characterizing the high dynamic satellite channel doppler characteristic.

In the system according to the second aspect of the present invention, the second processing unit 502 is specifically configured to determine the doppler simulated dynamic time delay by:

calculating the dynamic carrier frequency of the radio frequency sampling signal by using a formula (1) based on the initial carrier frequency, the Doppler frequency and the Doppler frequency change rate:

（1）

wherein the content of the first and second substances,fis representative of the dynamic carrier frequency(s),f ₀is representative of the initial carrier frequency of the carrier,f _d is representative of the doppler frequency of the signal,mthe time is represented by the time of day,representing the rate of change of the doppler frequency, representing a dot product;

characterizing the dynamic phase of the radio frequency sampled signal using equation (2):

（2）

wherein the content of the first and second substances,which is representative of the initial phase of the phase,representing based on said dynamic carrier frequencyfTo characterize the dynamic phase of the signal,the characterization is based on the Doppler simulated dynamic time delayThe dynamic phase characterized;

combining the formula (1) and the formula (2), and solving the Doppler simulation dynamic time delay, as shown in formula (3):

（3）

and the frequency of the parameter of the Doppler analog dynamic time delay is in millisecond level.

According to the system of the second aspect of the present invention, the third processing unit 503 is specifically configured to obtain the doppler simulated high frequency dynamic delay by:

performing first accumulation control on the input quantity of the Doppler frequency change rate by using sampling pulses, and sending a result of the first accumulation control to the phase acceleration accumulator;

performing second accumulation control on the output of the phase acceleration accumulator and the Doppler frequency by using a sampling pulse pair, and sending a result of the second accumulation control to the phase velocity accumulator;

adding the output of the phase velocity accumulator to the initial phase to obtain the Doppler analog high frequency dynamic time delay, and adding the Doppler analog high frequency dynamic time delay to a nominal frequency control word to obtain the dynamic time delay control word;

the sampling pulse is an accumulation enable pulse, the Doppler frequency change rate is a first interpolation parameter, the Doppler frequency is a second interpolation parameter, and the initial phase is a third interpolation parameter.

According to the system of the second aspect of the present invention, the polyphase filter structure of the variable delay filter bank includes a plurality of polyphase branches having different phases, each of the polyphase branches includes a bandpass filter and a variable delay filter, and the variable delay filter of each of the polyphase branches simulates the second dynamic delay.

According to the system of the second aspect of the present invention, the data buffer stores the received rf sampling signal, and generates a first output signal with a first dynamic delay while forwarding the rf sampling signal.

According to the system of the second aspect of the present invention, the fifth processing unit 505 is specifically configured to: and performing weighted summation on the filtering results of each branch of the variable delay filter bank to obtain a second output signal with a second dynamic delay.

According to the system of the second aspect of the present invention, the sixth processing unit 506 is specifically configured to: and summing the first output signal and the second output signal, and performing down-conversion processing on the summed signal to obtain the output signal, wherein the output signal has real-time Doppler characteristics.

A third aspect of the invention discloses an electronic device. The electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method for simulating the doppler characteristic of the high dynamic satellite channel in real time according to the first aspect of the present invention when executing the computer program.

FIG. 6 is a block diagram of an electronic device according to an embodiment of the present invention; as shown in fig. 6, the electronic apparatus includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Wherein the processor of the electronic device is configured to provide computing and control capabilities. The memory of the electronic equipment comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The communication interface of the electronic device is used for carrying out wired or wireless communication with an external terminal, and the wireless communication can be realized through WIFI, an operator network, Near Field Communication (NFC) or other technologies. The display screen of the electronic equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the electronic equipment can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on the shell of the electronic equipment, an external keyboard, a touch pad or a mouse and the like.

It will be understood by those skilled in the art that the structure shown in fig. 6 is only a partial block diagram related to the technical solution of the present disclosure, and does not constitute a limitation of the electronic device to which the solution of the present application is applied, and a specific electronic device may include more or less components than those shown in the drawings, or combine some components, or have a different arrangement of components.

A fourth aspect of the invention discloses a computer-readable storage medium. The computer readable storage medium has stored thereon a computer program which, when being executed by a processor, performs the steps of a method for simulating doppler characteristics of a high dynamic satellite channel in real time according to the first aspect of the present invention.

In conclusion, the technical scheme of the invention obtains the Doppler dynamic parameters with higher refresh rate through high-speed interpolation so as to meet the near real-time dynamic simulation requirement of the satellite channel; meanwhile, by using the variable delay filter based on the multiphase filter structure, the Doppler real-time simulation of the high dynamic satellite channel is realized with lower resource consumption and extremely small real-time parameter updating amount. The technical scheme is to equate the Doppler characteristics to the dynamic change of signal time delay and realize real-time Doppler simulation by real-time dynamic control of signal phase.

It should be noted that the technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, however, as long as there is no contradiction between the combinations of the technical features, the scope of the present description should be considered. The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.