Channel dynamic simulation implementation method and system suitable for spread frequency measurement and control signal

Abstract

The application discloses a method for realizing dynamic simulation of a channel suitable for spread frequency measurement and control signals, which comprises the following steps: firstly, sampling a static radio frequency spread frequency signal, down-converting the signal to zero intermediate frequency and extracting a speed, so as to obtain a zero intermediate frequency spread frequency signal, and to make the carrier center frequency point Doppler and the spread frequency carrier Doppler accurately decoupled and separated; secondly, realizing dynamic simulation of the channel in two stages, the first stage adopts a variable fraction delay filter to realize time delay and dynamic simulation of the zero intermediate frequency spread frequency signal, and the second stage controls NCO to output a Doppler frequency offset signal corresponding to the radio frequency carrier center frequency point, and the outputs of the two stages are quadrature up-converted to obtain a baseband signal carrying a radio frequency dynamic; and finally, the dynamic radio frequency spread frequency signal is outputted through interpolation and up-conversion. The application realizes accurate simulation of the channel time delay and dynamic of the spread frequency signal by means of the channel simulation in stages and the variable fraction delay filter, and has the advantages of being irrelevant to the system of the sampled signal and not affecting the ranging and speed performance of the signal.

Description

Technical Field

[0001] This invention relates to a method and system for implementing channel dynamic simulation of spread frequency hopping measurement and control signals, belonging to the field of communication technology. Background Technology

[0002] Spread-frequency hopping transponders are a crucial component of satellite telemetry, tracking, and command (TT&C) systems, effectively enhancing the anti-interference capabilities of satellite TT&C radio frequency links. Ground-based test equipment for spread-frequency hopping transponders verifies their ranging, velocity, telemetry, and remote control functions and specifications on the ground. Since it's impossible to establish the actual dynamic environment of the TT&C channel during satellite operation on the ground, ground-based test equipment typically tests the performance of spread-frequency hopping transponders through channel dynamic simulation. In satellite TT&C systems, ground-based transponder test equipment generally couples TT&C signal generation with channel dynamic simulation. During TT&C signal generation, channel dynamics are simulated by changing the frequency control words of the NCO and carrier NCO. This method suffers from time delay, low dynamic simulation accuracy, and tight coupling between the implementation method and the satellite TT&C signal system. If this method is used to simulate the channel dynamics of spread frequency hopping signals, it is first necessary to control the NCO to generate the direct-sequence spreading code Doppler, the frequency hopping code Doppler, the frequency hopping interval Doppler, and the frequency hopping carrier Doppler. This makes the method of controlling the NCO extremely complex and cannot ensure the coherence of the code phase and carrier phase of the spread frequency hopping dynamic signal, thus affecting the ranging and velocity measurement performance of the signal. Secondly, it is impossible to achieve high-precision channel delay and dynamic simulation.

[0003] To address the needs of ground testing of spread frequency hopping transponders and the shortcomings of existing channel dynamic simulation methods, this invention proposes a channel dynamic simulation implementation method suitable for spread frequency hopping measurement and control signals. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a channel dynamic simulation method suitable for spread frequency hopping telemetry and control signals, so as to realize high-precision channel delay and dynamic simulation of satellite spread frequency hopping telemetry and control signals.

[0005] The technical solution of this invention is:

[0006] A method for dynamic channel simulation of spread frequency hopping measurement and control signals includes:

[0007] The sampled static radio frequency spread frequency hopping signal is downconverted to zero intermediate frequency and decimated to reduce speed, thus obtaining a zero intermediate frequency spread frequency hopping signal;

[0008] The channel dynamic simulation is implemented in two stages. The first stage uses a variable fractional delay filter to realize the delay and dynamic simulation of the zero intermediate frequency spread frequency hopping signal. The second stage controls the NCO to output the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier.

[0009] The zero-IF dynamic spread frequency hopping signal and the radio frequency carrier Doppler frequency offset signal of the two-stage output are orthogonally upconverted to complete the channel delay and dynamic simulation of the radio frequency spread frequency hopping signal, and the baseband signal carrying radio frequency dynamics is obtained.

[0010] Dynamic radio frequency spread-hopping signals are output through interpolation and up-conversion.

[0011] Furthermore, the step of downconverting the sampled static radio frequency spread frequency hopping signal to zero intermediate frequency and decimating it to obtain a zero intermediate frequency spread frequency hopping signal specifically includes the following steps:

[0012] (1.1) Obtain the initial distance between the star and the ground ,speed acceleration accelerometer and satellite signal radio frequency points Channel delay and dynamic parameters;

[0013] (1.2) Based on the initial distance between the star and the ground ,speed acceleration accelerometer The satellite baseband signal data buffer write address is calculated in real time. and read address The fractional delay coefficient of the variable fractional delay filter Initial phase word of radio frequency carrier Doppler frequency offset signal and frequency control word ;

[0014] (1.3) The static radio frequency spread frequency hopping signal is sampled, down-converted, filtered and decimated to obtain the zero intermediate frequency spread frequency hopping signal.

[0015] Furthermore, during real-time calculations in step (1.2), a set of control parameters is generated each cycle of the system's global clock:

[0016] The zero-IF spread frequency hopping signal is written to the cache RAM according to the data cache write address; assuming the system global clock period is... The time counter is , Each time passing one Increment by 1 to increase the data sampling buffer count. ,but Time data cache write address for:

[0017]

[0018] In the above formula, Represents the modulo function. Indicates the maximum storage address of the data cache RAM;

[0019] The program retrieves data from the cache RAM according to the data cache read address and uses it as the input signal for the variable decimal time delay filter. Real-time data cache read address for:

[0020]

[0021] In the above formula, Represents the speed of light. This represents the floor function. Indicates the result of displacement accumulation. Indicates the data sampling and reading count; fractional filter coefficients. μ : It can control the variable fractional delay filter to achieve a size of Fractional channel delay; The fractional filter coefficients of the time-variable fractional delay filter are:

[0022]

[0023] Initial phase word and frequency control word : The initial phase word of the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier at time 10:00 and frequency control word for:

[0024]

[0025] In the above formula, Indicates the system global clock frequency. The frequency representing the center point of the radio frequency carrier. This represents the rounding function. Indicates the number of bits used in the frequency control word quantization; The relative velocity between Earth and space, This indicates the initial phase of the Doppler frequency offset signal.

[0026] Furthermore, the channel dynamic simulation is implemented in two stages. The first stage uses a variable fractional delay filter to simulate the delay and dynamics of the zero intermediate frequency spread frequency hopping signal. The second stage controls the NCO to output the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier, specifically as follows:

[0027] (2.1) Spread the zero intermediate frequency frequency hopping signal of branch I. and Q branch zero intermediate frequency spread frequency hopping signal Write to the cache address Write to the data cache RAM;

[0028] (2.2) Read the address based on the calculated satellite baseband signal Read signal data from the data buffer RAM, if Increasing by 1 reads a signal data point and feeds it into the variable fractional time delay filter; if Increasing by 2 will read two signal data points and send them to the variable fractional time delay filter; if If the delay remains unchanged, the signal data with a variable decimal delay will be invalid; during the data buffering and reading process, channel delay changes with a duration that is an integer multiple of the system's global clock cycle are simulated.

[0029] (2.3) The variable fractional delay filter is based on the calculated fractional delay. The signal data read from the data buffer RAM is filtered to generate a baseband dynamic analog signal. and This enables accurate channel delay and dynamic simulation of zero-IF spread frequency hopping signals; among which, This is the initial channel delay;

[0030] (2.4) The initial phase word of the Doppler frequency offset signal corresponding to the calculated radio frequency carrier center frequency. and frequency control word Control the NCO to generate radio frequency carrier Doppler frequency offset signal and Complete the second-level channel dynamic simulation; among which, This indicates the Doppler frequency offset of the radio frequency carrier.

[0031] Furthermore, the output signal of the variable fractional delay filter... and Doppler frequency offset signal with the center frequency of the radio frequency carrier and Orthogonal upconversion is performed to generate a baseband signal that carries the time delay and dynamics of the radio frequency channel.

[0032] Furthermore, the baseband signal carrying radio frequency channel delay and dynamics is interpolated and filtered to improve the sampling rate, and then a dynamic radio frequency spread-hopping signal is generated after up-conversion and DAC conversion. .

[0033] Furthermore, this invention also proposes a channel dynamic simulation implementation system suitable for spread-hop measurement and control frequency signals, comprising:

[0034] Zero-IF spread-frequency hopping signal acquisition module: downconverts the sampled static radio frequency spread-frequency hopping signal to zero-IF and depresses it to obtain the zero-IF spread-frequency hopping signal;

[0035] Dynamic simulation module: The channel dynamic simulation is implemented in two stages. The first stage uses a variable fractional delay filter to realize the delay and dynamic simulation of the zero intermediate frequency spread frequency hopping signal. The second stage controls the NCO to output the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier.

[0036] Dynamic RF Spread Frequency Hopping Signal Acquisition Module: Performs orthogonal upconversion on the zero intermediate frequency dynamic spread frequency hopping signal and the RF carrier Doppler frequency offset signal from the two-stage output to complete the channel delay and dynamic simulation of the RF spread frequency hopping signal, thereby obtaining the baseband signal carrying RF dynamics; outputs the dynamic RF spread frequency hopping signal through interpolation and upconversion.

[0037] The advantages of this invention compared to the prior art are:

[0038] (1) This invention proposes a method for dynamic hierarchical channel simulation. First, the radio frequency spread frequency hopping signal is downconverted to a zero intermediate frequency spread frequency hopping signal, so that the Doppler of the carrier center frequency and the Doppler of the frequency hopping carrier are accurately decoupled and separated. Then, dynamic hierarchical channel simulation is performed. By utilizing the advantage of a variable fractional delay filter to achieve high-precision dynamic channel simulation that is independent of the sampling signal's mode, the channel delay and dynamics of the spread frequency hopping signal are accurately simulated, ensuring the coherence of the code phase of the spread frequency hopping dynamic signal and the phase of the frequency hopping carrier, without affecting the ranging and velocity measurement performance of the signal.

[0039] 2) This invention reduces the signal sampling rate by downconversion, decimation reduction and dynamic channel hierarchical simulation, thereby reducing the resource overhead when using variable fractional delay filters to implement channel simulation, and making it easier to implement large delay and high dynamic channel simulation.

[0040] 3) This invention can be flexibly implemented based on FPGA. It can be used to develop an independent channel simulator or as a software module embedded in the software of ground test equipment. Attached Figure Description

[0041] Figure 1. Overall block diagram of a channel dynamic simulation implementation method suitable for spread frequency hopping measurement and control signals;

[0042] Figure 2. Flowchart of the dynamic simulation control parameter calculation module;

[0043] Figure 3. Schematic diagram of variable fractional delay filter. Detailed Implementation

[0044] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0045] like Figure 1 As shown, this invention proposes a channel dynamic simulation implementation method suitable for spread frequency hopping measurement and control signals, comprising the following steps:

[0046] First, the static radio frequency spread frequency hopping signal is sampled, downconverted, and decimated to generate a zero intermediate frequency spread frequency hopping signal;

[0047] Then, based on the set channel delay and dynamic simulation parameters, the channel delay and dynamic changes are calculated in real time. Based on the data buffer-read mechanism and variable fractional delay filter, the channel delay and dynamic simulation of the zero intermediate frequency spread frequency hopping signal are realized. At the same time, the digital NCO is controlled to generate the Doppler frequency offset signal corresponding to the center frequency point of the radio frequency carrier.

[0048] Secondly, the channel delay and dynamic simulation of the radio frequency spread frequency hopping signal are completed by orthogonal upconversion of the zero intermediate frequency dynamic spread frequency hopping signal and the radio frequency carrier Doppler frequency offset signal;

[0049] Finally, the signal is interpolated to increase the sampling rate, and after digital up-conversion, it is output as a dynamic radio frequency spread-hopping signal via a DAC.

[0050] The method for dynamic channel simulation of spread frequency hopping measurement and control signals includes the following steps:

[0051] Step 1: Obtain the initial distance between the satellite and the ground ,speed acceleration accelerometer and satellite signal radio frequency points Channel delay and dynamic parameters.

[0052] Step 2: The dynamic simulation control parameter calculation module calculates the initial distance between the satellite and the ground. ,speed acceleration accelerometer The satellite baseband signal data buffer write address is calculated in real time. and read address The fractional delay coefficient of the variable fractional delay filter Initial phase word of radio frequency carrier Doppler frequency offset signal and frequency control word The dynamic simulation control parameter calculation module is the control center for real-time dynamic channel simulation. Driven by the system's global clock, it generates a set of parameters each cycle to control the execution of lower-level programs.

[0053] The flowchart of the dynamic simulation control parameter calculation module is as follows: Figure 2 As shown.

[0054] After the program starts running, it first checks the time counter. and displacement accumulation value Initialization is performed, where the time counter represents the change in relative motion time between the satellite and the ground / inter-satellite, incrementing by 1 after each global clock cycle, and the displacement accumulation value represents the change in relative distance between the satellite and the ground / inter-satellite. Then, the time counter and displacement accumulation value are updated in each cycle of the global clock. If the time counter is not greater than the simulation time threshold, the dynamic simulation control parameters are calculated in each cycle of the global clock; otherwise, the dynamic simulation ends.

[0055] The calculation steps for the above parameters are as follows:

[0056] `data_addr_in`: Under global clock drive, the zero-IF spread frequency hopping signal is written to the cache RAM according to the data buffer write address. Assume the system global clock period is... Data sampling cache count ,but Time data cache write address for:

[0057] (1)

[0058] In the above formula, Represents the modulo function. This indicates the maximum storage address of the data cache RAM.

[0059] data_addr_out: The program retrieves data from the cache RAM according to the data cache read address and uses it as the input signal for the variable decimal delay filter. Real-time data cache read address for:

[0060] (2)

[0061] In the above formula, Represents the speed of light. This represents the floor function. Indicates the result of displacement accumulation. This indicates the data sampling and reading count.

[0062] μ The fractional filter coefficients can control the size of the variable fractional delay filter. The fractional channel delay. The fractional filter coefficients of the time-variable fractional delay filter are:

[0063] (3)

[0064] frq_bias_phase and frq_bias_code: The initial phase word frq_bias_phase and frequency control word of the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier at time 10:00. for:

[0065] (4)

[0066] In the above formula, Indicates the system global clock frequency. The frequency representing the center point of the radio frequency carrier. This represents the rounding function. Indicates the number of bits used in the frequency control word quantization; Relative velocity between Earth and space This indicates the initial phase of the Doppler frequency offset signal.

[0067] Step 3: Sample, downconvert, filter, and decimate the static RF spread frequency hopping signal to obtain a zero intermediate frequency (IF) spread frequency hopping signal. Downconverting the static RF spread frequency hopping signal to obtain the IF spread frequency hopping signal aims to accurately decouple the Doppler of the carrier center frequency and the Doppler of the frequency hopping carrier, facilitating subsequent dynamic hierarchical channel simulation.

[0068] The purpose of decimating and slowing down the sampled signal is to reduce the sampling rate of the signal, thereby reducing the resource overhead when using a variable fractional delay filter to implement channel simulation, and making it easier to implement channel simulation with large delay and high dynamics.

[0069] A static radio frequency spread-hopping signal can be represented as:

[0070] (5)

[0071] In the formula, This indicates taking the real part of the signal. Indicates signal amplitude. Representing data information, Indicates direct-sequence pseudocode, Indicates the duration of a jump. express Frequency hopping frequency within, Indicates carrier phase, generally , For rectangular pulse functions:

[0072] (6)

[0073] This signal is processed by the working clock. = High-speed ADC sampling generates The sampled signal, under the condition that the Nyquist sampling theorem is satisfied, is then down-converted and... Extraction reduces the signal sampling rate to the FPGA global clock frequency, resulting in the I-branch zero-IF spread frequency hopping signal. and Q branch zero intermediate frequency spread frequency hopping signal :

[0074] (7)

[0075] Because a high sampling rate increases the resource overhead required for implementing the variable fractional delay filter in step six, the RF sampling signal is first down-converted to zero intermediate frequency before proceeding. Extraction reduces the operating clock frequency and data buffer requirements for channel simulation to their original levels. This not only reduces implementation resource overhead but also facilitates the simulation of channels with large latency and high dynamics. Furthermore, downconverting the RF sampling signal to zero intermediate frequency (IF) eliminates the influence of the RF carrier center frequency on the frequency hopping carrier frequency, allowing for precise decomposition of channel dynamics into two stages for simulation. The first stage simulates the channel latency and dynamics of the zero IF spread frequency hopping signal, while the second stage simulates the Doppler frequency offset of the RF carrier center frequency.

[0076] The first stage uses a variable fractional delay filter to simulate the time delay and dynamics of the zero-IF spread frequency hopping signal. The purpose is to utilize the advantage of the variable fractional delay filter to achieve high-precision channel dynamic simulation that is independent of the sampled signal's mode, thereby achieving accurate simulation of the channel delay and dynamics of the spread frequency hopping signal. This ensures the coherence of the code phase of the spread frequency hopping dynamic signal and the phase of the frequency hopping carrier, without affecting the signal's ranging and velocity measurement performance. The second stage controls the NCO to output the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier. By performing orthogonal up-conversion on the outputs of the two stages, a baseband signal carrying radio frequency dynamics is obtained.

[0077] Step 4: Spread the zero-IF frequency hopping signal of branch I. and Q branch zero intermediate frequency spread frequency hopping signal Write to the cache address Write it into the data cache RAM.

[0078] Step 5: Read the satellite baseband signal address calculated by the dynamic simulation control parameter calculation module. Read signal data from the data buffer RAM. If Increasing by 1 reads a signal data point and feeds it into the variable fractional time delay filter; if Increasing by 2 will read two signal data points and send them to the variable fractional time delay filter; if If the input signal data has a variable decimal delay, it becomes invalid. During data buffering and retrieval, channel delay variations with durations equal to integer multiples of the system's global clock cycle are simulated.

[0079] Step Six: The variable fractional delay filter calculates the fractional delay based on the dynamic analog control parameter calculation module. The signal data read from the data buffer RAM is filtered to generate a baseband dynamic analog signal. and This enables accurate channel delay and dynamic simulation of zero-IF spread frequency hopping signals. and Represented as:

[0080] (8)

[0081] In the formula, = , indicating the initial channel delay, Indicates a dynamic signal.

[0082] The variable fractional delay filter achieves channel delay and dynamic simulation by interpolating the sampled signal. The simulation accuracy depends only on the filter order and the quantization bit width of the fractional delay coefficients, and is independent of the signal's modulation scheme. Therefore, steps five and six achieve the time delay and dynamic simulation of the zero-IF spread frequency hopping signal, i.e., the first-stage channel dynamic simulation.

[0083] The variable fractional delay filter is implemented using the Farrow structure, and its principle is explained below:

[0084] The frequency response of an ideal variable fractional delay filter is:

[0085] (9)

[0086] The impact response corresponding to the above formula is:

[0087] (10)

[0088] You can see It is an infinitely long non-causal sequence that cannot be achieved. Therefore, we adopt... Step Polynomials are used to approximate the filter coefficients. :

[0089] (11)

[0090] The implementation of a variable fractional delay filter is as follows: Figure 3 As shown. The fractional delay coefficient of the Farrow polyphase filter. The changes are updated in each cycle of the global clock, while the structural coefficients... It remains unchanged. Therefore, during engineering implementation, It can be pre-calculated based on the Lagrange interpolation method to generate A file of FIR filter coefficients, then generate indivual The first-order FIR filter will... , The output of each filter and The results are multiplied and then summed to obtain the filter output.

[0091] Step 7: Calculate the initial phase word of the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier calculated by the dynamic simulation control parameter calculation module. and frequency control word Control the NCO to generate radio frequency carrier Doppler frequency offset signal and Complete the second-level channel dynamic simulation; among which, This indicates the Doppler frequency offset of the radio frequency carrier.

[0092] Step 8: Convert the output signal of the variable fractional delay filter. and Doppler frequency offset signal with the center frequency of the radio frequency carrier and Orthogonal upconversion is performed to generate a baseband signal that carries the time delay and dynamics of the radio frequency channel.

[0093] Step 9: After interpolating, filtering, up-converting, and DAC-converting the baseband signal carrying RF channel delay and dynamics, a dynamic RF spread frequency hopping signal is generated. :

[0094] (12)

[0095] This invention achieves high-precision dynamic channel simulation by using a variable fractional delay filter, which is independent of the sampled signal's mode. This enables accurate simulation of the channel delay and dynamics of spread frequency hopping signals, ensuring the coherence of the code phase and carrier phase of the dynamic spread frequency hopping signal without affecting the signal's ranging and velocity measurement performance. By down-converting, decimation, and dynamic hierarchical channel simulation, the sampling rate of the signal is reduced, lowering the resource overhead when using a variable fractional delay filter for channel simulation, and making it easier to achieve large delay and high dynamic channel simulation.

[0096] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for dynamic simulation of channel for spread spectrum TT&C signal, characterized in that include: The sampled static radio frequency spread frequency hopping signal is downconverted to zero intermediate frequency and decimated to reduce speed, thus obtaining a zero intermediate frequency spread frequency hopping signal; The channel dynamic simulation is implemented in two stages. The first stage uses a variable fractional delay filter to realize the delay and dynamic simulation of the zero intermediate frequency spread frequency hopping signal. The second stage controls the NCO to output the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier. The zero-IF dynamic spread frequency hopping signal and the radio frequency carrier Doppler frequency offset signal of the two-stage output are orthogonally upconverted to complete the channel delay and dynamic simulation of the radio frequency spread frequency hopping signal, and the baseband signal carrying radio frequency dynamics is obtained. Dynamic radio frequency spread hopping signal is output through interpolation and up-conversion; The process of downconverting the sampled static radio frequency spread frequency hopping signal to zero intermediate frequency and decimating it to obtain a zero intermediate frequency spread frequency hopping signal specifically includes the following steps: (1.1), acquiring initial satellite-ground distance velocity acceleration jerk and satellite signal radio frequency point channel delay and dynamic parameters; (1.2), according to the initial distance between satellite and ground , velocity , acceleration , jerk , real-time calculation of satellite baseband signal data cache write address and read address , fractional delay coefficient of variable fractional delay filter , initial phase word of radio frequency carrier Doppler frequency offset signal and frequency control word ; (1.3) The static radio frequency spread frequency hopping signal is sampled, down-converted, filtered and decimated to obtain the zero intermediate frequency spread frequency hopping signal; The channel dynamic simulation is implemented in two stages. The first stage uses a variable fractional delay filter to simulate the delay and dynamics of the zero intermediate frequency spread frequency hopping signal. The second stage controls the NCO to output the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier. Specifically: (2.1), the I branch zero intermediate frequency spread frequency hopping signal and Q branch zero intermediate frequency spread frequency hopping signal according to the cache write address write data into the cache RAM; (2.2) reading the satellite baseband signal according to the calculated address reading signal data from the data buffer RAM, if increasing 1, reading one signal data into the variable fractional delay filter; if increasing 2, reading two signal data into the variable fractional delay filter; if unchanged, the signal data into the variable fractional delay is invalid; the channel delay variation with the integer multiple of the system global clock period is simulated during the data buffering and reading process; (2.3), the variable fractional delay filter according to the calculated fractional delay fraction Filtering the signal data read from the data buffer RAM to generate a baseband dynamic analog signal And Realize the accurate channel delay and dynamic simulation of the zero intermediate frequency spread frequency hopping signal; wherein, The channel initial delay; (2.4) The initial phase word of the Doppler frequency offset signal corresponding to the calculated radio frequency carrier center frequency. and frequency control word Control the NCO to generate radio frequency carrier Doppler frequency offset signal and Complete the second-level channel dynamic simulation; among which, This indicates the Doppler frequency offset of the radio frequency carrier.

2. The channel dynamic simulation implementation method for spread-hop measurement and control frequency signals according to claim 1, characterized in that: During real-time calculations in step (1.2), a set of control parameters is generated each cycle of the system's global clock: The zero-IF spread frequency hopping signal is written into the cache RAM according to the data cache write address; Assume the system's global clock period is The time counter is , Each time passing one Increment by 1 to increase the data sampling buffer count. ,but Time data cache write address for: In the above formula, Represents the modulo function. Indicates the maximum storage address of the data cache RAM; The program retrieves data from the cache RAM according to the data cache read address and uses it as the input signal for the variable decimal time delay filter. Real-time data cache read address for: In the above formula, Represents the speed of light. This represents the floor function. Indicates the result of displacement accumulation. Indicates the data sampling and reading count; fractional filter coefficients. μ : It can control the variable fractional delay filter to achieve a size of Fractional channel delay; The fractional filter coefficients of the time-variable fractional delay filter are: Initial phase word and frequency control word : The initial phase word of the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier at time 10:00 and frequency control word for: In the above formula, Indicates the system global clock frequency. The frequency representing the center point of the radio frequency carrier. This represents the rounding function. Indicates the number of bits used in the frequency control word quantization; The relative velocity between Earth and space, This indicates the initial phase of the Doppler frequency offset signal.

3. The channel dynamic simulation implementation method for spread-hop measurement and control frequency signals according to claim 1, characterized in that: The output signal of the variable fractional delay filter and Doppler frequency offset signal with the center frequency of the radio frequency carrier and Orthogonal upconversion is performed to generate a baseband signal that carries the time delay and dynamics of the radio frequency channel.

4. The channel dynamic simulation implementation method for spread-hop measurement and control frequency signals according to claim 3, characterized in that: The sampling rate is improved by interpolating and filtering the baseband signal carrying radio frequency channel delay and dynamics, and then the signal is generated by up-conversion and DAC conversion to produce a dynamic radio frequency spread-hopping signal. .

5. A channel dynamic simulation implementation system suitable for spread-hop measurement and control frequency signals, characterized in that... include: Zero-IF spread-frequency hopping signal acquisition module: downconverts the sampled static radio frequency spread-frequency hopping signal to zero-IF and depresses it to obtain the zero-IF spread-frequency hopping signal; Dynamic simulation module: The channel dynamic simulation is implemented in two stages. The first stage uses a variable fractional delay filter to realize the delay and dynamic simulation of the zero intermediate frequency spread frequency hopping signal. The second stage controls the NCO to output the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier. Dynamic RF Spread Frequency Hopping Signal Acquisition Module: Performs orthogonal upconversion on the zero-IF dynamic spread frequency hopping signal and the RF carrier Doppler frequency offset signal from the two-stage output to complete the channel delay and dynamic simulation of the RF spread frequency hopping signal, thereby obtaining the baseband signal carrying RF dynamics; outputs the dynamic RF spread frequency hopping signal through interpolation and upconversion; The step of downconverting the sampled static radio frequency spread frequency hopping signal to zero intermediate frequency and decimating it to obtain a zero intermediate frequency spread frequency hopping signal specifically includes: (1.1) Obtain the initial distance between the star and the ground ,speed acceleration accelerometer and satellite signal radio frequency points Channel delay and dynamic parameters; (1.2) Based on the initial distance between the star and the ground ,speed acceleration accelerometer The satellite baseband signal data buffer write address is calculated in real time. and read address The fractional delay coefficient of the variable fractional delay filter Initial phase word of radio frequency carrier Doppler frequency offset signal and frequency control word ; (1.3) The static radio frequency spread frequency hopping signal is sampled, down-converted, filtered and decimated to obtain the zero intermediate frequency spread frequency hopping signal; The channel dynamic simulation is implemented in two stages. The first stage uses a variable fractional delay filter to simulate the delay and dynamics of the zero intermediate frequency spread frequency hopping signal. The second stage controls the NCO to output the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier. Specifically: (2.1) Spread the zero intermediate frequency frequency hopping signal of branch I. and Q branch zero intermediate frequency spread frequency hopping signal Write to the cache address Write to the data cache RAM; (2.2) Read the address based on the calculated satellite baseband signal Read signal data from the data buffer RAM; if Increasing by 1 reads a signal data point and feeds it into the variable fractional time delay filter; if Increasing by 2 will read two signal data points and send them to the variable fractional time delay filter; if If the input signal data has a variable decimal delay, it is invalid; during the data buffering and reading process, channel delay changes with a duration that is an integer multiple of the system's global clock cycle are simulated. (2.3) The variable fractional delay filter is based on the calculated fractional delay. The signal data read from the data buffer RAM is filtered to generate a baseband dynamic analog signal. and This enables accurate channel delay and dynamic simulation of zero-IF spread frequency hopping signals; among which, This is the initial channel delay; (2.4) The initial phase word of the Doppler frequency offset signal corresponding to the calculated radio frequency carrier center frequency. and frequency control word Control the NCO to generate radio frequency carrier Doppler frequency offset signal and Complete the second-level channel dynamic simulation; among which, This indicates the Doppler frequency offset of the radio frequency carrier.

6. The channel dynamic simulation implementation system for spread-hop measurement and control frequency signals according to claim 5, characterized in that: During real-time calculations in step (1.2), a set of control parameters is generated each cycle of the system's global clock: Under global clock conditions, the zero-IF spread frequency hopping signal is written into the cache RAM according to the data cache write address; Assume the system's global clock period is The time counter is , Each time passing one Increment by 1 to increase the data sampling buffer count. ,but Time data cache write address for: In the above formula, Represents the modulo function. Indicates the maximum storage address of the data cache RAM; The program retrieves data from the cache RAM according to the data cache read address and uses it as the input signal for the variable fractional delay filter. Real-time data cache read address for: In the above formula, Represents the speed of light. This represents the floor function. Indicates the result of displacement accumulation. Indicates the data sampling and reading count; Fractional filter coefficients μ : It can control the variable fractional delay filter to achieve a size of Fractional channel delay; The fractional filter coefficients of the time-variable fractional delay filter are: Initial phase word and frequency control word : The initial phase word of the Doppler frequency offset signal corresponding to the center frequency of the radio frequency carrier at time 10:00 and frequency control word for: In the above formula, Indicates the system global clock frequency. The frequency representing the center point of the radio frequency carrier. This represents the rounding function. Indicates the number of bits used in the frequency control word quantization; Relative velocity between Earth and space This indicates the initial phase of the Doppler frequency offset signal.

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