A method and system for controlling the time delay stability of a satellite navigation signal

Abstract

The application discloses a satellite navigation signal time delay stability control method and system, and the system comprises a reference time-frequency unit, a navigation signal generation unit, a navigation signal broadcasting system, a load management unit, a switch matrix, a navigation signal receiving unit and a constant temperature control unit; by establishing high-stable-state navigation signal receiving capability in the satellite load, real-time measurement of the time delay of the navigation signal is realized, and closed-loop time delay adjustment is formed with the navigation signal generation, so that the control of the navigation signal time delay stability is achieved.

Description

Technical Field

[0001] This invention relates to a method and system for controlling the time delay stability of satellite navigation signals, belonging to the field of satellite navigation signal generation technology. Background Technology

[0002] The stability of navigation signal delay is an important characteristic affecting high-precision navigation services, which is mainly manifested in two aspects: system characteristics and random characteristics.

[0003] The main characteristic of the system is the deviation in navigation signal time delay caused by temperature factors affecting the payload that generates the navigation signal. Limited by the time delay stability of the components themselves, the time delay stability of a typical navigation signal processing payload is approximately 20 ps / ℃ without temperature compensation control.

[0004] Traditionally, system delay variations caused by temperature changes are compensated for by accurately measuring the temperature-delay relationship of the payload generating navigation signals. This traditional approach requires temperature control of all payloads involved in navigation signal generation, and the payloads themselves must be designed with high-resolution temperature measurement capabilities to accurately determine the temperature-delay correlation for compensation. However, in actual payload development, it has been found that the temperature-delay correlation varies depending on the rate of temperature change, making it difficult to fit an accurate temperature-delay curve using only one or a few sample data points. Clearly, this traditional method imposes more constraints on payload design and is less conducive to future mass production of payloads.

[0005] The randomness is mainly manifested in the fact that the payload that generates navigation signals may have uncertainties in the phase or timing of signal generation due to the constraints of the signal generation phase, resulting in an unstable navigation signal delay and thus an abnormal uncertainty in the broadcast delay of the navigation signal.

[0006] For the random characteristics of time delay in payload design, the traditional method is to use a reference phase marker to establish a fixed start time for signal processing, thereby ensuring consistency in power-on, reset, and other states. For example, in the design of navigation signal generation using FPGA, establishing a fixed phase relationship between the navigation signal generation clock and the system synchronization marker 1PPS signal requires ensuring that the signal generation clock and the 1PPS signal can meet the timing constraints of establishment and hold, and that metastability does not occur. That is, the signal generation clock in the FPGA can stably and accurately sample the 1PPS signal and determine the rising edge as the fixed phase moment, thereby achieving a fixed time delay state for navigation signal generation in power-on, reset, and other states. However, as the frequency of the navigation signal generation clock increases, the timing margin for establishment and hold between these signals becomes smaller and smaller, making it very difficult to guarantee the time delay uncertainty requirements of the navigation signal, especially when accompanied by changes in external temperature, FPGA design version, and other conditions, making it impossible to guarantee the time delay stability of the navigation signal in power-on, reset, and other states.

[0007] Therefore, in order to meet the higher precision service requirements of future navigation satellite systems, it is necessary to carry out more effective design guarantees for the time delay stability of navigation signals. Summary of the Invention

[0008] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a satellite navigation signal delay stability control method and system. By establishing a highly stable navigation signal receiving capability within the satellite payload, the delay of the navigation signal can be measured in real time, and a closed-loop delay adjustment can be formed with the navigation signal generation, thereby achieving control over the delay stability of the navigation signal.

[0009] The technical solution of this invention is:

[0010] This invention discloses a method for controlling the time delay stability of satellite navigation signals, comprising:

[0011] S1. Based on the preset temperature control range, calibrate the relationship between temperature and time delay to obtain the correspondence between temperature and time delay;

[0012] S2. Select the monitoring point for the time delay to be measured in the satellite navigation system;

[0013] S3. Measure the time delay of the monitoring point and determine the time delay measurement value of the current state;

[0014] S4. Set the current delay measurement value as the target for satellite navigation signal delay control;

[0015] S5. Based on the satellite navigation signal delay control target, set the target delay value and target error control range for the satellite navigation signal;

[0016] S6. Perform real-time signal reception, time delay measurement, and temperature measurement. Based on the temperature-time delay correspondence, compensate for the time delay measurement results to obtain the time delay value.

[0017] S7. The difference between the delay value and the target delay value is calculated to obtain the difference result;

[0018] S8. Based on the cross-difference results and the target error control range, obtain the effective time delay adjustment amount;

[0019] S9. Decompose the effective delay adjustment amount to obtain integer delay adjustment precision and fractional delay adjustment precision;

[0020] S10. Adjust the delay of the navigation signal according to the integer delay adjustment precision and the fractional delay adjustment precision;

[0021] S11. When the time delay of the measured signal changes, repeat steps S3 to S10 above to always keep the time delay of the navigation signal within the set control target range and maintain the stability of the navigation signal's time delay.

[0022] Furthermore, in the above control method, the step of calibrating the temperature-time delay relationship of the navigation signal receiving unit according to a preset temperature control range to obtain the temperature-time delay correspondence is specifically as follows:

[0023] Within the temperature control range, the navigation signal receiving unit measures and statistically analyzes the time delay measurement error and the time delay average value for each X degrees Celsius segment according to temperature points.

[0024] Less than the error precision The time delay measurement error is averaged to obtain the mean time delay;

[0025] Based on the average time delay, establish a correlation between temperature and time delay.

[0026] Furthermore, in the above control method, the error accuracy specifically refers to:

[0027]

[0028] in, To ensure measurement error accuracy, For RF front-end bandwidth, For pseudocode symbol width, For loop noise bandwidth, For the relevant spacing, For the relevant integration time, This represents the signal-to-noise ratio.

[0029] Furthermore, in the above control method, the specific method for obtaining the effective time delay adjustment amount based on the cross-difference result and the target error control range is as follows:

[0030] judge If the condition is not met, calculate the valid delay adjustment amount; if it is met, retain the previous delay adjustment amount as the valid delay adjustment amount. The actual results of the current measurement, For the set target delay value, The error range of the control target delay is set.

[0031] Furthermore, in the above control method, the calculation of the effective time delay adjustment amount specifically includes:

[0032]

[0033] in, This is the total adjustment delay amount. The actual results of the current measurement, For the set target delay value, The error range of the control target delay is set.

[0034] Furthermore, in the above control method, the step of decomposing the effective time delay adjustment amount to obtain the required time delay parameters specifically involves:

[0035]

[0036] in, is the total adjusted delay amount, n is the integer delay adjustment parameter, m is the fractional delay adjustment parameter, and T is the integer delay adjustment precision. Adjust the precision for decimal delay.

[0037] This invention discloses a satellite navigation signal delay stability control system, comprising a reference time-frequency unit, a navigation signal generation unit, a navigation signal broadcasting system, a payload management unit, a switching matrix, a navigation signal receiving unit, and a constant temperature control unit; wherein,

[0038] The reference time-frequency unit generates the system synchronization time-frequency signal, which is used as a phase reference for time delay measurement and as a clock signal of the same frequency required for navigation signal generation;

[0039] The navigation signal generation unit adjusts the time delay of the navigation signal based on the time difference result of the load management unit, generates a medium frequency or radio frequency low power navigation signal, and sends it to the navigation signal broadcasting system and the switching matrix.

[0040] The navigation signal broadcasting system filters, converts, amplifies, and splits the intermediate frequency or radio frequency low-power navigation signal sent by the navigation signal generation unit to generate a transmitted navigation signal, which is then sent to the antenna.

[0041] The antenna transmits navigation signals in the airspace;

[0042] The navigation signal receiving unit captures, tracks, and measures the time delay of intermediate frequency or radio frequency navigation signals generated by different monitoring points forwarded by the switch matrix, and sends the time delay measurement results to the load management unit.

[0043] The switching matrix, based on the channel switching command sent by the load management unit, selects the intermediate frequency or radio frequency low-power navigation signal generated by the corresponding navigation signal generation unit as the output signal and forwards it to the navigation signal receiving unit.

[0044] The load management unit statistically analyzes the time delay measurement results sent by the navigation signal receiving unit, compares them with the predetermined time delay parameters, generates a time difference result, and sends it to the navigation signal generation unit.

[0045] The temperature control unit controls the ambient temperature of the navigation signal receiving unit, ensuring that the navigation signal receiving unit operates in an environment with constant or minimal temperature variation.

[0046] Furthermore, in the aforementioned control system, the navigation signal generation unit includes an integer delay module, a fractional delay module, and a register; wherein, the integer delay module reads integer delay parameters from the register, applies a digital domain navigation signal delay method to apply integer delay to the navigation information, and generates integer delay information; the fractional delay module reads fractional delay parameters from the register, applies a digital filter delay method to apply fractional delay to the integer delay information, and generates delay-adjusted navigation information.

[0047] Furthermore, in the above control system, the digital domain navigation signal delay method specifically involves delaying the signal by controlling the delay number of clock cycles generated by the navigation signal, with the delay adjustment accuracy being the clock period T generated by the navigation signal.

[0048] Furthermore, in the aforementioned control system, the digital filter delay method specifically involves adjusting the delay filter parameters. The fractional delay is adjusted; the impulse response of the delay filter is:

[0049]

[0050] in, For frequency, This is the decimal time delay adjustment parameter, where n is the time.

[0051] The advantages of this invention over the prior art are as follows:

[0052] (1) Traditional time delay stability control only compensates for the time delay and temperature in the digital domain generation part of the navigation signal generation, which has a limited control range and cannot cover all payload devices inside the satellite payload used to generate navigation signals. The present invention has a comprehensive and flexible control range for navigation signal time delay, which can effectively compensate for the impact of time delay changes of all payload devices inside the satellite payload on navigation signal time delay, improving it by at least one order of magnitude and effectively ensuring the stability of user services;

[0053] (2) The stability accuracy of traditional time delay is limited by the accuracy and precision of temperature measurement, and the relationship between temperature and time delay changes is not absolutely linear, resulting in poor control accuracy and high implementation difficulty. This invention achieves high control accuracy of navigation signal time delay through high-precision navigation signal measurement and time delay parameter control, avoiding the direct relationship between temperature and time delay during navigation signal generation, and can more accurately and effectively compensate for the time delay changes caused by environmental factors such as temperature on navigation signals;

[0054] (3) This invention is highly adaptable to the problem of navigation signal delay stability and can effectively solve the control of navigation signal transmission delay uncertainty caused by multiple development machines, resets, etc. It avoids the implementation risk of navigation signal generation under future high-speed clock conditions that may be caused by the traditional method of determining the initial phase through synchronization time mark, and greatly reduces the complexity of the payload equipment to implement this feature. Attached Figure Description

[0055] Figure 1 This is a flowchart of the method of the present invention;

[0056] Figure 2 This is a block diagram illustrating the principle of a satellite navigation signal delay stability control method according to the present invention.

[0057] Figure 3 This is a graph showing the time delay stability test results of the present invention. Detailed Implementation

[0058] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0059] like Figure 2 As shown, this invention discloses a satellite navigation signal delay stability control system. By establishing a highly stable navigation signal receiving capability within the satellite payload, the system enables real-time measurement of the navigation signal delay and forms a closed-loop delay adjustment with the navigation signal generation, thereby achieving control over the navigation signal delay stability.

[0060] It includes a reference time and frequency unit, a navigation signal generation unit, a navigation signal broadcasting system, a load management unit, a switch matrix, a navigation signal receiving unit, and its constant temperature environment.

[0061] The reference time and frequency unit generates the system synchronization time and frequency signal, which is used as a phase reference for time delay measurement and as a clock signal of the same frequency required for navigation signal generation.

[0062] The navigation signal generation unit performs the function of generating navigation signals in the digital domain and producing low-power intermediate frequency or radio frequency navigation signals through digital-to-analog conversion;

[0063] The navigation signal broadcasting system performs functions such as filtering, frequency conversion, power amplification, and splitting of intermediate frequency or radio frequency low-power navigation signals in the analog domain;

[0064] The antenna performs functions such as transmitting navigation signals in the airspace;

[0065] The navigation signal receiving unit performs the functions of capturing, tracking, and measuring the time delay of intermediate frequency or radio frequency navigation signals generated from different monitoring points.

[0066] Thermostatic control is the control of the ambient temperature of the navigation signal receiving unit, with the aim of making the navigation signal receiving unit work in a constant or very small temperature change environment; the temperature change range is -5℃ to 5℃.

[0067] The switch matrix selects the navigation signal generated by the corresponding navigation signal generation unit as the output signal according to the channel switching command.

[0068] The load management unit performs statistical analysis of the delay measurement results of the navigation signal receiving unit and the difference between the results and the predetermined delay parameters, thereby controlling the precise adjustment of the navigation signal delay by adjusting the relevant delay parameters in the navigation signal generation design.

[0069] like Figure 1 As shown, the present invention provides a satellite navigation signal delay stability control method, comprising the following steps:

[0070] Step 1: The satellite navigation signal generation design has formed a high-precision time delay adjustment capability with both integer and decimal values;

[0071] The integer delay adopts the digital domain navigation signal delay method, that is, the delay is achieved by controlling the delay number of clock cycles generated by the navigation signal. The delay adjustment accuracy is the clock period T generated by the navigation signal, and the delay adjustment amount can be designed according to the development requirements.

[0072] The fractional time delay is achieved using a digital filter delay method. An ideal low-pass digital filter should have the following frequency characteristics:

[0073]

[0074] The impulse response for time delay adjustment is obtained through calculation. If the time delay is 0, it is defined as zero. In this case, the filter impulse response is:

[0075]

[0076] Filter pair The resolution is very high, and the fractional delay is achieved by adjusting the delay filter parameters to form a [resolution]. Latency adjustment capability Factors limiting the performance of the results include: sampling frequency, Quantification and truncation.

[0077] In this embodiment, a 122.76MHz clock is used for navigation signal generation. The integer adjustment precision is one 122.76MHz clock cycle, i.e., T = 1 / 122.76MHz. The fractional adjustment precision is achieved by designing a delay filter to approximately divide T into N parts. Delay filters are typically implemented using FIR filters.

[0078] Step 2: Perform high-precision temperature and time delay relationship calibration on the navigation signal receiving unit within a preset temperature control range;

[0079] The navigation signal receiving unit uses a delay phase-locked loop for pseudocode measurement, and its main measurement error is caused by code phase jitter.

[0080]

[0081] in, For RF front-end bandwidth, For pseudocode symbol width, For loop noise bandwidth, For the relevant spacing, For the relevant integration time.

[0082] Based on the constant temperature control range (usually set to a narrow temperature change range and a small temperature change rate according to the system's time delay stability requirements), with To improve measurement accuracy, the systematic error relationship between the temperature and time delay of the navigation signal receiving unit was calibrated, and this relationship was incorporated into the calculation of the time delay measurement results of the navigation signal receiving unit, ensuring that the compensated measurement results conform to the measurement error. The systematic delay measurement deviation is much smaller than the delay stability performance required by the system.

[0083] In this embodiment, the system provides a constant temperature control range of 20±5℃ and a temperature change of <±0.5℃ / min. Under these conditions, or even wider temperature ranges, the navigation signal receiving unit measures and statistically calculates the measurement accuracy and average time delay at 1℃ intervals. The statistical time delay measurement error meets the following requirements. Under these conditions, the average time delay of each temperature measurement point is used as a reference to establish the correspondence between time delay and temperature. The difference between the average time delay under 20℃ conditions is taken as the systematic error introduced by temperature conditions, and its compensation is designed into the pseudocode time delay measurement results of the navigation signal receiving unit.

[0084] Step 3: The load management unit controls the switch matrix through commands or other means to select the monitoring point of the time delay to be measured in the system, so that the output signal of the switch matrix is ​​directly connected to the navigation signal receiving unit, and the time delay measurement value of the current state is measured and used as the time delay control target.

[0085] Step 4: In the payload management unit, set the currently measured delay value as the satellite navigation signal delay control target, so that the delay measurement value of the measurement point under the current switch matrix setting conditions is controlled within the target range;

[0086] Step 5: The navigation signal receiving unit performs real-time signal reception and time delay measurement, and simultaneously measures the temperature of the navigation signal receiving unit. The navigation signal receiving unit then compensates for the systematic deviation between the measured temperature and the time delay measurement. Typically, the results of both the time delay and temperature measurements are smoothed through multi-point processing. Due to the slow temperature change, it is usually sufficient to output the time delay-compensated measurement value at 1 time / second.

[0087] In this embodiment, the navigation signal receiving unit typically generates a delay measurement value every 100ms and 10 delay measurement values ​​within 1s. The 10 measurement values ​​within 1s are averaged and smoothed to obtain the delay measurement value at the current 1s moment.

[0088] Step Six: The navigation signal receiving unit sends the real-time delay measurement results to the load management unit;

[0089] Step 7: The load management unit performs a cross-difference between the received delay measurement value and the set target delay value, and then performs smoothing filtering on the result.

[0090] For example, the load management unit can use the delay adjustment amount of the current time and the previous 3-5 seconds to perform windowing smoothing, and obtain the delay adjustment amount used for the current adjustment;

[0091] Step 8: Compare with the set target error control range. Details are as follows:

[0092]

[0093] in, The actual results of the current measurement, For the set target delay value, The error range of the control target delay is set.

[0094] If the difference between the two results is less than or equal to the target control error, no adjustment is needed, and the adjustment amount remains unchanged from the previous state.

[0095] If the difference between the two results is greater than or equal to the target control error, then an effective time delay adjustment is required.

[0096] Step 9: If the cross-difference result is greater than or equal to the target control error, calculate the effective time delay adjustment amount, as follows:

[0097]

[0098] This is the total adjustment delay amount. The actual results of the current measurement, For the set target delay value, The error range of the set control target delay;

[0099] Step 10: The load management unit generates a delay adjustment precision based on the navigation signal, decomposing the effective delay adjustment amount into integer and fractional delay adjustment amounts. For example, the delay to be adjusted is... , is the total delay adjustment, n is the integer delay adjustment, and m is the fractional delay adjustment.

[0100] Step 11: The load management unit sends integer and fractional delay adjustment values ​​to the navigation signal generation unit.

[0101] For example: Integer time delay adjustment is usually achieved by designing a register variable that allows n to be directly written as a parameter; m is the fractional adjustment amount, which is actually a set of filter parameters corresponding to the delay filter. After writing the corresponding filter parameters, the signal can achieve fractional-level time delay adjustment.

[0102] Step 12: The navigation signal generation unit updates the relevant time delay parameters according to the time delay adjustment amount.

[0103] Step Thirteen: When the delay of the measured signal changes, repeat steps three through thirteen above to maintain the stability of the navigation signal's delay. This process also applies to the requirements of navigation signal delay uncertainty caused by multiple power-on / off and reset cycles.

[0104] In this embodiment, as Figure 3As shown, a stability control system for navigation signals is established according to the method of this invention. The integer time delay adjustment of the navigation signal generation unit is T = 1 / 1718.64MHz. A delay filter is used to achieve a decimal adjustment accuracy of 14ps. The average time delay measurement at the current moment is set as the target time delay value, and the target error control range is 35ps. Experimental results using the method of this invention, measured under varying temperature conditions of 22.64℃, show that the change in the time delay measurement value can be controlled to 33.911ps.

[0105] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

[0106] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for controlling the time delay stability of satellite navigation signals, characterized in that, include: S1. Based on the preset temperature control range, calibrate the relationship between temperature and time delay to obtain the correspondence between temperature and time delay; S2. Select the monitoring point for the time delay to be measured in the satellite navigation system; S3. Measure the time delay of the monitoring point and determine the time delay measurement value of the current state; S4. Set the current delay measurement value as the target for satellite navigation signal delay control; S5. Based on the satellite navigation signal delay control target, set the target delay value and target error control range for the satellite navigation signal; S6. Perform real-time signal reception, time delay measurement, and temperature measurement. Based on the temperature-time delay correspondence, compensate for the time delay measurement results to obtain the time delay value. S7. The difference between the delay value and the target delay value is calculated to obtain the difference result; S8. Based on the cross-difference results and the target error control range, obtain the effective time delay adjustment amount; S9. Decompose the effective delay adjustment amount to obtain integer delay adjustment precision and fractional delay adjustment precision; S10. Adjust the delay of the navigation signal according to the integer delay adjustment precision and the fractional delay adjustment precision; S11. When the time delay of the measured signal changes, repeat the above steps S3~S10 to always keep the time delay of the navigation signal within the set control target range and maintain the stability of the navigation signal's time delay. Based on the preset temperature control range, the temperature-time delay relationship is calibrated to obtain the corresponding relationship between temperature and time delay, specifically as follows: Within the temperature control range, the navigation signal receiving unit measures and statistically analyzes the time delay measurement error and the time delay average value for each X degrees Celsius segment. Less than the error precision The time delay measurement error is averaged to obtain the mean time delay; Based on the average time delay, establish the correspondence between temperature and time delay; The effective time delay adjustment amount is obtained based on the cross-difference result and the target error control range. The specific method is as follows: judge If the condition is not met, calculate the valid delay adjustment amount; if it is met, retain the previous delay adjustment amount as the valid delay adjustment amount. The actual results of the current measurement, For the set target delay value, The error range of the set control target delay; The calculation of the effective delay adjustment amount is specifically as follows: in, This is the total adjustment delay amount. The actual results of the current measurement, For the set target delay value, The error range of the set control target delay; The step of decomposing the effective delay adjustment amount to obtain the required delay parameters is specifically as follows: in, is the total adjusted delay amount, n is the integer delay adjustment parameter, m is the fractional delay adjustment parameter, and T is the integer delay adjustment precision. Adjust the precision for decimal delay.

2. The satellite navigation signal delay stability control method according to claim 1, characterized in that: The error precision is specifically as follows: in, To ensure measurement error accuracy, For RF front-end bandwidth, For pseudocode symbol width, For loop noise bandwidth, For the relevant spacing, For the relevant integration time, This represents the signal-to-noise ratio.

3. A satellite navigation signal time delay stability control system, characterized in that, The satellite navigation signal delay stability control method as described in claim 1 includes a reference time-frequency unit, a navigation signal generation unit, a navigation signal broadcasting system, a payload management unit, a switching matrix, a navigation signal receiving unit, and a constant temperature control unit; wherein, The reference time-frequency unit generates the system synchronization time-frequency signal, which is used as a phase reference for time delay measurement and as a clock signal of the same frequency required for navigation signal generation; The navigation signal generation unit adjusts the time delay of the navigation signal based on the time difference result of the load management unit, generates a medium frequency or radio frequency low power navigation signal, and sends it to the navigation signal broadcasting system and the switching matrix. The navigation signal broadcasting system filters, converts, amplifies, and splits the intermediate frequency or radio frequency low-power navigation signal sent by the navigation signal generation unit to generate a transmitted navigation signal, which is then sent to the antenna. The antenna transmits navigation signals in the airspace; The navigation signal receiving unit captures, tracks, and measures the time delay of intermediate frequency or radio frequency navigation signals generated by different monitoring points forwarded by the switch matrix, and sends the time delay measurement results to the load management unit. The switching matrix, based on the channel switching command sent by the load management unit, selects the intermediate frequency or radio frequency low-power navigation signal generated by the corresponding navigation signal generation unit as the output signal and forwards it to the navigation signal receiving unit. The load management unit statistically analyzes the time delay measurement results sent by the navigation signal receiving unit, compares them with the predetermined time delay parameters, generates a time difference result, and sends it to the navigation signal generation unit. The temperature control unit controls the ambient temperature of the navigation signal receiving unit, ensuring that the navigation signal receiving unit operates in an environment with constant or minimal temperature variation.

4. A satellite navigation signal time delay stability control system according to claim 3, characterized in that: The navigation signal generation unit includes an integer delay module, a fractional delay module, and a register. The integer delay module reads integer delay parameters from the register and applies a digital domain navigation signal delay method to apply an integer delay to the navigation information to generate integer delay information. The fractional delay module reads fractional delay parameters from the register and applies a digital filter delay method to apply a fractional delay to the integer delay information to generate delay-adjusted navigation information.

5. A satellite navigation signal time delay stability control system according to claim 4, characterized in that: The digital domain navigation signal delay method specifically involves delaying the signal by controlling the delay number of clock cycles generated by the navigation signal, with the delay adjustment accuracy being the clock period T generated by the navigation signal.

6. A satellite navigation signal time delay stability control system according to claim 4, characterized in that: The digital filter delay method specifically involves adjusting the delay filter parameters. The fractional delay is adjusted; the impulse response of the delay filter is: in, For frequency, This is the decimal time delay adjustment parameter, where n is the time.

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