A radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver

Abstract

The present invention discloses a radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver, which specifically relates to the field of electromagnetic frequency measurement of radio frequency signals, including an identification and extraction module, a trajectory reconstruction module, a path switching module, and a prediction and compensation module; the identification and extraction module is used to divide the original radio frequency data stream into equal time segments, and extract the frequency response sequence in each time segment, and mark the time segment that meets the conditions as a frequency masking response segment based on the threshold judgment results of the frequency change speed and the amplitude change slope. By constructing a joint judgment mechanism of the frequency change speed and the amplitude change slope, combined with the frequency jump trend fitting and trajectory connection point reconstruction method, the frequency masking response segment is dynamically identified and its internal frequency evolution path is restored to solve the problem that the frequency blind area caused by geomagnetic disturbance cannot be demodulated.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic frequency measurement of radio frequency signals, and more particularly to a radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver. Background Art

[0002] In space electromagnetic tomography and geomagnetic anomaly monitoring missions, orbiting satellites are often required to perform high-sensitivity radio frequency measurement and spectrum evolution analysis of electromagnetic disturbances caused by solar activity, plasma fluctuations, and coronal ejections. These capabilities rely particularly on capturing the instantaneous frequency response of weak continuous wave signals in specific frequency bands.

[0003] However, in actual observations, we are often affected by low-frequency, large-amplitude electromagnetic disturbances originating from the geomagnetic ring. These disturbances have strong periodicity and long-wave characteristics. Not only do they continuously superimpose in the spatial electromagnetic environment to form a wide-area interference noise floor, but they also cause low-frequency tailing and frequency baseline offset in the frequency measurement system. This causes the target frequency that should have been demodulated to passively "sink" or merge with the background, and is completely submerged from the perspective of frequency measurement judgment.

[0004] Because existing broadband instantaneous frequency measurement reception mechanisms generally rely on bandpass window functions and linear frequency response models, they are unable to recover the hidden frequency structure from such large-scale disturbances. This ultimately results in a stable "blind spot" in the frequency measurement channel within the critical detection frequency band, causing important weak signals to be unrecognizable or incorrectly zeroed.

[0005] Therefore, under the complex geomagnetic background, how to recover the swallowed target frequency trajectory from the frequency masking phenomenon caused by continuous disturbance has become the core issue restricting the performance of space electromagnetic frequency measurement system. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver. By constructing a joint judgment mechanism of frequency change speed and amplitude change slope, combined with frequency jump trend fitting and trajectory connection point reconstruction methods, the system dynamically identifies the frequency masking response segment and restores its internal frequency evolution path, so as to solve the problem that the frequency blind spot caused by geomagnetic disturbance cannot be demodulated.

[0007] To achieve the above-mentioned object, the present invention provides the following technical solutions: a radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver, comprising an identification and extraction module, a trajectory reconstruction module, a path switching module, and a prediction and compensation module;

[0008] The identification and extraction module is used to divide the original RF data stream into equal time segments and extract the frequency response sequence in each time segment. Based on the threshold judgment results of the frequency change speed and amplitude change slope, the time segment that meets the conditions is marked as a frequency masking response segment;

[0009] The trajectory reconstruction module is used to extract and judge the frequency direction jump trend of the frequency masking response segment in the disturbance response description data, and construct the frequency trajectory connection points by fitting the frequency direction trend line. The frequency trajectory connection points are interpolated to form a continuous frequency evolution trajectory to form the target frequency recovery result;

[0010] The path switching module is used to compare the target frequency recovery result with the original frequency response sequence, replace the original frequency response sequence in the time segment that meets the conditions based on the judgment result of the frequency difference sequence, and determine whether to execute the frequency measurement path switching through the masking compensation mark to generate the alternative frequency measurement result under the geomagnetic disturbance environment;

[0011] The prediction compensation module is used to extract the frequency jump error in the alternative frequency measurement result, construct a frequency disturbance prediction template and generate a frequency masking prediction window, construct a predicted frequency trajectory according to the frequency direction change trend, and generate an early frequency recovery result.

[0012] In a preferred embodiment, the identification and extraction module is used to divide the original radio frequency data stream obtained by the microwave broadband instantaneous frequency measurement receiver into equal time segments, and discretely extract the frequency response in each time segment;

[0013] The frequency response sequence extracted from each time segment is used to calculate the frequency change rate and amplitude change slope as a quantitative expression of the frequency behavior in the time segment.

[0014] Determine whether the frequency change rate is within a preset frequency change rate threshold range in at least three consecutive time points, and whether the amplitude change slope is within a preset amplitude change slope threshold range in at least three corresponding consecutive time points. If so, mark the time segment as a frequency slow change response segment; otherwise, skip the current time segment and continue processing the next time segment;

[0015] Determine whether the center frequency of the frequency slow variation response segment is less than a preset center frequency threshold, and whether the duration of the frequency slow variation response segment is greater than a preset duration threshold. If both conditions are met, mark it as a frequency mask response segment. Otherwise, skip the current frequency slow variation response segment, do not mark it as a frequency mask response segment, and continue processing the next time segment.

[0016] After the marking is completed, the time index, center frequency, frequency change speed and amplitude change slope of the frequency masking response segment are output and used as disturbance response description data.

[0017] In a preferred embodiment, the trajectory reconstruction module is used to extract the frequency direction jump trend of each frequency masking response segment in the disturbance response description data and calculate the incremental change curve between adjacent frequency values;

[0018] Determine whether there is a change segment in the incremental change curve where the number of reversals in the frequency increment direction within a continuous time interval is greater than a preset reversal number threshold. If the condition is met, mark the change segment as a suspected frequency evolution inflection point area; otherwise, mark the frequency masking response segment as having no trajectory jump characteristics and terminate the process.

[0019] Perform forward and backward frequency trend line fitting on the suspected frequency evolution inflection point area to obtain the frequency direction trend line before the masking segment and the frequency direction trend line after the masking segment, respectively; extend the frequency direction trend line before the masking segment backward according to its end time to a preset specified fitting time interval, and extend the frequency direction trend line after the masking segment forward according to its start time to a preset specified fitting time interval, and search for the intersection point of the lower limit of the frequency difference in the extended overlapping interval of the two frequency direction trend lines as the frequency trajectory connection point of the frequency masking response segment;

[0020] Through the fitting function of the frequency trajectory connection points and the frequency direction trend lines on both sides of the frequency masking response segment, the frequency trajectory connection points are interpolated to form a continuous frequency evolution trajectory as the target frequency recovery result.

[0021] In a preferred embodiment, the path switching module is used to perform a one-to-one comparison between the target frequency recovery result and the original frequency response sequence output by the microwave broadband instantaneous frequency measurement receiver, and extract a frequency difference sequence between the target frequency recovery result and the original frequency response sequence within the frequency masking response section;

[0022] Determine whether there are frequency differences in consecutive time segments in the frequency difference sequence that are greater than a preset tolerance threshold. If so, replace the original frequency response sequence with the target frequency recovery result in the time segment to form an updated frequency output sequence.

[0023] Matching the updated frequency output sequence with the time index of the frequency masking response segment to generate a frequency correction output segment with a masking compensation mark;

[0024] Determine whether there are three or more frequency correction output segments with masking compensation marks in succession in the updated frequency output sequence. If the condition is met, execute the frequency masking adaptive switching process and switch the frequency measurement path from the original frequency response sequence to the target frequency recovery result; otherwise, keep the frequency measurement path as the original frequency response sequence and terminate the adaptive switching process;

[0025] The frequency measurement path output result after the frequency mask adaptation switching process is marked as an alternative frequency measurement result under the geomagnetic disturbance environment and stored in the interference environment frequency response record sequence.

[0026] In a preferred embodiment, the prediction compensation module is used to extract all frequency hopping position points from the alternative frequency measurement results, and calculate the frequency hopping error corresponding to each frequency hopping position point to form a frequency hopping error sequence;

[0027] Determine whether there are error segments in the frequency hopping error sequence with consistent error directions and a time interval less than a preset interval threshold. If the conditions are met, mark the error segment as a frequency disturbance prediction template. Otherwise, store the frequency hopping error sequence as a frequency measurement error record in the error buffer;

[0028] The time interval in the frequency disturbance prediction template is used as the prediction window period parameter, and the end time index of the frequency disturbance prediction template is used as the prediction window starting point to generate a frequency masking prediction window;

[0029] The time index covered by the frequency masking prediction window is used to extract the corresponding time period in the original frequency response sequence. A predicted frequency trajectory is constructed based on the frequency direction change trend extracted from the frequency disturbance prediction template. The predicted frequency trajectory is stored in the frequency trajectory cache and marked as the early frequency recovery result generated based on disturbance prediction.

[0030] In a preferred embodiment, the identification and extraction module defines For time segments Whether to mark as frequency masking response section;

[0031] ;

[0032] in For time segments Internal time point Corresponding frequency response value; For time segments Internal time point The corresponding amplitude response value; Indicates the frequency change speed; Indicates the slope of amplitude change; For time segments The set of sampling time points; is the lower threshold of the frequency change speed; is the upper threshold of the frequency change speed; is the lower threshold of the amplitude change slope; is the upper threshold of the amplitude change slope; For time segments The center frequency of is the upper limit threshold of the center frequency; Represents a time segment duration; is the duration threshold; is a logic decision function, which is 1 if it is established, otherwise it is 0; Indicates logical relationship and; Indicates all.

[0033] In a preferred embodiment, in the trajectory reconstruction module, define is the reconstructed frequency evolution trajectory in time The value on

[0034] ;

[0035] ;

[0036] in is an interpolation function, which is used to connect the frequency direction trend line and the frequency trajectory connection point to form a continuous trajectory; is the interpolation starting point; It is the frequency direction trend line extension function before the frequency masking response section; It is the frequency direction trend line extension function after the frequency masking response section; A time index set for searching the interpolation starting point; Indicates the absolute value symbol; Indicates the time point corresponding to the lower limit of the difference;

[0037] ;

[0038] in The frequency direction trend line extension function before the frequency masking response segment is at the interpolation starting point Function value on ; The frequency direction trend line extension function after the frequency masking response segment is at the interpolation starting point The function value on Indicates the multiplication symbol; the linear weight function of the interpolation segment Defined as:

[0039] ;

[0040] in is the duration of the interpolation transition interval; Indicates the range of conditions under which the formula is valid.

[0041] In a preferred embodiment, the frequency direction trend line extension function before the frequency masking response section Expressed as:

[0042] ;

[0043] Frequency-direction trendline extension function after the frequency masking response segment Expressed as:

[0044] ;

[0045] in time The original frequency response value on ; is the width of the sliding time window; Indicates the symbol for continuous multiplication; is the second-order derivative of the frequency response in time; represents the coefficient of the second derivative of the frequency response in the trend line before the masking segment; It represents the suppression coefficient of the second-order derivative of the frequency response in the trend line after the masking segment; is the exponential decay factor in the time direction before the masking segment; is the exponential weighting factor in the time direction after the masking period; Exponential decay function.

[0046] In a preferred embodiment, in the path switching module, define Indicates time Determine whether to use the restored result instead of the original result;

[0047] ;

[0048] ;

[0049] ;

[0050] in is the original frequency response sequence in time The value on The target frequency is recovered in time The value on Replace the threshold with the frequency difference; is the updated frequency output value; For the Frequency correction output section with masking compensation mark; Indicates the total number of correction segments in the current judgment cycle; Indicates whether to trigger path switching, where 1 means switching and 0 means keeping; is a logic decision function, which is 1 if it is established, otherwise it is 0; Indicates the symbol for continuous multiplication; Indicates the absolute value symbol.

[0051] In a preferred embodiment, the prediction compensation module defines is the set of time points in the prediction template;

[0052] ;

[0053] ;

[0054] in For the The time index of the jump error; is the frequency jump error in time The value on ; express The symbol, when When the value is +1, The value is -1 when When the value is 0; is the upper threshold of the time interval; Indicates time The predicted frequency recovery results on represents the frequency prediction trajectory generation function based on the prediction template and the fitting trend function; Represents the frequency direction change function obtained by fitting the historical trend; It is a set symbol, indicating all a collection of components; Indicates the logical relationship and.

[0055] The technical effects and advantages of the present invention are as follows:

[0056] To address the problem that weak continuous wave signals in space electromagnetic tomography tasks are easily masked by the geomagnetic disturbance background and cannot be demodulated using traditional frequency measurement structures, the present invention uses a joint threshold recognition mechanism for frequency change speed and amplitude change slope to construct a low-frequency disturbance response extraction mechanism during electromagnetic frequency measurement. This mechanism can determine the masked section without relying solely on the center frequency, thereby effectively recovering the blind area signal in the frequency measurement channel.

[0057] By analyzing the frequency increment reversal behavior in the identified frequency masking response segment, fitting the previous and next trend lines and performing interpolation calculations at the connection points, a complete frequency evolution trajectory is constructed. This can restore the truncated frequency measurement path in the case of nonlinear jumps, improving the trajectory integrity and time consistency in continuous frequency measurement.

[0058] By comparing the difference between the target frequency recovery result and the original frequency measurement result and accumulating the frequency correction output segment, we designed the trigger conditions for multiple segments of shielding compensation marks. This allows for dynamic frequency measurement path replacement while avoiding path oscillation, effectively enhancing the adaptive robustness of the frequency measurement output in electromagnetic disturbance environments.

[0059] By analyzing the time distribution and directional trend of frequency hopping errors, a disturbance prediction template and frequency masking prediction window are constructed. The predicted frequency trajectory is generated before entering the masking state, forming a prediction compensation path based on the disturbance behavior pattern, thereby improving the frequency measurement and processing system's frequency measurement warning and early modeling capabilities in periodic interference scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 Schematic diagram of the system module of the present invention. DETAILED DESCRIPTION

[0061] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0062] Refer to the instruction manual Figure 1 , a radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to an embodiment of the present invention includes an identification and extraction module, a trajectory reconstruction module, a path switching module, and a prediction and compensation module;

[0063] The identification and extraction module is used to divide the original RF data stream into equal time segments and extract the frequency response sequence in each time segment. Based on the threshold judgment results of the frequency change speed and amplitude change slope, the time segment that meets the conditions is marked as a frequency masking response segment;

[0064] The trajectory reconstruction module is used to extract and judge the frequency direction jump trend of the frequency masking response segment in the disturbance response description data, and construct the frequency trajectory connection points by fitting the frequency direction trend line. The frequency trajectory connection points are interpolated to form a continuous frequency evolution trajectory to form the target frequency recovery result;

[0065] The path switching module is used to compare the target frequency recovery result with the original frequency response sequence, replace the original frequency response sequence in the time segment that meets the conditions based on the judgment result of the frequency difference sequence, and determine whether to execute the frequency measurement path switching through the masking compensation mark to generate the alternative frequency measurement result under the geomagnetic disturbance environment;

[0066] The prediction compensation module is used to extract the frequency jump error in the alternative frequency measurement result, construct a frequency disturbance prediction template and generate a frequency masking prediction window, construct a predicted frequency trajectory according to the frequency direction change trend, and generate an early frequency recovery result.

[0067] The identification and extraction module is used to divide the original radio frequency data stream obtained by the microwave broadband instantaneous frequency measurement receiver into equal time segments and discretely extract the frequency response in each time segment;

[0068] The frequency response sequence extracted from each time segment is used to calculate the frequency change rate and amplitude change slope as a quantitative expression of the frequency behavior in the time segment.

[0069] Determine whether the frequency change rate is within a preset frequency change rate threshold range in at least three consecutive time points, and whether the amplitude change slope is within a preset amplitude change slope threshold range in at least three corresponding consecutive time points. If so, mark the time segment as a frequency slow change response segment; otherwise, skip the current time segment and continue processing the next time segment;

[0070] Determine whether the center frequency of the frequency slow variation response segment is less than a preset center frequency threshold, and whether the duration of the frequency slow variation response segment is greater than a preset duration threshold. If both conditions are met, mark it as a frequency mask response segment. Otherwise, skip the current frequency slow variation response segment, do not mark it as a frequency mask response segment, and continue processing the next time segment.

[0071] After the marking is completed, the time index, center frequency, frequency change speed and amplitude change slope of the frequency masking response segment are output and used as disturbance response description data.

[0072] The trajectory reconstruction module is used to extract the frequency direction jump trend of each frequency masking response segment in the disturbance response description data and calculate the incremental change curve between adjacent frequency values;

[0073] Determine whether there is a change segment in the incremental change curve where the number of reversals in the frequency increment direction within a continuous time interval is greater than a preset reversal number threshold. If the condition is met, mark the change segment as a suspected frequency evolution inflection point area; otherwise, mark the frequency masking response segment as having no trajectory jump characteristics and terminate the subsequent process;

[0074] Perform forward and backward frequency trend line fitting on the suspected frequency evolution inflection point area to obtain the frequency direction trend line before the masking segment and the frequency direction trend line after the masking segment, respectively; extend the frequency direction trend line before the masking segment backward according to its end time to a preset specified fitting time interval, and extend the frequency direction trend line after the masking segment forward according to its start time to a preset specified fitting time interval, and search for the intersection point of the lower limit of the frequency difference in the extended overlapping interval of the two frequency direction trend lines as the frequency trajectory connection point of the frequency masking response segment;

[0075] Through the fitting function of the frequency trajectory connection points and the frequency direction trend lines on both sides of the frequency masking response segment, the frequency trajectory connection points are interpolated to form a continuous frequency evolution trajectory as the target frequency recovery result.

[0076] The path switching module is used to perform a one-to-one comparison between the target frequency recovery result and the original frequency response sequence output by the microwave broadband instantaneous frequency measurement receiver, and extract the frequency difference sequence between the target frequency recovery result and the original frequency response sequence within the frequency masking response section;

[0077] Determine whether there are frequency differences in consecutive time segments in the frequency difference sequence that are greater than a preset tolerance threshold. If so, replace the original frequency response sequence with the target frequency recovery result in the time segment to form an updated frequency output sequence.

[0078] Matching the updated frequency output sequence with the time index of the frequency masking response segment to generate a frequency correction output segment with a masking compensation mark;

[0079] Determine whether there are three or more frequency correction output segments with masking compensation marks in succession in the updated frequency output sequence. If the condition is met, execute the frequency masking adaptive switching process and switch the frequency measurement path from the original frequency response sequence to the target frequency recovery result; otherwise, keep the frequency measurement path as the original frequency response sequence and terminate the adaptive switching process;

[0080] The frequency measurement path output result after the frequency mask adaptation switching process is marked as an alternative frequency measurement result under the geomagnetic disturbance environment and stored in the interference environment frequency response record sequence.

[0081] The prediction compensation module is used to extract all frequency hopping position points from the alternative frequency measurement results, and calculate the frequency hopping error corresponding to each frequency hopping position point to form a frequency hopping error sequence;

[0082] Determine whether there are error segments in the frequency hopping error sequence with consistent error directions and a time interval less than a preset interval threshold. If the conditions are met, mark the error segment as a frequency disturbance prediction template. Otherwise, store the frequency hopping error sequence as a frequency measurement error record in the error buffer;

[0083] The time interval in the frequency disturbance prediction template is used as the prediction window period parameter, and the end time index of the frequency disturbance prediction template is used as the prediction window starting point to generate a frequency masking prediction window;

[0084] The time index covered by the frequency masking prediction window is used to extract the corresponding time period in the original frequency response sequence. A predicted frequency trajectory is constructed based on the frequency direction change trend extracted from the frequency disturbance prediction template. The predicted frequency trajectory is stored in the frequency trajectory cache and marked as the early frequency recovery result generated based on disturbance prediction.

[0085] It should be noted that in the formula structure involved in this solution, dimensionless terms can serve as proportionality or structural adjustment factors. When combined with quantities with units, they only play a numerical scaling role and do not introduce new physical dimensions. Therefore, they will not change or confuse the overall unit system of expression. This combination of "dimensionless terms and units" can be understood as a composite structural expression commonly used in mathematical and physical modeling, conforming to the principle of dimensional consistency and having a clear physical interpretation basis.

[0086] Secondly, in the formula structure of this scheme, if multiple variables with different physical units are involved, including but not limited to time, mass or energy variables, their joint appearance is to express the collaborative modeling relationship of multiple physical mechanisms. Each variable can be formed into a unified structure through function mapping, ratio combination or normalization adjustment. The units and meanings are clear, and the overall expression conforms to the principle of dimensional consistency and the common formula of engineering modeling.

[0087] In this solution, any design constants, weights, adjustment factors, threshold parameters, and proportional coefficients are adjustable control parameters for different application environments. Their values depend on the target device configuration, data input characteristics, and performance optimization goals. During the implementation phase, they are set within a reasonable range through model verification, performance constraints, or engineering calibration. Although these parameters do not have unique preset values, they have clear adjustment logic and calculation paths, and are part of the deterministic setting process in engineering implementation. The purpose of such setting is to ensure that the solution is both universally adaptable, reproducible, and operable, without affecting its technical clarity and feasibility.

[0088] Defined in the recognition extraction module For time segments Whether to mark it as a frequency masking response segment (1 for yes, 0 for no);

[0089] ;

[0090] in For time segments Internal time point Corresponding frequency response value; For time segments Internal time point The corresponding amplitude response value; Indicates the frequency change rate (time derivative); Represents the slope of amplitude change (derivative with respect to time); For time segments The set of sampling time points; is the lower threshold of the frequency change speed; is the upper threshold of the frequency change speed; is the lower threshold of the amplitude change slope; is the upper threshold of the amplitude change slope; in this time segment Under the premise of being identified as a frequency slow-changing response section, For time segments The center frequency of is the upper limit threshold of the center frequency; in this time segment Under the premise of being identified as a frequency slow-changing response section, Represents a time segment duration; is the duration threshold; is a logic decision function, which is 1 if it is established, otherwise it is 0; Indicates the logical relationship and (AND); Indicates all, used to express that every element in the set satisfies a certain condition.

[0091] In the trajectory reconstruction module, define is the reconstructed frequency evolution trajectory in time The value on

[0092] ;

[0093] ;

[0094] in is an interpolation function, which is used to connect the frequency direction trend line and the frequency trajectory connection point to form a continuous trajectory; The interpolation starting point is the time point where the difference between the two frequency-direction trend line functions is the smallest within the search interval. It is the frequency direction trend line extension function before the frequency masking response section; It is the frequency direction trend line extension function after the frequency masking response section; A time index set for searching the interpolation starting point; Indicates the absolute value symbol; Indicates the time point corresponding to the lower limit of the difference;

[0095] ;

[0096] in The frequency direction trend line extension function before the frequency masking response segment is at the interpolation starting point Function value on ; The frequency direction trend line extension function after the frequency masking response segment is at the interpolation starting point The function value on Indicates the multiplication symbol; the linear weight function of the interpolation segment Defined as:

[0097] ;

[0098] in is the duration of the interpolation transition interval; Indicates the conditional range for the formula to be valid, which is used to limit the formula to be valid within a specific interval.

[0099] Frequency direction trend line extension function before the frequency masking response segment Expressed as:

[0100] ;

[0101] Frequency-direction trendline extension function after the frequency masking response segment Expressed as:

[0102] ;

[0103] in time The original frequency response value on; In addition, in the above formula, time Indicates the time point of the current trend calculation, time Represents the time points used to traverse the integration window; is the width of the sliding time window, which is used to construct the trend interval; Indicates the symbol for continuous multiplication; The second-order derivative of the frequency response in time represents the acceleration of change and is used to determine the smoothness or sharpness of the trend. Represents the enhancement coefficient of the second-order derivative of the frequency response in the trend line before the masking segment. The enhancement coefficient of the second-order derivative of the frequency response in the trend line before the masking segment is used to highlight the rapid inflection point changes in the trajectory before the masking segment. In practical applications, its value can be combined with the steepness of the change in the frequency response in the historical interval. It should be larger when the response curvature fluctuates significantly, and should be appropriately reduced when the response is relatively flat to avoid overfitting. Indicates the suppression coefficient of the second-order derivative of the frequency response in the trend line after the masking section. The suppression coefficient of the second-order derivative of the frequency response in the trend line after the masking section is used to smooth the trend change after the transition section to prevent local severe disturbances from misleading the fitting results. In practical applications, its value is based on the fluctuation stability of the frequency response data after the masking section. When the fluctuation is severe, the suppression ability is appropriately enhanced, and the restriction can be relaxed when the fluctuation pattern is clear. The exponential decay factor in the time direction before the masking segment is used to determine the degree of retention of the historical frequency response value in the trend calculation. Its value can be adjusted according to the historical time window covered by the trend analysis. If the historical trajectory information is critical, the decay rate should be slowed down. If only the short-term direction needs to be captured, the decay rate can be increased to increase responsiveness. The exponential weighting factor in the time direction after the masking period is used to control the degree of attention paid to recent response points in frequency trend modeling. Its value can be determined based on the predictability of the frequency trend after the masking period. When the trend continuity is strong, the weighting factor should be appropriately increased. When the trend is uncertain or the fluctuation is strong, the weighting factor should be kept gentle to prevent the introduction of errors. Exponential decay function, in the above formula, the exponential decay function is used to simulate the decrease in sensitivity to the distance of time; in addition, the formula structure in the above formula is as follows: Indicates that in the interval Internal variables The continuous integral of is used to reflect the trend accumulation.

[0104] In the path switching module, define Indicates time Determine whether to use the restored result to replace the original result (1 for replacement, 0 for retention);

[0105] ;

[0106] ;

[0107] ;

[0108] in is the original frequency response sequence in time The value on The target frequency is recovered in time The value on Replace the threshold with the frequency difference; is the updated frequency output value; For the Frequency correction output section with masking compensation mark; Indicates the total number of correction segments in the current judgment cycle; Indicates whether to trigger path switching, where 1 means switching and 0 means keeping; is a logic decision function, which is 1 if it is established, otherwise it is 0; Indicates the symbol for continuous multiplication; Indicates the absolute value symbol.

[0109] Defined in the prediction compensation module is the set of time points in the prediction template;

[0110] ;

[0111] ;

[0112] in For the The time index of the jump error; is the frequency jump error in time The value on ; express The symbol, when When the value is +1, The value is -1 when When the value is 0; is the upper threshold of the time interval; Indicates time The predicted frequency recovery results on represents the frequency prediction trajectory generation function constructed based on the prediction template and the fitting trend function; Represents the frequency direction change function obtained by fitting the historical trend; It is a set symbol, indicating all a collection of components; Indicates the logical relationship AND.

[0113] It should be generally explained that the technical solution of the present invention is aimed at the frequency measurement blind spot problem caused by frequency masking of weak radio frequency signals due to geomagnetic disturbances in orbital observation missions. In the prior art, the commonly used frequency measurement models use fixed frequency windows or linear filter structures, which cannot accurately recover the signal trajectory under strong background interference. In particular, when nonlinear jump behaviors such as interruption, drift or fallback occur in the frequency evolution process, conventional means cannot determine whether the frequency continuity is truly interrupted or simply masked by the background signal. The present invention is centered around the core goal of "how to reconstruct the masked frequency trajectory" and proposes an application system architecture.

[0114] First, the identification and extraction module is used to undertake the entry task of the solution, namely, to identify time segments with frequency masking characteristics from the raw RF data stream obtained by the microwave broadband instantaneous frequency measurement receiver. The execution logic uses a combined threshold judgment of "frequency change speed" and "amplitude change slope" because during the frequency masking stage, the signal generally exhibits two characteristics: a narrowing frequency fluctuation range and a smooth amplitude change. Even if a weak signal has been "suppressed" to near the frequency response baseline by background disturbances, the coherence of its local slope in the time dimension may still be preserved. Therefore, the design does not use the frequency value itself as the judgment basis, but instead establishes a composite threshold based on the speed and direction of the change trend, thereby reducing sensitivity to amplitude and center value offsets. In addition, by further introducing the conditions of center frequency and duration, it ensures that only those segments that maintain the masking characteristics for a sufficient period of time are selected, eliminating transient anomalies caused by occasional interference.

[0115] After completing the initial identification of the masking response segment, the core task of the trajectory reconstruction module is to determine whether there is a broken evolution trend in the frequency trajectory and to construct a continuous trajectory at the break point. The key point of the trajectory reconstruction module is not a simple curve fitting, but to determine whether there is a trend break from rising to falling or from falling to rising by analyzing the number of reversals in the frequency increment direction. In real scenarios, the frequency direction changes of weak signals before and after being masked are usually inconsistent. For example, a slowly rising target signal may quickly decline or stagnate after being "suppressed" by interference. Therefore, relying solely on trend line extension is prone to overfitting or misjudgment. Therefore, this module designs a bidirectional fitting structure for forward and backward trend lines, and sets a controllable fitting extension time range. The minimum frequency difference point is found in the overlapping area of the trend lines on both sides as the trajectory connection point. In essence, the masked segment is surrounded by a known trend and the frequency change logic is inferred in the frequency region that is not directly observed. Finally, the masked segment is reconstructed into a continuous trajectory using a fitting function, thereby recovering the target frequency evolution path.

[0116] The task of the path switching module is not simply to output the recovery result, but to determine whether to incorporate the recovery result into the frequency measurement path to replace the original frequency response sequence. The reason for not directly using the recovered trajectory is that some frequency-masked response segments may have trajectory inference errors, especially when the interference is extremely complex or the confidence level of the predicted connection point is insufficient. For this reason, this module introduces the concept of "frequency difference sequence" to compare the difference between the recovered trajectory and the original frequency measurement value. The replacement operation is only performed when the difference exceeds the preset tolerance threshold. Furthermore, to prevent path oscillation caused by isolated error segments, the path switching module constructs a "compensation mark accumulation judgment mechanism". Path switching is triggered only when three or more frequency correction output segments appear continuously. Based on the principle of "stability first", it avoids destroying the original continuity and stability of the frequency measurement system due to excessive response.

[0117] Finally, the prediction and compensation module introduces a "frequency disturbance prediction template" structure, which is proposed to address the problem of periodic or predictable frequency shielding in long-term orbital operation missions. Since many geomagnetic disturbances have relatively regular behaviors, such as polar disturbances stimulated by the solar wind, which usually recur at certain orbital altitudes, the frequency jump error direction and time interval are extracted from the historical alternative frequency measurement results, and an "error segment" is constructed to generate a prediction window in advance. Once this prediction window covers the upcoming shielding time period in the original frequency response sequence, there is no need to wait for the shielding segment to be explicitly identified, and the frequency trajectory can be directly constructed for early compensation. This structure upgrades passive compensation to active prediction, which is also a forward-looking part in practical applications and is suitable for frequency measurement guarantee missions in multi-orbit and long-term operations.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver, comprising an identification and extraction module, a trajectory reconstruction module, a path switching module, and a prediction and compensation module, characterized in that: The identification and extraction module is used to divide the original RF data stream into equal time segments and extract the frequency response sequence in each time segment. Based on the threshold judgment results of the frequency change speed and amplitude change slope, the time segment that meets the conditions is marked as a frequency masking response segment; The trajectory reconstruction module is used to extract and judge the frequency direction jump trend of the frequency masking response segment in the disturbance response description data, and construct the frequency trajectory connection points by fitting the frequency direction trend line. The frequency trajectory connection points are interpolated to form a continuous frequency evolution trajectory to form the target frequency recovery result; The path switching module is used to compare the target frequency recovery result with the original frequency response sequence, replace the original frequency response sequence in the time segment that meets the conditions based on the judgment result of the frequency difference sequence, and determine whether to execute the frequency measurement path switching through the masking compensation mark to generate the alternative frequency measurement result under the geomagnetic disturbance environment; The prediction compensation module is used to extract the frequency jump error in the alternative frequency measurement result, construct a frequency disturbance prediction template and generate a frequency masking prediction window, construct a predicted frequency trajectory according to the frequency direction change trend, and generate an early frequency recovery result.

2. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 1, characterized in that: The identification and extraction module is used to divide the original radio frequency data stream obtained by the microwave broadband instantaneous frequency measurement receiver into equal time segments and discretely extract the frequency response in each time segment; The frequency response sequence extracted from each time segment is used to calculate the frequency change rate and amplitude change slope as a quantitative expression of the frequency behavior in the time segment. Determine whether the frequency change rate is within a preset frequency change rate threshold range in at least three consecutive time points, and whether the amplitude change slope is within a preset amplitude change slope threshold range in at least three corresponding consecutive time points. If so, mark the time segment as a frequency slow change response segment; otherwise, skip the current time segment and continue processing the next time segment; Determine whether the center frequency of the frequency slow variation response segment is less than a preset center frequency threshold, and whether the duration of the frequency slow variation response segment is greater than a preset duration threshold. If both conditions are met, mark it as a frequency mask response segment. Otherwise, skip the current frequency slow variation response segment, do not mark it as a frequency mask response segment, and continue processing the next time segment. After the marking is completed, the time index, center frequency, frequency change speed and amplitude change slope of the frequency masking response segment are output and used as disturbance response description data.

3. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 2, characterized in that: The trajectory reconstruction module is used to extract the frequency direction jump trend of each frequency masking response segment in the disturbance response description data and calculate the incremental change curve between adjacent frequency values; Determine whether there is a change segment in the incremental change curve where the number of reversals in the frequency increment direction within a continuous time interval is greater than a preset reversal number threshold. If the condition is met, mark the change segment as a suspected frequency evolution inflection point area; otherwise, mark the frequency masking response segment as having no trajectory jump characteristics and terminate the process. Perform forward and backward frequency trend line fitting on the suspected frequency evolution inflection point area to obtain the frequency direction trend line before the masking segment and the frequency direction trend line after the masking segment, respectively; extend the frequency direction trend line before the masking segment backward according to its end time to a preset specified fitting time interval, and extend the frequency direction trend line after the masking segment forward according to its start time to a preset specified fitting time interval, and search for the intersection point of the lower limit of the frequency difference in the extended overlapping interval of the two frequency direction trend lines as the frequency trajectory connection point of the frequency masking response segment; Through the fitting function of the frequency trajectory connection points and the frequency direction trend lines on both sides of the frequency masking response segment, the frequency trajectory connection points are interpolated to form a continuous frequency evolution trajectory as the target frequency recovery result.

4. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 3, characterized in that: The path switching module is used to perform a one-to-one comparison between the target frequency recovery result and the original frequency response sequence output by the microwave broadband instantaneous frequency measurement receiver, and extract the frequency difference sequence between the target frequency recovery result and the original frequency response sequence within the frequency masking response section; Determine whether there are frequency differences in consecutive time segments in the frequency difference sequence that are greater than a preset tolerance threshold. If so, replace the original frequency response sequence with the target frequency recovery result in the time segment to form an updated frequency output sequence. Matching the updated frequency output sequence with the time index of the frequency masking response segment to generate a frequency correction output segment with a masking compensation mark; Determine whether there are three or more frequency correction output segments with masking compensation marks in succession in the updated frequency output sequence. If the condition is met, execute the frequency masking adaptive switching process and switch the frequency measurement path from the original frequency response sequence to the target frequency recovery result; otherwise, keep the frequency measurement path as the original frequency response sequence and terminate the adaptive switching process; The frequency measurement path output result after the frequency mask adaptation switching process is marked as an alternative frequency measurement result under the geomagnetic disturbance environment and stored in the interference environment frequency response record sequence.

5. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 4, characterized in that: The prediction compensation module is used to extract all frequency hopping position points from the alternative frequency measurement results, and calculate the frequency hopping error corresponding to each frequency hopping position point to form a frequency hopping error sequence; Determine whether there are error segments in the frequency hopping error sequence with consistent error directions and a time interval less than a preset interval threshold. If the conditions are met, mark the error segment as a frequency disturbance prediction template. Otherwise, store the frequency hopping error sequence as a frequency measurement error record in the error buffer; The time interval in the frequency disturbance prediction template is used as the prediction window period parameter, and the end time index of the frequency disturbance prediction template is used as the prediction window starting point to generate a frequency masking prediction window; The time index covered by the frequency masking prediction window is used to extract the corresponding time period in the original frequency response sequence. A predicted frequency trajectory is constructed based on the frequency direction change trend extracted from the frequency disturbance prediction template. The predicted frequency trajectory is stored in the frequency trajectory cache and marked as the early frequency recovery result generated based on disturbance prediction.

6. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 5, characterized in that: Defined in the recognition extraction module For time segments Whether to mark as frequency masking response section; ； in For time segments Internal time point Corresponding frequency response value; For time segments Internal time point The corresponding amplitude response value; Indicates the frequency change speed; Indicates the slope of amplitude change; For time segments The set of sampling time points; is the lower threshold of the frequency change speed; is the upper threshold of the frequency change speed; is the lower threshold of the amplitude change slope; is the upper threshold of the amplitude change slope; For time segments The center frequency of is the upper limit threshold of the center frequency; Represents a time segment duration; is the duration threshold; is a logic decision function, which is 1 if it is established, otherwise it is 0; Indicates logical relationship and; Indicates all.

7. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 6, characterized in that: In the trajectory reconstruction module, define is the reconstructed frequency evolution trajectory in time The value on ； ； in is an interpolation function, which is used to connect the frequency direction trend line and the frequency trajectory connection point to form a continuous trajectory; is the interpolation starting point; It is the frequency direction trend line extension function before the frequency masking response section; It is the frequency direction trend line extension function after the frequency masking response section; A time index set for searching the interpolation starting point; Indicates the absolute value symbol; Indicates the time point corresponding to the lower limit of the difference; ； in The frequency direction trend line extension function before the frequency masking response segment is at the interpolation starting point Function value on ; The frequency direction trend line extension function after the frequency masking response segment is at the interpolation starting point The function value on Indicates the multiplication symbol; the linear weight function of the interpolation segment Defined as: ； in is the duration of the interpolation transition interval; Indicates the range of conditions under which the formula is valid.

8. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 7, characterized in that: Frequency direction trend line extension function before the frequency masking response segment Expressed as: ； Frequency-direction trendline extension function after the frequency masking response segment Expressed as: ； in time The original frequency response value on ; is the width of the sliding time window; Indicates the symbol for continuous multiplication; is the second derivative of the frequency response in time; represents the coefficient of the second derivative of the frequency response in the trend line before the masking segment; It represents the suppression coefficient of the second-order derivative of the frequency response in the trend line after the masking segment; is the exponential decay factor in the time direction before the masking segment; is the exponential weighting factor in the time direction after the masking period; Exponential decay function.

9. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 8, characterized in that: In the path switching module, define Indicates time Determine whether to use the restored result instead of the original result; ； ； ； in is the original frequency response sequence in time The value on The target frequency is recovered in time The value on Replace the threshold with the frequency difference; is the updated frequency output value; For the Frequency correction output section with masking compensation mark; Indicates the total number of correction segments in the current judgment cycle; Indicates whether to trigger path switching, where 1 means switching and 0 means keeping; is a logic decision function, which is 1 if it is established, otherwise it is 0; Indicates the symbol for continuous multiplication; Indicates the absolute value symbol.

10. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 9, characterized in that: Defined in the prediction compensation module is the set of time points in the prediction template; ； ； in For the The time index of the jump error; is the frequency jump error in time The value on ; express The symbol, when When the value is +1, The value is -1 when When the value is 0; is the upper threshold of the time interval; Indicates time The predicted frequency recovery results on represents the frequency prediction trajectory generation function constructed based on the prediction template and the fitting trend function; Represents the frequency direction change function obtained by fitting the historical trend; It is a set symbol, indicating all a collection of components; Indicates the logical relationship and.

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