Radio frequency signal processing system based on microwave broadband instantaneous frequency measurement receiver

Abstract

The invention discloses a radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver, particularly relates to the field of electromagnetic frequency measurement of radio frequency signals, and comprises an identification extraction module, a track reconstruction module, a path switching module and a prediction compensation module. The recognition and extraction module is used for dividing an original radio frequency data stream into equal-length time slices, extracting a frequency response sequence in each time slice, and marking the time slice meeting the condition as a frequency shielding response section according to a threshold judgment result of a frequency change speed and an amplitude change slope. By constructing a combined judgment mechanism of the frequency change speed and the amplitude change slope and combining a frequency hopping trend fitting and track connection point reconstruction method, a frequency shielding response section is dynamically identified, and an internal frequency evolution path is recovered, so that the problem that a frequency blind area caused by geomagnetic disturbance cannot be demodulated is solved.

Description

Technical Field

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

[0002] In the tasks of space electromagnetic tomography and geomagnetic anomaly monitoring, orbital satellites usually need to perform high-sensitivity radio frequency frequency measurement and spectral evolution analysis on electromagnetic disturbances caused by events such as solar activities, plasma fluctuations, and coronal mass ejections. In particular, it depends on capturing the instantaneous frequency response of weak continuous wave signals in specific frequency bands; However, in actual observations, it is often affected by low-frequency macro-amplitude electromagnetic disturbances originating from the geomagnetic belt. This type of disturbance has strong periodicity and long-wave characteristics. It not only continuously superimposes in the space electromagnetic environment to form a wide-area interference background noise, but also causes low-frequency tails and frequency baseline shifts in the frequency measurement system, making the target frequency that should be demodulated passively "sink" or blend with the background and be overall submerged from the perspective of frequency measurement determination; Since existing broadband instantaneous frequency measurement receiving mechanisms generally rely on band-pass window functions and linear frequency response models, they cannot recover the hidden frequency point structure from this type of large-scale disturbance, ultimately resulting in stable "blind zones" in the frequency measurement channels within the key detection frequency bands, causing important weak signals to be unrecognized or wrongly zeroed; Therefore, in a complex geomagnetic background, how to recover the swallowed target frequency trajectory from the frequency masking phenomenon caused by continuous disturbances has become the core problem restricting the performance of space electromagnetic frequency measurement systems. Summary of the Invention

[0003] 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 determination mechanism of the frequency change speed and the amplitude change slope, and combining the frequency jump trend fitting and trajectory connection point reconstruction methods, it dynamically identifies the frequency masking response section and restores the internal frequency evolution path therein to solve the problem that the frequency blind zone caused by geomagnetic disturbances cannot be demodulated.

[0004] To achieve the above object, the present invention provides the following technical solution: A radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver, 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-length time segments, extract the frequency response sequence in each time segment, and mark the time segments that meet the conditions as frequency masking response sections according to the threshold judgment results of the frequency change speed and the amplitude change slope; The trajectory reconstruction module is used to extract and judge the frequency direction jump trend in the frequency masking response section of the perturbation response description data, construct frequency trajectory connection points by fitting the frequency direction trend line, and complement the frequency trajectory connection points into a continuous frequency evolution trajectory through interpolation 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 within the time segment that meets the conditions according to the judgment result of the frequency difference sequence, and determine whether to perform the frequency measurement path switching through the masking compensation flag 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 perturbation prediction template and generate a frequency masking prediction window, and construct a predicted frequency trajectory according to the frequency direction change trend to generate an early frequency recovery result.

[0005] 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-length time segments, and discretely extract the frequency response in each time segment; Calculate the frequency change speed and the amplitude change slope of the frequency response sequence extracted in each time segment as the quantitative expression of the frequency behavior in this time segment; Judge whether the frequency change speed is within the preset frequency change speed threshold range at no less than three consecutive time points, and the amplitude change slope is within the preset amplitude change slope threshold range at the corresponding no less than three consecutive time points. If it is satisfied, mark this time segment as the frequency slow change response section, otherwise skip the current time segment and continue to process the next time segment; Judge whether the center frequency of the frequency slow change response section is less than the preset center frequency threshold, and whether the duration of this frequency slow change response section is greater than the preset duration threshold. If both are satisfied, mark it as the frequency masking response section, otherwise skip the current frequency slow change response section, do not mark it as the frequency masking response section, and continue to process the next time segment; After the marking is completed, output the time index, center frequency, frequency change speed and amplitude change slope of the frequency masking response section as the perturbation response description data.

[0006] In a preferred embodiment, the trajectory reconstruction module is used to extract the frequency direction jump trend in each frequency masking response section of the perturbation 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 of the frequency increment direction within a continuous time interval is greater than the preset reversal number threshold. If the condition is met, mark this change segment as a suspected frequency evolution inflection point area; otherwise, mark this frequency masking response section as having no track jump feature and terminate; 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 section and the frequency direction trend line after the masking section respectively; extend the frequency direction trend line before the masking section backward to the preset specified fitting time interval according to its termination time, and extend the frequency direction trend line after the masking section forward to the preset specified fitting time interval according to its start time. Search for the intersection position point of the lower limit of the frequency difference within the overlapping extended interval of the two frequency direction trend lines as the frequency track connection point of the frequency masking response section; Through the fitting functions of the frequency track connection point and the frequency direction trend lines on both sides of the frequency masking response section, interpolate and complete the frequency track connection point into a continuous frequency evolution track as the target frequency recovery result.

[0007] 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 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 is a frequency difference within a continuous time segment in the frequency difference sequence that is greater than the preset tolerance threshold. If it is satisfied, replace the original frequency response sequence with the target frequency recovery result within this time segment to form an updated frequency output sequence; Match the updated frequency output sequence with the time index of the frequency masking response section to generate a frequency correction output section with a masking compensation mark; Determine whether there are three or more consecutive frequency correction output sections with a masking compensation mark in the updated frequency output sequence. If the condition is met, execute the frequency masking adaptation switching process to 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 adaptation switching process; Mark the output result of the frequency measurement path after the frequency masking adaptation switching process as the alternative frequency measurement result under the geomagnetic disturbance environment and store it in the interference environment frequency response record sequence.

[0008] In a preferred embodiment, the prediction compensation module is used to extract all frequency jump position points from the alternative frequency measurement result and calculate the frequency jump error corresponding to each frequency jump position point to form a frequency jump error sequence; Determine whether there is an error segment in the frequency hopping error sequence where the error directions are the same and the time interval is less than a preset interval threshold. If the condition is met, mark this error segment as a frequency perturbation prediction template; otherwise, store the frequency hopping error sequence as a frequency measurement error record in the error cache. Use the time interval in the frequency perturbation prediction template as the prediction window period parameter, and use the end time index of the frequency perturbation prediction template as the starting point of the prediction window to generate a frequency masking prediction window. Use the time indices covered by the frequency masking prediction window to extract the corresponding time period in the original frequency response sequence. Construct a predicted frequency trajectory based on the frequency direction change trend extracted from the frequency perturbation prediction template, and store this predicted frequency trajectory in the frequency trajectory cache, marked as an advanced frequency recovery result generated based on perturbation prediction.

[0009] In a preferred embodiment, define in the identification and extraction module as a time segment Whether it is marked as a frequency masking response section; ; where is the frequency response value corresponding to the time point within the time segment ; is the amplitude response value corresponding to the time point within the time segment ; represents the frequency change speed; represents the amplitude change slope; is the time segment sampling time point set; 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; is the time segment center frequency; is the upper threshold of the center frequency; represents the time segment duration; is the duration threshold; is a logical decision function, and the logical decision function holds as 1, otherwise 0; represents the logical relation AND; represents all.

[0010] In a preferred embodiment, in the trajectory reconstruction module, define as the reconstructed frequency evolution trajectory at time The value on; ; ; where is an interpolation function, which is used to connect the frequency direction trend line and the connection points of the frequency trajectory to form a continuous trajectory; is the interpolation starting point; is the extension function of the frequency direction trend line before the frequency masking response section; is the extension function of the frequency direction trend line after the frequency masking response section; is the set of time indices for searching the interpolation starting point; represents the absolute value symbol; represents the time point corresponding to the lower limit of the difference; ; where is the function value of the extension function of the frequency direction trend line before the frequency masking response section at the interpolation starting point on; is the function value of the extension function of the frequency direction trend line after the frequency masking response section at the interpolation starting point on; In the formula, represents the product symbol; The linear weight function of the interpolation section is defined as: ; where is the duration of the interpolation transition interval; represents the condition range for the formula to hold.

[0011] In a preferred embodiment, the extension function of the frequency direction trend line before the frequency masking response section is expressed as: ; The extension function of the frequency direction trend line after the frequency masking response section is expressed as: ; where time the original frequency response value on; is the sliding time window width; In the formula, represents the product symbol; is the second derivative of the frequency response with respect to time; represents the coefficient of the second derivative of the frequency response in the trend line before the masking section; represents the suppression coefficient of the second derivative of the frequency response in the trend line after the masking section; is the exponential decay factor in the time direction before the masking section; is the exponential weighting factor in the time direction after the masking section; Exponential decay function.

[0012] In a preferred embodiment, in the path switching module, it is defined that represents at time judges whether to use the recovery result to replace the original result; ; ; ; where is the value of the original frequency response sequence at time ; is the value of the target frequency recovery result at time ; is the frequency difference substitution threshold; is the updated frequency output value; is the th frequency correction output section with a masking compensation mark; represents the total number of correction sections in the current judgment period; represents whether to trigger path switching, where 1 is for switching and 0 is for maintaining; is a logical decision function, and the logical decision function holds as 1, otherwise as 0; in the formula represents the product symbol; represents the absolute value symbol.

[0013] In a preferred embodiment, it is defined in the prediction compensation module that is the set of time points in the prediction template; ; ; where is the time index of the th jump error; is the numerical value of the frequency jump error at time ; represents 's sign, taking the value of +1 when , taking the value of -1 when , and taking the value of 0 when ; is the upper threshold of the time interval; represents the predicted frequency recovery result at time ; represents a frequency prediction trajectory generation function constructed based on a prediction template and a fitting trend function; represents a frequency direction change function obtained by fitting historical trends; is a set symbol, representing all that satisfy the conditions represents the logical relation AND.

[0014] Technical effects and advantages of the present invention: Aiming at the problem that weak continuous wave signals in space electromagnetic tomography tasks are easily masked by the geomagnetic disturbance background and cannot be demodulated by traditional frequency measurement structures, the present invention constructs a low-frequency disturbance response extraction mechanism in the electromagnetic frequency measurement process through a joint threshold recognition mechanism of frequency change speed and amplitude change slope, and can determine the shielding section without simply relying on the center frequency, thereby effectively restoring the blind zone signals in the frequency measurement channel; By analyzing the frequency increment inversion behavior in the identified frequency shielding response section, performing fitting of the front and back trend lines and interpolation calculation of the connection points, a complete frequency evolution trajectory is constructed, which can restore the truncated frequency measurement path in the case of non-linear jump, and improve the trajectory integrity and time consistency under continuous frequency measurement; Adopting a difference comparison between the target frequency recovery result and the original frequency measurement result and a cumulative judgment strategy for the frequency correction output section, designing the trigger conditions for multi-segment shielding compensation marks, and realizing dynamic frequency measurement path replacement on the premise of avoiding path oscillation, effectively enhancing the adaptive robustness of the frequency measurement output in the electromagnetic disturbance environment; By analyzing the time distribution and direction trend of frequency jump errors, constructing a disturbance prediction template and a frequency shielding prediction window, generating a predicted frequency trajectory before entering the shielding state, and forming a prediction compensation path based on the disturbance behavior pattern, improving the frequency measurement early warning and early modeling ability of the frequency measurement processing system in periodic interference scenarios. Brief description of the drawings

[0015] Figure 1 is a schematic diagram of the system module of the present invention. Detailed implementation manners

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] Refer to the accompanying specification 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; The identification and extraction module is used to divide the original radio frequency data stream into equal-length time segments, extract the frequency response sequence in each time segment, and mark the time segments that meet the conditions as frequency masking response sections according to the judgment results of the thresholds of the frequency change speed and the amplitude change slope; The trajectory reconstruction module is used to extract and judge the frequency direction jump trend in the frequency masking response section of the disturbance response description data, construct frequency trajectory connection points by fitting the frequency direction trend line, and interpolate and complete the frequency trajectory connection points into a continuous frequency evolution trajectory to form a 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 segments that meet the conditions according to the judgment results of the frequency difference sequence, and determine whether to perform a frequency measurement path switch through the masking compensation mark to generate an alternative frequency measurement result in the geomagnetic disturbance environment; The prediction and 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.

[0018] 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-length time segments and discretely extract the frequency response in each time segment; Calculate the frequency change speed and the amplitude change slope of the frequency response sequence extracted in each time segment as the quantitative expression of the frequency behavior in this time segment; Judge whether the frequency change speed is within the preset frequency change speed threshold range at not less than three consecutive time points, and the amplitude change slope is within the preset amplitude change slope threshold range at the corresponding not less than three consecutive time points. If satisfied, mark this time segment as a frequency slow change response section, otherwise skip the current time segment and continue to process the next time segment; Judge whether the center frequency of the frequency slow change response section is less than the preset center frequency threshold, and whether the duration of this frequency slow change response section is greater than the preset duration threshold. If both are satisfied, mark it as a frequency masking response section, otherwise skip the current frequency slow change response section, do not mark it as a frequency masking response section, and continue to process the next time segment; After the marking is completed, output the time index, center frequency, frequency change speed, and amplitude change slope of the frequency masking response section as disturbance response description data.

[0019] The trajectory reconstruction module is used to extract the frequency-direction jump trend of each frequency masking response section 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 of the frequency increment direction within a continuous time interval is greater than the preset reversal number threshold. If the condition is met, mark this change segment as a suspected frequency evolution inflection point area; otherwise, mark this frequency masking response section as having no trajectory jump feature and terminate the subsequent 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 section and the frequency direction trend line after the masking section respectively; extend the frequency direction trend line before the masking section backward according to its termination time to a preset specified fitting time interval, and extend the frequency direction trend line after the masking section forward according to its start time to a preset specified fitting time interval. Search for the intersection position point of the lower limit of the frequency difference within the overlapping extended interval of the two frequency direction trend lines as the frequency trajectory connection point of the frequency masking response section; Through the fitting functions of the frequency trajectory connection point and the frequency direction trend lines on both sides of the frequency masking response section, interpolate and complete the frequency trajectory connection point into a continuous frequency evolution trajectory as the target frequency recovery result.

[0020] 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 is a frequency difference within a continuous time segment in the frequency difference sequence that is greater than the preset tolerance threshold. If so, replace the original frequency response sequence with the target frequency recovery result within this time segment to form an updated frequency output sequence; Match the updated frequency output sequence with the time index of the frequency masking response section to generate a frequency correction output section with a masking compensation mark; Determine whether there are three or more consecutive frequency correction output sections with masking compensation marks in the updated frequency output sequence. If the condition is met, execute the frequency masking adaptation switching process to 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 adaptation switching process; Mark the output result of the frequency measurement path after the frequency masking adaptation switching process as the alternative frequency measurement result in the geomagnetic disturbance environment and store it in the interference environment frequency response record sequence.

[0021] The prediction compensation module is used to extract all frequency jump position points from the alternative frequency measurement result, and calculate the frequency jump error corresponding to each frequency jump position point to form a frequency jump error sequence; Determine whether there is an error segment with consistent error direction and time interval less than a preset interval threshold in the frequency hopping error sequence. If the condition is 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 cache. 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, and the predicted frequency trajectory is constructed according to 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.

[0022] It should be noted that in the formula structure involved in this scheme, dimensionless terms can be used as proportional or structural adjustment factors. When combined with quantities with units, they only play a role in numerical scaling and do not introduce new physical dimensions. Therefore, they will not change or confuse the unit system of the overall expression. This combination of "dimensionless terms and unit terms" can be understood as a composite structural expression commonly used in mathematical and physical modeling, which conforms to the principle of dimensional consistency and has a clear physical interpretation basis. 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 form a unified structure through function mapping, ratio combination or normalization adjustment, with clear units and meanings, and the overall expression conforms to the principle of dimensional consistency and the common formula of engineering modeling; In this solution, if constants, weights, adjustment factors, threshold parameters, proportional coefficients, etc. are designed, they are all adjustable control parameters for different application environments. Their values ​​depend on the target device configuration, data input characteristics and performance optimization goals. They are set within a reasonable range through model verification, performance constraints or engineering calibration during the implementation phase. Although such parameters do not have a unique preset value, they have clear adjustment logic and calculation path, and belong to the deterministic setting process in engineering implementation. The purpose of such setting is to ensure that the solution is both universally adaptable and reproducible and operable, without affecting its technical clarity and feasibility. Defined in the recognition extraction module For time segment Whether to mark it as a frequency masking response segment (1 for yes, 0 for no); ; in For time segment Internal time point The corresponding frequency response value; is a time segment The time point within The corresponding amplitude response value; represents the frequency change rate (derivative with respect to time); represents the amplitude change slope (derivative with respect to time); is a time segment The set of sampling time points of is the lower threshold of the frequency change rate; is the upper threshold of the frequency change rate; is the lower threshold of the amplitude change slope; is the upper threshold of the amplitude change slope; In this time segment On the premise that it is recognized as a frequency slowly varying response section, is a time segment The center frequency of is the upper threshold of the center frequency; In this time segment On the premise that it is recognized as a frequency slowly varying response section, represents the time segment The duration of is the duration threshold; is a logical decision function, the logical decision function holds as 1, otherwise 0; represents the logical relation AND; represents all, used to express that each element in the set satisfies a certain condition.

[0023] In the trajectory reconstruction module, define as the value of the reconstructed frequency evolution trajectory at time ; ; ; where is an interpolation function, and the interpolation function 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, and the interpolation starting point is the time point corresponding to the minimum difference between the two frequency direction trend line functions within the search interval; is the frequency direction trend line extension function before the frequency masking response section; is the frequency direction trend line extension function after the frequency masking response section; is the set of time indices for searching the interpolation starting point; represents the absolute value symbol; represents taking the time point corresponding to the lower limit of the difference; ; wherein is the function value of the frequency-direction trend line extension function before the frequency masking response section at the interpolation starting point ; is the function value of the frequency-direction trend line extension function after the frequency masking response section at the interpolation starting point ; in the formula, represents the product symbol; the linear weight function of the interpolation section is defined as: ; wherein is the duration of the interpolation transition interval; represents the condition range for the formula to hold, which is used to limit the formula to be valid for variables within a specific interval.

[0024] The frequency-direction trend line extension function before the frequency masking response section is expressed as: ; The frequency-direction trend line extension function after the frequency masking response section is expressed as: ; wherein time is the original frequency response value at; additionally, in the above formula, time represents the time point of the current calculated trend, and time represents the time point used to traverse within the integration window; is the sliding time window width, and the sliding time window width is used to construct the trend interval; in the formula, represents the product symbol; is the second derivative of the frequency response with respect to time, and the second derivative of the frequency response with respect to time represents the change acceleration, which is used to judge the trend smoothness or abruptness; represents the enhancement coefficient of the second derivative of the frequency response in the trend line before the masking section. The enhancement coefficient of the second derivative of the frequency response in the trend line before the masking section is used to highlight the rapid inflection point changes in the trajectory before masking. In practical applications, its value can be combined with the steepness of the frequency response change in the historical interval. When the response curvature fluctuates significantly, a larger value should be taken, and when the response is relatively gentle, it should be appropriately reduced to avoid overfitting; Denote the suppression coefficient of the second derivative of the frequency response in the trend line after the masking section. The suppression coefficient of the second derivative of the frequency response in the trend line after the masking section is used to smooth the trend change after the transition section and prevent local violent perturbations from misleading the fitting result. 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 when the fluctuation pattern is clear, the restriction can be relaxed; Is the exponential decay factor in the time direction before the masking section. The exponential decay factor in the time direction before the masking section is used to determine the retention degree of historical frequency response values in trend calculation. Its value can be adjusted according to the historical time window covered by trend analysis. If the historical trajectory information is more critical, the decay rate should be slowed down. If only the short-term direction needs to be captured, the decay speed can be increased to improve responsiveness; Is the exponential weighting factor in the time direction after the masking section. The exponential weighting factor in the time direction after the masking section is used to control the attention degree of frequency trend modeling to the newly arrived response points. Its value can be determined according to the predictability of the frequency trend after the masking section. When the trend continuity is strong, the weighting intensity is appropriately increased. When the trend is uncertain or the oscillation is strong, the weighting should be kept gentle to prevent introducing errors; Exponential decay function. In the above formula, the exponential decay function is used to simulate the decreasing sensitivity to the distance in time; In addition, the formula structure in the above formula is as follows: Denote in the interval The continuous integral of the variable Is used to reflect the trend accumulation.

[0025] In the path switching module, define Denote at time Judge whether to use the recovery result to replace the original result (1 for replacement, 0 for retention); ; ; ; Among them Is the value of the original frequency response sequence at time ; Is the value of the target frequency recovery result at time ; Is the frequency difference replacement threshold; Is the updated frequency output value; Is the th frequency correction output section with masking compensation mark; Denote the total number of correction sections in the current judgment period; Denote whether to trigger path switching, where 1 is for switching and 0 is for maintaining; is a logical decision function. If the logical decision function holds, it is 1; otherwise, it is 0. In the formula, represents the symbol of successive multiplication; represents the absolute value symbol.

[0026] is defined in the prediction compensation module as the set of time points in the prediction template; ; ; where is the time index of the th jump error; is the value of the frequency jump error at time ; represents 's sign. When , it takes the value of +1. When , it takes the value of -1. When , it takes the value of 0; is the upper threshold of the time interval; represents the predicted frequency recovery result at time ; 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; is the set symbol, representing the set composed of all that satisfy the conditions; represents the logical relation AND.

[0027] It should be noted as a whole that the technical solution of the present invention aims at the problem of the frequency measurement blind area caused by the frequency masking phenomenon of weak radio frequency signals due to geomagnetic disturbances in the orbital observation task. In the prior art, the commonly used frequency measurement model adopts a fixed frequency window or a linear filter structure, and cannot accurately restore the signal trajectory under strong background interference. Especially when non-linear jump behaviors such as interruption, drift or fallback occur in the frequency evolution process, the conventional means cannot determine whether the frequency continuity is truly interrupted or just masked by the background signal. The present invention is an application system architecture proposed with the core goal of "how to reconstruct the masked frequency trajectory". First, the recognition and extraction module is used to undertake the entry task of the solution, that is, to identify the time segments with frequency masking characteristics from the original RF data stream obtained by the microwave broadband instantaneous frequency measurement receiver; the reason for adopting the combined threshold judgment of "frequency change speed" and "amplitude change slope" in its execution logic is that during the frequency masking stage, the signal usually presents two characteristics: one is that the frequency fluctuation range narrows, and the other is that the amplitude change becomes stable; even if the weak signal has been "suppressed" by the background disturbance to near the frequency response baseline, the coherence of its local slope in the time dimension may still be retained; therefore, in the design, the frequency value itself is not used as the discrimination basis, but a composite threshold is established for the speed and direction of the change trend, so as to reduce the sensitivity to the amplitude and the offset of the center value; in addition, by further introducing the conditions of the center frequency and the duration, it is ensured that only those segments that maintain the masking characteristics within a sufficient time length are selected, and the transient anomalies formed by occasional interference are eliminated; After the preliminary recognition of the masking response section is completed, the core task of the trajectory reconstruction module is to judge whether there is an evolution trend of the frequency trajectory being interrupted, and to construct a continuous trajectory at the break point; the key point of the trajectory reconstruction module is not to simply fit the curve, but to determine whether there is a trend break from rising to falling or from falling to rising by analyzing the number of reversals of the frequency increment direction; in the real scenario, the frequency direction changes before and after the weak signal is masked are usually inconsistent. For example, a slowly rising target signal may quickly decline or stagnate after being "suppressed" by interference. Therefore, relying only on the extension of the trend line is prone to overfitting or misjudgment; therefore, this module designs a two-way fitting structure of the forward and backward trend lines, and sets a controllable fitting extension time range, and finds the minimum frequency difference point in the overlapping area of the two-sided trend lines as the trajectory connection point; essentially, it is to surround the masking section with the known trend, and infer the frequency change logic in the frequency area that is not directly observed, and finally reconstruct the masking section into a continuous trajectory with a fitting function, so as to restore the target frequency evolution path; The task of the path switching module is not only to output the recovery result, but to judge 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 recovery trajectory is that there may be trajectory inference errors in some frequency masking response sections, especially when the interference is extremely complex or the confidence 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 recovery trajectory and the original frequency measurement value; when the difference exceeds the preset tolerance threshold, the replacement operation is performed; further, to prevent path oscillation caused by isolated error segments, the path switching module constructs a "compensation mark cumulative judgment mechanism", and only when more than three frequency correction output sections appear continuously, the path switching is triggered; following the principle of "stability first", the continuity and stability of the original frequency measurement system are avoided from being damaged due to excessive response; The last prediction compensation module introduces the structure of the "frequency perturbation prediction template", which is proposed for the problem that frequency masking in long-term orbital operation tasks is periodic or predictable; since many geomagnetic perturbations have relatively regular behaviors, such as polar perturbations excited by the solar wind usually recurring at certain orbital altitudes, the direction of frequency jump error and time interval are extracted from historical alternative frequency measurement results, and an "error paragraph" is constructed to generate a prediction window in advance; once this prediction window covers the upcoming masking time period in the original frequency response sequence, a frequency trajectory can be directly constructed for early compensation without waiting for the masking section to be explicitly identified; this structure upgrades passive compensation to active prediction, which is also a forward-looking part in practical applications and is applicable to frequency measurement guarantee tasks in multi-orbit and long-duration operations.

[0028] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope 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 radio frequency data stream into equal-length time segments, extract the frequency response sequence in each time segment, and mark the time segments that meet the conditions as frequency masking response sections according to the judgment results of the thresholds of the frequency change speed and the amplitude change slope; The trajectory reconstruction module is used to extract and judge the frequency direction jump trend in the frequency masking response section of the disturbance response description data, construct frequency trajectory connection points by fitting the frequency direction trend line, and complete the frequency trajectory connection points into a continuous frequency evolution trajectory by interpolation 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 segments that meet the conditions according to the judgment result of the frequency difference sequence, and determine whether to perform frequency measurement path switching through the masking compensation mark to generate an alternative frequency measurement result under the geomagnetic disturbance environment; The prediction and 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, and construct a predicted frequency trajectory according to the frequency direction change trend to 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-length time segments, and discretely extract the frequency response in each time segment; Calculate the frequency change speed and the amplitude change slope of the frequency response sequence extracted in each time segment as the quantitative expression of the frequency behavior in this time segment; Judge whether the frequency change speed is within the preset frequency change speed threshold range at not less than three consecutive time points, and the amplitude change slope is within the preset amplitude change slope threshold range at the corresponding not less than three consecutive time points. If satisfied, mark this time segment as a frequency slow change response section, otherwise skip the current time segment and continue to process the next time segment; Judge whether the center frequency of the frequency slow change response section is less than the preset center frequency threshold, and whether the duration of the frequency slow change response section is greater than the preset duration threshold. If both are satisfied, mark it as a frequency masking response section, otherwise skip the current frequency slow change response section, do not mark it as a frequency masking response section, and continue to process the next time segment; After the marking is completed, output the time index, center frequency, frequency change speed, and amplitude change slope of the frequency masking response section as the 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 in each frequency masking response section of 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 of the frequency increment direction within a continuous time interval is greater than the preset reversal number threshold. If the condition is met, mark this change segment as a suspected frequency evolution inflection point area; otherwise, mark this frequency masking response section as having no trajectory jump feature and terminate; 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 section and the frequency direction trend line after the masking section respectively. Extend the frequency direction trend line before the masking section backward to the preset specified fitting time interval according to its termination time, and extend the frequency direction trend line after the masking section forward to the preset specified fitting time interval according to its start time. Search for the intersection position point of the lower limit of the frequency difference within the overlapping extended interval of the two frequency direction trend lines as the frequency trajectory connection point of the frequency masking response section; Through the fitting functions of the frequency trajectory connection point and the frequency direction trend lines on both sides of the frequency masking response section, interpolate and complete the frequency trajectory connection point into 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, wherein: 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 is a frequency difference within a continuous time segment in the frequency difference sequence that is greater than the preset tolerance threshold. If it is met, replace the original frequency response sequence with the target frequency recovery result within this time segment to form an updated frequency output sequence; Match the updated frequency output sequence with the time index of the frequency masking response section to generate a frequency correction output section with a masking compensation mark; Determine whether there are more than three consecutive frequency correction output sections with a masking compensation mark in the updated frequency output sequence. If the condition is met, execute the frequency masking adaptation 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 adaptation switching process; Mark the output result of the frequency measurement path after the frequency masking adaptation switching process as the alternative frequency measurement result in the geomagnetic disturbance environment and store it 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, wherein: The prediction compensation module is used to extract all frequency jump position points from the alternative frequency measurement result and calculate the frequency jump error corresponding to each frequency jump position point to form a frequency jump error sequence; Determine whether there is an error paragraph in the frequency jump error sequence where the error directions are the same and the time interval is less than the preset interval threshold. If the condition is met, mark this error paragraph as a frequency disturbance prediction template; otherwise, store the frequency jump error sequence as a frequency measurement error record in the error cache; Use the time interval in the frequency perturbation prediction template as the prediction window period parameter, and use the end time index of the frequency perturbation prediction template as the starting point of the prediction window to generate a frequency masking prediction window; Use the time indices covered by the frequency masking prediction window to extract the corresponding time period in the original frequency response sequence. Construct a predicted frequency trajectory based on the frequency direction change trend extracted from the frequency perturbation prediction template, and store this predicted frequency trajectory in the frequency trajectory cache, marked as the early frequency recovery result generated based on perturbation prediction.

6. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 5, wherein: Define in the recognition and extraction module as a time segment whether it is marked as a frequency masking response section; ； wherein is a time segment is a time point within it and the corresponding frequency response value; is a time segment is a time point within it and the corresponding amplitude response value; represents the frequency change rate; represents the amplitude change slope; is a time segment and the set of sampling time points of it; is the lower threshold of the frequency change rate; is the upper threshold of the frequency change rate; is the lower threshold of the amplitude change slope; is the upper threshold of the amplitude change slope; is a time segment and its center frequency; is the upper threshold of the center frequency; represents the time segment and its duration; is the duration threshold; is a logical decision function, which is 1 when the logical decision function holds, otherwise 0; represents the logical relation AND; represents all.

7. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 6, wherein: In the trajectory reconstruction module, it is defined that is the value of the reconstructed frequency evolution trajectory at time ; ； ； Among them is an interpolation function, which is used to connect the frequency-direction trend line and the connection points of the frequency trajectory to form a continuous trajectory; is the interpolation starting point; is the extension function of the frequency-direction trend line before the frequency masking response section; is the extension function of the frequency-direction trend line after the frequency masking response section; is the set of time indices for searching the interpolation starting point; represents the absolute value symbol; represents the time point corresponding to the lower limit of the difference; ； wherein is the function value of the frequency direction trend line extension function before the frequency masking response section at the interpolation starting point ; is the function value of the frequency direction trend line extension function after the frequency masking response section at the interpolation starting point ; in the formula, represents the product symbol; the linear weight function of the interpolation section is defined as: ； wherein is the duration of the interpolation transition interval; represents the conditional range for the formula to hold.

8. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 7, wherein: Frequency direction trend line extension function before the frequency masking response section Expressed as: ； Frequency direction trend line extension function after the frequency masking response section Expressed as: ； wherein time original frequency response value at; is the sliding time window width; in the formula represents the product symbol; is the second derivative of the frequency response with respect to time; represents the coefficient of the second derivative of the frequency response in the trend line before the masking section; represents the suppression coefficient of the second derivative of the frequency response in the trend line after the masking section; is the exponential decay factor in the time direction before the masking section; is the exponential weighting factor in the time direction after the masking section; exponential decay function.

9. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 8, wherein: In the path switching module, it is defined that indicates that at time it is judged whether to use the recovery result to replace the original result; ； ； ； where is the value of the original frequency response sequence at time ; is the value of the target frequency recovery result at time ; is the frequency difference substitution threshold; is the updated frequency output value; is the th frequency correction output section with a masking compensation mark; represents the total number of correction sections in the current judgment period; represents whether to trigger path switching, where 1 is for switching and 0 is for maintaining; is a logical decision function, and the logical decision function holds as 1, otherwise as 0; in the formula, represents the product symbol; represents the absolute value symbol.

10. The radio frequency signal processing system based on a microwave broadband instantaneous frequency measurement receiver according to claim 9, wherein: Define in the prediction compensation module as the set of time points in the prediction template; ； ； wherein is the time index of the th jump error; is the value of the frequency jump error at time ; represents the sign, which takes the value of +1 when , -1 when , and 0 when ; is the upper threshold of the time interval; represents the predicted frequency recovery result at time ; 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; is the set symbol, representing the set composed of all that satisfy the conditions; represents the logical relation AND.

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