Impulse interference suppression method and apparatus

Abstract

The application relates to the technical field of radio communication, and provides a pulse interference suppression method and device. The method comprises the following steps: collecting digital sampling signals transmitted in a preset time period; determining a non-interference signal threshold according to the amplitude of the digital sampling signals; performing pulse interference detection on the digital sampling signals according to the non-interference signal threshold; in the case that pulse interference exists, performing a preset pulse interference suppression measure to suppress the pulse interference in the digital sampling signals; and based on the suppressed digital sampling signals, redetermining the non-interference signal threshold, and reperforming pulse interference detection and pulse interference suppression until the digital sampling signals are outputted in the case that no pulse interference exists. The pulse interference suppression method and device can dynamically determine the non-interference signal threshold according to the amplitude of the signals, so as to improve the pulse interference detection accuracy, and through the multi-stage pulse interference detection and suppression mode, the pulse interference detection and suppression accuracy is further improved.

Description

Technical Field

[0001] This application relates to the field of radio communication technology, and in particular to a pulse interference suppression method and apparatus. Background Technology

[0002] During the transmission of wireless measurement and control signals, the signal transmission link is susceptible to various types of radio frequency interference. Among them, pulse interference, due to its concentrated energy and short bursts, poses a significant threat to the quality of the received signal, which can lead to signal distortion or even communication link interruption. Therefore, it is necessary to suppress pulse interference in the received signal.

[0003] In related technologies, impulse interference suppression often uses a fixed threshold as the criterion for impulse interference detection, and signals exceeding the threshold are identified as impulse interference and suppressed.

[0004] However, this fixed threshold method cannot adapt to the dynamic changes in signal amplitude, which can easily lead to missed or incorrect detection of pulse interference, making it difficult to meet the high precision requirements of the measurement and control communication system for signal anti-interference. Summary of the Invention

[0005] In view of this, this application aims to propose a pulse interference suppression method to improve the accuracy of pulse interference detection.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows: a pulse interference suppression method, comprising: acquiring digital sampling signals transmitted within a preset time period; determining an interference-free signal threshold based on the amplitude of the digital sampling signals; performing pulse interference detection on the digital sampling signals based on the interference-free signal threshold; in the presence of pulse interference, implementing preset pulse interference suppression measures to suppress pulse interference in the digital sampling signals; based on the suppressed digital sampling signals, re-determining the interference-free signal threshold, and re-performing pulse interference detection and pulse interference suppression until no pulse interference exists in the digital sampling signals, and then outputting the digital sampling signals.

[0007] Furthermore, the digital sampling signal includes multiple baseband signals; wherein, determining the interference-free signal threshold includes: calculating the variance of the signal amplitude of each baseband signal in the digital sampling signal; calculating the long-term signal amplitude mean of the digital sampling signal based on the variance; and calculating the interference-free signal threshold based on a preset threshold requirement and the long-term signal amplitude mean.

[0008] Furthermore, the formula for calculating the long-term signal amplitude mean includes: Where μ is the long-term average signal amplitude; z is the fundamental frequency signal amplitude; and f(z) is the amplitude probability density function of the fundamental frequency signal in the absence of pulse interference. The variance of the signal amplitude of each of the fundamental frequency signals in the digital sampled signal.

[0009] Furthermore, the process of determining the preset threshold requirement includes: determining the probability that the signal amplitude of the baseband signal is less than the preset threshold based on the amplitude probability density function of the baseband signal under no pulse interference; and determining the preset threshold requirement based on the probability that the signal amplitude of the baseband signal is less than the preset threshold.

[0010] Furthermore, the formula for calculating the probability that the amplitude of the baseband signal is less than a preset threshold includes: ;in, Where T is the preset threshold, F(T) is the probability that the amplitude of the baseband signal is less than the preset threshold, z is the amplitude of the baseband signal, and f(z) is the amplitude probability density function of the baseband signal in the absence of pulse interference. The variance of the signal amplitude of each of the fundamental frequency signals in the digital sampled signal.

[0011] Furthermore, the digital sampling signal includes multiple baseband signals; wherein, the step of performing pulse interference detection on the digital sampling signal based on the interference-free signal threshold includes: comparing each of the baseband signals with the interference-free signal threshold; if there is a baseband signal whose signal amplitude exceeds the interference-free signal threshold among the baseband signals, then it is determined that pulse interference exists in the baseband signal; when the signal amplitude of each of the baseband signals is not greater than the interference-free signal threshold, it is determined that there is no pulse interference in the digital sampling signal.

[0012] Furthermore, the step of performing preset pulse interference suppression measures in the presence of pulse interference includes: when the signal amplitude of at least one of the baseband signals exceeds the interference-free signal threshold, the at least one baseband signal is set to zero.

[0013] Furthermore, the acquisition of digital sampling signals transmitted within a preset time period includes: performing a first-stage down-conversion process on the radio frequency analog signals received within the preset time period to obtain intermediate frequency analog signals; performing an analog-to-digital conversion operation on the intermediate frequency analog signals according to a preset sampling rate to obtain digital intermediate frequency signals with a preset number of sampling points; and performing a second-stage down-conversion process on each of the digital intermediate frequency signals to obtain the digital sampling signals transmitted within the preset time period.

[0014] Furthermore, the digital sampling signal includes multiple baseband signals; wherein, determining the interference-free signal threshold based on the amplitude of the digital sampling signal includes: calculating the average amplitude of each of the baseband signals in the digital sampling signal; using the average amplitude to perform DC-free processing on the digital sampling signal to obtain a DC-free digital sampling signal; and determining the interference-free signal threshold based on the amplitude of the DC-free digital sampling signal.

[0015] Compared with related technologies, this application has at least the following advantages:

[0016] The pulse interference suppression method described in this application detects pulse interference by determining the threshold for interference-free signals based on the amplitude of the digitally sampled signal, rather than by using a fixed threshold. Therefore, the threshold for interference-free signals can be determined by following the actual signal amplitude, so that the threshold for interference-free signals can fit the actual amplitude characteristics of the current signal. This effectively avoids the problems of missed interference detection or misjudgment of normal signals caused by a fixed threshold, thereby improving the accuracy of pulse interference detection.

[0017] Furthermore, the pulse interference suppression method of this application performs multi-level pulse interference suppression and detection on the signal through a multi-level pulse interference suppression process, and each level of pulse interference suppression redetermines the threshold for interference-free signals before pulse interference detection. This multi-level pulse interference detection and suppression process can avoid missed detections that occur during single pulse detection, thereby further improving the accuracy of pulse interference detection and the cleanliness of the final output digital sampled signal.

[0018] Meanwhile, in the impulse interference suppression method of this application, the process of determining the interference-free signal threshold is to determine the probability that the fundamental frequency is less than a preset threshold by using the amplitude probability density function of the signal under impulse interference-free conditions, and then determine the preset threshold based on this probability, thereby determining the interference-free signal threshold. That is, in the impulse interference suppression method of this application, statistical characteristics (variance, long-term signal amplitude mean) are used to quantify the fluctuation range of the interference-free signal, allowing the calculation of the interference-free signal threshold to better reflect the true statistical characteristics of the signal, rather than relying on empirical values, thereby significantly improving the accuracy of impulse interference detection.

[0019] Another objective of this application is to provide a pulse interference suppression device, which includes a processor and a memory; the memory is used to store a computer program; when the computer program is executed by the processor, it enables the implementation of the above-described pulse interference suppression method.

[0020] The pulse interference suppression device described in this application performs the pulse interference suppression method described above to suppress the signal multiple times until no pulse interference is detected before outputting. Furthermore, the threshold for the interference-free signal used for pulse interference detection is dynamically determined based on the actual signal amplitude characteristics, rather than a fixed threshold. This improves the accuracy of pulse interference detection. Moreover, through the multi-stage detection and suppression process, it avoids missed detections during single pulse detection, thereby improving the cleanliness of the final output digital sampled signal. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0022] Figure 1 This is a schematic flowchart of the pulse interference suppression method described in the embodiments of this application.

[0023] Figure 2 This is a schematic diagram of the process for removing DC bias from a signal in the pulse interference suppression method described in this application embodiment.

[0024] Figure 3 This is a schematic diagram illustrating the specific process of determining the threshold for an interference-free signal in the pulse interference suppression method described in this application embodiment.

[0025] Figure 4 This is a schematic diagram of the overall process of the pulse interference suppression method described in the embodiments of this application.

[0026] Figure 5 This is a schematic diagram of the single-stage pulse interference detection and suppression process in the pulse interference suppression method described in the embodiments of this application.

[0027] Figure 6 This is a schematic diagram of the pulse interference suppression device described in the embodiments of this application.

[0028] Explanation of reference numerals in the attached figures: 610, processor; 620, memory. Detailed Implementation

[0029] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0031] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0033] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0034] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0035] An embodiment of the first aspect of this application provides a pulse interference suppression method. This method determines an interference-free signal threshold based on the amplitude of a digital sampled signal. Pulse interference is then detected using this threshold, and the digital sampled signal containing pulse interference is suppressed, achieving one stage of pulse interference suppression. Subsequently, the interference-free signal threshold is recalculated based on the suppressed digital sampled signal, and pulse interference detection and suppression are repeated again and again, achieving multiple stages of pulse interference suppression until no pulse interference is detected in the digital sampled signal before output. Therefore, on the one hand, determining the interference-free signal threshold based on the signal amplitude improves the accuracy of pulse interference detection compared to a fixed threshold method; on the other hand, the multi-stage pulse interference suppression process identifies and eliminates pulse interference multiple times, avoiding missed detections in a single test and improving the cleanliness of the final output digital sampled signal.

[0036] The pulse interference suppression method of this embodiment can be used in various communication scenarios requiring interference resistance for the transmission of telemetry and control signals, such as in spaceborne telemetry and control transponders. For ease of description and understanding, subsequent embodiments will use spaceborne telemetry and control transponders as an example, but this does not mean that the application scenarios of the pulse interference suppression method of this embodiment are limited.

[0037] In related technologies, the onboard telemetry, tracking, and command (TT&C) transponder is one of the core airborne devices of a satellite. Installed on the satellite, it serves as the hub for two-way communication between the satellite and ground control stations. In other words, from the moment the satellite enters orbit until it performs its mission in orbit and until the mission ends, all telemetry, tracking, and command interactions with the ground are completed by this onboard TT&C transponder.

[0038] Specifically, the main function of the onboard telemetry and control transponder is to receive uplink telemetry and control signals transmitted by the ground telemetry and control station, thereby driving the satellite to perform corresponding tasks; it is also used to transmit downlink telemetry data back to the ground telemetry and control station, enabling the ground telemetry and control station to know the satellite's status. Therefore, the reliability of the onboard telemetry and control transponder directly affects the accuracy of the satellite's mission execution.

[0039] Due to the complexity of the ground electromagnetic environment, the satellite-to-ground telemetry, tracking, and command (TT&C) communication link is highly susceptible to various radio frequency (RF) interferences. Among these, pulse interference poses a significant threat to onboard TT&C and response systems due to its concentrated energy and ease of generation.

[0040] Impulse interference is a short-duration, high-power burst of radio frequency interference. Therefore, when receiving signals containing impulse interference, the signal receiver of the onboard telemetry and control transponder may experience circuit saturation or signal distortion due to this short-duration, high-power interference. Severe impulse interference can also cause interruptions in the telemetry and control communication link or a sharp increase in the bit error rate, thus affecting ground control of the satellite. Therefore, it is necessary to suppress impulse interference in the signals received by the onboard telemetry and control transponder (i.e., the aforementioned uplink telemetry and control signals).

[0041] In most related technologies, pulse interference suppression is achieved by pre-setting a fixed interference detection threshold, identifying signals exceeding the threshold as interference and filtering them.

[0042] However, this method cannot adapt to dynamic changes in signal amplitude, and is prone to problems such as missing interference detection due to excessively high threshold settings and false filtering of normal signals due to excessively low threshold settings. It is difficult to completely eliminate the impact of pulse interference on subsequent signal processing and cannot meet the high precision requirements of satellite telemetry and control transponders for signal anti-interference.

[0043] In view of this, in order to overcome the shortcomings of related technologies, the pulse interference suppression method in this embodiment combines... Figure 1In terms of overall design, it includes the following steps S110-S150.

[0044] Step S110: Collect the digital sampling signals transmitted within a preset time period.

[0045] The preset time period refers to the time period set in advance for signal acquisition. This period can be set according to the signal processing rate of the onboard telemetry and control transponder, etc.

[0046] Specifically, for the spaceborne telemetry and control transponder, the signals it receives are usually analog signals in the radio frequency band. Therefore, in step S110, the analog signals in the radio frequency band received within a preset time period need to be processed by down-conversion and analog-to-digital conversion to obtain digital signals of each base frequency band, that is, to obtain each base frequency signal.

[0047] The digital sampled signal within the preset time period includes the processed baseband signals. That is, the digital sampled signal refers to a series of discrete data points arranged in chronological order obtained after processing the received radio frequency analog signal through frequency down-conversion and analog-to-digital conversion. Each discrete data point is a baseband signal, and these baseband signals together constitute the digital sampled signal.

[0048] Specifically, during sampling, sampling points can be selected in powers of 2, meaning the number of extracted discrete data points is a power of 2, such as 512 or 1024. This allows for subsequent processing. For example, in the spaceborne telemetry and control transponder, when it is necessary to perform a Fast Fourier Transform on the signal after pulse interference suppression, setting the number of sampling points to a power of 2 can improve the computational efficiency of the subsequent Fast Fourier Transform, thereby reducing the hardware computational complexity and resource consumption of the spaceborne telemetry and control transponder.

[0049] Step S120: Determine the threshold for interference-free signals based on the amplitude of the digital sampling signal.

[0050] The amplitude of the digital sampled signal reflects the strength and magnitude of its energy.

[0051] Step S130: Based on the threshold of no interference signal, perform pulse interference detection on the digital sampling signal.

[0052] Specifically, the interference-free signal threshold refers to the numerical boundary determined based on the amplitude of the digitally sampled signal, used to distinguish between normal interference-free signals and signals containing pulse interference.

[0053] For each fundamental frequency signal in the digital sampling signal, if pulse interference is applied to the fundamental frequency signal, the fundamental frequency signal will exceed the limit. That is, if a fundamental frequency signal exceeds the limit, the digital sampling signal can be determined to contain pulse interference; if all fundamental frequency signals do not exceed the limit, it is determined that there is no pulse interference in the digital sampling signal.

[0054] In step S130, for each fundamental frequency signal in the digital sampling signal, the step of judging the magnitude of its amplitude relative to the interference-free signal threshold can be performed separately. If the amplitude of any fundamental frequency signal exceeds the interference-free signal threshold, it indicates that the fundamental frequency signal is a signal doped with pulse interference. If the amplitude of any fundamental frequency signal does not exceed the interference-free signal threshold, it indicates that the fundamental frequency signal is a signal without pulse interference.

[0055] Step S140: In the presence of pulse interference, execute preset pulse interference suppression measures to suppress pulse interference in the digital sampling signal.

[0056] Specifically, in step S140, if at least one base frequency signal in the digital sampling signal contains pulse interference, it indicates that pulse interference exists, and the preset pulse interference suppression measure is executed to suppress the pulse interference in the digital sampling signal.

[0057] In some embodiments, the preset interference suppression process may specifically involve setting the amplitude of at least one baseband signal to zero when the amplitude of at least one baseband signal exceeds the threshold for no interference signal.

[0058] More specifically, the fundamental frequency signal containing pulse interference is zeroed out, that is, the fundamental frequency signal containing pulse interference is removed to filter out the fundamental frequency signal containing pulse interference, thereby achieving pulse interference suppression. The fundamental frequency signal without pulse interference is not adjusted.

[0059] Step S150: Based on the suppressed digital sampling signal, redetermine the threshold for interference-free signal, and re-perform pulse interference detection and suppression until there is no pulse interference in the digital sampling signal, and then output the digital sampling signal.

[0060] Specifically, after the preset pulse interference suppression measures are executed in step S140, each base frequency signal with pulse interference is zeroed out to complete the first-level pulse suppression, and the remaining base frequency signals are used as the suppressed digital sampling signals.

[0061] Next, a second stage of pulse suppression is performed. Specifically, based on the remaining fundamental frequency signals (i.e., the suppressed digital sampled signals), a new interference-free signal threshold is determined. Then, based on the new interference-free signal threshold, it is determined whether pulse interference exists in each of the remaining fundamental frequency signals, thus determining whether pulse interference exists in the suppressed digital sampled signals. If pulse interference is present, the fundamental frequency signals with pulse interference are set to zero, completing the second stage of suppression.

[0062] Following this pattern, the third level of pulse interference suppression is then performed, and so on, until the Mth level of pulse suppression is performed. Based on the new interference-free signal threshold, it is determined that there is no pulse interference in any of the remaining fundamental frequency signals. In other words, when it is determined that there is no pulse interference in the digital sampled signal, the pulse interference suppression ends, and the final digital sampled signal is output.

[0063] It is worth noting that the pulse interference suppression method, which sets the baseband signal containing pulse interference to zero, will delete some signal. However, even after multiple levels of suppression, this method usually only results in a signal energy loss of 0.04dB-0.4dB. This energy loss usually does not affect the operation of the onboard telemetry and control transponder.

[0064] Therefore, through steps S110-S150, digital sampling signals transmitted over a preset time period are collected, and an interference-free signal threshold is determined based on the amplitude of the digital sampling signals. This threshold is then used to detect pulse interference, and if pulse interference is present, pulse interference suppression processing is performed to achieve one instance of pulse interference suppression. Afterward, the interference-free signal threshold is recalculated based on the suppressed digital sampling signals, and the detection and suppression are repeated multiple times to achieve multiple pulse interference suppressions until no pulse interference is detected before outputting.

[0065] On the one hand, in this embodiment, when performing pulse interference detection, the interference-free signal threshold is determined by the amplitude of the digitally sampled signal, rather than by using a fixed threshold. Therefore, the interference-free signal threshold can be determined by following the actual signal amplitude, so that the interference-free signal threshold can fit the actual amplitude characteristics of the current signal, effectively avoiding the problem of missed interference detection or misjudgment of normal signals caused by a fixed threshold, thereby improving the accuracy of pulse interference detection.

[0066] On the other hand, this embodiment also employs a multi-stage pulse interference suppression process, with each stage redefining the threshold for interference-free signals to perform pulse interference detection. This multi-stage detection and suppression process avoids missed detections that occur during single-pulse detection, thereby improving the cleanliness of the final output digital sampling signal.

[0067] Continue by Figure 1As shown, in some exemplary embodiments, step S110, which involves acquiring the digital sampling signals transmitted within a preset time period, may specifically include: performing a first-stage down-conversion process on the received radio frequency analog signals within the preset time period to obtain intermediate frequency analog signals; then performing an analog-to-digital conversion operation on the intermediate frequency analog signals according to a preset sampling rate to obtain digital intermediate frequency signals with a preset number of sampling points; and finally performing a second-stage down-conversion process on each digital intermediate frequency signal to obtain digital sampling signals.

[0068] The preset number of sampling points is the number of samples of the digital intermediate frequency signal obtained by analog-to-digital conversion of the intermediate frequency analog signal within a preset time period. It is usually set to an integer power of 2 to adapt to the subsequent digital signal processing (such as performing fast Fourier transform on the digital signal).

[0069] The preset sampling rate refers to the signal sampling frequency set in advance for analog-to-digital conversion, that is, the number of times the intermediate frequency analog signal is sampled per unit time, and the unit is Hz (times / second). It is determined by the preset number of sampling points and the preset time period.

[0070] The preset sampling rate is the ratio of the preset number of sampling points to the preset time period.

[0071] Specifically, in step S110, the radio frequency analog signal (i.e., the uplink telemetry and control signal, which is the signal sent from the ground to the satellite) received by the onboard telemetry and control transponder is usually an analog signal in the radio frequency band, with a frequency on the order of GHz.

[0072] In step S110, the radio frequency analog signal is first subjected to a first-level down-frequency processing to reduce the frequency of the GHz-level radio frequency analog signal to an intermediate frequency analog signal (intermediate frequency refers to a frequency of tens of MHz).

[0073] Next, an analog-to-digital conversion (ADC) operation is performed, that is, the continuously varying intermediate frequency analog signal is sampled according to a preset sampling rate to obtain a discrete digital signal, resulting in a digital intermediate frequency signal with a preset number of sampling points. This ADC operation can be specifically implemented by the ADC module (Analog-to-Digital Converter) within the onboard telemetry and control transponder.

[0074] Next, the digital intermediate frequency (IF) signal undergoes a two-stage down-conversion process. Specifically, the digital signal processing module of the onboard telemetry and control transponder uses digital down-conversion to reduce the IF signal to the baseband frequency, obtaining various baseband signals. This digital sampled signal includes these baseband signals, which serve as the input for subsequent pulse interference detection and suppression.

[0075] It is worth noting that the baseband signals obtained after the two-stage down-frequency processing include not only the effective signal S(n), but also the pulse interference signal J(n) and the channel noise signal N(n). The digital sampled signal will then need to be subjected to pulse interference detection and suppression.

[0076] Therefore, the radio frequency analog signal is first down-converted to obtain an intermediate frequency analog signal. Then, the intermediate frequency analog signal is converted from analog to digital according to a preset sampling rate to obtain a digital intermediate frequency signal with a preset number of sampling points. Finally, the digital intermediate frequency signal is down-converted to obtain a digital sampled signal. This solves the problem that high-frequency signals cannot be directly sampled and also realizes the conversion of the signal from the analog domain to the digital domain.

[0077] Continue by Figure 1 and combined Figure 2 As shown, in some exemplary embodiments, in step S120 above, determining the interference-free signal threshold based on the amplitude of the digital sampling signal may specifically include the following steps S121-S123.

[0078] Step S121: Calculate the average amplitude of each fundamental frequency signal in the digital sampled signal.

[0079] Step S122: Use the amplitude average to perform DC removal processing on the digital sampling signal to obtain a digital sampling signal without DC bias.

[0080] Among them, the amplitude mean refers to the arithmetic mean of the signal amplitudes of each base frequency signal in the digital sampled signal within a preset time period.

[0081] Specifically, digitally sampled signals often contain a fixed DC bias (not an effective component of the signal itself). DC bias refers to a fixed amplitude offset in each fundamental frequency signal, which manifests as the overall signal amplitude of all fundamental frequency signals being either too high or too low.

[0082] This type of DC bias is an unavoidable DC deviation introduced by the radio frequency receiving link and analog-to-digital conversion module of the onboard telemetry and control transponder. If this DC bias is not eliminated and the interference-free signal threshold is calculated based on the amplitude of the digital sampling signal containing the DC bias, the calculated interference-free signal threshold will deviate from the true value, which may ultimately lead to misjudgment or missed detection of pulse interference.

[0083] Therefore, in this embodiment, the digital sampling signal is first de-DC processed using steps S121-S122 to obtain each base frequency signal without DC bias, which is to say, the digital sampling signal without DC bias is obtained. Then, step S123 is executed to determine the interference-free signal threshold based on the amplitude of the digital sampling signal without DC bias.

[0084] Specifically, in steps S121 and S122, since the uplink telemetry and control signal transmitted by the spaceborne telemetry and control station is a modulated radio frequency AC signal, the digital sampled signal obtained after frequency down-sampling and sampling will have an amplitude that fluctuates symmetrically around 0 under ideal conditions of no DC bias and no pulse interference (the absolute values ​​and frequency of positive and negative amplitudes are basically equal). That is, the mean value of each baseband signal under the condition of no DC bias should be 0.

[0085] This DC bias is a fixed amplitude offset caused by hardware factors such as circuit zero drift and device characteristics. This value remains completely unchanged during signal acquisition and processing over a preset time period and is indiscriminately added to the signal amplitude of each baseband signal.

[0086] Therefore, in step S121, the signal amplitudes of all fundamental frequency signals within a preset time period are extracted, and the mean amplitude of each fundamental frequency signal in the digital sampled signal is calculated according to the mean calculation formula (the sum of all amplitudes divided by the number of sampling points). Then, in step S122, the mean amplitude is subtracted from each fundamental frequency signal to obtain the fundamental frequency signals after DC bias removal, thus completing the DC bias removal process of the digital sampled signal.

[0087] Step S123: Determine the interference-free signal threshold based on the amplitude of the digital sampling signal without DC bias.

[0088] Specifically, in step S123, the interference-free signal threshold is determined based on the amplitude of the digital sampling signal without DC bias. That is, the interference-free signal threshold is determined according to the signal amplitude of each fundamental frequency signal without DC bias.

[0089] Through steps S121-S123, the average amplitude of each fundamental frequency signal in the digital sampled signal within a preset time period is first calculated. Then, this average amplitude is used to perform DC removal processing on the digital sampled signal to obtain a digital sampled signal without DC bias. Finally, the interference-free signal threshold is determined based on the amplitude of the digital sampled signal without DC bias. DC bias causes the statistical characteristics of the signal amplitude to deviate from the true value, and DC removal processing can eliminate this deviation, making the subsequently calculated interference-free signal threshold more closely match the actual fluctuation of the signal, improving the accuracy of pulse interference detection, and avoiding misjudging DC bias as pulse interference.

[0090] Continue by Figures 1-2 and combined Figure 3 In some exemplary embodiments, the specific process of determining the interference-free signal threshold in the above embodiments may include the following steps S310-S330.

[0091] Step S310: Calculate the variance of the signal amplitude of each fundamental frequency signal in the digital sampled signal.

[0092] Step S320: Calculate the long-term mean amplitude of the digital sampled signal based on the variance.

[0093] Step S330: Calculate the interference-free signal threshold based on the preset threshold requirements and the long-term average signal amplitude.

[0094] Specifically, for a spaceborne telemetry and control transponder, in the absence of pulse interference, each baseband signal contains channel noise and satellite signal. The power of channel noise (N(n)) is usually much greater than that of satellite signal (S(n)). Therefore, the overall characteristics of satellite signal and channel noise are the statistical characteristics of channel noise, that is, Gaussian white noise characteristics.

[0095] That is, the sum of satellite signal and channel noise S(n)+N(n) can be approximated as Gaussian white noise. Gaussian white noise refers to random noise in which the instantaneous amplitude of the fundamental frequency signal follows a Gaussian (normal) distribution and the energy is uniformly distributed within the effective bandwidth of the signal.

[0096] Therefore, the signal amplitude of the fundamental frequency signal The signal amplitude follows a Rayleigh distribution, meaning that its amplitude fluctuations are not random but follow a fixed statistical law. The dispersion (variance) and long-term average level (long-term signal amplitude mean) of the amplitude are relatively stable and will not exhibit large-scale disorderly fluctuations. In contrast, pulse interference is sudden and instantaneous, and its amplitude will deviate significantly from this stable statistical range. Therefore, by comparing the signal amplitude of each fundamental frequency signal with the interference-free signal threshold determined based on the long-term signal amplitude mean, it can be determined whether there is a situation where the signal amplitude of the fundamental frequency signal deviates significantly from the normal level. If there is a significant deviation from the normal level, it is considered that pulse interference exists, thus enabling pulse interference detection.

[0097] That is, in this embodiment, the variance of the signal amplitude of each base frequency signal in the digital sampling signal within a preset time period is statistically analyzed in step S310, and then the long-term signal amplitude mean is calculated in step S320 to determine the dispersion and long-term average level of each base frequency signal within the preset time period. Then, in step S330, the interference-free signal threshold is calculated based on the long-term signal amplitude mean, and the interference-free signal threshold can be used for pulse interference detection.

[0098] Furthermore, in some embodiments, the preset threshold requirement is the signal amplitude of the baseband signal. It is determined based on the Rayleigh distribution. Specifically, the process of determining this preset threshold requirement includes: determining the probability that the amplitude of the fundamental frequency signal is less than the preset threshold based on the amplitude probability density function of the fundamental frequency signal under no pulse interference; and determining the preset threshold requirement based on the probability that the amplitude of the fundamental frequency signal is less than the preset threshold.

[0099] Specifically, in the absence of pulse interference, the amplitude of the fundamental frequency signal, i.e., S(n) + N(n), is denoted by z, where z = The signal follows a Rayleigh distribution. Therefore, the probability density function of z (that is, the amplitude probability density function of the fundamental frequency signal) can be expressed as Equation 1 below.

[0100] (Formula 1).

[0101] Where f(z) is the amplitude probability density function of the fundamental frequency signal in the absence of pulse interference. This represents the variance of the amplitude of the digitally sampled signal.

[0102] The amplitude probability density function reflects the probability distribution of the fundamental frequency signal amplitude in different value ranges under no-pulse interference conditions, and can accurately characterize the probability density features of each signal amplitude value.

[0103] The probability that the amplitude of the baseband signal is less than the preset threshold can be obtained by integrating the amplitude probability density function. Specifically, the formula for calculating the probability that the amplitude of the baseband signal is less than the preset threshold includes the following formula two.

[0104] (Formula 2).

[0105] Where T is the preset threshold, F(T) is the probability that the amplitude of the baseband signal is less than the preset threshold, and μ is the long-term average amplitude of the signal.

[0106] The formula for calculating the long-term signal amplitude mean includes the following formula three.

[0107] (Formula 3).

[0108] Using Formula 2 and Formula 3 above, we can obtain the relationship between the probability that the signal amplitude z of the fundamental frequency signal is less than the preset threshold T and the average amplitude of the long-term signal, as shown in Formula 4 below.

[0109] (Formula 4).

[0110] From Formula 4, we can further deduce:

[0111] (Formula 5).

[0112] According to Formula 5, it can be seen that, in the absence of pulse interference, the signal amplitude of the fundamental frequency signal... The probability that z is less than a certain preset threshold T is related to T / μ, which is also related to the ratio of the preset threshold T to the long-term signal amplitude mean.

[0113] Therefore, the ratio of T / μ can be adjusted, and a preset threshold T can be determined by combining it with the long-term average signal amplitude. This maximizes the probability that the signal amplitude z of the fundamental frequency signal is greater than the preset threshold T in the absence of pulse interference. By using the preset threshold T as the threshold for interference-free signals, fundamental frequency signals with signal amplitude z less than or equal to the preset threshold T can be filtered out. Fundamental frequency signals with amplitude z greater than the preset threshold T can be considered to have pulse interference.

[0114] For example, according to Formula 5, when T = 2μ, the probability that the amplitude z of the baseband signal without pulse interference is less than the preset threshold T is 95.7%; when T = 3μ, the probability that the amplitude z of the baseband signal without pulse interference is less than the preset threshold T is 99.91%. From the above analysis, it can be seen that when there is no pulse interference in the baseband signal received by the transponder, The probability of the amplitude being greater than 3μ is 0.0009. That is, under the significance level β=0.0009, the amplitude of the fundamental frequency signal being greater than 3μ is considered to be a low-probability event. In other words, when there is a case where the amplitude of the fundamental frequency signal is greater than 3μ, it can be considered that there is pulse interference in the fundamental frequency signal. Therefore, three times the long-term average signal amplitude is taken as the threshold of the interference-free signal.

[0115] In this way, by using statistical characteristics (variance, long-term signal amplitude mean) to quantify the fluctuation range of the interference-free signal, the calculation of the interference-free signal threshold can better reflect the true statistical characteristics of the signal, rather than relying on empirical values, thereby significantly improving the accuracy of subsequent pulse interference detection.

[0116] Additionally, it is worth noting that in step S320 above, when calculating the long-term signal amplitude mean based on the variance of the signal amplitude of each fundamental frequency signal in the digital sampling signal, it can be calculated according to formula three above.

[0117] In some embodiments, after determining the interference-free signal threshold, the interference-free signal threshold can be used to perform pulse interference detection on each base frequency signal in the digital sampling signal. Specifically, the magnitude of each base frequency signal is compared with the interference-free signal threshold.

[0118] If there is a baseband signal whose amplitude exceeds the threshold for no interference signal among all baseband signals, then it is determined that there is pulse interference in the baseband signal whose amplitude exceeds the threshold for no interference signal.

[0119] When the amplitude of each base frequency signal is not greater than the threshold of no interference signal, it is determined that there is no pulse interference in each base frequency signal, that is, there is no pulse interference in the digital sampling signal.

[0120] More specifically, when pulse interference is present in the signals received by the onboard telemetry and control transponder, the amplitude of the contaminated portion of the baseband signal will inevitably be relatively large. Meanwhile, the uncontaminated portion of the baseband signal still follows a Rayleigh distribution, and its amplitude remains no greater than the aforementioned threshold for interference-free signals. Therefore, pulse interference can be detected.

[0121] Therefore, the problem of impulse interference detection is transformed into a hypothesis testing problem. Hypothesis testing can be described as:

[0122] (Formula 6).

[0123] Based on the statistical characteristics of the fundamental frequency signal amplitude, the number of fundamental frequency signals whose amplitude is greater than the threshold of no interference signal is counted to obtain the verification statistic.

[0124] For example, the above analysis yields the signal amplitude of the fundamental frequency signal. The probability of a value greater than 3μ is 0.0009. Under the condition of no interference signal threshold of 3μ, the test statistic... .

[0125] The test statistic is the number of fundamental frequency signals whose amplitude is greater than the threshold for interference-free signals. When this test statistic... At that time, the above assumptions were considered If true, it means that there is no pulse interference in any of the fundamental frequency signals and no pulse interference in the digital sampling signals; otherwise, the assumption is considered true. This is valid; there is pulse interference in the digital sampling signal.

[0126] when At the time of establishment, it is assumed that there is no pulse interference in the signals received by the onboard telemetry and control transponder, and no action is taken at this time. If If the condition is met, then the digital sampled signal with an amplitude greater than the threshold of the interference-free signal is considered to have pulse interference.

[0127] Furthermore, if the amplitude of at least one baseband signal exceeds the threshold for interference-free signals, the at least one baseband signal is set to zero, thereby filtering out baseband signals with pulse interference in the digital sampled signal and achieving pulse interference suppression.

[0128] It is worth noting that, regarding the pulse interference suppression method of this embodiment, based on the above exemplary implementations, in specific implementation, as a preferred embodiment, it is still based on... Figure 1-3 and combined Figure 4 and Figure 5 As shown, it may include, for example:

[0129] Reference Figure 4After receiving the radio frequency analog signal through the antenna, the onboard telemetry and control transponder first reduces the frequency of the signal from the carrier frequency to the intermediate frequency through the radio frequency receiving channel. Then, the analog intermediate frequency signal is converted into a digital intermediate frequency signal by the ADC. Finally, the signal is digitally down-converted to generate various base frequency signals. Where S(n), J(n), and N(n) represent satellite signal, pulse interference, and noise, respectively, the digital sampling signal is obtained.

[0130] Then, the obtained baseband signals are temporarily stored in RAM (Random Access Memory), and the average amplitude of each baseband signal is calculated.

[0131] Then, each baseband signal stored in RAM is read, and the average amplitude of each baseband signal is subtracted to perform DC bias removal processing to obtain each baseband signal without DC bias.

[0132] Subsequently, multi-level pulse interference detection and suppression processing is performed based on each baseband signal without DC bias. Specifically, due to the randomness of the baseband signal and the fluctuation characteristics of the pulse interference envelope, the randomness of pulse interference occurrence, and the uncertainty of the pulse interference duty cycle, the probability of missed detection in a single interference detection and suppression is relatively high. To improve the detection probability, this embodiment adopts multi-level interference detection and suppression, wherein the number M of pulse interference detection and suppression is determined by the actual interference suppression effect.

[0133] The specific multi-stage pulse interference detection and suppression process includes: first, performing a first pulse interference detection and suppression, followed by a second pulse interference detection and suppression, and so on until the Mth pulse interference detection and suppression is performed. If no pulse interference is detected in the remaining fundamental frequency signals, the multi-stage pulse interference detection and suppression process ends, and the final fundamental frequency signals are output to the subsequent processing module for processing and output. Otherwise, the (M+1)th pulse interference detection and suppression continues until no pulse interference is detected. The subsequent processing module can be, for example, a phase-locked loop (PLL) or frequency-locked loop (FLL) tracking loop. It is worth noting that the subsequent processing module in this embodiment can use existing module products, which will not be elaborated further here.

[0134] More specifically, Figure 5 The process of single-stage pulse suppression is illustrated. (Refer to...) Figure 5 Taking the first-level pulse interference detection and suppression as an example, the base frequency signal without DC bias is first temporarily stored in RAM, and the long-term signal amplitude mean of each base frequency signal is calculated using Formula 3 above. Based on the ratio of the interference-free signal threshold obtained by Formula 5 above to the long-term signal amplitude mean, the interference-free signal threshold is calculated.

[0135] Then, the first pulse interference detection is performed. The signal amplitude of each temporarily stored baseband signal without DC bias is compared with the interference-free signal threshold. If the signal amplitude of a baseband signal exceeds the interference-free signal threshold, it is determined that the baseband signal carries pulse interference and is zeroed. If the signal amplitude of a baseband signal does not exceed the interference-free signal threshold, it is determined that it is a pulse-free signal and is retained. The first pulse interference detection and suppression is completed, and the baseband signals obtained after the first pulse interference detection and suppression are output.

[0136] Then, all remaining fundamental frequency signals after processing are extracted and used as the signal source for the next stage of detection and suppression. Based on the remaining fundamental frequency signals, the process is then repeated according to... Figure 5 The process shown involves using Formula 3 to calculate the new long-term signal amplitude mean, recalculating the new interference-free signal threshold, and then performing the second-level pulse interference detection and suppression.

[0137] Specifically, in the second-level pulse interference detection and suppression process, the updated interference-free signal threshold will be used as the criterion to perform a second pulse interference detection and suppression on the remaining baseband signal.

[0138] The above logic is executed repeatedly in this loop. Figure 5 The process is shown, and each level of interference detection and suppression is based on the remaining fundamental frequency signal after the previous level is zeroed out, the threshold for no interference signal is recalculated, and corresponding pulse interference detection is performed.

[0139] After each stage of pulse interference suppression processing is completed, during the next stage of pulse interference detection, the remaining baseband signals are used to determine pulse interference using a new interference-free signal threshold. If no baseband signal exceeding the interference-free signal threshold is detected in the digital sampled signal, it is determined that there is no pulse interference in the signal, the subsequent interference suppression process is terminated, and the remaining baseband signals are output as pulse interference suppression results to the subsequent processing module for further processing and output.

[0140] Conversely, if pulse interference is still detected, the next level of threshold update, pulse interference detection and suppression operation is performed until it is determined that there is no pulse interference in the digital sampled signal.

[0141] In the preferred embodiment of the above pulse interference suppression method, the specific implementation methods of each step can still be found in the descriptions of the above exemplary embodiments. Furthermore, the beneficial effects brought about by the design of each step in this preferred embodiment can also be found in the descriptions of the above exemplary embodiments, and will not be repeated here.

[0142] An embodiment of the second aspect of this application provides a pulse interference suppression device, referring to... Figure 6The pulse interference suppression device includes a processor 610 and a memory 620. The processor 610 and the memory 620 are connected, for example, via a bus. Optionally, the pulse interference suppression device may also include a transceiver. It should be noted that in practical applications, the transceiver is not limited to one unit, and the structure of this pulse interference suppression device does not constitute a limitation on the embodiments of this application.

[0143] The memory 620 is used to store application code that executes the solution of this application, and its execution is controlled by the processor 610. The processor 610 is used to execute the application code stored in the memory 620 to implement the content shown in the foregoing method embodiments.

[0144] The pulse interference suppression device in this embodiment can specifically be the aforementioned spaceborne telemetry and control transponder. This embodiment's pulse interference suppression device performs multiple pulse interference suppression operations on the signal until no pulse interference is detected before outputting. Furthermore, the interference-free signal threshold used for pulse interference detection is dynamically determined based on the actual signal amplitude characteristics, rather than a fixed threshold. This improves the accuracy of pulse interference detection. Moreover, the multi-stage detection and suppression process avoids missed detections during single pulse detection, thereby improving the cleanliness of the final output digital sampled signal.

[0145] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A method for suppressing impulse interference, characterized in that, The pulse interference suppression method includes: Collect digital sampling signals transmitted within a preset time period; Determine the interference-free signal threshold based on the amplitude of the digitally sampled signal; Based on the interference-free signal threshold, pulse interference detection is performed on the digital sampled signal; In the presence of pulse interference, a preset pulse interference suppression measure is implemented to suppress pulse interference in the digital sampling signal; Based on the suppressed digital sampling signal, the threshold for no interference signal is re-determined, and pulse interference detection and suppression are performed again until there is no pulse interference in the digital sampling signal, at which point the digital sampling signal is output. The digital sampling signal includes multiple baseband signals; the determination of the interference-free signal threshold includes: Calculate the variance of the signal amplitude of each fundamental frequency signal in the digital sampled signal; Calculate the long-term mean amplitude of the digital sampled signal based on the variance; The interference-free signal threshold is calculated based on the preset threshold requirements and the long-term average signal amplitude. The formula for calculating the long-term signal amplitude mean includes: ； Where μ is the long-term average signal amplitude; z is the fundamental frequency signal amplitude; and f(z) is the amplitude probability density function of the fundamental frequency signal under no pulse interference. The variance of the signal amplitude of each of the fundamental frequency signals in the digital sampled signal; The process for determining the preset threshold requirement includes: Based on the amplitude probability density function of the baseband signal under no pulse interference, determine the probability that the signal amplitude of the baseband signal is less than a preset threshold; The preset threshold requirement is determined based on the probability that the amplitude of the base frequency signal is less than the preset threshold. The step of implementing preset pulse interference suppression measures in the presence of pulse interference includes: If the amplitude of at least one of the baseband signals exceeds the interference-free signal threshold, the amplitude of the at least one baseband signal will be set to zero. The step of determining the interference-free signal threshold based on the amplitude of the digital sampled signal includes: Calculate the average amplitude of each of the fundamental frequency signals in the digital sampled signal; Using the amplitude average, the digital sampled signal is subjected to DC removal processing to obtain a digital sampled signal without DC bias; The interference-free signal threshold is determined based on the amplitude of the digital sampling signal without DC bias. Specifically, the step of redetermining the interference-free signal threshold based on the suppressed digital sampling signal, and re-performing pulse interference detection and suppression until no pulse interference exists in the digital sampling signal, before outputting the digital sampling signal, includes: After implementing the preset pulse interference suppression measures to zero out each fundamental frequency signal with pulse interference, the first-level pulse suppression is completed, and the remaining fundamental frequency signals are the suppressed digital sampled signals. Based on the remaining fundamental frequency signals, a new interference-free signal threshold is determined. Using this new threshold, it is determined whether pulse interference exists in each of the remaining fundamental frequency signals. If pulse interference exists, the fundamental frequency signal with pulse interference is set to zero to obtain the remaining fundamental frequency signals, thus completing the second stage of pulse suppression. Then, a new interference-free signal threshold is determined based on the remaining fundamental frequency signals, and the third stage of pulse interference suppression is performed. This process continues until the Mth stage of pulse interference suppression is performed. Based on the remaining fundamental frequency signals obtained after the Mth stage of pulse interference suppression, a new interference-free signal threshold is determined. Based on the new threshold, it is determined that there is no pulse interference in any of the remaining fundamental frequency signals obtained after the Mth stage of pulse interference suppression. The pulse interference suppression ends, and the remaining fundamental frequency signals are output as the final digital sampling signal.

2. The pulse interference suppression method according to claim 1, characterized in that, The formula for calculating the probability that the amplitude of the fundamental frequency signal is less than a preset threshold includes: ； in, ; Where T is the preset threshold, F(T) is the probability that the amplitude of the baseband signal is less than the preset threshold, z is the amplitude of the baseband signal, and f(z) is the amplitude probability density function of the baseband signal in the absence of pulse interference. The variance of the signal amplitude of each of the fundamental frequency signals in the digital sampled signal.

3. The pulse interference suppression method according to claim 1, characterized in that, The digital sampling signal includes multiple base frequency signals; The step of performing pulse interference detection on the digital sampled signal based on the interference-free signal threshold includes: Compare the magnitudes of each of the baseband signals with the threshold values ​​of the interference-free signal; If, among the various baseband signals, there is a baseband signal whose amplitude exceeds the threshold of the interference-free signal, then it is determined that there is pulse interference in the baseband signal. When the amplitude of each of the baseband signals is not greater than the interference-free signal threshold, it is determined that there is no pulse interference in the digital sampling signal.

4. The pulse interference suppression method according to claim 1, characterized in that, The acquisition of digital sampling signals transmitted within a preset time period includes: The received radio frequency analog signal within a preset time period is subjected to a first-level down-frequency processing to obtain an intermediate frequency analog signal; According to the preset sampling rate, the intermediate frequency analog signal is subjected to analog-to-digital conversion to obtain a digital intermediate frequency signal with a preset number of sampling points; Each of the digital intermediate frequency signals is subjected to a two-stage down-frequency processing to obtain the digital sampled signal transmitted within the preset time period.

5. A pulse interference suppression device, characterized in that, The pulse interference suppression device includes a processor and a memory; The memory is used to store computer programs; When the computer program is executed by the processor, it enables the pulse interference suppression method according to any one of claims 1-4.

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