Frequency domain equalization method, system, receiver and medium for GNSS anti-jam filter

Abstract

The application provides a frequency domain equalization method, system, receiver and medium of a GNSS anti-interference filter, and particularly relates to the technical field of GNSS interference signal suppression, and the method comprises the following steps: inputting the collected intermediate frequency signal of the GNSS signal into the anti-interference filter to obtain a filtered intermediate frequency signal; based on the tracking result output by the receiver baseband and a preset spectrum amplitude, the intermediate frequency signal is predicted and filtered to obtain a reference spectrum of an interference frequency band; based on a normal intermediate frequency signal, a reference spectrum of a non-interference frequency band is obtained; the reference spectrum of the non-interference frequency band and the reference spectrum of the interference frequency band are fused to obtain a complete reference spectrum, and then the filtered intermediate frequency signal is equalized to obtain an equalized GNSS signal. The method can significantly improve the signal distortion caused by the traditional anti-interference filter, thereby effectively improving the anti-interference performance of the GNSS, and further improving the quality of the signal output by the receiver.

Description

Technical Field

[0001] This invention relates to the field of GNSS interference signal suppression technology, and in particular to a frequency domain equalization method, system, receiver, and medium for a GNSS anti-interference filter. Background Technology

[0002] Currently, Global Navigation Satellite Systems (GNSS) play a crucial supporting role in the rapid development of global Internet of Things (IoT) and artificial intelligence (AI) technologies, and are widely used in smartphones, smartwatches, navigators, and drones. However, due to the relatively weak anti-jamming capabilities of GNSS systems, ensuring their reliability in interference-prone environments is particularly important.

[0003] In existing technologies, interference suppression typically employs GNSS interference signal filtering techniques. These techniques primarily rely on the analysis of data acquired by the GNSS front-end to reduce interference signals using appropriate filtering methods, such as adaptive notch filtering, frequency-domain adaptive filtering, and transform-domain filtering. While these interference filtering techniques effectively suppress the impact of interference signals on GNSS, useful GNSS signals within the interference frequency band are also filtered out. Therefore, GNSS anti-interference filtering techniques are prone to causing distortion or loss of useful GNSS signals, leading to a deterioration in GNSS signal quality and reduced GNSS performance.

[0004] Therefore, equalization techniques are commonly used in communication systems to mitigate signal distortion caused by channel propagation. Common equalization algorithms include linear equalization, decision feedback equalization, adaptive equalization, and blind equalization. These equalization techniques correct the waveform, amplitude, or phase of the signal through corresponding filtering or compensation techniques to match the corresponding characteristics of a reference model. The reference model is typically established based on the original transmitted signal model and channel characteristics. However, in real-world environments, the received GNSS signal is usually unknown, making it impossible to obtain the reference signal required for equalization. Therefore, traditional equalization techniques are difficult to use to compensate for distortion caused by GNSS interference, resulting in the inability to effectively improve signal distortion caused by traditional anti-interference filters and hindering the effective enhancement of GNSS anti-interference performance. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a frequency domain equalization method, system, receiver and medium for GNSS anti-interference filters, aiming to solve the problem that the signal distortion caused by traditional anti-interference filters cannot be effectively improved and the anti-interference performance of GNSS cannot be effectively enhanced.

[0006] To achieve the above objectives, the first aspect of the present invention provides a frequency domain equalization method for a GNSS anti-interference filter, comprising the following steps:

[0007] Based on the acquired GNSS signals, the intermediate frequency signal is obtained;

[0008] The intermediate frequency signal is input to an anti-interference filter to filter out signals in the interference frequency band of the intermediate frequency signal, thereby obtaining a filtered intermediate frequency signal;

[0009] Based on the tracking results of the receiver baseband output and the preset spectral amplitude, the intermediate frequency signal is predicted and filtered to obtain the reference spectrum of the interference band.

[0010] Obtain a normal intermediate frequency signal, and based on the normal intermediate frequency signal, obtain a reference spectrum of the interference-free frequency band;

[0011] The reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band are fused to obtain a complete reference spectrum;

[0012] Based on the complete reference spectrum, the filtered intermediate frequency signal is subjected to equalization processing to obtain the equalized GNSS signal.

[0013] Optionally, the step of predicting and filtering the intermediate frequency signal based on the tracking result of the receiver baseband output and a preset spectral amplitude to obtain a reference spectrum for the interference band includes:

[0014] Based on the tracking results of the receiver baseband output and the preset spectral amplitude, the intermediate frequency signal is predicted to obtain the predicted GNSS signal;

[0015] The predicted GNSS signal is input into the anti-interference filter to filter out signals in the interference frequency band of the predicted GNSS signal, thereby obtaining the filtered predicted signal.

[0016] Based on the predicted GNSS signal and the filtered predicted signal, a reference spectrum for the interference band is obtained.

[0017] Optionally, the step of inputting the intermediate frequency signal into an anti-interference filter to filter out signals in the interference frequency band of the intermediate frequency signal to obtain a filtered intermediate frequency signal includes:

[0018] The characteristics of the intermediate frequency signal are analyzed using the anti-interference filter to determine the frequency band of the interference signal and obtain the interference frequency band.

[0019] Based on the interference frequency band, the notch frequency of the anti-interference filter is adjusted, and the signal in the interference frequency band is filtered out based on the notch frequency to obtain the filtered time-domain signal.

[0020] Alternatively, by comparing the spectral amplitude of the intermediate frequency signal with a preset threshold value, the signal in the interference frequency band can be suppressed to obtain the filtered time-domain signal;

[0021] The filtered time-domain signal is subjected to Fourier transform to obtain the filtered intermediate frequency signal.

[0022] Optionally, the step of predicting the intermediate frequency signal based on the tracking result of the receiver baseband output and a preset spectral amplitude to obtain the predicted GNSS signal includes:

[0023] Obtain the code delay and code tracking error of the previous moment, and obtain the predicted code delay based on the code delay and the code tracking error;

[0024] Obtain the Doppler frequency offset and carrier frequency tracking error of the previous moment, and obtain the predicted Doppler frequency offset based on the Doppler frequency offset and the carrier frequency tracking error;

[0025] Obtain the phase and carrier phase tracking error of the previous moment, and obtain the predicted phase based on the phase and carrier phase tracking error;

[0026] Based on the tracking result of the receiver baseband output at the previous moment, the predicted navigation message is obtained;

[0027] The intermediate frequency signal is predicted based on the predicted code delay, the predicted Doppler frequency offset, the predicted phase, the predicted navigation message, and the preset spectral amplitude to obtain the predicted GNSS signal.

[0028] Optionally, obtaining the reference spectrum of the interference band based on the predicted GNSS signal and the filtered predicted signal includes:

[0029] Calculate the spectrum of the predicted GNSS signal and the spectrum of the filtered predicted signal;

[0030] The reference spectrum of the interference band is obtained based on the difference between the spectrum of the predicted GNSS signal and the spectrum of the filtered predicted signal.

[0031] Optionally, the step of equalizing the filtered intermediate frequency signal based on the complete reference spectrum to obtain the equalized GNSS signal includes:

[0032] Within the interference-free frequency band, the amplitude of the filtered intermediate frequency signal, the amplitude of the complete reference spectrum, and the initial value of the preset amplitude gain coefficient are obtained. The value of the amplitude gain coefficient is adjusted so that the absolute value of the difference between the amplitude of the filtered intermediate frequency signal and the amplitude of the complete reference spectrum is minimized, thereby obtaining the equalized frequency domain signal in the interference-free frequency band.

[0033] Within the interference frequency band, the reference spectrum of the filtered interference frequency band is compensated to the amplitude of the filtered intermediate frequency signal to obtain the equalized frequency domain signal in the interference frequency band.

[0034] Based on the equalized frequency domain signal in the interference-free frequency band and the equalized frequency domain signal in the interference frequency band, the equalized frequency domain signal is obtained.

[0035] The equalized frequency domain signal is subjected to inverse Fourier transform to obtain the equalized GNSS signal.

[0036] A second aspect of the present invention provides a frequency domain equalization system for a GNSS anti-interference filter, the system comprising:

[0037] The receiver front end is used to obtain the intermediate frequency signal based on the acquired GNSS signal;

[0038] An anti-interference filter module is used to input the intermediate frequency signal into an anti-interference filter, filter out signals in the interference frequency band of the intermediate frequency signal, and obtain a filtered intermediate frequency signal.

[0039] The interference band spectrum estimation module is used to predict and filter the intermediate frequency signal based on the tracking results of the receiver baseband output and the preset spectrum amplitude to obtain the reference spectrum of the interference band.

[0040] An interference-free frequency band spectrum estimation module is used to acquire a normal intermediate frequency signal and, based on the normal intermediate frequency signal, obtain a reference spectrum for the interference-free frequency band.

[0041] The spectrum fusion module is used to fuse the reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band to obtain a complete reference spectrum;

[0042] The signal equalization module is used to perform equalization processing on the filtered intermediate frequency signal based on the complete reference spectrum to obtain the equalized GNSS signal.

[0043] Optionally, the interference band spectrum estimation module includes a GNSS signal prediction module and an anti-interference filter model module, wherein,

[0044] The GNSS signal prediction module is used to predict the intermediate frequency signal based on the tracking results of the receiver baseband output and the preset spectral amplitude, so as to obtain the predicted GNSS signal.

[0045] An anti-interference filter model module is used to input the predicted GNSS signal into the anti-interference filter, filter out the signals in the interference frequency band of the predicted GNSS signal, and obtain the filtered predicted signal.

[0046] A third aspect of the present invention provides a single-antenna anti-interference receiver, wherein the single-antenna receiver is provided with an anti-interference filter, and the anti-interference filter stores a frequency domain equalization program for a GNSS anti-interference filter. When the frequency domain equalization program for the GNSS anti-interference filter is executed by a processor, it implements any of the steps of the frequency domain equalization method for the GNSS anti-interference filter described above.

[0047] A fourth aspect of the present invention provides a computer-readable storage medium storing a frequency domain equalization program for a GNSS anti-interference filter, wherein when the frequency domain equalization program for the GNSS anti-interference filter is executed by a processor, the program implements any of the steps of the frequency domain equalization method for the GNSS anti-interference filter described above.

[0048] Compared with existing technologies, the beneficial effects of this solution are as follows:

[0049] This invention uses the intermediate frequency (IF) signal acquired by the receiver front-end as the processing object. It establishes reference spectra for the interference-free frequency band and the interference frequency band, respectively. The complete reference spectrum obtained by fusing these two spectra is used as a reference model for the equalizer to compensate for signal distortion. This model is then used to equalize the distorted IF signal after processing by the anti-interference filter, resulting in an equalized GNSS signal. Therefore, the method of this invention only requires equalization of the filtered IF signal based on the complete reference spectrum throughout the entire frequency domain equalization process, and it can obtain the complete reference spectrum without changing the internal structure of the traditional anti-interference filter. This not only significantly improves the signal distortion caused by traditional anti-interference filters, thereby effectively improving the anti-interference performance of GNSS and thus improving the quality of the receiver output signal, but also has the advantages of simple implementation, low computational load, and low hardware cost. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a schematic diagram of the frequency domain equalization system structure of the GNSS anti-interference filter of the present invention;

[0052] Figure 2 This is a flowchart of the frequency domain equalization method for the GNSS anti-interference filter of the present invention;

[0053] Figure 3 This is a comparison diagram of the spectrum of the interference signal before and after the anti-interference filtering of the present invention with the spectrum of the normal intermediate frequency signal. Detailed Implementation

[0054] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0055] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0056] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0057] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0058] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0061] For single-antenna receivers, anti-interference filters are currently one of the most effective means of mitigating the effects of interference. However, anti-interference filters simultaneously filter out interference signals and useful GNSS signals (usually referring to the normal GNSS signals mentioned below) from the intermediate frequency (IF) signal, leading to signal distortion and affecting signal quality. Traditional equalization techniques are difficult to use to compensate for this type of signal loss caused by interference filters. Therefore, this invention proposes a frequency domain equalization method for GNSS anti-interference filters. This method combines the spectral characteristics of the normal IF signal (usually referring to the normal signal mentioned below, where the normal signal refers to the mixed signal of normal GNSS signal and noise received by the receiver) with the receiver's tracking results to predict the GNSS signal, obtaining the predicted GNSS signal. The spectral characteristics of the normal signal and the predicted GNSS signal are then fused to obtain a complete reference spectrum. After filtering out the interference band signals from the IF signal of the GNSS signal, a filtered frequency domain signal is obtained. Then, based on the complete reference spectrum, the filtered frequency domain signal is equalized to obtain the equalized GNSS signal. The proposed frequency domain equalization technique for signal prediction assistance in GNSS anti-interference filters optimizes the GNSS anti-interference filter through independent modules and simple and feasible frequency domain compensation. It can effectively reduce GNSS signal distortion and significantly improve the anti-interference capability of GNSS, which has engineering application significance.

[0062] Exemplary methods

[0063] This invention provides a frequency domain equalization method for a GNSS anti-interference filter, which is deployed on a frequency domain equalization system for a GNSS anti-interference filter. However, it is not limited to this method and can also be used on other electronic devices such as mobile phones, smart wearable products, navigators, and drones that can receive GNSS signals. This method is designed to address the situation of signal distortion caused by anti-interference filters in single-antenna GNSS receivers in the frequency domain.

[0064] The structure of the frequency domain equalization system of the GNSS anti-interference filter in this embodiment is as follows: Figure 1As shown, it mainly includes: receiver front-end, anti-interference filter module, main Discrete Fourier Transform (DFT) module, signal equalization module, main inverse Discrete Fourier Transform (IDFT) module, receiver baseband module, and reference spectrum estimation module. Among them, the signal equalization module has two inputs and one output, the receiver baseband module has one input and two outputs, the GNSS signal prediction module has two inputs and two outputs, the anti-interference filter model module has one input and one output, and the secondary DFT module has three inputs and one output. Specifically, the signal received by the receiver is processed by the receiver front-end to obtain an intermediate frequency (IF) signal. The IF signal data is input to the anti-interference filter module. The input of the interference filter is connected to the input of the main DFT module. The output of the main DFT module is connected to the first input of the signal equalization module. The output of the signal equalization module is connected to the input of the main IDFT module. The output of the IDFT module is connected to the input of the receiver baseband module. The first output of the receiver baseband module is used for navigation calculation, and the second output is connected to the first input of the GNSS signal prediction module. Simultaneously, the preset signal amplitude is input to the GNSS signal prediction module through the second input. The first output of the GNSS signal prediction module is connected to the first input of the secondary DFT module, and the second output is connected to the input of the anti-interference filter model module. The output of the anti-interference filter model is connected to the second input of the secondary DFT module. The normal, interference-free signal is connected to the input of the receiver front-end model module. The output of the receiver front-end model module is connected to the third input of the secondary DFT module. The output of the secondary DFT module is connected to the input of the spectrum fusion module, and the output of the spectrum fusion module is connected to the second input of the signal equalization module.

[0065] The receiver front end is used to obtain the intermediate frequency signal based on the acquired GNSS signal;

[0066] The anti-interference filter module is used to input the intermediate frequency signal into the anti-interference filter, filter out the signals in the interference frequency band of the intermediate frequency signal, and obtain the filtered intermediate frequency signal;

[0067] The GNSS signal prediction module is used to predict the intermediate frequency signal based on the tracking results of the receiver baseband output and the preset spectral amplitude, so as to obtain the predicted GNSS signal.

[0068] The anti-interference filter model module is used to input the predicted GNSS signal into the anti-interference filter, filter out the signals in the interference frequency band of the predicted GNSS signal, and obtain the filtered predicted signal.

[0069] The interference-free frequency band spectrum estimation module is used to acquire the normal intermediate frequency signal and obtain the reference spectrum of the interference-free frequency band based on the normal intermediate frequency signal.

[0070] The interference band spectrum estimation module is used to obtain the reference spectrum of the interference band based on the predicted GNSS signal and the filtered predicted signal.

[0071] The spectrum fusion module is used to fuse the reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band to obtain a complete reference spectrum;

[0072] The signal equalization module is used to equalize the filtered intermediate frequency signal based on the complete reference spectrum to obtain the equalized GNSS signal.

[0073] The main DFT module is used to perform Fourier transform after inputting the intermediate frequency signal into the anti-interference filter and filtering out the signals in the interference band of the intermediate frequency signal, to obtain the filtered intermediate frequency signal.

[0074] The secondary DFT module is used to perform Fourier transform on the time-domain signal of the normal intermediate frequency signal to obtain the reference spectrum of the interference-free frequency band; it is also used to perform Fourier transform on the time-domain signals of the predicted GNSS signal and the filtered predicted signal respectively to obtain the reference spectrum of the interference frequency band.

[0075] The main IDFT module is used to perform equalization processing on the filtered intermediate frequency signal based on the complete reference spectrum, and then perform inverse Fourier transform on the obtained equalized frequency domain signal to obtain the equalized GNSS signal.

[0076] The GNSS receiver baseband module includes two modules: acquisition and tracking. The output of the acquisition module serves the tracking module, and the output of the tracking module is the final observation used for positioning calculation, namely pseudorange and carrier phase.

[0077] In this embodiment, the reference spectrum estimation module includes four modules: interference-free band spectrum estimation module, interference band spectrum estimation module, secondary DFT module, and spectrum fusion module. The interference-free band spectrum estimation module includes a normal signal output module and a receiver front-end model module. The interference band spectrum estimation module includes a GNSS signal prediction module and an anti-interference filter model module.

[0078] Furthermore, the reference spectrum estimation module includes an interference band spectrum estimation module and an interference-free band spectrum estimation module. The interference band spectrum estimation module is used to obtain the filtered frequency domain signal based on the predicted GNSS frequency domain signal and the filtered frequency domain signal, and to obtain the reference spectrum of the interference band based on the filtered frequency domain signal. The interference-free band spectrum estimation module is used to obtain the spectrum of the normal signal, and to obtain the reference spectrum of the interference-free band based on the spectrum of the normal signal. The reference spectrum estimation module is used to fuse the reference spectrum of the interference band and the reference spectrum of the interference-free band to obtain a complete reference spectrum.

[0079] Furthermore, the intermediate frequency signal acquired by the receiver front end is filtered out by the anti-interference filter module, and then Fourier transform is performed by the main DFT module to obtain the frequency domain signal of the filtered GNSS signal.

[0080] Furthermore, the reference spectrum estimation module calculates the complete reference spectrum required for equalization based on the tracking results. The signal equalization module compensates for the Fourier transform result of the input signal based on the complete reference spectrum. The compensated result is converted into a time-domain signal by the inverse Fourier transform of the main IDFT module. The time-domain signal is processed by the acquisition module and tracking module of the receiver baseband to obtain the tracking result, and the tracking result is fed back to the reference spectrum estimation module.

[0081] The system in this embodiment only needs to use the anti-interference filter module to obtain the filtered intermediate frequency signal, the receiver baseband tracking result, and the preset spectral amplitude. It can obtain a complete reference spectrum without changing the traditional anti-interference filter structure and the internal structure of the receiver signal processing. Then, the obtained complete reference spectrum is used to perform equalization processing on the filtered frequency domain signal, which can significantly improve the signal distortion caused by the traditional anti-interference filter, effectively improve the anti-interference performance of GNSS, and has the advantages of low complexity, low computational load, and low hardware cost. It is easy to implement and has practical engineering significance.

[0082] The frequency domain equalization system of the aforementioned GNSS anti-jamming filter is used to implement the frequency domain equalization method of the GNSS anti-jamming filter. The flowchart of this method is as follows: Figure 2 As shown, the main steps include:

[0083] Step S100: Obtain the intermediate frequency signal based on the acquired GNSS signal;

[0084] Specifically, the receiver front end converts the acquired interference signal into intermediate frequency data.

[0085] Step S200: Input the intermediate frequency signal into the anti-interference filter to filter out the signals in the interference frequency band of the intermediate frequency signal and obtain the filtered intermediate frequency signal;

[0086] Specifically, the anti-interference filter module analyzes the intermediate frequency (IF) signal, determines the frequency band of the interfering signal, adjusts the filter configuration, and filters out signal components within the interfering frequency band to obtain the filtered IF signal. It's easy to understand that the signal acquired by the receiver is usually a time-domain signal; in this embodiment, frequency domain equalization is performed by converting the time-domain signal to a frequency-domain signal using a Fourier transform. Common anti-interference filters include adaptive notch filters and frequency-domain adaptive filters.

[0087] Step S300: Based on the tracking results of the receiver baseband output and the preset spectral amplitude, predict and filter the intermediate frequency signal to obtain the reference spectrum of the interference band.

[0088] Specifically, initially there is no tracking result, and the GNSS prediction value is preset to empty. As time progresses, the GNSS signal prediction module estimates the GNSS signal at the next moment based on the tracking result output by the receiver baseband and the preset amplitude, obtains the predicted GNSS frequency domain signal, and inputs the predicted GNSS frequency domain signal into the anti-interference filter model module to obtain the filtered prediction signal. Then, the predicted GNSS signal and the filtered prediction signal are compared to obtain the spectrum of the filtered GNSS signal in the predicted GNSS signal, and use it as the reference spectrum of the interference band.

[0089] Step S400: Obtain the normal intermediate frequency signal, and based on the normal intermediate frequency signal, obtain the reference spectrum of the interference-free frequency band;

[0090] Specifically, the intermediate frequency (IF) signal in a normal GNSS signal is obtained, and based on the normal IF signal, its spectrum is obtained, and the spectrum of the normal IF signal is used as the reference spectrum for the interference-free frequency band.

[0091] Step S500: Fuse the reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band to obtain a complete reference spectrum;

[0092] Specifically, the spectrum fusion module superimposes the reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band to obtain a complete reference spectrum.

[0093] Step S600: Based on the complete reference spectrum, perform equalization processing on the filtered intermediate frequency signal to obtain the equalized GNSS signal.

[0094] Specifically, the signal equalization module compares the spectrum of the filtered intermediate frequency signal with the complete reference spectrum, performs equalization processing on the filtered intermediate frequency signal, and obtains the equalized frequency domain result; the IDFT module performs inverse Fourier transform on the equalized frequency domain result, converts it into a time domain signal, and inputs it to the receiver baseband module; the receiver baseband module processes the time domain signal to obtain the equalized GNSS signal; the tracking result is used for positioning calculation and input to the GNSS prediction module, repeating steps S300 to S700 to update the complete reference spectrum.

[0095] As can be seen, this embodiment uses the intermediate frequency (IF) signal acquired by the receiver front-end as the processing object, establishes reference spectra for the interference-free frequency band and interference frequency band respectively, and merges them as a reference model for the equalizer to compensate for signal distortion. It then performs equalization processing on the distorted IF signal after the anti-interference filter, obtaining the equalized GNSS signal. The entire frequency domain equalization process of this method only requires inputting the acquired GNSS IF signal into the anti-interference filter to obtain the filtered IF signal, and performing equalization processing on the filtered IF signal based on the complete reference spectrum. Moreover, it obtains the complete reference spectrum without changing the internal structure of the traditional anti-interference filter. This not only significantly improves the signal distortion caused by traditional anti-interference filters, thereby effectively improving the anti-interference performance of GNSS and thus improving the quality of the receiver output signal, but also has the advantages of simple implementation, low computational load, and low hardware cost.

[0096] In one embodiment, step S200, which involves inputting the intermediate frequency (IF) signal to an anti-interference filter to filter out signals in the interference frequency band of the IF signal, and obtaining a filtered IF signal, specifically includes:

[0097] Step S210: Analyze the characteristics of the intermediate frequency signal using an anti-interference filter to determine the frequency band of the interference signal and obtain the interference frequency band;

[0098] Step S220: Based on the interference frequency band, adjust the notch frequency of the anti-interference filter, and filter out the signal in the interference frequency band based on the notch frequency to obtain the filtered time domain signal.

[0099] Alternatively, by comparing the spectral amplitude of the intermediate frequency signal with a preset threshold value, signals within the interference frequency band can be suppressed to obtain the filtered time-domain signal;

[0100] Step S230: Perform a Fourier transform on the filtered time-domain signal to obtain the filtered intermediate frequency signal.

[0101] This embodiment uses two common anti-interference filters, namely the adaptive notch filter or the frequency domain adaptive filter, as examples for detailed explanation.

[0102] The first type is an adaptive notch filter, which can automatically track and filter out interference signals. Its transfer function is:

[0103]

[0104] Where z is the Z-transform operator, r∈(0,1) determines the bandwidth of the adaptive notch filter, which is usually set between 0.95 and 0.99, and the notch frequency f stop By sampling frequency f s Determined by the parameter α, denoted as f stop =f s arccos(α) / 2π[Hz].

[0105] Since the power of the interference signal is much greater than that of the GNSS signal and noise, the adaptive notch filter filters out the interference signal by ensuring that the energy of the output signal y is minimized and adaptively adjusting the notch frequency to the interference frequency.

[0106] min(J)=min(E[y 2 (2)

[0107] Another type is the frequency-domain adaptive filter, which suppresses interference signals by comparing the signal's spectral amplitude with a preset threshold. When the signal's spectral amplitude exceeds the preset threshold, the frequency-domain filter sets the amplitude at that frequency to 0, thus removing the interference signal. The transfer function of the frequency-domain adaptive filter is:

[0108]

[0109] Where k is the k-th frequency point of the short-time Fourier transform, and its corresponding frequency is f. k =kf s / N, N is the number of Fourier transform points, f s R is the sampling frequency. k | is the signal at f k Spectral amplitude at V T,k This is the corresponding threshold.

[0110] Since the spectral amplitude of a normal signal follows a Rayleigh distribution, while the spectral amplitude of a signal under interference conditions far exceeds the normal range, the threshold value V... T,k The false alarm probability P can be preset. fa Noise power σ under normal conditions 2 The settings are as follows:

[0111]

[0112] The filtered time-domain signal is obtained based on an adaptive notch filter or a frequency-domain adaptive filter. Since this invention uses frequency-domain equalization technology, the filtered time-domain signal is subjected to Fourier transform to convert it into a filtered intermediate frequency signal in the frequency domain.

[0113] In this embodiment, since the processing of the filtered intermediate frequency signal is not affected by the type, number, or parameters of the anti-interference filter, various types of GNSS anti-interference filters can be selected for filtering optimization, making it widely applicable.

[0114] In one implementation, based on the tracking result of the receiver baseband output and a preset spectral amplitude in step S300, the intermediate frequency signal is predicted and filtered to obtain a reference spectrum for the interference band, specifically including:

[0115] Step S310: Based on the tracking results of the receiver baseband output and the preset spectral amplitude, predict the intermediate frequency signal to obtain the predicted GNSS signal;

[0116] Specifically, at the initial moment there is no tracking result, and the GNSS prediction value is preset to empty. As time goes by, the GNSS signal prediction module estimates the GNSS signal at the next moment based on the tracking result output by the receiver baseband and the preset amplitude. After time-frequency domain conversion, the predicted GNSS frequency domain signal is obtained, and the predicted GNSS frequency domain signal is input to the anti-interference filter model module and the sub-DFT module respectively.

[0117] Step S320: Input the predicted GNSS signal into the anti-interference filter to filter out the signals in the interference frequency band of the predicted GNSS signal and obtain the filtered predicted signal;

[0118] Specifically, the anti-interference filter model module is configured the same as the anti-interference filter, processes the GNSS prediction values ​​to obtain the filtered GNSS signal, and inputs it to the secondary DFT module.

[0119] Step S330: Based on the predicted GNSS signal and the filtered predicted signal, obtain the reference spectrum of the interference band;

[0120] Specifically, by comparing the predicted GNSS signal with the filtered predicted signal, the spectrum of the filtered GNSS signal in the predicted GNSS signal is obtained and used as the reference spectrum for the interference band.

[0121] In one implementation, the intermediate frequency signal is predicted based on the tracking result of the receiver baseband output and the preset spectral amplitude in step 310 to obtain the predicted GNSS signal, specifically including:

[0122] Step 311: Obtain the code delay and code tracking error of the previous moment, and obtain the predicted code delay based on the code delay and code tracking error;

[0123] Step 312: Obtain the Doppler frequency offset and carrier frequency tracking error of the previous moment, and obtain the predicted Doppler frequency offset based on the Doppler frequency offset and carrier frequency tracking error;

[0124] Step 313: Obtain the phase and carrier phase tracking error of the previous moment, and obtain the predicted phase based on the phase and carrier phase tracking error;

[0125] Step 314: Based on the tracking results of the receiver baseband output at the previous moment, obtain the predicted navigation message;

[0126] Step 315: Based on the predicted code delay, predicted Doppler frequency offset, predicted phase, predicted navigation message, and preset spectral amplitude, predict the intermediate frequency signal to obtain the predicted GNSS signal.

[0127] For example, in the interference band, the reference spectrum is designed based on the frequency domain results of the predicted GNSS signal. In static or low-dynamic environments, the Doppler frequency shift of the received signal is very small over a short period, and the code offset and carrier frequency for the next moment can be estimated based on the receiver's baseband intermediate frequency signal and carrier tracking error. Furthermore, since the navigation message period is relatively long (typically 20ms), the symbols in the navigation message can be approximated as being the same as the previous moment. Therefore, the predicted value of the GNSS signal at time t is:

[0128]

[0129] Among them, A p The preset signal amplitude is generally set to the initial signal amplitude under interference-free conditions; c represents the C / A code of the tracking satellite; f IF τ is a fixed value representing the intermediate frequency (IF) of the GNSS receiver; p The predicted code delay is the code delay from the previous moment plus the code tracking error. The predicted Doppler frequency offset is the Doppler frequency offset from the previous moment plus the carrier frequency tracking error from the previous moment; θ p The predicted phase is the phase from the previous time step plus the carrier phase tracking error from the previous time step; d p The predicted navigation message is represented by the sign of the correlation value in the tracking result of the previous moment; that is, if the correlation value is positive, then d... p Then it is 1, otherwise, d p It is -1.

[0130] The predicted GNSS signal is processed by an anti-interference filter to obtain the filtered GNSS signal, i.e., the filtered predicted signal. Fourier transforms are then performed on both the predicted and filtered GNSS signals to obtain the spectral results of the GNSS prediction. Spectral results of filtered GNSS predictions Right now

[0131]

[0132]

[0133] This embodiment comprehensively considers the changing characteristics of GNSS signals within the interference frequency band. By utilizing the code delay, Doppler frequency offset, carrier phase tracking error, and navigation message format of the previous moment, it accurately infers the predicted value of the GNSS signal at the current moment from multiple perspectives, making the prediction results closer to reality and more accurate.

[0134] The GNSS signal prediction method proposed in this embodiment can predict signals from various satellite navigation systems such as GPS, BeiDou, GLONASS, and Galileo. It has wide applicability and high engineering application value.

[0135] In one implementation, obtaining the reference spectrum of the interference band based on the predicted GNSS signal and the filtered predicted signal in step S330 specifically includes:

[0136] Step S331: Calculate the spectrum of the predicted GNSS signal and the spectrum of the filtered predicted signal;

[0137] Step S332: Based on the difference between the spectrum of the predicted GNSS signal and the spectrum of the filtered predicted signal, obtain the reference spectrum of the interference band.

[0138] Combining formulas (6) and (7), the frequency domain result of the filtered GNSS signal can be approximated as follows: This spectrum is then used as a reference spectrum for equalizing the interference band signal. It's easy to understand that, to avoid the interference band affecting the accuracy of the predicted GNSS signal, it's necessary to first determine the reference spectrum for the interference band. In this embodiment, the reference spectrum for the interference band is obtained by subtracting the spectrum of the predicted GNSS signal in the interference environment from the spectrum of the filtered predicted signal obtained after removing the interference spectrum. This method is simple and efficient.

[0139] In one implementation, obtaining the normal intermediate frequency signal in step S400, and obtaining a reference spectrum for the interference-free frequency band based on the normal intermediate frequency signal, specifically includes:

[0140] Step S410: Acquire several sets of normal intermediate frequency signals and perform Fourier transform to obtain the spectrum of several sets of normal signals;

[0141] Step S420: Calculate the average value of the spectrum of all normal signals to obtain the reference spectrum of the interference-free frequency band.

[0142] For example, in a normal, interference-free environment, GNSS signals are often overwhelmed by noise signals, and the power of these noise signals is generally stable. Therefore, the spectrum of the normal intermediate frequency (IF) signal processed by the receiver is determined by the antenna and the filters and amplifiers in the receiver front-end. Based on this fact, the amplitude of the reference spectrum in the interference-free band can be obtained from the spectral characteristics of the normal signal. That is, multiple sets of IF signals from normal signals are collected, and short-time Fourier transforms are performed to obtain the spectra of M sets of normal signals. The average amplitude of these spectra is used as a reference model to correct the amplitude of the interference-free band signal. This interference-free band reference spectrum |R ref,k | can be represented as:

[0143]

[0144] in, Let N be the nth data point in the Mth group, N be the number of Fourier transform points, and k be the kth frequency point in the short-time Fourier transform. Indicates the received intermediate frequency signal Perform a short-time Fourier transform.

[0145] In one implementation, the reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band in step S700 are fused to obtain a complete reference spectrum, specifically including:

[0146] The reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band are superimposed to obtain the complete reference spectrum.

[0147] For example, in the interference-free frequency band, the signal amplitude is reduced, so the reference spectrum is the amplitude of the normal signal, providing a reference for signal equalization; in the interference frequency band, the signal is severely attenuated, and the filtered GNSS signal is used as the reference spectrum for equalizing the distorted signal. Therefore, combining formulas (6), (7), and (8), the complete reference spectrum R... ref,k , is represented as:

[0148]

[0149] Among them, F J This is an interference frequency band.

[0150] This embodiment combines the characteristics of the signal spectrum in the interference-free and interference frequency bands, solves the spectrum in the interference-free and interference frequency bands respectively, and then merges the two into a complete reference spectrum to ensure that the final reference spectrum can effectively reflect the spectrum characteristics under various real-world environments, laying a good foundation for improving the accuracy of subsequent frequency domain equalization processing.

[0151] In one implementation, the filtered intermediate frequency signal, based on the complete reference spectrum, is subjected to equalization processing in step S600 to obtain an equalized GNSS signal, specifically including:

[0152] Step S610: In the interference-free frequency band, obtain the amplitude of the filtered intermediate frequency signal, the amplitude of the complete reference spectrum, and the preset initial value of the amplitude gain coefficient. Adjust the value of the amplitude gain coefficient to minimize the absolute value of the difference between the amplitude of the filtered intermediate frequency signal and the amplitude of the complete reference spectrum, and obtain the equalized frequency domain signal in the interference-free frequency band.

[0153] Step S620: Within the interference frequency band, compensate the reference spectrum of the filtered interference frequency band to the amplitude of the filtered intermediate frequency signal to obtain the equalized frequency domain signal in the interference frequency band.

[0154] Step S630: Based on the equalized frequency domain signal in the interference-free frequency band and the equalized frequency domain signal in the interference frequency band, obtain the equalized frequency domain signal;

[0155] Step S640: Perform an inverse Fourier transform on the equalized frequency domain signal to obtain the equalized GNSS signal.

[0156] Figure 3 The figure shows simulation diagrams of the spectrum of the interference signal before and after anti-interference filtering, and the spectrum of the normal signal. As can be seen from the figure, when an interference signal is present, because the interference power is much greater than the normal signal, the spectral amplitude of the interference band is much higher than the normal value. To ensure the energy stability of the output signal, the front-end automatic gain controller reduces the amplifier coefficient, resulting in the signal spectrum value of the interference-free band being lower than the normal value. When the interfered signal is processed by the anti-interference filter, the signal in the interference band is significantly attenuated, leading to significant distortion of the filtered signal. Therefore, the equalization process needs to compensate for the amplitude attenuation caused by the automatic gain controller in the interference-free band and the signal attenuation caused by the anti-interference filter at the interference frequency. The complete reference spectrum design is divided into two parts: the interference-free band spectrum and the interference band spectrum.

[0157] Based on the above analysis, signal equalization involves comparing the frequency domain results of the acquired GNSS signal with the reference spectrum of formula (9). The equalization algorithm eqz is as follows:

[0158]

[0159] in, For the frequency domain results of the collected interference-free GNSS signals, S k This is the frequency domain result of the GNSS signal in the interference band collected before filtering. The frequency domain result of the GNSS signal after anti-interference filtering, G k This is the amplitude gain coefficient.

[0160] The main purpose of signal equalization algorithms is to adjust the gain in interference-free frequency bands. This ensures that the amplitude of the interference-free frequency band signal approximates the reference spectrum amplitude: in the interference band, the filtered GNSS prediction value is similar to the filtered actual GNSS signal, and the frequency domain result of the filtered GNSS signal is obtained. Compensation is applied to the interference frequency band. The equalization results from both the interference-free and interference frequency bands are combined to obtain the overall frequency domain result of the equalized signal. It can be represented as:

[0161]

[0162] in, Signal before equalization The phase.

[0163] Then, the main IDFT module performs an inverse Fourier transform on the frequency domain result of the overall equalized signal, converts it into a time domain signal, and inputs it into the receiver baseband module.

[0164] Equalized signal Performing an inverse Fourier transform (IDFT) yields the equalized time-domain signal, i.e., the equalized GNSS signal. It can be represented as:

[0165]

[0166] Furthermore, the equalized signal is input to the receiver baseband module to obtain the tracking result of the original acquired GNSS signal. The tracking result is used for positioning calculation on the one hand, and input to the GNSS prediction module on the other hand. Steps S300 to S700 are repeated to update the complete reference spectrum.

[0167] This embodiment employs a reference spectrum-assisted signal equalization algorithm, combining equalization strategies for both the interference band and the interference-free band for separate equalization processing. The equalization results from the interference band and the interference-free band are then fused to obtain an overall equalization effect. This effectively improves the signal distortion problem caused by traditional anti-interference filters, thereby significantly enhancing the anti-interference performance of the GNSS receiver and improving the quality of the GNSS signal.

[0168] The frequency domain equalization system corresponding to the frequency domain equalization method of this invention is embedded in the anti-interference filter and can be used as an independent structure. It only requires obtaining the filtered intermediate frequency signal and the receiver baseband tracking result through the frequency domain equalization system, without changing the traditional anti-interference filter structure or the internal structure of the receiver signal processing. This makes it easy to implement and reduces hardware costs. Furthermore, the entire operation only requires simple short-time Fourier transform and inverse transform for data processing, using multipliers for GNSS signal prediction and adders and amplifiers for signal equalization. This results in low computational load, low complexity, and ease of implementation, offering broad application prospects and commercial value.

[0169] Corresponding to the frequency domain equalization method of the GNSS anti-interference filter described above, this embodiment of the invention also provides a single-antenna anti-interference receiver. The single-antenna anti-interference receiver is equipped with an anti-interference filter, and the anti-interference filter stores a frequency domain equalization program for the GNSS anti-interference filter. When the frequency domain equalization program of the GNSS anti-interference filter is executed by the processor, the steps of the frequency domain equalization method of the GNSS anti-interference filter described above are implemented, which will not be repeated here.

[0170] This invention also provides a computer-readable storage medium storing a frequency domain equalization program for a GNSS anti-interference filter. When the frequency domain equalization program for the GNSS anti-interference filter is executed by a processor, it implements the steps of any frequency domain equalization method for a GNSS anti-interference filter provided in this invention.

[0171] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0172] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the above device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this invention. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0173] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0174] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0175] In the embodiments provided by this invention, it should be understood that the disclosed apparatus / terminal devices and methods can be implemented in other ways. For example, the apparatus / terminal device embodiments described above are merely illustrative. For instance, the division of the above modules or units is merely a logical functional division, and in actual implementation, it can be divided in other ways. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0176] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not mean that the essence of the corresponding technical solutions deviates from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A frequency domain equalization method for GNSS anti-interference filters, characterized in that, Includes the following steps: Based on the acquired GNSS signals, the intermediate frequency signal is obtained; The intermediate frequency signal is input to an anti-interference filter to filter out signals in the interference frequency band of the intermediate frequency signal, thereby obtaining a filtered intermediate frequency signal; Based on the tracking results of the receiver baseband output and the preset spectral amplitude, the intermediate frequency signal is predicted and filtered to obtain the reference spectrum of the interference band. Obtain a normal intermediate frequency signal, and based on the normal intermediate frequency signal, obtain a reference spectrum of the interference-free frequency band; The reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band are fused to obtain a complete reference spectrum; Based on the complete reference spectrum, the filtered intermediate frequency signal is subjected to equalization processing to obtain the equalized GNSS signal; The method of predicting and filtering the intermediate frequency signal based on the tracking result of the receiver baseband output and the preset spectral amplitude to obtain a reference spectrum for the interference band includes: Based on the tracking results of the receiver baseband output and the preset spectral amplitude, the intermediate frequency signal is predicted to obtain the predicted GNSS signal; The predicted GNSS signal is input into the anti-interference filter to filter out signals in the interference frequency band of the predicted GNSS signal, thereby obtaining the filtered predicted signal. Based on the predicted GNSS signal and the filtered predicted signal, a reference spectrum for the interference band is obtained; The method of predicting the intermediate frequency signal based on the tracking result of the receiver baseband output and the preset spectral amplitude to obtain the predicted GNSS signal includes: Obtain the code delay and code tracking error of the previous moment, and obtain the predicted code delay based on the code delay and the code tracking error; Obtain the Doppler frequency offset and carrier frequency tracking error of the previous moment, and obtain the predicted Doppler frequency offset based on the Doppler frequency offset and the carrier frequency tracking error; Obtain the phase and carrier phase tracking error of the previous moment, and obtain the predicted phase based on the phase and carrier phase tracking error; Based on the tracking result of the receiver baseband output at the previous moment, the predicted navigation message is obtained; The intermediate frequency signal is predicted based on the predicted code delay, the predicted Doppler frequency offset, the predicted phase, the predicted navigation message, and the preset spectral amplitude to obtain the predicted GNSS signal.

2. The frequency domain equalization method for the GNSS anti-interference filter according to claim 1, characterized in that, The step of inputting the intermediate frequency signal to an anti-interference filter to filter out signals in the interference frequency band of the intermediate frequency signal and obtain a filtered intermediate frequency signal includes: The characteristics of the intermediate frequency signal are analyzed using the anti-interference filter to determine the frequency band of the interference signal and obtain the interference frequency band. Based on the interference frequency band, the notch frequency of the anti-interference filter is adjusted, and the signal in the interference frequency band is filtered out based on the notch frequency to obtain the filtered time-domain signal. Alternatively, by comparing the spectral amplitude of the intermediate frequency signal with a preset threshold value, the signal in the interference frequency band can be suppressed to obtain the filtered time-domain signal; The filtered time-domain signal is subjected to Fourier transform to obtain the filtered intermediate frequency signal.

3. The frequency domain equalization method for the GNSS anti-interference filter according to claim 1, characterized in that, The process of obtaining a reference spectrum for the interference band based on the predicted GNSS signal and the filtered predicted signal includes: Calculate the spectrum of the predicted GNSS signal and the spectrum of the filtered predicted signal; The reference spectrum of the interference band is obtained based on the difference between the spectrum of the predicted GNSS signal and the spectrum of the filtered predicted signal.

4. The frequency domain equalization method for the GNSS anti-interference filter according to claim 1, characterized in that, The process of equalizing the filtered intermediate frequency signal based on the complete reference spectrum to obtain an equalized GNSS signal includes: Within the interference-free frequency band, the amplitude of the filtered intermediate frequency signal, the amplitude of the complete reference spectrum, and the initial value of the preset amplitude gain coefficient are obtained. The value of the amplitude gain coefficient is adjusted so that the absolute value of the difference between the amplitude of the filtered intermediate frequency signal and the amplitude of the complete reference spectrum is minimized, thereby obtaining the equalized frequency domain signal in the interference-free frequency band. Within the interference frequency band, the reference spectrum of the filtered interference frequency band is compensated to the amplitude of the filtered intermediate frequency signal to obtain the equalized frequency domain signal in the interference frequency band. Based on the equalized frequency domain signal in the interference-free frequency band and the equalized frequency domain signal in the interference frequency band, the equalized frequency domain signal is obtained. The equalized frequency domain signal is subjected to inverse Fourier transform to obtain the equalized GNSS signal.

5. A frequency domain equalization system for a GNSS anti-interference filter, characterized in that, The system includes: The receiver front end is used to obtain the intermediate frequency signal based on the acquired GNSS signal; An anti-interference filter module is used to input the intermediate frequency signal into an anti-interference filter, filter out signals in the interference frequency band of the intermediate frequency signal, and obtain a filtered intermediate frequency signal. The interference band spectrum estimation module is used to predict and filter the intermediate frequency signal based on the tracking results of the receiver baseband output and the preset spectrum amplitude to obtain the reference spectrum of the interference band. An interference-free frequency band spectrum estimation module is used to acquire a normal intermediate frequency signal and, based on the normal intermediate frequency signal, obtain a reference spectrum for the interference-free frequency band. The spectrum fusion module is used to fuse the reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band to obtain a complete reference spectrum; The signal equalization module is used to perform equalization processing on the filtered intermediate frequency signal based on the complete reference spectrum to obtain the equalized GNSS signal; The method of predicting and filtering the intermediate frequency signal based on the tracking result of the receiver baseband output and the preset spectral amplitude to obtain a reference spectrum for the interference band includes: Based on the tracking results of the receiver baseband output and the preset spectral amplitude, the intermediate frequency signal is predicted to obtain the predicted GNSS signal; The predicted GNSS signal is input into the anti-interference filter to filter out signals in the interference frequency band of the predicted GNSS signal, thereby obtaining the filtered predicted signal. Based on the predicted GNSS signal and the filtered predicted signal, a reference spectrum for the interference band is obtained; The method of predicting the intermediate frequency signal based on the tracking result of the receiver baseband output and the preset spectral amplitude to obtain the predicted GNSS signal includes: Obtain the code delay and code tracking error of the previous moment, and obtain the predicted code delay based on the code delay and the code tracking error; Obtain the Doppler frequency offset and carrier frequency tracking error of the previous moment, and obtain the predicted Doppler frequency offset based on the Doppler frequency offset and the carrier frequency tracking error; Obtain the phase and carrier phase tracking error of the previous moment, and obtain the predicted phase based on the phase and carrier phase tracking error; Based on the tracking result of the receiver baseband output at the previous moment, the predicted navigation message is obtained; The intermediate frequency signal is predicted based on the predicted code delay, the predicted Doppler frequency offset, the predicted phase, the predicted navigation message, and the preset spectral amplitude to obtain the predicted GNSS signal.

6. The frequency domain equalization system for the GNSS anti-interference filter according to claim 5, characterized in that, The interference band spectrum estimation module includes a GNSS signal prediction module and an anti-interference filter model module. The GNSS signal prediction module is used to predict the intermediate frequency signal based on the tracking result of the receiver baseband output and the preset spectrum amplitude to obtain the predicted GNSS signal. An anti-interference filter model module is used to input the predicted GNSS signal into the anti-interference filter, filter out the signals in the interference frequency band of the predicted GNSS signal, and obtain the filtered predicted signal.

7. A single-antenna anti-interference receiver, characterized in that, The single-antenna anti-interference receiver is equipped with an anti-interference filter, and the anti-interference filter stores a frequency domain equalization program for the GNSS anti-interference filter. When the frequency domain equalization program for the GNSS anti-interference filter is executed by the processor, it implements the steps of the frequency domain equalization method for the GNSS anti-interference filter as described in any one of claims 1-4.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a frequency domain equalization program for a GNSS anti-jamming filter. When the frequency domain equalization program for the GNSS anti-jamming filter is executed by a processor, it implements the steps of the frequency domain equalization method for the GNSS anti-jamming filter as described in any one of claims 1-4.

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