Frequency domain equalization method and system of GNSS (Global Navigation Satellite System) anti-interference filter, receiver and medium

Abstract

The invention provides a frequency domain equalization method and system of a GNSS (Global Navigation Satellite System) anti-interference filter, a receiver and a medium, and particularly relates to the technical field of GNSS interference signal suppression, and the scheme comprises the following steps: inputting an intermediate frequency signal of a collected GNSS signal into the anti-interference filter to obtain a filtered intermediate frequency signal; predicting and filtering the intermediate frequency signal based on a tracking result output by a receiver baseband and a preset frequency spectrum amplitude to obtain a reference frequency spectrum of an interference frequency band; obtaining a reference spectrum of an interference-free frequency band based on the normal intermediate frequency signal; and fusing the reference frequency spectrum of the non-interference frequency band and the reference frequency spectrum of the interference frequency band to obtain a complete reference frequency spectrum, and further carrying out equalization processing on the filtered intermediate frequency signal to obtain an equalized GNSS signal. According to the scheme, signal distortion caused by a traditional anti-interference filter can be remarkably improved, so that the anti-interference performance of the GNSS is effectively improved, and the quality of signals output by a receiver is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of GNSS interference signal suppression, and in particular to a frequency domain equalization method, system, receiver and medium of a GNSS anti-interference filter. Background Art

[0002] At present, the Global Navigation Satellite System (GNSS) plays an important supporting role in the rapid development of global Internet of Things and artificial intelligence technologies, and is widely used in smart phones, smart watches, navigation devices, and drones. However, since the GNSS system itself has a relatively weak anti-interference ability, it is particularly important to ensure the reliability of the GNSS system in an interference environment.

[0003] In the prior art, GNSS interference signal filtering technology is usually used for interference suppression, which mainly adopts appropriate filtering technology to reduce interference signals based on the analysis results of data collected by the GNSS front end, such as adaptive notch technology, frequency domain adaptive filtering technology and transform domain filtering technology. Although these interference filtering technologies can effectively suppress the impact of interference signals on GNSS, useful GNSS signals in the interference frequency band are also filtered out at the same time. Therefore, GNSS anti-interference filtering technology has the problem of easily causing useful GNSS signal distortion or loss, thereby causing the quality of GNSS signals to decline and reducing the performance of GNSS.

[0004] Based on this, equalization technology is usually used in communication systems to alleviate the signal distortion problem caused by channel propagation. Common equalization algorithms include linear equalization, decision feedback equalization, adaptive equalization and blind equalization. These equalization technologies correct the waveform, amplitude or phase of the signal through corresponding filtering or compensation technology to match the corresponding characteristics of the reference model, where the reference model is usually established based on the original transmission signal model and channel characteristics. In actual environments, the received GNSS signal is usually unknown, resulting in the inability to obtain the reference signal required for equalization. Therefore, traditional equalization technology is difficult to use to compensate for the distortion caused by GNSS interference, resulting in the signal distortion caused by traditional anti-interference filters cannot be effectively improved, and the anti-interference performance of GNSS cannot be effectively improved. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a frequency domain equalization method, system, receiver and medium for a GNSS anti-interference filter, aiming to solve the problem in the prior art that the signal distortion caused by the traditional anti-interference filter cannot be effectively improved and the anti-interference performance of the GNSS cannot be effectively improved.

[0006] In order to achieve the above object, 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 collected GNSS signal, an intermediate frequency signal is obtained;

[0008] Inputting the intermediate frequency signal into an anti-interference filter to filter out the signal in the interference frequency band of the intermediate frequency signal to obtain a filtered intermediate frequency signal;

[0009] Based on the tracking result outputted by the baseband of the receiver and the preset spectrum amplitude, the intermediate frequency signal is predicted and filtered to obtain a reference spectrum of the interference frequency band;

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

[0011] Merging the reference spectrum of the non-interference frequency band with the reference spectrum of the interference frequency band to obtain a complete reference spectrum;

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

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

[0014] Based on the tracking result output by the receiver baseband and the preset spectrum amplitude, the intermediate frequency signal is predicted to obtain a predicted GNSS signal;

[0015] Inputting the predicted GNSS signal into the anti-interference filter, filtering out the signal in the interference frequency band of the predicted GNSS signal, and obtaining a filtered predicted signal;

[0016] Based on the predicted GNSS signal and the filtered predicted signal, obtaining a reference spectrum of an interference frequency band;

[0017] Optionally, inputting the intermediate frequency signal into an anti-interference filter, filtering out signals in an interference frequency band in the intermediate frequency signal, and obtaining a filtered intermediate frequency signal includes:

[0018] Analyzing the characteristics of the intermediate frequency signal using the anti-interference filter, determining the frequency band of the interference signal, and obtaining the interference frequency band;

[0019] Based on the interference frequency band, adjusting the notch frequency of the anti-interference filter, and filtering out the signal in the interference frequency band based on the notch frequency to obtain a filtered time domain signal;

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

[0021] The filtered time domain signal is subjected to Fourier transformation to obtain a filtered intermediate frequency signal.

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

[0023] Acquire a code delay and a code tracking error at a previous moment, and obtain a predicted code delay based on the code delay and the code tracking error;

[0024] Acquire a Doppler frequency deviation and a carrier frequency tracking error at a previous moment, and obtain a predicted Doppler frequency deviation based on the Doppler frequency deviation and the carrier frequency tracking error;

[0025] Acquire the phase and carrier phase tracking error at a previous moment, and obtain a predicted phase based on the phase and the carrier phase tracking error;

[0026] Obtaining a predicted navigation message based on the tracking result outputted by the receiver baseband at a previous moment;

[0027] The intermediate frequency signal is predicted according to the predicted code delay, the predicted Doppler frequency deviation, the predicted phase, the predicted navigation message and the preset spectrum amplitude to obtain a predicted GNSS signal.

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

[0029] Calculating a frequency spectrum of the predicted GNSS signal and a frequency spectrum of the filtered predicted signal;

[0030] Based on the difference between the spectrum of the predicted GNSS signal and the spectrum of the filtered predicted signal, a reference spectrum of the interference frequency band is obtained.

[0031] Optionally, performing equalization processing on the filtered intermediate frequency signal based on the complete reference spectrum to obtain an equalized GNSS signal includes:

[0032] In the interference-free frequency band, 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 are obtained, and the value of the amplitude gain coefficient is adjusted 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, so as to obtain the frequency domain signal after equalization in the interference-free frequency band;

[0033] In 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 a frequency domain signal after equalization on the interference frequency band;

[0034] Obtaining an equalized frequency domain signal based on the frequency domain signal equalized on the interference-free frequency band and the frequency domain signal equalized on the interference frequency band;

[0035] Performing an inverse Fourier transform on the equalized frequency domain signal to obtain an 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 an intermediate frequency signal based on the collected GNSS signal;

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

[0039] An interference frequency band spectrum estimation module is used to predict and filter the intermediate frequency signal based on the tracking result output by the baseband receiver and a preset spectrum amplitude to obtain a reference spectrum of the interference frequency band;

[0040] The non-interference frequency band spectrum estimation module is used to obtain a normal intermediate frequency signal, and obtain a reference spectrum of the non-interference frequency band based on the normal intermediate frequency signal;

[0041] A spectrum fusion module, used for fusing the reference spectrum of the non-interference frequency band with 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 an equalized GNSS signal.

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

[0044] A GNSS signal prediction module, used to predict the intermediate frequency signal based on the tracking result output by the receiver baseband and a preset spectrum amplitude, so as to obtain a predicted GNSS signal;

[0045] The anti-interference filter model module is used to input the predicted GNSS signal into the anti-interference filter, filter out the signal within the interference frequency band in 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, which is provided with an anti-interference filter. A frequency domain equalization program of a GNSS anti-interference filter is stored on the anti-interference filter. When the frequency domain equalization program of the GNSS anti-interference filter is executed by a processor, the steps of any one of the above-mentioned frequency domain equalization methods of the GNSS anti-interference filter are implemented.

[0047] A fourth aspect of the present invention provides a computer-readable storage medium, on which a frequency domain equalization program for a GNSS anti-interference filter is stored. When the frequency domain equalization program for the GNSS anti-interference filter is executed by a processor, the steps of any one of the above-mentioned frequency domain equalization methods for the GNSS anti-interference filter are implemented.

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

[0049] The present invention takes the intermediate frequency signal collected by the front end of the receiver as the processing object, establishes the reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band respectively, and uses the complete reference spectrum obtained after the fusion of the two as the reference model for the equalizer to compensate for the signal distortion, and performs equalization processing on the distorted intermediate frequency signal after the anti-interference filter processing to obtain the equalized GNSS signal. It can be seen that in the whole frequency domain equalization processing process, the method of the present invention only needs to perform equalization processing on the filtered intermediate frequency signal based on the complete reference spectrum, and the complete reference spectrum can be obtained without changing the internal structure of the traditional anti-interference filter. It can not only significantly improve the signal distortion caused by the traditional anti-interference filter, thereby effectively improving the anti-interference performance of GNSS, and then improve the quality of the signal output by the receiver, but also has the advantages of simple implementation, small calculation amount, and low hardware cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

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

[0052] Figure 2 It is a flow chart of the frequency domain equalization method of the GNSS anti-interference filter of the present invention;

[0053] Figure 3 It is a comparison diagram of the interference signal spectrum and the normal intermediate frequency signal spectrum before and after the anti-interference filtering of the present invention. DETAILED DESCRIPTION

[0054] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

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

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

[0057] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

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

[0059] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present 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 to mitigate the effects of interference. However, anti-interference filters will simultaneously filter out interference signals and useful GNSS signals (usually referring to the normal GNSS signals mentioned below) in the intermediate frequency signal, resulting in signal distortion problems and affecting signal quality. However, traditional equalization techniques are difficult to use to compensate for this type of signal loss caused by interference filters. Therefore, the present invention proposes a frequency domain equalization method for GNSS anti-interference filters suitable for GNSS anti-interference filters. The method combines the spectrum characteristics of a normal intermediate frequency signal (usually referring to the normal signal mentioned below, where the normal signal refers to a mixed signal of a normal GNSS signal and noise received by the receiver), and uses the tracking results of the receiver to predict the GNSS signal, obtain the predicted GNSS signal, and fuse the spectrum characteristics of the normal signal and the spectrum characteristics of the predicted GNSS signal to obtain a complete reference spectrum; the filtered frequency domain signal is obtained by filtering out the signal in the interference frequency band in the intermediate frequency signal of the GNSS signal, and then the filtered frequency domain signal is equalized based on the complete reference spectrum to obtain an equalized GNSS signal. The signal prediction-assisted frequency domain equalization technology suitable for GNSS anti-interference filters proposed in this method can optimize the GNSS anti-interference filters through independent modules and simple and feasible frequency domain compensation, which can effectively reduce GNSS signal distortion and significantly improve the anti-interference capability of GNSS, and has engineering application significance.

[0062] Exemplary Methods

[0063] An embodiment of the present invention provides a frequency domain equalization method for a GNSS anti-interference filter, which is deployed on a frequency domain equalization system of the GNSS anti-interference filter, but is not limited thereto. It can also be other electronic devices such as mobile phones, smart wearable products, navigators, drones, etc. that can receive GNSS signals. It is aimed at compensating for the signal distortion caused by the anti-interference filter of a single-antenna GNSS receiver in the frequency domain.

[0064] The structure of the frequency domain equalization system of the GNSS anti-interference filter of this embodiment is as follows: Figure 1As shown, it mainly includes: a receiver front end, an anti-interference filter module, a main discrete Fourier transform (Discrete Fourier Transform, DFT) module, that is, a main DFT module, a signal equalization module, a main inverse discrete Fourier transform (Inverse Discrete Fourier Transform, IDFT) module, that is, a main IDFT module, a receiver baseband module and a reference spectrum estimation module, wherein the signal equalization module has two input terminals and one output terminal, the receiver baseband module has one input terminal and two output terminals, the GNSS signal prediction module has two input terminals and two output terminals, the anti-interference filter model module has one input terminal and one output terminal, and the secondary DFT module has three input terminals and one output terminal. Specifically, the signal received by the receiver is processed by the receiver front end to obtain an intermediate frequency signal, and the intermediate frequency signal data is input into the anti-interference filter module, the input end of the interference filter is connected to the input end of the main DFT module, the output end of the main DFT module is connected to the first input end of the signal equalization module, the output end of the signal equalization module is connected to the input end of the main IDFT module, the output end of the IDFT module is connected to the input end of the receiver baseband module, the first output end of the receiver baseband module is used for navigation solution, and the second output end is connected to the first input end of the GNSS signal prediction module; at the same time, the preset signal amplitude is input into the GNSS signal prediction module through the second input end of the GNSS signal prediction module, the first output end of the GNSS signal prediction module is connected to the first input end of the secondary DFT module, the second output end is connected to the input end of the anti-interference filter model module, and the output end of the anti-interference filter model is connected to the second input end of the secondary DFT module; the normal interference-free signal is connected to the input end of the receiver front-end model module, the output end of the receiver front-end model module is connected to the third input end of the secondary DFT module, the output end of the secondary DFT module is connected to the input end of the spectrum fusion module, and the output end of the spectrum fusion module is connected to the second input end of the signal equalization module.

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

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

[0067] A GNSS signal prediction module is used to predict the intermediate frequency signal based on the tracking result output by the receiver baseband and the preset spectrum amplitude to obtain the predicted GNSS signal;

[0068] An anti-interference filter model module is used to input the predicted GNSS signal into the anti-interference filter, filter out the signal in the interference frequency band in the predicted GNSS signal, and obtain a filtered predicted signal;

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

[0070] An interference frequency band spectrum estimation module, used for obtaining a reference spectrum of the interference frequency band based on the predicted GNSS signal and the filtered predicted signal;

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

[0072] A signal equalization module is used to perform equalization processing on the filtered intermediate frequency signal based on the complete reference spectrum to obtain an equalized GNSS signal;

[0073] The main DFT module is used to input the intermediate frequency signal into the anti-interference filter and filter out the signal in the interference frequency band of the intermediate frequency signal, and then perform Fourier transform 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 a 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 to obtain a reference spectrum of the interference frequency band;

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

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

[0077] In this embodiment, the reference spectrum estimation module includes four modules: an interference-free frequency band spectrum estimation module, an interference frequency band spectrum estimation module, a secondary DFT module and a spectrum fusion module. The interference-free frequency band spectrum estimation module includes a normal signal output module and a receiver front-end model module. The interference frequency 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 frequency band spectrum estimation module and a non-interference frequency band spectrum estimation module, wherein the interference frequency band spectrum estimation module is used to obtain a filtered frequency domain signal based on the predicted GNSS frequency domain signal and the filtered frequency domain signal, and obtain a reference spectrum of the interference frequency band based on the filtered frequency domain signal; the non-interference frequency band spectrum estimation module is used to obtain the spectrum of the normal signal, and obtain the reference spectrum of the non-interference frequency band based on the spectrum of the normal signal; the reference spectrum estimation module is used to fuse the reference spectrum of the interference frequency band and the reference spectrum of the non-interference frequency band to obtain a complete reference spectrum.

[0079] Furthermore, the intermediate frequency signal collected by the front end of the receiver is filtered out by the anti-interference filter module, and is Fourier transformed 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, and the signal equalization module compensates 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 an inverse Fourier transform by the main IDFT module. The time domain signal is processed by the capture 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 of 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 spectrum amplitude. It does not need to change the traditional anti-interference filter structure and the internal structure of the receiver signal processing to obtain a complete reference spectrum. 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 and effectively improve the anti-interference performance of GNSS. It also has the advantages of low complexity, small calculation amount, and low hardware cost, is easy to implement, and has engineering practice significance.

[0082] The frequency domain equalization system of the GNSS anti-interference filter is used to implement the frequency domain equalization method of the GNSS anti-interference filter. The flowchart of the method is as follows: Figure 2 As shown, it mainly includes the following steps:

[0083] Step S100: obtaining an intermediate frequency signal based on the collected GNSS signal;

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

[0085] Step S200: inputting the intermediate frequency signal into an anti-interference filter, filtering out the signal in the interference frequency band of the intermediate frequency signal, and obtaining a filtered intermediate frequency signal;

[0086] Specifically, the anti-interference filter module analyzes the intermediate frequency signal, determines the frequency band of the interference signal, adjusts the configuration of the filter, filters out the signal components in the interference frequency band, and obtains the filtered intermediate frequency signal. It is easy to understand that the signal obtained by the receiver is usually a time domain signal. The premise of frequency domain equalization in this embodiment is to convert the time domain signal into a frequency domain signal through Fourier transform. Common anti-interference filters include adaptive notch filters and frequency domain adaptive filters.

[0087] Step S300: Based on the tracking result output by the baseband receiver and the preset spectrum amplitude, the intermediate frequency signal is predicted and filtered to obtain a reference spectrum of the interference frequency band;

[0088] Specifically, there is no tracking result at the initial moment, 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 and the preset amplitude output by the receiver baseband, obtains the predicted GNSS frequency domain signal, and inputs the predicted GNSS frequency domain signal into the anti-interference filter model module respectively to obtain the filtered prediction signal; then, the predicted GNSS signal and the filtered prediction signal are compared to obtain the spectrum of the GNSS signal filtered out in the predicted GNSS signal, and use it as the reference spectrum of the interference frequency band.

[0089] Step S400: acquiring a normal intermediate frequency signal, and obtaining a reference spectrum of a non-interference frequency band based on the normal intermediate frequency signal;

[0090] Specifically, an intermediate frequency signal in a normal GNSS signal is obtained, and based on the normal intermediate frequency signal, a spectrum of the normal intermediate frequency signal is obtained, and the spectrum of the normal intermediate frequency signal is used as a reference spectrum of a non-interference frequency band.

[0091] Step S500: fusing the reference spectrum of the non-interference 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 non-interference 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, equalize the filtered intermediate frequency signal to obtain an 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 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 solution on the one hand, and is input into the GNSS prediction module on the other hand. Steps S300 to S700 are repeated to update the complete reference spectrum.

[0095] It can be seen that this embodiment takes the intermediate frequency signal collected by the front end of the receiver as the processing object, establishes the reference spectrum of the interference-free frequency band and the reference spectrum of the interference frequency band respectively, and fuses the two as the reference model for the equalizer to compensate for signal distortion, and performs equalization processing on the distorted intermediate frequency signal after processing by the anti-interference filter to obtain the equalized GNSS signal. The entire frequency domain equalization processing process of this method only requires inputting the intermediate frequency signal of the collected GNSS signal into the anti-interference filter to obtain the filtered intermediate frequency signal, and performing equalization processing on the filtered intermediate frequency signal based on the complete reference spectrum, and the complete reference spectrum can be obtained without changing the internal structure of the traditional anti-interference filter. It can not only significantly improve the signal distortion caused by the traditional anti-interference filter, thereby effectively improving the anti-interference performance of GNSS, and then improve the quality of the signal output by the receiver, but also has the advantages of simple implementation, small calculation amount, and low hardware cost.

[0096] In one implementation, in step S200, inputting the intermediate frequency signal into the anti-interference filter, filtering out the signal in the interference frequency band of the intermediate frequency signal, and obtaining the filtered intermediate frequency signal specifically includes:

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

[0098] Step S220: adjusting the notch frequency of the anti-interference filter based on the interference frequency band, and filtering out the signal in the interference frequency band based on the notch frequency to obtain a filtered time domain signal;

[0099] Alternatively, by comparing the spectrum amplitude of the intermediate frequency signal with a preset threshold value, the signal in the interference frequency band is suppressed to obtain a filtered time domain signal;

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

[0101] This embodiment is described in detail by taking an adaptive notch filter or a frequency domain adaptive filter, two common anti-interference filters, as examples.

[0102] The first is an adaptive notch filter, which can track and filter out interference signals by itself. 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 and parameter α, denoted as f stop =f s arccos(α) / 2π[Hz].

[0105] Since the power of the interference signal is much greater than the GNSS signal and noise, the adaptive notch filter ensures that the output signal y has the minimum energy and adaptively adjusts the notch frequency to the interference frequency, thereby filtering out the interference signal. The cost function of the adaptive notch filter is:

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

[0107] The other is a frequency domain adaptive filter, which suppresses interference signals by comparing the signal spectrum amplitude with a preset threshold. When the signal spectrum amplitude exceeds the preset threshold, the frequency domain filter sets the frequency amplitude to 0 to remove the interference signal. The transfer function of the frequency domain adaptive filter is:

[0108]

[0109] Among them, k is the kth 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 is the sampling frequency. |R k | is the signal at f k The spectrum amplitude at V T,k is the corresponding threshold.

[0110] Since the spectrum amplitude of the normal signal follows the Rayleigh distribution, and the spectrum amplitude of the signal in the interference environment is far beyond the normal range, the threshold value V T,k The false alarm probability P can be preset fa and the normal noise power σ 2 Settings, specifically:

[0111]

[0112] The filtered time domain signal is obtained based on an adaptive notch filter or a frequency domain adaptive filter. Since the present invention uses frequency domain equalization technology, the filtered time domain signal is Fourier transformed and converted into a filtered intermediate frequency signal in the frequency domain.

[0113] In this embodiment, since the type, number and parameters of the anti-interference filter are not affected during the processing of the filtered intermediate frequency signal, various types of GNSS anti-interference filters can be selected for filtering optimization, which has a wide range of applications.

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

[0115] Step S310: predicting the intermediate frequency signal based on the tracking result output by the receiver baseband and the preset spectrum amplitude to obtain a predicted GNSS signal;

[0116] Specifically, there is no tracking result at the initial moment, 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 and preset amplitude output by the receiver baseband, and obtains the predicted GNSS frequency domain signal after time-frequency domain conversion. The predicted GNSS frequency domain signal is then input into the anti-interference filter model module and the secondary DFT module respectively.

[0117] Step S320: inputting the predicted GNSS signal into an anti-interference filter, filtering out the signal in the interference frequency band in the predicted GNSS signal, and obtaining a filtered predicted signal;

[0118] Specifically, the anti-interference filter model module has the same configuration as the anti-interference filter, processes the GNSS prediction value to obtain the filtered GNSS signal, and inputs it into the secondary DFT module.

[0119] Step S330: obtaining a reference spectrum of the interference frequency band based on the predicted GNSS signal and the filtered predicted signal;

[0120] Specifically, the predicted GNSS signal is compared with the filtered predicted signal, and the spectrum of the GNSS signal filtered out of the predicted GNSS signal is obtained, and the spectrum is used as a reference spectrum of the interference frequency band.

[0121] In one embodiment, predicting the intermediate frequency signal based on the tracking result output by the receiver baseband and the preset spectrum amplitude in step 310 to obtain the predicted GNSS signal specifically includes:

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

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

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

[0125] Step 314: obtaining a predicted navigation message based on the tracking result outputted by the receiver baseband at the previous moment;

[0126] Step 315: predict the intermediate frequency signal according to the predicted code delay, the predicted Doppler frequency deviation, the predicted phase, the predicted navigation message and the preset spectrum amplitude to obtain the predicted GNSS signal.

[0127] For example, in the interference frequency band, the reference spectrum is designed based on the frequency domain results of the predicted GNSS signal. In a static or low dynamic environment, the Doppler shift change of the received signal in a short time is very small, and the code offset and carrier frequency at the next moment can be estimated based on the receiver baseband intermediate frequency signal and carrier tracking error. In addition, since the navigation message period is relatively long (generally 20ms), the symbol of the navigation message can be approximated to be the same as the previous moment. Then, the predicted value of the GNSS signal at time t is:

[0128]

[0129] Among them, A p is the preset signal amplitude, which is generally set to the amplitude of the initial signal when there is no interference; c represents the C / A code of the tracking satellite; f IF is a fixed value, which represents the intermediate frequency of the GNSS receiver; τ p is the predicted code delay, which is the code delay at the previous moment plus the code tracking error; is the predicted Doppler frequency deviation, which is the Doppler frequency deviation at the previous moment plus the carrier frequency tracking error at the previous moment; θ p is the predicted phase, which is the phase at the previous moment plus the carrier phase tracking error at the previous moment; d p is the predicted navigation message, is the sign of the correlation value in the tracking result at the previous moment, that is, if the correlation value is positive, d p If d p is -1.

[0130] The predicted GNSS signal is processed by the anti-interference filter to obtain the filtered GNSS signal, that is, the filtered predicted signal. The predicted GNSS signal and the filtered GNSS signal are Fourier transformed to obtain the spectrum result of the GNSS predicted value. Spectral results of the filtered GNSS predictions Right now

[0131]

[0132]

[0133] This embodiment comprehensively considers the changing characteristics of the GNSS signal in the interference frequency band, and uses the code delay, Doppler frequency deviation, carrier phase tracking error and navigation message format of the previous moment to accurately infer the predicted value of the GNSS signal at the current moment from multiple angles, so that the prediction result is closer to reality and the prediction result is more accurate.

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

[0135] In one implementation, obtaining a reference spectrum of the interference frequency 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: obtaining a reference spectrum of the interference frequency band based on the difference between the spectrum of the predicted GNSS signal and the spectrum of the filtered predicted signal.

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

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

[0140] Step S410: collecting several groups of normal intermediate frequency signals, and performing Fourier transform to obtain frequency spectra of several groups of normal signals;

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

[0142] For example, in a normal environment without interference, the GNSS signal is drowned by the noise signal, and the power of the noise signal is generally relatively stable. Therefore, the spectrum of the normal intermediate frequency signal processed by the receiver is determined by the filter and amplifier in the antenna and the front end of the receiver. Based on this fact, the amplitude of the reference spectrum of the interference-free frequency band can be obtained from the spectrum characteristics of the normal signal. That is, the intermediate frequency signals of multiple groups of normal signals are collected, and the spectrum of M groups of normal signals is obtained by short-time Fourier transform. The average value of the spectrum amplitude is used as a reference model for correcting the amplitude of the interference-free frequency band signal. The interference-free frequency band reference spectrum|R ref,k | can be expressed as:

[0143]

[0144] in, is the nth data point of the Mth group, N is the number of Fourier transform points, k is the kth frequency point of 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 non-interference frequency band and the reference spectrum of the interference frequency band are merged in step S700 to obtain a complete reference spectrum, which specifically includes:

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

[0147] For example, in the interference-free frequency band, the signal amplitude is reduced, so the reference spectrum is the spectrum 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 to equalize the distorted signal. Therefore, combining formula (6), formula (7) and formula (8), the complete reference spectrum R ref,k , expressed as:

[0148]

[0149] Among them, F J Interference frequency band.

[0150] This embodiment combines the characteristics of the signal spectrum in the non-interference frequency band and the interference frequency band, solves the spectrum in the non-interference frequency band and the interference frequency band 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 environments, laying a good foundation for subsequently improving the accuracy of frequency domain equalization processing.

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

[0152] Step S610: in the interference-free frequency band, 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 are obtained, and the value of the amplitude gain coefficient is adjusted 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, so as to obtain the frequency domain signal after equalization in the interference-free frequency band;

[0153] Step S620: in the interference frequency band, compensating the reference spectrum of the filtered interference frequency band to the amplitude of the filtered intermediate frequency signal to obtain a frequency domain signal after equalization on the interference frequency band;

[0154] Step S630: obtaining an equalized frequency domain signal based on the frequency domain signal equalized on the non-interference frequency band and the frequency domain signal equalized on the interference frequency band;

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

[0156] Figure 3 As shown in the figure, it is a spectrum simulation diagram of the interference signal before and after the anti-interference filtering and the spectrum of the normal signal. It can be seen from the figure that when there is an interference signal, since the interference power is much greater than the normal signal, the spectrum amplitude of the interference frequency band is much higher than the normal value. In order to ensure the energy stability of the output signal, the front-end automatic gain controller will reduce the amplifier coefficient, resulting in the signal spectrum value of the non-interference frequency band being lower than the normal value. When the interfered signal is processed by the anti-interference filter, the signal in the interference frequency band is significantly attenuated, resulting in obvious distortion of the filtered signal. Therefore, the equalization processing needs to compensate for the amplitude attenuation caused by the automatic gain controller in the non-interference frequency band and the signal attenuation caused by the anti-interference filter at the interference frequency, and the design of the complete reference spectrum is divided into two parts: the non-interference frequency band spectrum and the interference frequency band spectrum.

[0157] Based on the above analysis, signal equalization is to compare the frequency domain results of the collected GNSS signal with the reference spectrum of formula (9). The equalization algorithm eqz is:

[0158]

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

[0160] The main purpose of the signal equalization algorithm is to adjust the gain in the interference-free frequency band Make the amplitude of the interference-free frequency band signal similar to the reference spectrum amplitude: In the interference frequency band, the filtered GNSS prediction value is similar to the actual GNSS signal after filtering, and the frequency domain result of the filtered GNSS signal Compensate to the interference frequency band, combine the equalization results of the non-interference frequency band and the interference frequency band, and the frequency domain result of the overall equalized signal It can be expressed as:

[0161]

[0162] in, The signal before equalization 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 Perform an inverse Fourier transform (IDFT) to obtain the equalized time domain signal, that is, the equalized GNSS signal It can be expressed as:

[0165]

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

[0167] This embodiment adopts a reference spectrum-assisted signal equalization algorithm, combines the equalization strategies of the interference frequency band and the non-interference frequency band to perform equalization processing respectively, and merges the equalization results in the interference frequency band and the non-interference frequency band to obtain an overall equalization processing effect, which can effectively improve the signal distortion problem caused by the traditional anti-interference filter, thereby effectively improving the anti-interference performance of the GNSS receiver and significantly improving the quality of the GNSS signal.

[0168] The frequency domain equalization system corresponding to the frequency domain equalization method of the present invention is embedded in the anti-interference filter and can be used as an independent structure. It only needs to obtain 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 and the internal structure of the receiver processing signal. It is easy to implement and has low hardware cost. Moreover, in the entire operation process, it only needs to perform data processing through simple short-time Fourier transform and inverse transform, use a multiplier to realize GNSS signal prediction, and use an adder and an amplifier to realize signal equalization. It has a small amount of calculation, low complexity, and is easy to implement. It has broad application prospects and commercial value.

[0169] Corresponding to the frequency domain equalization method of the above-mentioned GNSS anti-interference filter, an embodiment of the present invention further provides a single-antenna anti-interference receiver, on which an anti-interference filter is provided, and a frequency domain equalization program of the GNSS anti-interference filter is stored on the anti-interference filter. When the frequency domain equalization program of the GNSS anti-interference filter is executed by the processor, the steps of implementing the frequency domain equalization method of the above-mentioned GNSS anti-interference filter are not repeated here.

[0170] An embodiment of the present invention also provides a computer-readable storage medium, on which a frequency domain equalization program for a GNSS anti-interference filter is stored. When the frequency domain equalization program for a GNSS anti-interference filter is executed by a processor, the steps of any one of the frequency domain equalization methods for a GNSS anti-interference filter provided in an embodiment of the present invention are implemented.

[0171] It should be understood that the serial numbers of the steps in the above embodiments do not imply a sequence of execution, and the execution sequence 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 can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the above-mentioned 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 embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0173] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0174] Those skilled in the art will appreciate that the units and algorithm steps of each example 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0175] In the embodiments provided by the present invention, it should be understood that the disclosed apparatus / terminal equipment and method can be implemented in other ways. For example, the apparatus / terminal equipment embodiments described above are only illustrative, for example, the division of the above modules or units is only a logical function division, and in actual implementation, other division methods can be used, 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 embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it should be understood by those skilled in the art that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features therein may be replaced by equivalents. However, these modifications or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A frequency domain equalization method for a GNSS anti-interference filter, characterized in that: The following steps are involved: Based on the collected GNSS signal, an intermediate frequency signal is obtained; Inputting the intermediate frequency signal into an anti-interference filter to filter out the signal in the interference frequency band of the intermediate frequency signal to obtain a filtered intermediate frequency signal; Based on the tracking result outputted by the baseband of the receiver and the preset spectrum amplitude, the intermediate frequency signal is predicted and filtered to obtain a reference spectrum of the interference frequency band; Acquire a normal intermediate frequency signal, and obtain a reference spectrum of a non-interference frequency band based on the normal intermediate frequency signal; Merging the reference spectrum of the non-interference frequency band with the reference spectrum of the interference frequency band to obtain a complete reference spectrum; Based on the complete reference spectrum, the filtered intermediate frequency signal is equalized to obtain an equalized GNSS signal.

2. The frequency domain equalization method of the GNSS anti-interference filter according to claim 1, characterized in that: The method predicts and filters the intermediate frequency signal based on the tracking result output by the baseband receiver and the preset spectrum amplitude to obtain a reference spectrum of the interference frequency band, including: Based on the tracking result output by the receiver baseband and the preset spectrum amplitude, the intermediate frequency signal is predicted to obtain a predicted GNSS signal; Inputting the predicted GNSS signal into the anti-interference filter, filtering out the signal in the interference frequency band of the predicted GNSS signal, and obtaining a filtered predicted signal; Based on the predicted GNSS signal and the filtered predicted signal, a reference frequency spectrum of an interference frequency band is obtained.

3. The frequency domain equalization method of the GNSS anti-interference filter according to claim 1, characterized in that: The step of inputting the intermediate frequency signal into an anti-interference filter, filtering out the signal in the interference frequency band of the intermediate frequency signal, and obtaining the filtered intermediate frequency signal comprises: Analyzing the characteristics of the intermediate frequency signal using the anti-interference filter, determining the frequency band of the interference signal, and obtaining the interference frequency band; Based on the interference frequency band, adjusting the notch frequency of the anti-interference filter, and filtering out the signal in the interference frequency band based on the notch frequency to obtain a filtered time domain signal; Alternatively, by comparing the spectrum amplitude of the intermediate frequency signal with a preset threshold value, the signal in the interference frequency band is suppressed to obtain a filtered time domain signal; The filtered time domain signal is subjected to Fourier transformation to obtain a filtered intermediate frequency signal.

4. The frequency domain equalization method of the GNSS anti-interference filter according to claim 2, characterized in that: The step of predicting the intermediate frequency signal based on the tracking result output by the receiver baseband and the preset spectrum amplitude to obtain the predicted GNSS signal includes: Acquire a code delay and a code tracking error at a previous moment, and obtain a predicted code delay based on the code delay and the code tracking error; Acquire a Doppler frequency deviation and a carrier frequency tracking error at a previous moment, and obtain a predicted Doppler frequency deviation based on the Doppler frequency deviation and the carrier frequency tracking error; Acquire the phase and carrier phase tracking error at a previous moment, and obtain a predicted phase based on the phase and the carrier phase tracking error; Obtaining a predicted navigation message based on the tracking result outputted by the receiver baseband at a previous moment; The intermediate frequency signal is predicted according to the predicted code delay, the predicted Doppler frequency deviation, the predicted phase, the predicted navigation message and the preset spectrum amplitude to obtain a predicted GNSS signal.

5. The frequency domain equalization method of the GNSS anti-interference filter according to claim 2, characterized in that: The obtaining, based on the predicted GNSS signal and the filtered predicted signal, a reference spectrum of the interference frequency band comprises: Calculating a frequency spectrum of the predicted GNSS signal and a frequency spectrum of the filtered predicted signal; Based on the difference between the spectrum of the predicted GNSS signal and the spectrum of the filtered predicted signal, a reference spectrum of the interference frequency band is obtained.

6. The frequency domain equalization method of the GNSS anti-interference filter according to claim 1, characterized in that: The step of performing equalization processing on the filtered intermediate frequency signal based on the complete reference spectrum to obtain an equalized GNSS signal includes: In the interference-free frequency band, 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 are obtained, and the value of the amplitude gain coefficient is adjusted 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, so as to obtain the frequency domain signal after equalization in the interference-free frequency band; In 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 a frequency domain signal after equalization on the interference frequency band; Obtaining an equalized frequency domain signal based on the frequency domain signal equalized on the interference-free frequency band and the frequency domain signal equalized on the interference frequency band; Performing an inverse Fourier transform on the equalized frequency domain signal to obtain an equalized GNSS signal.

7. A frequency domain equalization system for a GNSS anti-interference filter, characterized in that: The system comprises: The receiver front end is used to obtain an intermediate frequency signal based on the collected GNSS signal; An anti-interference filter module is used to input the intermediate frequency signal into the anti-interference filter, filter out the signal in the interference frequency band of the intermediate frequency signal, and obtain a filtered intermediate frequency signal; An interference frequency band spectrum estimation module is used to predict and filter the intermediate frequency signal based on the tracking result output by the baseband receiver and a preset spectrum amplitude to obtain a reference spectrum of the interference frequency band; The non-interference frequency band spectrum estimation module is used to obtain a normal intermediate frequency signal, and obtain a reference spectrum of the non-interference frequency band based on the normal intermediate frequency signal; A spectrum fusion module, used for fusing the reference spectrum of the non-interference frequency band with 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 an equalized GNSS signal.

8. The frequency domain equalization system of the GNSS anti-interference filter according to claim 1, characterized in that: The interference frequency band spectrum estimation module includes a GNSS signal prediction module and an anti-interference filter model module, wherein: A GNSS signal prediction module, used to predict the intermediate frequency signal based on the tracking result output by the receiver baseband and a preset spectrum amplitude, so as to obtain a predicted GNSS signal; The anti-interference filter model module is used to input the predicted GNSS signal into the anti-interference filter, filter out the signal within the interference frequency band in the predicted GNSS signal, and obtain the filtered predicted signal.

9. A single-antenna anti-interference receiver, characterized in that: The single antenna receiver is provided with an anti-interference filter, and the anti-interference filter stores a frequency domain equalization program of 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 as claimed in any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a frequency domain equalization program of a GNSS anti-interference filter, and when the frequency domain equalization program of the GNSS anti-interference filter is executed by a processor, the steps of the frequency domain equalization method of the GNSS anti-interference filter as claimed in any one of claims 1 to 6 are implemented.

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