Adaptive filtering method and system for GPS circuit, and storage medium

Abstract

The invention provides an adaptive filtering method and system for a GPS circuit and a storage medium, and the method comprises the steps: scanning a radio frequency signal of a GPS in real time through broadband radio frequency sampling, and carrying out the analysis based on an energy peak detection algorithm to obtain an interference energy distribution spectrum; determining interference energy based on a preset frequency point to match a preset interference library; if a known interference frequency point is matched, a preset fixed band elimination unit is activated, and if an unknown interference frequency point is matched, LC parameters are dynamically calculated, a programmable resonance unit is configured, and interference signals are dynamically suppressed; verifying the signal-to-noise ratio based on a preset period, calculating to obtain an optimization index, and if the optimization index is insufficient, triggering LC parameter iterative updating until positioning is stable; and a core technical guarantee is provided for a high-precision positioning scene.

Description

Technical Field

[0001] The present invention relates to the field of GPS circuits, and more particularly to an adaptive filtering method, system and storage medium for GPS circuits. Background Art

[0002] With the increasing prevalence of in-vehicle navigation, drones, and IoT devices, GPS positioning reliability faces severe challenges. Existing technologies generally employ static filtering solutions combining fixed LC circuits with SAW filters. These solutions suffer from rigid anti-interference capabilities, a lack of mechanisms to address unknown interference, poor environmental adaptability, and unbalanced energy efficiency. Traditional filtering circuits can only suppress interference at preset frequencies, such as signals with a primary frequency of 1575MHz, but are ineffective against newer interference signals such as the second harmonics of Band 13 (1496MHz) and Band 14 (1582MHz). In densely populated urban areas, such interference can significantly reduce the signal-to-noise ratio and cause frequent satellite loss. Static LC circuits are unable to respond to sudden interference, leading to positioning inaccuracies in areas such as airports and factories, requiring manual resets. Furthermore, fixed filtering parameters ignore the effects of temperature drift and component aging, resulting in band-stop frequency shifts. This increases the probability of filter failure, especially in high-speed mobile scenarios. Currently, efforts to improve anti-interference capabilities are being made by widening the stopband, but this introduces additional insertion loss, increases the gain of the signal amplifier, and significantly increases power consumption.

[0003] In summary, the essence of existing solutions is passive defense, while complex electromagnetic environments require a dynamic immune system. Therefore, an adaptive filtering technology for GPS circuits is urgently needed. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to provide an adaptive filtering method, system and storage medium for GPS circuits, which construct a collaborative mechanism of interference perception, dynamic suppression and closed-loop optimization; scan interference signals in real time through wide-band RF sampling, generate interference energy distribution spectrum based on energy peak detection algorithm, and accurately identify interference frequency points exceeding the threshold; activate preset fixed band-stop units for known interference, dynamically calculate LC parameters for unknown interference, configure programmable resonant units, and realize dynamic suppression of interference signals; verify the degree of signal-to-noise ratio optimization based on a preset period, and if the optimization index is insufficient, trigger iterative update of LC parameters until positioning is stable; provide core technical guarantee for high-precision positioning scenarios.

[0005] A first aspect of the present invention provides an adaptive filtering method for a GPS circuit, the method comprising: Acquire a first radio frequency signal received by a GPS antenna; Obtaining an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm; Obtain a first frequency point, and obtain an interference threshold corresponding to the first frequency point; Determining interference energy at a first frequency point according to the interference energy distribution spectrum; If the interference energy exceeds the interference threshold, it is marked as an interference frequency point; According to the interference frequency, matching a preset interference library; If it is the first interference frequency, the corresponding fixed band-stop unit is activated; If it is the second interference frequency point, dynamically calculating the LC parameters according to the interference frequency point for configuring the programmable resonant unit; Based on the preset iteration cycle, the optimization index is calculated according to the signal-to-noise ratio before and after filtering; If the optimization index is lower than a preset index threshold, the LC parameter update mechanism is triggered.

[0006] In this solution, the interference energy distribution spectrum is obtained according to the first radio frequency signal based on the preset energy peak detection algorithm, specifically including: In response to a preset first band-stop filter, obtaining a first interference signal according to the first radio frequency signal; Based on a preset frequency band window, the first interference signal is divided into sub-channels with the first frequency point as the center frequency; Calculating the root mean square value of the signal energy in each sub-channel according to the first interference signal to obtain interference energy; The interference energy distribution spectrum is composed according to the first frequency point and the interference energy.

[0007] In this solution, the preset interference library is matched according to the interference frequency, specifically: Obtaining a first characteristic frequency point and a second characteristic frequency point according to the interference library; Determining whether the interference frequency point is a first characteristic frequency point; If yes, determining that the interference frequency is the first interference frequency; If not, determining that the interference frequency is the second interference frequency; If the interference frequency point is the second characteristic frequency point, the characteristic LC parameter is output.

[0008] In this solution, if the first interference frequency is present, the corresponding fixed band-stop unit is activated, specifically: If the first interference frequency corresponds to a preset first harmonic interference, turning on the first series resonant circuit; If the first interference frequency corresponds to a preset second harmonic interference, activating the first parallel resonant network; Obtaining an auxiliary frequency band according to the first interference frequency point; According to the auxiliary frequency band, a corresponding notch filter is activated.

[0009] In this solution, the LC parameters are dynamically calculated based on the interference frequency point to configure the programmable resonant unit, specifically including: Obtaining a band-stop frequency range and a target suppression depth according to the interference frequency and the interference energy; According to the band-stop frequency range, a preset initial combination of LC values ​​is selected, and the LC values ​​are iteratively optimized based on the gradient descent method until the target suppression depth is met, thereby obtaining LC parameters; Writing the C parameter of the LC parameter into the register of the digitally controlled capacitor array; The switch coding of the inductor matrix is ​​set according to the L parameter of the LC parameter.

[0010] In this solution, the triggering LC parameter update mechanism specifically includes: Detect and obtain the unsuppressed residual interference frequency and its residual interference energy; Obtaining a frequency offset according to the residual interference frequency and the LC parameter; If the frequency offset exceeds a preset offset threshold, re-iteratively optimizing the LC value; If the residual interference energy exceeds a preset energy threshold, the number of capacitor array stages is increased.

[0011] A second aspect of the present invention provides an adaptive filtering system for a GPS circuit, including an adaptive filtering method program for a GPS circuit. When the adaptive filtering method program for a GPS circuit is executed by the processor, the following steps are implemented: Acquire a first radio frequency signal received by a GPS antenna; Obtaining an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm; Obtaining a first frequency point, and obtaining an interference threshold corresponding to the first frequency point; Determining interference energy at a first frequency point according to the interference energy distribution spectrum; If the interference energy exceeds the interference threshold, it is marked as an interference frequency point; According to the interference frequency, matching a preset interference library; If it is the first interference frequency, the corresponding fixed band-stop unit is activated; If it is the second interference frequency point, dynamically calculating the LC parameters according to the interference frequency point for configuring the programmable resonant unit; Based on the preset iteration cycle, the optimization index is calculated according to the signal-to-noise ratio before and after filtering; If the optimization index is lower than a preset index threshold, the LC parameter update mechanism is triggered.

[0012] In this solution, the interference energy distribution spectrum is obtained according to the first radio frequency signal based on the preset energy peak detection algorithm, specifically including: In response to a preset first band-stop filter, obtaining a first interference signal according to the first radio frequency signal; Based on a preset frequency band window, the first interference signal is divided into sub-channels with the first frequency point as the center frequency; Calculating the root mean square value of the signal energy in each sub-channel according to the first interference signal to obtain interference energy; The interference energy distribution spectrum is composed according to the first frequency point and the interference energy.

[0013] In this solution, the preset interference library is matched according to the interference frequency, specifically: Obtaining a first characteristic frequency point and a second characteristic frequency point according to the interference library; Determining whether the interference frequency point is a first characteristic frequency point; If yes, determining that the interference frequency is the first interference frequency; If not, determining that the interference frequency is the second interference frequency; If the interference frequency point is the second characteristic frequency point, the characteristic LC parameter is output.

[0014] A third aspect of the present invention provides a computer-readable storage medium, which includes an adaptive filtering method program for a GPS circuit. When the adaptive filtering method program for a GPS circuit is executed by a processor, the steps of the adaptive filtering method for a GPS circuit as described in any one of the above items are implemented.

[0015] The present invention provides an adaptive filtering method, system and storage medium for a GPS circuit. The method scans the GPS radio frequency signal in real time through wide-band radio frequency sampling, and obtains the interference energy distribution spectrum based on analysis of an energy peak detection algorithm. The method determines the interference energy based on a preset frequency point to match a preset interference library. If the matching frequency point is a known interference frequency point, the method activates a preset fixed band-stop unit. If the matching frequency point is an unknown interference frequency point, the method dynamically calculates LC parameters and configures a programmable resonant unit to achieve dynamic suppression of interference signals. The method verifies the signal-to-noise ratio based on a preset period and calculates an optimization index. If the optimization index is insufficient, the method triggers an iterative update of the LC parameters until the positioning is stable. The method provides core technical support for high-precision positioning scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope.

[0017] Figure 1 A flow chart of an adaptive filtering method for a GPS circuit according to the present invention is shown; Figure 2 A flowchart for constructing an interference energy distribution spectrum provided by an embodiment of the present invention is shown; Figure 3 A matching flow chart of an interference library provided by an embodiment of the present invention is shown; Figure 4 A block diagram of an adaptive filtering system for a GPS circuit according to the present invention is shown. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] Unless otherwise defined, all terms (including technical and scientific terms) used in the embodiments of the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined in this manner in the embodiments of the present invention.

[0020] The words "first", "second" and similar terms used in the embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "one", "an" or "the" do not indicate a quantity limitation, but rather indicate the existence of at least one. Similarly, words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The steps before or after the method of the embodiment of the present invention do not necessarily have to be performed in exact order. On the contrary, the various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0021] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0022] Figure 1 The flowchart of the adaptive filtering method for GPS circuit of the present invention is shown.

[0023] like Figure 1 As shown, the first aspect of the present invention discloses an adaptive filtering method for a GPS circuit, the method comprising: S102, obtaining a first radio frequency signal received by a GPS antenna; S104: Obtain an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm; S106: Acquire a first frequency point and obtain an interference threshold corresponding to the first frequency point; S108, determining interference energy at a first frequency point according to the interference energy distribution spectrum; S110, if the interference energy exceeds the interference threshold, mark it as an interference frequency point; S112, matching a preset interference library according to the interference frequency; S114, if it is the first interference frequency point, activate the corresponding fixed band-stop unit; S116, if it is a second interference frequency point, dynamically calculating LC parameters according to the interference frequency point, for configuring the programmable resonant unit; S118, calculating an optimization index based on a preset iteration period and the signal-to-noise ratio before and after filtering; S120: If the optimization index is lower than a preset index threshold, triggering an LC parameter update mechanism.

[0024] It should be noted that the first radio frequency signal is the radio frequency signal received by the GPS antenna; the first frequency point is the typical value of the preset interference frequency point; the first interference frequency point represents a known interference frequency point; and the second interference frequency point represents an unknown interference frequency point. This embodiment provides an adaptive filtering method for a GPS circuit. In this embodiment, first, a radio frequency signal containing interference is received by the GPS antenna, and the wideband sampling circuit captures the 1.1-1.7GHz full-band data. Real-time spectrum scanning is performed based on a preset acquisition period, and high-energy frequency points outside the GPS frequency band are identified through an energy peak detection algorithm, marked as interference frequencies, and their corresponding interference energy is recorded. The system compares the interference energy of each group of interference frequencies with a preset threshold. If the interference energy exceeds the set threshold, it is marked as an interference frequency point. Then, the interference library matching is started: if the interference frequency belongs to a known interference frequency, the corresponding fixed band-stop unit is activated, where the commonly known interference frequencies are the second harmonics of Band13 (1496MHz) and Band14 (1582MHz); if the interference frequency belongs to an unknown interference frequency, the LC parameters are dynamically calculated and the programmable resonant unit is configured to suppress the interference energy of the unknown interference frequency. The filtered signal is input into the GPS chip, and the effect is verified by monitoring the carrier-to-noise ratio. The optimization index is calculated based on the signal-to-noise ratio before and after filtering. If the optimization index is lower than the preset index threshold, the iterative optimization of the LC parameters is triggered until the positioning stability meets the standard. This embodiment realizes dynamic adjustment from interference perception to suppression, solving the pain point that traditional fixed filtering cannot cope with sudden interference.

[0025] Figure 2 A flowchart for constructing an interference energy distribution spectrum provided by an embodiment of the present invention is shown.

[0026] According to an embodiment of the present invention, Figure 2 As shown, the preset energy peak detection algorithm is used to obtain the interference energy distribution spectrum according to the first radio frequency signal, specifically including: S202, in response to a preset first band-stop filter, obtaining a first interference signal according to the first radio frequency signal; S204, dividing the first interference signal into sub-channels with the first frequency point as the center frequency based on a preset frequency band window; S206, calculating the root mean square value of the signal energy in each sub-channel based on the first interference signal to obtain interference energy; S208: compose the interference energy distribution spectrum according to the first frequency point and the interference energy.

[0027] It should be noted that this embodiment provides a process for constructing an interference energy distribution spectrum. First, the original RF signal is passed through a preset broadband filter to separate the interference components outside the GPS frequency band to obtain the original interference signal. The original interference signal is divided into several sub-channels with a set step. As an implementation method, taking 25MHz compensation as an example, the interval [1550Mhz, 1575MHz] is a sub-channel. Each sub-channel uses a sliding window to sample the signal, and the root mean square value of the signal within the window is eliminated after eliminating the influence of transient noise to generate energy data. The system constructs a frequency-energy mapping table, for example, the energy at 1500MHz is -45dBm, and at 1575MHz is -42dBm. The distribution spectrum is stored in a two-dimensional matrix, with the horizontal axis being frequency and the vertical axis being energy intensity, to generate an interference energy distribution spectrum for subsequent interference feature matching. This embodiment implements local analysis of RF signals and uses sub-channel subdivision to avoid misjudgment caused by frequency band overlap.

[0028] Figure 3 A matching flow chart of an interference library provided by an embodiment of the present invention is shown.

[0029] According to an embodiment of the present invention, Figure 3 As shown, the preset interference library is matched according to the interference frequency, specifically: S302, obtaining a first characteristic frequency point and a second characteristic frequency point according to the interference library; S304, determining whether the interference frequency is a first characteristic frequency; S306: If yes, determine that the interference frequency is the first interference frequency; S308, if not, determining that the interference frequency is a second interference frequency; S310: If the interference frequency point is a second characteristic frequency point, output characteristic LC parameters.

[0030] It should be noted that this embodiment provides an interference library matching mechanism. The first characteristic frequency points represent typical values ​​of interference frequencies, which in this embodiment include Band 13 (1496MHz) and Band 14 (1582MHz). The second characteristic frequency points represent frequently occurring interference frequencies recorded by the interference library. This embodiment loads characteristic frequency data from a preset interference library, which includes the first and second characteristic frequencies. The marked interference frequencies are compared item by item with the characteristic library. If the interference frequency falls within the first characteristic frequency point, it is determined to be Class I interference, i.e., known interference. For known interference, this type of interference is suppressed by activating the corresponding fixed band-stop unit. If the interference frequency does not fall within the first characteristic frequency point, it is classified as Class II interference, i.e., unknown interference. For unknown interference, if the interference frequency falls within the second characteristic frequency point, the associated LC parameter combination is directly invoked. For interference frequencies that do not fall within the second characteristic frequency point, the LC parameters are dynamically calculated based on the interference frequency. The programmable resonant unit is configured based on the LC parameters to suppress the unknown interference. This embodiment adopts dual-mode interference processing to improve the response speed for known interference and initiate dynamic calculation for unknown interference; in addition, pre-stored LC parameters are used to reduce calculation delay and significantly shorten positioning convergence time.

[0031] According to an embodiment of the present invention, if the first interference frequency point is present, activating the corresponding fixed band-stop unit is specifically as follows: If the first interference frequency corresponds to a preset first harmonic interference, turning on the first series resonant circuit; If the first interference frequency corresponds to a preset second harmonic interference, activating the first parallel resonant network; Obtaining an auxiliary frequency band according to the first interference frequency point; According to the auxiliary frequency band, a corresponding notch filter is activated.

[0032] It should be noted that this embodiment provides a static suppression process for known interference frequencies. The first harmonic interference is Band13 harmonic; the second harmonic interference is Band14 harmonic. When it is identified as the first harmonic interference Band13 harmonic, the MOSFET switch is controlled to turn on the 1496MHz series resonant circuit, forming a >20dB deep band stop at the resonance point. When it is identified as the second harmonic interference Band14 harmonic, the 1582MHz parallel resonant network is enabled, forming a >20dB deep band stop at the resonance point. Synchronously analyze the interference spectrum characteristics, identify the harmonic sidelobe frequency band, including the ±15MHz range of Band13 or the ±12MHz range of Band14, and activate the auxiliary notch filter to enhance the suppression bandwidth. This embodiment uses a main resonant circuit combined with an auxiliary notch filter to form a master-slave suppression chain, improve the harmonic suppression depth, and reduce and eliminate the positioning drift phenomenon caused by base station harmonics.

[0033] According to an embodiment of the present invention, dynamically calculating LC parameters according to the interference frequency point for configuring a programmable resonant unit specifically includes: Obtaining a band-stop frequency range and a target suppression depth according to the interference frequency and the interference energy; According to the band-stop frequency range, a preset initial combination of LC values ​​is selected, and the LC values ​​are iteratively optimized based on the gradient descent method until the target suppression depth is met, thereby obtaining LC parameters; Writing the C parameter of the LC parameter into the register of the digitally controlled capacitor array; The switch coding of the inductor matrix is ​​set according to the L parameter of the LC parameter.

[0034] It should be noted that this embodiment provides a dynamic suppression process for unknown interference frequencies. For unknown interference frequencies, the bandwidth where the interference energy exceeds -3dB is analyzed, and the target suppression depth is calculated. The initial LC combination is selected. As an implementation method, the standard inductor library is 2.7nH or 3.3nH, and the standard capacitor array is 1.5-2.2pF. Then, iterative optimization is performed based on the gradient descent method: the inductor L or capacitor C value is fine-tuned at each step and the band-stop characteristics are simulated until the suppression depth reaches the standard. The optimal capacitance value is converted into binary code and written into the digitally controlled capacitor array register, and the inductance value is physically reconstructed through matrix switch encoding. Finally, a test signal is injected to verify the band-stop characteristics. If the suppression depth is <15dB, the parameters are re-optimized. This embodiment solves the problem of real-time suppression of unknown interference through dynamic parameter optimization.

[0035] According to an embodiment of the present invention, the triggering LC parameter update mechanism specifically includes: Detect and obtain the unsuppressed residual interference frequency and its residual interference energy; Obtaining a frequency offset according to the residual interference frequency and the LC parameter; If the frequency offset exceeds a preset offset threshold, re-iteratively optimizing the LC value; If the residual interference energy exceeds a preset energy threshold, the number of capacitor array stages is increased.

[0036] It should be noted that this embodiment provides a filtering result verification mechanism, which triggers the LC parameter update based on the filtering verification result. When the optimization index after filtering is lower than the threshold, the residual interference spectrum data is collected, the unsuppressed frequency point is located and its energy intensity is measured. The frequency offset between the actual suppressed frequency point and the target frequency point is calculated. If the frequency offset exceeds the preset offset threshold, usually with a deviation range of 1MHz, the gradient descent method is re-executed to optimize the LC parameters. If the residual interference energy exceeds the set energy threshold, as an implementation method, with -45dBm as the reference standard, the number of capacitor array levels is increased to expand the stop band, for example, from a 4-level capacitor array to a 6-level capacitor array. At the same time, cross-unit collaboration is started, and the fixed band-stop unit and the programmable unit are connected in parallel to generate a composite response curve. This embodiment adopts a dual-threshold error correction mechanism, optimizes the LC parameters based on frequency offset to ensure narrowband suppression accuracy, and responds to broadband interference by expanding the number of capacitor array levels.

[0037] It is worth mentioning that it also includes the interference library dynamic update logic, specifically: When the interference frequency point fails to match the interference library, it is determined to be an unknown interference frequency point; If the number of consecutive occurrences of the unknown interference frequency point of the same frequency exceeds a preset number threshold, the unknown interference frequency point is marked as a second characteristic frequency point; If the optimization index corresponding to the iterative LC parameter of the second characteristic frequency point exceeds a preset index threshold, the LC parameter is recorded as a characteristic LC parameter of the second characteristic frequency point.

[0038] It should be noted that this embodiment provides a self-learning mechanism for an interference library. Interference frequencies that are not successfully matched are marked as unknown interference frequencies, and LC dynamic calculation is started. When the unknown interference frequency of the same frequency appears more than three times in a row and the optimization index of the dynamic filtering based on the LC parameters meets the standard, the frequency is marked as the second characteristic frequency and added to the interference library, and the successfully suppressed LC parameter combination is stored as a characteristic parameter, for example, 1587MHz corresponds to 3.0nH+2.1pF. When similar interference is encountered subsequently, the characteristic parameters are directly called and the dynamic calculation link is skipped. In addition, based on the preset validity verification cycle, the validity of the newly added characteristic frequencies is counted, and redundant parameters with low usage are eliminated to achieve intelligent evolution of the interference library.

[0039] It is worth mentioning that a phase compensation mechanism is also included, specifically including: Calculate the phase deviation between the interference frequency and the local clock; Calculating a compensation frequency based on the phase deviation based on a preset noise compensation algorithm; According to the compensation frequency, phase compensation harmonics are injected through the programmable resonance unit.

[0040] It should be noted that this embodiment provides a phase compensation mechanism. This embodiment uses a zero-point detection circuit to compare the phase difference between the interference signal and the GPS local clock. As an implementation method, especially in high-speed mobile scenarios, if a 15° phase lag is detected in the 1580MHz interference, the system calculates the compensation parameters: a harmonic signal with equal amplitude and 15° phase lead is generated. This signal is generated by the digitally controlled oscillator of the programmable resonant unit, and is injected into the RF path after DAC conversion to offset the phase noise of the original interference. The compensation amount is dynamically adjusted with the environment, and the compensation parameters are smoothed based on the set period to avoid signal distortion caused by over-correction. This embodiment significantly reduces the positioning drift problem in high-speed mobile scenarios through the above-mentioned phase compensation mechanism.

[0041] Figure 4 A block diagram of an adaptive filtering system for a GPS circuit according to the present invention is shown.

[0042] like Figure 4 As shown, the second aspect of the present invention discloses an adaptive filtering system 4 for a GPS circuit, comprising a memory 41 and a processor 42. The memory includes an adaptive filtering method program for a GPS circuit. When the adaptive filtering method program for a GPS circuit is executed by the processor, the following steps are implemented: Acquire a first radio frequency signal received by a GPS antenna; Obtaining an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm; Obtaining a first frequency point, and obtaining an interference threshold corresponding to the first frequency point; Determining interference energy at a first frequency point according to the interference energy distribution spectrum; If the interference energy exceeds the interference threshold, it is marked as an interference frequency point; According to the interference frequency, matching a preset interference library; If it is the first interference frequency, the corresponding fixed band-stop unit is activated; If it is the second interference frequency point, dynamically calculating the LC parameters according to the interference frequency point for configuring the programmable resonant unit; Based on the preset iteration cycle, the optimization index is calculated according to the signal-to-noise ratio before and after filtering; If the optimization index is lower than a preset index threshold, the LC parameter update mechanism is triggered.

[0043] It should be noted that the first radio frequency signal is the radio frequency signal received by the GPS antenna; the first frequency point is the typical value of the preset interference frequency point; the first interference frequency point represents a known interference frequency point; and the second interference frequency point represents an unknown interference frequency point. This embodiment provides an adaptive filtering method for a GPS circuit. In this embodiment, first, a radio frequency signal containing interference is received by the GPS antenna, and the wideband sampling circuit captures the 1.1-1.7GHz full-band data. Real-time spectrum scanning is performed based on a preset acquisition period, and high-energy frequency points outside the GPS frequency band are identified through an energy peak detection algorithm, marked as interference frequencies, and their corresponding interference energy is recorded. The system compares the interference energy of each group of interference frequencies with a preset threshold. If the interference energy exceeds the set threshold, it is marked as an interference frequency point. Then, the interference library matching is started: if the interference frequency belongs to a known interference frequency, the corresponding fixed band-stop unit is activated, where the commonly known interference frequencies are the second harmonics of Band13 (1496MHz) and Band14 (1582MHz); if the interference frequency belongs to an unknown interference frequency, the LC parameters are dynamically calculated and the programmable resonant unit is configured to suppress the interference energy of the unknown interference frequency. The filtered signal is input into the GPS chip, and the effect is verified by monitoring the carrier-to-noise ratio. The optimization index is calculated based on the signal-to-noise ratio before and after filtering. If the optimization index is lower than the preset index threshold, the iterative optimization of the LC parameters is triggered until the positioning stability meets the standard. This embodiment realizes dynamic adjustment from interference perception to suppression, solving the pain point that traditional fixed filtering cannot cope with sudden interference.

[0044] According to an embodiment of the present invention, obtaining an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm specifically includes: In response to a preset first band-stop filter, obtaining a first interference signal according to the first radio frequency signal; Based on a preset frequency band window, the first interference signal is divided into sub-channels with the first frequency point as the center frequency; Calculating the root mean square value of the signal energy in each sub-channel according to the first interference signal to obtain interference energy; The interference energy distribution spectrum is composed according to the first frequency point and the interference energy.

[0045] It should be noted that this embodiment provides a process for constructing an interference energy distribution spectrum. First, the original RF signal is passed through a preset broadband filter to separate the interference components outside the GPS frequency band to obtain the original interference signal. The original interference signal is divided into several sub-channels with a set step. As an implementation method, taking 25MHz compensation as an example, the interval [1550Mhz, 1575MHz] is a sub-channel. Each sub-channel uses a sliding window to sample the signal, and the root mean square value of the signal within the window is eliminated after eliminating the influence of transient noise to generate energy data. The system constructs a frequency-energy mapping table, for example, the energy at 1500MHz is -45dBm, and at 1575MHz is -42dBm. The distribution spectrum is stored in a two-dimensional matrix, with the horizontal axis being frequency and the vertical axis being energy intensity, to generate an interference energy distribution spectrum for subsequent interference feature matching. This embodiment implements local analysis of RF signals and uses sub-channel subdivision to avoid misjudgment caused by frequency band overlap.

[0046] According to an embodiment of the present invention, matching a preset interference library according to the interference frequency point is specifically: Obtaining a first characteristic frequency point and a second characteristic frequency point according to the interference library; Determining whether the interference frequency point is a first characteristic frequency point; If yes, determining that the interference frequency is the first interference frequency; If not, determining that the interference frequency is the second interference frequency; If the interference frequency point is the second characteristic frequency point, the characteristic LC parameter is output.

[0047] It should be noted that this embodiment provides an interference library matching mechanism. The first characteristic frequency points represent typical values ​​of interference frequencies, which in this embodiment include Band 13 (1496MHz) and Band 14 (1582MHz). The second characteristic frequency points represent frequently occurring interference frequencies recorded by the interference library. This embodiment loads characteristic frequency data from a preset interference library, which includes the first and second characteristic frequencies. The marked interference frequencies are compared item by item with the characteristic library. If the interference frequency falls within the first characteristic frequency point, it is determined to be Class I interference, i.e., known interference. For known interference, this type of interference is suppressed by activating the corresponding fixed band-stop unit. If the interference frequency does not fall within the first characteristic frequency point, it is classified as Class II interference, i.e., unknown interference. For unknown interference, if the interference frequency falls within the second characteristic frequency point, the associated LC parameter combination is directly invoked. For interference frequencies that do not fall within the second characteristic frequency point, the LC parameters are dynamically calculated based on the interference frequency. The programmable resonant unit is configured based on the LC parameters to suppress the unknown interference. This embodiment adopts dual-mode interference processing to improve the response speed for known interference and initiate dynamic calculation for unknown interference; in addition, pre-stored LC parameters are used to reduce calculation delay and significantly shorten positioning convergence time.

[0048] According to an embodiment of the present invention, if the first interference frequency point is present, activating the corresponding fixed band-stop unit is specifically as follows: If the first interference frequency corresponds to a preset first harmonic interference, turning on the first series resonant circuit; If the first interference frequency corresponds to a preset second harmonic interference, activating the first parallel resonant network; Obtaining an auxiliary frequency band according to the first interference frequency point; According to the auxiliary frequency band, a corresponding notch filter is activated.

[0049] It should be noted that this embodiment provides a static suppression process for known interference frequencies. The first harmonic interference is Band13 harmonic; the second harmonic interference is Band14 harmonic. When it is identified as the first harmonic interference Band13 harmonic, the MOSFET switch is controlled to turn on the 1496MHz series resonant circuit, forming a >20dB deep band stop at the resonance point. When it is identified as the second harmonic interference Band14 harmonic, the 1582MHz parallel resonant network is enabled, forming a >20dB deep band stop at the resonance point. Synchronously analyze the interference spectrum characteristics, identify the harmonic sidelobe frequency band, including the ±15MHz range of Band13 or the ±12MHz range of Band14, and activate the auxiliary notch filter to enhance the suppression bandwidth. This embodiment uses a main resonant circuit combined with an auxiliary notch filter to form a master-slave suppression chain, improve the harmonic suppression depth, and reduce and eliminate the positioning drift phenomenon caused by base station harmonics.

[0050] According to an embodiment of the present invention, dynamically calculating LC parameters according to the interference frequency point for configuring a programmable resonant unit specifically includes: Obtaining a band-stop frequency range and a target suppression depth according to the interference frequency and the interference energy; According to the band-stop frequency range, a preset initial combination of LC values ​​is selected, and the LC values ​​are iteratively optimized based on the gradient descent method until the target suppression depth is met, thereby obtaining LC parameters; Writing the C parameter of the LC parameter into the register of the digitally controlled capacitor array; The switch coding of the inductor matrix is ​​set according to the L parameter of the LC parameter.

[0051] It should be noted that this embodiment provides a dynamic suppression process for unknown interference frequencies. For unknown interference frequencies, the bandwidth where the interference energy exceeds -3dB is analyzed, and the target suppression depth is calculated. The initial LC combination is selected. As an implementation method, the standard inductor library is 2.7nH or 3.3nH, and the standard capacitor array is 1.5-2.2pF. Then, iterative optimization is performed based on the gradient descent method: the inductor L or capacitor C value is fine-tuned at each step and the band-stop characteristics are simulated until the suppression depth reaches the standard. The optimal capacitance value is converted into binary code and written into the digitally controlled capacitor array register, and the inductance value is physically reconstructed through matrix switch encoding. Finally, a test signal is injected to verify the band-stop characteristics. If the suppression depth is <15dB, the parameters are re-optimized. This embodiment solves the problem of real-time suppression of unknown interference through dynamic parameter optimization.

[0052] According to an embodiment of the present invention, the triggering LC parameter update mechanism specifically includes: Detect and obtain the unsuppressed residual interference frequency and its residual interference energy; Obtaining a frequency offset according to the residual interference frequency and the LC parameter; If the frequency offset exceeds a preset offset threshold, re-iteratively optimizing the LC value; If the residual interference energy exceeds a preset energy threshold, the number of capacitor array stages is increased.

[0053] It should be noted that this embodiment provides a filtering result verification mechanism, which triggers the LC parameter update based on the filtering verification result. When the optimization index after filtering is lower than the threshold, the residual interference spectrum data is collected, the unsuppressed frequency point is located and its energy intensity is measured. The frequency offset between the actual suppressed frequency point and the target frequency point is calculated. If the frequency offset exceeds the preset offset threshold, usually with a deviation range of 1MHz, the gradient descent method is re-executed to optimize the LC parameters. If the residual interference energy exceeds the set energy threshold, as an implementation method, with -45dBm as the reference standard, the number of capacitor array levels is increased to expand the stop band, for example, from a 4-level capacitor array to a 6-level capacitor array. At the same time, cross-unit collaboration is started, and the fixed band-stop unit and the programmable unit are connected in parallel to generate a composite response curve. This embodiment adopts a dual-threshold error correction mechanism, optimizes the LC parameters based on frequency offset to ensure narrowband suppression accuracy, and responds to broadband interference by expanding the number of capacitor array levels.

[0054] It is worth mentioning that it also includes the interference library dynamic update logic, specifically: When the interference frequency point fails to match the interference library, it is determined to be an unknown interference frequency point; If the number of consecutive occurrences of the unknown interference frequency point of the same frequency exceeds a preset number threshold, the unknown interference frequency point is marked as a second characteristic frequency point; If the optimization index corresponding to the iterative LC parameter of the second characteristic frequency point exceeds a preset index threshold, the LC parameter is recorded as a characteristic LC parameter of the second characteristic frequency point.

[0055] It should be noted that this embodiment provides a self-learning mechanism for an interference library. Interference frequencies that are not successfully matched are marked as unknown interference frequencies, and LC dynamic calculation is started. When the unknown interference frequency of the same frequency appears more than three times in a row and the optimization index of the dynamic filtering based on the LC parameters meets the standard, the frequency is marked as the second characteristic frequency and added to the interference library, and the successfully suppressed LC parameter combination is stored as a characteristic parameter, for example, 1587MHz corresponds to 3.0nH+2.1pF. When similar interference is encountered subsequently, the characteristic parameters are directly called and the dynamic calculation link is skipped. In addition, based on the preset validity verification cycle, the validity of the newly added characteristic frequencies is counted, and redundant parameters with low usage are eliminated to achieve intelligent evolution of the interference library.

[0056] It is worth mentioning that a phase compensation mechanism is also included, specifically including: Calculate the phase deviation between the interference frequency and the local clock; Calculating a compensation frequency based on the phase deviation based on a preset noise compensation algorithm; According to the compensation frequency, phase compensation harmonics are injected through the programmable resonance unit.

[0057] It should be noted that this embodiment provides a phase compensation mechanism. This embodiment uses a zero-point detection circuit to compare the phase difference between the interference signal and the GPS local clock. As an implementation method, especially in high-speed mobile scenarios, if a 15° phase lag is detected in the 1580MHz interference, the system calculates the compensation parameters: a harmonic signal with equal amplitude and 15° phase lead is generated. This signal is generated by the digitally controlled oscillator of the programmable resonant unit, and is injected into the RF path after DAC conversion to offset the phase noise of the original interference. The compensation amount is dynamically adjusted with the environment, and the compensation parameters are smoothed based on the set period to avoid signal distortion caused by over-correction. This embodiment significantly reduces the positioning drift problem in high-speed mobile scenarios through the above-mentioned phase compensation mechanism.

[0058] A third aspect of the present invention provides a computer-readable storage medium, which includes an adaptive filtering method program for a GPS circuit. When the adaptive filtering method program for a GPS circuit is executed by a processor, the steps of the adaptive filtering method for a GPS circuit as described in any one of the above items are implemented.

[0059] In summary, the present invention provides an adaptive filtering method, system and storage medium for GPS circuits, which scans the GPS radio frequency signal in real time through wide-band radio frequency sampling, and obtains the interference energy distribution spectrum based on the energy peak detection algorithm; determines the interference energy based on the preset frequency point to match the preset interference library; if the match is a known interference frequency point, activates the preset fixed band-stop unit; if the match is an unknown interference frequency point, dynamically calculates the LC parameters, configures the programmable resonant unit, and realizes dynamic suppression of the interference signal; verifies the signal-to-noise ratio based on the preset period, calculates the optimization index, and triggers the iterative update of the LC parameters if the optimization index is insufficient until the positioning is stable; provides core technical support for high-precision positioning scenarios.

[0060] If the functions are implemented as software modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or the portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0061] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An adaptive filtering method for GPS circuit, characterized in that: The method comprises: Acquire a first radio frequency signal received by a GPS antenna; Obtaining an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm; Obtain a first frequency point, and obtain an interference threshold corresponding to the first frequency point; Determining interference energy at a first frequency point according to the interference energy distribution spectrum; If the interference energy exceeds the interference threshold, it is marked as an interference frequency point; According to the interference frequency, matching a preset interference library; If it is the first interference frequency, the corresponding fixed band-stop unit is activated; If it is the second interference frequency point, dynamically calculating the LC parameters according to the interference frequency point for configuring the programmable resonant unit; Based on the preset iteration cycle, the optimization index is calculated according to the signal-to-noise ratio before and after filtering; If the optimization index is lower than a preset index threshold, the LC parameter update mechanism is triggered.

2. The adaptive filtering method for GPS circuit according to claim 1, wherein: The obtaining of an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm specifically includes: In response to a preset first band-stop filter, obtaining a first interference signal according to the first radio frequency signal; Based on a preset frequency band window, the first interference signal is divided into sub-channels with the first frequency point as the center frequency; Calculating the root mean square value of the signal energy in each sub-channel according to the first interference signal to obtain interference energy; The interference energy distribution spectrum is composed according to the first frequency point and the interference energy.

3. The adaptive filtering method for GPS circuit according to claim 1, characterized in that: The matching of the preset interference library according to the interference frequency is specifically as follows: Obtaining a first characteristic frequency point and a second characteristic frequency point according to the interference library; Determining whether the interference frequency point is a first characteristic frequency point; If yes, determining that the interference frequency is the first interference frequency; If not, determining that the interference frequency is the second interference frequency; If the interference frequency point is the second characteristic frequency point, the characteristic LC parameter is output.

4. The adaptive filtering method for GPS circuit according to claim 1, characterized in that: If it is the first interference frequency point, the corresponding fixed band-stop unit is activated, specifically: If the first interference frequency corresponds to a preset first harmonic interference, turning on the first series resonant circuit; If the first interference frequency corresponds to a preset second harmonic interference, activating the first parallel resonant network; Obtaining an auxiliary frequency band according to the first interference frequency point; According to the auxiliary frequency band, a corresponding notch filter is activated.

5. The adaptive filtering method for GPS circuit according to claim 1, characterized in that: The dynamically calculating LC parameters according to the interference frequency point for configuring the programmable resonant unit specifically includes: Obtaining a band-stop frequency range and a target suppression depth according to the interference frequency and the interference energy; According to the band-stop frequency range, a preset initial combination of LC values ​​is selected, and the LC values ​​are iteratively optimized based on the gradient descent method until the target suppression depth is met, thereby obtaining LC parameters; Writing the C parameter of the LC parameter into the register of the digitally controlled capacitor array; The switch coding of the inductor matrix is ​​set according to the L parameter of the LC parameter.

6. The adaptive filtering method for GPS circuit according to claim 1, characterized in that: The triggering LC parameter update mechanism specifically includes: Detect and obtain the unsuppressed residual interference frequency and its residual interference energy; Obtaining a frequency offset according to the residual interference frequency and the LC parameter; If the frequency offset exceeds a preset offset threshold, re-iteratively optimizing the LC value; If the residual interference energy exceeds a preset energy threshold, the number of capacitor array stages is increased.

7. An adaptive filtering system for GPS circuit, characterized in that: The system includes a memory and a processor. The memory includes an adaptive filtering method program for a GPS circuit. When the adaptive filtering method program for a GPS circuit is executed by the processor, the following steps are implemented: Acquire a first radio frequency signal received by a GPS antenna; Obtaining an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm; Obtain a first frequency point, and obtain an interference threshold corresponding to the first frequency point; Determining interference energy at a first frequency point according to the interference energy distribution spectrum; If the interference energy exceeds the interference threshold, it is marked as an interference frequency point; According to the interference frequency, matching a preset interference library; If it is the first interference frequency, the corresponding fixed band-stop unit is activated; If it is the second interference frequency point, dynamically calculating the LC parameters according to the interference frequency point for configuring the programmable resonant unit; Based on the preset iteration cycle, the optimization index is calculated according to the signal-to-noise ratio before and after filtering; If the optimization index is lower than a preset index threshold, the LC parameter update mechanism is triggered.

8. The adaptive filtering system for GPS circuit according to claim 7, characterized in that: The obtaining of an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm specifically includes: In response to a preset first band-stop filter, obtaining a first interference signal according to the first radio frequency signal; Based on a preset frequency band window, the first interference signal is divided into sub-channels with the first frequency point as the center frequency; Calculating the root mean square value of the signal energy in each sub-channel according to the first interference signal to obtain interference energy; The interference energy distribution spectrum is composed according to the first frequency point and the interference energy.

9. The adaptive filtering system for GPS circuit according to claim 7, characterized in that: The matching of the preset interference library according to the interference frequency is specifically as follows: Obtaining a first characteristic frequency point and a second characteristic frequency point according to the interference library; Determining whether the interference frequency point is a first characteristic frequency point; If yes, determining that the interference frequency is the first interference frequency; If not, determining that the interference frequency is the second interference frequency; If the interference frequency point is the second characteristic frequency point, the characteristic LC parameter is output.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer-readable storage medium includes an adaptive filtering method program for a GPS circuit. When the adaptive filtering method program for a GPS circuit is executed by a processor, the steps of the adaptive filtering method for a GPS circuit as described in any one of claims 1 to 6 are implemented.

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