An adaptive filtering method, system, and storage medium for GPS circuitry

Abstract

The application provides an adaptive filtering method, system and storage medium for a GPS circuit, real-time scanning of a radio frequency signal of a GPS through wide-band radio frequency sampling, and obtaining an interference energy distribution spectrum based on an energy peak value detection algorithm; determining interference energy based on a preset frequency point, so as to match a preset interference library; if the matching is a known interference frequency point, activating a preset fixed band rejection unit, if the matching is an unknown interference frequency point, dynamically calculating LC parameters, configuring a programmable resonance unit, and realizing dynamic suppression of an interference signal; verifying a signal-to-noise ratio based on a preset period, calculating an optimization index, and if the optimization index is insufficient, triggering LC parameter iteration and updating until positioning is stable; and providing core technical support for a high-precision positioning scene.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of GPS circuit, more particularly, to an adaptive filtering method, system and storage medium for GPS circuit. BACKGROUND

[0002] With the popularity of vehicle navigation, unmanned aerial vehicles and Internet of Things devices, GPS positioning reliability is facing severe challenges. The existing technology generally adopts a static filtering scheme of fixed LC circuit combined with SAW filter, which has problems of rigid anti-interference ability, lack of response mechanism for unknown interference, poor environmental adaptability and unbalanced energy efficiency. The traditional filtering circuit can only suppress preset frequency point interference, such as 1575MHz main frequency interference signal, but it is invalid for new interference signals such as Band13 (1496MHz) and Band14 (1582MHz) second harmonic. Such interference in urban areas with dense base stations causes a serious decline in signal-to-noise ratio, leading to frequent loss of stars. The static LC circuit cannot respond to sudden interference, and positioning inaccuracy may occur in areas such as airports and factories, which requires manual reset. In addition, fixed filtering parameters ignore the influence of temperature drift and device aging, resulting in a shift in the stopband frequency, especially in high-speed mobile scenarios, the probability of filtering failure is high. At present, there is a method to improve the anti-interference ability by widening the stopband, but it introduces additional insertion loss, which increases the gain of the signal amplifier, and in turn causes a serious increase in power consumption.

[0003] In summary, the essence of the existing scheme is passive defense, while complex electromagnetic environments require a dynamic immune system. Therefore, there is an urgent need for an adaptive filtering technology for GPS circuit. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide an adaptive filtering method, system and storage medium for GPS circuit, which constructs a cooperative mechanism of interference awareness, dynamic suppression and closed-loop optimization; real-time scanning of interference signals is performed through wideband radio frequency sampling, and an interference energy distribution spectrum is generated based on an energy peak detection algorithm to accurately identify interference frequency points exceeding the threshold; for known interference, a preset fixed band rejection unit is activated, and for unknown interference, LC parameters are dynamically calculated to configure a programmable resonant unit to realize dynamic suppression of interference signals; based on a preset periodic verification of signal-to-noise ratio optimization degree, if the optimization index is insufficient, LC parameter iteration update is triggered until the positioning is stable; and the core technology is provided for high-precision positioning scenarios.

[0005] The first aspect of the present application provides an adaptive filtering method for GPS circuit, the method comprising:

[0006] acquiring a first radio frequency signal received by a GPS antenna;

[0007] According to the first radio frequency signal, an interference energy distribution spectrum is obtained based on a preset energy peak detection algorithm;

[0008] A first frequency point is obtained, and an interference threshold corresponding to the first frequency point is obtained;

[0009] According to the interference energy distribution spectrum, the interference energy of the first frequency point is determined;

[0010] If the interference energy exceeds the interference threshold, the first frequency point is marked as an interference frequency point;

[0011] According to the interference frequency point, a preset interference library is matched;

[0012] If it is a first interference frequency point, a corresponding fixed band rejection unit is activated;

[0013] If it is a second interference frequency point, LC parameters are dynamically calculated according to the interference frequency point, which are used to configure a programmable resonant unit;

[0014] Based on a preset iteration period, an optimization index is calculated according to the signal-to-noise ratio before and after filtering;

[0015] If the optimization index is lower than a preset index threshold, an LC parameter updating mechanism is triggered.

[0016] In the scheme, according to the first radio frequency signal, an interference energy distribution spectrum is obtained based on a preset energy peak detection algorithm, which specifically includes:

[0017] In response to a preset first band rejection filter, a first interference signal is obtained according to the first radio frequency signal;

[0018] Based on a preset frequency band window, the first interference signal is divided into sub-channels with a first frequency point as a center frequency;

[0019] According to the first interference signal, the root mean square value of the signal energy in each sub-channel is calculated to obtain the interference energy;

[0020] According to the first frequency point and the interference energy, the interference energy distribution spectrum is composed.

[0021] In the scheme, according to the interference frequency point, a preset interference library is matched, which specifically includes:

[0022] According to the interference library, a first characteristic frequency point and a second characteristic frequency point are obtained;

[0023] It is judged whether the interference frequency point is a first characteristic frequency point;

[0024] If yes, it is determined that the interference frequency point is a first interference frequency point;

[0025] If not, the interference frequency point is determined as a second interference frequency point;

[0026] If the interference frequency point is a second characteristic frequency point, a characteristic LC parameter is output.

[0027] In this scheme, if it is a first interference frequency point, a corresponding fixed band rejection unit is activated, specifically:

[0028] If the first interference frequency point corresponds to a preset first harmonic interference, a first series resonance circuit is turned on;

[0029] If the first interference frequency point corresponds to a preset second harmonic interference, a first parallel resonance network is enabled;

[0030] According to the first interference frequency point, an auxiliary frequency band is obtained;

[0031] According to the auxiliary frequency band, a corresponding wave trap is activated.

[0032] In this scheme, the LC parameter is dynamically calculated according to the interference frequency point, which is used to configure a programmable resonance unit, specifically including:

[0033] According to the interference frequency point and the interference energy, a band rejection frequency range and a target suppression depth are obtained;

[0034] According to the band rejection frequency range, a preset LC value initial combination is selected, and the LC value is iteratively optimized based on the gradient descent method until the target suppression depth is met, to obtain the LC parameter;

[0035] According to the C parameter of the LC parameter, a register of a digital controlled capacitor array is written;

[0036] According to the L parameter of the LC parameter, a switch code of an inductance matrix is set.

[0037] In this scheme, the LC parameter update mechanism is triggered, specifically including:

[0038] The residual interference frequency point and its residual interference energy are detected and obtained;

[0039] According to the residual interference frequency point and the LC parameter, a frequency offset is obtained;

[0040] If the frequency offset exceeds a preset offset threshold, the LC value is re-iteratively optimized;

[0041] If the residual interference energy exceeds a preset energy threshold, the number of capacitor array stages is increased.

[0042] The second aspect of the present application provides an adaptive filtering system for a GPS circuit, comprising an adaptive filtering method program for a GPS circuit, which realizes the following steps when executed by the processor:

[0043] Obtaining a first radio frequency signal received by a GPS antenna;

[0044] Based on a preset energy peak detection algorithm, obtaining an interference energy distribution spectrum from the first radio frequency signal;

[0045] Obtaining a first frequency point and obtaining an interference threshold corresponding to the first frequency point;

[0046] Determining the interference energy of the first frequency point according to the interference energy distribution spectrum;

[0047] If the interference energy exceeds the interference threshold, marking it as an interference frequency point;

[0048] Matching a preset interference library according to the interference frequency point;

[0049] If it is a first interference frequency point, activating the corresponding fixed band rejection unit;

[0050] If it is a second interference frequency point, dynamically calculating LC parameters according to the interference frequency point for configuring a programmable resonant unit;

[0051] Based on a preset iteration period, calculating an optimization index according to the signal-to-noise ratio before and after filtering;

[0052] If the optimization index is lower than a preset index threshold, triggering an LC parameter update mechanism.

[0053] In the present scheme, based on the preset energy peak detection algorithm, the interference energy distribution spectrum is obtained from the first radio frequency signal, specifically including:

[0054] In response to a preset first band rejection filter, a first interference signal is obtained from the first radio frequency signal;

[0055] 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;

[0056] According to the first interference signal, the root mean square value of the signal energy in each sub-channel is calculated to obtain the interference energy;

[0057] According to the first frequency point and the interference energy, the interference energy distribution spectrum is composed.

[0058] In the present scheme, the interference library is matched according to the interference frequency point, specifically:

[0059] According to the interference library, a first characteristic frequency point and a second characteristic frequency point are obtained;

[0060] It is judged whether the interference frequency point is the first characteristic frequency point;

[0061] If yes, it is determined that the interference frequency point is the first interference frequency point;

[0062] If no, it is determined that the interference frequency point is the second interference frequency point;

[0063] If the interference frequency point is the second characteristic frequency point, a characteristic LC parameter is output.

[0064] The third aspect of the present application provides a computer readable storage medium, the computer readable storage medium comprises a self-adaptive filtering method program for a GPS circuit, and the self-adaptive filtering method program for the GPS circuit is executed by a processor to realize the steps of the self-adaptive filtering method for the GPS circuit according to any one of the above.

[0065] The present application provides a self-adaptive filtering method, system and storage medium for a GPS circuit, which scans the radio frequency signal of the GPS in real time through wideband radio frequency sampling, analyzes the interference energy distribution spectrum based on an energy peak value detection algorithm, determines the interference energy based on a preset frequency point, matches the preset interference library, activates the preset fixed band rejection unit if the matching is a known interference frequency point, dynamically calculates the LC parameter if the matching is an unknown interference frequency point, configures the programmable resonant unit, realizes the dynamic suppression of the interference signal, verifies the signal-to-noise ratio based on a preset period, calculates the optimization index, triggers the LC parameter iteration update if the optimization index is insufficient, and stabilizes the positioning until the positioning is stable, thereby providing a core technical guarantee for high-precision positioning scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0066] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope.

[0067] Figure 1 A flow chart of a self-adaptive filtering method for a GPS circuit according to the present application is shown;

[0068] Figure 2 A construction flow chart of an interference energy distribution spectrum according to the present application is shown;

[0069] Figure 3 A matching flow chart of an interference library according to the present application is shown;

[0070] Figure 4 A block diagram of a self-adaptive filtering system for a GPS circuit according to the present application is shown. DETAILED DESCRIPTION

[0071] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application.

[0072] Unless otherwise defined, all terms (including technical and scientific terms) used in the embodiments of the present application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined in the embodiments of the present application.

[0073] The terms "first", "second", and similar terms used in the embodiments of the present application do not denote any order, quantity, or importance, but are used to distinguish different constituent parts. The terms "one", "a", or "the" and similar terms do not denote a quantity of one, but mean that there is at least one. Similarly, the terms "include" or "contain" and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The steps before or after the methods in the embodiments of the present application do not necessarily proceed in order. On the contrary, various steps can be processed in reverse order or simultaneously. Meanwhile, other operations can be added to these processes, or a step or several steps can be removed from these processes.

[0074] In addition, the functional modules in each embodiment of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0075] Figure 1 A flowchart of an adaptive filtering method for a GPS circuit is shown.

[0076] As shown in Figure 1 A first aspect of the present application discloses an adaptive filtering method for a GPS circuit, the method comprising:

[0077] S102, acquiring a first radio frequency signal received by a GPS antenna;

[0078] S104, obtaining an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm;

[0079] S106, obtaining a first frequency point and obtaining an interference threshold corresponding to the first frequency point;

[0080] S108, determining the interference energy of the first frequency point according to the interference energy distribution spectrum;

[0081] S110, if the interference energy exceeds the interference threshold, marking as an interference frequency point;

[0082] S112, matching a preset interference library according to the interference frequency point;

[0083] S114, if it is a first interference frequency point, activating a corresponding fixed band rejection unit;

[0084] S116, if it is a second interference frequency point, dynamically calculating LC parameters according to the interference frequency point for configuring a programmable resonant unit;

[0085] S118, calculating an optimization index based on a preset iteration period according to the signal-to-noise ratio before and after filtering;

[0086] S120, if the optimization index is lower than a preset index threshold, triggering an LC parameter updating mechanism.

[0087] It should be noted that the first radio frequency signal is a radio frequency signal received by the GPS antenna; the first frequency point is a typical value of a 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. The embodiment provides a self-adaptive filtering method of a GPS circuit. In the embodiment, first, a radio frequency signal containing interference is received by a GPS antenna, and 1.1-1.7 GHz full-band data is captured by a wide-band sampling circuit. Real-time spectrum scanning is performed based on a preset acquisition period, a high-energy frequency point outside a GPS frequency band is identified by an energy peak value detection algorithm, is marked as an interference frequency point, and corresponding interference energy is recorded. The system compares the interference energy of each group of interference frequency points with a preset threshold value, and if the interference energy exceeds the set threshold value, the interference frequency point is marked. Then, the interference library matching is started: if the interference frequency point belongs to a known interference frequency point, the corresponding fixed band-stop unit is activated, wherein the common known interference frequency points are the second harmonics of Band 13 (1496 MHz) and Band 14 (1582 MHz); and if the interference frequency point belongs to an unknown interference frequency point, the LC parameters are dynamically calculated and the programmable resonant unit is configured to suppress the interference energy of the unknown interference frequency point. The filtered signal is input into a 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, and if the optimization index is lower than a preset index threshold value, the LC parameter iteration optimization is triggered until the positioning stability meets the standard. The embodiment realizes dynamic adjustment from interference sensing to suppression, and solves the pain point that the traditional fixed filtering cannot cope with sudden interference.

[0088] Figure 2 A flow chart of constructing an interference energy distribution spectrum is shown.

[0089] According to the embodiment of the present application, as Figure 2 shown, the preset energy peak value detection algorithm is used to obtain an interference energy distribution spectrum according to the first radio frequency signal, and specifically includes:

[0090] S202, a first interference signal is obtained according to the first radio frequency signal in response to a preset first band-stop filter;

[0091] S204, the first interference signal is divided into sub-channels with a first frequency point as a center frequency based on a preset frequency band window;

[0092] S206, the root mean square value of the signal energy in each sub-channel is calculated according to the first interference signal to obtain interference energy;

[0093] S208, the first frequency point and the interference energy are used to form the interference energy distribution spectrum.

[0094] It should be noted that the embodiment provides a construction process of the interference energy distribution spectrum, first, the original radio frequency signal is separated from the interference component outside the GPS frequency band through the filter of the preset wide band, and the original interference signal is obtained. The original interference signal is divided into a plurality of sub-channels by setting steps, as an embodiment, taking 25MHz compensation as an example, the interval [1550Mhz, 1575MHz] is a sub-channel. Each sub-channel adopts a sliding window for signal sampling, and the root mean square value of the signal in the window is generated after eliminating the influence of instantaneous noise. The system constructs a frequency point-energy mapping table, for example, the energy at 1500MHz is-45dBm, and the energy at 1575MHz is-42dBm. The distribution spectrum is stored by a two-dimensional matrix, the horizontal axis is the frequency, and the vertical axis is the energy intensity, an interference energy distribution spectrum is generated, which is used for subsequent interference feature matching. The embodiment realizes local analysis of the radio frequency signal, and adopts sub-channel subdivision to avoid misjudgment caused by frequency band overlap.

[0095] Figure 3 A matching flowchart of an interference library provided by the embodiment of the application is shown.

[0096] According to the embodiment of the application, as shown in Figure 3 According to the interference frequency point, the preset interference library is matched, specifically:

[0097] S302, according to the interference library, a first characteristic frequency point and a second characteristic frequency point are obtained;

[0098] S304, it is judged whether the interference frequency point is the first characteristic frequency point;

[0099] S306, if yes, it is determined that the interference frequency point is the first interference frequency point;

[0100] S308, if no, it is determined that the interference frequency point is the second interference frequency point;

[0101] S310, if the interference frequency point is the second characteristic frequency point, the characteristic LC parameter is output.

[0102] It should be noted that the embodiment provides an interference library matching mechanism. The first characteristic frequency point represents a typical value of an interference frequency point, and in the embodiment, includes Band 13 (1496 MHz) and Band 14 (1582 MHz); and the second characteristic frequency point represents a frequently occurring interference frequency point recorded by the interference library itself. The embodiment loads characteristic frequency point data from a preset interference library, which includes the first characteristic frequency point and the second characteristic frequency point. The marked interference frequency point is compared with the characteristic library item by item, if the interference frequency point falls into the first characteristic frequency point, it is determined as the first type of interference, that is, known interference. For the known interference, the corresponding fixed band rejection unit is activated to suppress such interference. If the interference frequency point does not fall into the first characteristic frequency point, it is classified as the second type of interference, that is, unknown interference. For the unknown interference, if the interference frequency point falls into the second characteristic frequency point, the associated LC parameter combination is directly called; and for the interference frequency point that does not fall into the second characteristic frequency point, the LC parameter is dynamically calculated based on the interference frequency point; and the programmable resonant unit is configured based on the LC parameter to suppress the unknown interference. The embodiment adopts a dual-mode interference processing, improves the response speed for the known interference, and starts dynamic calculation for the unknown interference; in addition, the pre-stored LC parameter is used to reduce the calculation delay, and the positioning convergence time is significantly shortened.

[0103] According to the embodiment of the application, if the first interference frequency point is activated, the corresponding fixed band rejection unit is activated, and specifically:

[0104] If the first interference frequency point corresponds to a preset first harmonic interference, the first series resonant circuit is turned on;

[0105] If the first interference frequency point corresponds to a preset second harmonic interference, the first parallel resonant network is enabled;

[0106] According to the first interference frequency point, an auxiliary frequency band is obtained;

[0107] According to the auxiliary frequency band, the corresponding wave trap is activated.

[0108] It should be noted that the embodiment provides a static suppression process for known interference frequency points. The first harmonic interference is Band 13 harmonic; the second harmonic interference is Band 14 harmonic. When the first harmonic interference Band 13 harmonic is identified, the MOSFET switch is controlled to be turned on to form a series resonance circuit of 1496MHz, and a >20dB deep band stop is formed at the resonance point. When the second harmonic interference Band 14 harmonic is identified, a parallel resonance network of 1582MHz is enabled, and a >20dB deep band stop is formed at the resonance point. The interference spectrum characteristics are analyzed synchronously, the harmonic sidelobe frequency band is identified, which includes the ±15MHz range of Band 13 or the ±12MHz range of Band 14, and the auxiliary wave trap is activated to enhance the suppression bandwidth. The embodiment adopts the master-slave suppression chain formed by the main resonance circuit combined with the auxiliary wave trap, improves the harmonic suppression depth, and reduces the positioning drift phenomenon caused by the base station harmonic.

[0109] According to the embodiment of the present application, the LC parameters are dynamically calculated according to the interference frequency point, and are used to configure a programmable resonance unit, and specifically include:

[0110] According to the interference frequency point and the interference energy, a band stop frequency range and a target suppression depth are obtained;

[0111] According to the band stop frequency range, a preset LC value initial combination is selected, and the LC value is iteratively optimized based on the gradient descent method until the target suppression depth is met, so as to obtain the LC parameters;

[0112] According to the C parameter of the LC parameter, a register of a digital controlled capacitor array is written;

[0113] According to the L parameter of the LC parameter, a switch code of an inductance matrix is set.

[0114] It should be noted that the embodiment provides a dynamic suppression process for unknown interference frequency points. For unknown interference frequency points, the bandwidth in which the interference energy exceeds-3dB is analyzed, and the target suppression depth is calculated. As an implementation, the standard inductance library is 2.7nH or 3.3nH, and the standard capacitor array is 1.5-2.2pF. Then, the gradient descent method is iteratively optimized: the inductance L or the capacitance C value is fine-tuned at each step, and the band stop characteristic is simulated until the suppression depth meets the standard. The optimal capacitance value is converted into a binary code and written into the register of the digital controlled capacitor array, and the inductance value is physically reconstructed by the matrix switch code. Finally, a test signal is injected to verify the band stop characteristic, and if the suppression depth is <15dB, the parameters are re-optimized. The embodiment solves the real-time suppression problem of unknown interference through dynamic parameter optimization.

[0115] According to the embodiment of the present application, the LC parameter update mechanism is triggered, and specifically includes:

[0116] detecting and acquiring the residual interference frequency point and its residual interference energy;

[0117] obtaining a frequency offset based on the residual interference frequency point and the LC parameter;

[0118] re-iterating and optimizing the LC value if the frequency offset exceeds a preset offset threshold;

[0119] increasing the number of the capacitor array if the residual interference energy exceeds a preset energy threshold.

[0120] It should be noted that the embodiment provides a filtering result verification mechanism, and LC parameter updating is triggered based on the filtering verification result. When the optimized index after filtering is lower than a threshold, residual interference frequency spectrum data is collected, the un-suppressed frequency point is located, and its energy strength is measured. The frequency offset between the actual suppressed frequency point and the target frequency point is calculated, and if the frequency offset exceeds a preset offset threshold, usually 1MHz as the deviation range, the gradient descent method is re-executed to optimize the LC parameter. If the residual interference energy exceeds a preset energy threshold, as an embodiment, -45dBm is used as a reference standard, the number of the capacitor array is increased to expand the stopband, for example, from 4-level capacitor array to 6-level capacitor array. At the same time, cross-cell cooperation is started, and a composite response curve is generated by connecting the fixed band-stop unit and the programmable unit in parallel. The embodiment adopts a double-threshold error correction mechanism, optimizes the LC parameter based on the frequency offset to guarantee the narrowband suppression accuracy, and deals with the wideband interference by expanding the number of the capacitor array.

[0121] It is worth mentioning that the interference library dynamic updating logic is also included, and specifically:

[0122] When the interference frequency point and the interference library are not matched successfully, it is determined as an unknown interference frequency point;

[0123] If the unknown interference frequency point at the same frequency appears continuously for more than a preset number of times, the unknown interference frequency point is marked as a second characteristic frequency point;

[0124] If the optimized index corresponding to the LC parameter of the second characteristic frequency point after iteration exceeds a preset index threshold, the LC parameter is recorded as the characteristic LC parameter of the second characteristic frequency point.

[0125] It should be noted that the embodiment provides a self-learning mechanism of the interference library. The interference frequency point that is not matched successfully is marked as an unknown interference frequency point, and LC dynamic calculation is started. When the unknown interference frequency point of the same frequency appears continuously more than 3 times and the optimization index of the dynamic filtering based on the LC parameter reaches the standard, the frequency point is marked as a second characteristic frequency point added to the interference library, and the LC parameter combination that is successfully suppressed is stored as a characteristic parameter, for example, 1587MHz corresponds to 3.0nH+2.1pF. When the same interference is encountered subsequently, the characteristic parameter is directly called, and the dynamic calculation link is skipped. In addition, based on the preset validity verification period, the effectiveness of the newly added characteristic frequency point is counted, the redundant parameters with low use rate are eliminated, and the intelligent evolution of the interference library is realized.

[0126] It is worth mentioning that a phase compensation mechanism is also included, which specifically includes:

[0127] The phase deviation of the interference frequency point and the local clock is calculated;

[0128] Based on a preset noise compensation algorithm, the compensation frequency is calculated according to the phase deviation;

[0129] According to the compensation frequency, a phase compensation harmonic is injected through a programmable resonant unit.

[0130] It should be noted that the embodiment provides a phase compensation mechanism. The embodiment compares the phase difference of the interference signal and the GPS local clock through a zero point detection circuit. As an implementation manner, especially in a high-speed mobile scene, if it is detected that the 1580MHz interference exists 15° phase lag, the system calculates the compensation parameter: a harmonic signal with equal amplitude and 15° phase lead is generated. The signal is generated by a digital control oscillator of a programmable resonant unit, and is injected into a radio frequency channel after DAC conversion to offset the phase noise of the original interference. The compensation amount is dynamically adjusted according to the environment, and the compensation parameter is smoothed based on a set period to avoid signal distortion caused by excessive correction. The embodiment significantly reduces the positioning drift problem in the high-speed mobile scene through the above-mentioned phase compensation mechanism.

[0131] Figure 4 A block diagram of an adaptive filtering system for a GPS circuit is shown.

[0132] As Figure 4 shown, the second aspect of the present application discloses an adaptive filtering system 4 for a GPS circuit, comprising a memory 41 and a processor 42, the memory comprising an adaptive filtering method program for a GPS circuit, the adaptive filtering method program for a GPS circuit being executed by the processor to implement the following steps:

[0133] Obtaining a first radio frequency signal received by a GPS antenna;

[0134] obtaining an interference energy distribution spectrum according to the first radio frequency signal based on a preset energy peak detection algorithm;

[0135] obtaining a first frequency point and obtaining an interference threshold corresponding to the first frequency point;

[0136] determining the interference energy of the first frequency point according to the interference energy distribution spectrum;

[0137] if the interference energy exceeds the interference threshold, marking the first frequency point as an interference frequency point;

[0138] matching a preset interference library according to the interference frequency point;

[0139] if the first interference frequency point, activating a corresponding fixed band rejection unit;

[0140] if the second interference frequency point, dynamically calculating LC parameters according to the interference frequency point for configuring a programmable resonant unit;

[0141] based on a preset iteration period, calculating an optimization index according to the signal-to-noise ratio before and after filtering;

[0142] if the optimization index is lower than a preset index threshold, triggering an LC parameter updating mechanism.

[0143] It should be noted that the first radio frequency signal is a radio frequency signal received by a GPS antenna; the first frequency point is a typical value of a 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. The embodiment provides a self-adaptive filtering method of a GPS circuit. In the embodiment, first, a radio frequency signal containing interference is received by a GPS antenna, and 1.1-1.7 GHz full-band data is captured by a wideband sampling circuit. Based on a preset acquisition period, real-time spectrum scanning is performed, a high-energy frequency point outside the GPS frequency band is identified by an energy peak detection algorithm, marked as an interference frequency point, and the corresponding interference energy is recorded. The system compares the interference energy of each group of interference frequency points with a preset threshold, and if the interference energy exceeds the set threshold, the interference frequency point is marked. Then, the interference library matching is started: if the interference frequency point belongs to a known interference frequency point, the corresponding fixed band rejection unit is activated, wherein the common known interference frequency points are the second harmonics of Band 13 (1496 MHz) and Band 14 (1582 MHz); if the interference frequency point belongs to an unknown interference frequency point, the LC parameters are dynamically calculated and the programmable resonant unit is configured to suppress the interference energy of the unknown interference frequency point. The filtered signal is input into a GPS chip, and the effect is verified by monitoring the carrier-to-noise ratio. Based on the signal-to-noise ratio before and after filtering, an optimization index is calculated, and if the optimization index is lower than a preset index threshold, an LC parameter iteration optimization is triggered until the positioning stability meets the standard. The embodiment realizes dynamic adjustment from interference perception to suppression, and solves the pain point that the traditional fixed filtering cannot cope with sudden interference.

[0144] According to the embodiment of the present application, the energy distribution spectrum is obtained according to the first radio frequency signal based on the preset energy peak detection algorithm, specifically comprising:

[0145] The first interference signal is obtained according to the first radio frequency signal in response to the preset first band-stop filter;

[0146] The first interference signal is divided into a sub-channel with the first frequency point as the center frequency based on the preset frequency band window;

[0147] The root mean square value of the signal energy in each sub-channel is calculated according to the first interference signal to obtain the interference energy;

[0148] The first frequency point and the interference energy are combined to form the interference energy distribution spectrum.

[0149] It should be noted that the embodiment provides a construction process of the interference energy distribution spectrum. First, the original radio frequency signal is separated from the interference component outside the GPS frequency band through a preset wideband filter to obtain an original interference signal. The original interference signal is divided into a plurality of sub-channels with a set step, and as an implementation manner, a 25MHz compensation is taken as an example, and the interval [1550Mhz, 1575MHz] is a sub-channel. Each sub-channel uses a sliding window for signal sampling, and the root mean square value of the signal in the window generates energy data after eliminating the influence of transient noise. A frequency point-energy mapping table is constructed by the system, for example, the energy at 1500MHz is-45dBm, and the energy at 1575MHz is-42dBm. The distribution spectrum is stored by a two-dimensional matrix, the horizontal axis is the frequency, and the vertical axis is the energy intensity, an interference energy distribution spectrum is generated, and is used for subsequent interference feature matching. The embodiment realizes local analysis of the radio frequency signal, and adopts sub-channel subdivision to avoid misjudgment caused by frequency band overlap.

[0150] According to the embodiment of the present application, the interference frequency point is matched with the preset interference library according to the interference frequency point, specifically comprising:

[0151] The first feature frequency point and the second feature frequency point are obtained according to the interference library;

[0152] It is judged whether the interference frequency point is the first feature frequency point;

[0153] If yes, it is determined that the interference frequency point is the first interference frequency point;

[0154] If no, it is determined that the interference frequency point is the second interference frequency point;

[0155] If the interference frequency point is the second feature frequency point, the feature LC parameter is output.

[0156] It should be noted that the embodiment provides an interference library matching mechanism. The first characteristic frequency point represents a typical value of an interference frequency point, and in the embodiment, includes Band 13 (1496 MHz) and Band 14 (1582 MHz); and the second characteristic frequency point represents a frequently occurring interference frequency point recorded by the interference library itself. The embodiment loads characteristic frequency point data from a preset interference library, which includes the first characteristic frequency point and the second characteristic frequency point. The marked interference frequency point is compared with the characteristic library item by item, if the interference frequency point falls into the first characteristic frequency point, it is determined as the first type of interference, that is, known interference. For the known interference, the corresponding fixed band rejection unit is activated to suppress such interference. If the interference frequency point does not fall into the first characteristic frequency point, it is classified as the second type of interference, that is, unknown interference. For the unknown interference, if the interference frequency point falls into the second characteristic frequency point, the associated LC parameter combination is directly called; and for the interference frequency point that does not fall into the second characteristic frequency point, the LC parameter is dynamically calculated based on the interference frequency point; and the programmable resonant unit is configured based on the LC parameter to suppress the unknown interference. The embodiment adopts a dual-mode interference processing, improves the response speed for the known interference, and starts dynamic calculation for the unknown interference; in addition, the pre-stored LC parameter is used to reduce the calculation delay, and the positioning convergence time is significantly shortened.

[0157] According to the embodiment of the application, if the first interference frequency point is activated, the corresponding fixed band rejection unit is activated, and specifically:

[0158] If the first interference frequency point corresponds to a preset first harmonic interference, the first series resonant circuit is turned on.

[0159] If the first interference frequency point corresponds to a preset second harmonic interference, the first parallel resonant network is enabled.

[0160] According to the first interference frequency point, an auxiliary frequency band is obtained.

[0161] According to the auxiliary frequency band, the corresponding wave trap is activated.

[0162] It should be noted that the embodiment provides a static suppression process for known interference frequency points. The first harmonic interference is Band 13 harmonic; the second harmonic interference is Band 14 harmonic. When the first harmonic interference Band 13 harmonic is identified, the MOSFET switch is controlled to be turned on to form a series resonance circuit of 1496MHz, and a >20dB deep band stop is formed at the resonance point. When the second harmonic interference Band 14 harmonic is identified, a parallel resonance network of 1582MHz is enabled, and a >20dB deep band stop is formed at the resonance point. The interference spectrum characteristics are analyzed synchronously, the harmonic sidelobe frequency band is identified, which includes the ±15MHz range of Band 13 or the ±12MHz range of Band 14, and the auxiliary wave trap is activated to enhance the suppression bandwidth. The embodiment adopts the master-slave suppression chain formed by the main resonance circuit combined with the auxiliary wave trap, improves the harmonic suppression depth, and reduces the positioning drift phenomenon caused by the base station harmonic.

[0163] According to the embodiment of the present application, the LC parameters are dynamically calculated according to the interference frequency point, and are used to configure a programmable resonance unit, and specifically include:

[0164] According to the interference frequency point and the interference energy, a band stop frequency range and a target suppression depth are obtained;

[0165] According to the band stop frequency range, a preset LC value initial combination is selected, and the LC value is iteratively optimized based on the gradient descent method until the target suppression depth is met, so as to obtain the LC parameters;

[0166] The C parameter of the LC parameter is written into the register of the digital control capacitor array;

[0167] The L parameter of the LC parameter is used to set the switch code of the inductance matrix.

[0168] It should be noted that the embodiment provides a dynamic suppression process for unknown interference frequency points. For unknown interference frequency points, the bandwidth in which the interference energy exceeds-3dB is analyzed, and the target suppression depth is calculated. As an implementation, the standard inductance library is 2.7nH or 3.3nH, and the standard capacitor array is 1.5-2.2pF. Then, the gradient descent method is used for iterative optimization: the inductance L or the capacitance C value is fine-tuned at each step, and the band stop characteristic is simulated until the suppression depth meets the standard. The optimal capacitance value is converted into binary code and written into the register of the digital control capacitor array, and the inductance value is physically reconstructed by the matrix switch code. Finally, the test signal is injected to verify the band stop characteristic, and if the suppression depth is less than 15dB, the parameters are re-optimized. The embodiment solves the real-time suppression problem of unknown interference through dynamic parameter optimization.

[0169] According to the embodiment of the present application, the LC parameter update mechanism is triggered, and specifically includes:

[0170] detecting and acquiring the residual interference frequency point and its residual interference energy;

[0171] obtaining a frequency offset based on the residual interference frequency point and the LC parameter;

[0172] re-iterating and optimizing the LC value if the frequency offset exceeds a preset offset threshold;

[0173] increasing the number of the capacitor array if the residual interference energy exceeds a preset energy threshold.

[0174] It should be noted that the embodiment provides a filter result verification mechanism, and LC parameter updating is triggered based on the filter verification result. When the optimized index after filtering is lower than a threshold, residual interference frequency spectrum data is collected, the un-suppressed frequency point is located, and its energy strength is measured. The frequency offset between the actual suppressed frequency point and the target frequency point is calculated. If the frequency offset exceeds a preset offset threshold, usually 1MHz as the deviation range, the gradient descent method is re-executed to optimize the LC parameter. If the residual interference energy exceeds a preset energy threshold, as an embodiment, -45dBm is used as a reference standard, the number of the capacitor array is increased to expand the stopband, for example, from 4-level capacitor array to 6-level capacitor array. At the same time, cross-cell cooperation is started, and a composite response curve is generated by connecting the fixed band-stop unit and the programmable unit in parallel. The embodiment adopts a double-threshold error correction mechanism, optimizes the LC parameter based on the frequency offset to guarantee the narrowband suppression accuracy, and deals with the wideband interference by expanding the number of the capacitor array.

[0175] It is worth mentioning that the interference library dynamic updating logic is also included, and specifically,

[0176] When the interference frequency point and the interference library are not matched successfully, it is determined as an unknown interference frequency point;

[0177] If the unknown interference frequency point at the same frequency appears continuously for more than a preset number of times, the unknown interference frequency point is marked as a second characteristic frequency point;

[0178] If the optimized index corresponding to the LC parameter of the second characteristic frequency point after iteration exceeds a preset index threshold, the LC parameter is recorded as the characteristic LC parameter of the second characteristic frequency point.

[0179] It should be noted that the embodiment provides a self-learning mechanism of the interference library. The interference frequency point that is not matched successfully is marked as an unknown interference frequency point, and the LC dynamic calculation is started. When the unknown interference frequency point of the same frequency appears continuously more than 3 times and the optimization index of the dynamic filtering based on the LC parameter meets the standard, the frequency point is marked as a second characteristic frequency point added to the interference library, and the LC parameter combination that is successfully suppressed is stored as a characteristic parameter, for example, 1587MHz corresponds to 3.0nH+2.1pF. When the same interference is encountered subsequently, the characteristic parameter is directly called, and the dynamic calculation link is skipped. In addition, based on the preset validity verification period, the effectiveness of the newly added characteristic frequency point is counted, the redundant parameters with low use rate are eliminated, and the intelligent evolution of the interference library is realized.

[0180] It is worth mentioning that a phase compensation mechanism is also included, specifically including:

[0181] The phase deviation of the interference frequency point and the local clock is calculated.

[0182] Based on a preset noise compensation algorithm, the compensation frequency is calculated according to the phase deviation.

[0183] According to the compensation frequency, a phase compensation harmonic is injected through a programmable resonant unit.

[0184] It should be noted that the embodiment provides a phase compensation mechanism. The embodiment compares the phase difference of the interference signal and the GPS local clock through the zero point detection circuit. As an implementation manner, especially in a high-speed moving scene, if it is detected that the 1580MHz interference exists 15° phase lag, the system calculates the compensation parameter: a harmonic signal with equal amplitude and 15° phase lead is generated. The signal is generated by the digital control oscillator of the programmable resonant unit, and is injected into the radio frequency channel after DAC conversion to offset the phase noise of the original interference. The compensation amount is dynamically adjusted according to the environment, and the compensation parameter is smoothed based on the set period to avoid signal distortion caused by excessive correction. The embodiment significantly reduces the positioning drift problem in the high-speed moving scene through the above-mentioned phase compensation mechanism.

[0185] The third aspect of the present application provides a computer readable storage medium, wherein the computer readable storage medium comprises a program of adaptive filtering method for GPS circuit, and the program of adaptive filtering method for GPS circuit is executed by a processor to realize the steps of the adaptive filtering method for GPS circuit according to any one of the above embodiments.

[0186] In summary, the application provides an adaptive filtering method, system and storage medium for a GPS circuit, which scans the radio frequency signal of GPS in real time through wideband radio frequency sampling, obtains the interference energy distribution spectrum based on an energy peak detection algorithm, determines the interference energy based on a preset frequency point, matches the preset interference library, activates the preset fixed band rejection unit if the matching is a known interference frequency point, dynamically calculates the LC parameter if the matching is an unknown interference frequency point, configures the programmable resonant unit, realizes dynamic suppression of the interference signal, verifies the signal-to-noise ratio based on a preset period, calculates the optimization index, triggers the LC parameter iterative update if the optimization index is insufficient, and stops until the positioning is stable, thereby providing core technical support for high-precision positioning scenarios.

[0187] If the functions are realized in the form of software function modules and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the application or the part of the prior art that essentially contributes or the part of the technical solutions can be embodied in the form of a software product, which is stored in a storage medium and includes instructions for making a computer device (which can be a personal computer, a server, or a network device) execute all or part of the steps of the method described in the embodiments of the application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0188] The above only describes the preferred embodiments of the application and is not intended to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. An adaptive filtering method for GPS circuits, characterized in that, The method includes: Acquire the first radio frequency signal received by the GPS antenna; Based on a preset energy peak detection algorithm, the interference energy distribution spectrum is obtained according to the first radio frequency signal; Obtain the first frequency point and obtain the interference threshold corresponding to the first frequency point; Based on the interference energy distribution spectrum, determine the interference energy at the first frequency point; If the interference energy exceeds the interference threshold, it is marked as an interference frequency point; Based on the interference frequency points, a preset interference library is matched; If it is the first interference frequency, then the corresponding fixed bandstop unit is activated; If it is the second interference frequency, the LC parameters are dynamically calculated based on the interference frequency to configure 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 the preset index threshold, the LC parameter update mechanism is triggered.

2. The adaptive filtering method for GPS circuits according to claim 1, characterized in that, The preset energy peak detection algorithm, based on the first radio frequency signal, obtains the interference energy distribution spectrum, specifically including: In response to a preset first band-stop filter, a first interference signal is obtained based on 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. Based on the first interference signal, the root mean square value of the signal energy in each sub-channel is calculated to obtain the interference energy; The interference energy distribution spectrum is formed based on the first frequency point and the interference energy.

3. The adaptive filtering method for GPS circuits according to claim 1, characterized in that, The step of matching a preset interference library based on the interference frequency point specifically involves: Based on the interference library, the first characteristic frequency point and the second characteristic frequency point are obtained; Determine whether the interference frequency point is the first characteristic frequency point; If so, then the interference frequency point is determined to be the first interference frequency point; If not, then the interference frequency point is determined to be the second interference frequency point; If the interference frequency point is the second characteristic frequency point, then the characteristic LC parameter is output.

4. The adaptive filtering method for GPS circuits according to claim 1, characterized in that, If the frequency is the first interference frequency, the corresponding fixed bandstop unit is activated, specifically: If the first interference frequency point corresponds to a preset first harmonic interference, then the first series resonant circuit is turned on. If the first interference frequency point corresponds to a preset second harmonic interference, then the first parallel resonant network is activated; Based on the first interference frequency point, the auxiliary frequency band is obtained; Activate the corresponding notch filter according to the auxiliary frequency band.

5. The adaptive filtering method for GPS circuits according to claim 1, characterized in that, The step of dynamically calculating LC parameters based on the interference frequency point to configure the programmable resonant unit specifically includes: Based on the interference frequency and the interference energy, the band-stop frequency range and the target suppression depth are obtained; Based on the band-stop frequency range, a preset initial combination of LC values ​​is selected, and the LC values ​​are iteratively optimized using the gradient descent method until the target suppression depth is met, thus obtaining the LC parameters. The C parameter of the LC parameter is written into the register of the numerically controlled capacitor array; The switching code of the inductor matrix is ​​set according to the L parameter of the LC parameter.

6. The adaptive filtering method for GPS circuits according to claim 1, characterized in that, The mechanism for triggering LC parameter updates specifically includes: Detect and obtain the unsuppressed residual interference frequency points and their residual interference energy; The frequency offset is obtained based on the residual interference frequency and the LC parameters; If the frequency offset exceeds the preset offset threshold, the LC value will be iterated and optimized again. If the residual interference energy exceeds the preset energy threshold, the number of capacitor array stages is increased.

7. An adaptive filtering system for GPS circuits, characterized in that, The system includes a memory and a processor. The memory includes an adaptive filtering method program for GPS circuits. When executed by the processor, the adaptive filtering method program for GPS circuits performs the following steps: Acquire the first radio frequency signal received by the GPS antenna; Based on a preset energy peak detection algorithm, the interference energy distribution spectrum is obtained according to the first radio frequency signal; Obtain the first frequency point and obtain the interference threshold corresponding to the first frequency point; Based on the interference energy distribution spectrum, determine the interference energy at the first frequency point; If the interference energy exceeds the interference threshold, it is marked as an interference frequency point; Based on the interference frequency points, a preset interference library is matched; If it is the first interference frequency, then the corresponding fixed bandstop unit is activated; If it is the second interference frequency, the LC parameters are dynamically calculated based on the interference frequency to configure 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 the preset index threshold, the LC parameter update mechanism is triggered.

8. An adaptive filtering system for a GPS circuit according to claim 7, characterized in that, The preset energy peak detection algorithm, based on the first radio frequency signal, obtains the interference energy distribution spectrum, specifically including: In response to a preset first band-stop filter, a first interference signal is obtained based on 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. Based on the first interference signal, the root mean square value of the signal energy in each sub-channel is calculated to obtain the interference energy; The interference energy distribution spectrum is formed based on the first frequency point and the interference energy.

9. An adaptive filtering system for a GPS circuit according to claim 7, characterized in that, The step of matching a preset interference library based on the interference frequency point specifically involves: Based on the interference library, the first characteristic frequency point and the second characteristic frequency point are obtained; Determine whether the interference frequency point is the first characteristic frequency point; If so, then the interference frequency point is determined to be the first interference frequency point; If not, then the interference frequency point is determined to be the second interference frequency point; If the interference frequency point is the second characteristic frequency point, then 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, which, when executed by a processor, implements the steps of the adaptive filtering method for a GPS circuit as described in any one of claims 1 to 6.

Images