A Beidou and GPS integrated anti-interference digital filtering method and its filter

Abstract

The present invention belongs to the technical field of navigation anti-interference, and particularly relates to a Beidou and GPS common trap integrated anti-interference digital filtering method and its filter, including steps of generating the parameters of the first band-pass FIR filter corresponding to the Beidou B1 signal, generating the parameters of the second band-pass FIR filter corresponding to the GPS L1 signal, performing weighted processing on the parameters of the Beidou B1 band-pass FIR filter and the GPS L1 band-pass FIR filter respectively, etc. The present invention generates a composite filter parameter by weighted superposition of two independent band-pass FIR filter parameters, which can simultaneously meet the band-pass requirements of the Beidou B1 signal and the GPS L1 signal, and form a notch in the intermediate frequency band, and then can be effectively integrated into a single FIR structure, with high efficiency, anti-interference performance and hardware friendliness, and further realizes the functions of traditional multi-modules, the resource efficiency is increased by more than 50%, and the effect of supporting dynamic power adaptation is achieved, which is applicable to the high-precision anti-interference processing of multi-mode satellite navigation receivers.

Description

Technical Field

[0001] The present invention belongs to the technical field of navigation anti-interference, and particularly relates to a BeiDou and GPS common-notch integrated anti-interference digital filtering method and its filter. Background Art

[0002] With the full networking of the BeiDou satellite navigation system and its compatible application with the GPS system, the anti-interference ability of dual-mode navigation terminals faces higher requirements in complex electromagnetic environments. The BeiDou system has significant advantages in terms of functional diversity (such as short message communication and high-precision positioning). However, due to the frequency band differences between its signals and GPS signals (BeiDou B1: 1561.098 MHz ± 2 MHz, GPS L1: 1575.42 MHz ± 2 MHz) and the requirements for mixed signal processing, the following prominent problems exist in traditional anti-interference technologies:

[0003] Traditional solutions adopt a dual-independent filter architecture (as shown in Figure 3 ), and band-pass filters need to be designed separately for BeiDou B1 and GPS L1 signals (for example, the passband of the BeiDou B1 filter is 1560 - 1562 MHz, and the passband of the GPS L1 filter is 1574 - 1576 MHz). This design leads to a doubling of the occupancy of hardware resources (such as the DSP unit of the FPGA), and the parallel operation of the two filters has extremely high requirements for real-time performance (for example, a millisecond-level response is required in high-precision positioning scenarios). In addition, the simple superposition of the outputs of the two filters does not consider the signal power differences (such as the GPS signal attenuation being more severe in urban canyons), which may cause weak signals to be submerged by noise and the signal-to-noise ratio to deteriorate significantly. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] Aiming at the problems of high hardware resource occupancy, lack of intermediate frequency band interference suppression, and insufficient dynamic adaptation of signal power caused by the traditional dual-independent filter architecture, the present invention provides a BeiDou and GPS common-notch integrated anti-interference digital filtering method and its filter, which realizes the functions of dual-band signal extraction, out-of-band suppression, and intermediate frequency band notch through a single filter structure, and at the same time supports dynamic adaptation of the signal power ratio, optimizing the signal-to-noise ratio and resource efficiency.

[0006] (II) Technical Solutions

[0007] The present invention is realized through the following technical solutions: The present invention proposes a BeiDou and GPS common-notch integrated anti-interference digital filtering method, including the following steps (the BeiDou B1 signal of the BeiDou positioning system and the L1 signal of the satellite navigation system are hereinafter collectively referred to as the BeiDou B1 signal and the GPS L1 signal):

[0008] Step 1: Generate the first band-pass FIR filter parameters corresponding to the Beidou B1 signal. The passband of the first band-pass FIR filter covers the Beidou B1 signal frequency band, and the stopband covers the frequency bands below the lower limit and above the upper limit of the Beidou B1 signal. The first band-pass FIR filter parameters usually include the passband range and the stopband range, and the parameter design can be carried out with the help of the fdatool tool in MATLAB according to the sampling rate Fs, the cut-off frequencies Fstop1 / Fstop2, and the passband insertion loss Apass. MATLAB (Matrix Laboratory) is a high-performance language for technical computing, including matrix calculations, function and data plotting, algorithm implementation, user interface creation, and interfaces with other programming languages. fdatool is a graphical user interface (GUI) tool in MATLAB for designing, analyzing, and visualizing digital filters. Fs represents the sampling rate, that is, the number of samples collected per second. Fstop1 and Fstop2 represent the start frequency and end frequency of the stopband of the filter (or called the stopband edge frequencies) respectively.

[0009] Step 2: Generate the second band-pass FIR filter parameters corresponding to the GPS L1 signal. The passband of the second band-pass FIR filter covers the GPS L1 signal frequency band, and the stopband covers the frequency bands below the lower limit and above the upper limit of the GPS L1 signal. The second band-pass FIR filter parameters usually also include the passband range and the stopband range, and the same parameter design can also be carried out with the same tools and methods as in Step 1.

[0010] Step 3: Perform weighted processing on the Beidou B1 band-pass FIR filter parameters and the GPS L1 band-pass FIR filter parameters respectively (the weighted processing here is: the product of the Beidou B1 band-pass FIR filter parameters and K B to get the product result, and the product of the GPS L1 band-pass FIR filter parameters and K G to get the product result). Among them, the weighting coefficient of the Beidou B1 band-pass FIR filter parameters is K B , and the weighting coefficient of the GPS L1 band-pass FIR filter parameters is K G , and the following constraint conditions need to be satisfied simultaneously:

[0011] Normalization constraint: K B + K G = 1, power ratio constraint: K B ÷ K G = P B ÷ P G , where P B and P GThey are the power values of the Beidou B1 signal and the GPS L1 signal respectively; the power values of the Beidou B1 signal and the GPS L1 signal may vary in each system. Usually, they can be obtained by measuring the signals in the channel with a spectrum analyzer. In most cases, it can be considered that K1 = K2 = 0.5;

[0012] Step 4: Superimpose the weighted first band-pass FIR filter parameters and the second band-pass FIR filter parameters according to their positions (that is, add the two product results in Step 3) to generate composite filter parameters;

[0013] Step 5: Based on the composite filter parameters, construct a band-pass and notch digital filter (the digital shaping filter uses the composite filter parameters to construct a band-pass and notch digital filter) to achieve the following functions:

[0014] Simultaneously pass through the Beidou B1 signal frequency band and the GPS L1 signal frequency band;

[0015] Suppress the frequency bands below the lower limit of the Beidou B1 signal and above the upper limit of the GPS L1 signal;

[0016] Notch the intermediate frequency band between the Beidou B1 signal and the GPS L1 signal.

[0017] Preferably, the stopband attenuation values of the first band-pass FIR filter and the second band-pass FIR filter are not less than 30 dB.

[0018] Preferably, the intermediate frequency band is the non-overlapping frequency band between the Beidou B1 signal and the GPS L1 signal.

[0019] Preferably, the band-pass and notch digital filter is of FIR structure, and its order is dynamically adjusted according to the stopband attenuation requirements.

[0020] The present invention also provides a band-pass and notch digital filter for implementing the filtering method described in any one of the above, including:

[0021] A Beidou B1 band-pass FIR filter parameter generator for generating the first band-pass FIR filter parameters corresponding to the Beidou B1 signal. The passband of the Beidou B1 band-pass FIR filter parameter generator covers the Beidou B1 signal frequency band, and the stopband covers the frequency bands below the lower limit of the Beidou B1 signal and above its upper limit;

[0022] A GPS L1 band-pass FIR filter parameter generator for generating the second band-pass FIR filter parameters corresponding to the GPS L1 signal. The passband of the GPS L1 band-pass FIR filter parameter generator covers the GPS L1 signal frequency band, and the stopband covers the frequency bands below the lower limit of the GPS L1 signal and above its upper limit;

[0023] Multipliers, two in number, are used to perform weighted processing on the Beidou B1 band-pass FIR filter parameters and the GPS L1 band-pass FIR filter parameters respectively. Among them, the weighting coefficient of the Beidou B1 band-pass FIR filter parameters is K B , and the weighting coefficient of the GPS L1 band-pass FIR filter parameters is K G , and the following constraint conditions need to be satisfied simultaneously:

[0024] Normalization constraint: K B +K G = 1, Power ratio constraint: K B ÷K G = P B ÷P G , where P B 、P G are the power values of the Beidou B1 signal and the GPS L1 signal respectively;

[0025] A vector adder is used to superimpose the weighted first band-pass FIR filter parameters and the second band-pass FIR filter parameters by position to generate composite filter parameters;

[0026] A digital filter shaper is used to construct a band-stop integrated digital filter according to the composite filter parameters. The band-stop integrated digital filter realizes the following functions:

[0027] Simultaneously pass through the Beidou B1 signal frequency band and the GPS L1 signal frequency band;

[0028] Suppress the frequency bands below the lower limit of the Beidou B1 signal and above the upper limit of the GPS L1 signal;

[0029] Notch the intermediate frequency band between the Beidou B1 signal and the GPS L1 signal.

[0030] Preferably, the filtering execution module is an FPGA or ASIC hardware logic unit.

[0031] (III) Beneficial effects

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] By weighted superposition of the parameters of two independent band-pass FIR filters, the present invention generates a composite filter parameter, which can simultaneously meet the band-pass requirements of the Beidou B1 signal and the GPS L1 signal, and form a notch in the intermediate frequency band. Furthermore, it can be effectively integrated into a single FIR structure, with high efficiency, anti-interference ability and hardware friendliness. Moreover, it realizes the functions of traditional multi-modules, the resource efficiency is increased by more than 50%, and it supports the effect of dynamic power adaptation, and is applicable to the high-precision anti-interference processing of multi-mode satellite navigation receivers. Description of the drawings

[0034] Other features, objectives, and advantages of the present invention will become more apparent by reading the following detailed description of non - restrictive embodiments with reference to the accompanying drawings:

[0035] Figure 1 It is a flowchart of the filtering method of the present invention.

[0036] Figure 2 It is a functional structure diagram of the filter of the present invention.

[0037] Figure 3 It is a diagram of a traditional dual - independent filter architecture.

[0038] Figure 4 It is a diagram of the filter architecture of the present invention.

[0039] Figure 5 It is a simulation diagram of the all - in - one band - pass and band - stop digital filter constituted in the embodiment of the present invention. Specific Embodiments

[0040] In this technical solution:

[0041] In order to make the objectives, technical solutions, and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] Refer to Figure 1 As shown, the present invention proposes an all - in - one band - pass and band - stop anti - interference digital filtering method for Beidou and GPS, including the following steps (the Beidou positioning system B1 signal and the satellite navigation system L1 signal are hereinafter collectively referred to as the Beidou B1 signal and the GPS L1 signal):

[0043] Step 1: Generate the first band - pass FIR filter parameters corresponding to the Beidou B1 signal. The pass - band of the first band - pass FIR filter covers the Beidou B1 signal frequency band, and the stop - band covers the frequency bands below the lower limit and above the upper limit of the Beidou B1 signal. The first band - pass FIR filter parameters usually include the pass - band range and the stop - band range, and can be designed according to the sampling rate Fs, the cut - off frequencies Fstop1 / Fstop2, and the pass - band insertion loss Apass with the help of the fdatool tool in MATLAB. MATLAB (Matrix Laboratory) is a high - performance language for technical computing, including matrix calculations, function and data plotting, algorithm implementation, user interface creation, and interfaces with other programming languages. fdatool is a graphical user interface (GUI) tool in MATLAB for designing, analyzing, and visualizing digital filters. Fs represents the sampling rate, that is, the number of samples collected per second. Fstop1 and Fstop2 represent the start frequency and end frequency of the stop - band of the filter (or called the stop - band edge frequencies) respectively.

[0044] Step 2: Generate the second band - pass FIR filter parameters corresponding to the GPS L1 signal. The pass - band of the second band - pass FIR filter covers the GPS L1 signal frequency band, and the stop - band covers the frequency bands below the lower limit and above the upper limit of the GPS L1 signal. The second band - pass FIR filter parameters usually also include the pass - band range and the stop - band range, and can also be designed with the same parameters using the same tools and methods as in Step 1.

[0045] Step 3: Perform weighted processing on the Beidou B1 band - pass FIR filter parameters and the GPS L1 band - pass FIR filter parameters respectively (the weighted processing here is: the product of the Beidou B1 band - pass FIR filter parameters and K B to get the product result, and the product of the GPS L1 band - pass FIR filter parameters and K G to get the product result). Among them, the weighting coefficient of the Beidou B1 band - pass FIR filter parameters is K B and the weighting coefficient of the GPS L1 band - pass FIR filter parameters is K G , and the following constraint conditions need to be satisfied simultaneously:

[0046] Normalization constraint: K B +K G = 1, Power ratio constraint: K B ÷K G = P B ÷P G where P B 、P GThey are the power values of the Beidou B1 signal and the GPS L1 signal respectively; the power values of the Beidou B1 signal and the GPS L1 signal may vary in each system. Usually, they can be obtained by measuring the signals in the channel with a spectrum analyzer. In most cases, it can be considered that K1 = K2 = 0.5;

[0047] Step 4: Superimpose the weighted first band-pass FIR filter parameters and the second band-pass FIR filter parameters by position (that is, add the two product results in Step 3) to generate composite filter parameters;

[0048] Step 5: Based on the composite filter parameters, construct a band-pass and notch digital filter (the digital shaping filter uses the composite filter parameters to construct a band-pass and notch digital filter) to achieve the following functions:

[0049] Simultaneously pass through the Beidou B1 signal frequency band and the GPS L1 signal frequency band (that is, input signal (Beidou B1 signal + GPS L1 signal + interference signal) → ADC sampling → band-pass and notch filter → output signal (pure Beidou B1 + GPS L1, suppressing out-of-band and intermediate frequency bands), as Figure 4 shown);

[0050] Suppress the frequency bands below the lower limit of the Beidou B1 signal and above the upper limit of the GPS L1 signal;

[0051] Notch the intermediate frequency band between the Beidou B1 signal and the GPS L1 signal.

[0052] Among them, the stopband attenuation values of the first band-pass FIR filter and the second band-pass FIR filter are not less than 30 dB.

[0053] Among them, the intermediate frequency band is the non-overlapping frequency band between the Beidou B1 signal and the GPS L1 signal.

[0054] Among them, the band-pass and notch digital filter is of FIR structure, and its order is dynamically adjusted according to the stopband attenuation requirement.

[0055] As Figure 2 shown, the present invention also provides a band-pass and notch digital filter for implementing the filtering method described in any one of the above, including:

[0056] A Beidou B1 band-pass FIR filter parameter generator for generating the first band-pass FIR filter parameters corresponding to the Beidou B1 signal. The passband of the Beidou B1 band-pass FIR filter parameter generator covers the Beidou B1 signal frequency band, and the stopband covers the frequency bands below the lower limit of the Beidou B1 signal and above its upper limit;

[0057] A GPS L1 band-pass FIR filter parameter generator is used to generate the second band-pass FIR filter parameters corresponding to the GPS L1 signal. The passband of the GPS L1 band-pass FIR filter generator covers the GPS L1 signal frequency band, and the stopband covers the frequency bands below the lower limit and above the upper limit of the GPS L1 signal.

[0058] There are two multipliers, which are used to perform weighted processing on the Beidou B1 band-pass FIR filter parameters and the GPS L1 band-pass FIR filter parameters respectively. Among them, the weighting coefficient of the Beidou B1 band-pass FIR filter parameters is K B , and the weighting coefficient of the GPS L1 band-pass FIR filter parameters is K G , and the following constraint conditions need to be satisfied simultaneously:

[0059] Normalization constraint: K B +K G =1, power ratio constraint: K B ÷K G = P B ÷P G , where P B 、P G are the power values of the Beidou B1 signal and the GPS L1 signal respectively;

[0060] A vector adder is used to superimpose the weighted first band-pass FIR filter parameters and the second band-pass FIR filter parameters by position to generate composite filter parameters;

[0061] A digital filter shaper is used to construct a band-pass and notch integrated digital filter according to the composite filter parameters. The band-pass and notch integrated digital filter realizes the following functions:

[0062] Simultaneously pass through the Beidou B1 signal frequency band and the GPS L1 signal frequency band;

[0063] Suppress the frequency bands below the lower limit of the Beidou B1 signal and above the upper limit of the GPS L1 signal;

[0064] Notch the intermediate frequency band between the Beidou B1 signal and the GPS L1 signal.

[0065] Among them, the filtering execution module is an FPGA or ASIC hardware logic unit.

[0066] The present invention generates a synthetic filter parameter by weighted superposition of two independent band - pass FIR filter parameters. This parameter can simultaneously meet the band - pass requirements of Beidou B1 signal and GPS L1 signal, form a notch in the intermediate frequency band, and can thus be effectively integrated into a single FIR structure, with high efficiency, anti - interference ability, and hardware - friendliness. Furthermore, it can achieve traditional multi - module functions, with a resource efficiency improvement of more than 50%, and support the effect of dynamic power adaptation, being applicable to high - precision anti - interference processing of multi - mode satellite navigation receivers.

[0067] The following are the detailed implementation steps and feature descriptions:

[0068] Generation of sub - filter parameters:

[0069] Generation of band - pass FIR filter parameters for Beidou B1 signal:

[0070] Design a band - pass filter whose pass - band covers the Beidou B1 frequency band (e.g., 1561.098 ± 2.046 MHz);

[0071] Design the stop - band in the frequency band outside the upper and lower limits of the pass - band to ensure that the stop - band attenuation is at least 30 dB;

[0072] Generation of band - pass FIR filter parameters for GPS L1 signal:

[0073] Design a band - pass filter whose pass - band covers the GPS L1 frequency band (e.g., 1575.42 ± 1.023 MHz);

[0074] The stop - band design also follows the principle of ensuring sufficient attenuation;

[0075] Tool support:

[0076] Use the fdatool tool in MATLAB to automatically generate the parameters of the FIR filter according to the given sampling rate Fs, cut - off frequencies Fstop1 / Fstop2, and pass - band insertion loss Apass;

[0077] Weighting process (meeting the following two conditions simultaneously):

[0078] Normalization constraint (K B +K G = 1), ensuring the stability of the synthetic filter gain and avoiding amplitude distortion;

[0079] Power ratio constraint (K B ÷K G = P B ÷P G ), adjusting the weighting coefficient according to the actual signal power (e.g., a weaker Beidou signal requires a higher gain) to ensure the balance of the output signal power;

[0080] Parameter superposition and synthesis filter construction:

[0081] Add the weighted coefficients of the two filters point by point to generate synthesis coefficients;

[0082] Frequency response superposition effect:

[0083] Passband retention: The passbands of Beidou B1 and GPS L1 are retained due to coefficient superposition.

[0084] Notch formation: In the intermediate frequency band (such as from the upper limit of Beidou B1 to the lower limit of GPS L1), a high attenuation region (notch) is formed due to the superposition of the stopbands of the two filters;

[0085] Out-of-band suppression: The frequency bands below Beidou B1 and above GPS L1 are suppressed by the combined stopband;

[0086] Hardware implementation:

[0087] FPGA / ASIC implementation: Load the synthesis coefficients into a digital filter shaper (such as a FIR convolution engine) to perform real-time filtering on the mixed signal after ADC sampling;

[0088] Dynamic adjustment: By updating the coefficient table, it can be dynamically adapted to different frequency band requirements or interference environments;

[0089] As can be seen from the above, the present invention has the following positive effects:

[0090] Efficient design of integrated passband and notch

[0091] Function integration: By using a single filter, passband filtering (retaining Beidou B1 and GPS L1 signals) and notch (suppressing intermediate frequency band interference) are simultaneously achieved, avoiding the complexity of traditional multi-stage cascaded filtering and reducing hardware resource consumption;

[0092] Dynamic adaptation: The filter order can be dynamically adjusted according to the stopband attenuation requirement to flexibly cope with the interference intensity in different environments;

[0093] Outstanding anti-interference ability

[0094] High stopband attenuation: The stopband attenuation of both sub-filters is not less than 30 dB, effectively suppressing out-of-band noise and adjacent frequency band interference;

[0095] Accurate notch: Actively suppress the non-overlapping intermediate frequency band between Beidou B1 and GPS L1 to reduce signal crosstalk;

[0096] Power ratio self-adaptation

[0097] Weighted optimization, that is, through normalization constraint and power ratio constraint, ensure that the synthesis filter parameters match the signal power, avoiding signal distortion or power imbalance;

[0098] Strong environmental adaptability: It supports dynamically measuring power values through a spectrum analyzer and adapting to signal strength changes in different scenarios (such as urban multipath, electromagnetic interference, etc.);

[0099] Efficient hardware implementation

[0100] Modular design: The parameter generation, weighting, superposition, and filtering shaping modules are discrete, facilitating the implementation of FPGA or ASIC hardware logic and meeting the requirements of real-time processing;

[0101] Resource reuse: The filter parameters of Beidou B1 and GPS L1 can reuse the same design tools (such as MATLAB fdatool), reducing development costs;

[0102] Compatibility and scalability

[0103] Support for multiple systems: It can be extended to other satellite navigation frequency bands (such as GLONASS, Galileo), and only the filter parameters need to be adjusted;

[0104] Mature software toolchain: The filter design process based on MATLAB is standardized, shortening the development cycle.

[0105] Example: Filter synthesis based on a fixed power ratio (K B =K G =0.5)

[0106] Parameter configuration and implementation steps

[0107] Generation of Beidou B1 signal bandpass FIR filter parameters:

[0108] Tool: MATLAB fdatool;

[0109] Parameter settings:

[0110] Sampling rate Fs = 200MHz;

[0111] Stopband frequency: The low-frequency cut-off frequency Fstop1 is 35.098MHz, and the high-frequency cut-off frequency Fstop2 is 43.098MHz;

[0112] Passband frequency: The low-frequency pass frequency Fpass1 is 37.098MHz, and the high-frequency pass frequency Fpass2 is 41.098MHz;

[0113] Stopband attenuation: Astop1 = Astop2 = 30dB;

[0114] Passband insertion loss: Apass is 1dB;

[0115] Generate Beidou B1 signal bandpass FIR filter parameters (partial example)

[0116] Fir1_num1 = -0.00320358466750386;

[0117] Fir1_num2 = -0.0212100617063406;

[0118] … …

[0119] Fir1_num201 = -0.00320358466750386;

[0120] GPS L1 signal band - pass FIR filter parameter generation:

[0121] Tool: MATLAB fdatool;

[0122] Parameter settings:

[0123] Sampling rate Fs = 200MHz;

[0124] Stop - band frequency: low - frequency cut - off frequency Fstop1 is 49.42MHz, high - frequency cut - off frequency Fstop2 is 57.42MHz;

[0125] Pass - band frequency: low - frequency pass - through frequency Fpass1 is 51.42MHz, high - frequency pass - through frequency Fpass2 is 55.42MHz;

[0126] Stop - band attenuation: Astop1 = Astop2 = 30dB;

[0127] Pass - band insertion loss: Apass is 1dB;

[0128] Generate GPS L1 signal band - pass FIR filter parameters (partial examples)

[0129] Fir2_num1 = -0.000266055525037489;

[0130] Fir2_num2 = -0.00145016021200931;

[0131] … …

[0132] Fir2_num201 = -0.000266055525037489;

[0133] Parameter weighting process (K B = K G = 0.5):

[0134] BeiDou B1 signal band - pass FIR filter parameter weighting (partial examples):

[0135] Fir1_factor1 = Fir1_num1 × 0.5 = -0.00160179233375193;

[0136] Fir1_factor2 = Fir1_num2 × 0.5 = -0.0106050308531703; ... ;

[0138] GPS L1 signal band - pass FIR filter parameter weighting (partial example);

[0139] Fir2_factor1 = Fir2_num1 × 0.5 = -0.000133027762518745;

[0140] Fir2_factor2 = Fir2_num2 × 0.5 = -0.000725080106004655; ... ;

[0142] Parameter synthesis

[0143] Fir_data1=Fir1_factor1+Fir2_factor1=-0.00160179233375193+(-0.000133027762518745)=-0.00173482009627068;

[0144] Fir_data2=Fir1_factor2+Fir2_factor2=-0.0106050308531703+(-0.000725080106004655)=-0.0113301109591749; ...;

[0146] Fir_data201=Fir1_num201×0.5+Fir2_num201×0.5=0.00320358466750386×0.5+(0.000266055525037489)×0.5=0.00173482009627068;

[0147] Finally, the digital shaping filter uses the parameters (Fir_data1, Fir_data2,..., Fir_data201) generated by the vector adder to design a digital filter with both pass - band and stop - band characteristics, thus completing the filtering method.

[0148] Verify the performance of the digital filter with both pass - band and stop - band characteristics in the embodiment. Starting from Figure 5From the simulation diagram of the pass-and-trap integrated digital filter, it can be seen that the filter realizes the function of simultaneously passing the Beidou B1 signal of 39.098±2MHz and the GPS L1 signal of 53.42±2MHz, and realizes the stopband suppression capability below 35.098MHz and above 57.42MHz, and realizes the notch function of the signal between 45MHz and 50MHz. Compared with the traditional method, only one digital filter is needed to realize it, that is, the dual filter (450 order) is compressed into a single filter (201 order) through parameter synthesis, saving more than 50% of logic resources. In addition, dynamic parameter adaptation, that is, K can be adjusted in real time according to the signal power. B With K G ,Adapt to complex electromagnetic environment, and,enhance anti-interference: the synthesized intermediate notch depth is ≥30dB, which is better than the traditional combiner solution.

[0149] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices stated in the device claim can also be implemented by one unit or device through software or hardware. The words first, second, etc. are used to indicate names, and do not indicate any particular order.

[0150] Finally, it should be noted that the above is only a specific example of the present invention. Obviously, the present invention is not limited to the above example, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A Beidou and GPS integrated anti-interference digital filtering method for communication and positioning, characterized in that: Including the following steps: Step 1: Generate the first band-pass FIR filter parameters corresponding to the Beidou B1 signal; Step 2: Generate the second band-pass FIR filter parameters corresponding to the GPS L1 signal; Step 3: Perform weighted processing on the Beidou B1 band-pass FIR filter parameters and the GPS L1 band-pass FIR filter parameters respectively, where the weighting coefficient of the Beidou B1 band-pass FIR filter parameters is K B , and the weighting coefficient of the GPS L1 band-pass FIR filter parameters is K G , and the following constraint conditions need to be satisfied simultaneously: Normalization constraint: K B + K G = 1, power ratio constraint: K B ÷ K G = P B ÷ P G , where P B 、P G are the power values of the Beidou B1 signal and the GPS L1 signal respectively; Step 4: Superimpose the weighted first band-pass FIR filter parameters and the second band-pass FIR filter parameters by position to generate composite filter parameters; Step 5: Construct a band-pass and notch digital filter based on the composite filter parameters, and the band-pass and notch digital filter realizes the following functions: Simultaneously pass through the Beidou B1 signal frequency band and the GPS L1 signal frequency band; Suppress the frequency bands below the lower limit of the Beidou B1 signal and above the upper limit of the GPS L1 signal; Notch the intermediate frequency band between the Beidou B1 signal and the GPS L1 signal.

2. A Beidou and GPS integrated anti-interference digital filtering method according to claim 1, characterized in that: The stopband attenuation value of the first band-pass FIR filter and the second band-pass FIR filter is not less than 30 dB.

3. A Beidou and GPS integrated anti-interference digital filtering method according to claim 1, characterized in that: The intermediate frequency band is the non-overlapping frequency band between the Beidou B1 signal and the GPS L1 signal.

4. A Beidou and GPS integrated anti-interference digital filtering method according to claim 1, characterized in that: The band-pass and notch digital filter is of FIR structure, and its order is dynamically adjusted according to the stopband attenuation requirement.

5. A combined notch and low-pass digital filter is used to implement a Beidou and GPS combined notch and anti-interference digital filtering method according to any one of claims 1-4, and is characterized in that: Including: A Beidou B1 band-pass FIR filter parameter generator for generating the first band-pass FIR filter parameters corresponding to the Beidou B1 signal. The passband of the Beidou B1 band-pass FIR filter parameter generator covers the Beidou B1 signal frequency band, and the stopband covers the frequency bands below the lower limit of the Beidou B1 signal and above its upper limit; A GPS L1 band-pass FIR filter parameter generator for generating the second band-pass FIR filter parameters corresponding to the GPS L1 signal. The passband of the GPS L1 band-pass FIR filter parameter generator covers the GPS L1 signal frequency band, and the stopband covers the frequency bands below the lower limit of the GPS L1 signal and above its upper limit; Multipliers, there are two of them, used to perform weighted processing on the Beidou B1 band-pass FIR filter parameters and the GPS L1 band-pass FIR filter parameters respectively. Among them, the weighting coefficient of the Beidou B1 band-pass FIR filter parameters is K B , and the weighting coefficient of the GPS L1 band-pass FIR filter parameters is K G , and the following constraint conditions need to be satisfied simultaneously: Normalization constraint: K B + K G = 1, power ratio constraint: K B ÷ K G = P B ÷ P G , where P B and P G are the power values of the Beidou B1 signal and the GPS L1 signal respectively; A vector adder for superimposing the weighted first band-pass FIR filter parameters and the second band-pass FIR filter parameters by position to generate composite filter parameters; A digital filter shaper for constructing a band-pass and notch digital filter according to the composite filter parameters, and the band-pass and notch digital filter realizes the following functions: Simultaneously pass through the Beidou B1 signal frequency band and the GPS L1 signal frequency band; Suppress the frequency bands below the lower limit of the Beidou B1 signal and above the upper limit of the GPS L1 signal; Notch the intermediate frequency band between the Beidou B1 signal and the GPS L1 signal.

6. The integrated digital filter for both passing and trapping according to claim 5, characterized in that, The filtering execution module is an FPGA or ASIC hardware logic unit.

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