Satellite navigation narrowband anti-jamming device, method and receiver for small resources

Abstract

The application relates to a small-resource satellite navigation narrow-band anti-interference device, method and receiver, and belongs to the technical field of satellite navigation. The device comprises a preprocessing module which is used for carrying out window processing on N-point data taken from a satellite navigation AD signal as a first-path signal and a satellite navigation AD signal after delaying N / 2 points as a second-path signal respectively; adding N / 2 zeros to the back of the first-path signal and the front of the second-path signal after the window processing respectively, and carrying out data merging to obtain a synthesized signal with a length of 1.5N points; an interference identification and removal module which is used for converting the synthesized signal into a frequency domain, carrying out interference identification and removal in each frequency domain point respectively, and obtaining a frequency domain signal after interference removal; and a signal extraction module which is used for converting the frequency domain signal output by the interference identification and removal module into a time domain signal, extracting an effective signal with a length of N / 2 points from N / 2 points to N points in the time domain signal, and outputting the effective signal. The application reduces the calculation amount, occupies less resources, and is low in power consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of satellite navigation technology, in particular to a satellite navigation narrow-band anti-interference device, method and receiver with small resources. BACKGROUND

[0002] Satellite navigation positioning has the characteristics of global coverage, all-weather, high precision, etc., and is widely used in weapons, transportation, precision agriculture, marine fisheries, finance and power, mobile phone terminals and other fields. However, in practical application, satellite navigation receivers face various kinds of interference, one of which is narrow-band interference. Narrow-band interference refers to interference with a spectrum occupying less than or equal to 10% of the total bandwidth, which is usually emitted by an electromagnetic source and has a long duration, directly affecting the normal operation of the receiver. The anti-narrow-band interference capability of a satellite navigation receiver is an important capability index of the satellite navigation receiver.

[0003] Anti-narrow-band interference is divided into time domain filtering and frequency domain filtering. Time domain algorithms are generally more complex and are suitable for suppressing slow-changing interference, but have slightly poor adaptability to the environment. Spatial domain algorithms have good anti-interference effect, but due to the limitation of hardware cost, they require high investment. Relatively speaking, frequency domain anti-interference technology is relatively simple to implement, and has good suppression effect on single-frequency interference and partial-band interference, so it has a wide range of applications. Traditional satellite navigation receivers use a double-window frequency domain method to resist narrow-band interference. In the double-window frequency domain method, a segment of N / 2-point signal is processed, which requires the calculation of two groups of N-point FFT and two groups of N-point inverse FFT, resulting in a large amount of calculation and high resource consumption. SUMMARY

[0004] In view of the above analysis, the present application aims to disclose a satellite navigation narrow-band anti-interference device, method and receiver with small resources, which solves the problem of large amount of calculation and high resource consumption in the traditional double-window frequency domain method.

[0005] In one aspect, the present application discloses a satellite navigation narrow-band anti-interference device with small resources, comprising:

[0006] A preprocessing module is configured to take out N-point data from a satellite navigation AD signal as a first signal and a satellite navigation AD signal after delaying N / 2 points as a second signal for windowing processing; and add N / 2 zeros to the back of the first signal and the front of the second signal after windowing processing, and then perform data merging to obtain a synthesized signal with a length of 1.5N points.

[0007] An interference identification and removal module is configured to convert the synthesized signal into the frequency domain, and perform interference identification and removal in each frequency domain point to obtain a frequency domain signal after interference removal.

[0008] The signal extraction module is configured to convert the frequency domain signal output by the interference identification removal module into a time domain signal, and extract an effective signal with a length of N / 2 points from N / 2 points to N points in the time domain signal and output the effective signal; the effective signal is a signal of the second channel signal before N / 2 points.

[0009] Further, the preprocessing module comprises a first group of data buffer modules, a windowing module, a second group of data buffer modules, a zero padding module, a third group of data buffer modules, a summation module and a fourth group of data buffer modules.

[0010] The first group of data buffer modules comprises two N-point data buffer areas, wherein a first N-point data buffer area is configured to buffer an N-point first channel signal, and a second N-point data buffer area is configured to buffer an N-point second channel signal.

[0011] The windowing module is configured to perform windowing processing on the data in the first N-point data buffer area and the second N-point data buffer area, respectively.

[0012] The second group of data buffer modules comprises two N-point data buffer areas, wherein a third N-point data buffer area is configured to buffer the data after the windowing processing on the first N-point data buffer area, and a fourth N-point data buffer area is configured to buffer the data after the windowing processing on the second N-point data buffer area.

[0013] The third group of data buffer modules comprises two 1.5N-point data buffer areas, a first 1.5N-point data buffer area and a second 1.5N-point data buffer area.

[0014] The zero padding module is configured to pad N / 2 zeros at the back of the data in the third N-point data buffer area to form a 1.5N-point data buffer in the first 1.5N-point data buffer area, and pad N / 2 zeros at the front of the data in the fourth N-point data buffer area to form a 1.5N-point data buffer in the second 1.5N-point data buffer area.

[0015] The summation module is configured to add and sum the buffered data in the first 1.5N-point data buffer area and the second 1.5N-point data buffer area.

[0016] The fourth group of data buffer modules comprises a 1.5N-point data buffer area, a third 1.5N-point data buffer area, which is configured to buffer the 1.5N-point summed data output by the summation module as a composite signal.

[0017] Further, the windowing module performs windowing processing by using a Blackman-Harris window.

[0018] Further, the interference identification removal module comprises an FFT module and an anti-interference algorithm module.

[0019] The FFT module is used for performing 1.5N length FFT on the synthesized signal to obtain a frequency domain signal;

[0020] The anti-interference algorithm module is used for comparing the amplitude of each frequency point of the frequency domain signal with a set interference judgment threshold value, identifying narrowband interference, determining the interfered frequency points and removing the interference signal in the frequency points.

[0021] Further, the algorithm executed in the anti-interference algorithm module comprises:

[0022] 1) determining the interference judgment threshold value according to the input spectrum X(k);

[0023] 2) setting k to zero and j to zero;

[0024] 3) judging whether j>0.15N is true; if not, entering the next step; if yes, the interference bandwidth is too wide, the data is unusable, and the processing process is ended;

[0025] 4) judging whether k<1.5N is true; if yes, entering the next step; if not, outputting the spectrum X_anti(k) after removing the narrowband interference;

[0026] 5) judging whether X(k) is greater than the interference judgment threshold value; if yes, X(k)=0, k=k+1, and j=j+1; if not, X(k) and j remain unchanged, and k=k+1;

[0027] 6) returning to step 3).

[0028] Further, the signal extraction module comprises an IFFT module and an extraction output module.

[0029] The IFFT module is used for performing 1.5N length IFFT on the frequency domain signal after removing the interference to obtain a time domain signal;

[0030] The extraction output module is used for extracting the effective signal with a length of N / 2 points from N / 2 points to N points in the time domain signal to output.

[0031] Another aspect of the present application also discloses a small resource satellite navigation narrowband anti-interference method, comprising:

[0032] Step S1, taking out N point data from a satellite navigation AD signal as a first signal and a satellite navigation AD signal after delaying N / 2 points as a second signal respectively to perform windowing processing; adding N / 2 zeros to the back of the first signal and the front of the second signal after the windowing processing respectively to perform data merging to obtain a synthesized signal with a length of 1.5N points;

[0033] Step S2, converting the synthetic signal into frequency domain, respectively performing interference identification and removal in each frequency domain point, and obtaining the frequency domain signal after interference removal;

[0034] Step S3, converting the frequency domain signal output by the interference identification and removal module into time domain signal, extracting the effective signal of N / 2 points in length from N / 2 points to N points in the time domain signal for output; the effective signal is the signal of the first N / 2 points of the second signal after interference removal;

[0035] N-point signals are sequentially taken from the first and second signals, and the processing of steps S1-S3 is performed to perform narrowband anti-interference on the satellite navigation AD signal sequence.

[0036] Further, in step S1, the Blackman-Harris window is used to perform windowing processing on the N-point satellite navigation AD signal and the satellite navigation AD signal delayed by N / 2 points, respectively.

[0037] Further, in step S2, the interference identification and removal process in each frequency domain point includes:

[0038] 1) determining the interference judgment threshold according to the input spectrum X(k);

[0039] 2) setting k to zero and j to zero;

[0040] 3) judging whether j>0.15N is true; if not, proceeding to the next step; if yes, the interference bandwidth is too wide, the data is unusable, and the processing process is ended;

[0041] 4) judging whether k<1.5N is true; if true, proceeding to the next step; if not, outputting the frequency spectrum X_anti(k) after narrowband interference removal;

[0042] 5) judging whether X(k) is greater than the interference judgment threshold; if yes, X(k)=0, k=k+1, j=j+1; if not, X(k) and j remain unchanged, and k=k+1;

[0043] 6) returning to step 3).

[0044] Another aspect of the present application also discloses a satellite navigation receiver, comprising the small-resource satellite navigation narrowband anti-interference device as described above;

[0045] After the satellite navigation receiver performs AD processing on the received navigation satellite signal, the satellite navigation narrowband anti-interference device is used to remove the narrowband interference signal; and then the AD signal after narrowband interference signal removal is subjected to capture and tracking processing.

[0046] The present application can achieve one of the following beneficial effects:

[0047] The small resource satellite navigation narrowband anti-interference device, method and receiver disclosed by the application can effectively suppress narrowband interference; compared with the traditional double window frequency domain method, the calculation amount is reduced by 25%, the frequency resolution is higher, the interference is more accurate, the damage to the useful signal is smaller, and the application has important engineering value. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments thereof, and together with the description serve to explain the principles of the application.

[0049] Figure 1 The small resource satellite navigation narrowband anti-interference device in the embodiment of the application is connected to a block diagram;

[0050] Figure 2 The pre-processing module in the embodiment of the application is connected to a block diagram;

[0051] Figure 3 The time-frequency characteristic diagram of the window function in the embodiment of the application;

[0052] Figure 4 The algorithm flowchart executed in the anti-interference algorithm module in the embodiment of the application;

[0053] Figure 5 The small resource satellite navigation narrowband anti-interference method flowchart in the embodiment of the application;

[0054] Figure 6-1 The narrowband interference signal spectrum diagram in the embodiment of the application;

[0055] Figure 6-2 The narrowband interference signal capture result diagram in the embodiment of the application;

[0056] Figure 7-1 The spectrum diagram after anti-narrowband interference of scheme 1;

[0057] Figure 7-2 The capture result diagram after anti-narrowband interference of scheme 1;

[0058] Figure 8-1 The spectrum diagram after anti-narrowband interference of scheme 2;

[0059] Figure 8-2 The capture result diagram after anti-narrowband interference of scheme 2. DETAILED DESCRIPTION

[0060] The preferred embodiments of the application will be specifically described below in combination with the accompanying drawings, wherein the drawings constitute a part of this application and are used together with the embodiments of the application to explain the principles of the application.

[0061] Embodiment one

[0062] One embodiment of the present application discloses a small resource satellite navigation narrowband anti-interference device, as shown in the figure, comprising: Figure 1

[0063] a preprocessing module, used for taking out N-point data from a satellite navigation AD signal as a first path signal and a satellite navigation AD signal after delaying N / 2 points as a second path signal respectively for windowing processing; adding N / 2 zeros to the back of the first path signal and the front of the second path signal respectively after the windowing processing to perform data merging, and obtaining a synthesized signal with a length of 1.5N points;

[0064] an interference identification and removal module, used for converting the synthesized signal into a frequency domain, performing interference identification and removal in each frequency domain point respectively, and obtaining a frequency domain signal after interference removal;

[0065] a signal extraction module, used for converting the frequency domain signal output by the interference identification and removal module into a time domain signal, extracting an effective signal with a length of N / 2 points from N / 2 points to N points in the time domain signal for output; the effective signal is a signal of the second path signal before N / 2 points after interference removal.

[0066] The satellite navigation AD signal sequence is subjected to narrowband anti-interference through sequentially taking out, synthesizing, interference identification and removal and extracting of the first path signal and the second path signal.

[0067] As shown in the figure, the preprocessing module comprises a first group of data buffer modules, a windowing module, a second group of data buffer modules, a zero padding module, a third group of data buffer modules, a summation module and a fourth group of data buffer modules. Figure 2

[0068] The first group of data buffer modules comprises two N-point data buffer areas, wherein a first N-point data buffer area is used for buffering N-point first path signals x 1_pre (n), and a second N-point data buffer area is used for buffering N-point second path signals x 2_pre (n); n=1~N;

[0069] The windowing module is used for performing windowing processing on the data in the first N-point data buffer area and the second N-point data buffer area respectively.

[0070] The sidelobe of the rectangular window function is relatively high, so that the signal has relatively large spectrum leakage, and the windowing can effectively improve it; the commonly used window functions include Hamming window, Blackman window, Blackman-Harris window and the like.

[0071] As shown in the figure, it is a time-frequency characteristic diagram of the window function. Figure 3

[0072] ​​​Preferably, the windowing processing is performed by using a Blackman-Harris window, which has lower side lobes and can reduce spectrum leakage;

[0073] The second group of data buffer modules comprises two N-point data buffer areas, wherein a third N-point data buffer area is configured to buffer data x1(n) after windowing processing of the first N-point data buffer area, and a fourth N-point data buffer area is configured to buffer data x2(n) after windowing processing of the second N-point data buffer area;

[0074] x1(n) = x 1_pre (n) x win(n), n = 1 ~ N;

[0075] x2(n) = x 2_pre (n) x win(n), n = 1 ~ N;

[0076] wherein win(n) is a Blackman-Harris window;

[0077] The third group of data buffer modules comprises two 1.5N-point data buffer areas, a first 1.5N-point data buffer area and a second 1.5N-point data buffer area;

[0078] The zero padding module is configured to pad N / 2 zeros at the back of data in the third N-point data buffer area to form 1.5N-point data x 1_0 (n) and buffer the data into the first 1.5N-point data buffer area, and pad N / 2 zeros at the front of data in the fourth N-point data buffer area to form 1.5N-point data x 2_0 (n) and buffer the data into the second 1.5N-point data buffer area; n = 1 ~ 1.5N;

[0079] The summation module is configured to add and sum data buffered in the first 1.5N-point data buffer area and the second 1.5N-point data buffer area;

[0080] The fourth group of data buffer modules comprises a third 1.5N-point data buffer area, which is configured to buffer 1.5N-point summed data x new (n) output by the summation module as a synthetic signal;

[0081] x new (n) = x 1_0 (n) + x 2_0 (n), n = 1 ~ 1.5N.

[0082] Specifically, the interference identification and removal module comprises an FFT module and an anti-interference algorithm module;

[0083] The FFT module is configured to perform 1.5N length FFT on the synthesized signal to obtain a frequency domain signal X(k) = FFT(x new (n)), k = 1 ~ 1.5N;

[0084] The anti-interference algorithm module is configured to compare the amplitude of each frequency point of the frequency domain signal X(k) with a set interference judgment threshold, identify narrowband interference, determine the frequency points interfered, and remove the interference signal in the frequency points.

[0085] If there is no interference, the signal envelope obeys Rayleigh distribution, and the signal envelope probability density function is:

[0086]

[0087] wherein σ is the standard deviation of the signal;

[0088] If there is interference, the signal envelope obeys Rician distribution, and the signal envelope probability density function is:

[0089]

[0090] wherein A is the interference amplitude; I0 is the modified 0th order Bessel function of the first kind;

[0091] If the threshold is a, the false alarm rate is:

[0092]

[0093] The missed alarm rate is:

[0094]

[0095] The interference judgment threshold is set according to the required false alarm rate and missed alarm rate.

[0096] As shown in the anti-interference algorithm module, the algorithm executed therein includes: Figure 4

[0097] 1) determining the interference judgment threshold according to the input spectrum X(k);

[0098] 2) setting k to zero and j to zero;

[0099] 3) judging whether j > 0.15N is true; if not, proceeding to the next step; if yes, the interference bandwidth is too wide, the data is unusable, and the processing process is ended;

[0100] 4) judging whether k < 1.5N is true; if yes, proceeding to the next step; if not, outputting the spectrum X_anti(k) removing the narrowband interference;

[0101] ​5) Determine whether X(k) is greater than the interference judgment threshold. If yes, then X(k) = 0, k = k + 1, j = j + 1; if no, then X(k) and j remain unchanged, and k = k + 1;

[0102] 6) Return to step 3).

[0103] Specifically, the signal extraction module includes an IFFT module and an extraction output module;

[0104] The IFFT module is used to perform 1.5N length IFFT on the frequency domain signal X_anti(k) after removing interference to obtain the time domain signal x new_anti (n), n = 1 to 1.5 N;

[0105] The extraction output module is used to extract the time domain signal x new_anti The length from point N / 2 to point N is the effective signal x of point N / 2. new_antiOut Output.

[0106]

[0107] In summary, the small-resource satellite navigation narrowband anti-interference device disclosed in the embodiment of the present invention can effectively suppress narrowband interference; and compared with the traditional double-window frequency domain method, the calculation amount is reduced by 25%, the frequency resolution is higher, the interference deduction is more accurate, and the damage to useful signals is less, which has important engineering value.

[0108] In the traditional double-window frequency domain method, FFT and IFFT select N as a power of 2. To obtain a segment of N / 2 interference-free data, two sets of N-point FFT and two sets of N-point inverse

[0109] FFT.

[0110] In the embodiment of the present invention, to obtain N / 2 points of interference-free data, it is necessary to calculate a set of 1.5N points FFT and 1.5N points inverse FFT; and the multiplication of another N-point FFT needs to be calculated.

[0111] N / 2*log2(N) complex multiplications and N*log2(N) complex multiplications and additions. A 1.5N-point FFT requires 1.5N / 2*log2(N) complex multiplications and 1.5Nlog2(N) complex additions.

[0112] N / 2 points of narrowband data are obtained. The computational complexity required by the traditional double-window frequency domain method and the embodiment of the present invention is shown in Table 1. Compared with the traditional double-window algorithm, the computational complexity is reduced by 25%.

[0113] Table 1 Comparison of computational complexity between the dual-window frequency domain algorithm and the patented algorithm

[0114] Conventional dual window frequency domain algorithm The present algorithm Complex multiplications 2N*log2(N) 1.5N*log2(N) Complex additions 4N*log2(N) 3N*log2(N)

[0115] Embodiment two

[0116] Another embodiment of the present application discloses a small resource satellite navigation narrowband anti-interference method, as shown in the figure, comprising the following steps: Figure 5

[0117] Step S1, taking out N-point data from the satellite navigation AD signal as the first signal and the satellite navigation AD signal after delaying N / 2 points as the second signal respectively for windowing processing; adding N / 2 zeros to the back of the first signal and the front of the second signal respectively after the windowing processing, and then performing data merging to obtain a synthesized signal with a length of 1.5N points;

[0118] Step S2, converting the synthesized signal into the frequency domain, and performing interference identification and removal in each frequency domain point respectively to obtain a frequency domain signal after interference removal;

[0119] Step S3, converting the frequency domain signal output by the interference identification and removal module into a time domain signal, and extracting an effective signal with a length of N / 2 points from N / 2 points to N points in the time domain signal for output; the effective signal is the signal of the second signal before interference removal;

[0120] In turn, the first and second signals are taken out for N points, and the processing of steps S1-S3 is performed on the satellite navigation AD signal sequence to perform narrowband anti-interference.

[0121] Specifically, in the step S1, the Blackman-Harris window is used to perform windowing processing on the N-point satellite navigation AD signal and the satellite navigation AD signal after delaying N / 2 points respectively.

[0122] Specifically, in the step S1, after adding 0.5N zeros to the front and back of the first signal and the second signal respectively after the windowing processing, the data is added to obtain a synthesized signal with a length of 1.5N points.

[0123] Specifically, the conversion of the synthesized signal into the frequency domain uses 1.5N-point FFT, and the conversion of the interference-removed frequency domain signal into the time domain uses 1.5N-point IFFT.

[0124] Specifically, in the step S2, the interference identification and removal process in each frequency domain point includes:

[0125] 1) determining the interference judgment threshold according to the input spectrum X(k);

[0126] 2) setting k to zero and j to zero;

[0127] 3) judging whether j>0.15N is true; if not, go to the next step; if yes, the interference bandwidth is too wide, the data is not available, and the processing process is ended; ​

[0128] 4) judge whether k<1.5N is true, if true, go to next step; if not, output the spectrum X_anti(k) after narrowband interference removal;

[0129] 5) judge whether X(k) is greater than interference judgment threshold, if yes, X(k)=0, k=k+1, j=j+1; if not, X(k), j remain unchanged, k=k+1;

[0130] 6) return to step 3).

[0131] The more specific technical details and beneficial effects in this embodiment are the same as those of the device described in Embodiment One, please refer to the description of Embodiment One for details, which will not be repeated here.

[0132] Embodiment Three

[0133] Another embodiment of the present application discloses a satellite navigation receiver, which comprises the small-resource satellite navigation narrowband interference rejection device as described in Embodiment One; the satellite navigation receiver removes the narrowband interference signal through the satellite navigation narrowband interference rejection device after AD processing of the received navigation satellite signal; and then performs capture and tracking processing on the AD signal after removal of the narrowband interference signal.

[0134] The specific content of the small-resource satellite navigation narrowband interference rejection device in this embodiment is described in Embodiment One, which will not be repeated here.

[0135] Embodiment Four

[0136] In another embodiment of the present application, a simulation experiment of narrowband interference rejection of a satellite navigation receiver is given.

[0137] Simulation conditions:

[0138] Signal: GPS L1 signal, bandwidth 2MHz, intermediate frequency 15.58MHz

[0139] Interference: the worst case is set, the center frequency is the same as the signal center frequency, i.e. 15.58Mhz, and the bandwidth is 0.2MHz

[0140] Sampling rate: 62MHz

[0141] Signal-to-interference ratio: 54dB

[0142] Carrier-to-noise ratio: 44dB / Hz

[0143] N: 512 points

[0144] Result verification: the capture result is the most effective for verifying the narrowband interference rejection effect.

[0145] Anti-interference mode:

[0146] Scheme 1 - double window frequency domain method;

[0147] Scheme 2 - small resource anti-interference method performed in embodiment one of the present application.

[0148] Simulation results:

[0149] Fig. 6 is a spectrum with a narrowband interference signal and a capture result,

[0150] Fig. 7 is a spectrum and a capture result after processing by scheme 1,

[0151] Fig. 8 is a spectrum and a capture result after processing by scheme 2.

[0152] From the spectrum of Figure 6-1 it can be seen that the narrowband interference at the center frequency of the signal is obviously higher than the signal, Figure 6-2 in the capture result of

[0153] Figure 7-1 it can be seen that the narrowband interference is suppressed after processing by the anti-narrowband method of scheme 1, Figure 7-2 the processed signal capture result shows a clear signal peak, and the capture is successful, and the signal after the double window frequency domain anti-interference can be normally used.

[0154] Figure 8-1 Fig. 8 is a spectrum and a capture result after processing by scheme 2. Figure 7-1 , it can be seen that the signal spectrum of scheme 2 is smoother and more continuous.

[0155] Figure 8-2 Fig. 8 is a spectrum and a capture result after processing by scheme 2.

[0156] It can be known through the verification of the simulation experiment that: the present application and the traditional double window frequency domain method can effectively suppress the narrowband interference, and after the suppression, the signal can be normally used, and the signal-to-noise ratio of the processed signal capture is equivalent.

[0157] However, the traditional double window frequency domain method needs to calculate two groups of N-point FFT and two groups of N-point IFFT for processing a segment of N / 2-point interference signal, and the calculation amount is large. The present application needs to calculate a group of 1.5N-point FFT and 1.5N-point IFFT for processing a segment of N / 2-point signal, and compared with the traditional double window frequency domain method, the calculation amount is reduced by 25%. In addition, qualitatively, the FFT point number of the present application is 1.5N points, and the frequency resolution is 0.5 times higher than that of the traditional method, the interference is more accurate, and the damage to the useful signal is smaller. The present application has important engineering value.

[0158] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A small-resource satellite navigation narrowband anti-interference device, characterized in that: include: A pre-processing module is used to extract N points of data from the satellite navigation AD signal as the first signal and the satellite navigation AD signal after the delay of N / 2 points as the second signal, and perform windowing processing on them; After the windowing process, N / 2 zeros are added to the back of the first signal and the front of the second signal, and then the data are merged to obtain a composite signal with a length of 1.5N points. An interference identification and removal module is used to convert the synthesized signal into the frequency domain, perform interference identification and removal at each frequency domain point, and obtain a frequency domain signal after interference removal; The signal extraction module is used to convert the frequency domain signal output by the interference identification and removal module into a time domain signal, extract the effective signal with a length of N / 2 points from point N / 2 to point N in the time domain signal, and output it; The signal extraction module includes an IFFT module and an extraction output module; The IFFT module is used to perform 1.5N length IFFT on the frequency domain signal after removing interference to obtain the time domain signal x new_anti (n), n = 1 to 1.5 N; The extraction output module is used to extract the time domain signal x new_anti In (n), the effective signal with a length of N / 2 points from point N to point N is output.

2. The narrowband anti-interference device for satellite navigation with small resources according to claim 1, characterized in that: The preprocessing module includes a first data cache module, a windowing module, a second data cache module, a zero-filling module, a third data cache module, a summing module and a fourth data cache module; The first group of data buffer modules includes two N-point data buffer areas, wherein the first N-point data buffer area is used to buffer the first-path signal of the N points, and the second N-point data buffer area is used to buffer the second-path signal of the N points; A windowing module, configured to perform windowing processing on the data in the first N-point data buffer area and the second N-point data buffer area respectively; The second group of data buffer modules includes two N-point data buffer areas, wherein the third N-point data buffer area is used to cache data after windowing the data in the first N-point data buffer area; and the fourth N-point data buffer area is used to cache data after windowing the data in the second N-point data buffer area. The third group of data cache modules includes two data cache areas with a length of 1.5N points, namely a first data cache area with a length of 1.5N points and a second data cache area with a length of 1.5N points; The zero-padding module adds N / 2 zeros to the end of the data in the third N-point data buffer area to form data with a length of 1.5N points and caches it in the first 1.5N-point data buffer area; and adds N / 2 zeros to the beginning of the data in the fourth N-point data buffer area to form data with a length of 1.5N points and caches it in the second 1.5N-point data buffer area; The summing module is configured to add and sum the cached data in the first 1.5N-point data cache area and the second 1.5N-point data cache area; The fourth group of data buffer modules includes a data buffer area with a length of 1.5N points, that is, a third data buffer area with a length of 1.5N points; it is used to buffer the summed data of a length of 1.5N points output by the summing module as a synthetic signal.

3. The narrowband anti-interference device for satellite navigation with small resources according to claim 2, characterized in that: The windowing module uses a Blackman-Harris window to perform windowing processing.

4. The narrowband anti-interference device for satellite navigation with small resources according to claim 2, characterized in that: The interference identification and removal module includes an FFT module and an anti-interference algorithm module; The FFT module is used to perform an FFT of 1.5N length on the synthesized signal to obtain a frequency domain signal; The anti-interference algorithm module is used to compare the amplitude of each frequency point of the frequency domain signal with a set interference judgment threshold, identify narrowband interference, determine the interfered frequency point, and remove the interference signal in the frequency point.

5. The small-resource satellite navigation narrowband anti-interference device according to claim 4, characterized in that: The algorithm executed in the anti-interference algorithm module includes: 1) Determine the interference judgment threshold based on the input spectrum X(k); 2) Set k to zero and j to zero; 3) Determine whether j>0.15N is true; if not, proceed to the next step; if yes, the interference bandwidth is too wide, the data is unusable, and the processing ends; 4) Determine whether k < 1.5N. If so, proceed to the next step. If not, output the spectrum X_anti(k) after removing the narrowband interference. 5) Determine whether X(k) is greater than the interference judgment threshold. If yes, then X(k) = 0, k = k + 1, j = j + 1; if no, then X(k) and j remain unchanged, and k = k + 1; 6) Return to step 3).

6. A small-resource satellite navigation narrowband anti-interference method using the small-resource satellite navigation narrowband anti-interference device according to any one of claims 1 to 5, characterized in that: include: Step S1, extracting N points of data from the satellite navigation AD signal as the first signal and the satellite navigation AD signal after being delayed by N / 2 points as the second signal, and performing windowing processing; After the windowing process, N / 2 zeros are added to the back of the first signal and the front of the second signal, and then the data are merged to obtain a composite signal with a length of 1.5N points. Step S2: converting the synthesized signal into the frequency domain, performing interference identification and removal at each frequency domain point, and obtaining a frequency domain signal after interference removal; Step S3: convert the frequency domain signal output by the interference identification and removal module into a time domain signal, extract the effective signal with a length of N / 2 points from point N / 2 to point N in the time domain signal, and output it.

7. The narrowband anti-interference method for satellite navigation with small resources according to claim 6, characterized in that: In step S1, a Blackman-Harris window is used to perform windowing processing on the satellite navigation AD signal at point N and the satellite navigation AD signal delayed by point N / 2.

8. The narrowband anti-interference method for satellite navigation with small resources according to claim 6, characterized in that: In step S2, the interference identification and removal process is performed at each frequency domain point, including: 1) Determine the interference judgment threshold based on the input spectrum X(k); 2) Set k to zero and j to zero; 3) Determine whether j>0.15N is true; if not, proceed to the next step; if yes, the interference bandwidth is too wide, the data is unusable, and the processing ends; 4) Determine whether k < 1.5N. If so, proceed to the next step. If not, output the spectrum X_anti(k) after removing the narrowband interference. 5) Determine whether X(k) is greater than the interference judgment threshold. If yes, then X(k) = 0, k = k + 1, j = j + 1; if no, then X(k) and j remain unchanged, and k = k + 1; 6) Return to step 3).

9. A satellite navigation receiver, characterized in that: include: The small-resource satellite navigation narrowband anti-interference device according to any one of claims 1 to 5; After the satellite navigation receiver performs AD processing on the received navigation satellite signal, the satellite navigation narrowband anti-interference device removes the narrowband interference signal; The AD signal after the narrowband interference signal is removed is then captured and tracked.

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