Small-resource satellite navigation narrow-band anti-interference device and method and receiver

Abstract

The invention relates to a small-resource satellite navigation narrow-band anti-interference device and method and a receiver, and belongs to the technical field of satellite navigation, and the device comprises a preprocessing module which is used for respectively extracting N-point data from a satellite navigation AD signal as a first-path signal and a satellite navigation AD signal which is used as a second-path signal and is delayed by N / 2 points for windowing processing; respectively adding N / 2 zeros behind the windowed first path of signal and in front of the windowed second path of signal, and then carrying out data combination to obtain a composite signal with the length of 1.5 N points; the interference identification and removal module is used for converting the synthetic signal into a frequency domain, and performing interference identification and removal in each frequency domain point to obtain a frequency domain signal after interference removal; and the signal extraction module 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 the length of N / 2 points from N / 2 points to N points in the time domain signal, and outputting the effective signal. The calculation amount is reduced, the occupied resources are few, and the power consumption is low.

Description

Technical Field

[0001] The present invention relates to the field of satellite navigation technology, and in particular to a small-resource satellite navigation narrowband anti-interference device, method and receiver. Background Art

[0002] Satellite navigation positioning has the characteristics of global coverage, all-weather, and high precision, and is widely used in weapons, transportation, precision agriculture, marine fisheries, finance and electricity, mobile terminals and other fields. However, in actual applications, satellite navigation receivers face various interferences, one of which is narrowband interference. Narrowband interference refers to interference with a spectrum of less than or equal to 10% of the total bandwidth, which is usually emitted by electromagnetic sources and lasts for a long time, directly affecting the normal operation of the receiver. The ability of satellite navigation receivers to resist narrowband interference is an important capability indicator of satellite navigation receivers.

[0003] There are two types of narrowband interference prevention: time domain filtering and frequency domain filtering. The time domain algorithm is generally more complex and suitable for suppressing slowly changing interference, but has a slightly poorer ability to adapt to the environment. The spatial domain algorithm has a better anti-interference effect, but due to the limitation of hardware cost, it requires a higher investment. Relatively speaking, the frequency domain anti-interference technology is relatively simple to implement, and has a better suppression effect on single-frequency interference and partial frequency band interference, and its application range is relatively wide. Traditional satellite navigation receivers use a double-window frequency domain method to resist narrowband. In the double-window frequency domain method, to process a segment of N / 2 point signals, it is necessary to calculate two groups of N-point FFTs and two groups of N-point inverse FFTs. The amount of calculation is relatively large, and the corresponding resources are high and the power consumption is high. Summary of the invention

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

[0005] The present invention discloses a small-resource satellite navigation narrowband anti-interference device, comprising:

[0006] The preprocessing 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 for windowing processing; N / 2 zeros are added to the back of the first signal and the front of the second signal after the windowing processing, and then the data are merged to obtain a synthetic signal with a length of 1.5N points;

[0007] 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 the interference is removed;

[0008] 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 for output; the effective signal is the signal of the first N / 2 points of the second signal after the interference is removed.

[0009] Further, the preprocessing module includes a first group of data cache modules, a windowing module, a second group of data cache modules, a zero-filling module, a third group of data cache modules, a summing module and a fourth group of data cache modules;

[0010] The first group of data cache modules includes two N-point data cache areas, wherein the first N-point data cache area is used to cache the first-path signal of the N points, and the second N-point data cache area is used to cache the second-path signal of the N points;

[0011] A windowing module, 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;

[0012] The second group of data cache modules includes two N-point data cache areas, wherein the third N-point data cache area is used to cache the data after windowing processing of the first N-point data cache area; the fourth N-point data cache area is used to cache the data after windowing processing of the second N-point data cache area;

[0013] The third group of data cache modules includes two data cache areas with a length of 1.5N points, 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;

[0014] The zero-padding module pads N / 2 zeros at 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; pads N / 2 zeros at 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;

[0015] The summing module is used to add and sum the cached data in the data cache area of ​​the first 1.5N points and the data cache area of ​​the second 1.5N points;

[0016] The fourth group of data cache modules includes a data cache area with a length of 1.5N points and a third data cache area with a length of 1.5N points; and is used to cache the summed data with a length of 1.5N points output by the summing module as a synthetic signal.

[0017] Furthermore, the windowing module uses a Blackman-Harris window to perform windowing processing.

[0018] Furthermore, the interference identification and removal module includes an FFT module and an anti-interference algorithm module;

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

[0020] The anti-interference algorithm module is used to compare the amplitude of each frequency point of the frequency domain signal with the set interference judgment threshold, identify narrowband interference, determine the interfered frequency point, and remove the interference signal in the frequency point.

[0021] Furthermore, the algorithm executed in the anti-interference algorithm module includes:

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

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

[0024] 3) Determine whether j>0.15N is established; if not, proceed to the next step; if yes, the interference bandwidth is too wide, the data is unavailable, and the processing process ends;

[0025] 4) Determine whether k < 1.5N is true, if so, proceed to the next step; if not, output the spectrum X_anti(k) after removing narrowband interference;

[0026] 5) Determine whether X(k) is greater than the interference judgment threshold. If yes, X(k)=0, k=k+1, j=j+1; if no, X(k) and j remain unchanged, k=k+1;

[0027] 6) Return to step 3).

[0028] Furthermore, the signal extraction module includes an IFFT module and an extraction output module;

[0029] The IFFT module is used to perform an IFFT of 1.5N length on the frequency domain signal after interference removal to obtain a time domain signal;

[0030] The extraction and output module is used to extract and output a valid signal with a length of N / 2 points from point N / 2 to point N in the time domain signal.

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

[0032] Step S1, extracting N points of data from the satellite navigation AD signal as the first signal and the satellite navigation AD signal after delay of N / 2 points as the second signal for windowing processing; adding N / 2 zeros to the back of the first signal and the front of the second signal after the windowing processing, and then merging the data to obtain a synthetic signal with a length of 1.5N points;

[0033] 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 the interference is removed;

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

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

[0036] Furthermore, 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 respectively.

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

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

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

[0040] 3) Determine whether j>0.15N is established; if not, proceed to the next step; if yes, the interference bandwidth is too wide, the data is unavailable, and the processing process ends;

[0041] 4) Determine whether k < 1.5N is true, if so, proceed to the next step; if not, output the spectrum X_anti(k) after removing narrowband interference;

[0042] 5) Determine whether X(k) is greater than the interference judgment threshold. If yes, X(k)=0, k=k+1, j=j+1; if no, X(k) and j remain unchanged, k=k+1;

[0043] 6) Return to step 3).

[0044] Another aspect of the present invention 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 removes the narrowband interference signal; and then captures and tracks the AD signal after the narrowband interference signal is removed.

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

[0047] The small-resource satellite navigation narrowband anti-interference device, method and receiver disclosed in 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 smaller, which has important engineering value. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The drawings are only for the purpose of illustrating specific embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0049] Figure 1 A connection block diagram of a small-resource satellite navigation narrowband anti-interference device according to an embodiment of the present invention;

[0050] Figure 2 A connection block diagram of the preprocessing module in the embodiment of the present invention;

[0051] Figure 3 is a time-frequency characteristic diagram of the window function in an embodiment of the present invention;

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

[0053] Figure 5 This is a flow chart of a narrowband anti-interference method for satellite navigation with small resources in an embodiment of the present invention;

[0054] Figure 6-1 is a spectrum diagram of a narrowband interference signal in an embodiment of the present invention;

[0055] Figure 6-2 is a capture result diagram of a narrowband interference signal in an embodiment of the present invention;

[0056] Figure 7-1 This is the spectrum diagram of Scheme 1 after anti-narrowband interference;

[0057] Figure 7-2 This is the capture result diagram of Scheme 1 after resisting narrowband interference;

[0058] Figure 8-1 This is the spectrum diagram of Scheme 2 after anti-narrowband interference;

[0059] Figure 8-2 This is the capture result diagram after Scheme 2 resists narrowband interference. DETAILED DESCRIPTION

[0060] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used to illustrate the principles of the present invention together with the embodiments of the present invention.

[0061] Embodiment 1

[0062] One embodiment of the present invention discloses a small-resource satellite navigation narrowband anti-interference device, such as Figure 1 As shown, including:

[0063] The preprocessing 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 for windowing processing; N / 2 zeros are added to the back of the first signal and the front of the second signal after the windowing processing, and then the data are merged to obtain a synthetic signal with a length of 1.5N points;

[0064] 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 the interference is removed;

[0065] 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 for output; the effective signal is the signal of the first N / 2 points of the second signal after the interference is removed.

[0066] The satellite navigation AD signal sequence is subjected to narrow-band anti-interference by successively taking out N points, synthesizing, identifying and removing interference, and extracting the first and second signals.

[0067] like Figure 2 As shown, the preprocessing module includes: a first group of data cache modules, a windowing module, a second group of data cache modules, a zero-filling module, a third group of data cache modules, a summing module and a fourth group of data cache modules;

[0068] The first group of data cache modules includes two N-point data cache areas, wherein the first N-point data cache area is used to cache the first signal x of the N points. 1_pre (n), the second N-point data buffer area, used to buffer the second signal x of the N-point 2_pre (n); n = 1 to N;

[0069] A windowing module, 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 rectangular window function has high side lobes, which causes the signal to have large spectrum leakage. Windowing can effectively improve this. Commonly used window functions include Hamming window, Blackman window, Blackman Harris window, etc.

[0071] like Figure 3 Shown is the time-frequency characteristic diagram of the window function.

[0072] Preferably, a Blackman-Harris window is used for windowing processing, because the Blackman-Harris window has lower side lobes, which can reduce spectrum leakage;

[0073] 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 buffer the data x1(n) after windowing the first N-point data buffer area; the fourth N-point data buffer area is used to buffer the data x2(n) after windowing the second N-point data buffer area;

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

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

[0076] Where win(n) is the Blackman-Harris window;

[0077] The third group of data cache modules includes two data cache areas with a length of 1.5N points, 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;

[0078] The zero-filling module fills N / 2 zeros after the data in the third N-point data buffer area to form a data x with a length of 1.5N points. 1_0 (n) Cache to the first 1.5N point data cache area; Add N / 2 zeros to the front of the data in the fourth N point data cache area to form a data x with a length of 1.5N points 2_0 (n) Cache to the data cache area of ​​the second 1.5N points; n = 1 to 1.5N;

[0079] The summing module is used to add and sum the cached data in the data cache area of ​​the first 1.5N points and the data cache area of ​​the second 1.5N points;

[0080] The fourth group of data cache modules includes a data cache area with a length of 1.5N points and a third data cache area with a length of 1.5N points; and is used to cache the summed data x with a length of 1.5N points output by the summing module. new (n), as a composite 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 includes an FFT module and an anti-interference algorithm module;

[0083] The FFT module is used to perform a 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 used to compare the amplitude of each frequency point of the frequency domain signal X(k) with the set interference judgment threshold, identify narrowband interference, determine the interfered frequency point, and remove the interference signal in the frequency point;

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

[0086]

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

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

[0089]

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

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

[0092]

[0093] The false alarm rate is:

[0094]

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

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

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

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

[0099] 3) Determine whether j>0.15N is established; if not, proceed to the next step; if yes, the interference bandwidth is too wide, the data is unavailable, and the processing process ends;

[0100] 4) Determine whether k < 1.5N is true, if so, proceed to the next step; if not, output the spectrum X_anti(k) after removing narrowband interference;

[0101] 5) Determine whether X(k) is greater than the interference judgment threshold. If yes, X(k)=0, k=k+1, j=j+1; if no, X(k) and j remain unchanged, 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 an IFFT of length 1.5N on the frequency domain signal X_anti(k) after the interference is removed to obtain a time domain signal x new_anti (n), n = 1 ~ 1.5N;

[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 amount of calculation is reduced by 25%, the frequency resolution is higher, the interference deduction is more accurate, and the damage to useful signals is smaller, 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 points of 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, a set of 1.5N-point FFT and 1.5N-point inverse FFT needs to be calculated; another N-point FFT needs to calculate the multiplication

[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, and the amount of calculation 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 amount of calculation is reduced by 25%.

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

[0114] Traditional dual-window frequency domain algorithm This patented algorithm Multiple times 2N*log2(N) 1.5N*log2(N) Add (times) 4N*log2(N) 3N*log2(N)

[0115] Embodiment 2

[0116] Another embodiment of the present invention discloses a small resource satellite navigation narrowband anti-interference method, such as Figure 5 As shown, the following steps are included:

[0117] Step S1, extracting N points of data from the satellite navigation AD signal as the first signal and the satellite navigation AD signal after delay of N / 2 points as the second signal for windowing processing; adding N / 2 zeros to the back of the first signal and the front of the second signal after the windowing processing, and then merging the data to obtain a synthetic signal with a length of 1.5N points;

[0118] 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 the interference is removed;

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

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

[0121] Specifically, in step S1, the 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 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 after the windowing process, data are added to obtain a synthetic signal with a length of 1.5N points.

[0123] Specifically, a 1.5N-point FFT is used to convert the synthesized signal into the frequency domain, and a 1.5N-point IFFT is used to convert the frequency domain signal after the interference is removed into the time domain.

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

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

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

[0127] 3) Determine whether j>0.15N is established; if not, proceed to the next step; if yes, the interference bandwidth is too wide, the data is unavailable, and the processing process ends;

[0128] 4) Determine whether k < 1.5N is true, if so, proceed to the next step; if not, output the spectrum X_anti(k) after removing narrowband interference;

[0129] 5) Determine whether X(k) is greater than the interference judgment threshold. If yes, X(k)=0, k=k+1, j=j+1; if no, X(k) and j remain unchanged, k=k+1;

[0130] 6) Return to step 3).

[0131] The more specific technical details and beneficial effects of this embodiment are the same as those of the device described in Example 1. Please refer to them for details and will not be described in detail here.

[0132] Embodiment 3

[0133] Another embodiment of the present invention discloses a satellite navigation receiver, which includes a small-resource satellite navigation narrowband anti-interference device as described in Example 1; 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; and then captures and tracks the AD signal after the narrowband interference signal is removed.

[0134] For the specific contents of the small-resource satellite navigation narrowband anti-interference device described in this embodiment, please refer to Embodiment 1, which will not be described in detail here.

[0135] Embodiment 4

[0136] Another embodiment of the present invention provides a simulation experiment of a satellite navigation receiver against narrowband interference;

[0137] Simulation conditions:

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

[0139] Interference: Set the worst case, the center frequency is the same as the signal center frequency, that is, 15.58Mhz, bandwidth 0.2MHz

[0140] Sampling rate: 62MHz

[0141] Interference-to-signal ratio: 54dB

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

[0143] N: 512 points

[0144] Result verification: It is most effective to verify the anti-narrowband interference effect by capturing the results.

[0145] Anti-interference method:

[0146] Solution 1 - Double-window frequency domain method;

[0147] Solution 2 - the small resource anti-interference method implemented in the first embodiment of the present invention.

[0148] Simulation results:

[0149] Figure 6 shows the spectrum and capture results of a narrowband interference signal.

[0150] Figure 7 shows the spectrum and capture results after processing by Scheme 1.

[0151] Figure 8 shows the spectrum and capture results after processing by Scheme 2.

[0152] Depend on Figure 6-1 It can be seen from the spectrum that the narrowband interference at the center frequency of the signal is significantly higher than the signal. Figure 6-2 It can be seen from the capture results that the satellite signal cannot be captured due to the influence of narrowband interference.

[0153] Figure 7-1 It can be seen that after the anti-narrowband method of scheme 1 is processed, the narrowband interference is suppressed. Figure 7-2 The signal capture result after processing shows that there is an obvious signal peak, and the capture is successful. The signal can be used normally after dual-window frequency domain anti-interference.

[0154] Figure 8-1 This is the spectrum after processing by Scheme 2. It can be seen that the small resource anti-interference method of Scheme 2 effectively suppresses narrowband interference. Figure 7-1 , it can be seen that the signal spectrum of scheme 2 is smoother and more continuous.

[0155] Figure 8-2 This is the signal capture result after anti-interference processing of Scheme 2, and there is an obvious signal peak captured successfully.

[0156] It can be verified through simulation experiments that the present invention and the traditional double-window frequency domain method can effectively suppress narrowband interference, so that the signal can be used normally after suppression, and the signal capture signal-to-noise ratio after processing 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 to process a section of N / 2-point interference signal, which requires a large amount of calculation. The present invention processes a section of N / 2-point signal, which requires calculating a group of 1.5N-point FFT and 1.5N-point IFFT, which reduces the amount of calculation by 25% compared with the traditional double-window frequency domain method. In addition, qualitatively speaking, the number of FFT points of the present invention is 1.5N points, the frequency resolution is 0.5 times higher than that of the traditional method, the interference deduction is more accurate, and the damage to the useful signal is smaller. The present invention has important engineering value.

[0158] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A small-resource satellite navigation narrowband anti-interference device, characterized in that: include: A preprocessing 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 delay of N / 2 points as the second signal, and perform 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 synthetic 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 the interference is removed; 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 for output; the effective signal is the signal of the first N / 2 points of the second signal after the interference is removed.

2. The small-resource satellite navigation narrowband anti-interference device according to claim 1 is characterized in that: The preprocessing module includes a first group of data cache modules, a windowing module, a second group of data cache modules, a zero-filling module, a third group of data cache modules, a summing module and a fourth group of data cache modules; The first group of data cache modules includes two N-point data cache areas, wherein the first N-point data cache area is used to cache the first-path signal of the N points, and the second N-point data cache area is used to cache the second-path signal of the N points; A windowing module, 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; The second group of data cache modules includes two N-point data cache areas, wherein the third N-point data cache area is used to cache the data after windowing processing of the first N-point data cache area; the fourth N-point data cache area is used to cache the data after windowing processing of the second N-point data cache area; The third group of data cache modules includes two data cache areas with a length of 1.5N points, 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 pads N / 2 zeros at 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; pads N / 2 zeros at 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 used to add and sum the cached data in the data cache area of ​​the first 1.5N points and the data cache area of ​​the second 1.5N points; The fourth group of data cache modules includes a data cache area with a length of 1.5N points and a third data cache area with a length of 1.5N points; and is used to cache the summed data with a length of 1.5N points output by the summing module as a synthetic signal.

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

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

6. The small-resource satellite navigation narrowband anti-interference device according to claim 2, characterized in that: The signal extraction module includes an IFFT module and an extraction output module; The IFFT module is used to perform an IFFT of 1.5N length on the frequency domain signal after interference removal to obtain a time domain signal; The extraction and output module is used to extract and output a valid signal with a length of N / 2 points from point N / 2 to point N in the time domain signal.

7. A small-resource satellite navigation narrowband anti-interference method, characterized in that: include: Step S1, taking out N points of data from the satellite navigation AD signal as the first signal and the satellite navigation AD signal after delay of 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 synthetic 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 the interference is removed; Step S3, converting the frequency domain signal output by the interference identification and removal module into a time domain signal, extracting a valid signal with a length of N / 2 points from point N / 2 to point N in the time domain signal for output; the valid signal is the signal of the first N / 2 points of the second signal after the interference is removed; N points are taken out from the first and second signals in sequence, and the processing of steps S1 to S3 is performed to perform narrow-band anti-interference on the satellite navigation AD signal sequence.

8. The small-resource satellite navigation narrowband anti-interference method according to claim 7, 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.

9. The small-resource satellite navigation narrowband anti-interference method according to claim 7, characterized in that: In step S2, the interference identification and removal process at each frequency domain point includes: 1) Determine the interference judgment threshold according to the input spectrum X(k); 2) Set k to zero and j to zero; 3) Determine whether j>0.15N is established; if not, proceed to the next step; if yes, the interference bandwidth is too wide, the data is unavailable, and the processing process ends; 4) Determine whether k < 1.5N is true, if so, proceed to the next step; if not, output the spectrum X_anti(k) after removing narrowband interference; 5) Determine whether X(k) is greater than the interference judgment threshold. If yes, X(k)=0, k=k+1, j=j+1; if no, X(k) and j remain unchanged, k=k+1; 6) Return to step 3).

10. A satellite navigation receiver, characterized in that: include: A small-resource satellite navigation narrowband anti-interference device as described in any one of claims 1 to 6; 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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