High-precision anti-jamming navigation with strong short-delay deception jamming detection and suppression method

Abstract

The present invention relates to the technical field of high-precision anti-interference satellite navigation, and specifically discloses a method for detecting and suppressing strong short-delay deception interference of high-precision anti-interference navigation, including: judging whether there is deception interference by suppressing the satellite signal to be detected and highlighting the deception interference; if there is deception interference, estimating its amplitude and phase, and restoring the deception interference; subtracting the recovered deception interference from the received signal to reduce the residual deception interference intensity in the received signal to less than 10dB; adding a correlator to the PAC method, using the correlator to search for correlation peaks in ~ code chip areas, using the correlator to correct the phase detection function, and then eliminating the residual deception interference. The present invention can detect whether there is deception interference and the satellite signal that the deception interference is intended to replace, and guide the subsequent deception interference suppression; combining the deception interference recovery and cancellation method with the improved PAC method, systematically solves the problem of suppressing strong short-delay deception interference.

Description

Technical Field

[0001] The present invention relates to the technical field of high-precision anti-interference satellite navigation, and in particular to a method for detecting and suppressing strong short-delay deception interference in high-precision anti-interference navigation. Background Art

[0002] The outstanding features of high-precision anti-interference satellite navigation applications such as precision approach and landing of aircraft, landing of aircraft on aircraft carriers, formation flying and automatic aerial refueling, rapid direction finding and autonomous north seeking of missile launchers / aircraft are complex interference environments and high requirements for positioning and orientation.

[0003] The complexity of the interference environment is mainly manifested in the variety of interference types and changes. From the perspective of interference mechanism, the interference types are divided into suppression interference, deception interference, and suppression and deception combined interference. Deception interference is further divided into regeneration and forwarding types. Interference changes mainly include the number, direction, modulation, frequency, intensity, etc. of interference that changes rapidly or slowly over time. Positioning and orientation requirements include real-time or near real-time positioning services at the decimeter / centimeter level and orientation services better than 1 degree / 0.5 degree.

[0004] High-precision positioning and orientation in complex interference environments requires solving three strongly coupled problems: complex interference detection and real-time suppression, satellite signal distortion tracing and control, and high-precision positioning and orientation with low distortion.

[0005] In the present invention, the inventors decoupled the above three problems into three categories, seven subcategories, and 10 sequential topics as shown in the following table through theoretical deduction, simulation analysis and experimental verification.

[0006] Based on this, 10 high-precision anti-interference navigation invention patents corresponding to the above topics are planned and laid out, as shown in Table 1.

[0007] Table 1 List of decoupling and disassembly of high-precision positioning and orientation problems in complex interference environments

[0008]

[0009] The present invention analyzes and explains the first category, the second subcategory, and the fourth invention listed in the above table - a method for detecting and suppressing strong short-delay deception interference.

[0010] The intensity and delay of deceptive interference directly determine the deceptive effect. If the deceptive interference power is strong and the signal-to-interference ratio is greater than 40dB, it will trigger the anti-interference array antenna to suppress it, and it will be easily detected by the navigation equipment, which will eventually make the deceptive interference ineffective. If the deceptive interference power is weak, it will have little effect on the capture and tracking of satellite signals, which is invalid deceptive interference. If the relative delay of the deceptive interference is long, the delay is greater than 1.5 chips, and the conventional tracking loop can eliminate its influence, which is also invalid deceptive interference. If the relative delay of the deceptive interference is very short, the delay is shorter than 0.2 chips, the delay control accuracy requirements are very high, and it is very difficult to implement.

[0011] The dilemma of strong / weak power and long / very short delay deception interference forces the implementers of deception interference to adopt stronger short delay deception interference. Stronger and short delay deception interference refers to deception interference with a signal-to-noise ratio between 20dB and 40dB and a delay between 0.2 and 1.5 chips.

[0012] Existing deception interference detection methods include carrier-to-noise ratio detection, correlation peak detection, etc. Existing deception interference suppression methods include correlation peak screening, narrow correlation (NC), micro-pulse correlation (PAC), etc.

[0013] The mechanism of the carrier-to-noise ratio detection method: Except for the case of increased satellite signal power during wartime, the ratio of the satellite signal power received by the navigation device to the noise power spectrum density (referred to as the carrier-to-noise ratio) will not change much. When there is deception interference with a power stronger than the satellite signal, the carrier-to-noise ratio received by the navigation device will increase. Accordingly, when the received carrier-to-noise ratio exceeds the preset reasonable range, it is judged that deception interference exists; otherwise, it is judged that there is no deception interference.

[0014] The mechanism of the correlation peak detection method: the satellite signal adopts a direct sequence spread spectrum system, in which the spread spectrum sequence is a pseudo-random code sequence with sharp autocorrelation characteristics and flat cross-correlation characteristics. If there is deception interference, there will be more than one sharp correlation peak in the two-dimensional search space (pseudo-random code phase, Doppler frequency shift). If the number of correlation peaks detected is 1, it is judged that there is no deception interference; if the number of correlation peaks is greater than 1, it is judged that there is deception interference.

[0015] The mechanism of the correlation peak screening method is: after the detection of deception interference (i.e. the number of correlation peaks is greater than 1), considering that deception interference, especially forwarding interference, usually lags behind the satellite signal, the correlation peaks with earlier pseudo code delay are screened out and enter the tracking phase; the correlation peaks with later pseudo code delay are discarded and do not enter the tracking phase.

[0016] The mechanism of the narrow correlation method: The pseudo-code tracking phase function based on the early-late correlator is related to the correlation interval, and thus the pseudo-range error envelope is related to the correlation interval. The narrower the correlation interval, the flatter and narrower the pseudo-range error envelope, which can suppress the delay greater than Deceptive interference of one code chip.

[0017] The mechanism of the micro-pulse correlation method is: a total of 4 correlators are used in two groups of wide correlation and narrow correlation, among which the interval between the early-late wide correlators (E2-L2) is , which is twice the interval of the early-late narrow correlator (E1-L1). The micro-pulse correlation method has a stronger ability to suppress short-delay deception interference than the narrow correlation method, and can suppress delays between ~ chips and greater than Deceptive interference of one code chip.

[0018] The performance of existing carrier-to-noise ratio detection methods strongly depends on the preset reasonable range. If the preset reasonable range is wide, the detection rate is low, and if the preset reasonable range is narrow, the false alarm rate is high. The received carrier-to-noise ratio is related to many factors such as satellite altitude angle, satellite signal type, navigation equipment antenna attitude and gain pattern. The range of the received carrier-to-noise ratio cannot be very narrow, so the preset reasonable range cannot be very narrow, which leads to a low detection rate and a high missed detection rate of deception interference.

[0019] The correlation peak detection and screening method cannot detect and suppress strong short-delay deception interference. The narrow correlation method and micro-pulse correlation method are also unable to suppress strong short-delay deception interference. The specific analysis is as follows.

[0020] (1) Correlation peak detection and screening method:

[0021] The strong short-delay deception interference makes it difficult to distinguish the main peak and sidelobe of the correlation function between the received signal (including satellite signal and deception interference) and the local pseudo-random code at the real pseudo-code delay, and makes the correlation peak at the deception pseudo-code delay very prominent.

[0022] When the interference-to-signal ratio is 6dB, the correlation peak distribution with a coherent accumulation time of 2ms is as follows: Figure 1 When the interference-to-signal ratio is 20dB, the correlation peak distribution with a coherent accumulation time of 2ms is as follows: Figure 1 As shown in the right figure of . In the figure, P1 indicates the real pseudo code delay and the main peak at the Doppler frequency of 2kHz, and P2 indicates the deceptive pseudo code delay and the main peak at the Doppler frequency of -2kHz.

[0023] Comparing the two figures, we can see that when the intensity of the deceptive interference is 20dB, the real main peak is submerged. In this way, the delayed correlation peak elimination method only identifies the P2 main peak, and naturally mistakes it for the real main peak, and mistakes the deceptive interference for the satellite signal, and then regards the P2 delay and Doppler frequency as the real pseudo code delay and Doppler frequency, which ultimately leads to errors in the position velocity time (PVT) solution.

[0024] (2) Narrow correlation method:

[0025] The linear region of the phase detector function of the narrow correlation method is ; When the relative delay is between ~ When the relative delay is between When the relative delay is greater than When the tracking error is 0.

[0026] exist When the value is 0.2, the relationship between the pseudo-code tracking error of the narrow correlation method and the relative delay of the deception interference is as follows: Figure 2 shown.

[0027] Figure 2 It shows that for short-delay deception jammers with a delay between 0.2 and 1.5 chips, deception jammers with a delay between 0.2 and 1.1 chips will cause the narrow correlation method to produce larger pseudo-code tracking errors.

[0028] (3) Micropulse correlation (PAC) method:

[0029] The linear region of the phase detector function of the PAC method is , when the relative delay is between When the relative delay is between ~ When the relative delay is between ~ When the relative delay is greater than When the tracking error is 0.

[0030] exist When the value is 0.2, the relationship between the pseudo-code tracking error of the PAC method and the relative delay of the deception interference is as follows: Figure 3 shown.

[0031] Figure 3 It shows that for short-delay deception jammers with a delay between 0.2 and 1.5 chips, deception jammers with a delay between 0.8 and 1.2 chips will cause the PAC method to produce larger pseudo-code tracking errors.

[0032] Based on this technical background, the present invention studies a method for detecting and suppressing strong short-delay deception interference for high-precision anti-interference navigation. Summary of the invention

[0033] In view of the deficiencies in the prior art, the present invention provides a method for detecting and suppressing relatively strong short-delay deception interference for high-precision anti-interference navigation. The method adopts the detection idea of ​​suppressing satellite signals and highlighting deception interference, and can detect whether there is deception interference and the satellite signal that the deception interference is intended to replace, and guide the subsequent deception interference suppression. The method also adopts the suppression idea of ​​first recovering, then canceling, and then phase detection, and combines the deception interference recovery and cancellation method with the improved PAC method, thereby systematically solving the problem of suppressing relatively strong short-delay deception interference.

[0034] In order to achieve the above-mentioned object, the present invention provides a method for detecting and suppressing strong short-delay deception interference of high-precision anti-interference navigation, comprising:

[0035] By suppressing the signal of the satellite to be detected and highlighting the deception interference, it is determined whether there is strong short-delay deception interference;

[0036] If there is deceptive interference, estimate its amplitude and phase, and restore the deceptive interference;

[0037] Subtract the recovered deception interference from the received signal to reduce the residual deception interference strength in the received signal to below -10dB;

[0038] Add a correlator to the PAC method and use the correlator to search ~ The correlation peak in the chip area is used to correct the phase detection function to eliminate residual deception interference.

[0039] The beneficial effects of the present invention include:

[0040] (1) The method for detecting and suppressing strong short-delay deceptive interference for high-precision anti-interference navigation proposed in the present invention adopts the detection idea of ​​suppressing satellite signals and highlighting deceptive interference. It can detect whether there is deceptive interference and the satellite signal that the deceptive interference is intended to replace, and guide the subsequent deceptive interference suppression; and adopts the suppression idea of ​​first recovery, then cancellation, and then phase detection, combining the deceptive interference recovery and cancellation method with the improved PAC method, systematically solving the problem of suppressing strong short-delay deceptive interference.

[0041] (2) The method for detecting and suppressing strong short-delay deceptive interference for high-precision anti-interference navigation proposed in the present invention is based on the characteristic that the signal-to-noise ratio of strong short-delay deceptive interference is between 20dB and 40dB. By creating a virtual medium-intensity interference in the upward direction of the signal of the satellite to be detected, the array antenna forms a null in the upward direction to suppress the satellite signal, thereby "highlighting" the deceptive interference, and then detecting whether there is deceptive interference and the satellite signal that the deceptive interference is intended to replace.

[0042] (3) The method for detecting and suppressing strong short-delay deception interference for high-precision anti-interference navigation proposed in the present invention aims at the characteristics of strong short-delay deception interference, that is, the interference-to-signal ratio is between 20dB and 40dB and the delay is between 0.2 and 1.5 code chips. First, the amplitude and phase of the deception interference are estimated, and then the deception interference is restored. Then, the recovered deception interference is subtracted from the received signal to suppress most of the deception interference in the received signal, so that the residual deception interference intensity is reduced to below -10dB. Finally, an improved PAC method including 5 correlators is used to eliminate the residual deception interference. When the deception interference delay is between 0.2 and 1.2 code chips, the tracking error is 0, which systematically solves the problem of suppressing strong short-delay deception interference.

[0043] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

[0045] Figure 1 This is a schematic diagram of the results of correlation between the received signal and the pseudo-random code when the interference-to-signal ratio is 6dB and 20dB in the existing correlation peak detection and screening method.

[0046] Figure 2 This is a diagram showing the relationship between the pseudo-code tracking error and the relative delay of the deception interference of the existing narrow correlation method.

[0047] Figure 3 This is a diagram showing the relationship between the pseudo-code tracking error and the relative delay of the deception interference of the existing PAC method.

[0048] Figure 4 It is a flow chart of the method for detecting and suppressing strong short-delay deception interference for high-precision anti-interference navigation proposed by the present invention.

[0049] Figure 5 This is a schematic diagram of the spatial distribution scenario of satellites to be detected in a specific implementation of the method for detecting and suppressing strong short-delay deception interference in high-precision anti-interference navigation proposed by the present invention.

[0050] Figure 6 This is a schematic diagram of the array antenna gain pattern for suppressing the satellite signal to be detected in a specific implementation of the method for detecting and suppressing strong short-delay deception interference for high-precision anti-interference navigation proposed by the present invention.

[0051] Figure 7 This is a schematic diagram of the correlation results after recovery cancellation when the signal-to-noise ratio is 20dB and 40dB in a specific implementation of the method for detecting and suppressing strong short-delay deception interference for high-precision anti-interference navigation proposed by the present invention.

[0052] Figure 8 This is a schematic diagram of the effect of the deceptive interference delay between 1 and 1+d code chips on the original correlator in a specific implementation of the method for detecting and suppressing deceptive interference with strong short delay for high-precision anti-interference navigation proposed by the present invention.

[0053] Fig. 9 This is a schematic diagram of the effect of the deceptive interference delay between 1-d and 1 code chip on the original correlator in a specific implementation of the method for detecting and suppressing deceptive interference with strong short delay for high-precision anti-interference navigation proposed by the present invention.

[0054] Fig.10 This is a schematic diagram of the theoretical tracking error of the improved PAC method in a specific implementation of the method for detecting and suppressing strong short-delay deception interference for high-precision anti-interference navigation proposed by the present invention. DETAILED DESCRIPTION

[0055] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0056] The present invention provides a method for detecting and suppressing short-delay deception interference for high-precision anti-interference navigation. Figure 1 As shown, including:

[0057] By suppressing the signal of the satellite to be detected and highlighting the deception interference, it is determined whether there is strong short-delay deception interference;

[0058] If there is deceptive interference, estimate its amplitude and phase, and restore the deceptive interference;

[0059] Subtract the recovered deception interference from the received signal to reduce the residual deception interference strength in the received signal to below -10dB;

[0060] Add a correlator to the PAC method and use it to search ~ The correlation peak in the chip area is used to correct the phase detection function to eliminate residual deception interference.

[0061] In the present invention, the detection idea of ​​suppressing satellite signals and highlighting deceptive interference is adopted, so as to detect whether there is deceptive interference and the satellite signal that the deceptive interference is intended to replace, and guide the subsequent deceptive interference suppression; and the suppression idea of ​​first recovery, then cancellation, and then phase detection is adopted, and the deceptive interference recovery and cancellation method is combined with the improved PAC method, so as to systematically solve the problem of suppressing strong short-delay deceptive interference.

[0062] In the present invention, in view of the characteristic that the interference-to-signal ratio of stronger short-delay deceptive interference is between 20dB and 40dB, a medium-intensity interference is virtualized in the signal direction of the satellite to be detected, so that the array antenna forms a null in the direction to suppress the satellite signal, thereby "highlighting" the deceptive interference, and then detecting whether there is deceptive interference and the satellite signal that the deceptive interference is intended to replace.

[0063] According to the present invention, by suppressing the satellite signal to be detected and highlighting the deception interference, judging whether there is strong short-delay deception interference includes:

[0064] Determine the visible satellite set according to the almanac and the approximate position, and select the satellites to be inspected from the visible satellite set in sequence;

[0065] A medium-intensity interference is created in the direction of the signal from the satellite to be detected, so that the array antenna forms a null in the direction to suppress the signal from the satellite to be detected;

[0066] According to whether the navigation processing unit can capture and track the satellite to be detected or the non-visible satellite, it is determined whether there is strong short-delay deception interference against the satellite to be detected or the non-visible satellite.

[0067] According to the present invention, the method of creating a virtual medium-intensity interference in the direction of the signal from the to-be-detected satellite so that the array antenna forms a null in the direction to suppress the signal from the to-be-detected satellite includes:

[0068] According to the position of the satellite to be inspected and the attitude of the antenna array, a vector matrix of the satellite to be inspected is obtained;

[0069] Solve the weight vector of the array antenna through the steering vector matrix;

[0070] By using the weight vector, the array antenna forms a null in the upward direction of the signal of the satellite to be detected to suppress the signal of the satellite to be detected;

[0071] The formula used to solve the weight vector of the array antenna through the steering vector matrix is:

[0072] ;

[0073] in, is the weight vector of the array antenna, is the guidance vector matrix for the satellite to be detected, is the constraint vector that the weight vector needs to satisfy. For adaptive zeroing and anti-interference, is a vector whose first element is non-zero.

[0074] According to the present invention, if there is deceptive interference, estimating its amplitude and phase, and recovering the deceptive interference includes:

[0075] If there is deceptive interference targeting at least one satellite, the input data will be divided into two paths, one is sent to the FIFO cache, and the other is sent to the tracking link. By capturing and tracking the satellite signal and the strong short-delay deceptive interference, the amplitude and phase of the deceptive interference are estimated, and the deceptive interference is restored in combination with the pseudo-random code of the targeted satellite signal.

[0076] According to the present invention, subtracting the recovered deceptive interference from the received signal to reduce the residual deceptive interference strength in the received signal to below -10 dB includes:

[0077] The recovered deception interference is subtracted from the FIFO buffer data, so as to effectively suppress the deception interference in the FIFO buffer data and reduce the residual deception interference intensity to below -10dB.

[0078] According to the present invention, a correlator is added to the PAC method, and the correlator is used to search ~ Correlation peaks in the chip area are used to correct the phase detection function to eliminate residual deception interference, including:

[0079] Based on the L1, L2, E1, and E2 correlators of the PAC method, add a search ~ A correlator for correlation peaks within a chip region;

[0080] According to the amplitude and relative delay of the correlation peak in the region, its influence on the original correlator output is determined;

[0081] Its influence is deducted in the PAC phase detection function to eliminate the negative impact of the correlation peak in this area, thereby eliminating the pseudo-code tracking error caused by residual deception interference.

[0082] According to the present invention, determining the influence of the correlation peak on the original correlator output according to the amplitude and relative delay of the correlation peak in the region includes:

[0083] If the correlation peak found is between ~ When , its correlation value with the pseudo-random code will be added to the output of the L2 correlator, and may also be added to the output of the L1 correlator. The additional value introduced by the deceptive interference must be deducted from the outputs of the L2 and L1 correlators;

[0084] If the correlation peak found is between ~ When the pseudo-random code is used, its correlation value with the pseudo-random code will be added to the L2, L1 correlator output and the satellite signal correlation peak amplitude, and may also be added to the E1 correlator output. The additional value introduced by the deceptive interference must be deducted from the L2, L1, E1 correlator output and the satellite signal correlation peak amplitude.

[0085] According to the present invention, deducting its influence in the PAC phase detection function, eliminating the negative influence of the correlation peak in the area, and then eliminating the pseudo code tracking error caused by the residual deception interference includes:

[0086] If the correlation peak found is between ~ When , the phase detection function expression of the PAC method is:

[0087] ;

[0088] in, and is the output of the I and Q channels of the E1 correlator, and is the output of the I and Q channels of the E2 correlator, and is the output of the I and Q channels of the L1 correlator, and is the output of the I and Q channels of the L2 correlator, and is the amplitude of the satellite signal correlation peak, The relative delay of the deceptive interference is between ~ When , the phase detection function expression of the PAC method.

[0089] In the phase detector function expression of the PAC method , , and The expressions are:

[0090]

[0091]

[0092]

[0093]

[0094] in, and To deceive the amplitude of the interference correlation peak, is the relative delay of the deceptive interference.

[0095] According to the present invention, deducting its influence in the PAC phase detection function, eliminating the negative influence of the correlation peak in the area, and then eliminating the pseudo code tracking error caused by the residual deception interference includes:

[0096] If the correlation peak found is between ~ When , the phase detection function expression of the PAC method is:

[0097] ;

[0098] in, The relative delay of the deceptive interference is between ~ When , the phase detection function expression of the PAC method;

[0099] In the phase detector function expression of the PAC method , , , , , , , , and The expressions are:

[0100]

[0101]

[0102]

[0103] ;

[0104]

[0105]

[0106]

[0107] ;

[0108]

[0109] .

[0110] In the present invention, aiming at the characteristics of the interference-to-signal ratio of stronger short-delay deceptive interference being between 20dB and 40dB and the delay being between 0.2 and 1.5 chips, the amplitude and phase of the deceptive interference are first estimated, and then the deceptive interference is restored; then the restored deceptive interference is subtracted from the received signal to suppress most of the deceptive interference in the received signal, so that the residual deceptive interference intensity is reduced to below -10dB; finally, an improved PAC method including 5 correlators is adopted to eliminate the residual deceptive interference, and the tracking error is 0 when the deceptive interference delay is between 0.2 and 1.2 chips, thereby systematically solving the problem of suppressing stronger short-delay deceptive interference.

[0111] The present invention will be described in more detail below by way of examples.

[0112] Embodiment 1:

[0113] like Figure 4 As shown, this embodiment proposes a relatively strong short-delay deception interference detection and suppression method for high-precision anti-interference navigation, including a deception interference detection method based on suppressing satellite signals and highlighting deception interference, and a deception interference suppression method based on "recovery first, then cancellation, and then phase discrimination":

[0114] The specific steps are as follows:

[0115] (1) Strong short-delay deception interference detection method:

[0116] A relatively strong short-delay deception interference detection method determines the visible satellite set according to the almanac, preliminary position, etc., and takes the satellites in the visible satellite set as the satellites to be detected; by virtualizing the medium-intensity interference upward on the signal of the satellite to be detected, the array antenna forms a null in the signal of the satellite to be detected to suppress the satellite signal; if the navigation processing unit can still capture and track the satellite to be detected or the satellite outside the visible satellite set, it is determined that there is deception interference against the satellite to be detected or the non-visible satellite;

[0117] Specifically, the suppression of the satellite signal to be detected is achieved as follows: according to the position of the satellite to be detected, the antenna array attitude, etc., the vector matrix of the satellite to be detected is obtained. ;according to Solve for the weight vector of the array antenna, where is the constraint vector that the weight vector needs to satisfy; for example, for adaptive zeroing (i.e., power inversion) anti-interference, is a vector whose only first element is non-zero;

[0118] The satellites to be inspected are distributed in space at an azimuth of 150 degrees and an elevation of 60 degrees. Figure 5 As shown; the array antenna directional pattern obtained by using the above-mentioned method to form a null upward in the satellite signal to be detected is as follows Figure 6 As shown;

[0119] Figure 6 It shows that the array antenna forms a null in the direction of the satellite to be detected (azimuth 150 degrees, elevation 60 degrees), and the gain at the null is as low as about -50dB, thereby effectively suppressing the signal of the satellite to be detected;

[0120] If the navigation processing unit can still capture and track the satellite to be detected or the satellite outside the visible satellite set, it is determined that there is deception interference against the satellite to be detected or the non-visible satellite;

[0121] (2) Strong short-delay deception interference suppression method:

[0122] The strong short-delay deception interference suppression method estimates the amplitude and phase of the deception interference by capturing and tracking "satellite signal + strong short-delay deception interference", recovers the deception interference with the pseudo-random code, and then subtracts it from the received signal to effectively suppress the deception interference, reducing the residual deception interference intensity to below -10dB; the new pseudo-code phase detector is mainly composed of 2 narrow correlators, 2 wide correlators, and 1 ~ The PAC phase-discrimination function is modified by using the correlation peak and position found by the fifth correlator to improve the pseudo-code phase-discrimination performance and ensure that the tracking error of short-delay deception interference is 0.

[0123] a) Deception jamming recovery and cancellation:

[0124] When the strong short-delay deception interference detection method determines that there is deception interference against certain satellites, it first divides the input data into two parts, one of which is sent to the first-in-first-out (FIFO) cache, and the other is sent to the tracking link to estimate the amplitude and phase of the deception interference; then, the deception interference is restored based on the amplitude and phase of the deception interference and the pseudo-random code of the targeted satellite signal; finally, the restored deception interference is subtracted from the cached data to suppress most of the deception interference;

[0125] When the interference-to-signal ratio of the deceptive interference is 20dB and 40dB respectively, the correlation results after deceptive interference recovery and cancellation are as follows: Figure 7 As shown in the left and right figures;

[0126] Figure 7 It shows that when the interference-to-signal ratio is 20dB, the correlation peak at the real pseudo code delay and Doppler frequency 2kHz is very prominent, and the main peak amplitude has an overwhelming advantage; the correlation peak at the deception interference delay and Doppler frequency -2kHz has been cancelled; when the interference-to-signal ratio is 40dB, the correlation peak at the real pseudo code delay and Doppler frequency 2kHz is still prominent; the correlation peak at the deception interference delay and Doppler frequency -2kHz has a certain residual, which is suppressed by the subsequent improved PAC phase detector;

[0127] b) Residual deception interference suppression:

[0128] In view of the shortcomings of the PAC method, the improved PAC method adds a search function based on the original four correlators. ~ The correlator of the correlation peak in the chip area calculates its influence on the original correlator output according to the amplitude and relative delay of the correlation peak in the area, and deducts its influence in the PAC phase detection function to eliminate the negative influence of the correlation peak in the area, thereby eliminating the pseudo code tracking error caused by the residual deception interference;

[0129] The relative delay of deception interference is between ~ When the relative delay of the deceptive interference is between ~ When , its correlation value with the pseudo-random code will be added to the output of the L2 correlator, and may also be added to the output of the L1 correlator, such as Figure 8 As shown; therefore, the correlation values ​​added by the deceptive interference should be deducted from these correlator outputs;

[0130] When the relative delay of deception interference is between ~ When , its correlation value with the pseudo-random code will be added to the output of the L2 and L1 correlators and the amplitude of the satellite signal correlation peak, and may also be added to the output of the E1 correlator, such as Fig. 9 As shown; therefore, the correlation values ​​added by the deceptive interference should be deducted from these correlator outputs;

[0131] When the fifth correlator is ~ When the correlation peak is found in the chip area, the relative delay of the deception interference is between ~ When , the phase detection function of the improved PAC method is divided into two sections;

[0132] When the relative delay of the deceptive interference is between ~ When , the phase detection function of the improved PAC method is:

[0133] ;

[0134] in, and is the output of the I and Q channels of the E1 correlator, and It is the output of I and Q channels of E2 correlator; and is the output of the I and Q channels of the L1 correlator, and is the output of the I and Q channels of the L2 correlator; and is the amplitude of the satellite signal correlation peak;

[0135]

[0136]

[0137]

[0138]

[0139] in, and To deceive the amplitude of the interference correlation peak, The relative delay of the deceptive jammer;

[0140] When the relative delay of the deceptive interference is between ~ When , the phase detection function of the improved PAC method is:

[0141] ;

[0142] In the formula,

[0143]

[0144]

[0145]

[0146] ;

[0147]

[0148]

[0149]

[0150] ;

[0151]

[0152] ;

[0153] exist When the value is 0.2, the relationship between the pseudo-code tracking error of the improved PAC method and the relative delay of the residual deception interference is as follows: Fig.10 As shown;

[0154] Will Fig.10 and Figure 3 By comparison, it can be seen that the improved PAC method avoids the shortcomings of the PAC method - when the deception interference delay is between 0.8 and 1.2 code chips, the pseudo-code tracking error is large; the improved PAC method can eliminate the residual deception interference with a delay between 0.2 and 1.5 code chips.

[0155] The embodiment of the present invention proposes a method for detecting and suppressing strong short-delay deception interference for high-precision anti-interference navigation. The method adopts the detection idea of ​​suppressing satellite signals and highlighting deception interference. It can detect whether there is deception interference and the satellite signal that the deception interference is intended to replace, and guide the subsequent deception interference suppression. It also adopts the suppression idea of ​​first recovering, then canceling, and then phase detection, combining the deception interference recovery and cancellation method with the improved PAC method, thereby systematically solving the problem of suppressing strong short-delay deception interference.

[0156] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for detecting and suppressing strong short-delay deception interference for high-precision anti-interference navigation, characterized in that: include: By suppressing the signal of the satellite to be detected and highlighting the deception interference, it is determined whether there is strong short-delay deception interference; If the deceptive interference exists, estimating its amplitude and phase, and restoring the deceptive interference; Subtracting the recovered deceptive interference from the received signal to reduce the residual deceptive interference intensity in the received signal to below -10 dB; In the PAC method, a correlator is added and used to search for ~ Correlation peaks in the chip region are used to correct the phase detection function to eliminate the residual deception interference; By suppressing the signal of the satellite to be detected and highlighting the deception interference, it is judged whether there is strong short-delay deception interference, including: Determine a visible satellite set according to the almanac and the approximate position, and select satellites to be inspected from the visible satellite set in sequence; A virtual medium-intensity interference is applied in the direction of the signal of the satellite to be detected, so that the array antenna forms a null in the direction to suppress the signal of the satellite to be detected; According to whether the navigation processing unit can capture and track the satellite to be detected or the non-visible satellite, it is determined whether there is strong short-delay deception interference against the satellite to be detected or the non-visible satellite; In the PAC method, a correlator is added and used to search for ~ Correlation peaks in the chip region, and using the correlation peaks to correct the phase detection function, and eliminating the residual deception interference includes: Based on the L1, L2, E1, and E2 correlators of the PAC method, add a search ~ A correlator for correlation peaks within a chip region; Determine the influence of the correlation peak on the original correlator output according to the amplitude and relative delay of the correlation peak in the region; Its influence is deducted in the PAC phase detection function to eliminate the negative influence of the correlation peak in this area, thereby eliminating the pseudo-code tracking error caused by the residual deception interference.

2. The method according to claim 1, characterized in that Creating a virtual medium-intensity interference in the direction of the signal from the satellite to be detected, so that the array antenna forms a null in the direction to suppress the signal from the satellite to be detected, comprises: According to the position of the satellite to be inspected and the attitude of the antenna array, a vector matrix of the satellite to be inspected is obtained; By using the steering vector matrix, solving the weight vector of the array antenna; By using the weight vector, the array antenna forms a null upward when the signal of the satellite to be detected comes so as to suppress the signal of the satellite to be detected; The formula used to solve the weight vector of the array antenna through the steering vector matrix is: ； in, is the weight vector of the array antenna, is the guidance vector matrix for the satellite to be detected, is the constraint vector that the weight vector needs to satisfy. For adaptive zeroing and anti-interference, is a vector whose first element is non-zero.

3. The method according to claim 1, characterized in that If the deceptive interference exists, estimating its amplitude and phase, and recovering the deceptive interference includes: If there is deceptive interference targeting at least one satellite, the input data will be divided into two paths, one is sent to the FIFO cache, and the other is sent to the tracking link. By capturing and tracking the satellite signal and the strong short-delay deceptive interference, the amplitude and phase of the deceptive interference are estimated, and the deceptive interference is restored in combination with the pseudo-random code of the targeted satellite signal.

4. The method according to claim 1, characterized in that Subtracting the recovered deceptive interference from the received signal to reduce the residual deceptive interference strength in the received signal to below -10 dB comprises: The recovered deceptive interference is subtracted from the FIFO buffer data, thereby effectively suppressing the deceptive interference in the FIFO buffer data and reducing the residual deceptive interference intensity therein to below -10 dB.

5. The method according to claim 1, characterized in that Determining the influence of the correlation peak on the original correlator output according to the amplitude and relative delay of the correlation peak in the region includes: If the correlation peak found is between ~ When the correlation value between the pseudo-random code and the pseudo-random code is added to the output of the L2 correlator, and may also be added to the output of the L1 correlator, the additional value introduced by the deceptive interference must be deducted from the outputs of the L2 and L1 correlators; If the correlation peak found is between ~ When the pseudo-random code is used, its correlation value with the pseudo-random code will be added to the L2, L1 correlator outputs and the satellite signal correlation peak amplitude, and may also be added to the output of the E1 correlator. The additional value introduced by the deceptive interference must be deducted from the L2, L1, E1 correlator outputs and the satellite signal correlation peak amplitude.

6. The method according to claim 1, characterized in that The method of deducting the influence of the correlation peak in the PAC phase detection function to eliminate the negative influence of the correlation peak in the region and thereby eliminate the pseudo-code tracking error caused by the residual deception interference includes: if the searched correlation peak, i.e., the relative delay of the deception interference, is between ~ When , the phase discrimination function expression of the PAC method is: ； in, and is the output of the I and Q channels of the E1 correlator, and is the output of the I and Q channels of the E2 correlator, and is the output of the I and Q channels of the L1 correlator, and is the output of the I and Q channels of the L2 correlator, and is the amplitude of the satellite signal correlation peak, The relative delay of the deceptive interference is between ~ When the phase-discrimination function expression of the PAC method is: , , and The expressions are: in, and To deceive the amplitude of the interference correlation peak, is the relative delay of the deceptive interference.

7. The method according to claim 1, characterized in that The method of deducting the influence of the correlation peak in the PAC phase detection function to eliminate the negative influence of the correlation peak in the region and thereby eliminate the pseudo-code tracking error caused by the residual deception interference includes: if the searched correlation peak, i.e., the relative delay of the deception interference, is between ~ When , the phase discrimination function expression of the PAC method is: in, The relative delay of the deceptive interference is between ~ When the phase-discrimination function expression of the PAC method is: , , , , , , , , and The expressions are:

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