Method and apparatus for generating spoofing interference against authorized users

Abstract

The present application provides a method and device for generating spoofing interference for authorized users. Among them, the planar array antenna is composed of microstrip patch antennas with small volume and low cost arranged in a plane according to a set rule. It neither needs to divide the sub-spatial domain or sub-spherical surface in advance, nor does it need to specially design the coverage area of the planar array antenna. Therefore, it is significantly superior to the existing methods in terms of volume, cost, power consumption, and deployment. During the process of satellite navigation signal purification, the obtained optimal weight vector is the optimal weight vector in the sense of minimum variance distortionless response. On the one hand, it has strong amplitude and phase compensation capabilities, so the requirements for the amplitude and phase of the RF channel are significantly reduced compared with the existing methods, which is conducive to engineering implementation. On the other hand, in the presence of external interference and transceiver mutual interference, the array antenna pattern forms a depression in the direction of the interference with dominant power, thereby avoiding the influence of interference and mutual interference on satellite navigation signal purification.

Description

Technical Field

[0001] The present application relates to a method and device for generating spoofing interference for authorized users, belonging to the technical field of satellite navigation. Background Art

[0002] Satellite navigation signals are divided into public signals and authorized signals. Although both adopt the direct sequence spread spectrum (DSSS) system, the public signals use short-period spreading codes, and the spreading code structure and parameters are published in the interface control document (ICD) of the space signal of each global navigation satellite system (GNSS); the authorized signals use aperiodic spreading codes, and the spreading code scheme is not public and can only be generated by a dedicated authorized chip with multiple security protection measures, which eliminates regenerative spoofing interference at the source - spoofing interference generated based on the spreading code structure and parameters, navigation message, carrier frequency, etc.

[0003] Users who pass the detection and management procedures such as network access permission, network access registration, and authorized refueling update - authorized users, use the spreading code generated by the local dedicated authorized chip to perform correlation despreading on the received satellite navigation signal, and then can enjoy services exclusive to the authorized signal such as anti-regenerative spoofing interference and controllable spot beam power enhancement through demodulation and calculation processing.

[0004] Therefore, spoofing interference against authorized users can only adopt repeater spoofing interference. For the generation of repeater spoofing interference, first, the navigation signals broadcast by visible satellites with an elevation angle of more than 5 degrees need to be purified to obtain each satellite navigation signal respectively; then, according to the spoofing strategy, adjust the time delay, Doppler frequency shift, power magnitude, etc. of each satellite navigation signal to form corresponding spoofing interference; finally, determine the spatial deployment of the transmitting unit according to the spoofing strategy to ensure that each spoofing interference is incident on the target authorized user to be spoofed according to the preset strategy. Among them, satellite navigation signal purification is the premise and key for the generation of repeater spoofing interference.

[0005] There are mainly two existing methods for satellite navigation signal purification: 1) The purification method based on multiple parabolic antennas and servo systems has a simple mechanism of action, but it is difficult to implement due to the large volume, high cost, high power consumption, and difficult deployment of the parabolic antennas and servo systems. 2) The purification method based on multi-faceted array antennas and multi-channel navigation processing units has improved in terms of volume, cost, power consumption, and deployment compared with method 1), but the number of channels of the directional antennas and navigation processing units is large, and there are high requirements for the amplitude-phase characteristics within the channels and the amplitude-phase consistency between channels, making it difficult to achieve in engineering. Summary of the Invention

[0006] The present application provides a method and device for generating spoofing interference for authorized users to solve the problems existing in the existing satellite navigation signal purification methods, such as large volume, high cost, high power consumption, difficult deployment, and harsh amplitude-phase requirements.

[0007] In a first aspect, an embodiment of the present application provides a method for generating spoofing interference for authorized users, including:

[0008] Obtain q channels of analog radio frequency signals collected by a planar array antenna; the planar array antenna includes q microstrip patch antennas arranged in a planar array according to a set rule; all q microstrip patch antennas are used to receive radio frequency signals in a hemispherical airspace to obtain q channels of analog radio frequency signals;

[0009] Process the q channels of analog radio frequency signals to obtain q channels of analog intermediate frequency signals, and convert the q channels of analog intermediate frequency signals into q channels of digital intermediate frequency signals;

[0010] Obtain the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite;

[0011] Based on the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the j-th satellite, calculate the optimal weight vector w of the q channels of digital intermediate frequency signals under the minimum variance distortionless response (MVDR) criterion j , j = 1, 2,..., i, where i is the number of all visible satellites in the hemispherical airspace;

[0012] Based on the i optimal weight vectors w j Perform weighted calculations on the q channels of digital intermediate frequency signals respectively to obtain i channels of satellite navigation digital intermediate frequency signals;

[0013] Process the i channels of satellite navigation digital intermediate frequency signals according to a set spoofing strategy to obtain i channels of spoofing interference digital intermediate frequency signals;

[0014] Convert the i channels of spoofing interference digital intermediate frequency signals into i channels of spoofing interference analog radio frequency signals, and transmit the specified spoofing interference analog radio frequency signals to the target authorized user to be spoofed according to the spoofing strategy.

[0015] Based on the above method, optionally, the method of calculating the weight vector that minimizes the output variance of the planar array antenna under the gain constraint in the direction of the j-th satellite signal based on the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the j-th satellite includes:

[0016] Based on the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite, calculate the incident directions of the i satellite signals in the array antenna coordinate system;

[0017] Based on the incident directions and the position vectors of the microstrip patch antennas in the array antenna coordinate system, calculate the steering vectors of the i satellite signals in the array antenna coordinate system;

[0018] Based on the i steering vectors, calculate the weighted vector that minimizes the output variance of the planar array antenna under the gain constraint in the direction of arrival of the j-th satellite signal, that is, the optimal weighted vector w j .

[0019] Based on the above method, optionally, the calculating the weighted vector that minimizes the output variance of the planar array antenna under the gain constraint in the direction of arrival of the j-th satellite signal based on the i steering vectors includes:

[0020] Solve it using the sampling correlation matrix inversion algorithm, the recursive least squares method, or the QR decomposition-recursive least squares method;

[0021] Alternatively, after reducing the rank using the multistage nested Wiener filtering algorithm, perform iterative solution.

[0022] Based on the above method, optionally, the obtaining the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite includes:

[0023] Measure the attitude of the planar array antenna through an attitude sensor fixedly connected to the array antenna and with the sensitive axis coinciding with the coordinate axis of the array antenna coordinate system, or estimate the attitude of the planar array antenna by the planar array antenna itself;

[0024] Determine the approximate position of the phase center of the planar array antenna as the phase center position of the planar array antenna through historical data, and determine the approximate position of the satellite as the position of the satellite through historical data; or, suppress interference through null control, capture and track the satellite navigation public signal, demodulate the navigation message to obtain the position of the satellite, and perform position, velocity, time (PVT) solution to obtain the phase center position of the planar array antenna.

[0025] In a second aspect, an embodiment of the present application further provides a spoofing interference generation device for authorized users, which includes:

[0026] A planar array antenna, a radio frequency channel, a beamforming unit, a spoofing interference forming unit, and a spoofing interference transmitting unit;

[0027] The planar array antenna includes q microstrip patch antennas arranged in a planar array according to a set rule; the q microstrip patch antennas are all used to receive radio frequency signals in the hemispherical airspace and obtain q channels of analog radio frequency signals;

[0028] The radio frequency channel includes q channels, each channel corresponding to one of the microstrip patch antennas. The radio frequency channel is used to process the q channels of analog radio frequency signals output by the q microstrip patch antennas through the q channels respectively to obtain q channels of analog intermediate frequency signals;

[0029] The beamforming unit includes an analog-to-digital converter, an attitude and position determination module, an antenna weight vector calculation module, and a multi-beam pointing formation module; the analog-to-digital converter is used to convert q channels of analog intermediate-frequency signals into q channels of digital intermediate-frequency signals; the attitude and position determination module is used to determine the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite; the antenna weight vector calculation module is used to calculate the optimal weighting vector w for the q channels of digital intermediate-frequency signals under the MVDR criterion according to the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the j-th satellite j , j = 1, 2,..., i, where i is the number of all visible satellites in the hemispherical airspace; the multi-beam pointing formation module is used to perform weighted calculations on the q channels of digital intermediate-frequency signals based on the i optimal weighting vectors w j respectively to obtain i channels of satellite navigation digital intermediate-frequency signals;

[0030] The spoofing interference formation unit is used to process the i channels of satellite navigation digital intermediate-frequency signals according to a set spoofing strategy to obtain i channels of spoofing interference digital intermediate-frequency signals;

[0031] The spoofing interference transmitting unit is used to convert the i channels of spoofing interference digital intermediate-frequency signals into i channels of spoofing interference analog radio frequency signals and transmit the specified spoofing interference analog radio frequency signals to the target authorized user to be spoofed according to the spoofing strategy.

[0032] Based on the above device, optionally, in the planar array antenna, the q microstrip patch antennas are arranged in a regular polygon or a circle, and the spacing between adjacent microstrip patch antennas does not exceed half of the wavelength of the satellite navigation signal carrier.

[0033] Based on the above device, optionally, the spoofing interference formation unit includes an electro-optical converter, and the electro-optical converter is used to convert the i channels of spoofing interference digital intermediate-frequency signals into 1 channel of high-speed serial signal;

[0034] The spoofing interference formation unit is connected to the spoofing interference transmitting unit through an optical cable, and the optical cable is used to transmit the 1 channel of high-speed serial signal converted by the electro-optical converter to the spoofing interference transmitting unit.

[0035] Based on the above device, optionally, the spoofing interference transmitting unit includes an opto-electrical converter, and the opto-electrical converter is used to convert the received 1 channel of high-speed serial signal into i channels of spoofing interference digital intermediate-frequency signals and then process and transmit them.

[0036] The above technical solution provided by this application has at least the following beneficial effects:

[0037] In the spoofing interference generation method and device for authorized users provided by the present application, the planar array antenna is composed of microstrip patch antennas arranged in a plane according to a set rule, with small volume and low cost. It neither needs to pre-divide the sub-spatial domain or sub-spherical surface in advance, nor does it need to specially design the coverage area of the planar array antenna. Therefore, it has advantages over the existing methods in terms of volume, cost, power consumption, and deployment. In addition, during the satellite navigation signal purification process, the obtained optimal weight vector is the optimal weight vector in the sense of MVDR, with strong amplitude-phase compensation ability. Therefore, the requirements for the amplitude and phase of the RF channel are significantly reduced compared with the existing methods, which is conducive to engineering implementation. In addition, since the optimal weight vector is the optimal weight vector in the sense of MVDR, for satellite navigation applications, because the interference is stronger than the noise and satellite signals, in order to minimize the output variance, the array antenna pattern must form a depression in the direction of the interference with dominant power. Therefore, satellite navigation signal purification can be completed in an external interference and transceiver mutual interference environment. Description of the Drawings

[0038] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application. In addition, these drawings and the written description are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments.

[0039] Figure 1 It is a schematic structural diagram of a spoofing interference generation device for authorized users provided by an embodiment of the present application;

[0040] Figure 2 It is a schematic flow diagram of a spoofing interference generation method for authorized users provided by an embodiment of the present application. Detailed Embodiments

[0041] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0042] As described in the background art section, satellite navigation signal purification is the premise and key for the generation of transponder spoofing interference.

[0043] There are mainly two existing satellite navigation signal purification methods:

[0044] 1) A purification method based on multiple parabolic antennas and a servo system. In this method, the hemispherical airspace is divided into k regions, and the k parabolic antennas perform beam scanning coverage on the assigned regions under the control of the servo system; by using the narrow beam and high gain characteristics of the parabolic antennas, the navigation signals broadcast by one satellite in each region are received; by using the complementarity of the beam scanning regions of the multiple parabolic antennas, the navigation signals broadcast by k visible satellites in the hemispherical airspace are respectively received to complete the purification of the satellite navigation signals in the hemispherical airspace. The mechanism of this method is simple, but it is difficult to implement due to the large volume, high cost, high power consumption, and difficult deployment of the parabolic antennas and the servo system.

[0045] 2) A purification method based on a multi-faceted array antenna and a multi-channel navigation processing unit. In this method, the hemispherical airspace is evenly divided into n sub-spherical surfaces along the meridians. In each sub-spherical surface, x rows and m columns of high-gain directional antennas are installed. The beam of each high-gain antenna covers a sub-airspace corresponding to the sub-spherical surface and is responsible for receiving the navigation signals broadcast by all visible satellites in the sub-region; the low-noise amplifier channels and forwarding processing modules connected to the back of each antenna respectively amplify, filter, down-convert, and sample the navigation signals; the civil code acquisition and tracking module captures and tracks the digital intermediate-frequency signals to obtain observables such as satellite numbers; the civil code-guided military code purification module extracts the navigation authorization signals of each satellite based on the observable data. This method has some improvements in terms of volume, cost, power consumption, and deployment compared to method 1), but the number of directional antennas and navigation processing unit channels is as high as nxm, and there are high requirements for the amplitude-phase characteristics within the channels and the amplitude-phase consistency between the channels, making it difficult to implement in engineering.

[0046] To solve the above problems, the present application provides a spoofing interference generation scheme for authorized users. Among them, digital beamforming technology is used to control the radiation pattern of the planar array antenna, adaptively form receiving beams respectively pointing to each satellite, parallelly complete the purification of the satellite navigation signals in the hemispherical airspace, and then generate spoofing interference signals according to the spoofing strategy. The following provides non-limiting descriptions of the specific implementation solutions through several examples or embodiments.

[0047] First, some embodiments of the present application provide a spoofing interference generation device for authorized users. Based on this device, the generation of spoofing interference for authorized users can be realized.

[0048] Refer to Figure 1 , Figure 1 which is a schematic structural diagram of a spoofing interference generation device for authorized users provided in the embodiments of the present application. As Figure 1 shown, the spoofing interference generation device for authorized users in this embodiment includes: a planar array antenna, a radio frequency channel, a beamforming unit, a spoofing interference forming unit, and a spoofing interference transmitting unit.

[0049] The specific structures and functions of the above - mentioned components are as follows:

[0050] 1) Planar array antenna

[0051] The planar array antenna includes q microstrip patch antennas arranged in a planar pattern according to a set rule; the q microstrip patch antennas are all used to receive radio - frequency signals in the hemispherical airspace and obtain q channels of analog radio - frequency signals.

[0052] The microstrip patch antenna has the advantages of small volume, light weight, low profile, and low cost. Therefore, in the solution of this embodiment, the microstrip patch antenna is selected to form the planar array antenna.

[0053] Moreover, in this solution, the structure of the planar array antenna is very simple. It is formed by arranging q microstrip patch antennas in a planar pattern according to a set rule without forming a parabolic or polyhedral structure; each antenna receives the navigation signals transmitted by all visible satellites in the hemispherical airspace without the need for special design of the coverage area of each microstrip patch antenna. Therefore, the deployment is simple and efficient.

[0054] Furthermore, the planar arrangement of the q microstrip patch antennas of the planar array antenna can be, but is not limited to, arranged in a regular polygon or a circle. And preferably, the spacing between adjacent microstrip patch antennas does not exceed half of the wavelength of the satellite navigation signal carrier, so that the grating lobe problem can be effectively avoided.

[0055] The planar array antenna includes q microstrip patch antennas, and each microstrip patch antenna can output one channel of analog radio - frequency signal. Therefore, the planar array antenna can output q channels of analog radio - frequency signals in total.

[0056] Among them, the value of q depends on the actual installation conditions and generally can range from more than a dozen to dozens.

[0057] 2) Radio - frequency channel

[0058] The radio - frequency channel includes q channels, and each channel corresponds to a microstrip patch antenna. The radio - frequency channel is used to process the q channels of analog radio - frequency signals output by the q microstrip patch antennas through the q channels respectively to obtain q channels of analog intermediate - frequency signals.

[0059] The radio - frequency channel is used to process the q channels of analog radio - frequency signals output by the planar array antenna. Each channel is used to process one channel of analog radio - frequency signal and finally outputs q channels of analog intermediate - frequency signals.

[0060] Furthermore, each radio - frequency channel is cascaded by devices such as an amplifier, a band - pass filter, and a down - converter to realize the amplification, filtering, and down - conversion processing of the input analog radio - frequency signal, so as to obtain the analog intermediate - frequency signal that meets the requirements. This part is the same as or similar to the existing satellite navigation signal purification method, so the specific implementation process will not be elaborated here.

[0061] In practice, the RF channel can be composed of discrete components such as amplifiers, filters, and downconverters, or can use integrated components that integrate functions such as amplification, filtering, and downconversion.

[0062] 3) Beamforming unit

[0063] The beamforming unit is the most core part of the solution in this embodiment, and is used to process the analog intermediate frequency signals output by the RF channel, and finally obtain i satellite navigation signals corresponding to i visible satellites in the hemispherical airspace in parallel. Among them, in the case of a masking angle of 5°, the number of visible satellites of a single GNSS in most regions of the world is 8-12, so i usually takes 8-12.

[0064] The beamforming unit includes an analog-to-digital converter, an attitude and position determination module, an antenna weight vector calculation module, and a multi-beam pointing formation module; the analog-to-digital converter is used to convert q analog intermediate frequency signals into q digital intermediate frequency signals; the attitude and position determination module is used to determine the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite; the antenna weight vector calculation module is used to calculate, according to the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the jth satellite, the weighted vector that minimizes the output variance of the planar array antenna under the gain constraint in the direction of the jth satellite signal, that is, the optimal weighted vector w of the q digital intermediate frequency signals under the MVDR (Minimum Variance Distortionless Response) criterion j (j = 1, 2,..., i); the multi-beam pointing formation module is used to perform weighted calculations on the q digital intermediate frequency signals respectively based on i optimal weighted vectors w j to obtain i satellite navigation digital intermediate frequency signals.

[0065] Among them, since subsequent processing needs to be carried out on digital signals, the beamforming unit first uses the analog-to-digital converter to convert q analog intermediate frequency signals into q digital intermediate frequency signals.

[0066] In addition, in order to calculate the satellite navigation digital intermediate frequency signals of each path, it is also necessary to determine the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite through the attitude and position determination module, and these data are used as calculation parameters to participate in the calculation. Among them, the phase center position of the planar array antenna and the position of the satellite refer to the positions in the protocol geocentric rectangular coordinate system.

[0067] Regarding the determination methods of the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite, they can be realized by means of measurement or estimation.

[0068] Among them, for the attitude of the planar array antenna, in practice, the planar array antenna can be fixedly installed relative to the ground, or can be installed on a moving carrier (such as a vehicle). For the fixed installation method, after the planar array antenna is installed, its attitude is fixed, so only one attitude measurement is required to directly obtain it during each subsequent use; while for the installation method on a moving carrier, the attitude of the planar array antenna needs to be obtained during each use.

[0069] Specifically, in practice, the attitude of the planar array antenna can be measured by an attitude sensor fixedly connected to the array antenna and with the sensitive axis coinciding with the coordinate axes of the AACS (Array Antenna Coordinate System); or the attitude of the planar array antenna can also be estimated autonomously by the planar array antenna. The latter method is mainly for the installation method on a moving carrier and can be determined according to the previous attitude of the planar array antenna and the movement of the moving carrier.

[0070] For the phase center position of the planar array antenna and the position of the satellite, either the rough positions of the phase center of the planar array antenna and the satellite can be used; or interference can be suppressed through null control, the public signal of satellite navigation can be captured and tracked, the navigation message can be demodulated to obtain the satellite position, and PVT (Position, Velocity, Time) can be solved to obtain the phase center position of the planar array antenna. This method can obtain more accurate position information.

[0071] Specifically, for the phase center position of the planar array antenna, the rough position of the phase center of the planar array antenna can be determined through historical data, and the rough position of the satellite can be determined through historical data. Among them, when the planar array antenna is fixedly installed relative to the ground or the moving carrier hardly moves, the previous PVT solution data can be used as the rough position of the phase center this time. For the position of the satellite, the rough position of the satellite can be obtained by querying the almanac of satellite navigation.

[0072] When more accurate position information is required, interference can be suppressed through null control, the public signal of satellite navigation can be captured and tracked, the navigation message can be demodulated to obtain the satellite position, and PVT solution can be performed to obtain the phase center position of the planar array antenna. Among them, this method is an existing technology, so the specific calculation process will not be elaborated.

[0073] After obtaining parameters such as the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the j-th satellite through the attitude and position determination module, the antenna weight vector calculation module is responsible for further calculating the optimal weight vector w of the q-channel digital intermediate frequency signal under the MVDR criterion j (j = 1, 2,..., i).

[0074] MVDR (Minimum Variance Distortionless Response) is a design criterion used to optimize array antenna systems. Its goal is to minimize the variance of the array antenna output while satisfying the gain constraint in the specified satellite signal arrival direction. Since the optimal weight vector obtained in the embodiments of this solution is the optimal weight vector in the sense of MVDR, it has a strong amplitude and phase compensation ability. Therefore, the amplitude and phase requirements for the RF channels are significantly reduced compared to existing methods, which is conducive to engineering implementation. At the same time, for satellite navigation applications, the interference is stronger than the noise and satellite signals. To minimize the output variance, the array antenna pattern must form a depression in the direction of the interference with dominant power. Therefore, this solution can purify satellite navigation signals in an environment of external interference and transceiver mutual interference.

[0075] Furthermore, the antenna weight vector calculation module calculates the optimal weight vector w for the q-channel digital intermediate frequency signals under the MVDR criterion based on the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the j-th satellite j (j = 1, 2,..., i), and the specific steps include:

[0076] (1) Based on the attitude of the planar array antenna (ε X , ε Y , ε Z ), the phase center position of the planar array antenna (x p , y p , z p ) and the position of the j-th satellite calculate the arrival direction of the j-th satellite signal in the array antenna coordinate system (AACS)

[0077] Specifically, the calculation of the azimuth angle and elevation angle θ j of the satellite signal in AACS can be obtained through the transformation of the satellite observation vector at the phase center P point of the array antenna among the protocol geocentric rectangular coordinate system, the local coordinate system (i.e., the northeast celestial coordinate system), and the array antenna coordinate system AACS. The detailed process is as follows:

[0078] Transform the observation vector of the k-th satellite at point P in the protocol geocentric rectangular coordinate system to the observation vector (Δu, Δv, Δe) in AACS through two rotation transformations. The transformation relationship is:

[0079]

[0080] where the coordinate transformation matrix R EA and REE The expressions are as follows:

[0081] R EA = R(ε X )R(ε Y )R(ε Z )

[0082]

[0083]

[0084] where λ = arctan(y p / x p ) and φ are the longitude and latitude of point P in the geocentric rectangular coordinate system of the protocol, respectively. The latitude φ is obtained by iterating 3 to 4 times according to the following formula, and its initial value is taken as 0.

[0085]

[0086] Among them, the constant a is the semi-major axis of the reference ellipsoid of the earth, and the constant e is the eccentricity of the reference ellipsoid.

[0087] Furthermore, the direction of the incoming wave can be obtained from Δu, Δv, and Δe. The azimuth angle of the incoming wave and the elevation angle θ j are as follows:

[0088]

[0089] (2) Based on the direction of the incoming wave and the position vectors of each microstrip patch antenna in the array antenna coordinate system, the steering vector of the jth satellite signal in the array antenna coordinate system is calculated.

[0090] The steering vector is determined by the inner product of the unit vector in the direction of the incoming wave and the position vectors [b l ; l = 1, 2,..., q] of each antenna in the AACS.

[0091] Among them, T is the vector transpose symbol, f is the carrier frequency, and c is the speed of light; the antenna position vector b l is determined by the layout of the array antenna and is a constant vector after the layout of the array antenna is determined.

[0092] (3) Based on the i steering vectors, the weighted vector that minimizes the output variance of the planar array antenna under the gain constraints of i satellites is calculated, that is, the optimal weighted vector.

[0093] The optimal weighted vector w jis a q - dimensional column vector, j = 1, 2, ..., i. w j is the optimal solution that minimizes the output variance of the planar array antenna under the gain constraint (gain is 1) of the incoming direction of the \(j\)th satellite signal. It is expressed by the formula:

[0094]

[0095] In the formula, \(H\) is the symbol of vector conjugate transpose, is for the output \(r=[r 1 , r 2 ,..., r q T which is the output variance after weighted summation. The optimal weighted vector is optimal in the sense of MVDR, and thus has a strong amplitude - phase compensation ability.

[0096] Through the above method, the required optimal weighted vector \(w j can be obtained.

[0097] Among them, the calculation method in step (3) above is essentially an optimization problem under certain constraints. For this optimization problem, current optimization algorithms can be used to solve it. For example, it can be solved by the sampling correlation matrix inversion algorithm (SMI), the recursive least - squares method (RLS), the orthogonal triangular decomposition - recursive least - squares method (QR - RLS), etc.; it can also be solved by first reducing the rank through the multistage nested Wiener filtering algorithm (MSNWF) and then iteratively solving. Appropriate algorithms can be selected according to actual needs, and will not be elaborated here.

[0098] After obtaining the optimal weighted vector \(w j , the multi - beam pointing formation module is responsible for using \(i\) optimal weighted vectors \(w j to weight the \(q\) - path digital intermediate - frequency signals respectively, and obtain \(i\) - path satellite navigation digital intermediate - frequency signals.

[0099] According to actual needs, the digital intermediate - frequency signals corresponding to each satellite can be calculated, or only the digital intermediate - frequency signals corresponding to some of the satellites can be obtained.

[0100] 4) Deception interference formation unit

[0101] The deception interference formation unit is used to process the \(i\) - path satellite navigation digital intermediate - frequency signals according to the set deception strategy to obtain \(i\) - path deception interference digital intermediate - frequency signals.

[0102] Specifically, the deception interference formation unit adjusts the time delay, Doppler frequency shift, power magnitude, etc. of each path of satellite navigation signals according to the deception strategy to obtain \(i\) - path deception interference digital intermediate - frequency signals. This part is the same as or similar to the existing method for forming deception interference digital intermediate - frequency signals, so the specific implementation process will not be elaborated. ​

[0103] In some embodiments, the spoofing jamming forming unit may include an electro-optical converter, which is configured to convert the i-channel spoofing jamming digital intermediate frequency signal into a 1-channel high-speed serial signal. The spoofing jamming forming unit and the spoofing jamming transmitting unit are connected by an optical cable, and the optical cable is used to transmit the 1-channel high-speed serial signal converted by the electro-optical converter to the spoofing jamming transmitting unit.

[0104] Although the solution of the present application can purify the satellite navigation signal in an environment of external interference and transceiver mutual interference (i.e., the interference of the spoofing jamming transmission on the satellite navigation signal reception), it is indeed possible to relieve the pressure of transceiver mutual interference by separating the spoofing jamming transmitting unit from the unit receiving the satellite navigation signal.

[0105] For application scenarios where the transmission of spoofing jamming and the reception of satellite navigation signals are allowed to be far apart, if the i-channel spoofing jamming digital intermediate frequency signal is directly sent to the spoofing jamming transmitting unit through a cable, a large loss problem will be faced. To solve this problem, in this embodiment, the spoofing jamming forming unit may include an electro-optical converter, which converts the i-channel low-speed spoofing jamming digital intermediate frequency signal into a 1-channel high-speed serial signal and then transmits it to the spoofing jamming transmitting unit through an optical cable for transmission, thereby effectively reducing the transmission loss.

[0106] For application scenarios where the transmission of spoofing jamming and the reception of satellite navigation signals can only be at the same location, since there is no need for long-distance transmission of the spoofing jamming digital intermediate frequency signal, the electro-optical converter may not be included in the spoofing jamming forming unit.

[0107] 5) Spoofing jamming transmitting unit

[0108] The spoofing jamming transmitting unit is configured to convert the i-channel spoofing jamming digital intermediate frequency signal into an i-channel spoofing jamming analog radio frequency signal and transmit the specified spoofing jamming analog radio frequency signal to the target authorized user to be spoofed according to the spoofing strategy.

[0109] Specifically, the spoofing jamming transmitting unit mainly consists of a digital-to-analog converter, an upconverter, a power amplifier, a filter, a transmitting antenna, etc.

[0110] The digital-to-analog converter and the upconverter sequentially convert the i-channel spoofing jamming digital intermediate frequency signal into an analog intermediate frequency signal and an analog radio frequency signal. The power amplifier and the filter perform power amplification, out-of-band spurious suppression, harmonic suppression, etc. on the analog radio frequency signal to improve the quality of the spoofing jamming. The spatial deployment of the transmitting antenna is determined according to the spoofing strategy to ensure that each spoofing jamming is incident on the target authorized user to be spoofed according to the preset strategy. This part is the same as or similar to the existing spoofing jamming transmitting method, so the specific implementation process will not be described in detail.

[0111] It can be understood that if the spoofing interference forming unit includes an electro-optical converter, the spoofing interference transmitting unit needs to include an opto-electronic converter. The opto-electronic converter is used to convert the received 1-channel high-speed serial signal into i-channel spoofing interference digital intermediate frequency signals, and then process and transmit them. If the spoofing interference forming unit does not perform electro-optical conversion, the spoofing interference transmitting unit does not need opto-electronic conversion either.

[0112] Through the above spoofing interference generating device, a satellite navigation signal purification scheme for forming multiple satellite beams pointing to satellites based on an array antenna can be obtained. This scheme uses digital beamforming technology to control the radiation pattern of the planar array antenna, adaptively form receiving beams respectively pointing to visible satellites in the hemispherical airspace, and parallelly complete the purification of satellite navigation signals in the hemispherical airspace.

[0113] Moreover, the spoofing interference generating device for authorized users follows the design concept of "high cohesion and low coupling", and mainly consists of a planar array antenna, a radio frequency channel, a beamforming unit, a spoofing interference forming unit, a spoofing interference transmitting unit, etc.; the processing flow is clear, the interface relationship between units is simple, and the functions of each unit are complete. The planar array antenna is composed of multiple microstrip patch antennas with small volume and low cost; for the radio frequency channel, beamforming unit, spoofing interference forming unit, spoofing interference transmitting unit, etc., general components such as L-band multi-channel radio frequency chips, multi-channel AD chips, FPGA chips, navigation baseband chips, DA chips, optical modules, power amplifiers, etc. can be selected respectively; in terms of volume, cost, power consumption, and deployment, it is significantly better than the existing methods.

[0114] At the same time, during the purification process of satellite navigation signals, the obtained optimal weight vector is the optimal weight vector in the sense of MVDR, and has strong amplitude-phase compensation ability. Therefore, the amplitude-phase requirements for the radio frequency channel are significantly reduced compared with the existing methods, which is conducive to engineering implementation. In addition, since the optimal weight vector is the optimal weight vector in the sense of MVDR, for satellite navigation applications, the interference is stronger than the noise and satellite signals. To minimize the output variance, the radiation pattern of the array antenna must form a depression in the direction of the interference with dominant power. Therefore, satellite navigation signal purification can be completed in an external interference and transceiver mutual interference environment.

[0115] Based on the same inventive concept, the embodiment of the present application also provides a spoofing interference generating method for authorized users. This method can be implemented based on the spoofing interference generating device for authorized users in any of the above embodiments, or can also be implemented by designing a similar spoofing interference generating device using the same design concept.

[0116] Refer to Figure 2 , Figure 2 which is a schematic flow chart of the spoofing interference generating method for authorized users provided by an embodiment of the present application.

[0117] AsFigure 2 As shown in Figure 2 , the method for generating spoofing interference for authorized users in this embodiment includes the following steps:

[0118] Step S101: Obtain q channels of analog RF signals collected by a planar array antenna. Among them, the planar array antenna includes q microstrip patch antennas arranged in a planar manner according to a set rule; the q microstrip patch antennas are all used to receive RF signals in the hemispherical airspace to obtain q channels of analog RF signals.

[0119] Step S102: Process the q channels of analog RF signals to obtain q channels of analog intermediate-frequency signals, and convert the q channels of analog intermediate-frequency signals into q channels of digital intermediate-frequency signals.

[0120] Step S103: Obtain the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite.

[0121] Step S104: Based on the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the j-th satellite, calculate the optimal weighting vector w of the q channels of digital intermediate-frequency signals under the MVDR criterion, where j = 1, 2,..., i, and i is the number of all visible satellites in the hemispherical airspace. j , j = 1, 2,..., i, where i is the number of all visible satellites in the hemispherical airspace.

[0122] Step S105: Based on the i optimal weighting vectors w j Perform weighted calculations on the q channels of digital intermediate-frequency signals respectively to obtain i channels of satellite navigation digital intermediate-frequency signals.

[0123] Step S106: Process the i channels of satellite navigation digital intermediate-frequency signals according to a set spoofing strategy to obtain i channels of spoofing interference digital intermediate-frequency signals.

[0124] Step S107: Convert the i channels of spoofing interference digital intermediate-frequency signals into i channels of spoofing interference analog RF signals, and transmit the specified spoofing interference analog RF signals to the target authorized user to be spoofed according to the spoofing strategy.

[0125] Further, in step S104, based on the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the j-th satellite, calculating the weighting vector that minimizes the output variance of the planar array antenna under the gain constraint in the direction of the j-th satellite signal includes:

[0126] Based on the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite, calculate the incident directions of the i satellite signals in the array antenna coordinate system;

[0127] Based on the incident directions and the position vectors of the microstrip patch antennas in the array antenna coordinate system, calculate the steering vectors of the i satellite signals in the array antenna coordinate system;

[0128] Based on \(i\) steering vectors, calculate the weighted vector that minimizes the output variance of the planar array antenna under the gain constraint of \(i\) satellites, that is, the optimal weighted vector \(w\). j 。

[0129] Further, based on \(i\) steering vectors, calculate the weighted vector that minimizes the output variance of the planar array antenna under the gain constraint in the direction of the \(j\)th satellite signal, including:

[0130] Solve it using the sampling correlation matrix inversion algorithm, the recursive least squares method, or the orthogonal triangular decomposition-recursive least squares method;

[0131] Or, after reducing the rank using the multistage nested Wiener filtering algorithm, perform iterative solution.

[0132] Further, in step S103, obtaining the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the satellite includes:

[0133] Measure the attitude of the planar array antenna through an attitude sensor fixedly connected to the array antenna with the sensitive axis coinciding with the coordinate axis of the array antenna coordinate system, or estimate the attitude of the planar array antenna through the planar array antenna itself;

[0134] Determine the approximate position of the phase center of the planar array antenna as the phase center position of the planar array antenna through historical data, and determine the approximate position of the satellite as the position of the satellite through historical data; or, suppress interference through null control, capture and track the satellite navigation public signal, demodulate the navigation message to obtain the position of the satellite, and perform PVT solution to obtain the phase center position of the planar array antenna.

[0135] Among them, for the specific implementation methods and principles of each step of the spoofing interference generation method for authorized users, reference can be made to the corresponding content in the foregoing device embodiments, and details are not described herein again.

[0136] It can be understood that the same or similar parts in the above embodiments can be referred to each other, and the content not detailed in some embodiments can be seen in the same or similar content of other embodiments.

[0137] Any process or method description in the flowchart or described in other ways herein can be understood as representing a module, segment, or part of code including one or more executable instructions for implementing a specific logical function or process, and the scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a manner that is not shown or discussed, including in a substantially simultaneous manner or in the reverse order according to the involved functions, which should be understood by those skilled in the technical field to which the embodiments of the present invention belong.

[0138] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits with logic gate circuits for implementing logical functions on data signals, application specific integrated circuits with appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0139] Those of ordinary skill in the art can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing relevant hardware through a program. The program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0140] In addition, in each embodiment of the present invention, the functional units can be integrated into a processing module, or each unit can exist physically alone, or two or more units can be integrated into one module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. The above-mentioned storage medium can be a read-only memory, a magnetic disk, an optical disc, etc.

[0141] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0142] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for generating deceptive interference for authorized users, characterized in that: include: Acquire q-channel analog radio frequency signals collected by the planar array antenna; The planar array antenna comprises q microstrip patch antennas arranged in a plane according to a set rule; The q microstrip patch antennas are used to receive radio frequency signals in the hemispherical airspace to obtain q analog radio frequency signals; Processing the q analog radio frequency signals to obtain q analog intermediate frequency signals, and converting the q analog intermediate frequency signals into q digital intermediate frequency signals; Obtain the attitude of the planar array antenna, the phase center position of the planar array antenna and the position of the satellite; Based on the attitude of the planar array antenna, the phase center position of the planar array antenna and the position of the j-th satellite, a weighted vector that minimizes the output variance of the planar array antenna under the upward gain constraint of the j-th satellite signal is calculated, that is, the optimal weighted vector w for the q-channel digital intermediate frequency signal under the minimum variance distortion-free response criterion. j , j = 1, 2, ..., i, i is the number of all visible satellites in the hemispheric airspace; Based on the i optimal weighted vectors w j Performing weighted calculation on q digital intermediate frequency signals respectively to obtain i satellite navigation digital intermediate frequency signals; Processing the i-channel satellite navigation digital intermediate frequency signal according to the set deception strategy to obtain i-channel deception interference digital intermediate frequency signal; The i-channel deception jamming digital intermediate frequency signals are converted into i-channel deception jamming analog radio frequency signals, and the designated deception jamming analog radio frequency signals are transmitted to the target authorized user to be deceived according to the deception strategy.

2. The method according to claim 1, characterized in that The step of calculating a weighted vector that minimizes the output variance of the planar array antenna under the upward gain constraint of the j-th satellite signal based on the attitude of the planar array antenna, the phase center position of the planar array antenna, and the position of the j-th satellite comprises: Based on the attitude of the planar array antenna, the phase center position of the planar array antenna and the position of the satellite, calculate the arrival direction of i satellite signals in the array antenna coordinate system; Based on the incoming wave direction and the position vector of each of the microstrip patch antennas in the array antenna coordinate system, the steering vectors of i satellite signals in the array antenna coordinate system are calculated; Based on the i steering vectors, a weighted vector that minimizes the output variance of the planar array antenna under the constraint of the upward gain of the jth satellite signal is calculated, that is, the optimal weighted vector w j .

3. The method according to claim 2, characterized in that The step of calculating, based on the i steering vectors, a weighted vector that minimizes the output variance of the planar array antenna while satisfying the upward gain constraint of the i satellite signals comprises: The solution is solved by using sampling correlation matrix inversion algorithm, recursive least squares method or orthogonal triangular decomposition-recursive least squares method; Alternatively, a multi-stage nested Wiener filtering algorithm is used to reduce the rank and then an iterative solution is performed.

4. The method according to claim 1, characterized in that The obtaining of the attitude of the planar array antenna, the phase center position of the planar array antenna and the position of the satellite comprises: The attitude of the planar array antenna is measured by an attitude sensor which is fixedly connected to the array antenna and whose sensitive axis coincides with the coordinate axis of the array antenna coordinate system, or the attitude of the planar array antenna is estimated autonomously by the planar array antenna; The rough position of the phase center of the planar array antenna is determined through historical data as the phase center position of the planar array antenna, and the rough position of the satellite is determined through historical data as the position of the satellite; or, interference is suppressed through null control, the public signal of satellite navigation is captured and tracked, the navigation message is demodulated to obtain the position of the satellite, and the phase center position of the planar array antenna is obtained by PVT solution.

5. A deceptive interference generating device for authorized users, characterized in that: include: Planar array antenna, radio frequency channel, beamforming unit, deception interference forming unit and deception interference transmitting unit; The planar array antenna includes q microstrip patch antennas arranged in a plane according to a set rule; the q microstrip patch antennas are all used to receive radio frequency signals in a hemispherical airspace and obtain q analog radio frequency signals; The radio frequency channel includes q channels, each channel corresponds to one of the microstrip patch antennas, and the radio frequency channel is used to process the q analog radio frequency signals output by the q microstrip patch antennas through the q channels to obtain q analog intermediate frequency signals; The beamforming unit includes an analog-to-digital converter, a posture position determination module, an antenna weight vector calculation module and a multi-beam pointing formation module; The analog-to-digital converter is used to convert the q-channel analog intermediate frequency signal into a q-channel digital intermediate frequency signal; the attitude position determination module is used to determine the attitude of the planar array antenna, the phase center position of the planar array antenna and the position of the satellite; the antenna weight vector calculation module is used to calculate the optimal weight vector w for the q-channel digital intermediate frequency signal under the minimum variance distortion-free response criterion according to the attitude of the planar array antenna, the phase center position of the planar array antenna and the position of the j-th satellite. j , j = 1, 2, ..., i, i is the number of all visible satellites in the hemispheric airspace; the multi-beam pointing formation module is used to form a multi-beam pointing pattern based on the i optimal weighted vectors w j Performing weighted calculation on q digital intermediate frequency signals respectively to obtain i satellite navigation digital intermediate frequency signals; The deception interference forming unit is used to process the i-channel satellite navigation digital intermediate frequency signal according to the set deception strategy to obtain i-channel deception interference digital intermediate frequency signal; The deception interference transmitting unit is used to convert the i-channel deception interference digital intermediate frequency signal into i-channel deception interference analog radio frequency signal, and transmit the designated deception interference analog radio frequency signal to the target authorized user to be deceived according to the deception strategy.

6. The device according to claim 5, characterized in that In the planar array antenna, q microstrip patch antennas are arranged in a regular polygon or a circle, and the spacing between adjacent microstrip patch antennas does not exceed half the wavelength of the satellite navigation signal carrier.

7. The device according to claim 5, characterized in that The deception interference forming unit includes an electro-optical converter, and the electro-optical converter is used to convert i-channel deception interference digital intermediate frequency signals into 1-channel high-speed serial signal; The deception interference forming unit is connected to the deception interference transmitting unit via an optical cable, and the optical cable is used to transmit the one-channel high-speed serial signal converted by the electro-optical converter to the deception interference transmitting unit.

8. The device according to claim 6, characterized in that The deception jamming transmission unit comprises a photoelectric converter, and the electro-optical converter is used to convert the received 1-channel high-speed serial signal into i-channel deception jamming digital intermediate frequency signals before processing and transmitting.

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