Satellite navigation spoofing method, system and device based on smart metasurface
By deploying a smart metasurface module between the navigation satellite and the target receiver, and using a signal processing model to control the signal forwarding beam, the high cost and easy detection of existing satellite navigation deception technologies are solved, achieving a low-cost and high-success-rate navigation deception effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NAT UNIV OF DEFENSE TECH
- Filing Date
- 2023-09-18
- Publication Date
- 2026-05-29
AI Technical Summary
Existing satellite navigation spoofing technologies suffer from high costs, poor concealment, and ease of detection. In particular, generative and relay-based spoofing methods have limited effectiveness in detecting signal authenticity.
By deploying a smart metasurface module between the navigation satellite and the target receiver, and using a signal processing model to control the signal forwarding beam, the target receiver can be deceived. The specific steps include acquiring position information and antenna gain, determining the channel, constructing a signal processing model, and forming a signal forwarding beam by controlling the array element phase delay and amplitude gain of the RIS module to ensure that the forwarding signal power or signal-to-noise ratio reaches a set threshold.
It achieves low-cost, covert, and realistic navigation deception, improving the success rate of deception and reducing deployment complexity and cost.
Smart Images
Figure CN117233802B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of Position Navigation and Time (PNT) deception technology, and in particular to a satellite navigation deception method, system and device based on a smart metasurface. Background Technology
[0002] Currently, there are two main methods for deceiving radio navigation systems (including satellite navigation systems, TACAN, Loland-C, E-Loland, etc.): generative deception and relay deception. Generative deception utilizes publicly available or wirelessly acquired signal protocols, calculates signal parameters based on the deception trajectory, and then broadcasts false navigation signals, enabling both stationary point deception and trajectory deception. Relay deception, through processes such as receiving, storing, processing, regenerating, and broadcasting, deceives navigation receivers. It mainly includes instant relaying, recording and playback, and channel-delayed relaying, and can achieve both point deception and trajectory deception.
[0003] However, due to limitations in signal authenticity, the practical effectiveness of both generative and relay-based spoofing is limited. Firstly, the parameters of the authorization code modulation signal are not publicly available and are extremely difficult to detect and crack. Users capable of receiving authorized signals can easily eliminate the effects of generative spoofing. Secondly, relay-based spoofing signals exhibit obvious spoofing characteristics, such as signal delay, signal-to-noise ratio, and signal direction of arrival, allowing user receivers to detect and eliminate the spoofing using appropriate algorithms. While it is possible to generate near real-time, high signal-to-noise ratio fake navigation signals through receiving, storing, processing, and regenerating, this can also be classified as generative spoofing and cannot generate authorized navigation signals. Summary of the Invention
[0004] Therefore, it is necessary to provide a satellite navigation deception method, system, and device based on a reconfigurable intelligent surface (RIS) that can achieve low-cost, covert, and realistic deception effects to address the aforementioned technical problems.
[0005] A satellite navigation deception method based on a smart metasurface, the method comprising:
[0006] One or more RIS modules, fixed on a mobile or fixed carrier, are deployed between the navigation satellite and the target receiver to acquire the position information and antenna gain of the navigation satellite, the target receiver, and the RIS modules; wherein, the RIS modules are intelligent metasurface modules.
[0007] Based on the location information and antenna gain, the channel between the navigation satellite, the target receiver, and the RIS module is determined. The actual navigation signal transmitted by the navigation satellite is forwarded to the target receiver through the channel, and a signal processing model is constructed based on the signal obtained by the target receiver.
[0008] The signal forwarding beam of the RIS module is controlled by a signal processing model. Based on the signal forwarding beam control, the forwarding signal power of the RIS module and the actual signal power of the navigation satellite are obtained. When the ratio of the forwarding signal power to the actual signal power is greater than the set power ratio threshold, the deception of the target receiver is completed.
[0009] In one embodiment, determining the channel between the navigation satellite, the target receiver, and the RIS module based on location information and antenna gain includes:
[0010] Based on the position information of the navigation satellite and the target receiver, and the antenna gain, the channel from the navigation satellite to the target receiver is calculated and denoted as follows:
[0011]
[0012] Where f(t) is the channel from the navigation satellite to the target receiver, p T (t), p R (t) represent the positions of the navigation satellite transmitting antenna and the target receiver receiving antenna, respectively. The gain of the navigation satellite transmitting antenna in the direction of the target receiver. Let λ be the gain of the target receiver's receiving antenna in the direction of the navigation satellite, ||·|| be the modulo operation, and λ be the gain of the receiving antenna in the direction of the navigation satellite. c It is the actual carrier wavelength of the navigation signal;
[0013] Based on the position information of the navigation satellite and the RIS module, and the antenna gain, the channel from the navigation satellite to the RIS module is calculated and represented as follows:
[0014]
[0015] Where G(t) is the channel matrix from the navigation satellite to each element of the RIS module, p k (t) represents the position of the k-th element in the RIS module, where k = 1, ..., K, and K is the number of elements in the RIS module. The gain of the navigation satellite transmitting antenna in the direction of the kth element. This represents the gain of the k-th array element in the direction of the navigation satellite.
[0016] Based on the location information of the RIS module and the target receiver, and the antenna gain, the channel from the RIS module to the target receiver is calculated and determined, denoted as:
[0017]
[0018] Where H(t) is the channel matrix from each element of the RIS module to the target receiver. Let be the gain of the k-th array element in the direction of the target receiver. Let be the gain of the receiving antenna of the target receiver in the direction of the kth array element.
[0019] In one embodiment, constructing a signal processing model based on the signal acquired by the target receiver includes:
[0020] When a single navigation satellite exists, a single RIS module forwards the actual navigation signal to the target receiver. Simultaneously, the target receiver also receives the navigation signal directly from the navigation satellite. A signal processing model is constructed based on the signal acquired by the target receiver, represented as follows:
[0021]
[0022] Where y(t) represents the signal received by the target receiver, s0(t), s r (t), n y (t) represent the navigation signal directly from the navigation satellite to the target receiver, the relayed signal forwarded to the target receiver via the RIS module, and the noise signal from the target receiver, respectively. Let x(t) represent the actual navigation signal transmitted by the navigation satellite, and f be the intermediate frequency signal of the navigation satellite. c Let n be the carrier frequency. s (t) represents the navigation satellite noise signal, j represents the imaginary unit, and e is the natural constant. Let c be the propagation delay of the signal from the navigation satellite to the target receiver, and c0 be the speed of the signal in free space. These represent the element phase delay of the RIS module, the channel matrix from the navigation satellite to each element of the RIS module, the channel matrix from each element of the RIS module to the target receiver, and the signal amplification factor of the RIS module, respectively. Represents the field of complex numbers. Let φ denote the conjugate transpose of w(t). k This represents the phase delay of the k-th element in the RIS module. For the amplitude gain of the array elements, This represents the amplitude gain of the k-th element in the RIS module. For the forwarding signal vector of the RIS module, s(t)=[s(t-τ1),s(t-τ2),…,s(t-τ)]. K )] T ,s(t-τ kLet be the forwarding signal vector of the k-th element in the RIS module, where the superscript T indicates transpose, and This indicates the propagation delay of the signal after it is forwarded by the RIS module to the target receiver. This indicates the propagation delay of the signal from the navigation satellite to the RIS module. This represents the propagation delay of the signal from the RIS module to the target receiver. Let n(t) be the array element noise signal vector, and n(t) ~ CN(0) K ,σ 2 I K CN(u,Σ) represents a multidimensional complex Gaussian distribution with mean u and covariance Σ, where u is the mean and Σ is the covariance. K I represents the K×1 zero vector. K Let σ represent a K×K identity matrix. 2 This represents noise power.
[0023] In one embodiment, the method further includes: when a single navigation satellite is present, using a single RIS module to forward the actual navigation signal to the target receiver; simultaneously, the target receiver also receives navigation signals directly from the navigation satellite; and constructing a signal processing model based on the signals acquired by the target receiver, further represented as...
[0024]
[0025] in, This indicates that the differences between individual array elements are ignored, and the channel from each array element of the RIS module to the target receiver is... This indicates that the differences between the array elements are ignored, and the channels from each array element of the RIS module to the navigation satellite are represented by p. R (t) represents the position of the target receiver's receiving antenna, p S (t) represents the position of the reference element in the RIS module, which is located at the geometric center of the RIS module. T (t) represents the position of the navigation satellite's transmitting antenna. This indicates the direction of signal reception for each element in the RIS module. This indicates the direction of signal transmission for each element in the RIS module. c(t) represents the direction of the transmitted signal from the navigation satellite, and c(t) is the relay vector. This refers to the signal forwarding and propagation delay.
[0026] In one embodiment, the method further includes: when multiple navigation satellites and a single RIS module are present, using the single RIS module to forward the actual navigation signal to the target receiver, while the target receiver also receives navigation signals directly from the navigation satellites. A signal processing model is then constructed based on the signals acquired by the target receiver, represented as follows:
[0027]
[0028] Among them, f l (t) represents the channel from navigation satellite l to the target receiver, where l = 1, ..., L, and L is the number of navigation satellites, c l (t) represents the signal relay vector of navigation satellite l, g l (t) represents the channel from navigation satellite l to the RIS module, x l The intermediate frequency signal, δ, represents the signal of navigation satellite l. l For the signal relay and propagation delay of navigation satellite l, f c Let τ be the carrier frequency, τ(t) be the propagation delay of the signal from navigation satellite l to the target receiver, w(t) be the element phase delay of the RIS module, P(t) be the signal amplification factor of the RIS module, and n(t) be the element noise signal vector. y (t) represents the noise signal of the target receiver.
[0029] In one embodiment, the method further includes: when multiple navigation satellites and multiple RIS modules deployed at different locations exist, using multiple RIS modules to forward the real navigation signal to the target receiver, while the target receiver also receives the navigation signal directly from the navigation satellites. A signal processing model is constructed based on the signal acquired by the target receiver, represented as follows:
[0030]
[0031] Among them, h i (t) represents the channel from RIS module i to the target receiver, i = 1, ..., I, where I is the number of RIS modules. K represents the element phase delay of RIS module i. i This indicates the number of array elements in RIS module i. This represents the signal amplification factor of the RIS module i. This represents the relay vector of the signal transmitted by navigation satellite l via RIS module i. The channel x represents the connection between navigation satellite l and RIS module i. l This represents the intermediate frequency signal of navigation satellite l. The signal propagation delay of the signal transmitted by navigation satellite l and relayed by RIS module i is n. i (t) represents the array element noise signal vector of RIS module i.
[0032] In one embodiment, the signal forwarding beam of the RIS module is controlled by a signal processing model, and the forwarding signal power of the RIS module and the actual signal power of the navigation satellite are obtained based on the signal forwarding beam control. When the ratio of the forwarding signal power to the actual signal power is greater than a set power ratio threshold, the deception of the target receiver is completed, including:
[0033] The signal processing model controls the element phase delay and amplitude gain of the RIS module to form a signal forwarding beam control for the RIS module. Based on the signal forwarding beam control, the forwarding signal power of the RIS module and the actual signal power of the navigation satellite are obtained. When the ratio of the forwarding signal power to the actual signal power is greater than a set power ratio threshold, the target receiver is deceived. The ratio of the forwarding signal power to the actual signal power is expressed as:
[0034]
[0035] Among them, h i This represents the channel from RIS module i to the target receiver, where i = 1, ..., I, and I is the number of RIS modules. This represents the channel from navigation satellite l to RIS module i, where l = 1, ..., L, and L is the number of navigation satellites. This indicates the element phase delay of the RIS module i. f represents the relay vector of the signal transmitted by navigation satellite l via RIS module i. l This represents the channel from navigation satellite l to the target receiver. The signal amplification coefficients of each element in the RIS module i are the same and are...
[0036] In one embodiment, after controlling the signal forwarding beam of the RIS module through a signal processing model, the method further includes:
[0037] The signal processing model controls the element phase delay and amplitude gain of the RIS module, forming a signal forwarding beam control for the RIS module. Based on the signal forwarding beam control, the signal-to-noise ratio (SNR) of the forwarded signal from the RIS module and the SNR of the actual navigation satellite signal are obtained. When the ratio of the forwarded signal SNR to the actual signal SNR exceeds a set SNR threshold, the target receiver is deceived. Here, the SNR of the navigation satellite m forwarded by the RIS module r is... and the actual signal-to-noise ratio η of navigation satellite m m They are respectively represented as
[0038]
[0039]
[0040] Among them, the signal power transmitted by navigation satellite m is P m The noise power of each element in the RIS module is The target receiver noise is h r For the channel from the RIS module r to the target receiver, For the channel from navigation satellite m to RIS module r, the signal amplification coefficients of each element in RIS module r are the same and are... This indicates the element phase delay of the RIS module r. K is the relay vector of the signal transmitted by navigation satellite m via RIS module r. i f is the number of array elements in RIS module i. m This represents the channel from navigation satellite m to the target receiver.
[0041] A satellite navigation deception system based on a smart metasurface, the system comprising:
[0042] The system comprises a RIS module, a carrier, a control module, a navigation satellite, and a target receiver; wherein the RIS module is deployed between the navigation satellite and the target receiver and fixed on the carrier, and the control module is connected to both the RIS module and the carrier, and the control module is used to control the RIS module in real time via software to perform navigation deception.
[0043] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps:
[0044] One or more RIS modules, fixed on a mobile or fixed carrier, are deployed between the navigation satellite and the target receiver to acquire the position information and antenna gain of the navigation satellite, the target receiver, and the RIS modules; wherein, the RIS modules are intelligent metasurface modules.
[0045] Based on the location information and antenna gain, the channel between the navigation satellite, the target receiver, and the RIS module is determined. The actual navigation signal transmitted by the navigation satellite is forwarded to the target receiver through the channel, and a signal processing model is constructed based on the signal obtained by the target receiver.
[0046] The signal forwarding beam of the RIS module is controlled by a signal processing model. Based on the signal forwarding beam control, the forwarding signal power of the RIS module and the actual signal power of the navigation satellite are obtained. When the ratio of the forwarding signal power to the actual signal power is greater than the set power ratio threshold, the deception of the target receiver is completed.
[0047] The aforementioned satellite navigation deception method, system, and device based on intelligent metasurfaces deploy one or more RIS modules fixed on mobile or fixed carriers between the navigation satellite and the target receiver. Based on the RIS modules' ability to reflect or transmit navigation frequency band signals, they receive and forward real navigation signals from one or more directions, altering the propagation path of the real navigation signals. This eliminates the need for storing and processing navigation signals, resulting in low deployment complexity and cost. Furthermore, by constructing a signal processing model based on the signals acquired by the target receiver and controlling the signal forwarding beam of the RIS modules using this model, the received forwarded signal power in a certain area is made greater than the real signal power, thus improving the success rate of navigation deception. Attached Figure Description
[0048] Figure 1 This is a flowchart illustrating a satellite navigation deception method based on a smart metasurface in one embodiment;
[0049] Figure 2 This is a schematic diagram of a satellite navigation deception system based on a smart metasurface in one embodiment;
[0050] Figure 3 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation
[0051] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0052] In one embodiment, such as Figure 1 As shown, a satellite navigation deception method based on a smart metasurface is provided, including the following steps:
[0053] Step S1: Deploy one or more RIS modules fixed on a mobile or fixed carrier between the navigation satellite and the target receiver, and acquire the position information and antenna gain of the navigation satellite, the target receiver and the RIS modules; wherein, the RIS module is a smart metasurface module.
[0054] The carrier is not limited to one type or category. A reconfigurable smart metasurface is an artificial electromagnetic surface structure with programmable electromagnetic properties, typically composed of a large number of carefully designed electromagnetic units (or array elements). By applying control signals to the adjustable elements on these electromagnetic units, the electromagnetic properties of these units can be dynamically controlled, thereby achieving active intelligent control of space electromagnetic waves in a programmable manner, forming an electromagnetic field with controllable parameters such as amplitude, phase, polarization, and frequency. Utilizing the electromagnetic absorption, transmission, and scattering capabilities of RIS (Reconfigurable Intelligent Surface), especially the signal power amplification effect of active RIS, new positioning, navigation, and timing deception methods can be realized.
[0055] Step S2: Determine the channels between the navigation satellite, the target receiver, and the RIS module based on the location information and antenna gain. Forward the actual navigation signal transmitted by the navigation satellite to the target receiver through the channels, and construct a signal processing model based on the signal acquired by the target receiver.
[0056] Step S3: Control the signal forwarding beam of the RIS module through the signal processing model, and obtain the forwarding signal power of the RIS module and the real signal power of the navigation satellite according to the signal forwarding beam control. When the ratio of the forwarding signal power to the real signal power is greater than the set power ratio threshold, the deception of the target receiver is completed.
[0057] In one embodiment, determining the channel between the navigation satellite, the target receiver, and the RIS module based on location information and antenna gain includes:
[0058] Based on the position information of the navigation satellite and the target receiver, and the antenna gain, the channel from the navigation satellite to the target receiver is calculated and denoted as follows:
[0059]
[0060] Where f(t) is the channel from the navigation satellite to the target receiver, p T (t), p R (t) represent the positions of the navigation satellite transmitting antenna and the target receiver receiving antenna, respectively. The gain of the navigation satellite transmitting antenna in the direction of the target receiver. Let λ be the gain of the target receiver's receiving antenna in the direction of the navigation satellite, ||·|| be the modulo operation, and λ be the gain of the receiving antenna in the direction of the navigation satellite. c It is the actual carrier wavelength of the navigation signal;
[0061] Based on the position information of the navigation satellite and the RIS module, and the antenna gain, the channel from the navigation satellite to the RIS module is calculated and represented as follows:
[0062]
[0063] Where G(t) is the channel matrix from the navigation satellite to each element of the RIS module, p k (t) represents the position of the k-th element in the RIS module, where k = 1, ..., K, and K is the number of elements in the RIS module. The gain of the navigation satellite transmitting antenna in the direction of the kth element. This represents the gain of the k-th array element in the direction of the navigation satellite.
[0064] Based on the location information of the RIS module and the target receiver, and the antenna gain, the channel from the RIS module to the target receiver is calculated and determined, denoted as:
[0065]
[0066] Where H(t) is the channel matrix from each element of the RIS module to the target receiver. Let be the gain of the k-th array element in the direction of the target receiver. Let be the gain of the receiving antenna of the target receiver in the direction of the kth array element.
[0067] Specifically, the positions of the navigation satellite transmitting antenna, the target receiver receiving antenna, and the k-th array element in the RIS module are obtained by establishing a three-dimensional Cartesian coordinate system with the position of the reference array element of the RIS module as the origin. Each position is represented by three-axis coordinates (x, y, z). T This indicates that the reference array element is located at the geometric center of the RIS module.
[0068] In one embodiment, constructing a signal processing model based on the signal acquired by the target receiver includes:
[0069] When a single navigation satellite exists, a single RIS module forwards the actual navigation signal to the target receiver. Simultaneously, the target receiver also receives the navigation signal directly from the navigation satellite. A signal processing model is constructed based on the signal acquired by the target receiver, represented as follows:
[0070]
[0071] Where y(t) represents the signal received by the target receiver, s0(t), s r (t), n y (t) represent the navigation signal directly from the navigation satellite to the target receiver, the relayed signal forwarded to the target receiver via the RIS module, and the noise signal from the target receiver, respectively. Let x(t) represent the actual navigation signal transmitted by the navigation satellite, and f be the intermediate frequency signal of the navigation satellite. c Let n be the carrier frequency. s(t) represents the navigation satellite noise signal, j represents the imaginary unit, and e is the natural constant. Let c be the propagation delay of the signal from the navigation satellite to the target receiver, and c0 be the speed of the signal in free space. These represent the element phase delay of the RIS module, the channel matrix from the navigation satellite to each element of the RIS module, the channel matrix from each element of the RIS module to the target receiver, and the signal amplification factor of the RIS module, respectively. Represents the field of complex numbers. Let φ denote the conjugate transpose of w(t). k This represents the phase delay of the k-th element in the RIS module. For the amplitude gain of the array elements, This represents the amplitude gain of the k-th element in the RIS module. For the forwarding signal vector of the RIS module, s(t)=[s(t-τ1),s(t-τ2),…,s(t-τ)]. K )] T ,s(t-τ k Let be the forwarding signal vector of the k-th element in the RIS module, where the superscript T indicates transpose, and This indicates the propagation delay of the signal after it is forwarded by the RIS module to the target receiver. This indicates the propagation delay of the signal from the navigation satellite to the RIS module. This represents the propagation delay of the signal from the RIS module to the target receiver. Let n(t) be the array element noise signal vector, and n(t) ~ CN(0) K ,σ 2 I K CN(u,Σ) represents a multidimensional complex Gaussian distribution with mean u and covariance Σ, where u is the mean and Σ is the covariance. K I represents the K×1 zero vector. K Let σ represent a K×K identity matrix. 2 This represents noise power.
[0072] Specifically, the above signal processing model assumes a free-space propagation model and assumes an equivalent receiving area of... Indicates the array elements in the RIS module Directional gain, θ and These represent the signal elevation angle and azimuth angle of arrival, respectively.
[0073] In one embodiment, the method further includes: the navigation satellite noise signal propagating over long distances to the RIS module can be ignored, in which case the signal vector s(t) can also be expressed as
[0074]
[0075] Where a(γ,η) and b(α,β) are the guidance vectors of the array elements in the RIS module in the direction of the navigation satellite and the direction of the target receiver, respectively, and are expressed as follows:
[0076]
[0077] Where γ=θ(p S ,p T () is the elevation angle of the navigation satellite signal relative to the reflecting surface. It is the azimuth angle of the navigation satellite signal relative to the reflecting surface, α = θ(p S ,p R ), These are the elevation and azimuth angles of the target receiver relative to the reflecting surface, respectively. and p is the signal steering vector. S p T p R p k Equivalent to p above S (t), p T (t), p R (t), p k (t), where p1 and p2 represent the positions of the first and second array elements in the RIS module.
[0078] Therefore, when a single navigation satellite exists, a single RIS module is used to forward the actual navigation signal to the target receiver. Simultaneously, the target receiver also receives the navigation signal directly from the navigation satellite. Based on the signal acquired by the target receiver, a signal processing model is constructed, which is also represented as...
[0079]
[0080] in, This indicates that the differences between the individual array elements are ignored, and the channels from each array element of the RIS module to the target receiver are... This indicates that the differences between the array elements are ignored, and the channels from each array element of the RIS module to the navigation satellite are represented by p. R (t) represents the position of the target receiver's receiving antenna, p S (t) = [0,0,0] T This refers to the position of the reference element in the RIS module. The reference element is located at the geometric center of the RIS module. T (t) represents the position of the navigation satellite's transmitting antenna. This indicates the direction of signal reception for each element in the RIS module. This indicates the direction of signal transmission for each element in the RIS module. c(t) represents the direction of the transmitted signal from the navigation satellite, and c(t) is the relay vector. This refers to the signal forwarding and propagation delay.
[0081] Specifically, at this point, it is assumed that the direction of receiving signals and the direction of transmitting signals are approximately equal for each element of the RIS module, denoted as follows: and It is also assumed that the receiving and transmitting gains of the navigation satellite transmitting antenna, each element of the RIS module, and the target receiver receiving antenna are the same in the same direction and do not change with time.
[0082] In one embodiment, it is also included: it is understood that, based on the signal processing model when there is a single navigation satellite, when there are multiple navigation satellites, the signal actually processed by the target receiver is the sum of the signals of multiple satellites and their relay signals, plus the target receiver noise.
[0083] Specifically, when multiple navigation satellites and a single RIS module exist, the single RIS module forwards the actual navigation signal to the target receiver. Simultaneously, the target receiver also receives navigation signals directly from the navigation satellites. A signal processing model is constructed based on the signals acquired by the target receiver, represented as follows:
[0084]
[0085] Among them, f l (t) represents the channel from navigation satellite l to the target receiver, where l = 1, ..., L, and L is the number of navigation satellites, c l (t) represents the signal relay vector of navigation satellite l, g l (t) represents the channel from navigation satellite l to the RIS module, x l The intermediate frequency signal of navigation satellite l, δ l For the signal relay and propagation delay of navigation satellite l, f c Let τ be the carrier frequency, τ(t) be the propagation delay of the signal from navigation satellite l to the target receiver, w(t) be the element phase delay of the RIS module, P(t) be the signal amplification factor of the RIS module, and n(t) be the element noise signal vector. y (t) represents the noise signal of the target receiver.
[0086] It is understandable that when there are multiple navigation satellites, using a single RIS module can divide the array elements within the RIS module and assign them to different navigation satellites, which is equivalent to using multiple RIS modules.
[0087] In one embodiment, it further includes:
[0088] When multiple navigation satellites and multiple RIS modules deployed in different locations exist, multiple RIS modules are used to forward the real navigation signal to the target receiver. Simultaneously, the target receiver also receives navigation signals directly from the navigation satellites. A signal processing model is constructed based on the signals acquired by the target receiver, represented as follows:
[0089]
[0090] Among them, h i (t) represents the channel from RIS module i to the target receiver, i = 1, ..., I, where I is the number of RIS modules. K represents the element phase delay of RIS module i. i This indicates the number of array elements in RIS module i. This represents the signal amplification factor of the RIS module i. This represents the relay vector of the signal transmitted by navigation satellite l via RIS module i. The channel representing the connection from navigation satellite l to RIS module i, x l This represents the intermediate frequency signal of navigation satellite l. The signal propagation delay of the signal transmitted by navigation satellite l and relayed by RIS module i is n. i (t) represents the array element noise signal vector of RIS module i.
[0091] It is understandable that in the above signal processing model, the channel and time delay are determined by the antenna gain and position of the navigation satellite, the RIS module, and the target receiver. The position of the RIS module, the element phase delay and the element amplitude gain of the RIS module are controllable parts. By controlling the element phase delay and the element amplitude gain of the RIS module, the signal forwarding beam is controlled, so that the signal power and signal-to-noise ratio in the forwarded signal are at an appropriate level, thereby increasing the probability of the receiver capturing the forwarded signal.
[0092] In one embodiment, the method further includes: controlling the element phase delay and element amplitude gain of the RIS module through a signal processing model to form a signal forwarding beam control for the RIS module; and obtaining the forwarding signal power of the RIS module and the actual signal power of the navigation satellite based on the signal forwarding beam control; when the ratio of the forwarding signal power to the actual signal power is greater than a set power ratio threshold, the deception of the target receiver is completed; wherein, the ratio of the forwarding signal power to the actual signal power is expressed as...
[0093]
[0094] Among them, h i This represents the channel from RIS module i to the target receiver, where i = 1, ..., I, and I is the number of RIS modules. This represents the channel from navigation satellite l to RIS module i, where l = 1, ..., L, and L is the number of navigation satellites. This indicates the element phase delay of the RIS module i. f represents the relay vector of the signal transmitted by navigation satellite l via RIS module i. l This represents the channel from navigation satellite l to the target receiver. The signal amplification coefficients of each element in the RIS module i are the same and are...
[0095] Specifically, the power ratio threshold can be set to 1.
[0096] In one embodiment, after controlling the signal forwarding beam of the RIS module through a signal processing model, the method further includes:
[0097] The signal processing model controls the element phase delay and amplitude gain of the RIS module, forming a signal forwarding beam control for the RIS module. Based on the signal forwarding beam control, the signal-to-noise ratio (SNR) of the forwarded signal from the RIS module and the SNR of the actual navigation satellite signal are obtained. When the ratio of the forwarded signal SNR to the actual signal SNR exceeds a set threshold, the target receiver is deceived. For the same satellite signal, different RIS modules have different forwarding delays, which are considered as multipath interference. In this case, the SNR of the navigation satellite m forwarded by RIS module r is... Represented as
[0098]
[0099] And since the power of the real signal reaching the receiver is much smaller than the noise power, ignoring the interference between real signals, based on the assumption of no correlation between different satellite signals and noise signals, the signal-to-noise ratio η of the real signal of navigation satellite m is... m Represented as
[0100]
[0101] Among them, the signal power transmitted by navigation satellite m is P m The noise power of each element in the RIS module is The target receiver noise is h r For the channel from the RIS module r to the target receiver, For the channel from navigation satellite m to RIS module r, the signal amplification coefficients of each element in RIS module r are the same and are... This indicates the element phase delay of the RIS module r. K is the relay vector of the signal transmitted by navigation satellite m via RIS module r. if is the number of array elements in RIS module i. m This represents the channel from navigation satellite m to the target receiver.
[0102] Furthermore, based on the above calculation principle, in order to achieve the purpose of deception, by controlling the phase delay and amplitude gain of each element of the RIS module, the signal-to-noise ratio (SNR) of the relayed signal can be made greater than that of the real signal. There are several ways to achieve this goal. One approach is to use I RIS modules to relay L navigation satellite signals, where I = L, and by controlling the phase delay of each element in RIS module i, the beam gain of the relayed navigation satellite l signal can be increased. Reaching the maximum value Furthermore, it ensures that the beam gain of the RIS module for other satellite signals is at a relatively low value. The formula for calculation is:
[0103] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.
[0104] In one embodiment, such as Figure 2 As shown, a satellite navigation deception system based on a smart metasurface is provided, including: a RIS module 1, a carrier 2, a control module 3, a navigation satellite 4, and a target receiver 5; wherein, the RIS module 1 is deployed between the navigation satellite 4 and the target receiver 5 and fixed on the carrier 2, and the control module 3 is connected to the RIS module 1 and the carrier 2 respectively, and the control module 3 is used to control the RIS module 1 to perform navigation deception in real time through software.
[0105] Specific limitations regarding the satellite navigation deception system based on intelligent metasurfaces can be found in the limitations of the satellite navigation deception method based on intelligent metasurfaces mentioned above, and will not be repeated here. Each module in the aforementioned satellite navigation deception system based on intelligent metasurfaces can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.
[0106] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 3 As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When executed by the processor, the computer program implements a satellite navigation deception method based on a smart metasurface. The display screen can be a liquid crystal display (LCD) or an e-ink display. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device's casing, or an external keyboard, touchpad, or mouse.
[0107] Those skilled in the art will understand that Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.
[0108] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to perform the following steps:
[0109] Deploy one or more RIS modules fixed on a mobile or fixed carrier between the navigation satellite and the target receiver, and acquire the position information and antenna gain of the navigation satellite, the target receiver and the RIS modules;
[0110] Based on the location information and antenna gain, the channel between the navigation satellite, the target receiver, and the RIS module is determined. The actual navigation signal transmitted by the navigation satellite is forwarded to the target receiver through the channel, and a signal processing model is constructed based on the signal obtained by the target receiver.
[0111] The signal forwarding beam of the RIS module is controlled by a signal processing model. Based on the signal forwarding beam control, the forwarding signal power of the RIS module and the actual signal power of the navigation satellite are obtained. When the ratio of the forwarding signal power to the actual signal power is greater than the set power ratio threshold, the deception of the target receiver is completed.
[0112] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0113] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A satellite navigation deception method based on intelligent metasurfaces, characterized in that, The method includes: One or more RIS modules fixed on a mobile or fixed carrier are deployed between the navigation satellite and the target receiver to acquire the position information and antenna gain of the navigation satellite, the target receiver, and the RIS modules; wherein, the RIS modules are intelligent metasurface modules. Based on the location information and antenna gain, the channel between the navigation satellite, the target receiver, and the RIS module is determined. The actual navigation signal transmitted by the navigation satellite is forwarded to the target receiver through the channel, and a signal processing model is constructed based on the signal obtained by the target receiver. The signal forwarding beam of the RIS module is controlled by the signal processing model, and the forwarding signal power of the RIS module and the real signal power of the navigation satellite are obtained according to the signal forwarding beam control. When the ratio of the forwarding signal power to the real signal power is greater than the set power ratio threshold, the deception of the target receiver is completed. The process of constructing a signal processing model based on the signal acquired by the target receiver includes: When a single navigation satellite is present, a single RIS module forwards the actual navigation signal to the target receiver. Simultaneously, the target receiver also receives the navigation signal directly from the navigation satellite. A signal processing model is constructed based on the signal acquired by the target receiver, represented as follows: ； in, This indicates that the target receiver is receiving the signal. , , These represent the navigation signal directly from the navigation satellite to the target receiver, the relayed signal forwarded to the target receiver via the RIS module, and the noise signal from the target receiver, respectively. This represents the actual navigation signals transmitted by navigation satellites. The intermediate frequency signal for navigation satellites, For carrier frequency, For navigation satellite noise signals, j Represents the imaginary unit. It is a natural constant. The propagation delay of the signal from the navigation satellite to the target receiver. The speed at which a signal propagates in free space. These represent the element phase delay of the RIS module, the channel matrix from the navigation satellite to each element of the RIS module, the channel matrix from each element of the RIS module to the target receiver, and the signal amplification factor of the RIS module, respectively. Represents the field of complex numbers. express The conjugate transpose of . Indicates the first in the RIS module k The phase delay of each array element For the amplitude gain of the array elements, The first in the RIS module k The amplitude gain of each array element Forward signal vectors for the RIS module, , The first in the RIS module k The forwarding signal vector of each array element, superscript T Indicates transpose, and This indicates the propagation delay of the signal after it is forwarded by the RIS module to the target receiver. This indicates the propagation delay of the signal from the navigation satellite to the RIS module. This represents the propagation delay of the signal from the RIS module to the target receiver. The noise signal vector of the array elements. This indicates that the array element noise signal vector follows a multidimensional complex Gaussian distribution. The mean is The covariance is The multidimensional complex Gaussian distribution, express Zero vector, express identity matrix For noise power, , These indicate the positions of the navigation satellite transmitting antenna and the target receiver receiving antenna, respectively. Indicates the first in the RIS module k The position of each array element, and , This represents the number of array elements in the RIS module.
2. The method according to claim 1, characterized in that, Determining the channels between the navigation satellite, the target receiver, and the RIS module based on the location information and antenna gain includes: Based on the position information of the navigation satellite and the target receiver, and the antenna gain, the channel from the navigation satellite to the target receiver is calculated and denoted as follows: ； in, It is the channel through which signals travel from navigation satellites to the target receiver. The gain of the navigation satellite transmitting antenna in the direction of the target receiver. The gain of the target receiver's receiving antenna in the direction of the navigation satellite. For modulo operation, It is the actual carrier wavelength of the navigation signal; Based on the position information of the navigation satellite and the RIS module, and the antenna gain, the channel from the navigation satellite to the RIS module is calculated and represented as follows: ； in, It is the channel matrix of the signal from the navigation satellite to each element of the RIS module. For navigation satellite transmitting antennas in the k Gain in each element direction For the first k Gain of each element in the direction of navigation satellite; Based on the location information of the RIS module and the target receiver, and the antenna gain, the channel from the RIS module to the target receiver is calculated and determined, denoted as: ； in, It is the channel matrix from each element of the RIS module to the target receiver. For the first k The gain of each array element in the direction of the target receiver. For the target receiver receiving antenna at the 1st k Gain in each element direction.
3. The method according to claim 1, characterized in that, The method further includes: When a single navigation satellite is present, a single RIS module forwards the actual navigation signal to the target receiver. Simultaneously, the target receiver also receives the navigation signal directly from the navigation satellite. Based on the signal acquired by the target receiver, a signal processing model is constructed and represented as follows: ； in, This indicates that the differences between the individual array elements are ignored, and the channels from each array element of the RIS module to the target receiver are... This indicates that the differences between individual array elements are ignored, and the channels from each array element of the RIS module to the navigation satellite are... This refers to the position of the receiving antenna of the target receiver. This represents the position of the reference element in the RIS module, located at the geometric center of the RIS module. The location of the navigation satellite transmitting antenna. This indicates the direction of signal reception for each element in the RIS module. This indicates the direction of signal transmission for each element in the RIS module. Indicates the direction of the navigation satellite's transmitted signal. Forwarding vector, This refers to the signal forwarding and propagation delay.
4. The method according to claim 3, characterized in that, The method further includes: When multiple navigation satellites and a single RIS module are present, the single RIS module forwards the actual navigation signal to the target receiver. Simultaneously, the target receiver also receives navigation signals directly from the navigation satellites. A signal processing model is constructed based on the signals acquired by the target receiver, represented as follows: ； in, Indicates navigation satellite The channel to the target receiver. , L For the number of navigation satellites, Indicates navigation satellite The signal forwarding vector, Indicates navigation satellite Channel to the RIS module, Indicates navigation satellite intermediate frequency signal, For navigation satellites Signal forwarding and propagation delay For carrier frequency, For signals from navigation satellites The propagation delay directly to the target receiver. For the element phase delay of the RIS module, This represents the signal amplification factor of the RIS module. The noise signal vector of the array elements. The target receiver noise signal.
5. The method according to claim 4, characterized in that, The method further includes: When multiple navigation satellites and multiple RIS modules deployed in different locations exist, multiple RIS modules are used to forward the real navigation signal to the target receiver. Simultaneously, the target receiver also receives navigation signals directly from the navigation satellites. A signal processing model is constructed based on the signals acquired by the target receiver, represented as follows: ； in, Indicates RIS module The channel to the target receiver. , I The number of RIS modules, Indicates RIS module The phase delay of the array elements Indicates RIS module The number of array elements, Indicates RIS module The signal amplification factor, Indicates navigation satellite The transmitted signal passes through the RIS module Forwarding vector, Indicates navigation satellite To RIS module The channel, Indicates navigation satellite intermediate frequency signal, For navigation satellites The transmitted signal passes through the RIS module Forwarding signal propagation delay Indicates RIS module The array element noise signal vector.
6. The method according to claim 5, characterized in that, The signal forwarding beam of the RIS module is controlled by the signal processing model, and the forwarding signal power of the RIS module and the actual signal power of the navigation satellite are obtained based on the signal forwarding beam control. When the ratio of the forwarding signal power to the actual signal power is greater than a set power ratio threshold, the deception of the target receiver is completed, including: The signal processing model controls the element phase delay and amplitude gain of the RIS module to form a signal forwarding beam control for the RIS module. Based on the signal forwarding beam control, the forwarding signal power of the RIS module and the actual signal power of the navigation satellite are obtained. When the ratio of the forwarding signal power to the actual signal power is greater than a set power ratio threshold, the target receiver is deceived. The ratio of the forwarding signal power to the actual signal power is expressed as... ； in, Indicates RIS module The channel to the target receiver. , The number of RIS modules, Indicates navigation satellite To RIS module The channel, , For the number of navigation satellites, Indicates RIS module The phase delay of the array elements Indicates navigation satellite The transmitted signal passes through the RIS module Forwarding vector, Indicates navigation satellite Channel to the target receiver, RIS module The amplification factor of each array element is the same and is .
7. The method according to claim 6, characterized in that, After controlling the signal forwarding beam of the RIS module through the aforementioned signal processing model, the method further includes: The signal processing model controls the element phase delay and element amplitude gain of the RIS module, forming a signal forwarding beam control for the RIS module. Based on the signal forwarding beam control, the signal-to-noise ratio (SNR) of the RIS module's forwarding signal and the SNR of the navigation satellite's actual signal are obtained. When the ratio of the forwarding signal SNR to the actual signal SNR is greater than a set SNR ratio threshold, the deception of the target receiver is achieved. The RIS module... Retransmitted navigation satellites signal-to-noise ratio and navigation satellites True signal-to-noise ratio They are respectively represented as ； ； Among them, navigation satellites The transmitted signal power is The noise power of each element in the RIS module is The target receiver noise is , For RIS module The channel to the target receiver. For navigation satellites To RIS module The channel, RIS module The amplification factor of each array element is the same and is , Indicates RIS module The phase delay of the array elements For navigation satellites The transmitted signal passes through the RIS module Forwarding vector, For RIS module The number of array elements, Indicates navigation satellite The channel to the target receiver.
8. A satellite navigation deception system based on a smart metasurface, characterized in that, The system is used to execute the satellite navigation deception method based on smart metasurfaces as described in any one of claims 1-7, the system comprising: The system comprises a RIS module, a carrier, a control module, a navigation satellite, and a target receiver; wherein the RIS module is deployed between the navigation satellite and the target receiver and fixed on the carrier, and the control module is connected to both the RIS module and the carrier, and the control module is used to control the RIS module in real time via software to perform navigation deception.
9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.