Satellite navigation anti-deception method based on dynamic trend characteristics

Abstract

The invention provides a satellite navigation anti-cheating method based on dynamic trend characteristics, which comprises the following steps: respectively constructing two short-time sliding window arrays based on an inertial navigation pure inertial positioning signal sequence and a satellite navigation positioning signal sequence, dynamically updating data in a sliding window along with arrival of a positioning signal at a new moment, respectively establishing two north-east-earth coordinate systems by taking a pure inertial positioning signal and a satellite navigation positioning signal at the moment as coordinate origins according to the total duration of data in the window; respectively calculating three-dimensional space vectors between moment positioning signals in the short-time window array of the inertial navigation pure inertial positioning signal and the satellite navigation positioning signal and moment positioning signals in a space coordinate system origin, namely a short-time window; based on the three-dimensional space vector, calculating cosine similarity to represent trend consistency between the two positioning signal sequences; threshold judgment and dynamic adjustment are carried out, so that alarm output is carried out; according to the application, the survivability of the satellite navigation carrier in a complex electromagnetic environment and the reliability of task execution are effectively improved.

Description

Technical Field

[0001] This application belongs to the field of satellite navigation technology, and in particular relates to a satellite navigation anti-spoofing method based on dynamic trend characteristics. Background Technology

[0002] As an important navigation technology, satellite navigation systems (GNSS) can provide precise position, velocity, and time (PVT) information for vehicles such as cars, ships, and aircraft, supporting them in navigation control, path planning, and mission execution.

[0003] The most widely used satellite navigation is susceptible to interference and spoofing. Current spoofing detection methods (such as abnormal satellite detection and signal-to-noise ratio change detection) are ineffective against repeater-type spoofing sources that relay real signals. Although pure inertial navigation systems (INS) have anti-interference characteristics, they have error accumulation characteristics, and navigation accuracy degrades over time and cannot provide time information. Inertial navigation and satellite navigation combined navigation systems also face the risk of spoofing signal contamination. Regardless of whether the algorithm is loosely coupled or tightly coupled, abnormal satellite navigation signals may directly lead to state estimation errors. Summary of the Invention

[0004] The purpose of this invention is to provide a satellite navigation anti-spoofing method based on dynamic trend characteristics, which can effectively improve the survivability and mission reliability of satellite navigation carriers in complex electromagnetic environments, and provide key technical support for accurate navigation in high-threat scenarios.

[0005] This application provides a satellite navigation anti-spoofing method based on dynamic trend features, the method comprising: Step 1: Collect samples separately Inertial navigation pure inertial positioning signal at all times and satellite positioning signals ; Step 2, using All inertial navigation pure inertial positioning signals within the time period and satellite positioning signals Two sliding window arrays can be constructed separately:

[0006]

[0007] Step 3, with Pure inertial positioning signal measured by inertial navigation at time 10:00 and satellite positioning signals Establish two North-East-Ground coordinate systems with the origin as the coordinate origin; Step 4: Calculate the short-time window arrays of the inertial navigation pure inertial positioning signal and the satellite navigation positioning signal respectively. The time-based positioning signal and the origin of the spatial coordinate system within the short-time window Step 5: Calculate the cosine similarity based on the three-dimensional spatial vectors between the location signals at each moment. Step 6: Determine and dynamically adjust the threshold, and output an alarm based on the threshold.

[0008] Preferably, step 1 further includes: Timestamp synchronization ensures that the inertial navigation pure inertial positioning signal is aligned with the satellite navigation positioning signal.

[0009] Preferably, step 2 includes: The input signal frequency is set to 10Hz, meaning a position signal will be acquired every 100ms. The total duration of the constructed sliding window is... ; Utilizing short window All inertial navigation pure inertial positioning signals within a time period and satellite positioning signals Two sliding window arrays can be constructed separately:

[0010]

[0011] This array is dynamically updated as new time-of-flight data is input, short window The duration needs to be adjusted according to the motion characteristics of the carrier.

[0012] Preferably, step 4 includes: Based on the WGS-84 model, the three-dimensional spatial vector between the last point in the short-time window array of the inertial navigation pure inertial positioning signal and the satellite navigation positioning signal and the origin of the spatial coordinate system, i.e., the first point in the short-time window, is calculated respectively.

[0013] Preferably, the step of calculating the three-dimensional spatial vector between the last point in the short-time window array of the inertial navigation pure inertial positioning signal and the satellite navigation positioning signal, respectively, and the origin of the spatial coordinate system, i.e., the first point in the short-time window, based on the WGS-84 model, includes: Taking the Earth's radius as a fixed value of 6,371,288, the distance from the origin of the spatial coordinate system of the satellite navigation positioning location to the Earth's center is: ; Northward coordinate difference between two points That is: ; Eastward coordinate difference correction amount for: ; Eastward coordinate difference between two points for: ; Difference between ground coordinates of two points for: ; The final three-dimensional spatial vector of the satellite positioning signal is ; Similarly, the three-dimensional spatial vector of the inertial navigation positioning signal is: .

[0014] Preferably, step 5 includes: If satellite navigation signals are spoofed, their positioning results will deviate. The actual trajectory trend of a moving vehicle will inevitably differ from the satellite navigation positioning trajectory trend. However, within a short timeframe, the inertial navigation (INS) pure positioning signal can accurately represent the vehicle's true motion trend. Therefore, when satellite navigation is spoofed, the INS pure positioning trajectory vector and the satellite navigation positioning trajectory vector will inevitably have a certain angle, meaning their trajectory vector trends will be inconsistent. (Cosine similarity) The directional similarity between two vectors can be quantitatively measured, and the calculation formula is as follows:

[0015] The range of cosine similarity is [-1, 1], where 1 indicates that the directions are completely consistent, 0 indicates that the directions are orthogonal and have no correlation, and -1 indicates that the directions are completely opposite.

[0016] Preferably, the threshold determination and dynamic adjustment includes: The velocity information output by the pure inertial navigation positioning signal has high reliability and is not affected by external interference or deceptive signals. Therefore, the total velocity of the carrier can be calculated using the velocity signal output by the pure inertial navigation positioning signal. The maneuverability of the satellite-guided vehicle is determined by its total speed; To avoid the inability to calculate cosine similarity when the carrier is stationary, the carrier's speed must be greater than or equal to... Therefore, based on the total flight speed and division-to-zero protection, different trend detection thresholds are adopted as follows: .

[0017] Preferably, the alarm output based on the threshold includes: Alarm signal: When If an alarm signal is sent, the flight control system can switch to pure INS navigation mode to prevent the carrier from being tricked, which could lead to mission failure or loss of control of the carrier.

[0018] The beneficial effects of this invention are: This application proposes an anti-spoofing algorithm based on the trajectory trend characteristics of inertial navigation and satellite navigation. By combining dynamic threshold adjustment and multi-level defense response mechanism, it achieves satellite navigation spoofing detection with high sensitivity and low false alarm rate. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A flowchart illustrating a satellite navigation anti-spoofing method based on dynamic trend features provided in this application embodiment; Figure 2 A schematic diagram of the navigation trajectory (deception trajectory) and flight trajectory provided for embodiments of this application; Figure 3 Trend detection result graph (threshold 0.96) provided for embodiments of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0023] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0025] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] Please see Figures 1-3 This invention proposes a lightweight, highly sensitive system-level anti-spoofing algorithm. This scheme leverages the consistency between the trends of the inertial navigation pure inertial trajectory and the satellite navigation trajectory within a short sliding window. The method combines trajectory vector calculation in a local spatial coordinate system with a dynamic threshold adjustment strategy, overcoming the limitations of traditional detection methods.

[0027] This invention aims to provide a satellite navigation anti-spoofing algorithm based on dynamic trend characteristics, which can effectively improve the survivability and mission reliability of satellite navigation vehicles in complex electromagnetic environments, and provide key technical support for accurate navigation in high-threat scenarios.

[0028] This invention utilizes the trend characteristics of inertial navigation system (INS) signals and satellite navigation signals, combined with a dynamic threshold mechanism, to achieve highly sensitive detection and protection against satellite navigation spoofing attacks. See the supplementary description for a flowchart of the technical solution. Figure 1 The core steps are as follows: Step 1: Data Synchronization Input The input data consists of inertial navigation pure inertial positioning signals and satellite navigation positioning signals. For example, time:

[0029]

[0030] in, Indicates location, Indicates the pure inertial positioning signal of inertial navigation. Indicates satellite positioning signal; Indicates longitude, in degrees (°); Indicates latitude, with the unit being degrees (°); Indicates height, in meters (m); express Inertial navigation pure inertial positioning position at any moment express Inertial navigation pure inertial positioning longitude at any moment express Inertial navigation pure inertial positioning latitude at any moment express The inertial navigation pure inertial positioning altitude at any given moment; express real-time satellite positioning location express The satellite navigation positioning longitude at any time express The latitude and longitude of satellite navigation positioning at any time express The satellite navigation positioning altitude at any given time. This algorithm requires timestamp synchronization to ensure that the inertial navigation pure inertial positioning signal is aligned with the satellite navigation positioning signal.

[0031] Step 2: Short-time window construction The input signal frequency is set to 10Hz, meaning a position signal will be acquired every 100ms. The total duration of the constructed sliding window is... Utilizing all inertial navigation pure inertial positioning signals within a short time window. and satellite positioning signals Two sliding window arrays can be constructed separately:

[0032]

[0033] in, This represents the sliding window array of pure inertial navigation signals. This represents the sliding window array for satellite navigation signals.

[0034] This array is dynamically updated as new time-of-flight data is input, short window The duration needs to be adjusted according to the motion characteristics of the carrier. See the attached instructions for the simulation trajectory diagram of a ground-speed UAV as the carrier. Figure 2 ...

[0035] Step 3: Define the local spatial coordinate system by Pure inertial positioning signal measured by inertial navigation at time 10:00 and satellite positioning signals Establish two North-East-Ground coordinate systems with the origin as the coordinate origin.

[0036] Step 4: Calculation of 3D Local Space Vectors Based on the WGS-84 model, the three-dimensional vector between the last point in the short-time window array of the inertial navigation pure inertial positioning signal and the origin of the spatial coordinate system (i.e., the first point in the short-time window) is calculated. Taking the satellite navigation positioning signal as an example, the method is as follows: Taking the Earth's radius as a fixed value of 6,371,288, the distance from the origin of the spatial coordinate system of the satellite navigation positioning location to the Earth's center is:

[0037] Northward coordinate difference between two points That is: .

[0038] Eastward coordinate difference correction amount for: .

[0039] Eastward coordinate difference between two points for: .

[0040] Difference between ground coordinates of two points for: .

[0041] The final three-dimensional spatial vector of the satellite positioning signal is Similarly, the three-dimensional spatial vector of the inertial navigation positioning signal is: .

[0042] in, This indicates the distance from the satellite's location to the Earth's center. , ,and These represent the differences in north, east, and ground coordinates within the window, respectively. Indicates the correction amount for the eastward coordinate difference. and These represent the in-window vectors of the inertial navigation pure inertial signal and the satellite navigation signal, respectively. The two vectors can represent the short-term trends of the two signals, respectively.

[0043] Step 6: Cosine similarity calculation If satellite navigation signals are spoofed, their positioning results will deviate. The actual trajectory trend of a moving vehicle will inevitably differ from the satellite navigation positioning trajectory trend. However, in the short term, the inertial navigation pure positioning signal can accurately represent the vehicle's true motion trend. Therefore, when satellite navigation is spoofed, the inertial navigation pure positioning trajectory vector and the satellite navigation positioning trajectory vector will inevitably have a certain angle, meaning their trajectory vector trends will be inconsistent. Cosine similarity ( The directional similarity between two vectors can be quantitatively measured, and its calculation formula is as follows:

[0044] Note: The range of cosine similarity is [-1, 1], where 1 indicates that the directions are completely consistent, 0 indicates that the directions are orthogonal (no correlation), and -1 indicates that the directions are completely opposite. See the appendix for simulation results of trend detection. Figure 3 .

[0045] Step 7: Threshold Determination and Dynamic Adjustment The necessity of dynamic threshold adjustment When the carrier is stationary, the coordinate difference within the sliding window is zero, making cosine similarity calculation impossible; therefore, a minimum speed limit for the carrier is required. When the carrier is in low-speed motion, the inertial navigation pure inertial positioning trajectory and the satellite navigation positioning trajectory are highly consistent in direction. Even if the satellite navigation is deceived, the low speed of the carrier results in a small angle between the direction vectors generated by the motion; therefore, the threshold for trend detection needs to be increased (e.g., ...). To avoid false alarms; however, during high-speed motion, the direction of the vehicle's trajectory may change abruptly, requiring a reduction in the threshold (e.g., ...). This is to improve the sensitivity of anti-spoofing algorithms and avoid missing spoofing reports.

[0046] Maneuver status determination scheme The velocity information output by the pure inertial navigation positioning signal has high reliability and is not affected by external interference or deceptive signals. Therefore, the total velocity of the carrier can be calculated from the velocity signal output by the pure inertial navigation positioning signal. The maneuverability of the satellite-guided vehicle is determined by its total velocity; to avoid the inability to calculate cosine similarity when the vehicle is stationary, the vehicle's velocity must be greater than or equal to... Therefore, different trend detection thresholds are set based on total flight speed and division-to-zero protection:

[0047] in, Indicates the total speed of the carrier, This indicates the selected threshold.

[0048] Step 8: Alarm Output Alarm signal: When If an alarm signal is sent, the flight control system can switch to pure INS navigation mode to prevent the carrier from being tricked, which could lead to mission failure or loss of control of the carrier.

[0049] It should be noted that anti-spoofing technology for satellite navigation has always been one of the most challenging and key technologies in the field of satellite navigation applications. Traditional spoofing detection methods based on satellite navigation signals (such as abnormal satellite detection and signal-to-noise ratio mutation analysis) are not sensitive enough to complex spoofing signals. This application proposes an anti-spoofing algorithm based on the trend characteristics of inertial navigation and satellite navigation trajectories, combined with dynamic threshold adjustment and a multi-level defense response mechanism, to achieve high-sensitivity and low-false-alarm-rate satellite navigation spoofing detection.

[0050] The satellite navigation anti-spoofing algorithm based on trend feature extraction provided in this application has the following key points: Trend feature extraction method: Construct a three-dimensional local vector based on inertial navigation pure inertial positioning data and satellite navigation positioning data within a sliding window, and characterize the local trend features of the two trajectories through cosine similarity; Dynamic threshold adjustment mechanism: The detection threshold is adjusted in stages according to the carrier velocity of the inertial navigation pure inertial measurement; satellite navigation deception alarm and navigation source output are performed.

[0051] This application is a software technology implementation scheme. The software inputs are the pure inertial positioning signal of the time-synchronized inertial navigation device and the satellite positioning signal output by the satellite receiver. The output is an alarm signal indicating that the satellite navigation has been spoofed.

[0052] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A satellite navigation anti-spoofing method based on dynamic trend characteristics, characterized in that, The method includes: Step 1: Collect samples separately Inertial navigation pure inertial positioning signal at all times and satellite positioning signals ; Step 2: Utilize short-time windows respectively All inertial navigation pure inertial positioning signals within a time period and satellite positioning signals Construct two sliding window arrays: Step 3, with Pure inertial positioning signal measured by inertial navigation at time 10:00 and satellite positioning signals Establish two North-East-Ground coordinate systems with the origin as the coordinate origin; Step 4: Calculate the short-time window arrays for both the inertial navigation pure inertial positioning signal and the satellite navigation positioning signal. The positioning signal and the origin of the spatial coordinate system within the short time window The three-dimensional spatial vector between the location signals at any given time; Step 5: Calculate the cosine similarity based on the three-dimensional spatial vectors; Step 6: Determine and dynamically adjust the threshold, and output an alarm based on the threshold.

2. The method according to claim 1, characterized in that, Step 1 further includes: Timestamp synchronization ensures that the inertial navigation pure inertial positioning signal is aligned with the satellite navigation positioning signal.

3. The method according to claim 2, characterized in that, Step 2 includes: The input signal frequency is set to 10Hz, meaning a position signal will be acquired every 100ms. The total duration of the constructed sliding window is... ; Utilizing all inertial navigation pure inertial positioning signals within a short time window and satellite positioning signals Two sliding window arrays can be constructed separately: This array is dynamically updated as new time-of-flight data is input, short window The duration needs to be adjusted according to the motion characteristics of the carrier.

4. The method according to claim 3, characterized in that, Step 4 includes: Based on the WGS-84 model, the three-dimensional spatial vector between the last point in the short-time window array of the inertial navigation pure inertial positioning signal and the satellite navigation positioning signal and the origin of the spatial coordinate system, i.e., the first point in the short-time window, is calculated respectively.

5. The method according to claim 4, characterized in that, The calculation of the three-dimensional spatial vector between the last point in the short-time window array of the inertial navigation pure inertial positioning signal and the satellite navigation positioning signal, based on the WGS-84 model, and the origin of the spatial coordinate system, i.e., the first point in the short-time window, includes: Taking the Earth's radius as a fixed value of 6,371,288, the distance from the origin of the spatial coordinate system of the satellite navigation positioning location to the Earth's center is: ; Northward coordinate difference between two points That is: ; Eastward coordinate difference correction amount for: ; Eastward coordinate difference between two points for: ; Difference between ground coordinates of two points for: ; The final three-dimensional spatial vector of the satellite positioning signal is ; Similarly, the three-dimensional spatial vector of the inertial navigation positioning signal is: .

6. The method according to claim 5, characterized in that, Step 5 includes: If satellite navigation signals are spoofed, their positioning results will deviate. The actual trajectory trend of a moving vehicle will inevitably differ from the satellite navigation positioning trajectory trend. However, within a short timeframe, the inertial navigation (INS) pure positioning signal can accurately represent the vehicle's true motion trend. Therefore, when satellite navigation is spoofed, the INS pure positioning trajectory vector and the satellite navigation positioning trajectory vector will inevitably have a certain angle, meaning their trajectory vector trends will be inconsistent. (Cosine similarity) The directional similarity between two vectors can be quantitatively measured, and the calculation formula is as follows: The range of cosine similarity is [-1, 1], where 1 indicates that the directions are completely consistent, 0 indicates that the directions are orthogonal and have no correlation, and -1 indicates that the directions are completely opposite.

7. The method according to claim 6, characterized in that, The threshold determination and dynamic adjustment include: The velocity information output by the pure inertial navigation positioning signal has high reliability and is not affected by external interference or deceptive signals. Therefore, the total velocity of the carrier can be calculated using the velocity signal output by the pure inertial navigation positioning signal. The maneuverability of the satellite-guided vehicle is determined by its total speed; To avoid the inability to calculate cosine similarity when the carrier is stationary, the carrier's speed must be greater than or equal to... Therefore, based on the total flight speed and division-to-zero protection, different trend detection thresholds are adopted as follows: 。 8. The method according to claim 7, characterized in that, The alarm output based on the threshold includes: Alarm signal: When If an alarm signal is sent, the flight control system can switch to pure INS navigation mode to prevent the carrier from being tricked, which could lead to mission failure or loss of control of the carrier.

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