A satellite spoofing signal source localization method based on dual-antenna satellite-inertial combination.

Abstract

This application relates to a satellite deception signal source localization method based on a dual-antenna satellite-inertial combination. The method utilizes the original measurement information from a shared-clock dual-antenna GNSS receiver fixed to a dynamic carrier and the measurement information from a strapdown inertial navigation system (INS) to establish a mathematical model between the single-difference carrier phase observations between the dual-antenna stations and the position of the stationary deception signal source. It fully leverages the INS pose information during the dynamic carrier's maneuver to achieve effective correlation of the signal source's azimuth in different epoch coordinate systems, establishing a multi-epoch signal source azimuth solution model in a specific epoch coordinate system, effectively solving the problem of efficiently solving for the azimuth of deception signal sources. This method designs an efficient and accurate analytical solution to obtain the signal source's azimuth, achieving GNSS deception signal source localization capability without increasing additional hardware investment.

Description

Technical Field

[0001] This application relates to the field of satellite navigation countermeasures technology, and in particular to a method for locating satellite deception signal sources based on a dual-antenna satellite-inertial combination. Background Technology

[0002] With the full completion and operation of the BeiDou-3 system, the Global Navigation Satellite System (GNSS) can now provide global navigation users with multi-constellation, multi-frequency, and multi-type navigation observation information, resulting in a significant improvement in the performance of navigation user positioning services. However, the open structure of satellite navigation signals and the low power of ground signals make the GNSS highly susceptible to interference, causing navigation and positioning anomalies or failures for users. Thanks to the improved accuracy and enhanced embedded computing power of high-performance micro-inertial devices, the satellite / micro-inertial combined navigation method can improve the autonomous navigation performance of small unmanned dynamic vehicles under BeiDou area denial conditions. This scheme can utilize the high-precision navigation capability of the micro-inertial navigation system in a short time to effectively cope with the adverse effects of short-term GNSS suppression interference. However, the above scheme cannot cope with navigation and positioning anomalies or deviations caused by GNSS deception interference, causing the unmanned dynamic vehicle to gradually enter the deception area preset by the interference signal source, forcing the planned mission to fail. GNSS deception signal sources, typically represented by deception interference (such as generational, relay, and traction deception), have become a major threat to the safety of missions such as unmanned dynamic vehicle intelligent driving and fully automatic precision approach in recent years. It is urgent to achieve accurate detection and clear positioning of deception signal sources to ensure the reliability of user navigation.

[0003] Traditional signal source localization techniques involve intercepting interfering signals with a receiver, processing the original sampled signal to obtain observations containing signal source location information, and then establishing and solving a system of equations based on the relationship between the observations and the signal source location to achieve signal source localization. However, the localization accuracy of this method is significantly affected by the accuracy of the observation extraction, and its location calculation and parameter estimation processes are relatively independent, failing to effectively utilize the correlation between signals received from different receiving stations. This limitation leads to information loss, difficulty in correlating localization parameters, and high system sensitivity requirements. Under low signal-to-noise ratio conditions, the localization accuracy against spoofing signal sources is typically low, and may even be impossible to locate.

[0004] For unmanned dynamic vehicles, typically represented by small unmanned aerial vehicles (UAVs), certain anti-jamming measures are usually required under GNSS area denial conditions. Achieving high-precision orientation or location of spoofing signal sources is generally an effective means and fundamental condition for implementing GNSS spoofing countermeasures. On the one hand, the azimuth information of the spoofing signal source can provide accurate signal suppression azimuth for the nulling antenna, effectively eliminating the adverse effects of spoofing signals on the receiver measurement process; on the other hand, accurate signal source azimuth enables the elimination of its location point, physically eliminating the interfering signal source. To meet the azimuth source location requirements of small unmanned dynamic vehicles, it is urgent to research and design a high-precision, miniaturized, and low-cost GNSS spoofing signal source azimuth determination method based on existing airborne satellite / inertial integrated navigation systems. Summary of the Invention

[0005] Therefore, it is necessary to provide a satellite spoofing signal source localization method based on dual-antenna satellite-inertial combination to address the above-mentioned technical problems.

[0006] A method for locating satellite spoofing signal sources based on a dual-antenna satellite-inertial integrated system is proposed. This method is applicable to dynamic carriers equipped with a dual-antenna satellite-straption inertial integrated navigation system using a shared-clock dual-antenna GNSS receiver and inertial devices for GNSS spoofing signal source location. The method includes:

[0007] Synchronize the measurement data and ephemeris data of the dual-antenna GNSS receiver with a common clock.

[0008] When a GNSS spoofing signal source is detected, the dynamic carrier implements a maneuvering strategy and uses a dual-antenna satellite-stripper inertial navigation system to collect real-time inertial navigation pose data and GNSS spoofing signal measurement data.

[0009] Based on the dynamic carrier's maneuverability, real-time pose data from inertial navigation, and measurement data of GNSS spoofing signals, a multi-epoch GNSS spoofing signal source localization model is established.

[0010] The initial azimuth value of the GNSS spoofing signal source is determined by using the distance search method based on the multi-epoch GNSS spoofing signal source localization model.

[0011] Determine whether the distance between the dynamic carrier and the GNSS spoofing signal source is greater than a preset distance threshold;

[0012] If the distance is less than the preset distance threshold, the multi-epoch GNSS spoofing signal source localization model is solved numerically to obtain the precise three-dimensional location of the GNSS spoofing signal source and output it.

[0013] If the distance exceeds a preset threshold, calculate and output the two-dimensional orientation information of the GNSS signal source.

[0014] The aforementioned satellite spoofing signal source localization method based on dual-antenna satellite-inertial combination utilizes the original measurement information from a shared-clock dual-antenna GNSS receiver fixed to a dynamic carrier and the measurement information from strapdown inertial navigation to establish a mathematical model between the single-difference carrier phase observations between the dual-antenna stations and the position of the stationary spoofing signal source. It fully leverages the inertial navigation pose information during the dynamic carrier's maneuver to achieve effective correlation of the signal source's azimuth in different epoch coordinate systems, establishing a multi-epoch signal source azimuth solution model in a specific epoch coordinate system, effectively solving the problem of efficiently solving for the azimuth of spoofing signal sources. This method designs an efficient and accurate analytical solution to obtain the signal source's azimuth, endowing existing satellite / inertial navigation receivers with GNSS spoofing signal source localization capabilities without increasing additional hardware investment. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating a satellite deception signal source localization method based on a dual-antenna satellite-inertial combination in one embodiment.

[0016] Figure 2 This is a flowchart illustrating the determination of the azimuth of a BeiDou deception signal source based on a dual-antenna satellite / inertial combination in another embodiment.

[0017] Figure 3 This is a representation of the signal source position in the front-right-lower body coordinate system in another embodiment;

[0018] Figure 4 This is a schematic diagram of the dynamic carrier's O-shaped maneuver trajectory and the location line of the signal source in another embodiment;

[0019] Figure 5 A physical diagram of a GNSS spoofing signal source in another embodiment;

[0020] Figure 6 A panoramic view of the vehicle-mounted experiment and a physical image of the rooftop equipment in another embodiment.

[0021] Figure 7 This is a diagram showing the horizontal movement trajectory of the test vehicle in another embodiment;

[0022] Figure 8 This is a graph showing the change in the attitude of the test vehicle over time in another embodiment, where... Figure 8 (a) is a graph showing the pitch angle as a function of time. Figure 8 (b) is a graph showing the change of roll angle over time. Figure 8 (c) is a graph showing the change of yaw angle over time;

[0023] Figure 9 This is a graph showing the pitch angle error of the signal source under GNSS spoofing interference as a function of time during this vehicle-mounted test in another embodiment.

[0024] Figure 10 This is a graph showing the yaw angle error of the signal source under GNSS deception interference as a function of time during this vehicle-mounted test in another embodiment.

[0025] Figure 11 Here is a graph showing the change in northward positioning error over time in another embodiment;

[0026] Figure 12 Here is a graph showing the eastward positioning error over time in another embodiment;

[0027] Figure 13 This is a graph showing the change of ground positioning error over time in another embodiment. Detailed Implementation

[0028] 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.

[0029] In one embodiment, such as Figure 1 As shown, a method for locating satellite spoofing signal sources based on a dual-antenna satellite-inertial combination is provided. This method is applicable to dynamic carriers equipped with a dual-antenna satellite-strapdown inertial navigation system built using a shared-clock dual-antenna GNSS receiver and inertial devices for GNSS spoofing signal source location. The method specifically includes the following steps:

[0030] Step 100: Synchronize the measurement data and ephemeris data of the dual-antenna GNSS receiver with time.

[0031] Step 102: When the GNSS spoofing signal source is detected to be active, the dynamic carrier implements a maneuvering strategy and uses a dual-antenna satellite-stripline inertial navigation system to collect real-time inertial navigation pose data and GNSS spoofing signal measurement data.

[0032] Specifically, the dynamic carrier can be, but is not limited to, small unmanned aerial vehicles.

[0033] Upon detecting a GNSS spoofing signal source, the dynamic vehicle immediately implements a planar O-shaped or S-shaped maneuver strategy, where the vehicle's pitch and roll angles are approximately zero, while the yaw angle undergoes a large-scale, continuous variation. At this time, a shared-clock dual-antenna GNSS receiver, fixed to the vehicle, collects measurement data such as pseudorange, pseudorange rate, and carrier phase, as well as broadcast ephemeris data, broadcast from the GNSS spoofing signal source. The decoded GNSS spoofing signal data is stored in the corresponding buffer of the navigation system. The inertial navigation attitude data and dual-antenna GNSS observation data generated during the maneuver are stored in the navigation system buffer.

[0034] Step 104: Based on the dynamic carrier's maneuverability, inertial navigation real-time pose data, and GNSS spoofing signal measurement data, establish a multi-epoch GNSS spoofing signal source localization model.

[0035] Specifically, information preprocessing is performed on the GNSS spoofing signal measurement data in the GNSS spoofing data cache to determine the single-epoch dual-frequency inter-station differential carrier phase observations and the inter-station single-differential carrier phase integer ambiguity; based on the single-epoch dual-frequency inter-station differential carrier phase observations and the inter-station single-differential carrier phase integer ambiguity, a... The equation for the location of the deception signal source at any given time is used to solve the equation. Then, by using at least three different points during the dynamic carrier's planar O-shaped or S-shaped maneuver, a multi-epoch equation for the location of the deception signal source is constructed.

[0036] Step 106: Based on the multi-epoch GNSS spoofing signal source localization model, use the distance search method to determine the initial value of the azimuth of the GNSS spoofing signal source.

[0037] Step 108: Determine whether the distance between the dynamic carrier and the GNSS spoofing signal source is greater than the preset distance threshold.

[0038] Specifically, the distance between the dynamic carrier and the GNSS spoofing signal source is determined based on the initial azimuth value of the GNSS spoofing signal source and the position of the dynamic carrier. The preset distance threshold is set based on engineering experience.

[0039] It has the ability to adaptively adjust the output type of azimuth information of GNSS deception signal source. When the distance between the carrier and the deception signal source is much greater than its maneuvering range, the method outputs accurate two-dimensional azimuth information of the signal source (i.e., yaw angle and pitch angle); when the distance between the carrier and the deception signal source is comparable to its maneuvering range, the method outputs accurate three-dimensional position information of the signal source.

[0040] Step 110: If the distance is less than the preset distance threshold, the multi-epoch GNSS spoofing signal source localization model is solved by numerical calculation to obtain the precise three-dimensional location of the GNSS spoofing signal source and output it.

[0041] Step 112: If the distance is greater than the preset distance threshold, calculate and output the two-dimensional azimuth information of the GNSS spoofing signal source.

[0042] Specifically, the two-dimensional orientation information of the GNSS spoofing signal source includes: the pitch angle and yaw angle of the GNSS spoofing signal source relative to the carrier coordinate system.

[0043] This method is based on the existing dual-antenna GNSS / inertial integrated navigation system mounted on a dynamic carrier to achieve GNSS spoofing signal azimuth measurement. It makes full use of the carrier's maneuverability and inertial navigation pose information to establish a multi-epoch signal source azimuth solution model, and designs an efficient and accurate analytical solution method to obtain the signal source azimuth. This achieves the ability to locate GNSS spoofing signal sources without increasing additional hardware investment.

[0044] In the aforementioned satellite spoofing signal source localization method based on a dual-antenna satellite-inertial combination, the method utilizes the original measurement information from a shared-clock dual-antenna GNSS receiver fixed to a dynamic carrier and the measurement information from a strapdown inertial navigation system to establish a mathematical model between the single-difference carrier phase observations between the dual-antenna stations and the position of the stationary spoofing signal source. It fully leverages the inertial navigation pose information during the dynamic carrier's maneuver to achieve effective correlation of the signal source's azimuth in different epoch coordinate systems, establishing a multi-epoch signal source azimuth solution model in a specific epoch coordinate system, effectively solving the problem of efficiently solving for the azimuth of spoofing signal sources. This method designs an efficient and accurate analytical solution to obtain the signal source's azimuth, achieving GNSS spoofing signal source localization capability without increasing additional hardware investment.

[0045] In one embodiment, the setup process of the dual-antenna satellite-stretcher inertial navigation system includes: installing two GNSS antennas along the X-axis of the dynamic carrier coordinate system; wherein the first GNSS antenna is placed at the rear of the carrier and the second GNSS antenna is placed at the front of the dynamic carrier, and calibrating the baseline length between the first and second GNSS antennas. l .

[0046] Under conditions of no GNSS spoofing signal interference, the dual-antenna satellite-strapdown inertial navigation system operates in a high-precision strapdown inertial navigation mode assisted by common-clock dual-antenna GNSS measurement information. This provides real-time and accurate full-dimensional navigation information for the dynamic vehicle it is fixed to, storing the inertial measurement and attitude data of the dynamic vehicle epoch by epoch in the buffer area of ​​the dual-antenna satellite-strapdown inertial navigation system.

[0047] Inertial measurement and pose data include navigation information time, three-dimensional position, three-dimensional velocity, three-dimensional attitude angle, three-dimensional carrier angular velocity, three-dimensional carrier acceleration, and inertial navigation extrapolation time.

[0048] Specifically, under conditions free from GNSS spoofing interference (i.e., normal GNSS conditions), the system operates in a dual GNSS measurement-assisted strapdown inertial high-precision navigation mode, providing real-time and accurate position, velocity, attitude, and time information for its attached dynamic vehicle (such as a small unmanned aerial vehicle). Thus, the navigation system's buffer can store the dynamic vehicle's inertial measurement and attitude data epoch-by-epoch.

[0049] In one embodiment, the maneuver strategy in step 102 is a planar O-shaped or S-shaped maneuver strategy.

[0050] In one embodiment, the GNSS spoofing signal measurement data includes navigation information time, GNSS system number, satellite number, pseudorange at a first frequency, pseudorange rate at a first frequency, carrier phase at a first frequency, carrier-to-noise ratio at a first frequency, pseudorange at a second frequency, pseudorange rate at a second frequency, carrier phase at a second frequency, carrier-to-noise ratio at a second frequency, pseudorange at a third frequency, pseudorange rate at a third frequency, carrier phase at a third frequency, and carrier-to-noise ratio at a third frequency.

[0051] GNSS spoofing signal broadcast ephemeris data includes navigation information time, GNSS system number, satellite number, satellite clock bias parameters, and satellite orbit parameters.

[0052] In one embodiment, step 104 includes: preprocessing the measurement data of the GNSS spoofing signal to determine the single-epoch dual-frequency inter-station differential carrier phase observation and integer ambiguity; constructing a multi-epoch GNSS spoofing signal source localization model based on the single-epoch dual-frequency inter-station differential carrier phase observation and integer ambiguity at no less than three different locations during the dynamic carrier maneuver; the expression for the multi-epoch GNSS spoofing signal source localization model is:

[0053] ;

[0054] in, The position vector of the GNSS spoofing signal source at the moment the antenna receives the signal. and Provided by inertial navigation The position vectors of the first and second GNSS antennas at time points. To observe random errors, m represents the number of observation epochs, and it is required that... , i Era numbering, For the corresponding j Inter-station single-difference carrier phase integer ambiguity at the B1 frequency point of the Beidou satellite (broadcast by a deceptive signal source). for Time number is j Inter-station differential carrier phase observations of BeiDou satellite B1 frequency point, This refers to the carrier signal wavelength corresponding to the BeiDou B1 frequency point.

[0055] Specifically, in determining the integer ambiguity After that, build The equation for determining the location of the deception signal source at time t is:

[0056] ;

[0057] Among them, the GNSS spoofing signal source location vector Assuming the signal source is stationary and is an unknown quantity to be determined, then... An unknown constant vector; provided by the inertial navigation system. Position vectors of the first and second GNSS antennas at time points and All are known quantities. Using at least three different points during the carrier's planar O-shaped or S-shaped maneuver, a multi-epoch GNSS deception signal source location equation is constructed, as shown in the expression of the multi-epoch GNSS deception signal source localization model above.

[0058] In one embodiment, information preprocessing is performed on the measurement data of the GNSS spoofing signal to determine the single-epoch dual-frequency inter-station differential carrier phase observations and integer ambiguities, including: selecting... Using measurement data of GNSS spoofing signals at frequencies B1 and B3 of the BeiDou system, a set of single-epoch inter-station differential carrier phase observation equations is constructed; the expression of the single-epoch inter-station differential carrier phase observation equations is as follows:

[0059] ;

[0060] in, for Inter-station differential carrier phase observations at BeiDou satellite B3 frequency point with time number j, where subscripts 1 and 2 indicate the GNSS antenna number; and These represent the carrier signal wavelengths corresponding to the BeiDou B3 frequency point. and These are the carrier signal frequencies corresponding to the BeiDou B1 and B3 frequency points, respectively. and These are the receiver station differences in minutes corresponding to the BeiDou B1 and B3 frequency points, respectively. , These represent differential carrier phase measurement noise, respectively. and They represent the corresponding j The integer ambiguity of the inter-station single-difference carrier phase at frequencies B1 and B3 of the Beidou satellite can be quickly determined according to the document CN118859270B "Calculation Method of Integer Ambiguity of Inter-station Single-Difference Carrier Phase for Dual-Frequency Single-Epoch Single Satellite with Short Baseline" [2025-01-21]. and .

[0061] Specifically, information preprocessing is performed on the dual-antenna GNSS observation data in the GNSS spoofing data cache. (Selection) Using real-time dual-frequency dual-antenna GNSS buffer data, such as observation data from the B1 and B3 frequencies of the BeiDou system, construct inter-station differential carrier phase observations for the B1 and B3 frequencies. and The single-epoch dual-frequency inter-station differential carrier phase observation equation set is constructed as described in the above expression of the single-epoch dual-frequency inter-station differential carrier phase observation equation set.

[0062] In one embodiment, step 106 includes: taking the specific moment during the dynamic carrier planar maneuver when the baseline vector of the first GNSS antenna pointing to the second GNSS antenna points to the GNSS spoofing signal source as... epoch; based on GNSS spoofing signal sources in The yaw and pitch angles in the front-right-lower body coordinate system of the epoch dynamic carrier are used to determine the GNSS spoofing signal source. The three-dimensional position vector of the dynamic carrier in the front-right-bottom coordinate system; GNSS spoofing signal source in The expression for the three-dimensional position vector in the front-right-bottom coordinate system of the epochal dynamic carrier is:

[0063] ;

[0064] In the formula, For GNSS spoofing signal sources in Three-dimensional position vector in the front-right-bottom coordinate system of the epochal dynamic carrier and These are GNSS spoofing signal sources in Yaw and pitch angles in the epoch carrier coordinate system d The distance is the straight-line distance from the center of the dynamic carrier to the deception signal source.

[0065] When a dynamic vehicle performs a planar O-shaped or S-shaped maneuver, the GNSS spoofing signal source is... The three-dimensional position vector in the front-right-lower body coordinate system of the epoch-time dynamic carrier is transformed to the position vector in the Earth-fixed coordinate system; based on the position vector of the GNSS spoofing signal source in the Earth-fixed coordinate system and the multi-epoch GNSS spoofing signal source positioning model, an overdetermined system of equations with the straight-line distance from the center of the carrier to the spoofing signal source as the unknown is obtained; an objective function is constructed; the expression of the objective function is:

[0066] ;

[0067] in, The straight-line distance from the center of the dynamic carrier to the deception signal source d The function, for Carrier phase observations with fixed time ambiguity For calculation based on the model The time distance value is d The corresponding inter-station single-difference carrier phase prediction value; ; Indicates calculation based on the model The time distance value is d The corresponding inter-station single-difference carrier phase prediction value, i.e. and Provided by inertial navigation Direction cosine matrix at time The first GNSS antenna position vector and the position vector of the second GNSS antenna .

[0068] A one-dimensional bisection search is employed to minimize the objective function value by finding the optimal estimate of the straight-line distance from the center of the dynamic carrier to the deception signal source. This estimate is based on the optimal estimate of the straight-line distance from the center of the dynamic carrier to the deception signal source and the location of the GNSS deception signal source. The initial two-dimensional azimuth value in the front-right-lower body coordinate system of the dynamic carrier is used to determine the initial azimuth value of the GNSS spoofing signal. The signal source position in the front-right-lower body coordinate system of the dynamic carrier is represented as follows: Figure 3 As shown.

[0069] Specifically, the distance search method is used to efficiently solve the multi-epoch GNSS spoofing signal source localization model and roughly determine the initial azimuth value.

[0070] The distance search method is specifically described as follows: Let the baseline vector pointing from the first GNSS antenna to the second GNSS antenna be... During the carrier's planar O-shaped or S-shaped maneuvers The specific moment pointing to the signal source is denoted as Epoch, then the signal source is The epochal carrier front-right-bottom coordinate system (denoted as...) b Position vector in 0 system It can be expressed in rectangular coordinates as It can be expressed in polar coordinates as GNSS spoofing signal source in Three-dimensional position vector in the front-right-bottom coordinate system of the epochal dynamic carrier As mentioned above, GNSS spoofing signal sources are... The expression for the three-dimensional position vector in the front-right-bottom coordinate system of the epochal dynamic carrier is shown below. That is:

[0071] .

[0072] Assume the dynamic vehicle approximately performs a planar O-shaped or S-shaped maneuver, with constant and near-zero pitch and roll angles, and periodically varying yaw angle. A schematic diagram of the dynamic vehicle's O-shaped maneuver trajectory and the location of the signal source is shown below. Figure 4 As shown, Figure 4 The arrows at positions 1, 2, and 3 indicate the baseline vector from the first GNSS antenna to the second GNSS antenna. Considering that the distance from the carrier to the signal source is much greater than the distance the carrier travels during the yaw angle variation period, the signal source is deceived in... Era b The initial two-dimensional orientation value in the 0 system is approximately:

[0073] .

[0074] At this time, the deceptive signal source is Era b 3D position vector in the 0 system The rectangular coordinates can be expressed as:

[0075] .

[0076] The location of the deception signal source in the Earth-fixed coordinate system ( e The position vector of the system , and position vector The following constraints must be satisfied:

[0077] ;

[0078] in, express b 0 series to e The direction cosine matrix of the system is provided by the inertial navigation system; Indicates in e The first GNSS antenna was installed in the system. The three-dimensional position vector for each epoch is provided by the inertial navigation system. Substituting the above constraints into the multi-epoch GNSS spoofing signal source localization model, the model simplifies to a single unknown. d The overdetermined system of equations is in the form of:

[0079] .

[0080] Therefore, the objective function shown in the above objective function expression is designed.

[0081] The optimal solution is obtained by using a one-dimensional binary search. This minimizes the objective function expression shown above, and the distance... d The search threshold can be set to D max (An engineering experience value of 20km can be used). If the distance to the search result is not greater than...D max The initial value of the rough orientation is determined. Proceed to step 110; otherwise, proceed to step 112.

[0082] In one embodiment, step 110 includes: accurately measuring the baseline vector length between the two GNSS antennas using a total station, and transforming the baseline vector from the ground-fixed coordinate system to the front-right-lower body coordinate system of the dynamic carrier by setting an installation matrix, thereby converting the multi-epoch GNSS spoofing signal source localization model into one that includes the GNSS spoofing signal source in... The first positioning model of the three-dimensional position coordinates of the front-right-lower body coordinate system of the epochal dynamic carrier; with When the dynamic carrier performs a planar O-shaped or S-shaped maneuver, the initial azimuth value of the GNSS deception signal source is the initial position value. The first positioning model is expanded using a first-order Taylor expansion, and the least squares estimation method is used for analytical solution to obtain the precise three-dimensional position of the GNSS deception signal source.

[0083] Specifically, with As the initial position value, the first-order Taylor expansion of the multi-epoch GNSS spoofing signal source localization model expression is performed, and the least squares estimation method is used to obtain the three-dimensional precise position of the spoofing signal source. Then, it is determined whether the solution is successful. If successful, the three-dimensional position of the signal source is directly output if the observation results are of good quality. If the observation quality is poor or the geometric configuration is bad, it may lead to three-dimensional positioning failure. In this case, it is necessary to reduce to two-dimensional orientation determination. If unsuccessful, proceed to step 112.

[0084] The least-squares analytical solution method for the three-dimensional position of the designed signal source is described below. The baseline vector length is obtained by precise prior measurement using a total station. And by setting the installation matrix, the baseline vector can be... In the carrier's "front-right-bottom" coordinate system, it is represented as The expression for the multi-epoch GNSS spoofing signal source localization model is transformed into:

[0085] ;

[0086] in, Represents the baseline vector exist The projection of the carrier in the "front-right-down" coordinate system at any given time can be determined based on the constraint relationship between the first GNSS antenna, the second GNSS antenna, and the carrier. ; Indicated by inertial navigation time e ties b i The direction cosine matrix of the system.

[0087] Still utilizing dynamic carrier planar O-shape or S-shaped maneuver Specific to the signal source Epoch, the signal source in the epoch carrier's "front-right-bottom" volume coordinate system (denoted as...) b Position vector in 0 system It can be expressed in rectangular coordinates as , Era b 0 series to e The direction cosine matrix of the system is Then the expression for the first localization model is:

[0088] ;

[0089] in, for The first GNSS antenna at that moment b The position vector in the 0 system can be provided by the inertial navigation system. The first GNSS antenna at that moment e Position vector in the system and direction cosine matrix Obtained through conversion, i.e. Therefore, the unknowns in the expression of the first localization model only include the signal source in... Era b 0-series position coordinates .when Furthermore, when the geometry of the system of equations is good, the unknowns of the system of equations are... It can be solved.

[0090] Using existing initial position values Performing a first-order Taylor expansion on the expression of the first localization model yields the first linearized system of equations:

[0091] ;

[0092] The unknowns are 3×1 matrices, i.e. ; The observable is represented by an m×1 matrix; express m The observation design matrix is ​​a 3×3 dimension, and the first element of the observation design matrix is... i Each block matrix is ​​a 1×3 matrix; Let be the random error quantity, and be an m×1 matrix. The th of the observation... i The element and the observation design matrix of the first element i The block matrices are as follows:

[0093] ;

[0094] ;

[0095] in, For the first observation i One element, The first matrix designed for observation i A block matrix.

[0096] Solving the first linearized system of equations using the least squares method yields an estimate of the error of the unknown parameters. and its variance matrix as follows:

[0097] ;

[0098] in, Let be the standard deviation of the inter-station single-difference carrier phase measurement. Then the precise three-dimensional location of the GNSS spoofing signal source is:

[0099] ;

[0100] in, To pinpoint the precise three-dimensional location of the GNSS spoofing signal source.

[0101] By designing and implementing specific maneuvering strategies for the carrier (such as S-shaped or O-shaped), this method uses dual-antenna ultra-short baseline (<1m) measurement data to construct a multi-epoch signal source orientation solution model in a specific epoch coordinate system, and uses inertial navigation pose information to achieve effective correlation of signal source orientation in different epoch coordinate systems, thereby achieving efficient solution of signal source orientation.

[0102] In one embodiment, the process of calculating the two-dimensional azimuth information of a GNSS spoofing signal source includes: based on The three-dimensional position vector of the signal source in the front-right-bottom coordinate system of the epochal dynamic carrier The polar coordinate form is used to transform the multi-epoch GNSS spoofing signal source localization model, resulting in a model containing... b The second positioning model of the yaw and pitch angles of the GNSS deception signal source in the 0 series; the GNSS deception signal source when the dynamic vehicle performs planar O-shaped or S-shaped maneuvers. The approximate initial value of the two-dimensional azimuth in the front-right-lower body coordinate system of the epoch dynamic carrier is taken as the initial value. The second positioning model is expanded by first-order Taylor expansion to obtain a linearized system of equations. The linearized system of equations is solved by the least squares method to obtain the accurate two-dimensional azimuth information of the GNSS spoofing signal source. The accurate two-dimensional azimuth information of the GNSS spoofing signal source includes the yaw angle and pitch angle of the GNSS spoofing signal source relative to the front-right-lower body coordinate system of the dynamic carrier.

[0103] Specifically, the least squares analytical solution method for the two-dimensional azimuth of the signal source is adopted to obtain the pitch angle and yaw angle of the signal source direction relative to the carrier coordinate system, i.e., the two-dimensional azimuth. It is then determined whether the solution is successful. If it is, the two-dimensional azimuth of the signal source is output. If it is unsuccessful, it is necessary to continuously accumulate observation data during the maneuver process. After the solvability of the positioning model is improved, the process returns to step 102.

[0104] The analytical solution method for the two-dimensional azimuth of the designed signal source using least squares is described below. The baseline vector length is obtained beforehand through precise measurement using a total station. And by setting the installation matrix, the baseline vector can be... In the carrier's "front-right-bottom" coordinate system, it is represented as With the help of Era b Three-dimensional position vector of the signal source in the 0 system polar coordinates The multi-epoch GNSS spoofing signal source localization model expression is transformed into one that includes... b A second positioning model for the yaw and pitch angles of a deceptive signal source in the 0 series; the expression for the second positioning model is:

[0105] ;

[0106] Where α and β are b In the 0 series, the yaw and pitch angles of the deceptive signal source; after the integer ambiguity is correctly fixed, Given the observed quantities; direction cosine matrix and All matrices are known matrices provided by the inertial navigation system. At this point, after combining the multi-epoch equations, the number of independent observations is m, and the number of independent unknowns is 2. When Furthermore, when the geometry is good, the unknowns of the equation system are... It can be solved.

[0107] Using GNSS to deceive signal sources Era b Initial values ​​of two-dimensional orientation in the 0 system By performing a first-order Taylor expansion on the expression of the second localization model, we obtain the second linearized system of equations:

[0108] ;

[0109] in, The unknown quantity is a 2×1 matrix; The observable is an m×1 matrix; Design a matrix for m×2 dimensional observations; Let be the random error quantity, which is an m×1 matrix; where and It can be represented as:

[0110] ;

[0111] ;

[0112] in, For observation The i One element, The elements of the observation design matrix.

[0113] Solving the second linearized system of equations using the least squares method yields an estimate of the error of the unknown parameters. and its variance matrix as follows

[0114] ;

[0115] In the formula, Let be the standard deviation of the inter-station single-difference carrier phase measurement. Then the precise two-dimensional orientation of the signal source is:

[0116] ;

[0117] in, To provide the precise two-dimensional orientation of the signal source.

[0118] 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.

[0119] In a verification embodiment, a vehicle-mounted test was conducted in an open area to verify the localization of GNSS spoofing signal sources. A stationary GNSS spoofing signal source was set up near the test site, such as... Figure 5 As shown. The test vehicle is equipped with a dual-antenna GNSS / micro-inertial integrated navigation system and a high-precision pose reference POS system as test equipment, such as... Figure 6As shown in the figure. The dual-antenna GNSS / micro inertial navigation system on the test vehicle uses the Sinan K825 OEM board to measure multi-frequency GNSS observation data and spoofing data. The micro inertial navigation uses the Hunan Tianyi EIMU 630 micro inertial measurement unit to acquire inertial measurement data. The high-precision pose reference POS system uses the MP-POS620 system. The key performance indicators of the relevant equipment are shown in Tables 1 to 3.

[0120] Table 1. Performance parameters of Sinan K825 board

[0121]

[0122] Table 2. Noise parameters of EIMU630 IMU

[0123]

[0124] Table 3. Performance Parameters of MP-POS620

[0125]

[0126] During the vehicle-mounted test, the GNSS deception signal source generated deception against the test vehicle at a distance of approximately 100m. The test vehicle performed an O-shaped maneuver with a horizontal movement of approximately 20m. During the maneuver, the GNSS deception signal source operated intermittently (i.e., the deception source was inactive from 0s to 300s after the start of the test and active from 300s to 600s). When the GNSS deception source was inactive, the vehicle-mounted dual-antenna GNSS / micro-inertial integrated navigation system was in a high-precision satellite / inertial information fusion state, and the inertial navigation system was effectively calibrated, providing high-precision position, velocity, and attitude data of the vehicle. After the GNSS deception source was active, the vehicle-mounted dual-antenna GNSS / micro-inertial integrated navigation system degraded to pure inertial navigation, simultaneously measuring GNSS deception signal data and inertial measurement data to achieve signal source localization. Raw observation information from the dual-antenna GNSS receiver and the inertial measurement unit (IMU) was collected throughout the experiment. The onboard high-precision POS system provided the test vehicle with a standard trajectory for post-experiment evaluation. The horizontal trajectory of the test vehicle throughout the entire experiment is shown below. Figure 7 The curve of the test vehicle's attitude changing over time is as follows: Figure 8 As shown, where Figure 8 (a) is a graph showing the pitch angle as a function of time. Figure 8 (b) is a graph showing the change of roll angle over time. Figure 8 (c) is a graph showing the change of yaw angle over time.

[0127] The curve showing the change in the two-dimensional azimuth estimation error of the signal source under GNSS spoofing interference over time during this vehicle-mounted test is as follows: Figure 9 , Figure 10 As shown, Figure 9 The curve shows the pitch angle error as a function of time. Figure 10 The curve shows the yaw angle error as a function of time. The curve shows the 3D position estimation error as a function of time. Figures 11 to 13 As shown, Figure 11 This is a curve showing the change in northward positioning error over time. Figure 12 This is a curve showing the change in eastward positioning error over time. Figure 13 This is a curve showing the change in geolocation error over time. From... Figures 9 to 13 As can be seen, the two error curves remain basically within a certain error limit, indicating that both methods can effectively determine the location of the deceptive signal source. The maximum error statistics for signal source location determination during the vehicle-mounted test are shown in Table 4. The vehicle-mounted test results show that when the distance between the vehicle and the deceptive signal source is much greater than the vehicle's maneuvering range, the maximum errors in the signal source's heading and pitch angles are both better than 2°, verifying the feasibility of the proposed method. When the distance from the deceptive signal source to the vehicle is comparable to the vehicle's maneuvering range, the maximum errors in all directions of the signal source's three-dimensional position are better than 5m, verifying the effectiveness of the proposed method. It should be noted that a 5m positioning error at a distance of 100m is equivalent to approximately 2.9° yaw angle error, indicating that the three-dimensional positioning method for the signal source exhibits superior accuracy performance under the conditions of this test. The reason for this is that the distance between the test vehicle and the deceptive signal source during the entire test was limited to no more than 200m due to the limitations of the test site. This makes a three-dimensional position determination method more suitable. If a two-dimensional orientation determination method is forcibly used at this time, the orientation of the signal source will show low accuracy. This theoretical expectation is consistent with the above test results, which to some extent verifies the rationality of the proposed method.

[0128] Table 4. Statistics on the maximum error in determining the location of deceptive signal sources

[0129]

[0130] 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.

[0131] 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 the 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.

Claims

1. A method for locating satellite spoofing signal sources based on a dual-antenna satellite-inertial combination, characterized in that, The method is applicable to the localization of GNSS spoofing signal sources on dynamic carriers equipped with a dual-antenna GNSS receiver and inertial devices. The method includes: Synchronize the measurement data and ephemeris data of the dual-antenna GNSS receiver with a common clock; When a GNSS spoofing signal source is detected to be active, the dynamic carrier implements a maneuvering strategy and uses a dual-antenna satellite-stripline inertial navigation system to collect real-time inertial navigation pose data and GNSS spoofing signal measurement data. Based on the dynamic vehicle's maneuverability, real-time inertial navigation pose data, and GNSS spoofing signal measurement data, a multi-epoch GNSS spoofing signal source localization model is established. Specifically, this includes: preprocessing the GNSS spoofing signal measurement data to determine the single-epoch dual-frequency inter-station differential carrier phase observations and integer ambiguities; and constructing a multi-epoch GNSS spoofing signal source localization model based on the single-epoch dual-frequency inter-station differential carrier phase observations and integer ambiguities at at least three different locations during the dynamic vehicle's maneuver. The multi-epoch GNSS spoofing signal source localization model is as follows: in, The position vector of the GNSS spoofing signal source at the moment the antenna receives the signal. and Provided by inertial navigation The position vectors of the first and second GNSS antennas at time points. To observe random errors, m Indicates the number of observed epochs. i Era numbering, for Time number is j Inter-station differential carrier phase observations of BeiDou satellite B1 frequency point, For the corresponding j Inter-station single-difference carrier phase integer ambiguity at the B1 frequency point of the Beidou satellite. This corresponds to the carrier signal wavelength of the BeiDou B1 frequency point; The initial azimuth value of the GNSS deception signal source is determined by using the distance search method based on the multi-epoch GNSS deception signal source localization model. Determine whether the distance between the dynamic carrier and the GNSS spoofing signal source is greater than a preset distance threshold; If the distance is less than a preset distance threshold, the multi-epoch GNSS spoofing signal source localization model is solved numerically to obtain the precise three-dimensional position of the GNSS spoofing signal source, and the result is output. Specifically, this includes taking the specific moment when the baseline vector of the first GNSS antenna pointing to the second GNSS antenna points to the GNSS spoofing signal source during the dynamic carrier's planar maneuver as the reference point. Ephemeris; The baseline vector length between two GNSS antennas is accurately measured using a total station, and by setting an installation matrix, the baseline vector is transformed from the ground-fixed coordinate system to the front-right-lower body coordinate system of the dynamic carrier. This transforms the multi-epoch GNSS spoofing signal source localization model into one that includes the GNSS spoofing signal source in... The first positioning model of the three-dimensional position coordinates of the front-right-lower body coordinate system of the epochal dynamic carrier; with When the dynamic carrier performs planar O-shaped or S-shaped maneuvers, the initial azimuth value of the GNSS deception signal source is the initial position value. The first positioning model is expanded by first-order Taylor expansion, and the least squares estimation method is used for analytical solution to obtain the three-dimensional precise position of the GNSS deception signal source. If the distance exceeds a preset threshold, calculate and output the two-dimensional orientation information of the GNSS signal source.

2. The satellite spoofing signal source localization method based on dual-antenna satellite-inertial combination according to claim 1, characterized in that, The construction process of a dual-antenna satellite-stripper inertial navigation system includes: Two GNSS antennas are installed along the X-axis of the dynamic carrier coordinate system; the first GNSS antenna is placed at the rear of the carrier and the second GNSS antenna is placed at the front of the dynamic carrier, and the baseline length between the first GNSS antenna and the second GNSS antenna is calibrated. Under conditions of no GNSS spoofing signal interference, the dual-antenna satellite-strap-inertial integrated navigation system is in a high-precision strapdown inertial navigation mode assisted by common-clock dual-antenna GNSS measurement information, providing real-time and accurate full-dimensional navigation information for the dynamic carrier it is fixed to, and storing the inertial measurement and pose data of the dynamic carrier epoch by epoch in the buffer area of ​​the dual-antenna satellite-strap-inertial integrated navigation system. The inertial measurement and pose data include navigation information time, three-dimensional position, three-dimensional velocity, three-dimensional attitude angle, three-dimensional carrier angular velocity, three-dimensional carrier acceleration, and inertial navigation extrapolation time.

3. The satellite spoofing signal source localization method based on dual-antenna satellite-inertial combination according to claim 1, characterized in that, The maneuvering strategy is a planar O-shaped or S-shaped maneuvering strategy.

4. The satellite spoofing signal source localization method based on dual-antenna satellite-inertial combination according to claim 1, characterized in that, The GNSS spoofing signal measurement data includes navigation information time, GNSS system number, satellite number, pseudorange at the first frequency, pseudorange rate at the first frequency, carrier phase at the first frequency, carrier-to-noise ratio at the first frequency, pseudorange at the second frequency, pseudorange rate at the second frequency, carrier phase at the second frequency, carrier-to-noise ratio at the second frequency, pseudorange at the third frequency, pseudorange rate at the third frequency, carrier phase at the third frequency, and carrier-to-noise ratio at the third frequency. GNSS spoofing signal broadcast ephemeris data includes navigation information time, GNSS system number, satellite number, satellite clock bias parameters, and satellite orbit parameters.

5. The satellite spoofing signal source localization method based on dual-antenna satellite-inertial combination according to claim 1, characterized in that, Information preprocessing is performed on the measurement data of GNSS spoofing signals to determine the single-epoch dual-frequency inter-station differential carrier phase observations and integer ambiguities, including: Select Based on the measurement data of GNSS spoofing signals at frequencies B1 and B3 of the BeiDou system, the following set of equations for single-epoch dual-frequency inter-station differential carrier phase observations is constructed: in, and for Time number is j The differential carrier phase observations between stations at the B1 and B3 frequencies of the BeiDou satellites, with subscripts 1 and 2 indicating the GNSS antenna numbers; and These represent the carrier signal wavelengths corresponding to the BeiDou B3 frequency point. and These are the carrier signal frequencies corresponding to the BeiDou B1 and B3 frequency points, respectively. and These are the inter-station difference in minutes for receivers corresponding to BeiDou B1 and B3 frequencies, respectively. and They are respectively the corresponding j Inter-station single-difference carrier phase integer ambiguity of Beidou satellites at frequency points B1 and B3. , They represent the corresponding j Inter-station differential carrier phase measurement noise at frequencies B1 and B3 of the Beidou satellite.

6. The satellite spoofing signal source localization method based on dual-antenna satellite-inertial combination according to claim 1, characterized in that, Based on the multi-epoch GNSS spoofing signal source localization model, the distance search method is used to determine the initial azimuth value of the GNSS spoofing signal source, including: The specific moment when the baseline vector of the first GNSS antenna pointing to the second GNSS antenna points to the GNSS spoofing signal source during the dynamic vehicle planar maneuver will be used as... Era; According to the GNSS spoofing signal source The yaw and pitch angles in the front-right-lower body coordinate system of the epoch dynamic carrier are used to determine the GNSS spoofing signal source. Three-dimensional position vector in the front-right-bottom coordinate system of the epochal dynamic carrier; In the formula, For GNSS spoofing signal sources in Three-dimensional position vector in the front-right-bottom coordinate system of the epochal dynamic carrier and These are GNSS spoofing signal sources in Yaw and pitch angles in the epoch carrier coordinate system d The straight-line distance from the center of the dynamic carrier to the deceptive signal source; When a dynamic vehicle performs a planar O-shaped or S-shaped maneuver, the GNSS spoofing signal source is... Transform the three-dimensional position vector in the front-right-lower body coordinate system of the dynamic carrier into the position vector in the Earth-fixed coordinate system; Based on the position vector of the GNSS deception signal source in the Earth-fixed coordinate system and the multi-epoch GNSS deception signal source positioning model, an overdetermined set of equations with the straight-line distance from the center of the carrier to the deception signal source as the unknown is obtained. Construct an objective function; the objective function is: in, The straight-line distance from the center of the dynamic carrier to the deception signal source d The function, for Carrier phase observations with fixed time ambiguity For calculation based on the model The time distance value is d The corresponding inter-station single-difference carrier phase prediction value; A one-dimensional bisection search is used to obtain the optimal estimate of the straight-line distance from the carrier center to the deception signal source that minimizes the objective function value. Based on the optimal estimate of the straight-line distance from the carrier center to the deception signal source and the GNSS deception signal source in The initial two-dimensional azimuth value in the front-right-bottom coordinate system of the epoch dynamic carrier is used to determine the initial azimuth value of the GNSS deception signal.

7. The satellite spoofing signal source localization method based on dual-antenna satellite-inertial combination according to claim 1, characterized in that, The process of calculating the two-dimensional azimuth information of a GNSS spoofing signal source includes: according to The polar coordinate form of the three-dimensional position vector of the signal source in the front-right-bottom coordinate system of the epochal dynamic carrier is used to transform the multi-epoch GNSS spoofing signal source localization model, resulting in a model containing... b A second positioning model for the yaw and pitch angles of a deceptive signal source in the 0 series; GNSS spoofing signal sources when a dynamic vehicle performs planar O-shaped or S-shaped maneuvers The approximate value of the initial two-dimensional orientation in the front-right-lower body coordinate system of the epochal dynamic carrier is the initial value. The second positioning model is expanded by first-order Taylor expansion to obtain a linearized system of equations. The linearized equations are solved using the least squares method to obtain the precise two-dimensional azimuth information of the GNSS spoofing signal source. The precise two-dimensional azimuth information of the GNSS spoofing signal source includes the yaw angle and pitch angle of the GNSS spoofing signal source relative to the front-right-lower body coordinate system of the dynamic vehicle.

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