A Beidou navigation signal deception detection method and system based on electromagnetic odometer

Abstract

The present invention relates to the technical field of navigation systems and provides a Beidou navigation signal deception detection method and system based on an electromagnetic speed log. The method comprises collecting water speed output by the electromagnetic speed log, heading output by an inertial navigation device, ship's initial latitude, ship's initial longitude, and Beidou navigation system data and performing a rationality check; constructing a ship dead reckoning model based on the water speed and heading, calculating the ship's position based on the ship's initial latitude, ship's initial longitude, and the ship dead reckoning model; calculating the ship's position under Beidou navigation based on Beidou navigation system data; calculating the Beidou navigation system positioning error based on the ship's position and the ship's position under Beidou navigation; calculating a position deviation threshold based on the water speed; and detecting Beidou navigation signal deception based on the Beidou navigation system positioning error and the error threshold. The present invention utilizes the water speed of the electromagnetic speed log to significantly improve the accuracy of detecting Beidou navigation signal deception.

Description

Technical Field

[0001] The present invention relates to the technical field of navigation systems, and in particular to a Beidou navigation signal deception detection method and system based on an electromagnetic odometer. Background Art

[0002] The electromagnetic speedometer is an instrument based on the principle of electromagnetic induction. It calculates the speed of a ship by measuring the induced electromotive force generated by the relative motion of the ship's speed and the water flow. It has the characteristics of high precision, stable operation in complex electromagnetic environments, and a wide range of adaptability.

[0003] Satellite navigation technology uses navigation satellites to provide navigation and positioning for users on the ground, at sea, in the air, and in space. Satellite navigation systems are currently a key means of obtaining spatiotemporal information. The Beidou satellite navigation system provides users with high-precision, highly reliable positioning, navigation, and timing services around the clock, in all weather conditions, worldwide. The Beidou navigation system utilizes passive positioning, achieving performance comparable to GPS and supporting unique short message communication services. However, in complex operating environments, Beidou navigation signals are susceptible to various interferences, causing system failures such as sudden mutations, which can be exploited to spoof and interfere with the Beidou navigation system. Summary of the Invention

[0004] The present invention aims to address at least one of the technical problems existing in the related art. To this end, the present invention provides a Beidou navigation signal spoofing detection method and system based on an electromagnetic speed log. This method uses the water velocity output by the electromagnetic speed log and the heading information provided by the inertial navigation device to infer the ship's position. This is used as the true value for comparison with the position information received by the Beidou navigation system, effectively increasing the probability of detecting Beidou navigation signal spoofing interference. Through a detailed rationality range check mechanism, erroneous information can be accurately eliminated, ensuring the reliability of the detection data and stably and accurately determining whether the Beidou navigation signal has been spoofed or interfered with.

[0005] The present invention provides a Beidou navigation signal deception detection method based on an electromagnetic odometer, comprising:

[0006] S1: Collect the water speed output by the electromagnetic speed log, the heading output by the inertial navigation equipment, the ship's initial latitude, the ship's initial longitude, and the Beidou navigation system data and perform a rationality check;

[0007] S2: Build a dead reckoning model for the ship based on the water speed and heading, and calculate the ship's position based on the ship's initial latitude, initial longitude, and the dead reckoning model;

[0008] S3: Calculate the ship position under Beidou navigation based on Beidou navigation system data;

[0009] S4: Calculate the positioning error of the Beidou navigation system based on the ship position and the ship position under Beidou navigation;

[0010] S5: Calculate the position deviation threshold according to the water speed;

[0011] S6: Detect Beidou navigation signal according to Beidou navigation system positioning error and error threshold.

[0012] According to the present invention, a Beidou navigation signal deception detection method based on an electromagnetic odometer further includes step S2:

[0013] S21: Decompose the water speed into the north speed and the east speed;

[0014] S22: Calculate the change in ship latitude based on the northward speed through the water;

[0015] S23: Calculate the change in longitude of the ship based on the eastward speed through the water;

[0016] S24: Calculate the ship's position based on the change in the ship's latitude and the change in the ship's longitude.

[0017] According to a Beidou navigation signal deception detection method based on an electromagnetic odometer provided by the present invention, the method further includes step S24, where the calculation expression of the ship position is:

[0018]

[0019]

[0020] in, is the latitude of the ship's position, is the initial latitude, is the change in ship latitude, is the longitude of the ship's position, is the initial longitude, is the change in ship longitude.

[0021] According to a Beidou navigation signal deception detection method based on an electromagnetic odometer provided by the present invention, the method further includes step S3, where the ship position calculation expression under Beidou navigation is:

[0022]

[0023]

[0024] in, is the Beidou navigation latitude, is the latitude measurement value of the Beidou navigation system, is the latitude measurement error term, is the standard deviation of Beidou navigation measurement error, is the longitude of Beidou navigation, is the longitude measurement value of the Beidou navigation system, is the longitude measurement error term.

[0025] According to a Beidou navigation signal deception detection method based on an electromagnetic odometer provided by the present invention, the method further includes step S4, wherein the calculation expression of the Beidou navigation system positioning error is:

[0026]

[0027]

[0028] in, is the position distance deviation, is the latitude solution deviation, is the distance corresponding to unit latitude, is the deviation of longitude solution, is the distance corresponding to a unit of longitude, is the latitude of the ship's position, is the Beidou navigation latitude, is the longitude of the ship's position, This is the Beidou navigation longitude.

[0029] According to the present invention, a Beidou navigation signal deception detection method based on an electromagnetic odometer further includes step S5:

[0030] S51: Construct an error propagation model based on the water velocity to obtain the ship position error;

[0031] S52: Calculate Beidou navigation measurement error standard deviation based on Beidou navigation system data ;

[0032] S53: Based on the ship position error and Beidou navigation measurement error standard deviation and obtaining an error threshold for water velocity.

[0033] According to a Beidou navigation signal deception detection method based on an electromagnetic odometer provided by the present invention, the method further includes step S53, wherein the calculation expression of the position deviation threshold is:

[0034]

[0035] in, is the position deviation threshold, is the standard deviation of Beidou navigation measurement error, is the ship position error, is the water velocity, is the sailing time, is the scaling factor, is the speed time weight coefficient.

[0036] According to the present invention, a Beidou navigation signal deception detection method based on an electromagnetic odometer further includes: in step S6,

[0037] If the positioning error of the BeiDou navigation system is greater than the position deviation threshold, the BeiDou navigation signal is a deception primary warning. 1 second to perform a test. If the The second is a primary warning for deception, and the Beidou navigation signal is a deception signal;

[0038] If the positioning error of the Beidou navigation system is less than or equal to the position deviation threshold, it is a true signal.

[0039] According to the present invention, a Beidou navigation signal deception detection method based on an electromagnetic odometer is provided, which also includes synchronously collecting electromagnetic odometer output data, inertial navigation device output data and Beidou navigation system data using a UTC timestamp, and the rationality check includes:

[0040] The reasonable range of heading is [0°, 360°). If the heading exceeds this range, it is considered invalid. At the same time, the boundary value 360° is treated as ;

[0041] The reasonable range of water velocity is [-50,50] kn, and it is considered invalid if it exceeds this range;

[0042] The valid range of longitude value is [-180°, 180°], and the valid range of latitude value is [-90°, 90°]. Values ​​outside this range are considered invalid.

[0043] The present invention also provides a Beidou navigation signal deception detection system based on an electromagnetic odometer, which is used to execute any of the above-mentioned Beidou navigation signal deception detection methods based on an electromagnetic odometer, comprising:

[0044] An acquisition module, which is used to collect the water speed output by the electromagnetic speed log, the heading output by the inertial navigation device, the initial latitude and longitude of the ship, and the Beidou navigation system data and perform a rationality check;

[0045] a first position calculation module, configured to construct a dead reckoning model for the ship according to the water speed and the heading, and calculate the position of the ship according to the initial latitude and longitude of the ship and the dead reckoning model;

[0046] A second position calculation module, the second position calculation module is used to calculate the position of the ship under Beidou navigation according to Beidou navigation system data;

[0047] A positioning error calculation module is used to calculate the positioning error of the Beidou navigation system based on the ship position and the ship position under Beidou navigation;

[0048] A position deviation threshold calculation module, configured to calculate a position deviation threshold according to a water velocity;

[0049] The deception detection module is used to detect Beidou navigation signals based on the Beidou navigation system positioning error and the error threshold.

[0050] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0051] This method uses the water velocity output by the electromagnetic speed log and the heading information provided by the inertial navigation device to calculate the ship's position. This is used as the true value and compared with the position information received by the Beidou navigation system, effectively improving the probability of detecting Beidou navigation signal spoofing and interference. Through a detailed rationality range check mechanism, it can accurately eliminate erroneous information, ensure the reliability of the detection data, and stably and accurately determine whether the Beidou navigation signal has been spoofed or interfered with.

[0052] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] Figure 1 The present invention provides a flowchart of a Beidou navigation signal deception detection method based on an electromagnetic odometer.

[0055] Figure 2 The present invention provides a structural diagram of a Beidou navigation signal deception detection system based on an electromagnetic odometer.

[0056] Reference numerals:

[0057] 101. Acquisition module; 102. First position calculation module; 103. Second position calculation module; 104. Positioning error calculation module; 105. Position deviation threshold calculation module; 106. Deception detection module. DETAILED DESCRIPTION

[0058] To make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Obviously, the embodiments described are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0059] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0060] The following combination Figures 1 to 2 The present invention describes a Beidou navigation signal deception detection method and system based on an electromagnetic odometer.

[0061] like Figure 1 As shown, a Beidou navigation signal deception detection method based on an electromagnetic odometer includes:

[0062] S1: Collect the water speed output by the electromagnetic speed log, the heading output by the inertial navigation equipment, the ship's initial latitude, the ship's initial longitude, and the Beidou navigation system data and perform a rationality check;

[0063] The output data of the electromagnetic odometer, the output data of the inertial navigation device and the Beidou navigation system are synchronously collected using the UTC (universal time standard) timestamp. The collected data are checked for rationality and any unreasonable information is eliminated.

[0064] For heading, the reasonable range of heading is [0°, 360°). If it exceeds this range, the heading is considered invalid. At the same time, the boundary value 360° is treated as .

[0065] For water speed, the reasonable range of water speed is [-50,50]kn. If it exceeds this range, it is considered invalid.

[0066] For location information, the valid range of longitude value should be [-180°, 180°], and the valid range of latitude value should be [-90°, 90°]. Values ​​outside this range are considered invalid.

[0067] Use UTC timestamp synchronization with an error of less than or equal to ±100ms.

[0068] In some specific embodiments of the present invention, the electromagnetic speed log outputs a water speed of ,course The longitude output by the Beidou navigation system is 122.0001°, the latitude output by the Beidou navigation system is 25.0001°, the initial latitude of the ship is 25.0000°, and the initial longitude of the ship is 122.0000°.

[0069] After verification, the water speed, heading, Beidou navigation system output longitude, Beidou navigation system output latitude, ship's initial latitude and ship's initial longitude are all within a reasonable range.

[0070] S2: Build a dead reckoning model for the ship based on the water speed and heading, and calculate the ship's position based on the ship's initial latitude, initial longitude, and the dead reckoning model;

[0071] S21: Decompose the water speed into the north speed and the east speed;

[0072] The calculation expression for the north velocity of water is:

[0073]

[0074] in, is the northward speed over water, is the water velocity, For the heading, For water noise, , is the water noise variance;

[0075] The calculation expression for the eastward velocity of water is:

[0076] ,

[0077] in, is the eastward speed of the water, is the heading noise, , is the heading noise variance.

[0078] In some specific embodiments of the present invention, , ,

[0079] S22: Calculate the change in ship latitude based on the northward speed through the water;

[0080] The calculation expression of the change in ship latitude is:

[0081]

[0082] in, is the change in ship latitude, is the sailing time, is the radius of curvature of the Earth's meridian, is the initial latitude, is the radius of the major axis of the ellipsoid, is the eccentricity of the ellipsoid, , is the flatness rate;

[0083] S23: Calculate the change in longitude of the ship based on the eastward speed through the water;

[0084] The calculation expression of the change in ship longitude is:

[0085]

[0086] in, is the change in ship longitude, is the radius of curvature of the Earth's circumplex.

[0087] S24: Calculate the ship's position based on the change in the ship's latitude and the change in the ship's longitude;

[0088] The calculation expression of the ship position is:

[0089]

[0090]

[0091] in, is the latitude of the ship's position, is the longitude of the ship's position, is the initial longitude.

[0092] In some specific embodiments of the present invention, .

[0093] S3: Calculate the ship position under Beidou navigation based on Beidou navigation system data;

[0094] The calculation expression of ship position under Beidou navigation is:

[0095]

[0096]

[0097] in, is the Beidou navigation latitude, is the latitude measurement value of the Beidou navigation system, is the latitude measurement error term, is the standard deviation of Beidou navigation measurement error, is the longitude of Beidou navigation, is the longitude measurement value of the Beidou navigation system, is the longitude measurement error term.

[0098] The multipath effect is that after the Beidou signal is reflected by the surrounding objects, the receiver receives multiple path signals, resulting in errors. When the ship is sailing in a vast sea area, there are no objects around to reflect the signal, so it can be considered that there is no multipath effect. The Beidou navigation system message parameters have a built-in ionosphere algorithm model, so the ionosphere is considered to be stable, ignoring the impact of the ionosphere on the Beidou signal. Therefore, it is considered that the Beidou navigation measurement error approximately obeys the normal distribution, so the present invention as well as All obey normal distribution.

[0099] Therefore, the standard deviation of Beidou navigation measurement error can be calculated based on Beidou navigation system data. .

[0100] In some specific embodiments of the present invention, The classic value of 8m can be used.

[0101] S4: Calculate the positioning error of the Beidou navigation system based on the ship position and the ship position under Beidou navigation;

[0102] The calculation expression of the Beidou navigation system positioning error is:

[0103]

[0104]

[0105] in, is the position distance deviation, is the latitude solution deviation, is the distance corresponding to unit latitude, is the deviation of longitude solution, is the distance corresponding to a unit of longitude, is the latitude of the ship's position, is the Beidou navigation latitude, is the longitude of the ship's position, This is the Beidou navigation longitude.

[0106] The average radius of the Earth is , , the circumference of the latitude line , ,but , similarly .

[0107] S5: Calculate the position deviation threshold according to the water speed;

[0108] S51: Construct an error propagation model based on the water velocity to obtain the ship position error;

[0109] The error propagation model is:

[0110]

[0111] in, is the ship position error, is the sailing time, is the speed correlation coefficient, is the water velocity, is the error constant, is the angle correlation coefficient;

[0112] S52: Calculate Beidou navigation measurement error standard deviation based on Beidou navigation system data ;

[0113] Beidou navigation measurement error approximately obeys normal distribution, so the present invention calculates Beidou navigation measurement error standard deviation based on Beidou navigation system data .

[0114] S53: Based on the ship position error and Beidou navigation measurement error standard deviation and obtaining an error threshold for water velocity;

[0115] The calculation expression of the position deviation threshold is:

[0116]

[0117] in, is the position deviation threshold, is the standard deviation of Beidou navigation measurement error, is the scaling factor, is the speed time weight coefficient.

[0118] In some specific embodiments of the present invention, , , , , .

[0119] S6: Detect Beidou navigation signal according to Beidou navigation system positioning error and error threshold;

[0120] If the positioning error of the BeiDou navigation system is greater than the position deviation threshold, the BeiDou navigation signal is a deception primary warning. Detect once per second. If The second is a primary warning for deception, and the Beidou navigation signal is a deception signal;

[0121] If the positioning error of the Beidou navigation system is less than or equal to the position deviation threshold, it is a true signal.

[0122] In some specific embodiments of the present invention, , .

[0123] like Figure 2 As shown, a Beidou navigation signal deception detection system based on an electromagnetic odometer is used to execute the above-mentioned Beidou navigation signal deception detection method based on an electromagnetic odometer, comprising:

[0124] The acquisition module 101 is used to collect the water speed output by the electromagnetic speed log, the heading output by the inertial navigation device, the initial latitude and longitude of the ship, and the Beidou navigation system data and perform a rationality check;

[0125] The first position calculation module 102 is used to build a dead reckoning model for the ship according to the water speed and the heading, and calculate the ship's position according to the initial latitude and longitude of the ship and the dead reckoning model of the ship;

[0126] The second position calculation module 103 is used to calculate the ship position under Beidou navigation based on Beidou navigation system data;

[0127] The positioning error calculation module 104 is used to calculate the positioning error of the Beidou navigation system according to the ship position and the ship position under Beidou navigation;

[0128] The position deviation threshold calculation module 105 is used to calculate the position deviation threshold according to the water speed;

[0129] The deception detection module 106 is used to detect Beidou navigation signals based on the Beidou navigation system positioning error and the error threshold.

[0130] Through the collaborative operation of these modules, the present invention uses the water velocity output by the electromagnetic speed log and the heading information provided by the inertial navigation device to calculate the ship's position. This is used as the true value for comparison with the position information received by the Beidou navigation system, effectively improving the probability of detecting Beidou navigation signal spoofing and interference. A detailed rationality range check mechanism can accurately eliminate erroneous information, ensure the reliability of the detection data, and stably and accurately determine whether the Beidou navigation signal has been spoofed or interfered with.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A BeiDou navigation signal deception detection method based on an electromagnetic odometer, characterized in that: include: S1: Collect the water speed output by the electromagnetic speed log, the heading output by the inertial navigation equipment, the ship's initial latitude, the ship's initial longitude, and the Beidou navigation system data and perform a rationality check; S2: Build a dead reckoning model for the ship based on the water speed and heading, and calculate the ship's position based on the ship's initial latitude, initial longitude, and the dead reckoning model; S3: Calculate the ship position under Beidou navigation based on Beidou navigation system data; S4: Calculate the positioning error of the Beidou navigation system based on the ship position and the ship position under Beidou navigation; S5: Calculate the position deviation threshold according to the water speed; S51: Construct an error propagation model based on the water velocity to obtain the ship position error; The error propagation model is: in, is the ship position error, is the sailing time, is the speed correlation coefficient, is the water velocity, is the error constant, is the angle correlation coefficient; S52: Calculate Beidou navigation measurement error standard deviation based on Beidou navigation system data ; S53: Based on the ship position error and Beidou navigation measurement error standard deviation and obtaining an error threshold for water velocity; The calculation expression of the position deviation threshold is: in, is the position deviation threshold, is the standard deviation of Beidou navigation measurement error, is the scaling factor, is the speed time weight coefficient; S6: Detect Beidou navigation signal according to Beidou navigation system positioning error and error threshold.

2. The Beidou navigation signal deception detection method based on an electromagnetic odometer according to claim 1, characterized in that: In step S2, S21: Decompose the water speed into the north speed and the east speed; S22: Calculate the change in ship latitude based on the northward speed through the water; S23: Calculate the change in longitude of the ship based on the eastward speed through the water; S24: Calculate the ship's position based on the change in the ship's latitude and the change in the ship's longitude.

3. The Beidou navigation signal deception detection method based on electromagnetic odometer according to claim 1, characterized in that: In step S24, the calculation expression of the ship position is: in, is the latitude of the ship's position, is the initial latitude, is the change in ship latitude, is the longitude of the ship's position, is the initial longitude, is the change in ship longitude.

4. The Beidou navigation signal deception detection method based on electromagnetic odometer according to claim 1, characterized in that: In step S3, the calculation expression of the ship position under Beidou navigation is: in, is the Beidou navigation latitude, is the latitude measurement value of the Beidou navigation system, is the latitude measurement error term, is the standard deviation of Beidou navigation measurement error, is the longitude of Beidou navigation, is the longitude measurement value of the Beidou navigation system, is the longitude measurement error term.

5. The Beidou navigation signal deception detection method based on electromagnetic odometer according to claim 1, characterized in that: In step S4, the calculation expression of the Beidou navigation system positioning error is: in, is the position distance deviation, is the latitude solution deviation, is the distance corresponding to unit latitude, is the longitude solution deviation, is the distance corresponding to a unit of longitude, is the latitude of the ship's position, is the Beidou navigation latitude, is the longitude of the ship's position, This is the Beidou navigation longitude.

6. The Beidou navigation signal deception detection method based on electromagnetic odometer according to claim 1, characterized in that: In step S6, If the positioning error of the BeiDou navigation system is greater than the position deviation threshold, the BeiDou navigation signal is a deception primary warning. 1 second to perform a test. If the The second is a primary warning for deception, and the Beidou navigation signal is a deception signal; If the positioning error of the Beidou navigation system is less than or equal to the position deviation threshold, it is a true signal.

7. The Beidou navigation signal deception detection method based on electromagnetic odometer according to claim 1, characterized in that: The electromagnetic odometer output data, inertial navigation device output data, and BeiDou navigation system data are synchronously collected using UTC timestamps. The rationality check includes: The reasonable range of heading is [0°, 360°). If the heading exceeds this range, it is considered invalid. At the same time, the boundary value 360° is treated as ; The reasonable range of water velocity is [-50,50] kn, and it is considered invalid if it exceeds this range; The valid range of longitude value is [-180°, 180°], and the valid range of latitude value is [-90°, 90°]. Values ​​outside this range are considered invalid.

8. A BeiDou navigation signal deception detection system based on an electromagnetic odometer, characterized in that: The method for detecting Beidou navigation signal deception based on an electromagnetic odometer according to any one of claims 1 to 7 comprises: An acquisition module, which is used to collect the water speed output by the electromagnetic speed log, the heading output by the inertial navigation device, the initial latitude and longitude of the ship, and the Beidou navigation system data and perform a rationality check; a first position calculation module, configured to construct a dead reckoning model for the ship according to the water speed and the heading, and calculate the position of the ship according to the initial latitude and longitude of the ship and the dead reckoning model; A second position calculation module, the second position calculation module is used to calculate the position of the ship under Beidou navigation according to Beidou navigation system data; A positioning error calculation module is used to calculate the positioning error of the Beidou navigation system based on the ship position and the ship position under Beidou navigation; A position deviation threshold calculation module, configured to calculate a position deviation threshold according to a water velocity; The deception detection module is used to detect Beidou navigation signals based on the Beidou navigation system positioning error and the error threshold.

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