Satellite navigation decoy detection method and system based on inertial navigation

Abstract

The invention discloses a satellite navigation decoy detection method based on inertial navigation, and the method comprises the steps: carrying out the validity verification of received satellite navigation data before the alignment of equipment is not completed; once the data is valid, the equipment enters a combined navigation state, and in the state, the judgment threshold values of the satellite navigation position and speed are dynamically set by utilizing the characteristic that inertial navigation errors diverge along with time; position and speed information provided by satellite navigation and inertial navigation is compared in real time, and if the difference value of the two exceeds a preset dynamic threshold value, it is judged that the satellite navigation information may be decoy; once decoy is detected, the device exits the integrated navigation state; according to the invention, satellite navigation decoy detection is realized through a software algorithm, navigation data can be judged and processed autonomously and accurately in a complex and severe navigation environment, and navigation errors caused by signal decoy are prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite navigation deception detection, and in particular to a satellite navigation deception detection method and system based on inertial navigation. Background Art

[0002] In modern navigation technology, satellite navigation systems are widely used in navigation and mapping on various platforms at sea, on land, in the air and in space due to their low cost, high accuracy, error characteristics close to white noise, and no accumulation over time. However, satellite navigation systems also have the defect that signals are easily interfered or deceived, which is particularly prominent in high-precision navigation applications, and may lead to errors in navigation information, thus affecting the accuracy and safety of navigation.

[0003] In order to ensure the reliability of satellite navigation information, various measures have been taken in the existing technology. On the one hand, satellite navigation messages usually contain a signal availability flag to indicate the validity of the signal; on the other hand, anti-interference antennas are configured to enhance signal capture and anti-interference capabilities. However, these methods mainly rely on hardware improvements and judgments, and lack a method for comprehensive judgment from the software algorithm level combined with other navigation systems.

[0004] In addition, as an autonomous navigation system, although the inertial navigation system does not rely on external signals, its error will gradually increase over time. This error characteristic makes it impossible for the traditional static threshold setting method to accurately reflect the real-time changes of inertial navigation errors when setting the detection threshold, thus affecting the accuracy of satellite navigation deception judgment. Especially during long-term navigation, the static threshold often cannot adapt to the gradual accumulation of errors, resulting in an increased risk of misjudgment or missed judgment. Summary of the invention

[0005] The purpose of the present invention is to provide a satellite navigation spoofing detection method based on inertial navigation to solve the problems existing in the prior art. Satellite navigation spoofing detection is realized through software algorithm, which can autonomously and accurately judge and process navigation data in complex and harsh navigation environments to prevent navigation errors caused by signal spoofing.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A satellite navigation deception detection method based on inertial navigation, comprising:

[0008] Before the inertial navigation system has completed alignment, the satellite navigation system receives a new frame of satellite navigation data forwarded by the flight control system and determines the validity of the satellite navigation data;

[0009] If the validity judgment is passed, the satellite navigation data is considered valid and subsequent satellite navigation anti-spoofing judgment can be carried out;

[0010] When the device completes alignment and enters the combined navigation state, it performs satellite navigation anti-spoofing judgment;

[0011] Among them, the satellite navigation anti-spoofing judgment process includes:

[0012] According to the characteristics of the inertial navigation error diverging over time, a dynamic satellite navigation position threshold and a satellite navigation speed threshold related to time are set;

[0013] Compare the satellite navigation position of the new frame with the inertial navigation position, and if the difference is greater than or equal to the satellite navigation position threshold, it is determined that the satellite navigation position information is spoofed;

[0014] Compare the satellite navigation speed with the inertial navigation speed, and if the difference is greater than or equal to the satellite navigation speed threshold, it is determined that the satellite navigation speed information is spoofed;

[0015] If the satellite navigation position and speed information are not spoofed, the combined navigation state will continue to be maintained. If any one of the satellite navigation position information and the satellite navigation speed information is spoofed, the device will exit the combined navigation state.

[0016] Satellite navigation data validity judgment, including:

[0017] Check the original satellite navigation valid identification forwarded by the flight control to confirm whether the identification is valid;

[0018] Calculate the PDOP value of the current satellite navigation data and compare it with the preset PDOP threshold. If the PDOP value is too large, the satellite navigation data is considered unreliable.

[0019] Check the satellite navigation solution status to confirm whether the position and speed information are successfully solved;

[0020] Compare the current satellite navigation information with the satellite navigation information at the previous moment to check whether there is any abnormal jump in the data;

[0021] If any of the above judgments fails, the current satellite navigation data is considered invalid and no subsequent processing is performed; if all judgments pass, the satellite navigation data is considered valid and subsequent satellite navigation anti-spoofing judgments can be performed.

[0022] According to the characteristics of inertial navigation error divergence over time, set the dynamic satellite navigation position threshold and satellite navigation speed threshold related to time, including:

[0023] Collect position and velocity data output by the inertial navigation system from actual navigation or simulation experiments;

[0024] For the speed data at each time point, compare it with the known true speed, calculate the speed error, and draw a curve of the speed error changing with time;

[0025] For the position data at each time point, compare it with the known true position, calculate the position error, and draw a curve of the position error changing with time;

[0026] According to the speed error curve and the position error curve, determine the characteristics of the speed error and the position error diverging with time;

[0027] According to the divergence characteristics of the speed and position errors of inertial navigation, the navigation time is divided into several time periods, and different speed and position judgment thresholds are set for each time period.

[0028] Divide the navigation time into several time periods and set different satellite navigation position thresholds for each time period, including:

[0029] When the navigation time is in the initial stage, that is, 0≤t0≤t1;

[0030] The satellite navigation position threshold is set to ΔP1, and the formula is as follows:

[0031]

[0032] Among them, n is the initial position error, t0 is the inertial navigation time, and a is the divergence coefficient;

[0033] When the navigation time is mid-term, that is, t1 <t0≤t2;

[0034] The satellite navigation position threshold is set to ΔP2 at this time, and the formula is as follows:

[0035]

[0036] Where b is the mid-term threshold fine-tuning constant;

[0037] When the navigation time is long, that is, t2 <t0;

[0038] The satellite navigation position threshold is set to ΔP3, and the calculation formula is as follows:

[0039]

[0040] Where c is the long-term threshold fine-tuning constant.

[0041] Divide the navigation time into several time periods and set different satellite navigation speed thresholds for each time period, including:

[0042] When the navigation time is in the initial stage, that is, 0≤t0≤t1;

[0043] The satellite navigation speed threshold is set to ΔS1, and the formula is as follows:

[0044] ΔS1=m+at0;

[0045] Where n is the initial position error, t0 is the inertial navigation time, and a is the initial divergence speed of the inertial navigation velocity error;

[0046] When the navigation time is mid-term, that is, t1 <t0≤t2;

[0047] The satellite navigation speed threshold is set to ΔS2, and the formula is as follows:

[0048]

[0049] Where d is the mid-term speed threshold fine-tuning constant;

[0050] When the navigation time is long, that is, t2 <t0;

[0051] The satellite navigation speed threshold is set to ΔS3, and the calculation formula is as follows:

[0052]

[0053] Where e is the long-term speed threshold fine-tuning constant.

[0054] The satellite navigation spoofing detection method also includes a spoofing end judgment step, which specifically includes:

[0055] When it is determined that the state has been entered into a deception state, the satellite navigation speed regression threshold and the satellite navigation position regression threshold are respectively set according to a predetermined ratio of the current satellite navigation speed threshold and the satellite navigation position threshold;

[0056] Continuously monitor the speed and position information provided by satellite navigation and compare it with the corresponding information provided by the inertial navigation system;

[0057] If the difference between the monitored satellite navigation speed and the inertial navigation speed is less than the satellite navigation speed regression threshold, and the difference between the satellite navigation position and the inertial navigation position is less than the satellite navigation position regression threshold, and lasts for a predetermined time, it is determined that the spoofing is over.

[0058] The satellite navigation spoofing detection method also includes a calibration step, specifically including:

[0059] After the deception is over, the inertial navigation system and the satellite navigation system are started simultaneously to ensure that the time of the two devices is synchronized and to collect data separately;

[0060] Compare the output data of the inertial navigation system and the satellite navigation system to determine the source and magnitude of the error;

[0061] Calibrate and adjust the parameters of the satellite navigation system based on the error analysis results;

[0062] The output data of the adjusted satellite navigation system is repeatedly checked until the data deviation between it and the inertial navigation system is within a predetermined range.

[0063] A satellite navigation deception detection system based on inertial navigation, comprising:

[0064] Inertial navigation system, used to provide position and speed information of the carrier;

[0065] Satellite navigation system, used to receive satellite signals and provide real-time position and speed information;

[0066] A threshold setting module dynamically sets the satellite navigation position threshold and the satellite navigation speed threshold according to the characteristics of the error divergence of the inertial navigation system over time;

[0067] The comparison and judgment module compares the inertial navigation position of a new frame with the satellite navigation position to determine whether the position information is spoofed, and compares the inertial navigation speed with the satellite navigation speed to determine whether the speed information is spoofed;

[0068] The state management module manages the combined navigation state according to the result of the comparison and judgment module, including maintaining the combined navigation or exiting the combined navigation.

[0069] A computer-readable storage medium stores a computer program, wherein the computer program implements the above method steps when executed by a processor.

[0070] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the above method steps are implemented when the processor executes the computer program.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] 1. By introducing inertial navigation data as a reference source, satellite navigation data is decoyed and detected. Due to the autonomy of inertial navigation, the dependence on external navigation signals is reduced. In complex or harsh navigation environments, the system can judge and process navigation data more autonomously, enhancing the autonomy and controllability of the system.

[0073] 2. Setting dynamic satellite navigation position threshold and satellite navigation speed threshold related to time accurately reflects the characteristics of inertial navigation error divergence over time and improves the accuracy of deception judgment;

[0074] 3. Through the deception end judgment step, the whole process of satellite navigation data from normal to deception and then back to normal can be fully monitored, which improves the flexibility of the system;

[0075] 4. After the deception is completed, the output data of the inertial navigation system and the satellite navigation system are compared through the calibration step to accurately determine the source and size of the error, and the satellite navigation system is calibrated and adjusted to eliminate the system error and improve the accuracy and stability of navigation. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0077] Figure 1 Schematic diagram of the principle of the satellite navigation deception detection method in the embodiment of the present application;

[0078] Figure 2 This is a schematic diagram of a process for determining the validity of satellite navigation data in an embodiment of the present application;

[0079] Figure 3 This is a flowchart of the satellite navigation anti-spoofing judgment process in the embodiment of the present application;

[0080] Figure 4 This is a graph showing the change of position error over time during multiple voyages in the embodiment of the present application;

[0081] Figure 5 This is a graph showing the speed error changing with time during multiple voyages in an embodiment of the present application. DETAILED DESCRIPTION

[0082] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0083] The size of the serial numbers of the steps in the embodiments of the present application does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0084] In the description of the present specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish descriptions and cannot be understood as indicating or suggesting relative importance. It should also be understood that although the terms "first", "second", etc. are used to describe various elements in some embodiments of the present application in the text, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, the first table can be named as the second table, and similarly, the second table can be named as the first table without departing from the scope of the various described embodiments. The first table and the second table are both tables, but they are not the same table.

[0085] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0086] In modern navigation technology, satellite navigation systems are widely used in navigation and mapping on various platforms at sea, on land, in the air and in space due to their low cost, high accuracy, error characteristics close to white noise, and no accumulation over time. However, satellite navigation systems also have the defect that signals are easily interfered or deceived, which is particularly prominent in high-precision navigation applications, and may lead to errors in navigation information, thus affecting the accuracy and safety of navigation.

[0087] In order to ensure the reliability of satellite navigation information, various measures have been taken in the existing technology. On the one hand, satellite navigation messages usually contain a signal availability flag to indicate the validity of the signal; on the other hand, anti-interference antennas are configured to enhance signal capture and anti-interference capabilities. However, these methods mainly rely on hardware improvements and judgments, and lack a method for comprehensive judgment from the software algorithm level combined with other navigation systems.

[0088] In addition, as an autonomous navigation system, although the inertial navigation system does not rely on external signals, its error will gradually increase over time. This error characteristic makes it impossible for the traditional static threshold setting method to accurately reflect the real-time changes of inertial navigation errors when setting the detection threshold, thus affecting the accuracy of satellite navigation deception judgment. Especially during long-term navigation, the static threshold often cannot adapt to the gradual accumulation of errors, resulting in an increased risk of misjudgment or missed judgment.

[0089] In response to the above problems, Figures 1 to 3 As shown, in a first aspect of an embodiment of the present application, a satellite navigation spoofing detection method based on inertial navigation is provided, comprising the following steps:

[0090] S1. Before the inertial navigation system has completed alignment, the satellite navigation system receives a new frame of satellite navigation data forwarded by the flight control system and determines the validity of the satellite navigation data;

[0091] S2. If the validity judgment is passed, the satellite navigation data is considered valid and subsequent satellite navigation anti-spoofing judgment can be performed;

[0092] S3. When the device completes alignment and enters the combined navigation state, it performs satellite navigation anti-spoofing judgment;

[0093] Among them, the satellite navigation anti-spoofing judgment process includes:

[0094] S4. According to the characteristics of the inertial navigation error diverging over time, a dynamic satellite navigation position threshold and a satellite navigation speed threshold related to time are set;

[0095] S5, comparing the satellite navigation position of the new frame with the inertial navigation position, if the difference is greater than or equal to the satellite navigation position threshold, it is determined that the satellite navigation position information is spoofed;

[0096] S6, comparing the satellite navigation speed with the inertial navigation speed, and if the difference is greater than or equal to the satellite navigation speed threshold, determining that the satellite navigation speed information is spoofed;

[0097] S7. If neither the satellite navigation position nor the speed information is spoofed, the combined navigation state is maintained; if any one of the satellite navigation position information and the satellite navigation speed information is spoofed, the device exits the combined navigation state.

[0098] In this embodiment, by introducing inertial navigation data as a reference source, spoofing detection is performed on satellite navigation data. Due to the autonomy of inertial navigation, the dependence on external navigation signals is reduced. In complex or harsh navigation environments, the system can judge and process navigation data more autonomously, thereby enhancing the autonomy and controllability of the system.

[0099] By setting dynamic satellite navigation position thresholds and satellite navigation speed thresholds that are related to time, the characteristics of the divergence of inertial navigation errors over time can be more accurately reflected, thereby improving the accuracy of satellite navigation deception judgments.

[0100] like Figure 2 As shown, in step S1, the satellite navigation data validity judgment includes:

[0101] S1.1. Check the original satellite navigation valid identification forwarded by the flight control to confirm whether the identification is valid;

[0102] S1.2. Calculate the position precision dilution PDOP value of the current satellite navigation data and compare it with the preset PDOP threshold. If the PDOP value is too large, the satellite navigation data is considered unreliable.

[0103] S1.3. Check the satellite navigation solution status to confirm whether the position and speed information are successfully solved;

[0104] S1.4. Compare the current satellite navigation information with the satellite navigation information at the previous moment to check whether there is any abnormal jump in the data;

[0105] S1.5. If any of the above judgments fails, the current satellite navigation data is considered invalid and no subsequent processing is performed; if all judgments pass, the satellite navigation data is considered valid and subsequent satellite navigation anti-spoofing judgments can be performed.

[0106] Through the steps of the above embodiment, before detecting satellite navigation data spoofing, the validity of the satellite navigation data is first judged, which can quickly identify and quickly screen out obviously abnormal or invalid data, thereby ensuring the reliability of the data entering the spoofing detection process.

[0107] In step S4, according to the characteristics of the inertial navigation error diverging over time, a dynamic satellite navigation position threshold and a satellite navigation speed threshold that are correlated with time are set, including:

[0108] S4.1. Collect position and velocity data output by the inertial navigation system from actual navigation or simulation experiments;

[0109] S4.2. For each time point, compare the speed data with the known true speed, calculate the speed error, and draw a curve of the speed error changing with time;

[0110] S4.3. For each time point, the position data is compared with the known true position, the position error is calculated, and a curve of the position error changing with time is plotted;

[0111] S4.4, determining the characteristics of the velocity error and position error diverging over time according to the velocity error curve and the position error curve;

[0112] S4.5. According to the divergence characteristics of the speed and position errors of inertial navigation, the navigation time is divided into several time periods, and different speed and position judgment thresholds are set for each time period.

[0113] Through the above embodiment steps, the velocity error curve and position error curve are obtained, which can accurately reflect the change pattern of inertial navigation error over time. The dynamic threshold set based on the change pattern can more accurately determine whether the satellite navigation data is spoofed, thereby improving the accuracy of spoofing detection.

[0114] like Figure 4 As shown in Figure 1, it is the curve of position error changing with time under multiple voyages. Figure 5 As shown in Figure 1, it is the curve of speed error changing with time under multiple voyages.

[0115] The divergence trend of inertial navigation position and velocity errors can be summarized as follows:

[0116] Within the first 15 minutes of navigation, the speed error showed a linear growth trend, which was mainly caused by factors such as sensor noise. As time went on, in the 15 to 40 minute interval, the speed error began to be affected by the Shura oscillation, and obvious oscillations appeared. The Shura oscillation is a unique error manifestation of the inertial navigation system, which is related to the rotation of the earth and the internal dynamics of the navigation system. At this stage, the oscillation of the speed error gradually increased and reached a peak. After 40 minutes, the speed error began to gradually converge back, and the accumulation of errors reached a dynamic equilibrium state. When the pure inertial navigation time exceeds 1 hour, the law of speed error becomes less obvious, and the difference between multiple voyages becomes larger.

[0117] Within the first 10 minutes of navigation, the relationship between position error and time is roughly quadratic, because the position error is the integral of the speed error, and the initial speed error grows linearly. After entering the 10 to 40 minute interval, although the position error is still growing, the divergence trend of the position error also becomes relatively slow due to the slower growth rate of the speed error. In the time period of 40 minutes to 1 hour, the divergence of the position error slows down further and gradually reaches a peak. Similar to the speed error, when the pure inertial navigation time exceeds 1 hour, the law of the position error becomes less obvious, and the difference between multiple voyages increases.

[0118] In step S4.5, the navigation time is divided into several time periods, and different satellite navigation position determination thresholds are set for each time period, including:

[0119] When the navigation time is in the initial stage, that is, 0≤t0≤t1;

[0120] The satellite navigation position threshold is set to ΔP1, and the formula is as follows:

[0121]

[0122] Among them, n is the initial position error, t0 is the inertial navigation time, and a is the initial divergence speed of the inertial navigation velocity error, which is used as the divergence coefficient;

[0123] When the navigation time is mid-term, that is, t1 <t0≤t2;

[0124] The satellite navigation position threshold is set to ΔP2 at this time, and the formula is as follows:

[0125]

[0126] Where b is the mid-term threshold fine-tuning constant;

[0127] When the navigation time is long, that is, t2 <t0;

[0128] The satellite navigation position threshold is set to ΔP3, and the calculation formula is as follows:

[0129]

[0130] Where c is the long-term threshold fine-tuning constant.

[0131] In step S4.5, the navigation time is divided into several time periods, and different satellite navigation speed judgment thresholds are set for each time period, including:

[0132] When the navigation time is in the initial stage, that is, 0≤t0≤t1;

[0133] The satellite navigation speed threshold is set to ΔS1, and the formula is as follows:

[0134] ΔS1=m+at0;

[0135] Among them, m is the initial velocity error, t0 is the inertial navigation time, and a is the initial divergence speed of the inertial navigation velocity error, which is used as the divergence coefficient;

[0136] When the navigation time is mid-term, that is, t1 <t0≤t2;

[0137] The satellite navigation speed threshold is set to ΔS2, and the formula is as follows:

[0138]

[0139] Where d is the mid-term speed threshold fine-tuning constant;

[0140] When the navigation time is long, that is, t2 <t0;

[0141] The satellite navigation speed threshold is set to ΔS3, and the calculation formula is as follows:

[0142]

[0143] Among them, e is the fine-tuning constant of the long-term speed threshold.

[0144] Exemplarily, the navigation time is divided into three time periods: the initial period, the middle period, and the long term. The initial period is set as 0 ≤ t0 ≤ 600 s, the middle period is 600 < t0 ≤ 2400 s, and the long term is t0 > 2400 s.

[0145] When the navigation time is in the initial period, that is, 0 ≤ t0 ≤ 600 s.

[0146] According to the divergence characteristic that the position error shows a quadratic function with time, the position error threshold is set as ΔP1 = 80 + 0.001t 2 。

[0147] According to the linear divergence of the speed error with time, the speed error threshold is set as ΔS1 = 0.5 + 0.002t.

[0148] When the navigation time is in the middle period, that is, 600 < t0 ≤ 2400 s.

[0149] According to the Schuler oscillation characteristic of the inertial navigation error, the position error threshold is set as ΔP2 = 180 + 0.00066t 2 , and the speed error threshold is set as ΔS2 = 1.7 + 0.0013t.

[0150] When the navigation time is in the long term, that is, t0 > 2400 s

[0151] According to the Schuler oscillation characteristic of the inertial navigation error, the position error threshold is set as a fixed value of 4000, and the speed error threshold is set as a fixed value of 4.82.

[0152] This embodiment takes into account the divergence characteristics of the inertial navigation error in different stages. By introducing the divergence coefficient a, the middle-term threshold fine-tuning constant, and the long-term threshold fine-tuning constant, the system can flexibly adjust the threshold according to the error conditions in different stages, and can better cope with various complex navigation environments and interference sources.

[0153] The satellite navigation spoofing detection method of this application further includes a spoofing end judgment step S8, which specifically includes:

[0154] S8.1. After it is determined that the spoofing state is entered, the satellite navigation speed regression threshold and the satellite navigation position regression threshold are respectively set at a predetermined ratio of the current satellite navigation speed threshold and the satellite navigation position threshold;

[0155] S8.2. Continuously monitor the speed information and position information provided by the satellite navigation, and at the same time compare them with the corresponding information provided by the inertial navigation system;

[0156] S8.3. If the difference between the monitored satellite navigation speed and the inertial navigation speed is less than the satellite navigation speed regression threshold, and the difference between the satellite navigation position and the inertial navigation position is less than the satellite navigation position regression threshold, and continues for a predetermined time, it is determined that the spoofing is over.

[0157] By setting the deception end judgment step, the whole process of satellite navigation data from normal to deception and then back to normal can be fully monitored. Not only can deception be discovered in time, but also whether the deception has ended can be accurately judged, thus improving the integrity of deception detection.

[0158] The satellite navigation spoofing detection method of the present application further includes a calibration step S9, which specifically includes:

[0159] S9.1. After the deception is completed, the inertial navigation system and the satellite navigation system are started simultaneously to ensure that the time of the two devices is synchronized and to collect data respectively;

[0160] S9.2. Compare the output data of the inertial navigation system and the satellite navigation system to determine the source and magnitude of the error;

[0161] S9.3. Calibrate and adjust the parameters of the satellite navigation system based on the error analysis results;

[0162] S9.4. Repeatedly check the output data of the adjusted satellite navigation system until its data deviation from the inertial navigation system is within a predetermined range.

[0163] After the deception is over, by comparing the output data of the inertial navigation system and the satellite navigation system, the source and size of the error can be accurately determined, and the parameters of the satellite navigation system can be calibrated and adjusted. By eliminating the system error, the accuracy of navigation is improved.

[0164] For example, after comparing the positioning data of the two systems, it was found that the positioning result of the satellite navigation system was about 10 meters north of the positioning result of the inertial navigation system. Through further analysis, it was determined that this was due to the influence of atmospheric delay on the satellite signal during transmission. According to the error analysis results, the tracking loop parameters of the satellite navigation receiver were adjusted to adapt to the change of atmospheric delay; the output data of the adjusted satellite navigation system was repeatedly checked until the positioning deviation was reduced from the original 10 meters to within 1 meter, achieving the expected calibration effect.

[0165] According to a second aspect of an embodiment of the present application, a satellite navigation spoofing detection system based on inertial navigation is provided, comprising:

[0166] Inertial navigation system, used to provide position and speed information of the carrier;

[0167] Satellite navigation system, used to receive satellite signals and provide real-time position and speed information;

[0168] A threshold setting module dynamically sets the satellite navigation position threshold and the satellite navigation speed threshold according to the characteristics of the error divergence of the inertial navigation system over time;

[0169] The comparison and judgment module compares the inertial navigation position of a new frame with the satellite navigation position to determine whether the position information is spoofed, and compares the inertial navigation speed with the satellite navigation speed to determine whether the speed information is spoofed;

[0170] The state management module manages the combined navigation state according to the result of the comparison and judgment module, including maintaining the combined navigation or exiting the combined navigation.

[0171] According to a third aspect of an embodiment of the present application, a computer-readable storage medium is provided, in which a computer program is stored. When the computer program is executed by a processor, the above-mentioned method steps are implemented.

[0172] According to a fourth aspect of an embodiment of the present application, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method steps when executing the computer program.

[0173] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A satellite navigation spoofing detection method based on inertial navigation, characterized in that: include: Before the inertial navigation system has completed alignment, the satellite navigation system receives a new frame of satellite navigation data and determines the validity of the satellite navigation data; If the validity judgment is passed, the satellite navigation data is considered valid and subsequent satellite navigation anti-spoofing judgment can be carried out; When the inertial navigation system completes alignment and enters the integrated navigation state, satellite navigation anti-spoofing judgment is performed; Among them, the satellite navigation anti-spoofing judgment process includes: According to the characteristics of the inertial navigation error diverging over time, a dynamic satellite navigation position threshold and a satellite navigation speed threshold related to time are set; Compare the satellite navigation position of the new frame with the inertial navigation position, and if the difference is greater than or equal to the satellite navigation position threshold, it is determined that the satellite navigation position information is spoofed; Compare the satellite navigation speed with the inertial navigation speed, and if the difference is greater than or equal to the satellite navigation speed threshold, it is determined that the satellite navigation speed information is spoofed; If the satellite navigation position and speed information are not spoofed, the combined navigation state will continue to be maintained. If any one of the satellite navigation position information and the satellite navigation speed information is spoofed, the device will exit the combined navigation state.

2. The satellite navigation spoofing detection method based on inertial navigation according to claim 1, characterized in that: Satellite navigation data validity judgment, including: Check the original satellite navigation valid identification forwarded by the flight control to confirm whether the identification is valid; Calculate the PDOP value of the current satellite navigation data and compare it with the preset PDOP threshold. If the PDOP value is too large, the satellite navigation data is considered unreliable. Check the satellite navigation solution status to confirm whether the position and speed information are successfully solved; Compare the current satellite navigation information with the satellite navigation information at the previous moment to check whether there is any abnormal jump in the data; If any of the above judgments fails, the current satellite navigation data is considered invalid and no subsequent processing is performed; if all judgments pass, the satellite navigation data is considered valid and subsequent satellite navigation anti-spoofing judgments can be performed.

3. The satellite navigation spoofing detection method based on inertial navigation according to claim 1, characterized in that: According to the characteristics of inertial navigation error divergence over time, set the dynamic satellite navigation position threshold and satellite navigation speed threshold related to time, including: Collect position and velocity data output by the inertial navigation system from actual navigation or simulation experiments; For the speed data at each time point, compare it with the known true speed, calculate the speed error, and draw a curve of the speed error changing with time; For the position data at each time point, compare it with the known true position, calculate the position error, and draw a curve of the position error changing with time; According to the speed error curve and the position error curve, determine the characteristics of the speed error and the position error diverging with time; According to the divergence characteristics of the speed and position errors of inertial navigation, the navigation time is divided into several time periods, and different speed and position judgment thresholds are set for each time period.

4. The satellite navigation deception detection method based on inertial navigation according to claim 3 is characterized in that: Divide the navigation time into several time periods and set different satellite navigation position thresholds for each time period, including: When the navigation time is in the initial stage, that is, 0≤t0≤t1; The satellite navigation position threshold is set to ΔP1, and the formula is as follows: Among them, n is the initial position error, t0 is the inertial navigation time, and a is the divergence coefficient; When the navigation time is mid-term, that is, t1 <t0≤t2; The satellite navigation position threshold is set to ΔP2 at this time, and the formula is as follows: Where b is the mid-term threshold fine-tuning constant; When the navigation time is long, that is, t2 <t0; The satellite navigation position threshold is set to ΔP3 at this time, and the formula is as follows: Where c is the long-term threshold fine-tuning constant.

5. The satellite navigation deception detection method based on inertial navigation according to claim 3 is characterized in that: Divide the navigation time into several time periods and set different satellite navigation speed thresholds for each time period, including: When the navigation time is in the initial stage, that is, 0≤t0≤t1; The satellite navigation speed threshold is set to ΔS1, and the formula is as follows: ΔS1=m+at0; Where, m is the initial velocity error, t0 is the inertial navigation time, and a is the initial divergence speed of the inertial navigation velocity error; When the navigation time is mid-term, that is, t1 <t0≤t2; The satellite navigation speed threshold is set to ΔS2, and the formula is as follows: Where d is the mid-term speed threshold fine-tuning constant; When the navigation time is long, that is, t2 <t0; The satellite navigation speed threshold is set to ΔS3, and the calculation formula is as follows: Where e is the long-term speed threshold fine-tuning constant.

6. The satellite navigation spoofing detection method based on inertial navigation according to claim 1, characterized in that: It also includes the steps of judging the end of deception, including: When it is determined that the state has been entered into a deception state, the satellite navigation speed regression threshold and the satellite navigation position regression threshold are respectively set according to a predetermined ratio of the current satellite navigation speed threshold and the satellite navigation position threshold; Continuously monitor the speed and position information provided by satellite navigation and compare it with the corresponding information provided by the inertial navigation system; If the difference between the monitored satellite navigation speed and the inertial navigation speed is less than the satellite navigation speed regression threshold, and the difference between the satellite navigation position and the inertial navigation position is less than the satellite navigation position regression threshold, and lasts for a predetermined time, it is determined that the spoofing is over.

7. The satellite navigation spoofing detection method based on inertial navigation according to claim 1, characterized in that: Also included are calibration steps, including: After the deception is over, the inertial navigation system and the satellite navigation system are started simultaneously to ensure that the time of the two devices is synchronized and to collect data separately; Compare the output data of the inertial navigation system and the satellite navigation system to determine the source and magnitude of the error; Calibrate and adjust the parameters of the satellite navigation system based on the error analysis results; The output data of the adjusted satellite navigation system is repeatedly checked until the data deviation between it and the inertial navigation system is within a predetermined range.

8. A satellite navigation deception detection system based on inertial navigation, characterized in that: include: Inertial navigation system, used to provide position and speed information of the carrier; Satellite navigation system, used to receive satellite signals and provide real-time position and speed information; A threshold setting module dynamically sets the satellite navigation position threshold and the satellite navigation speed threshold according to the characteristics of the error divergence of the inertial navigation system over time; The comparison and judgment module compares the inertial navigation position of a new frame with the satellite navigation position to determine whether the position information is spoofed, and compares the inertial navigation speed with the satellite navigation speed to determine whether the speed information is spoofed; The state management module manages the combined navigation state according to the result of the comparison and judgment module, including maintaining the combined navigation or exiting the combined navigation.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein the computer program implements the method steps of any one of claims 1 to 7 when executed by a processor.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method steps of any one of claims 1 to 7 are implemented.

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