Navigation anti-interference method based on multi-inertial navigation information comprehensive decision

Abstract

The invention provides a navigation anti-interference method based on multi-inertial navigation information comprehensive decision, which comprises the following steps of: based on more than three sets of configured high-precision inertial navigation systems, firstly obtaining position errors of two sets of gyro inertial navigation systems, then obtaining position error increments of the two sets of gyro inertial navigation systems and Beidou, and finally obtaining the position error increments of the two sets of gyro inertial navigation systems and the Beidou; comparing the two position error increments with the position errors of the two sets of gyro inertial navigation systems, and judging whether the position information of the Beidou is reliable or not; if the judgment result cannot be obtained, further judging whether interference occurs or not according to the relationship between the third set of gyro inertial navigation system and the position error increment of the Beidou, so that the method can be used for detecting interference information possibly existing in the Beidou navigation system, and the system can take isolation measures in time conveniently; interference information is prevented from entering the system in a feedback correction mode to influence the precision of the navigation system.

Description

Technical Field

[0001] The present invention belongs to the technical field of navigation anti-interference, and in particular relates to a navigation anti-interference method based on comprehensive decision-making of multiple inertial navigation information. Background Art

[0002] The navigation system used by underwater vehicles is composed of multiple sets of high-precision inertial navigation systems and global positioning navigation systems. When sailing under the water, underwater vehicles cannot receive satellite signals and can only rely on inertial navigation. However, inertial navigation has the characteristic of gradually accumulating errors over time. Therefore, after a period of underwater navigation, underwater vehicles need to surface to receive Beidou satellite navigation signals to calibrate the inertial navigation system of underwater vehicles. However, due to interference, the navigation system may not be able to receive completely reliable Beidou satellite signals.

[0003] Interference with satellite signals is mainly divided into suppression interference and deception interference. Suppression interference can be effectively suppressed at the receiver level through anti-interference technologies such as array antennas. Deception interference is divided into forwarding deception interference and generative deception interference. Since these malicious deception attack interferences are usually purposeful and may present a variety of error characteristics, including the time of the deception attack, the amplitude of the deception, and the change of the deception distance over time, these factors increase the complexity and difficulty of effectively detecting deception signals.

[0004] With the development of satellite navigation technology, especially the increasing coverage of my country's Beidou satellite navigation system, intentional or unintentional deception interference will affect the application security of the Beidou satellite navigation system, especially intentional deception interference, which will directly cause the positioning terminal to generate "wrong" location information and pollute the entire navigation system. The existence of deception interference makes it impossible to guarantee the effectiveness of the positioning information of the Beidou satellite navigation system. If the receiver misses the deceptive interference, the interfered Beidou position information will be introduced into the inertial navigation system through the information fusion module, resulting in a decrease in the accuracy of the navigation information or even unavailability, threatening the navigation performance of underwater vehicles. Starting from the actual needs of the navigation system for underwater vehicles, the present invention studies how to use the inertial navigation system to detect deceptive interference signals from a system level.

[0005] Current research focuses on the following aspects: receiver tracking loop, inertial assistance, antenna array, pseudorange / carrier phase difference, hypothesis testing and correlation, etc. The receiver tracking loop method requires redesigning the existing receiver. In order to reduce the complexity of the algorithm, the present invention uses fault detection based on inertial navigation information to assist Beidou navigation in navigation interference detection. Summary of the invention

[0006] In view of this, an object of the present invention is to provide a navigation anti-interference method based on comprehensive decision-making of multiple inertial navigation information.

[0007] A navigation anti-interference method based on comprehensive decision-making of multiple inertial navigation information, comprising:

[0008] For the three configured inertial navigation systems, two of them are marked as SINS-1 and SINS-2, and the third one is marked as SINS-3;

[0009] Calculate the position error within the unit interval of the first inertial navigation system SINS-1, that is, the longitude and latitude errors, expressed as:

[0010]

[0011] in, and They represent the longitude of the first epoch t0 and the second epoch t1 of the first inertial navigation system in the unit interval, and They represent the latitude of the first inertial navigation system at the first epoch t0 and the second epoch t1 respectively;

[0012] The position errors of the three inertial navigation systems are: and The position error of Beidou is:

[0013] Compare the position errors of the first inertial navigation system SINS-1, the second inertial navigation system SINS-2 and Beidou in pairs:

[0014] The position error increment between the first inertial navigation system and the second inertial navigation system within the unit interval is:

[0015]

[0016] The position error increment between the first inertial navigation system SINS-1 and Beidou in the unit interval is:

[0017]

[0018] The position error increment between the second inertial navigation system SINS-2 and Beidou in the unit interval is:

[0019]

[0020] (1) If both of the following conditions are met: and Among them, th represents the set threshold value, which means that the position error of Beidou in the unit interval is inconsistent with the two inertial navigation systems, and the Beidou signal is interfered;

[0021] (2) If only one of the two conditions is met, namely: or Then calculate the position error between the third inertial navigation system SINS-3 and Beidou in the unit interval, and continue to judge:

[0022]

[0023] 1) If the conditions are met This means that Beidou navigation is interfered in the unit interval;

[0024] 2) If the conditions are not met: This means that the position error within the Beidou unit interval is consistent with the first inertial navigation system SINS-1 and the second inertial navigation system SINS-2, and the Beidou signal has not been deceived or interfered with.

[0025] Preferably, when it is determined that the Beidou signal is interfered, the Beidou output signal is not used to correct the inertial navigation system position, and then the detection of the next epoch is continued.

[0026] Preferably, when it is determined that the Beidou signal is not deceptively interfered with, the Beidou output information feedback is used to correct the position of the inertial navigation system.

[0027] The present invention has the following beneficial effects:

[0028] The invention provides a navigation anti-interference method based on comprehensive decision-making of multiple inertial navigation information. Based on more than three configured high-precision inertial navigation systems, the position errors of two gyro inertial navigation systems are firstly obtained, and then the position error increments of the two gyro inertial navigation systems and Beidou are obtained. The two position error increments are compared with the position errors of the two gyro inertial navigation systems to judge whether the position information of Beidou is reliable; if the judgment result cannot be obtained, the relationship between the position error increments of the third gyro inertial navigation system and Beidou is further used to judge whether interference occurs. The method can detect interference information that may exist in the Beidou navigation system, so that the system can take isolation measures in time to prevent the interference information from entering the system through feedback correction and affecting the accuracy of the navigation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a structural diagram of the multi-redundant inertial navigation voting method for judging Beidou deception and interference methods. DETAILED DESCRIPTION

[0030] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0031] Step 1: Perform inertial navigation solution to obtain the position, velocity and attitude information output by the three inertial navigation systems.

[0032] Step 2: Determine whether there is inertial navigation position information at a historical moment in the system. If so, continue the operation; otherwise, return to step 1.

[0033] Step 3: If the system has inertial navigation position information at historical moments, calculate the position difference between the current moment and the historical moment.

[0034] Step 4: Based on the position difference between the current and historical moments of multiple inertial navigation systems, a comprehensive decision-making method is used to determine whether there is an interference signal in the Beidou signal. The specific principle is as follows: Due to its special working conditions and important role, underwater vehicles have important requirements for the reliability of their navigation systems. Therefore, they are usually equipped with more than three high-precision inertial navigation systems. Due to the high accuracy of the inertial system, although the position error will gradually accumulate over time, its short-term accuracy is high. Therefore, the redundant information voting of multiple inertial navigation systems can be used to determine whether the received Beidou information is deceived.

[0035] When the Beidou signal can be received, the first epoch is recorded as t0. After a period of time, the position error of each fixed time period can be obtained. The three high-precision inertial navigation systems can also obtain the position error of each fixed time period. Two of them can be marked as SINS-1 and SINS-2, and the third gyro is marked as SINS-3. Since it is usually difficult for the deceptive attacker to ensure the consistency of the attack distance, the position error before and after may be inconsistent. In this way, the position error of the three inertial navigation systems can be used to detect whether the Beidou position information is reliable.

[0036] Taking the first set of gyro SINS-1 as an example, the position error within the unit interval, that is, the longitude and latitude error can be expressed as:

[0037]

[0038] in, and denote the longitude of the first gyro inertial navigation system at the first epoch t0 and the second epoch t1, respectively. and denote the latitude of the first gyro inertial navigation system at the first epoch t0 and the second epoch t1 respectively;

[0039] Therefore, the position errors of the three gyro inertial navigation systems can be expressed as:

[0040] and The position error of Beidou is expressed as:

[0041] The position errors of the first gyro inertial navigation system SINS-1, the second gyro inertial navigation system SINS-2 and Beidou are compared pairwise:

[0042] The position error increment between the first gyro inertial navigation system and the second gyro inertial navigation system in the interval is:

[0043]

[0044] The position error increment between the first gyro inertial navigation system SINS-1 and Beidou in the interval is:

[0045]

[0046] The position error increment between the second gyro inertial navigation system SINS-2 and Beidou in the interval is:

[0047]

[0048] (1) If both of the following conditions are met: and Among them, th represents the set threshold value, which means that the position error within the Beidou interval is inconsistent with the two gyro inertial navigation systems, and Beidou has a high probability of being deceived;

[0049] (2) If only one of the two conditions is met: or Then the position error between the third gyro inertial navigation system SINS-3 and Beidou in the interval is introduced to continue the judgment:

[0050]

[0051] 1) If the conditions are met This means that Beidou navigation has a high probability of being deceived in the interval;

[0052] 2) If the conditions are not met: This means that the position error within the Beidou range is consistent with that of SINS-1 and SINS-2, and the Beidou signal has not been spoofed or interfered with.

[0053] Step 5: Use Beidou signals to correct inertial navigation information

[0054] When it is determined that the Beidou signal is not deceptively interfered with, the Beidou output information feedback is used to correct the position of the inertial navigation system;

[0055] When it is determined that there is a high probability that Beidou has been deceived, the Beidou output signal is not used to correct the inertial navigation system position, and the detection of the next epoch is continued.

[0056] Example:

[0057] In this embodiment, the indicators of the deception interference identification method are defined as follows:

[0058] In each group of experiments, the total number of recognitions is N (when there is sudden interference in the system, each detection is defined as one recognition; when there is slow-changing interference in the system, the detection result of the system within 10s is defined as one recognition; when the system cannot detect interference within 10s, it is defined that one detection has occurred and one missed detection), the number of times without interference is N1, the number of times with interference is N2, the number of times without interference but interference is recognized is F, and the number of times with interference but interference is not recognized within the specified time is M.

[0059] The false alarm rate and missed alarm rate can be calculated based on the data obtained in the algorithm. The false alarm rate is FP = F / N1, the missed alarm rate is MP = M / N2, and the accuracy rate is RP = (N°FM) / N.

[0060] Under different noise seed conditions, 10 simulated trajectories were generated, each with a duration of 120 seconds, a strapdown inertial navigation sampling period of 0.01 seconds, and a GNSS sampling period of 1 second; the pitch-roll-azimuth misalignment angle was set to [0.5; -0.5; 0.2], in degrees. The parameters of the three sets of inertial navigation tests used in the experiment are shown in the table: Deception detection was performed on the basis of trajectories 1-10, and experiment n was performed under the condition of experimental parameters n (n = 1, 2, 3, .., 10). The parameters of deception interference are shown in Table 1, and the detection results are shown in Table 2.

[0061] Table 1 Inertial navigation initial information and satellite navigation slowly changing interference parameter setting table

[0062]

[0063]

[0064] The interference detection results are as follows:

[0065] Table 2 Statistics of interference identification results

[0066]

[0067]

[0068] From the statistical information in the above table, we know that the false detection rate of the algorithm can be maintained above 90%, no missed detection occurs, and the detection time under various conditions is less than 1s, indicating that the algorithm has excellent performance, and has good performance in false detection rate, missed detection rate and detection speed. The navigation anti-interference algorithm proposed in the present invention can effectively detect the interference in the system, and has excellent performance in both detection speed and detection accuracy.

[0069] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A navigation anti-interference method based on comprehensive decision-making of multiple inertial navigation information, characterized in that: include: For the three configured inertial navigation systems, two of them are marked as SINS-1 and SINS-2, and the third one is marked as SINS-3; Calculate the position error within the unit interval of the first inertial navigation system SINS-1, that is, the longitude and latitude errors, expressed as: in, and They represent the longitude of the first epoch t0 and the second epoch t1 of the first inertial navigation system in the unit interval, and They represent the latitude of the first inertial navigation system at the first epoch t0 and the second epoch t1 respectively; The position errors of the three inertial navigation systems are: and The position error of Beidou is: Compare the position errors of the first inertial navigation system SINS-1, the second inertial navigation system SINS-2 and Beidou in pairs: The position error increment between the first inertial navigation system and the second inertial navigation system within the unit interval is: The position error increment between the first inertial navigation system SINS-1 and Beidou in the unit interval is: The position error increment between the second inertial navigation system SINS-2 and Beidou in the unit interval is: (1) If both of the following conditions are met: and Among them, th represents the set threshold value, which means that the position error of Beidou in the unit interval is inconsistent with the two inertial navigation systems, and the Beidou signal is interfered; (2) If only one of the two conditions is met, namely: or Then calculate the position error between the third inertial navigation system SINS-3 and Beidou in the unit interval, and continue to judge: 1) If the conditions are met This means that Beidou navigation is interfered in the unit interval; 2) If the conditions are not met: This means that the position error within the Beidou unit interval is consistent with the first inertial navigation system SINS-1 and the second inertial navigation system SINS-2, and the Beidou signal has not been deceived or interfered with.

2. A navigation anti-interference method based on comprehensive decision-making of multiple inertial navigation information as claimed in claim 1, characterized in that: When it is determined that the Beidou signal is interfered, the Beidou output signal is not used to correct the inertial navigation system position, and then the detection of the next epoch is continued.

3. The navigation anti-interference method based on multi-inertial navigation information comprehensive decision-making as claimed in claim 2 is characterized in that: When it is determined that the Beidou signal has not been deceitfully interfered with, the Beidou output information feedback is used to correct the position of the inertial navigation system.

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