Forwarding deception signal positive delay optimization method based on deception jamming delay model

Abstract

The present invention proposes a forwarding deception signal positive delay optimization method based on a deception interference delay model. The method is based on the principle that the smaller the delay at the time when the deception signal is added, the smaller the clock difference jump of the real signal. The delay is added gradually to effectively reduce the clock difference jump. The method first calculates the distance between the jammer, the receiver and the deception location, gives a calculation model for the forwarding deception interference delay, and calculates the artificial delay that needs to be added to each satellite based on this model. Then, the clock difference jump amplitude and threshold setting of the original signal are used to obtain a positive delay addition model, and the forwarding deception signal is obtained by delaying and remodulating the signal. Compared with traditional methods, this deception method can effectively reduce the clock difference jump caused by adding artificial delays. While ensuring the accuracy of the forwarding deception positioning results, the concealment of the deception interference is improved.

Description

Technical Field

[0001] The present invention relates to the field of GPS technology, and in particular to a forwarding deception signal positive delay optimization method based on a deception interference delay model. Background Art

[0002] The Global Positioning System (GPS) is a satellite system consisting of 24 satellites covering the entire world. It is the second generation satellite navigation system of the United States developed on the basis of the Transit satellite navigation system. In the military, GPS technology can provide accurate navigation and positioning information, helping the military to accurately determine the target location, plan the route of action and accurately locate on the battlefield. In the civilian field, the most obvious application is the in-vehicle navigation system, which can help drivers plan the best route, avoid traffic jams and guide them to the destination. In addition, GPS is also used in aviation navigation, ship navigation, agriculture, geological exploration, disaster relief, logistics and transportation, outdoor adventure and outdoor sports.

[0003] With the continuous extensive and in-depth application of GPS, the deception jamming technology related to GPS is also receiving continuous development and attention. In the military field, GPS deception jamming can be used to destroy the navigation system of enemy military units, causing them to lose accurate control of their geographical location. This interference can lead to misleading, confusion and delays, causing tactical disadvantages to the enemy. In the civilian field, with the rapid development of drones, their widespread and disorderly use seriously threatens social security, and these problems can be effectively controlled by using GPS deception jamming technology.

[0004] The key to traditional GPS forwarding deception jamming technology lies in signal delay control, which is achieved by adding artificial delay to the signal to deceiving the target receiver. However, this method of directly adding delay will cause obvious clock difference jumps when the deceiving signal invades. Existing receivers have a certain anti-deception capability, making traditional forwarding deception easy to detect and less concealed.

[0005] The existing technology comparison is as follows;

[0006] Comparative Patent 1: A capture method and receiver for anti-forwarding deception, authorization announcement date, 2020 / 3 / 17; authorization announcement date number: CN106814375B,

[0007] The invention discloses a capture method and receiver that are resistant to forwarding deception. The method determines whether forwarding deception interference exists by performing a two-dimensional code frequency search on each satellite signal. If forwarding deception interference exists, two tracking channels are opened to track the two signals respectively. The two tracking channels are bit synchronized to obtain the signal delays of the two signals. The signal delays of the two signals are compared, and the tracking channel of the signal with the larger signal delay is closed. The tracking channel of the signal with the smaller signal delay is opened again, and the frame synchronization telegram of the signal is solved, and the signal is positioned using the signal.

[0008] Although it also involves forwarding deceptive interference, the comparison technology mainly focuses on how to effectively detect and suppress forwarding deceptive interference; while the present application mainly focuses on how to optimize the forwarding deceptive interference process and use the forwarding deceptive interference model to further optimize the deceptive signal.

[0009] Comparative Patent 2: A forwarding drone navigation deception method, authorization announcement date, 2022 / 6 / 24; authorization announcement date number: CN114660623A,

[0010] The invention provides a forwarding UAV navigation deception method, which determines the coordinates of the forwarding device itself and the coordinates of the ith satellite; calculates the propagation delay of the navigation signal from the ith satellite to the forwarding device, the propagation delay of the navigation signal from the forwarding device to the target UAV, and the propagation delay of the ith satellite to the decoy coordinates; and then obtains the forwarding delay of the signal of the ith satellite; calculates the common delay to correct the forwarding delay, and delays the ith satellite signal according to the corrected forwarding delay, superimposes the delayed satellite signals to form a deception interference signal, radiates to the target UAV, and realizes forwarding navigation deception interference to the UAV.

[0011] Although it also involves improvements to forwarding deception interference, the main optimization method in this technology is to separately calculate the visible navigation satellites in the current sky, separate the forwarding delay of the purified signal, and correct the deception signal lag according to the relative position relationship between the target UAV and the forwarding device. At the same time, the deception position is updated in real time according to the target UAV position obtained by the detection equipment to form a dynamic deception interference trajectory, thereby reducing the probability of the deception signal being detected and identified; and the optimization method in this application is to intermittently add deception delays, which can significantly reduce the clock difference jump at the time of intrusion, while ensuring the accuracy of the forwarding deception positioning results, better achieve the deception effect, and improve the concealment of the deception interference. Summary of the invention

[0012] In order to solve the above technical problems, the present invention proposes a forwarding deception signal positive delay optimization method based on a deception interference delay model. This method can effectively reduce the clock difference jump, and better achieve the deception effect while ensuring the accuracy of the forwarding deception positioning results.

[0013] To achieve the above object, the technical solution adopted by the present invention is:

[0014] The forwarding deception signal positive delay optimization method based on the deception interference delay model is characterized by: the specific steps are as follows:

[0015] (1) Receive real satellite signals and determine the target receiver A coordinates (X a ,Y a ,Z a ), the coordinates of the deceptive jammer T (X t , Y t , Z t ) and the coordinates of the i-th positioning satellite

[0016] (2) Determine the coordinates of the location B to be deceived (X b , Y b , Z b );

[0017] (3) Calculate the actual distance S between the positioning satellite and the jammer i T, the actual distance S between the positioning satellite and the spoofed position i B, the actual distance TA between the jammer and the target receiver;

[0018] (4) obtaining a calculation model of the forwarding deception jamming delay according to the actual distance obtained in step (3);

[0019] (5) According to the calculation model of the forwarding deception interference delay obtained in step (4), the delay τ that needs to be added to the i-th satellite is calculated. i ;

[0020] (6) Obtaining the clock difference jump amplitude and threshold of the original signal;

[0021] (7) Obtaining a positive delay addition model based on the clock difference jump amplitude and threshold of the original signal obtained in step (6) and the delay amount calculated in step (5);

[0022] (8) Calculate the frequency N according to the positive delay incremental model obtained in step (7) m And the delay τ increased each time i ' ,k ;

[0023] (9) According to the delay amount and frequency obtained in step (8), add delay to each satellite intermittently, superimposing once every Δt, for a total of ΔtN m To complete the deception, generate navigation messages and C / A codes, and re-modulate them on the carrier to generate forwarding signals to achieve forwarding deception interference.

[0024] Further, step (4) specifically includes:

[0025] (4.1) The satellite signal positioning equation for the receiver to lock onto the target receiver is as follows:

[0026]

[0027] In the formula, ρ i (i=1,2,3,4) represents the pseudo-range between the user receiver and each satellite calculated by the user receiver based on the navigation message modulated in the real satellite signal, S i A(i=1,2,3,4) represents the actual distance between the target receiver and the satellite, t u Represents the clock difference between the satellite clock and the user receiver clock.

[0028] (4.2) According to step (4.1), when the target receiver locks the forwarding signal, the positioning equation is as follows:

[0029]

[0030] In the formula, S i T(i=1,2,3,4) represents the actual distance between the participating positioning satellite and the jammer, TA represents the actual distance between the jammer and the target receiver, t i (i=1, 2, 3, 4) represents the artificially added delay of each satellite signal.

[0031] (4.3) According to steps (4.1) and (4.2), in order to make the target receiver locate the wrong location to the deceptive location, the positioning equation is as follows:

[0032]

[0033] (4.4) According to step (4.3), the calculation model of the forwarding deception interference delay is as follows:

[0034]

[0035] Where, t i (i=1, 2, 3, 4) indicates the artificial delay that needs to be added for the i-th satellite.

[0036] Furthermore, the frequency N of adding delay in step (7) m The calculation formula is:

[0037]

[0038] Where N m Indicates the delay increase frequency threshold, τ min Indicates the minimum delay, dt maxIt represents the maximum amplitude of the local clock difference, and δl represents the threshold set for the clock difference detection jump.

[0039] Furthermore, the calculation formula for the delay amount τ that needs to be added to each satellite each time in step (8) is:

[0040]

[0041] In the formula, τ i ' ,k is the delay that each satellite needs to add each time, t is the local time, n k For the kth increase in delay, N m Indicates the delay increase frequency threshold.

[0042] Beneficial effects:

[0043] Compared with the prior art, the present invention has the following significant advantages: the present invention is based on a forwarding deception signal positive delay optimization method based on a deception interference delay model. The method first obtains the three-dimensional coordinates of the target receiver, the deception jammer and the deception position, and calculates the amount of artificial delay required to achieve deception interference by positioning the satellite and the jammer, the positioning satellite and the deception position, and the jammer and the target receiver. Before adding delay to the signal, a method of intermittently adding deception delay is used to calculate the frequency and amount of added delay. Compared with traditional methods, the present invention can significantly reduce the clock difference jump at the time of intrusion, while ensuring the accuracy of the forwarding deception positioning result, better achieve the deception effect, and improve the concealment of deception interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0046] This example provides a forwarding deception signal positive delay optimization method based on a deception interference delay model, such as Figure 1 As shown, including:

[0047] Step 1: Receive real satellite signals and determine the target receiver A coordinates (X a ,Y a ,Z a ), the coordinates of the deceptive jammer T (X t , Y t , Z t ) and the coordinates of the i-th positioning satellite

[0048] Step 2: Determine the coordinates of the location B to be deceived (Xb , Y b , Z b );

[0049] Step 3: Calculate the actual distance S between the positioning satellite and the jammer i T, the actual distance S between the positioning satellite and the spoofed position i B, the actual distance TA between the jammer and the target receiver;

[0050] Step 4: Obtain a calculation model of the forwarding deception jamming delay according to the obtained real distance;

[0051] This step specifically includes:

[0052] (4.1) The satellite signal positioning equation for the receiver to lock onto the target receiver is as follows:

[0053]

[0054] In the formula, ρ i (i=1,2,3,4) represents the pseudo-range between the user receiver and each satellite calculated by the user receiver based on the navigation message modulated in the real satellite signal, S i A(i=1,2,3,4) represents the actual distance between the target receiver and the satellite, t u Represents the clock difference between the satellite clock and the user receiver clock.

[0055] (4.2) According to step (4.1), when the target receiver locks the forwarding signal, the positioning equation is as follows:

[0056]

[0057] In the formula, S i T(i=1,2,3,4) represents the actual distance between the participating positioning satellite and the jammer, TA represents the actual distance between the jammer and the target receiver, t i (i=1, 2, 3, 4) represents the artificially added delay of each satellite signal.

[0058] (4.3) According to steps (4.1) and (4.2), in order to make the target receiver locate the wrong location to the deceptive location, the positioning equation is as follows:

[0059]

[0060] (4.4) According to step (4.3), the calculation model of the forwarding deception interference delay is as follows:

[0061]

[0062] In the formula, t i(i=1, 2, 3, 4) indicates the artificial delay that needs to be added for the i-th satellite.

[0063] Step 5: Calculate the delay τ that needs to be added to the i-th satellite according to the obtained calculation model of the forwarding deception interference delay: i ;

[0064] Step 6: Obtain the clock difference jump amplitude and threshold of the original signal;

[0065] Step 7: Obtain a positive delay addition model based on the clock difference jump amplitude and threshold of the original signal and the delay calculated in step (5);

[0066] The frequency of adding delay is N m The calculation formula is:

[0067]

[0068] Where N m Indicates the delay increase frequency threshold, τ min Indicates the minimum delay, dt max It represents the maximum amplitude of the local clock difference, and δl represents the threshold set for the clock difference detection jump.

[0069] For example, through analysis of collected data, the data of the clock difference of the local signal within the selected time period is within 1.2, reaching 92.61%. If the threshold is set to 10%, the delay increase frequency calculated by the above formula is 3000.

[0070] Step 8: Calculate the frequency N based on the obtained positive delay addition model m And the delay τ increased each time i ' ,k ;

[0071] Among them, the delay τ i ' ,k The calculation formula is:

[0072]

[0073] In the formula, τ i ' ,k is the delay that each satellite needs to add each time, t is the local time, n k For the kth increase in delay, N m Indicates the delay increase frequency threshold.

[0074] Step 9: According to the obtained delay amount and frequency, add delay to each satellite intermittently, superimpose once every Δt, a total of ΔtN mTo complete the deception, generate navigation messages and C / A codes, and re-modulate them on the carrier to generate forwarding signals to achieve forwarding deception interference.

[0075] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A forwarding deception signal positive delay optimization method based on a deception interference delay model, characterized by: The specific steps are as follows: (1) Receive real satellite signals and determine the target receiver A coordinates (X a ,Y a ,Z a ), the coordinates of the deceptive jammer T (X t , Y t , Z t ) and the coordinates of the i-th positioning satellite (2) Determine the coordinates of the location B to be deceived (X b , Y b , Z b ); (3) Calculate the actual distance between the positioning satellite and the jammer |S i T|, the real distance between the positioning satellite and the spoofed position |S i B|, the actual distance between the jammer and the target receiver |TA|; (4) obtaining a calculation model of the forwarding deception jamming delay according to the actual distance obtained in step (3); (5) According to the calculation model of the forwarding deception interference delay obtained in step (4), the delay τ that needs to be added to the i-th satellite is calculated. i ; (6) Obtaining the clock difference jump amplitude and threshold of the original signal; (7) Obtaining a positive delay addition model based on the clock difference jump amplitude and threshold of the original signal obtained in step (6) and the delay amount calculated in step (5); (8) Calculate the frequency N according to the positive delay incremental model obtained in step (7) m And the delay τ increased each time i ' ,k ; (9) According to the delay amount and frequency obtained in step (8), add delay to each satellite intermittently, superimposing once every Δt, for a total of ΔtN m To complete the deception, generate navigation messages and C / A codes, and remodulate them on the carrier to generate forwarding signals to achieve forwarding deception interference.

2. The forwarding deception signal positive delay optimization method based on the deception interference delay model according to claim 1 is characterized in that: Step (4) specifically includes: (4.1) The satellite signal positioning equation for the receiver to lock onto the target receiver is as follows: In the formula, ρ i (i=1,2,3,4) represents the pseudo-range between the user receiver and each satellite calculated by the user receiver based on the navigation message modulated in the real satellite signal, |S i A|, i = 1, 2, 3, 4 represents the actual distance between the target receiver and the satellite, t u Represents the clock difference between the satellite clock and the user receiver clock; (4.2) According to step (4.1), when the target receiver locks the forwarding signal, the positioning equation is as follows: In the formula, |S i T|(i=1,2,3,4) represents the actual distance between the participating positioning satellite and the jammer, |TA| represents the actual distance between the jammer and the target receiver, t i , i=1,2,3,4 represents the artificially increased delay of each satellite signal; (4.3) According to steps (4.1) and (4.2), in order to make the target receiver locate the wrong location to the deceptive location, the positioning equation is as follows: (4.4) According to step (4.3), the calculation model of the forwarding deception interference delay is as follows: In the formula, t i , i=1,2,3,4 represents the artificial delay that needs to be added for the i-th satellite.

3. The forwarding deception signal positive delay optimization method based on the deception interference delay model according to claim 2 is characterized in that: The frequency N of adding delay in step (7) m The calculation formula is: Where N m Indicates the delay increase frequency threshold, τ min Indicates the minimum delay, dt max It represents the maximum amplitude of the local clock difference, and δl represents the threshold set for the clock difference detection jump.

4. The forwarding deception signal positive delay optimization method based on the deception interference delay model according to claim 1 is characterized in that: The calculation formula for the delay τ that needs to be added to each satellite each time in step (8) is: In the formula, τ i ' ,k is the delay that each satellite needs to add each time, t is the local time, n k For the kth increase in delay, N m Indicates the delay increase frequency threshold.

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