An asynchronous traction-based deception threshold testing method for critical infrastructure

Abstract

The present application relates to an asynchronous traction type spoofing threshold test method for key infrastructure. The method includes: implementing asynchronous traction type spoofing on a target receiver based on configured spoofing signals, traversing a set of simulation parameter configurations of the target receiver, configuring the target receiver according to the current simulation parameters of the target receiver, inputting a mixed signal into the target receiver, determining spoofing success based on the processing result of the target receiver for the mixed signal to obtain corresponding determination results, counting each determination result to obtain the spoofing success rate under each simulation parameter configuration of the target receiver, obtaining a spoofing traction speed reference threshold according to the spoofing traction speed corresponding to the preset spoofing success rate, and guiding the key infrastructure to perform security detection according to the receiver parameters corresponding to the key infrastructure, the set of simulation parameter configurations of the target receiver, and the spoofing traction speed reference threshold. Using this method can improve the reliability of security detection and the anti-asynchronous spoofing ability of important infrastructure.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to an asynchronous traction-type deception threshold testing method for key infrastructure. Background Art

[0002] Currently, the world's four major satellite navigation systems can provide high-precision, all-weather positioning, navigation, and timing services to users around the world in real time, and have important applications and significance in all aspects of production and life. While the application of the Global Navigation Satellite System (GNSS) is ubiquitous and rapidly developing, GNSS spoofing technology is also developing at the same rapid pace, making the security of GNSS an international issue that needs to be addressed urgently. In particular, research on spoofing security detection for major infrastructure is relatively scarce. The navigation receivers of such facilities generally perform important functions such as timing and positioning, but the civilian receivers they use have certain defects in resisting generative spoofing. In the future, when key infrastructure faces various spoofing interference, how to conduct industry spoofing security detection will be an important issue.

[0003] GNSS spoofing is a form of malicious, man-made interference that poses a greater threat than suppression jamming. Suppression jamming primarily utilizes high-power jamming signals to force the target receiver to lose lock, thereby losing navigation and positioning capabilities. Spoofing, on the other hand, is more subtle, forcing the target receiver to track a false spoofing signal, resulting in erroneous velocity, positioning, and time information. Generative spoofing can be categorized into asynchronous and synchronous generative spoofing, depending on whether the generated spoofing signal is synchronized with the actual satellite signal.

[0004] For synchronous generative deception, it is necessary to know the information of the real signal in advance, and then seize the tracking loop during the transmission of the deception signal by virtue of the high-power advantage to achieve deception. However, in actual application scenarios, the spoofing device usually cannot obtain the precise parameters of the target receiver, and the relevant parameters of the generated spoofing signal usually deviate from the real signal parameters, which may cause the receiver tracking loop to lose lock. Asynchronous deception can synchronize and pull the spoofing signal and the real signal without knowing the precise parameters of the real signal and without the receiver losing lock. Existing research is based on initial code phase alignment or within two chip intervals, and realizes position offset by setting the pseudo-code delay. Existing research mainly focuses on the exploration of this deception pattern and the analysis of the deception mechanism. The pulling speed of asynchronous deception is the key factor for its success. Traditional methods deceive the receiver by setting a fixed pseudo-code offset speed. However, these methods are all studies for the spoofing party and cannot provide reliable security detection guidance for the deceived party under the asynchronous deception pattern. Therefore, how to provide a reference for the security detection of key infrastructures facing asynchronous deception has become an urgent problem to be solved. Summary of the Invention

[0005] Based on this, in view of the above technical problems, it is necessary to provide an asynchronous pulling deception threshold test method for key infrastructures.

[0006] An asynchronous pulling deception threshold test method for key infrastructures, the method includes:

[0007] Configure a spoofing signal according to pre-set spoofing signal simulation parameters, and obtain a mixed signal according to the spoofing signal and the navigation satellite signal; the spoofing signal simulation parameters include a starting offset point, a target offset point, a pseudo-code offset speed, a signal power gain, and a spoofing entry time; the spoofing signal is used to implement asynchronous pulling deception;

[0008] Traverse a pre-set set of target receiver simulation parameter configurations, configure a target receiver according to the current target receiver simulation parameters, input the mixed signal into the target receiver, and determine whether the spoofing is successful according to the processing result of the target receiver for the mixed signal to obtain a corresponding determination result; the target receiver simulation parameters include the code loop order, the loop bandwidth, and the damping coefficient;

[0009] Count each determination result to obtain the spoofing success rate under each target receiver simulation parameter configuration, and obtain a spoofing pulling speed reference threshold according to the spoofing pulling speed corresponding to the pre-set spoofing success rate;

[0010] Guide the security detection of key infrastructures according to the receiver parameters corresponding to the key infrastructures, the set of target receiver simulation parameter configurations, and the spoofing pulling speed reference threshold.

[0011] In one embodiment, it further includes: finding the matching parameters of the receiver parameters corresponding to the key infrastructure in the target receiver simulation parameter set, obtaining the critical value at which the receiver of the key infrastructure is successfully spoofed when encountering spoofing according to the spoofing traction speed reference threshold corresponding to the matching parameters; assisting in optimizing the receiver parameters corresponding to the key infrastructure according to the relationship between the matching parameters and the spoofing traction speed reference threshold.

[0012] In one embodiment, it further includes: increasing the spoofing traction speed threshold by increasing the receiver loop bandwidth; when the damping coefficient in the matching parameters shows underdamping, increasing the receiver damping coefficient to increase the spoofing traction speed threshold, and when the damping coefficient shows overdamping, decreasing the receiver damping coefficient to increase the spoofing traction speed threshold; and increasing the spoofing traction speed threshold by increasing the receiver loop order.

[0013] In one embodiment, it further includes: obtaining the correlation peak jump variable of each jump point according to the output result of the tracking code loop of the target receiver. If the correlation peak jump variable is greater than the jump threshold, perform stability detection on the i-th jump point after the jump point. If the stability detection is passed, it is determined that the asynchronous spoofing is successful; if the stability detection is not passed, it is determined that the asynchronous spoofing fails.

[0014] In one embodiment, it further includes: setting the time when the spoofing signal starts to appear in the mixed signal as the spoofing entry time of the spoofing signal; determining the deviation range according to the prior position information of the target receiver, and setting the starting pull-off point of the spoofing signal according to the deviation range; setting the pseudo-code pull-off speed of the spoofing signal according to the pseudo-code phase difference, the spoofing signal and the code phase of the navigation satellite signal; setting the target pull-off point of the spoofing signal according to the actual requirement; setting the signal power gain of the spoofing signal according to the power amplitudes of the spoofing signal and the navigation satellite signal; configuring the spoofing signal according to the starting pull-off point, the target pull-off point, the pseudo-code pull-off speed, the spoofing entry time and the signal power gain.

[0015] In one embodiment, it further includes: the target receiver simulation parameter set includes a parameter configuration sequence under the code tracking loop structure corresponding to each code loop order; the parameter configuration sequence includes a pair of receiver parameters composed of a plurality of loop bandwidths and damping coefficients; the code loop orders include a first-order code tracking loop, a second-order code tracking loop and a third-order code tracking loop.

[0016] In one embodiment, it further includes: traversing the target receiver simulation parameter set, and configuring the target receiver according to the current target receiver simulation parameters, including: traversing the parameter configuration sequence under the code tracking loop structure corresponding to each code loop order, and for the current parameter configuration sequence, traversing each pair of receiver parameters, and performing target receiver simulation configuration according to the current pair of receiver parameters.

[0017] An asynchronous traction type spoofing threshold test device for critical infrastructure, the device comprising:

[0018] A signal simulation module, configured to configure a spoofing signal according to pre-set spoofing signal simulation parameters, and obtain a mixed signal according to the spoofing signal and a navigation satellite signal; the spoofing signal simulation parameters include a starting offset point, a target offset point, a pseudo-code offset speed, a signal power gain, and a spoofing entry time; the spoofing signal is used to implement asynchronous traction type spoofing;

[0019] A receiver simulation module, configured to traverse a pre-set set of target receiver simulation parameter configurations, configure a target receiver according to the current target receiver simulation parameters, input the mixed signal into the target receiver, and determine spoofing success according to the processing result of the target receiver on the mixed signal, to obtain a corresponding determination result; the target receiver simulation parameters include a code loop order, a loop bandwidth, and a damping coefficient;

[0020] A threshold acquisition module, configured to count each determination result to obtain a spoofing success rate under each target receiver simulation parameter configuration, and obtain a spoofing traction speed reference threshold according to the spoofing traction speed corresponding to a pre-set spoofing success rate;

[0021] A security detection module, configured to guide the critical infrastructure to perform security detection according to the receiver parameters corresponding to the critical infrastructure, the set of target receiver simulation parameter configurations, and the spoofing traction speed reference threshold.

[0022] A computer device, comprising a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0023] Configure a spoofing signal according to pre-set spoofing signal simulation parameters, and obtain a mixed signal according to the spoofing signal and a navigation satellite signal; the spoofing signal simulation parameters include a starting offset point, a target offset point, a pseudo-code offset speed, a signal power gain, and a spoofing entry time; the spoofing signal is used to implement asynchronous traction type spoofing;

[0024] Traverse a pre-set set of target receiver simulation parameter configurations, configure a target receiver according to the current target receiver simulation parameters, input the mixed signal into the target receiver, and determine spoofing success according to the processing result of the target receiver on the mixed signal, to obtain a corresponding determination result; the target receiver simulation parameters include a code loop order, a loop bandwidth, and a damping coefficient;

[0025] Count each determination result to obtain a spoofing success rate under each target receiver simulation parameter configuration, and obtain a spoofing traction speed reference threshold according to the spoofing traction speed corresponding to a pre-set spoofing success rate;

[0026] Guide the security detection of key infrastructure according to the receiver parameters corresponding to the key infrastructure, the target receiver simulation parameter configuration set, and the spoofing traction speed reference threshold.

[0027] A computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0028] Configure a spoofing signal according to pre-set spoofing signal simulation parameters, and obtain a mixed signal according to the spoofing signal and the navigation satellite signal; the spoofing signal simulation parameters include a starting offset point, a target offset point, a pseudo-code offset speed, a signal power gain, and a spoofing entry time; the spoofing signal is used to implement asynchronous traction spoofing;

[0029] Traverse the pre-set target receiver simulation parameter configuration set, configure the target receiver according to the current target receiver simulation parameters, input the mixed signal into the target receiver, determine spoofing success according to the processing result of the target receiver on the mixed signal, and obtain the corresponding determination result; the target receiver simulation parameters include a code loop order, a loop bandwidth, and a damping coefficient;

[0030] Statistically obtain the spoofing success rate under each target receiver simulation parameter configuration for each determination result, and obtain a spoofing traction speed reference threshold according to the spoofing traction speed corresponding to the pre-set spoofing success rate;

[0031] Guide the security detection of key infrastructure according to the receiver parameters corresponding to the key infrastructure, the target receiver simulation parameter configuration set, and the spoofing traction speed reference threshold.

[0032] The above asynchronous traction spoofing threshold test method for key infrastructure configures a spoofing signal according to pre-set spoofing signal simulation parameters, obtains a mixed signal according to the spoofing signal and the navigation satellite signal, implements asynchronous traction spoofing on the target receiver based on the spoofing signal, traverses the pre-set target receiver simulation parameter configuration set, configures the target receiver according to the current target receiver simulation parameters, inputs the mixed signal into the target receiver, determines spoofing success according to the processing result of the target receiver on the mixed signal, obtains the corresponding determination result, statistically obtains the spoofing success rate under each target receiver simulation parameter configuration for each determination result, obtains a spoofing traction speed reference threshold according to the spoofing traction speed corresponding to the pre-set spoofing success rate, and guides the security detection of key infrastructure according to the receiver parameters corresponding to the key infrastructure, the target receiver simulation parameter configuration set, and the spoofing traction speed reference threshold. Embodiments of the present invention can improve the reliability of security detection and enhance the anti-asynchronous spoofing ability of important infrastructure. Description of the Drawings

[0033] Figure 1 Schematic flow diagram of an asynchronous traction deception threshold test method for critical infrastructure in an embodiment

[0034] Figure 2 Schematic diagram of the working principle of DLL in an embodiment

[0035] Figure 3 Basic principle block diagram of a loop filter in an embodiment

[0036] Figure 4 Schematic flow diagram of a simulation experiment in an embodiment

[0037] Figure 5 Schematic flow diagram of deception detection in an embodiment

[0038] Figure 6 Schematic diagram of deception pulling deviation results under a multi-loop structure in an embodiment

[0039] Figure 7 Schematic diagram of deception pulling deviation speed under different power gains in an embodiment

[0040] Figure 8 Structure block diagram of an asynchronous traction deception threshold test device for critical infrastructure in an embodiment

[0041] Figure 9 Internal structure diagram of a computer device in an embodiment Specific implementation manners

[0042] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0043] Regarding the navigation deception of critical infrastructure, the deception countermeasure scenario is a target receiver with imperceptible deception and prior position information error. Due to the insufficient prior position information of the target receiver, when using synchronous generated deception, it is necessary to first align with the code phase of the real navigation signal. This makes it impossible for synchronous deception to achieve imperceptible deception of a target receiver that is stably receiving navigation signals. Therefore, synchronous generated deception is not applicable to a receiver target with prior position information error. Asynchronous generated deception does not need to be synchronized with the navigation signal. It only needs to know the approximate position information of the target receiver and can imperceptibly cut in and control the target receiver that is stably receiving navigation signals by setting different deception traction speeds.

[0044] Since only the approximate position information of the target receiver can be obtained and the exact position cannot be acquired, this will introduce an initial position deviation of the target receiver. Assuming that the pseudo-code phase error is equal to the prior position information error, the spoofing party needs to first make up for this deviation so that the spoofing signal can be synchronized and aligned with the real navigation signal, and it can be ensured that alignment can be achieved within the range of both forward synchronization and reverse synchronization, and then offset to the target spoofing point. From the above analysis, it can be seen that the speed of the pulling speed in this process is the key parameter determining the success or failure of spoofing.

[0045] Here, it is assumed that the Δτ1 code phase time delay error is the prior position information error, and the error between the code phase of the spoofing start point set by the spoofing source and the code phase of the real signal is Δτ2, and Δτ2 is greater than Δτ1, that is, the initial offset range is greater than the prior position information error. According to the principle described above, this can ensure that alignment with the navigation signal can be achieved whether it is forward synchronization or reverse synchronization, and then offset the Δτ3 code phase time delay to the target spoofing point. It can be analyzed that the key to this process is the spoofing offset speed v s exploration:

[0046] v s *t1 + v s *t2 = Δτ2 + Δτ3 (1)

[0047] In the formula, t1 represents the alignment time of the spoofing signal and the navigation signal, and t2 represents the time for the spoofing signal to offset from the synchronization position to the target spoofing point.

[0048] According to the scenario assumption of asynchronous spoofing countermeasure, the synchronization and offset of the navigation signal are crucial in practical applications. Especially when the prior position information of the target receiver is insufficient, it is particularly necessary to study this process. The above scenario experimental analysis shows that the asynchronous spoofing offset process is of great significance for achieving an effective spoofing attack. Therefore, it is very valuable to further study its specific steps and technical details. The implementation process of asynchronous spoofing interference is mainly divided into three stages: First, the spoofing signal approaches the real signal with high power. Second, the two signals reach synchronization and align the autocorrelation function (ACF). Finally, the tracking point is completely controlled by the receiver with power advantage.

[0049] 1) Approaching stage: Since the exact code phase of the spoofing signal is unknown, the spoofing signal must maintain a power higher than that of the real signal and adjust its code rate at the same time so that its code phase approaches the code phase of the real signal, in order to ensure that the receiver tracking loop can be controlled with power advantage during the synchronization stage.

[0050] 2) Synchronization stage: The code phase and carrier frequency of the spoofing signal are synchronized with the code phase and carrier frequency of the real signal, and the autocorrelation peaks of the two are aligned.

[0051] 3) Pulling stage: In this stage, the spoofing signal continuously pulls the loop tracking point with power advantage until it is finally completely transferred to the target spoofing position. During the process of pulling off, the magnitude of the pulling speed determines the key factor for the success of the entire spoofing strategy.

[0052] In one embodiment, as Figure 1 shown, an asynchronous pulling spoofing threshold testing method for key infrastructure is provided, including the following steps:

[0053] Step 102, configure the spoofing signal according to the pre-set spoofing signal simulation parameters, and obtain a mixed signal based on the spoofing signal and the navigation satellite signal.

[0054] The spoofing signal simulation parameters include the starting pulling point, the target pulling point, the pseudo-code pulling speed, the signal power gain, and the spoofing entry time; the spoofing signal is used to implement asynchronous pulling spoofing.

[0055] Step 104, traverse the pre-set target receiver simulation parameter configuration set, configure the target receiver according to the current target receiver simulation parameters, input the mixed signal into the target receiver, and determine the spoofing success based on the processing result of the target receiver for the mixed signal to obtain the corresponding determination result.

[0056] The target receiver simulation parameters include the code loop order, the loop bandwidth, and the damping coefficient.

[0057] Step 106, count each determination result to obtain the spoofing success rate under each target receiver simulation parameter configuration, and obtain the spoofing pulling speed reference threshold according to the spoofing pulling speed corresponding to the pre-set spoofing success rate.

[0058] The spoofing success rate refers to the proportion of the number of successful spoofing attacks to the total number of attempts within a certain period of time or a certain number of spoofing attempts. The pre-set spoofing success rate can be set according to the actual requirements of security detection, which refers to the probability that the expected spoofing attack can succeed during security detection.

[0059] The spoofing pulling speed refers to the change speed of the pseudo-code rate of the spoofing signal. If the pseudo-code rate of the spoofing signal changes too fast or too much, resulting in too fast or too large a change in the pseudo-code phase difference between the spoofing signal and the real navigation signal, it may cause the receiver to lose lock, resulting in spoofing failure.

[0060] The spoofing pulling speed corresponding to the pre-set spoofing success rate refers to the spoofing pulling speed observed in the simulation test when the spoofing success rate reaches the pre-set value.

[0061] The spoofing pull-in speed reference threshold refers to the maximum spoofing pull-in speed that a target receiver can tolerate under a certain spoofing success rate. A spoofing pull-in speed exceeding this threshold will be considered a potential spoofing attack.

[0062] Step 108: Guide the security detection of critical infrastructure according to the receiver parameters corresponding to the critical infrastructure, the target receiver simulation parameter set, and the spoofing pull-in speed reference threshold.

[0063] Critical infrastructure refers to those systems and assets whose destruction or failure will have a serious impact on economic stability, public health, and safety. For example, critical infrastructure can be the time synchronization receivers in the power and financial industries.

[0064] In the above asynchronous pull-in spoofing threshold test method for critical infrastructure, the pull-in speed threshold of asynchronous spoofing is analyzed through simulation to provide a reference for future spoofing security detection of critical infrastructure. First, conduct a scenario experiment on the spoofing countermeasure scenario and establish a basic mathematical model; second, establish an asynchronous spoofing pull-in speed analysis model to analyze the impact of spoofing signals on the receiver loop. Based on the asynchronous spoofing pull-in speed analysis model, simulate the typical code loop structure of the receiver to obtain the pull-in speed threshold of asynchronous spoofing under different code loop structures. According to the influence rules of the obtained code loop bandwidth, damping coefficient, and loop order parameters on the spoofing pull-in speed threshold, assist in the security detection of the receivers of important infrastructure. The embodiments of the present invention can improve the reliability of security detection and enhance the anti-asynchronous spoofing ability of important infrastructure.

[0065] In one embodiment, configuring the spoofing signal according to the pre-set spoofing signal simulation parameters includes: setting the moment when the spoofing signal starts to appear in the mixed signal as the spoofing entry time of the spoofing signal; determining the deviation range according to the prior position information of the target receiver, and setting the starting offset point of the spoofing signal according to the deviation range; setting the pseudo-code offset speed of the spoofing signal according to the pseudo-code phase difference, the code phase of the spoofing signal, and the navigation satellite signal; setting the target offset point of the spoofing signal according to actual requirements; setting the signal power gain of the spoofing signal according to the power amplitudes of the spoofing signal and the navigation satellite signal; and configuring the spoofing signal according to the starting offset point, the target offset point, the pseudo-code offset speed, the spoofing entry time, and the signal power gain.

[0066] In this embodiment, the signal structure of the pull-in spoofing signal is the same as that of the navigation satellite signal. Then, the intermediate frequency signals entering the receiver can be respectively expressed as:

[0067]

[0068] where x a (t) and x s(t) represent the true signal and the spoofing signal respectively, and N a and N s represent the number of satellites included in the signals respectively, P a i and P s i represent the power amplitudes of the two signals respectively, D i (t) is the navigation data code with a value of ±1, τ a i and τ s i are the code phases of the two signals respectively, f0 represents the intermediate frequency value of the signal, f d,a i and f d,s i represent the Doppler frequency offsets of the two signals respectively, φ a i and φ s i are the initial carrier phases of the two signals respectively.

[0069] For the code phase change and the setting of the starting code phase offset point of the spoofing signal, the present invention first determines the approximate deviation range of the target according to the prior position information, so as to set the starting offset point, that is, the code phase deviation. Next, by adjusting the pseudo-code offset speed, the pseudo-code phase of the spoofing signal gradually approaches the true signal:

[0070] τ s i (t) = τ a i (t) + Δτ d + v s * t (4)

[0071] In the formula, Δτ d represents the initial pseudo-range difference, that is, the pseudo-code phase difference. After synchronization, it is towed to the target spoofing position, that is, the target offset point.

[0072] Since asynchronous spoofing cuts into the loop to spoof without the receiver's awareness, when there is asynchronous spoofing, the intermediate frequency signal received by the target receiver will be mixed with the spoofing signal and the true signal:

[0073]

[0074] In the formula, n(t) is the simulated noise, t j represents the moment when the spoofing signal starts to appear in the mixed signal.

[0075] For the power gain of the spoofing signal, it is represented by the parameter α i (t).

[0076]

[0077] In one embodiment, the target receiver simulation parameter configuration set includes parameter configuration sequences under code tracking loop structures corresponding to respective code loop orders; the parameter configuration sequences include pairs of receiver parameters composed of a plurality of loop bandwidths and damping coefficients; the code loop orders include a first-order code tracking loop, a second-order code tracking loop, and a third-order code tracking loop.

[0078] In this embodiment, in the satellite signal processing section, asynchronous spoofing is usually carried out after the receiver enters the tracking stage and involves non-sensing frequency offset. Therefore, the impact on the receiver is mainly reflected in its tracking loop.

[0079] After the GPS intermediate frequency signal enters the tracking loop, the received intermediate frequency signal is first mixed with the locally replicated carrier to achieve carrier stripping, and at the same time, two paths of data, namely the in-phase component (I) and the quadrature component (Q), are generated. As Figure 2 shown in the schematic diagram of the DLL working principle, the code loop will then obtain six integration outputs respectively.

[0080] When there is no spoofing interference, the received signal contains a real satellite signal and a noise signal, and the correlation function between the real pseudo-code and the locally reproduced pseudo-code can be expressed as:

[0081]

[0082] In the formula, τ represents the code phase difference between the real signal and the locally reproduced signal.

[0083] For the correlation function part of the noise component in the signal, as shown in the following formula:

[0084]

[0085] In the formula, n(t) represents the receiver noise, and x a (t) represents the noise introduced by the navigation signal.

[0086] Therefore, the cross-correlation function between the local code of the receiver and the received mixed signal is:

[0087]

[0088] After the signal enters the tracking loop and undergoes correlation operations, the output results of six correlators will be obtained. Taking the prompt code as an example, the outputs of the correlators in the IQ branches are respectively:

[0089]

[0090] In the formula, represents the signal power, Δτ represents the code phase difference between the received signal and the local signal, and Δf d,aIndicates the carrier frequency difference between the navigation signal and the locally replicated signal. Indicates the carrier phase difference between the navigation signal and the locally replicated signal.

[0091] Assume that the carrier phases of the received signal and the local signal are aligned, i.e., sinc(ΔfπT) = 1. The DLL phase detector uses the non-coherent early-late power method, and the output result of the phase detector is as shown in the following formula:

[0092]

[0093] In the formula, I E 、I L 、Q E 、Q L respectively represent the non-coherent integration values of the early branch and the late branch, d represents the correlator spacing, and Δτ represents the phase difference.

[0094] When the code loop is working stably, from the above analysis, it can be seen that the correlation function of the pseudo-random code is symmetric and satisfies So according to formula (11), it can be known that the result ε is 0.

[0095] When the absolute value of the tracking error is greater than the code loop correlator spacing d, it is determined that the code loop has not successfully tracked any valid signal. At this time, the state of the tracking loop is out of lock, the unlock flag is set to 1, and the receiver re-performs acquisition and tracking.

[0096] The GNSS tracking loop is essentially a negative feedback loop composed of a phase detector, a loop filter, and a voltage-controlled oscillator. The basic principle block diagram of the loop filter is as Figure 3 shown. Among them, the first-order loop: when the tracking loop has no loop filter, that is, the transfer function F(s) of the loop filter is a constant coefficient.

[0097]

[0098] In the formula, K represents the loop gain, and w n represents the characteristic frequency.

[0099] Second-order loop: The transfer function F(s) of the loop filter is:

[0100]

[0101] In the formula, τ1 and τ2 respectively represent the time constants of the loop.

[0102] Third-order loop: The transfer function F(s) is expressed as:

[0103]

[0104] In the formula, a3 and b3 represent the filter parameters of the third-order loop.

[0105] When there is spoofing interference, the received signal will have an additional correlation function part of the spoofing signal. At this time, according to the characteristics of the spoofing signal, its correlation function part is as follows:

[0106]

[0107] In the formula, represents the phase difference between the code phase of the spoofing signal and the true signal, and v s represents the pulling velocity of the spoofing signal.

[0108] For the correlation function part of the noise component in the signal, as shown in the following formula:

[0109]

[0110] In the formula, n(t) represents the receiver noise, and x a (t) and x s (t) respectively represent the noise introduced by the true signal and the noise introduced by the spoofing signal.

[0111] Therefore, the cross-correlation function between the local code of the receiver and the received mixed signal is:

[0112]

[0113] After the signal enters the tracking loop and undergoes correlation operation, the output results of six correlators will be obtained. When there is a spoofing signal mixed in the mixed signal, taking the prompt code as an example, the outputs of the correlators in the IQ branches are respectively:

[0114]

[0115] In the formula, and respectively represent the powers of the navigation signal and the spoofing signal, Δτ represents the code phase difference between the received signal and the local signal, and Δf d,a and Δf d,s respectively represent the carrier frequency differences between the true signal and the spoofing signal and the local replica signal, and respectively represent the carrier phase differences between the true signal and the spoofing signal and the local replica signal.

[0116] When there is a spoofing signal, the output result of the phase discriminator will also be affected accordingly:

[0117]

[0118] In the formula, Δτ s represents the deviation of the spoofing signal from the relative pseudo-code phase of the true signal.

[0119] The simulation experiment process is as follows Figure 4 shown, which is divided into two parts: the signal generation part and the signal processing part. In the signal generation part, according to the real navigation signal, the present invention sets the deception signal power, the deception signal pseudo-code time delay (i.e., the code phase pulling range) and the deception entry time of the actual deception scenario to generate a deception signal, and mixes it with the real signal to obtain the mixed signal required for the simulation experiment.

[0120] In the receiver signal processing part, the present invention adjusts the processing flow of the traditional software receiver. First, in the code loop parameter part, the typical parameter configurations of the first-order, second-order, and third-order code loops are traversed; secondly, in the subsequent deception detection stage, a deception detection method is designed for the output result of the code tracking loop to determine whether the asynchronous deception is successful; finally, multiple experiments are carried out and the results are statistically analyzed to obtain the pulling speed threshold. When performing single-channel simulation analysis of the receiver, it is necessary to determine whether the receiver is in a deceived state. Since the positioning solution cannot be performed in the loop stage, it is necessary to determine the detection method when the loop is deceived to determine whether the asynchronous deception successfully pulls the loop. The deception detection process is as follows Figure 5 shown.

[0121] In one embodiment, the simulation parameter configuration set of the target receiver is traversed. According to the current simulation parameters of the target receiver, the target receiver includes: traversing the parameter configuration sequence under the code tracking loop structure corresponding to each code loop order. For the current parameter configuration sequence, each pair of receiver parameters is traversed, and the target receiver simulation configuration is performed according to the current pair of receiver parameters.

[0122] In this embodiment, in a certain traversal, the signal parameter configuration is as follows: the signal point length is 10000 ms, that is, 10 s of signal data. In the first 2000 ms, the navigation signal in the real scenario is simulated. In the time period from 2000 ms to 10000 ms, the receiver processes the navigation signal mixed with the deception signal and the real signal. The specific signal simulation parameters are shown in Table 1 below

[0123] Table 1 Simulation signal parameter configuration information

[0124] Navigation signal carrier-to-noise ratio (dBHz) 45 Signal length (s) 10s Deception signal pseudocode delay (chips) -4—+4 Number of deception signals (paths) Single path

[0125] Receiver loop parameter configuration: The deception experiment results of different loop bandwidths and damping coefficients under the loop structures of the 1st, 2nd, and 3rd order code tracking loops (DLL) are simulated and analyzed. The specific software receiver loop simulation experiment parameters are shown in Table 2 below

[0126] Table 2 Software receiver parameter configuration information

[0127]

[0128] In one embodiment, deception success determination is performed based on the processing result of the hybrid signal by the target receiver, and the corresponding determination result includes: obtaining the correlation peak jump variable of each jump point according to the output result of the tracking code loop of the target receiver. If the correlation peak jump variable is greater than the jump threshold, stability detection is performed on the i-th jump point after the jump point. If the stability detection is passed, it is determined that asynchronous deception is successful; if the stability detection is not passed, it is determined that asynchronous deception fails.

[0129] In this embodiment, the receiver loop generally performs non-coherent processing on the correlation result. Taking the instant code as an example:

[0130]

[0131] After the receiver enters the stable tracking stage, it will be stably locked on the correlation peak of the true signal. Due to the changes in the positions of the satellite and the ground and the changes in the signal propagation environment, the correlation peak on the code loop will jitter around a certain value. Therefore, we use the change rule of this value as the reference data for deception detection for subsequent processing.

[0132] First, calculate the correlation peak change amount of each point as follows:

[0133] ΔP t =P t -P t-1 (23)

[0134] Secondly, compare the relationship between the change amount ΔP and the jump threshold λ. The jump threshold λ is only related to the signal power gain, so it can be obtained through prior experimental tests. If it satisfies the relationship of ΔP t >λ, stability detection is performed on the data after the jump point:

[0135] ΔP t+i+1 -ΔP t <γ (24)

[0136] In the formula, i represents the i-th point after the jump point, and γ represents the threshold for stability judgment. γ is generally set to 3% of the correlation peak. Since the non-coherent integration value is much higher than the noise jump value, 3% is taken to prevent the influence of the noise amount on the stability judgment.

[0137] In one embodiment, guiding the security detection of key infrastructure according to the receiver parameters corresponding to the key infrastructure, the target receiver simulation parameter configuration set, and the spoofing traction speed reference threshold includes: finding the matching parameters of the receiver parameters corresponding to the key infrastructure in the target receiver simulation parameter configuration set, and obtaining the critical value at which the receiver of the key infrastructure is successfully spoofed when encountering spoofing according to the spoofing traction speed reference threshold corresponding to the matching parameters; assisting in optimizing the receiver parameters corresponding to the key infrastructure according to the relationship between the matching parameters and the spoofing traction speed reference threshold.

[0138] In one embodiment, assisting in optimizing the receiver parameters corresponding to the key infrastructure according to the relationship between the matching parameters and the spoofing traction speed reference threshold includes: increasing the spoofing traction speed threshold by increasing the receiver loop bandwidth; when the damping coefficient in the matching parameters shows underdamping, increasing the receiver damping coefficient to increase the spoofing traction speed threshold, and when the damping coefficient shows overdamping, decreasing the receiver damping coefficient to increase the spoofing traction speed threshold; and increasing the spoofing traction speed threshold by increasing the receiver loop order.

[0139] Traverse the typical receiver loop parameters, and the loop parameter design is shown in Table 3 below.

[0140] Table 3 Loop Parameter Settings

[0141]

[0142] For the experimental results, the present invention shows the spoofing results under 36 typical loop structures in the form of multiple subgraphs. Each subgraph represents the spoofing success probability corresponding to three different damping coefficients of the receiver at a fixed loop bandwidth and loop order. All the experimental results are as Figure 6 shown.

[0143] The present invention sets that when the spoofing success rate drops suddenly, the spoofing traction speed corresponding to a 90% success rate is used as our spoofing traction speed reference threshold for analysis. Some results of the speed threshold are shown in Table 4 below:

[0144] Table 4 Spoofing Traction Speed Threshold (Loop Order / Bandwidth)

[0145]

[0146] Observe Figure 6As shown in Table 4, the first, second, and third-order loop bandwidths have the same mechanism for influencing the deceptive pull-in speed threshold. The larger the loop bandwidth, the larger the deceptive pull-in speed threshold, making it easier to control the code loop, thereby deviating from the true tracking point. This pattern is consistent with theory, as the loop bandwidth controls the amount of noise entering the loop. A narrower bandwidth allows fewer frequency components of noise to enter the loop, resulting in better loop filtering and correspondingly stronger signal tracking capabilities. Therefore, as the loop bandwidth increases, the deceptive pull-in speed threshold also increases.

[0147] The loop damping coefficient plays a decisive role in the loop's convergence speed. In the underdamped case (i.e., 0 < & < 1), the phase-locked loop experiences intense oscillations during the step response, resulting in a flexible system response. As the damping coefficient increases, the threshold for deceptive pull-through speed increases accordingly, consistent with theoretical results. In the overdamped case (i.e., & > 1), the phase-locked loop exhibits high stability despite slight oscillations during the input response, as evidenced by a significant decrease in the deceptive pull-through speed threshold.

[0148] As the loop order increases, the deceptive pull-in speed threshold increases. This is because, as can be seen from the loop system function, the loop order affects the loop's dynamic tracking capability. A comparative analysis of first- and second-order loop structures shows that if a frequency ramp excitation is added while both are tracking stably, the first-order loop will lose lock because it can only track a frequency step excitation at best. This characteristic makes higher-order loops more stable, thus creating a higher speed threshold for asynchronous deception.

[0149] In one embodiment, under the same loop structure, analyzing the parameter threshold range for successful deception of spoofing signals is of great significance for guiding future navigation. The loop structure is set to a first-order code loop, the loop bandwidth is 25Hz, the damping coefficient is set to 0.7071, and the spoofing signal power gain is set from 2dB to 9dB. The experimental results are shown in Figure 2. Figure 7 As shown, observe Figure 7 As can be seen, as the power gain increases, the deception pull speed threshold also increases. Combining the asynchronous deception process, it can be seen that with higher deception power, the correlation peak of the deception signal is much higher than the true navigation signal, allowing it to seize the loop faster. Therefore, its pull speed is greater than that of low-power pull.

[0150] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in the present invention, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Figure 1At least some of the steps may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least some of the sub-steps or stages of other steps or other steps.

[0151] In one embodiment, as Figure 8 shown, an asynchronous traction type spoofing threshold test device for critical infrastructure is provided, including:

[0152] A signal simulation module 802, configured to configure a spoofing signal according to pre-set spoofing signal simulation parameters, and obtain a mixed signal based on the spoofing signal and a navigation satellite signal; the spoofing signal simulation parameters include a starting offset point, a target offset point, a pseudo-code offset speed, a signal power gain, and a spoofing entry time; the spoofing signal is used to implement asynchronous traction type spoofing;

[0153] A receiver simulation module 804, configured to traverse a pre-set set of target receiver simulation parameter configurations, configure a target receiver according to the current target receiver simulation parameters, input the mixed signal into the target receiver, and determine whether spoofing is successful based on the processing result of the target receiver for the mixed signal to obtain a corresponding determination result; the target receiver simulation parameters include a code loop order, a loop bandwidth, and a damping coefficient;

[0154] A threshold acquisition module 806, configured to count each determination result to obtain a spoofing success rate under each target receiver simulation parameter configuration, and obtain a spoofing traction speed reference threshold according to the spoofing traction speed corresponding to a pre-set spoofing success rate;

[0155] A security detection module 808, configured to guide the critical infrastructure to perform security detection according to the receiver parameters corresponding to the critical infrastructure, the set of target receiver simulation parameter configurations, and the spoofing traction speed reference threshold.

[0156] In one of the embodiments, it is further configured to find matching parameters of the receiver parameters corresponding to the critical infrastructure in the set of target receiver simulation parameter configurations, obtain a critical value at which the receiver of the critical infrastructure is successfully spoofed when encountering spoofing according to the spoofing traction speed reference threshold corresponding to the matching parameters; and assist in optimizing the receiver parameters corresponding to the critical infrastructure according to the relationship between the matching parameters and the spoofing traction speed reference threshold.

[0157] In one embodiment, it is further used to increase the spoofing pulling speed threshold by increasing the receiver loop bandwidth; when the damping coefficient in the matching parameters shows underdamping, increase the receiver damping coefficient to increase the spoofing pulling speed threshold, and when the damping coefficient shows overdamping, decrease the receiver damping coefficient to increase the spoofing pulling speed threshold; and increase the spoofing pulling speed threshold by increasing the receiver loop order.

[0158] In one embodiment, it is further used to obtain the correlation peak jump variable of each jump point according to the tracking code loop output result of the target receiver. If the correlation peak jump variable is greater than the jump threshold, perform stability detection on the i-th jump point after the jump point. If the stability detection is passed, it is determined that the asynchronous spoofing is successful; if the stability detection is not passed, it is determined that the asynchronous spoofing fails.

[0159] In one embodiment, it is further used to set the spoofing entry time of the spoofing signal as the time when the spoofing signal starts to appear in the mixed signal; determine the deviation range according to the prior position information of the target receiver, and set the starting pull-off point of the spoofing signal according to the deviation range; set the pseudo-code pull-off speed of the spoofing signal according to the pseudo-code phase difference, the spoofing signal and the code phase of the navigation satellite signal; set the target pull-off point of the spoofing signal according to the actual requirements; set the signal power gain of the spoofing signal according to the power amplitudes of the spoofing signal and the navigation satellite signal; configure the spoofing signal according to the starting pull-off point, the target pull-off point, the pseudo-code pull-off speed, the spoofing entry time and the signal power gain.

[0160] In one embodiment, the target receiver simulation parameter configuration set further includes a parameter configuration sequence under the code tracking loop structure corresponding to each code loop order; the parameter configuration sequence includes a pair of receiver parameters composed of several loop bandwidths and damping coefficients; the code loop orders include a first-order code tracking loop, a second-order code tracking loop and a third-order code tracking loop.

[0161] In one embodiment, it is further used to traverse the target receiver simulation parameter configuration set and configure the target receiver according to the current target receiver simulation parameters, including: traversing the parameter configuration sequence under the code tracking loop structure corresponding to each code loop order, for the current parameter configuration sequence, traversing each pair of receiver parameters, and performing target receiver simulation configuration according to the current pair of receiver parameters.

[0162] For the specific limitations of the asynchronous traction deception threshold test device for critical infrastructure, reference can be made to the limitations of the asynchronous traction deception threshold test method for critical infrastructure in the above text, which will not be elaborated here. Each module in the above asynchronous traction deception threshold test device for critical infrastructure can be implemented in whole or in part by software, hardware, or a combination thereof. The above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0163] In one embodiment, a computer device is provided. The computer device can be a terminal, and its internal structure diagram can be as Figure 9 shown. The computer device includes a processor, a memory, a network interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements an asynchronous traction deception threshold test method for critical infrastructure. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer covering the display screen, or a button, a trackball, or a touchpad provided on the housing of the computer device, or an external keyboard, a touchpad, or a mouse, etc.

[0164] Those skilled in the art can understand that Figure 9 the structure shown in

[0165] is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0166] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the method in the above embodiment.

[0167] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the embodiments provided in the present application can include non-volatile and / or volatile memories. Non-volatile memories can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memories can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0168] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0169] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. An asynchronous traction type deception threshold test method for key infrastructure, characterized in that, The method includes: Configuring a spoofing signal according to pre-set spoofing signal simulation parameters, and obtaining a mixed signal based on the spoofing signal and a navigation satellite signal; the spoofing signal simulation parameters include a starting offset point, a target offset point, a pseudo-code offset speed, a signal power gain, and a spoofing entry time; the spoofing signal is used to implement asynchronous traction spoofing; Traversing a pre-set target receiver simulation parameter configuration set, configuring a target receiver according to the current target receiver simulation parameters, inputting the mixed signal into the target receiver, and determining spoofing success based on the processing result of the target receiver on the mixed signal to obtain a corresponding determination result; the target receiver simulation parameters include a code loop order, a loop bandwidth, and a damping coefficient; Counting each determination result to obtain the spoofing success rate under each target receiver simulation parameter configuration, and obtaining a spoofing traction speed reference threshold according to the spoofing traction speed corresponding to the pre-set spoofing success rate; Guiding the security detection of key infrastructure according to the receiver parameters corresponding to the key infrastructure, the target receiver simulation parameter configuration set, and the spoofing traction speed reference threshold; The determining spoofing success based on the processing result of the target receiver on the mixed signal to obtain a corresponding determination result includes: Obtaining the correlation peak jump variable of each jump point according to the tracking code loop output result of the target receiver. If the correlation peak jump variable is greater than the jump threshold, perform stability detection on the i-th jump point after the jump point. If the stability detection is passed, it is determined that asynchronous spoofing is successful; If the stability detection is not passed, it is determined that asynchronous spoofing fails.

2. The method according to claim 1, wherein Guiding the security detection of key infrastructure according to the receiver parameters corresponding to the key infrastructure, the target receiver simulation parameter configuration set, and the spoofing traction speed reference threshold includes: Searching for the matching parameters of the receiver parameters corresponding to the key infrastructure in the target receiver simulation parameter configuration set, and obtaining the critical value at which the receiver of the key infrastructure is successfully spoofed when encountering spoofing according to the spoofing traction speed reference threshold corresponding to the matching parameters; Assisting in optimizing the receiver parameters corresponding to the key infrastructure according to the relationship between the matching parameters and the spoofing traction speed reference threshold.

3. The method according to claim 2, wherein Assisting in optimizing the receiver parameters corresponding to the key infrastructure according to the relationship between the matching parameters and the spoofing traction speed reference threshold includes: Increasing the receiver loop bandwidth to increase the spoofing traction speed threshold; When the damping coefficient in the matching parameters shows underdamping, increasing the receiver damping coefficient to increase the spoofing traction speed threshold. When the damping coefficient shows overdamping, decreasing the receiver damping coefficient to increase the spoofing traction speed threshold; And increasing the receiver loop order to increase the spoofing traction speed threshold.

4. The method according to claim 1, characterized in that Configuring a spoofing signal according to pre-set spoofing signal simulation parameters includes: Setting the moment when the spoofing signal starts to appear in the mixed signal as the spoofing entry time of the spoofing signal; Determining a deviation range according to the prior position information of the target receiver, and setting the starting offset point of the spoofing signal according to the deviation range; Setting the pseudo-code offset speed of the spoofing signal according to the pseudo-code phase difference, the code phase of the spoofing signal, and the code phase of the navigation satellite signal; Set the target offset point of the spoofing signal according to the actual requirements; Set the signal power gain of the spoofing signal according to the power amplitudes of the spoofing signal and the navigation satellite signal; Configure the spoofing signal according to the starting offset point, target offset point, pseudo-code offset speed, spoofing entry time, and signal power gain.

5. The method according to claim 1, wherein The target receiver simulation parameter configuration set includes parameter configuration sequences under the code tracking loop structures corresponding to each code loop order; the parameter configuration sequences include pairs of receiver parameters composed of a number of loop bandwidths and damping coefficients; the code loop orders include a first-order code tracking loop, a second-order code tracking loop, and a third-order code tracking loop.

6. The method according to claim 5, characterized in that, Traverse the target receiver simulation parameter configuration set, and configure the target receiver according to the current target receiver simulation parameters, including: Traverse the parameter configuration sequences under the code tracking loop structures corresponding to each code loop order. For the current parameter configuration sequence, traverse each pair of receiver parameters, and perform target receiver simulation configuration according to the current pair of receiver parameters.

7. An asynchronous traction type deception threshold test device for critical infrastructure applied to the method according to any one of claims 1-6, characterized in that, The device includes: A signal simulation module, configured to configure a spoofing signal according to pre-set spoofing signal simulation parameters, and obtain a mixed signal based on the spoofing signal and the navigation satellite signal; the spoofing signal simulation parameters include a starting offset point, a target offset point, a pseudo-code offset speed, a signal power gain, and a spoofing entry time; the spoofing signal is used to implement asynchronous towing spoofing; A receiver simulation module, configured to traverse a pre-set target receiver simulation parameter configuration set, configure the target receiver according to the current target receiver simulation parameters, input the mixed signal into the target receiver, determine whether spoofing is successful based on the processing result of the target receiver for the mixed signal, and obtain a corresponding determination result; the target receiver simulation parameters include the code loop order, loop bandwidth, and damping coefficient; A threshold acquisition module, configured to count the spoofing success rates under each target receiver simulation parameter configuration based on each determination result, and obtain a spoofing towing speed reference threshold according to the spoofing towing speed corresponding to a pre-set spoofing success rate; A security detection module, configured to guide the security detection of critical infrastructure according to the receiver parameters corresponding to the critical infrastructure, the target receiver simulation parameter configuration set, and the spoofing towing speed reference threshold.

8. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method according to any one of claims 1 to 6.

Images