A method for generating a spoofing traction code against TOA detection and power detection

Abstract

The application relates to a method for generating a deception leading code resisting TOA detection and power detection, and the acquisition steps of the deception leading code are as follows: S1, determining a leading rate; S2, calculating an expected leading code phase; S3, calculating a required ; S4, calculating a leading code sequence of each. The local code is correlated with a real signal and a deception signal respectively, the local time is followed by a leading correlation peak, with the passing of the leading phase, the actual received correlation peak of the receiver is always in the shape of an ideal correlation peak, on the basis of which, the code phase will be gradually changed at the leading rate on the basis of the real code phase, the baseband signal power received by the deceived party is constant, so the baseband signal will not have power mutation.

Description

Technical Field

[0001] This invention belongs to the field of satellite navigation interference and anti-interference technology, specifically relating to a method for generating deceptive towing codes to resist TOA detection and power detection. Background Technology

[0002] In the field of anti-spoofing, receivers have numerous defensive measures that can be equipped with. Domestic and international scholars have mainly focused their research on spoofing interference detection on five aspects: satellite signal power detection, satellite signal angle of arrival detection, satellite signal time of arrival detection, consistency verification detection, and satellite signal encryption authentication detection.

[0003] The design principle of the deception towing process directly determines the success and concealment of the deception. Faced with increasingly sophisticated defenses, deception methods also need to be continuously upgraded. Based on the drawbacks of traditional towing methods being easily detected by TOA and power detection, this paper proposes a special method for generating deception towing codes. This is an alternative to traditional towing strategies and can bypass the receiver's TOA and power detection. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems. This application proposes a deceptive towing code generation method that resists TOA detection and power detection, which improves the traditional deceptive towing process and enables the deceptive signal to bypass the receiver's TOA detection and power detection.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for generating a deceptive towing code resistant to TOA detection and power detection, wherein the steps for obtaining the deceptive towing code are as follows:

[0006] S1. Determine the traction rate ;

[0007] S2, Calculate the expected traction code phase. ;

[0008] S3, Calculation required ;

[0009] S4, calculate each traction code sequence ;

[0010] Specifically, the correlation results between the real PRN and the local PRN are defined as follows: In the case of incomplete deception, both true and false signals will be correlated with the local PRN. This correlation result is defined as... Ignoring noise, the correlation function is:

[0011]

[0012] Because the total correlation peak received by the receiver is ,expect It is the ideal shape of the correlation peak, and the traction receiver only needs the moving code phase.

[0013]

[0014] in It is the code phase traction rate. It is the ideal correlation peak;

[0015] From the expected Based on the relevant theorems of Fourier transform, the formula for calculating the traction code sequence can be derived:

[0016] .

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] This invention correlates the local code with the real signal and the spoofed signal respectively, and the local code will constantly follow the traction correlation peak. As the pulling phase shifts, the correlation peak actually received by the receiver... It always maintains the shape of an ideal correlation peak. Based on this, the code phase will stably increase from the true code phase. The traction rate changes gradually, so there will be no abrupt changes in the observed values ​​or distortion of the correlation peaks, thus bypassing the receiver's TOA detection. Simultaneously, due to the correlation peaks... Unlike the distorted correlation peaks obtained by superimposing correlation peaks from traditional traction, this method uses a special traction code to suppress part of the real navigation signal power, ensuring that the baseband signal power received by the deceived party remains constant. Therefore, there will be no power abrupt change in the baseband signal, which can bypass the receiver's power detection. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only for more clearly illustrating the technical solutions in the embodiments of the present invention or the prior art. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 Demonstration results of sudden changes in baseband signal power;

[0021] Figure 2 Classification of satellite signal time of arrival detection;

[0022] Figure 3 The results demonstrate the carrier-Doppler transition.

[0023] Figure 4 This demonstrates the distortion results of traditional traction-related peaks.

[0024] Figure 5 This is a flowchart of the steps for obtaining the deceptive traction code in this invention;

[0025] Figure 6 This is a schematic diagram illustrating the morphological changes of the pseudocode sequence at the transceiver end of the present invention.

[0026] Figure 7 This is a schematic diagram illustrating the morphological changes of the autocorrelation function of the traction code in this invention;

[0027] Figure 8 This is a schematic diagram of the deceptive traction correlation peak (time 1) for the anti-correlation distortion detection of the present invention;

[0028] Figure 9 This is a schematic diagram of the deceptive traction correlation peak (time 2) for the anti-correlation distortion detection of the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific embodiments. However, the embodiments are only for illustration and are not intended to limit the present invention.

[0030] The design principle of the deception towing process directly determines the success and concealment of the deception. Faced with increasingly sophisticated defenses, deception methods also need to be constantly upgraded. Based on the drawbacks of traditional towing methods being easily detected by TOA and power detection, this invention proposes a special method for generating deception towing codes, which, unlike traditional towing methods, can bypass the receiver's TOA and power detection.

[0031] Domestic and international scholars have mainly focused their research on deception and interference detection in five aspects: satellite signal power detection, satellite signal angle of arrival detection, satellite signal time of arrival detection, consistency verification detection, and satellite signal encryption authentication detection. Table 1 shows typical detection methods for each detection type.

[0032] Table 1 Types of Spoofing Detection

[0033]

[0034] Traditional traction spoofing requires the spoofing signal to have a power advantage over the real signal, which inevitably increases the power at the receiving end. The presence of spoofing can be determined by monitoring the signal power. Figure 1 This is a demonstration result of a sudden change in baseband signal power.

[0035] During the process of the correlation peaks in a traction spoofing attack moving, aligning, and then moving away, the correlation peaks of the real signal and the spoofed signal collide, distorting the correlation peak envelope received by the receiver. Consequently, the parameters received by the spoofed target also exhibit abnormal changes. Therefore, satellite signal time of arrival (TOA) detection, like signal power detection, is an important method for detecting traction spoofing. Satellite signal time of arrival (TOA) detection can be divided into observational abrupt change detection and signal correlation distortion detection.

[0036] Figure 2 Classification of satellite signal time of arrival (TOA) detection.

[0037] like Figure 3 The diagram shown illustrates the results of a carrier-Doppler jump demonstration. The observed objects that can cause a sudden change in measurement may include information such as code frequency, Doppler amplitude, and pseudorange. By fitting these observations and calculating the fitting residual statistics, it is possible to determine whether a jump exists and thus detect spoofing.

[0038] Signal correlation distortion detection involves analyzing the correlator output or signal quality of the signal received by a GNSS receiver to detect deception interference. Correlator output analysis detects deception interference by observing abnormalities in the correlation curve, such as broadening of the correlation peak width or an increase in the number of peaks. Corresponding detection methods include the correlation peak half-width at half-maximum (FWHM) method, the correlation function width threshold method, and multi-peak detection. Signal quality analysis detects deception interference by observing severe symmetrical distortions in the correlation curve; this method is often referred to as signal quality monitoring (SQM). The traditional traction correlation peak distortion demonstration results are shown below. Figure 4 As shown.

[0039] like Figure 5 As shown, in this invention, the steps for obtaining the deceptive traction code are as follows:

[0040] S1. Determine the traction rate ;

[0041] S2, Calculate the expected traction code phase ;

[0042] S3, Calculation required ;

[0043] S4, Calculation traction code sequence ;

[0044] Specifically, the correlation results between the real PRN and the local PRN are defined as follows: In the case of incomplete deception, both true and false signals will be correlated with the local PRN. This correlation result is defined as... Ignoring noise, the correlation function is:

[0045]

[0046] Because the total correlation peak received by the receiver is ,expect It is the ideal shape of the correlation peak, and the traction receiver only needs the moving code phase.

[0047]

[0048]

[0049] in It is the code phase traction rate. It is the ideal correlation peak;

[0050] From the expected Based on the relevant theorems of Fourier transform, the formula for calculating the traction code sequence can be derived:

[0051]

[0052] like Figure 6 The figures show the initial (a), intermediate (b), and final (c) forms of the towing code and the pseudo-code sequence received by the deceived party. It can be seen that the towing code changes constantly as the towing process progresses, without a fixed form, and is not a pseudo-code in the traditional sense. Furthermore, it can be seen that after processing using the method of this invention, the pseudo-code received by the deceived party exhibits a significant phase shift. Before and after towing, the pseudo-code at the receiving end is still the PRN code of the satellite, but the code Doppler adds an extra layer to the real Doppler. In the design of the computation process, the pseudocode is calculated in real time, so the phase is continuous.

[0053] Figure 7 The diagram shows the change process of the autocorrelation function of the traction code. It can be seen that it does not have stable and good autocorrelation characteristics and is not the same type of Gold code as the real navigation signal.

[0054] The local code is correlated with both the real and deceptive signals, and the local signal will constantly follow the relevant peaks. ,Depend on Figure 8 , 9 It can be seen that as the pulling phase shifts, the correlation peak actually received by the receiver... It always maintains the shape of an ideal correlation peak. Based on this, the code phase will stably increase from the true code phase. The traction rate changes gradually, so there will be no abrupt changes in the observation and distortion of the related peaks, which can bypass the receiver's TOA detection.

[0055] At the same time, due to the related peak Different from Figure 4The distorted correlation peaks obtained by superimposing the correlation peaks of traditional traction are actually suppressed by the special traction code of this invention, which suppresses part of the real navigation signal power and ensures that the baseband signal power received by the deceived party is constant. Therefore, there will be no power change in the baseband signal, which can bypass the power detection of the receiver.

[0056] All content not described in detail in this invention is prior art.

[0057] The above description is merely a preferred embodiment of the present invention and is not limited to the description in the specification and embodiments. Therefore, all equivalent changes or modifications made to the structure, features, and principles described in the claims of this invention should be included within the scope of this patent application.

Claims

1. A method for generating spoofed torsion codes resistant to TOA detection and power detection, characterized in that: A special deception torrent code was generated to replace the fake code in the original signaling system. The steps to obtain this torrent code are as follows: S1. Determine the traction rate ; S2, Calculate the expected traction code phase. ; S3, Calculation required ; S4, calculate each traction code sequence ; Specifically, the correlation results between the real PRN and the local PRN are defined as follows: In the case of incomplete deception, both true and false signals will be correlated with the local PRN. This correlation result is defined as... Ignoring noise, the correlation function is: Because the total correlation peak received by the receiver is ,expect It is the ideal shape of the correlation peak, and the traction receiver only needs the moving code phase. in It is the code phase traction rate. It is the ideal correlation peak; From the expected Based on the relevant theorems of Fourier transform, the formula for calculating the traction code sequence can be derived: 。

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