A method, system and device for spoofing identification suppression based on dual tracking channel RAIM
By employing the dual-tracking channel RAIM method, satellite signals are acquired and channel is allocated in a dual-peak manner, which solves the problem of spoofing signals outweighing real signals in the receiver, thus ensuring the accuracy and reliability of positioning and timing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUN YAT SEN UNIV
- Filing Date
- 2023-08-25
- Publication Date
- 2026-07-24
Smart Images
Figure CN117148386B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of anti-jamming technology for navigation receivers, and in particular to a spoofing identification and suppression method, system and device based on dual-tracking channel RAIM. Background Technology
[0002] At the navigation receiver end, based on the objectives of spoofing interference protection, anti-spoofing technologies can be categorized into four levels: spoofing interference detection, spoofing interference identification, spoofing interference suppression, and spoofing interference countermeasures. Currently, most research on anti-spoofing focuses on the spoofing detection stage. However, for the receiver, the more important aspect is how to identify and suppress spoofing interference signals, ensuring that the receiver maintains reliable positioning and timing results even under spoofing interference.
[0003] Receiver Autonomous Integrity Monitoring (RAIM), as a terminal signal processing method, detects and eliminates faulty satellites based on the consistency of pseudorange measurements from various satellites. If spoofing interference signals are considered as signals from faulty satellites, the RAIM algorithm can also be used to identify and suppress these signals.
[0004] When the number of real signals captured and tracked by the receiver exceeds the number of spoofing signals, the RAIM algorithm can achieve the desired effect in spoofing identification and suppression. However, since the RAIM algorithm eliminates signals based on the consistency of pseudorange measurements, it may incorrectly eliminate real signals when spoofing signals dominate, which is not conducive to obtaining accurate and reliable positioning and timing results. Summary of the Invention
[0005] The technical problem this invention aims to solve is how to maintain accurate positioning and timing results even when the receiver captures more spoofed signals than genuine signals. To address this problem, this invention provides a spoofing identification and suppression method, system, and device based on dual-tracking-channel RAIM.
[0006] In a first aspect, embodiments of the present invention provide a spoofing identification and suppression method based on dual-tracking-channel RAIM, comprising:
[0007] The signal from each visible satellite is captured using a dual-peak acquisition method to obtain the highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite.
[0008] A primary tracking channel is allocated to the highest peak satellite signal, and a secondary tracking channel is allocated to the second highest peak satellite signal;
[0009] After stable tracking, calculate the pseudorange observations of all visible satellites in the secondary tracking channel;
[0010] Global RAIM is performed on the pseudorange observations to determine whether the global RAIM passes. If it passes, PVT is performed based on the pseudorange observations to obtain the actual navigation, positioning, and timing results.
[0011] Preferably, determining whether the global RAIM passes further includes:
[0012] If global RAIM fails, all possible subsets of deceiving satellites are listed. The pseudorange observations of the first subset are removed from the pseudorange observations. Subset RAIM is then performed on the remaining pseudorange observations. It is determined whether the subset RAIM passes. If it fails, the pseudorange observations of the next subset are removed from the pseudorange observations. The subset RAIM is then performed on the remaining pseudorange observations until the subset RAIM passes. PVT is then performed based on the remaining pseudorange observations to obtain the true navigation, positioning, and timing results.
[0013] Preferably, the step of performing bimodal acquisition on the signal of each visible satellite to obtain the highest peak satellite signal and the second highest peak satellite signal of the acquired visible satellite includes:
[0014] The signal of each visible satellite is searched from three dimensions: PRN code, pseudo-code phase, and carrier Doppler frequency shift. Satellite signals that achieve the maximum value and exceed the acquisition threshold in the two-dimensional correlation result of pseudo-code phase-carrier Doppler frequency shift, and satellite signals that achieve the second maximum value and exceed the acquisition threshold are captured. The highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite are obtained respectively.
[0015] Preferably, the step of performing global RAIM on the pseudorange observations includes:
[0016] Based on the pseudorange observations, the receiver position estimate is obtained using the least squares method.
[0017] Based on the pseudorange observations and the receiver position estimate, the pseudorange residual is obtained;
[0018] The test statistic for the sum of squares of the pseudo-range residuals is obtained based on the pseudo-range residuals.
[0019] Determine whether the test statistic does not exceed the detection threshold. If it does not, the global RAIM passes.
[0020] Preferably, after performing PVT calculation based on the pseudorange observations to obtain the actual navigation, positioning, and timing results, the method further includes:
[0021] Calculate the pseudorange observations for all satellites within the main tracking channel;
[0022] Global RAIM is performed on the pseudorange observations of all satellites in the main tracking channel. It is then determined whether the global RAIM passes. If the global RAIM passes, PVT is performed based on the pseudorange observations of all satellites in the main tracking channel to obtain the navigation, positioning, and timing results of the spoofing signal.
[0023] Preferably, determining whether the global RAIM passes further includes:
[0024] If global RAIM fails, then all possible subsets of real satellites are listed. The pseudorange observations of the first subset are removed from the pseudorange observations of all satellites in the main tracking channel. Subset RAIM is then performed on the remaining pseudorange observations. If the subset RAIM fails, the pseudorange observations of the next subset are removed from the pseudorange observations of all satellites in the main tracking channel. This process of performing subset RAIM on the remaining pseudorange observations continues until the subset RAIM passes. PVT is then performed based on the remaining pseudorange observations to obtain the navigation, positioning, and timing results for the spoofed signal.
[0025] Secondly, embodiments of the present invention also provide a spoofing identification and suppression system based on dual-tracking-channel RAIM, comprising:
[0026] The dual-peak acquisition module is used to acquire the signal of each visible satellite in a dual-peak manner, obtaining the highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite;
[0027] A dual-channel tracking module is used to allocate a primary tracking channel for the highest peak satellite signal and a secondary tracking channel for the second highest peak satellite signal;
[0028] The pseudorange observation calculation module is used to calculate the pseudorange observations of all visible satellites in the secondary tracking channel after stable tracking.
[0029] The secondary channel RAIM test module is used to perform global RAIM on the pseudorange observations, determine whether the global RAIM passes, and if it passes, perform PVT calculation based on the pseudorange observations to obtain the actual navigation, positioning and timing results.
[0030] Preferably, the secondary channel RAIM test module further includes:
[0031] The subset RAIM module is used to enumerate all possible subsets of satellites to deceive if global RAIM fails. It then removes the pseudorange observations of the satellites in the first subset from the pseudorange observations, performs subset RAIM on the remaining pseudorange observations, and determines whether the subset RAIM passes. If it fails, it removes the pseudorange observations of the satellites in the next subset from the pseudorange observations, and continues performing subset RAIM on the remaining pseudorange observations until the subset RAIM passes. Finally, it performs PVT calculation based on the remaining pseudorange observations to obtain the true navigation, positioning, and timing results.
[0032] Preferably, it further includes:
[0033] The main channel RAIM test module is used to calculate the pseudorange observations of all satellites in the main tracking channel, perform global RAIM on the pseudorange observations of all satellites in the main tracking channel, and determine whether the global RAIM passes. If the global RAIM passes, PVT calculation is performed based on the pseudorange observations of all satellites in the main tracking channel to obtain the navigation, positioning, and timing results of the spoofing signal.
[0034] Thirdly, embodiments of the present invention also provide a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor executes the computer program to implement the spoofing identification and suppression method as described above.
[0035] Compared with existing technologies, the spoofing identification and suppression method, system, and device based on dual-tracking-channel RAIM proposed in this invention have the following advantages: The dual-tracking-channel receiver used in this invention employs a dual-peak acquisition algorithm and uses two channels to track a satellite. As long as the received signal still contains a real signal, the correct positioning and timing results can be maintained. At the implementation level, the dual-tracking-channel receiver essentially adds a tracking channel to the existing structure of a traditional receiver, making it relatively easy to implement. Attached Figure Description
[0036] Figure 1 This is a flowchart illustrating a spoofing identification and suppression method based on dual-tracking channel RAIM according to an embodiment of the present invention.
[0037] Figure 2 This is a schematic diagram of the tracking process of the main tracking channel and the secondary tracking channel in an embodiment of the present invention.
[0038] Figure 3 This is a schematic diagram illustrating all possible subsets of deceiving satellites according to an embodiment of the present invention.
[0039] Figure 4 This is a schematic diagram of a spoofing identification and suppression system based on dual-tracking channel RAIM according to an embodiment of the present invention.
[0040] Figure 5 This is a schematic diagram of the structure of the RAIM module, a subset of the present invention.
[0041] Figure 6 This is a schematic diagram of the main channel RAIM test module in an embodiment of the present invention.
[0042] Figure 7 This is a schematic diagram of the structure of a terminal device according to an embodiment of the present invention. Detailed Implementation
[0043] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.
[0044] In the description of this invention, it should be understood that the method and system of this invention are mainly applied to receivers.
[0045] like Figure 1 As shown, this embodiment of the invention provides a spoofing identification and suppression method based on dual-tracking channel RAIM, including the following steps:
[0046] S1. Perform bimodal acquisition on the signal of each visible satellite to obtain the highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite;
[0047] In traditional receivers, during the acquisition phase, the satellite signal that achieves the maximum value in the pseudo-code phase-carrier Doppler frequency shift two-dimensional correlation result for the same satellite and exceeds the acquisition threshold is considered the acquisition result. Then, during the tracking phase, a single channel is used to track one satellite. Generally, when spoofing signals are present, the pseudo-code phase-carrier Doppler frequency shift two-dimensional correlation result will have two peaks. Due to the power advantage of the spoofing signal, the receiver will acquire and track the spoofing signal, resulting in the receiver tracking mostly spoofing signals.
[0048] To overcome the shortcomings of traditional receivers' single-peak acquisition, this embodiment searches for the signal of each visible satellite in three dimensions during the acquisition phase: PRN code, pseudo-code phase, and carrier Doppler shift. Satellite signals that achieve the maximum value and exceed the acquisition threshold in the two-dimensional correlation result of pseudo-code phase and carrier Doppler shift, and satellite signals that achieve the second maximum value and exceed the acquisition threshold, are acquired. This yields the highest peak satellite signal and the second highest peak satellite signal of the acquired visible satellites, respectively. Through dual-peak acquisition—that is, capturing both the peak values corresponding to the deceptive signals and the true signals of the acquired satellites—the receiver can ensure that it captures all deceptive and true signals.
[0049] S2. Allocate a primary tracking channel for the highest peak satellite signal and a secondary tracking channel for the second highest peak satellite signal;
[0050] During the tracking phase, the receiver uses the main tracking channel to track the satellite signal at the highest peak and the secondary tracking channel to track the satellite signal at the next highest peak. Specifically, the tracking process is as follows: the intermediate frequency (IF) carrier is stripped from the satellite signal using a correlator; an integration-clearing operation is performed on the IF carrier to obtain a coherent integration result; this coherent integration result is input into a phase detector to obtain a phase detection result; the phase detection result is then input into a loop filter for filtering to obtain a filtered phase detection result; and the carrier NCO and code NCO adjust the local carrier and local pseudo-code based on the filtered phase detection result. For details of the above tracking process, please refer to [link to relevant documentation]. Figure 2 .
[0051] S3. After stabilizing tracking, calculate the pseudorange observations of all visible satellites in the secondary tracking channel;
[0052] In reality, most satellite signals in the primary tracking channel are deceptive, while most satellite signals in the secondary tracking channel are genuine. After stable tracking, calculating the pseudorange observations of all visible satellites in the secondary tracking channel is beneficial for obtaining accurate navigation, positioning, and timing results. Specifically, the process of calculating the pseudorange observations is as follows:
[0053] Suppose that observation data from n visible satellites are received at a certain moment, then the pseudorange observation equation is expressed as follows:
[0054] ρ=Hx+ε
[0055] Where ρ represents the n-dimensional pseudorange observation, H represents the n*4-dimensional observation matrix, x represents the receiver state vector, including the three-dimensional position and receiver clock offset, and ε represents the n-dimensional measurement error vector, which follows a mean of 0 and a variance of σ. 2 .
[0056] S4. Perform global RAIM on the pseudorange observations and determine whether the global RAIM passes. If it passes, perform PVT calculation based on the pseudorange observations to obtain the true navigation, positioning and timing results.
[0057] Specifically, the process of performing global RAIM on pseudorange observations is as follows:
[0058] Based on the pseudorange observations, the receiver position estimate is obtained using the least squares method, as expressed in the following formula:
[0059] x ls =(H T H) -1 H T ρ
[0060] Where, x ls This represents the receiver's position estimate.
[0061] Based on the pseudorange observations and receiver position estimates, the pseudorange residual is obtained, as expressed by the following formula:
[0062] z = ρ - ρx ls =[IH(H T H) -1 H T ]ρ
[0063] Where z represents the pseudo-range residual. Further, in this embodiment, S = IH(H T H) -1 H T Let S denote the residual sensitivity matrix. Then, the formula for the pseudorange residual z can be rewritten as follows:
[0064] z=Sρ
[0065] Verification shows that the residual sensitivity matrix S is a symmetric matrix and an idempotent matrix, i.e., S0 2 =S. Therefore, knowing the observation matrix H, the residual sensitivity matrix S can be calculated, thus eliminating the need to calculate the receiver position estimate x. ls The pseudorange residual z can then be calculated directly. After obtaining the pseudorange residual z, the sum of squares of the pseudorange residuals is calculated, as shown in the following formula:
[0066] SSE = z T z
[0067] Here, SSE represents the sum of squared pseudo-range residuals. SSE has a simple form and low computational complexity.
[0068] The test statistic for the sum of squares of pseudorange residuals (SSE) is obtained from the pseudorange residuals. Since the observation noise in the pseudorange observations of n satellites is zero-mean Gaussian white noise and they are independent of each other, the SSE of pseudorange residuals follows a chi-square distribution with n-4 degrees of freedom. Its test statistic is expressed as follows:
[0069]
[0070] in, This represents the test statistic.
[0071] The test statistic is checked to see if it does not exceed the detection threshold. If it does, the global RAIM passes. When the GNSS navigation system is working normally, the pseudorange residuals are small, and the test statistic is also small. When a visible satellite malfunctions, its measured pseudorange will have a large deviation, and the test statistic will also increase, requiring fault detection. Specifically, this embodiment compares the test statistic with the detection threshold. If the test statistic is not greater than the detection threshold, it indicates that the system is not faulty, there is no spoofing signal in the secondary tracking channel, and the global RAIM passes.
[0072] If the global RAIM passes, then PVT calculation is performed based on the pseudorange observations to obtain the actual navigation, positioning, and timing results. This embodiment uses the same technical means as existing PVT calculations for PVT calculation based on pseudorange observations, and will not be described further here.
[0073] Furthermore, if the test statistic exceeds the detection threshold, it indicates a system fault, a deception signal exists in the secondary tracking channel, and global RAIM fails. If global RAIM fails, all possible subsets of deception satellites are listed. The pseudorange observations of the satellites in the first subset are removed from the pseudorange observations. Subset RAIM is then performed on the remaining pseudorange observations to determine if it passes. If it fails, the pseudorange observations of the satellites in the next subset are removed from the pseudorange observations, and subset RAIM is continued on the remaining pseudorange observations until it passes. PVT calculation is then performed based on the remaining pseudorange observations to obtain the true navigation, positioning, and timing results. This embodiment lists all possible subsets of deception satellites (SPs). k ,like Figure 3 As shown, the numbers in the circles represent satellite numbers, and the subsets are arranged in ascending order of the number of spoofed satellites. First, k=1 is chosen, and subset SP is removed from the pseudorange observations. k The pseudorange observations of the included satellites are then processed, and a subset RAIM is performed on the remaining pseudorange observations. The success of the subset RAIM is then determined. If the subset RAIM passes, it indicates that the subset SP is successful. k The pseudorange observations contain all the deceptive signals, while the remaining signals in the secondary tracking channel are all genuine signals. Therefore, PVT calculations are performed based on the remaining pseudorange observations to obtain the true navigation, positioning, and timing results. If the subset RAIM fails, then k = k + 1 is taken, and the subset SP is removed from the pseudorange observations. k The system includes pseudorange observations from the satellites. Then, subset RAIM is performed on the remaining pseudorange observations until the subset RAIM passes. Finally, PVT calculation is performed based on the remaining pseudorange observations to obtain the true navigation, positioning, and timing results. Specifically, in this embodiment, the process of performing subset RAIM on the remaining pseudorange observations is the same as performing global RAIM on the pseudorange observations, and will not be repeated here. By performing subset RAIM on the remaining pseudorange observations until the subset RAIM passes, and then performing PVT calculation based on the remaining pseudorange observations, the correct navigation, positioning, and timing results can be guaranteed to be output.
[0074] To further understand the intent of the deceiving attacker, this embodiment, after performing PVT calculation based on the pseudorange observations in step S4 to obtain the true navigation, positioning, and timing results, also includes:
[0075] S5. Calculate the pseudorange observations of all satellites in the main tracking channel;
[0076] Since most satellite signals within the main tracking channel are spoofing signals, calculating the pseudorange observations of all visible satellites within the main tracking channel is beneficial for obtaining navigation, positioning, and timing results from the spoofing signals. The process of calculating the pseudorange observations of all satellites within the main tracking channel in this embodiment is the same as step S3, and will not be repeated here.
[0077] S6. Perform global RAIM on the pseudorange observations of all satellites in the main tracking channel, and determine whether the global RAIM passes. If the global RAIM passes, perform PVT calculation based on the pseudorange observations of all satellites in the main tracking channel to obtain the navigation, positioning and timing results of the spoofing signal.
[0078] The process of performing global RAIM on pseudorange observations of all satellites in the main tracking channel in this embodiment is the same as the process of performing global RAIM on pseudorange observations in step S4, and will not be repeated here.
[0079] The test statistic is checked to see if it does not exceed the detection threshold. If it does, the global RAIM passes. When the GNSS navigation system is working normally, the pseudorange residuals are small, and the test statistic is also small. When a visible satellite malfunctions, its measured pseudorange will have a large deviation, and the test statistic will also increase, requiring fault detection. Specifically, this embodiment compares the test statistic with the detection threshold. If the test statistic is not greater than the detection threshold, it indicates that the system is not faulty, there is no real signal in the main tracking channel, and the global RAIM passes.
[0080] If the global RAIM passes, PVT calculation is performed based on the pseudorange observations of all satellites in the main tracking channel to obtain the navigation, positioning, and timing results of the spoofing signal. This embodiment uses the same technical means as existing PVT calculations for PVT calculations based on the pseudorange observations of all satellites in the main tracking channel, and will not be elaborated further here.
[0081] Furthermore, if the test statistic exceeds the detection threshold, it indicates a system fault, the presence of a real signal in the main tracking channel, and global RAIM fails. If global RAIM fails, all possible subsets of real satellites are listed. The pseudorange observations of the first subset are removed from the pseudorange observations of all satellites in the main tracking channel. Subset RAIM is then performed on the remaining pseudorange observations to determine if it passes. If it fails, the pseudorange observations of the next subset are removed from the pseudorange observations of all satellites in the main tracking channel, and subset RAIM is continued on the remaining pseudorange observations until it passes. PVT calculation is then performed based on the remaining pseudorange observations to obtain the navigation, positioning, and timing results of the spoofed signal. This embodiment lists all possible subsets of real satellites (SPs). mThe subsets are arranged in ascending order of the number of actual satellites. First, m=1 is selected, and subset SP is removed from the pseudorange observations of all satellites in the main tracking channel. m The pseudorange observations of the included satellites are then processed, and a subset RAIM is performed on the remaining pseudorange observations. The success of the subset RAIM is then determined. If the subset RAIM passes, it indicates that the subset SP is successful. m The system contains all real signals; the remaining signals in the main tracking channel are all deceptive signals. Therefore, PVT calculations are performed based on the remaining pseudorange observations to obtain the navigation, positioning, and timing results for the deceptive signals. If the subset RAIM fails, then m = m + 1 is taken, and the subset SP is removed from the pseudorange observations of all satellites in the main tracking channel. m The pseudorange observations of the included satellites are analyzed, and then a subset RAIM is performed on the remaining pseudorange observations until the subset RAIM passes. PVT calculation is then performed based on the remaining pseudorange observations to obtain the navigation, positioning, and timing results of the deception signal. Specifically, in this embodiment, the process of performing subset RAIM on the remaining pseudorange observations is the same as performing global RAIM on the pseudorange observations of all satellites in the main tracking channel, and will not be repeated here. By performing subset RAIM on the pseudorange observations of the remaining signals in the main tracking channel until the subset RAIM passes, and then performing PVT calculation based on the pseudorange observations of the remaining signals, the deception position preset by the deception attacker can be obtained, which helps to further understand the intentions of the deception attacker.
[0082] This invention provides a spoofing identification and suppression method based on dual-tracking-channel RAIM. The dual-tracking-channel receiver used in this method employs a dual-peak acquisition algorithm and uses two channels to track a single satellite. As long as the received signal still contains a real signal, the correct positioning and timing results can be maintained. At the implementation level, the dual-tracking-channel receiver essentially adds a tracking channel to the existing structure of a traditional receiver, making it relatively easy to implement.
[0083] like Figure 4 As shown, based on the above-mentioned spoofing identification and suppression method, this embodiment of the invention also provides a spoofing identification and suppression system based on dual-tracking channel RAIM, including:
[0084] The dual-peak acquisition module 1 is used to acquire the signal of each visible satellite in a dual-peak manner, and obtain the highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite.
[0085] The dual-channel tracking module 2 is used to allocate a primary tracking channel for the highest peak satellite signal and a secondary tracking channel for the second highest peak satellite signal;
[0086] The pseudorange observation calculation module 3 is used to calculate the pseudorange observations of all visible satellites in the secondary tracking channel after stable tracking.
[0087] The secondary channel RAIM test module 4 is used to perform global RAIM on pseudorange observations and determine whether the global RAIM passes. If it passes, PVT calculation is performed based on the pseudorange observations to obtain the actual navigation, positioning and timing results.
[0088] In one specific embodiment, the secondary channel RAIM test module 4 further includes:
[0089] The subset RAIM module 41 is used to enumerate all possible subsets of satellites to deceive if global RAIM fails. It removes the pseudorange observations of the satellites in the first subset from the pseudorange observations, and performs subset RAIM on the remaining pseudorange observations. It then determines whether the subset RAIM passes. If it fails, it removes the pseudorange observations of the satellites in the next subset from the pseudorange observations, and continues performing subset RAIM on the remaining pseudorange observations until subset RAIM passes. Finally, it performs PVT calculation based on the remaining pseudorange observations to obtain the true navigation, positioning, and timing results. For details, please refer to [link to relevant documentation]. Figure 5 .
[0090] In one specific embodiment, it further includes:
[0091] The main channel RAIM test module 5 is used to calculate the pseudorange observations of all satellites in the main tracking channel. It performs global RAIM on the pseudorange observations of all satellites in the main tracking channel and determines whether the global RAIM passes. If the global RAIM passes, it performs PVT calculation based on the pseudorange observations of all satellites in the main tracking channel to obtain the navigation, positioning, and timing results of the spoofing signal. For details, please refer to [link to relevant documentation]. Figure 6 .
[0092] It should be noted that each module in the aforementioned spoofing identification and suppression system based on dual-tracking channel RAIM can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of the computer device in software form, so that the processor can call and execute the corresponding operations of each module. For specific limitations regarding the spoofing identification and suppression system based on dual-tracking channel RAIM, please refer to the limitations of the spoofing identification and suppression method based on dual-tracking channel RAIM mentioned above; both have the same function and role, and will not be repeated here.
[0093] This invention also provides a terminal device, which includes:
[0094] Processor, memory, and bus;
[0095] The bus is used to connect the processor and the memory;
[0096] The memory is used to store operation instructions;
[0097] The processor is configured to execute the operation instructions by calling the operation instructions, thereby causing the processor to perform the operation corresponding to the spoofing identification and suppression method based on dual-tracking channel RAIM described above in this application.
[0098] In one alternative embodiment, a terminal device is provided, such as Figure 7 As shown, Figure 7 The terminal device 5000 shown includes a processor 5001 and a memory 5003. The processor 5001 and the memory 5003 are connected, for example, via a bus 5002. Optionally, the terminal device 5000 may also include a transceiver 5004. It should be noted that in practical applications, the transceiver 5004 is not limited to one type, and the structure of this terminal device 5000 does not constitute a limitation on the embodiments of this application.
[0099] Processor 5001 may be a CPU, a general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It may implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 5001 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.
[0100] Bus 5002 may include a path for transmitting information between the aforementioned components. Bus 5002 may be a PCI bus or an EISA bus, etc. Bus 5002 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.
[0101] The memory 5003 may be a ROM or other type of static storage device capable of storing static information and instructions, RAM or other type of dynamic storage device capable of storing information and instructions, or it may be an EEPROM, CD-ROM or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto.
[0102] The memory 5003 is used to store application code that executes the scheme of this application, and its execution is controlled by the processor 5001. The processor 5001 is used to execute the application code stored in the memory 5003 to implement the content shown in any of the foregoing method embodiments.
[0103] Among them, terminal equipment refers to navigation receivers.
[0104] In summary, this invention provides a spoofing identification and suppression method, system, and device based on dual-tracking-channel RAIM. The dual-tracking-channel receiver employs a dual-peak acquisition algorithm and uses two channels to track a single satellite. As long as the received signal still contains a real signal, the correct positioning and timing results can be maintained. At the implementation level, the dual-tracking-channel receiver essentially adds a tracking channel to the existing structure of a traditional receiver, making it relatively easy to implement.
[0105] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the embodiments, refer to each other. Each embodiment focuses on its differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.
[0106] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.
Claims
1. A spoofing detection and suppression method based on dual-tracking channel RAIM, characterized in that, include: The signal from each visible satellite is captured using a dual-peak acquisition method to obtain the highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite. A primary tracking channel is allocated to the highest peak satellite signal, and a secondary tracking channel is allocated to the second highest peak satellite signal; After stable tracking, calculate the pseudorange observations of all visible satellites in the secondary tracking channel; Global RAIM is performed on the pseudorange observations. If the global RAIM passes, PVT calculation is performed based on the pseudorange observations to obtain the true navigation, positioning, and timing results. If the global RAIM fails, all possible subsets of spoofed satellites are listed. The pseudorange observations of the satellites in the first subset are removed from the pseudorange observations. Subset RAIM is then performed on the remaining pseudorange observations. If the subset RAIM fails, the pseudorange observations of the satellites in the next subset are removed from the pseudorange observations. The subset RAIM is then performed on the remaining pseudorange observations until the subset RAIM passes. PVT calculation is then performed based on the remaining pseudorange observations to obtain the true navigation, positioning, and timing results. The process of performing bimodal acquisition on the signal of each visible satellite to obtain the highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite includes: The signal of each visible satellite is searched from three dimensions: PRN code, pseudo-code phase, and carrier Doppler frequency shift. Satellite signals that achieve the maximum value and exceed the acquisition threshold in the two-dimensional correlation result of pseudo-code phase-carrier Doppler frequency shift, and satellite signals that achieve the second maximum value and exceed the acquisition threshold are captured. The highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite are obtained respectively.
2. The deception identification and suppression method according to claim 1, characterized in that, The global RAIM process for the pseudorange observations includes: Based on the pseudorange observations, the receiver position estimate is obtained using the least squares method. Based on the pseudorange observations and the receiver position estimate, the pseudorange residual is obtained; The test statistic for the sum of squares of the pseudo-range residuals is obtained based on the pseudo-range residuals. Determine whether the test statistic does not exceed the detection threshold. If it does not, the global RAIM passes.
3. The deception identification and suppression method according to claim 1, characterized in that, After performing PVT calculation based on the pseudorange observations to obtain the actual navigation, positioning, and timing results, the method further includes: Calculate the pseudorange observations for all satellites within the main tracking channel; Global RAIM is performed on the pseudorange observations of all satellites in the main tracking channel. It is then determined whether the global RAIM passes. If the global RAIM passes, PVT is performed based on the pseudorange observations of all satellites in the main tracking channel to obtain the navigation, positioning, and timing results of the spoofing signal.
4. The deception identification and suppression method according to claim 3, characterized in that, The determination of whether the global RAIM passes also includes: If global RAIM fails, then all possible subsets of real satellites are listed. The pseudorange observations of the first subset are removed from the pseudorange observations of all satellites in the main tracking channel. Subset RAIM is then performed on the remaining pseudorange observations. If the subset RAIM fails, the pseudorange observations of the next subset are removed from the pseudorange observations of all satellites in the main tracking channel. This process of performing subset RAIM on the remaining pseudorange observations continues until the subset RAIM passes. PVT is then performed based on the remaining pseudorange observations to obtain the navigation, positioning, and timing results for the spoofed signal.
5. A spoofing detection and suppression system based on dual-tracking-channel RAIM, characterized in that, include: The dual-peak acquisition module is used to acquire the signal of each visible satellite in a dual-peak manner, obtaining the highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite; A dual-channel tracking module is used to allocate a primary tracking channel for the highest peak satellite signal and a secondary tracking channel for the second highest peak satellite signal; The pseudorange observation calculation module is used to calculate the pseudorange observations of all visible satellites in the secondary tracking channel after stable tracking. The secondary channel RAIM test module is used to perform global RAIM on the pseudorange observations, determine whether the global RAIM passes, and if it passes, perform PVT calculation based on the pseudorange observations to obtain the actual navigation, positioning and timing results. The secondary channel RAIM test module also includes: The subset RAIM module is used to enumerate all possible subsets of satellites to deceive if global RAIM fails. It then removes the pseudorange observations of the satellites in the first subset from the pseudorange observations, performs subset RAIM on the remaining pseudorange observations, and determines whether the subset RAIM passes. If it fails, it removes the pseudorange observations of the satellites in the next subset from the pseudorange observations, and continues performing subset RAIM on the remaining pseudorange observations until the subset RAIM passes. Finally, it performs PVT calculation based on the remaining pseudorange observations to obtain the true navigation, positioning, and timing results. The process of performing bimodal acquisition on the signal of each visible satellite to obtain the highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite includes: The signal of each visible satellite is searched from three dimensions: PRN code, pseudo-code phase, and carrier Doppler frequency shift. Satellite signals that achieve the maximum value and exceed the acquisition threshold in the two-dimensional correlation result of pseudo-code phase-carrier Doppler frequency shift, and satellite signals that achieve the second maximum value and exceed the acquisition threshold are captured. The highest peak satellite signal and the second highest peak satellite signal of the captured visible satellite are obtained respectively.
6. The deception detection and suppression system according to claim 5, characterized in that, Also includes: The main channel RAIM test module is used to calculate the pseudorange observations of all satellites in the main tracking channel, perform global RAIM on the pseudorange observations of all satellites in the main tracking channel, and determine whether the global RAIM passes. If the global RAIM passes, PVT calculation is performed based on the pseudorange observations of all satellites in the main tracking channel to obtain the navigation, positioning, and timing results of the spoofing signal.
7. A terminal device, characterized in that, The method includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements the spoofing identification and suppression method as described in any one of claims 1 to 4.