Method for carrying out deception detection on satellite, receiver and medium
By performing observation consistency detection of GNSS signals received in the satellite navigation system, the problem of high risk of receiver spoofing in loose mode is solved, reducing hardware costs and improving positioning accuracy.
Patent Information
- Application Number
- CN202411918784.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2025-03-21
AI Technical Summary
In the loose mode of the satellite navigation system, the risk of fraud of the receiver is high, and the development of navigation message certification for the entire system is not sufficient, resulting in an increase in hardware costs.
By processing the received GNSS signal, the observation values and navigation messages of the visual satellite are determined, and the observation values consistency detection is performed on the first satellite that supports navigation messages authentication and the second satellite that does not support authentication, and the fraud detection results of the second satellite are output to represent their credibility.
Reduces the risk of spoofing in loose mode, reduces computing and memory overhead, reduces hardware costs, and improves non-safety performance such as positioning accuracy.
Smart Images
Figure CN119667717A_ABST
Abstract
Description
Technical Field
[0001] This article relates to the field of navigation and positioning technology, and in particular to a method, receiver and medium for detecting satellite deception. Background Art
[0002] In recent years, the navigation message authentication technology applied to satellites has made significant progress. The receivers in the Global Navigation Satellite System (GNSS) authenticate satellites through navigation messages, which can ensure the authenticity and integrity of the received navigation messages, thereby effectively combating spoofing attacks and significantly improving the security of the receivers.
[0003] For example, the Galileo system's Open Service Navigation Message Authentication (OSNMA) can provide users with two types of services: tight mode and loose mode. In tight mode, only certified satellites are used for PVT (Position Velocity Time) solution, which can effectively ensure the security of the system, but may lose performance other than security, such as positioning accuracy and availability. In loose mode, PVT solution is performed using both certified and uncertified satellites, which can effectively ensure non-security performance such as positioning accuracy and availability, but the system's anti-spoofing ability is weakened.
[0004] With the promotion and application of navigation message authentication function of other navigation systems (such as Beidou navigation system), the navigation message authentication of the whole system can alleviate the degradation of the non-safety performance of the receiver in tight mode, but the increase in computing and memory overhead will increase the hardware cost of the receiver. In addition, due to the insufficient development of the navigation message authentication of the whole system and the application scenarios that prioritize non-safety performance, loose mode is a more reasonable choice, but the risk of deception in loose mode is higher.
[0005] Therefore, how to reduce the risk of receiver deception in loose mode of satellite navigation system and improve non-safety performance such as positioning accuracy while ensuring safety is an issue worthy of attention. Summary of the invention
[0006] Embodiments of the present application provide a method, a receiver, and a medium for detecting satellite spoofing.
[0007] In a first aspect, an embodiment of the present application provides a method for detecting spoofing on satellites, the method comprising: determining observation values and navigation messages of currently visible satellites based on received GNSS signals; authenticating satellites that support navigation message authentication among currently visible satellites, and using the authenticated satellites as first satellites, and using satellites that do not support navigation message authentication as second satellites; in the presence of a first satellite, performing observation value consistency spoofing detection on the second satellite based on the observation values of the first satellite and the observation values of the second satellite, and outputting a spoofing detection result of the second satellite, wherein the spoofing detection result is used to characterize the credibility of the second satellite.
[0008] In a second aspect, an embodiment of the present application provides a receiver for use in a satellite navigation system, the receiver being configured to: receive GNSS signals sent by satellites in the satellite navigation system; and based on the received GNSS signals, perform spoofing detection on visible satellites by using the method for satellite spoofing detection in the above embodiment.
[0009] In a third aspect, an embodiment of the present application provides a non-volatile computer storage medium, which stores a computer program. When the computer program is executed by a processor, the method for detecting satellite deception in the above embodiment is implemented.
[0010] The method for satellite deception detection in the embodiment of the present application can use the observation value of the first satellite that has passed the navigation message authentication to perform observation value consistency deception detection on the second satellite that has not passed the navigation message authentication, which can reduce the deception risk of the receiver in loose mode and has low computing and memory overhead, which is beneficial to reducing the hardware cost of the receiver.
[0011] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.
[0013] Figure 1 A flowchart of an embodiment of a method for detecting satellite deception according to the present application; Figure 2 A flowchart of another embodiment of the method for detecting satellite deception according to the present application; Figure 3A schematic diagram of a flow chart of consistency detection of a first type of observation value in one embodiment of a method for detecting satellite deception in the present application; Figure 4 A schematic diagram of a flow chart of consistency detection of the second type of observation values in one embodiment of the method for detecting satellite deception in the present application; Figure 5 A schematic diagram of a flow chart for determining a valid PVT solution result in one embodiment of a method for detecting satellite spoofing according to the present application. DETAILED DESCRIPTION
[0014] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.
[0015] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.
[0016] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.
[0017] Figure 1A flowchart of an embodiment of a method for detecting satellite deception according to the present application is shown as follows: Figure 1 As shown, the process may include the following steps.
[0018] Step 110: Determine the observation values and navigation messages of currently visible satellites based on the received GNSS signals.
[0019] In this embodiment, the currently visible satellite refers to the satellite from which the receiver can receive GNSS (Global Navigation Satellite System) signals at the current moment. The receiver can perform baseband signal processing such as sampling, capturing, tracking, and decoding on the received GNSS signals to obtain baseband information such as observation values of the visible satellite at each frequency point and navigation messages.
[0020] As examples, observations may include receiver time, pseudorange and Doppler observations, multipath effects, signal strength, etc.
[0021] Step 120: Authenticate the satellites that support navigation message authentication among the currently visible satellites to determine whether there is a first satellite that has passed the authentication.
[0022] In this embodiment, the receiver classifies the visible satellites according to whether they support navigation message authentication, and uses the satellites that do not support navigation message authentication as the second satellites, performs navigation message authentication on the satellites that support navigation message authentication (such as satellites at the E1 frequency of the Galileo system), and then uses the satellites that have passed the navigation message authentication as the first satellite.
[0023] In the absence of the first satellite, the spoofing detection result is directly output.
[0024] Step 130: In the case where the first satellite exists, a satellite that does not support navigation message authentication is used as a second satellite, and based on the observation values of the first satellite and the observation values of the second satellite, an observation value consistency spoofing detection is performed on the second satellite, and the spoofing detection result of the second satellite is output.
[0025] The deception detection result is used to characterize the credibility of the second satellite.
[0026] In this embodiment, the spoofing detection result may include whether the second satellite passes the spoofing detection and a corresponding credibility rating. For example, the credibility of a second satellite that passes the spoofing detection is higher than that of a second satellite that fails the spoofing detection or does not undergo spoofing detection.
[0027] For the same receiver, some types of observation values obtained based on signals from different satellites are consistent, such as receiver time observation values. The specific type of observation value of the first satellite can be compared with the corresponding observation value of the second satellite. If the two are consistent (i.e., the difference is small), it is determined that the second satellite has passed the deception detection; if the two are inconsistent (i.e., the difference is large), it is determined that the second satellite has not passed the deception detection.
[0028] In this embodiment, the first satellite authenticated by the navigation message is a prerequisite for performing observation consistency spoofing detection on the second satellite. If the first satellite does not exist, the detection can be terminated. At this time, the second satellite can be marked as not subjected to spoofing detection in the spoofing detection result.
[0029] The method for satellite deception detection in the embodiment of the present application can use the observation value of the first satellite that has passed the navigation message authentication to perform observation value consistency deception detection on the second satellite that has not passed the navigation message authentication, which can reduce the deception risk of the receiver in loose mode and has low computing and memory overhead, which is beneficial to reducing the hardware cost of the receiver.
[0030] Figure 2 A flowchart showing an embodiment of a method for detecting satellite deception according to the application is shown. Figure 2 In the illustrated embodiment, the observation values of the first satellite and the observation values of the second satellite both include multiple types of observation values, such as receiver time observation values, pseudorange observation values, and Doppler observation values. Figure 2 As shown, the process may include the following steps.
[0031] Step 210: Determine the observation values and navigation messages of currently visible satellites based on the received GNSS signals.
[0032] Step 220: Authenticate the satellites that support navigation message authentication among the currently visible satellites to determine whether there is a first satellite that has passed the authentication.
[0033] When the first satellite does not exist, the spoofing detection result is directly output; when the first satellite exists, a satellite that does not support navigation message authentication is used as the second satellite, and steps 230 to 250 are executed.
[0034] Step 230: Use a satellite that does not support navigation message authentication as a second satellite, and perform consistency detection of the first type of observation value on the second satellite based on the first type of observation value of the first satellite and the first type of observation value of the second satellite.
[0035] Step 240: If the second satellite fails the consistency check of the first type of observations, determine that the second satellite fails the spoofing check.
[0036] Step 250: When the second satellite passes the consistency check of the first type of observations, perform a consistency check of the second type of observations on the second satellite based on the second type of observations of the first satellite and the second type of observations of the second satellite.
[0037] Step 260: When the second satellite passes the consistency detection of the second type of observations, determine that the second satellite passes the spoofing detection.
[0038] Step 270: If the second satellite fails the consistency check of the second type of observations, determine that the second satellite fails the spoofing check.
[0039] In this embodiment, the first type of observation and the second type of observation are different types of observations. Based on the two types of observations, two consistency deception detections are performed on the second satellite, and the results of the two deception detections are summarized to generate a deception detection result. As an example, the deception detection result may include the number of times the second satellite passes the consistency detection and the credibility rating, the second satellite that passes the consistency detection of the second type of observation has the highest credibility, the second satellite that only passes the consistency detection of the first type of observation has the second highest credibility, and the second satellite that fails to pass the first type of observation has the lowest credibility.
[0040] In this embodiment, multiple consistency spoofing detections are performed on the second satellite based on multiple types of observation values, which can further improve the reliability of spoofing detection.
[0041] Next reference Figure 3 ,exist Figure 3 In the embodiment shown, the first type of observation is a receiver time observation, such as Figure 3 As shown, the above step 230 may include the following steps.
[0042] Step 310: Determine a reference observation value of the receiver time based on the receiver time observation value of the first satellite.
[0043] As an example, the following parameters of the receiver receiving any satellite can be obtained from the baseband information obtained in step 110: the second of the week of the current frame 、Number of integer bits of the message received in the current frame , message code phase , the transmission rate of the message and the propagation delay of the satellite's average orbital altitude Based on the acquired parameters, the receiver time observation value of the first satellite can be calculated by the following formula (1): : (1) Executing the above steps for each first satellite can determine the receiver observation value of each first satellite, and then taking the average of the receiver observation values of multiple first satellites as the reference observation value.
[0044] In this embodiment, the accuracy of the receiver time observation value can be seconds, milliseconds or others. It can be understood that the higher the accuracy, the higher the reliability of consistency detection, but the corresponding computing hardware requirements and costs are also higher. The accuracy of the receiver observation value can be set according to actual needs to take into account both reliability and cost. For example, it can be set to milliseconds.
[0045] Step 320: Determine a first difference between the receiver time observation value of the second satellite and the reference observation value.
[0046] Based on the above formula (1), the receiver time observation value of each second satellite can be determined, and the difference between the time observation value and the reference observation value can be used to determine the first difference value corresponding to each second satellite.
[0047] Step 330: When the first difference is greater than a preset first threshold, determine that the second satellite fails the consistency detection of the first type of observations.
[0048] Step 340: When the first difference is not greater than the first threshold, determine that the second satellite passes the consistency detection of the first type of observations.
[0049] In this embodiment, the reference observation value can represent the receiver time observation value corresponding to all the first satellites. If the first difference value corresponding to the second satellite is greater than the first threshold, it means that the receiver time observation value of the second satellite is inconsistent with the receiver time observation value corresponding to all the first satellites, and the second satellite fails to pass the consistency detection of the first type of observation value; conversely, if the first difference value corresponding to the second satellite is not greater than the first threshold, it means that the receiver time observation value of the second satellite is consistent with the receiver time observation value corresponding to all the first satellites, and the second satellite passes the consistency detection of the first type of observation value.
[0050] exist Figure 3 In the illustrated embodiment, the receiver time observation value may be used as a first type of observation value, and a reference observation value may be determined based on the receiver time observation value of the first satellite. By comparing the receiver time observation value of the second satellite with the reference observation value, it may be determined whether the receiver time observation value of the second satellite is consistent with that of the first satellite. This may more accurately and efficiently determine whether the second satellite passes the consistency test of the first type of observation value.
[0051] Reference below Figure 4 ,exist Figure 4 In the embodiment shown, the second type of observations are pseudorange observations and Doppler observations. Figure 4 As shown, the above step 250 may include the following steps.
[0052] Step 410: When the sum of the number of first satellites and the number of second satellites that pass the consistency check of the first type of observations is less than the minimum number of satellites required for PVT solution, determine that the second satellite fails the consistency check of the second type of observations.
[0053] Step 420: When the sum of the number of first satellites and the number of second satellites that pass the consistency check of the first type of observations is not less than the minimum number of satellites required for PVT solution, perform PVT solution and determine whether there is a valid PVT solution result.
[0054] In this embodiment, a valid PVT (Position Velocity Time) solution result refers to a PVT solution result that is verified to be credible. As an example, the pseudorange and Doppler observation value of the first satellite can be predicted based on the PVT solution result of the first satellite, and then the predicted value is compared with the pseudorange and Doppler observation value (also called tracking pseudorange and Doppler observation value) obtained in step 110. If the two are consistent, the PVT solution is valid, that is, the PVT solution result is credible; if the two are inconsistent, the PVT solution result is invalid, that is, it is not credible.
[0055] Step 430: In the absence of a valid PVT solution result, determine that the second satellite fails the consistency check of the second type of observations.
[0056] Step 440: When there is a valid PVT solution result, determine the pseudorange prediction value and Doppler prediction value corresponding to the second satellite at each frequency point based on the valid PVT solution result and the ephemeris of the second satellite.
[0057] In this embodiment, the pseudorange prediction value and the Doppler prediction value represent the pseudorange and Doppler values calculated based on the effective PVT solution results. In contrast, the pseudorange observation value and the Doppler observation value (also referred to as the tracking pseudorange observation value and the tracking Doppler observation value) are obtained through the GNSS signal in step 110.
[0058] As an example, according to the ephemeris of the second satellite S at any frequency point, the satellite position of the second satellite S at the frequency point is determined. 、Satellite clock error , ionospheric delay and tropospheric delay , assuming that the PVT result of receiver R includes the receiver position and receiver clock difference The pseudorange prediction value of the second satellite S can be determined by the following formula (2): .
[0059] According to the ephemeris of the second satellite S at any frequency point, the satellite speed of the second satellite S at the frequency point is determined and satellite clock drift , assuming that the PVT result of receiver R includes the receiver speed and receiver clock drift The pseudorange and Doppler prediction value of the second satellite S can be determined by the following formula (3): .
[0060] (3) Step 450: Determine a second difference between the pseudorange prediction value corresponding to each frequency point of the second satellite and the acquired pseudorange observation value, and a third difference between the Doppler prediction value and the acquired Doppler observation value.
[0061] Step 460: Determine whether each frequency point of the second satellite meets the first preset condition.
[0062] The first preset condition includes: the second difference corresponding to the frequency point is not greater than a preset second threshold and the third difference is not greater than a preset third threshold.
[0063] Step 470: When all frequency points of the second satellite do not satisfy the first preset condition, determine that the second satellite fails to pass the consistency detection of the second type of observation values.
[0064] In this embodiment, the pseudorange and Doppler prediction values obtained by the effective PVT solution result can represent the expectation of the pseudorange observation value and Doppler observation value obtained according to the credible information. By comparing the pseudorange prediction value and the Doppler prediction value with the acquired pseudorange observation value and the Doppler observation value, the consistency detection of the second type of observation value can be performed on each frequency point of the second satellite. The consistency degree between the pseudorange prediction value and the pseudorange observation value is characterized by the second difference value, and the consistency degree between the Doppler prediction value and the Doppler observation value is characterized by the third difference value. All the frequency points of the second satellite do not meet the first preset condition, indicating that the second type of observation value of each frequency point of the second satellite is inconsistent with the expectation, and it is determined that the second satellite has not passed the consistency detection of the second type of observation value, that is, each frequency point of the second satellite is not credible or has low credibility, which helps to improve the reliability of deception detection.
[0065] In some optional implementations of this embodiment, when there is a frequency point that meets the first preset condition among the multiple frequency points of the second satellite, Figure 4 The illustrated embodiment may also include steps 480 to 496 .
[0066] Step 480: Select a frequency point that meets the first preset condition as a reference frequency point.
[0067] As an example, any frequency point may be selected from various frequency points that meet the first preset condition as a reference frequency point.
[0068] Step 490: Determine a fourth difference between the pseudorange observation values corresponding to other frequency points of the second satellite and the pseudorange prediction value of the reference frequency point, and a fifth difference between the Doppler observation values corresponding to other frequency points and the Doppler observation value of the reference frequency point.
[0069] As an example, the second satellite may include frequency point 1, frequency point 2, frequency point 3 and frequency point 4, wherein, through step 450, it can be determined that frequency point 4 does not meet the first preset condition, and then one of frequency point 1, frequency point 2 and frequency point 3 can be selected as the reference frequency point, for example, frequency point 1. The pseudorange observation values and Doppler observation values corresponding to each of frequency point 1, frequency point 2 and frequency point 3 can be determined from the observation values obtained in the above step 110, and then the differences between the pseudorange observation values and Doppler observation values corresponding to frequency point 2 and frequency point 3 and the pseudorange observation value and Doppler observation value corresponding to frequency point 1 are determined, respectively, to obtain the fourth difference value and the fifth difference value corresponding to frequency point 2 and frequency point 3, respectively.
[0070] Step 492: For any frequency point of the second satellite, if the frequency point meets the second preset condition, determine that the frequency point passes the spoofing detection.
[0071] Step 494: When the frequency point does not meet the second preset condition, determine that the frequency point has not passed the spoofing detection.
[0072] The second preset condition includes that the fourth difference corresponding to the frequency point is not greater than a preset fourth threshold and the fifth difference is not greater than a preset fifth threshold.
[0073] In this embodiment, the second preset condition can characterize the consistency of pseudorange observation values and Doppler observation values between different frequency points of the same second satellite, so as to perform deception detection on each frequency point of the same second satellite, which helps to further expand the coverage of deception detection.
[0074] Step 496: Record the detection results of each frequency point of the second satellite in the deception detection result.
[0075] As an example, for a second satellite that fails the consistency test for the first type of observation values and a second satellite that fails the consistency test for the second type of observation values, all frequency points of the second satellite fail the spoofing detection; for a second satellite that passes the consistency test for the first type of observation values and has frequency points that meet the second preset condition, the frequency points that meet the second preset condition can be marked as passing the spoofing detection, and the frequency points that do not meet the second preset condition can be marked as failing the spoofing detection.
[0076] In this embodiment, the deception detection result may include whether each frequency point in the second satellite passes the deception detection, so as to detect the credibility of each frequency point in the satellite, which can refine the granularity of the satellite's deception detection and help improve the utilization rate of the satellite.
[0077] In some embodiments, the above step 420 may include Figure 5 The process shown is as follows Figure 5 As shown, the process may include the following steps.
[0078] Step 510: When the number of the first satellites is not less than the minimum number of satellites required for the PVT solution, perform the PVT solution based on the first satellites, and confirm the obtained PVT solution result as a valid PVT solution result.
[0079] Step 520: When the number of first satellites is less than the minimum number of satellites required for PVT solution, select candidate satellites from the second satellites that pass the consistency detection of the first type of observations, so that the sum of the number of first satellites and the number of candidate satellites is not less than the minimum number of satellites required for PVT solution.
[0080] Step 530: Perform PVT solution based on the first satellite and the candidate satellites to obtain a pending PVT solution result.
[0081] Step 540: Determine a pseudorange prediction value and a Doppler prediction value of each first satellite based on the pending PVT solution result and the ephemeris of each first satellite.
[0082] Step 550: Determine a sixth difference between the pseudorange prediction value and the acquired pseudorange observation value of each first satellite and a seventh difference between the Doppler prediction value and the acquired Doppler observation value.
[0083] Step 560: When all first satellites satisfy the third preset condition, determine that the pending PVT solution result is a valid PVT solution result.
[0084] The third preset condition includes: the sixth difference corresponding to the first satellite is not greater than a preset sixth threshold and the seventh difference is not greater than a preset seventh threshold.
[0085] In this embodiment, the validity of the PVT solution result can be verified by whether the pseudorange prediction value and Doppler prediction value of the first satellite are consistent with the pseudorange observation value and Doppler observation value, so as to ensure that the valid PVT solution result is obtained based on reliable information, so as to be used for consistency detection of the pseudorange and Doppler observation values of the second satellite.
[0086] In some optional implementations of this embodiment, when the sum of the number of first satellites and the number of second satellites detected by the consistency check of the first type of observations is not less than the minimum number of satellites required for PVT solution, Figure 5 The illustrated embodiment may further include the following steps 570 and 580 .
[0087] Step 570: When any first satellite does not satisfy the third preset condition, determine that the pending PVT solution result is an invalid PVT solution result, reselect a candidate satellite from the second satellites that have passed the consistency test of the first type of observations, and perform PVT solution based on the reselected candidate satellite and the first satellite to obtain a new PVT solution result.
[0088] Step 580: re-determine whether each first satellite meets the third preset condition based on the new PVT solution result to determine whether the new PVT solution result is a valid PVT solution result, until the preset termination condition is met.
[0089] The termination conditions include: the number of PVT solutions reaches a preset number; or the new PVT solution result is a valid PVT solution result.
[0090] In this implementation, the preset number of times may be set in advance according to the computing capability of the receiver.
[0091] In a specific example, it is assumed that the first satellite includes satellite A and satellite B, and the second satellite includes satellite a, satellite b, and satellite C. If the minimum number of satellites required for PVT solution is 2, PVT solution can be performed based on satellite A and satellite B to obtain a valid PVT solution result.
[0092] If the minimum number of satellites required for PVT solution is 4, then 2 second satellites need to be selected for supplementation. At this time, multiple groups of second satellites for supplementation can be determined by permutation and combination, for example, they may include: satellite a and satellite b, satellite a and satellite c, satellite b and satellite c. For example, PVT solution can be performed based on satellite A, satellite B, satellite a and satellite b to obtain a pending PVT solution result. Then, the pending PVT solution result is verified through steps 540 and 550. If all the first satellites meet the third preset condition, the pending PVT solution result is determined to be a valid PVT solution result; if any of the first satellites does not meet the third preset condition, the pending PVT solution result is determined to be an invalid PVT solution result.
[0093] Afterwards, satellite a and satellite b can be replaced by satellite a and satellite c, and then combined with satellite A and satellite C to perform PVT solution to obtain a new PVT solution result, and repeat the above steps 540 and 550 to verify the new PVT solution result. If the new PVT solution result is a valid PVT solution result, the iteration is terminated and the above steps 430 to 490 are executed. If the new PVT solution result is still an invalid PVT solution result, the second satellite is replaced again and the above steps are repeated.
[0094] When the number of PVT solution times reaches a preset number, the iteration ends. If no valid PVT solution result is determined, it is determined according to step 410 that all second satellites fail the consistency test of the second type of observations.
[0095] In this embodiment, the second satellite is selected by permutation and combination so as to perform PVT solution in combination with the first satellite, and whether there is a valid PVT solution result is determined by iteration.
[0096] In some embodiments, when the number of first satellites is not less than the minimum number of satellites required for PVT solution, the consistency check of other types of observations (e.g., first type of observations) can be omitted, and the consistency check of the pseudorange observations and Doppler observations of the second satellite is performed based on the pseudorange observations and Doppler observations of the first satellite and the pseudorange observations and Doppler observations of the second satellite.
[0097] Here, the consistency check of pseudorange and Doppler observation value of the second satellite can be carried out by using the above method. Figure 4 and Figure 5 The process shown will not be repeated here.
[0098] In this embodiment, when the number of first satellites is not less than the minimum number of satellites required for PVT solution, the consistency check of other types of observation values (such as the first type of observation values) can be omitted, and the consistency check of pseudorange and Doppler observation values can be directly performed. Under the premise of ensuring the reliability of deception detection, the detection steps can be reduced, which helps to reduce the computational complexity of deception detection and improve the efficiency of deception detection.
[0099] In some embodiments, after outputting the spoofing detection result of the second satellite, the spoofing result can be applied to positioning solution. For example, it may include: when the number of first satellites does not meet the number of satellites required for positioning solution, based on the spoofing detection result, selecting a second satellite with high credibility and / or a frequency point with high credibility to supplement, so as to perform positioning solution, and outputting the credibility of the positioning solution result.
[0100] In this embodiment, highly credible satellites and / or highly credible frequencies are selected for positioning solution based on the deception detection results, which can reduce the security risks caused by fraudulent satellites and improve non-safety performance such as receiver positioning accuracy, thereby improving the overall performance of the receiver in loose mode.
[0101] An embodiment of the present application provides a receiver for use in a satellite navigation system, wherein the receiver is configured to: receive GNSS signals sent by satellites in the satellite navigation system; and based on the received GNSS signals, perform spoofing detection on visible satellites using the method for performing spoofing detection on satellites in the above embodiment.
[0102] An embodiment of the present application provides a satellite navigation system, including a satellite and the receiver in the above embodiment.
[0103] An embodiment of the present application also provides a non-transitory computer storage medium, which stores a computer program. In some embodiments, when the computer program is executed by a processor, the method for detecting satellite deception in any of the above embodiments is implemented.
[0104] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or transient medium). As is known to those skilled in the art, the term "computer storage medium" includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.
Claims
1. A method for detecting satellite deception, characterized in that: The method comprises: Based on the received GNSS signals, determine the observation values and navigation messages of the currently visible satellites; Authenticating satellites that support navigation message authentication among the currently visible satellites, and determining whether there is a first satellite that passes the authentication; In the case where the first satellite exists, a satellite that does not support navigation message authentication is used as a second satellite, and based on the observation values of the first satellite and the observation values of the second satellite, an observation value consistency deception detection is performed on the second satellite, and a deception detection result of the second satellite is output, and the deception detection result is used to characterize the credibility of the second satellite.
2. The method according to claim 1, characterized in that The observation value of the first satellite and the observation value of the second satellite each include observation values of multiple types; as well as, Performing observation consistency deception detection on the second satellite, comprising: performing consistency detection of the first type of observations on the second satellite based on the first type of observations of the first satellite and the first type of observations of the second satellite; In the event that the second satellite fails the consistency detection of the first type of observations, it is determined that the second satellite fails the spoofing detection.
3. The method according to claim 2, characterized in that Performing observation consistency deception detection on the second satellite also includes: When the second satellite passes the consistency check of the first type of observations, performing a consistency check of the second type of observations on the second satellite based on the second type of observations of the first satellite and the second type of observations of the second satellite; In a case where the second satellite passes the consistency detection of the second type of observations, determining that the second satellite passes the spoofing detection; In the event that the second satellite fails the consistency detection of the second type of observations, it is determined that the second satellite fails the spoofing detection.
4. The method according to claim 2, characterized in that: The first type of observation value is a receiver time observation value; as well as, Based on the first type of observation value of the first satellite and the first type of observation value of the second satellite, a consistency check of the first type of observation value is performed on the second satellite, including: determining a reference observation value of the receiver time based on the receiver time observation value of the first satellite; determining a first difference between the receiver time observation value of the second satellite and the reference observation value; when the first difference is greater than a preset first threshold, determining that the second satellite has failed the consistency check of the first type of observation value; when the first difference is not greater than the first threshold, determining that the second satellite has passed the consistency check of the first type of observation value.
5. The method according to claim 2, characterized in that: The second type of observations are pseudorange observations and Doppler observations; Based on the second type of observation value of the first satellite and the second type of observation value of the second satellite, performing consistency detection of the second type of observation value on the second satellite includes: When the sum of the number of the first satellites and the number of the second satellites that pass the consistency check of the first type of observations is less than the minimum number of satellites required for PVT solution, determining that the second satellite fails the consistency check of the second type of observations; When the sum of the number of the first satellites and the number of the second satellites detected by the consistency check of the first type of observations is not less than the minimum number of satellites required for PVT solution, perform PVT solution and determine whether there is a valid PVT solution result; In the absence of the valid PVT solution result, determining that the second satellite fails the consistency detection of the second type of observations; In the case where the valid PVT solution result exists, determining a pseudorange prediction value and a Doppler prediction value corresponding to each frequency point of the second satellite based on the valid PVT solution result and the ephemeris of the second satellite; Determine a second difference between a pseudorange prediction value corresponding to each frequency point of the second satellite and the acquired pseudorange observation value and a third difference between a Doppler prediction value and the acquired Doppler observation value; Determine whether each frequency point of the second satellite meets a first preset condition, where the first preset condition includes: a second difference value corresponding to the frequency point is not greater than a preset second threshold value and a third difference value is not greater than a preset third threshold value; When all frequency points of the second satellite do not satisfy the first preset condition, it is determined that the second satellite fails the consistency detection of the second type of observation values.
6. The method according to claim 5, characterized in that Based on the second type of observation value of the first satellite and the second type of observation value of the second satellite, performing consistency detection of the second type of observation value on the second satellite further includes: When there is a frequency point satisfying the first preset condition among the multiple frequency points of the second satellite, selecting a frequency point satisfying the first preset condition as a reference frequency point; Determine a fourth difference between pseudorange observation values corresponding to other frequency points of the second satellite and the pseudorange prediction value of the reference frequency point, and a fifth difference between Doppler observation values corresponding to other frequency points and the Doppler observation value of the reference frequency point; For any frequency point of the second satellite, if the frequency point meets the second preset condition, it is determined that the frequency point passes the spoofing detection; if the frequency point does not meet the second preset condition, it is determined that the frequency point does not pass the spoofing detection; the second preset condition includes that the fourth difference corresponding to the frequency point is not greater than the preset fourth threshold value and the fifth difference is not greater than the preset fifth threshold value; The detection results of each frequency point of the second satellite are recorded in the spoofing detection result.
7. The method according to claim 5, characterized in that When the sum of the number of the first satellites and the number of the second satellites that pass the consistency detection of the first type of observations is not less than the minimum number of satellites required for PVT solution, performing PVT solution and determining whether there is a valid PVT solution result includes: When the number of the first satellites is not less than the minimum number of satellites required for PVT solution, performing PVT solution based on the first satellites, and confirming the obtained PVT solution result as the valid PVT solution result; When the number of the first satellites is less than the minimum number of satellites required for PVT solution, selecting candidate satellites from second satellites that pass the consistency detection of the first type of observations, so that the sum of the number of the first satellites and the number of the candidate satellites is not less than the minimum number of satellites required for PVT solution; Performing PVT solution based on the first satellite and the candidate satellite to obtain a pending PVT solution result; Determine a pseudorange prediction value and a Doppler prediction value of each of the first satellites based on the pending PVT solution result and the ephemeris of each of the first satellites; Determine a sixth difference between a predicted pseudorange value and an acquired pseudorange observation value and a seventh difference between a predicted Doppler value and an acquired Doppler observation value of each of the first satellites; When all of the first satellites satisfy the third preset condition, the pending PVT solution result is determined to be the valid PVT solution result; the third preset condition includes that the sixth difference corresponding to the first satellite is not greater than the preset sixth threshold and the seventh difference is not greater than the preset seventh threshold.
8. The method according to claim 7, characterized in that When the sum of the number of the first satellites and the number of the second satellites that pass the consistency detection of the first type of observations is not less than the minimum number of satellites required for PVT solution, performing PVT solution and determining whether there is a valid PVT solution result, further comprising: In the case that any of the first satellites does not satisfy the third preset condition, determining that the pending PVT solution result is an invalid PVT solution result, reselecting a candidate satellite from the second satellites that pass the consistency detection of the first type of observations, and performing PVT solution based on the reselected candidate satellite and the first satellite to obtain a new PVT solution result; Based on the new PVT solution result, it is re-determined whether each of the first satellites meets the third preset condition to determine whether the new PVT solution result is the valid PVT solution result, until a preset termination condition is met, and the termination condition includes: the number of PVT solutions reaches a preset number of times; or, the new PVT solution result is the valid PVT solution result.
9. A receiver, applied to a satellite navigation system, characterized in that: The receiver is configured to: Receiving GNSS signals sent by satellites in the satellite navigation system; Based on the received GNSS signals, spoofing detection is performed on visible satellites by the method for satellite spoofing detection according to any one of claims 1 to 8.
10. A non-transitory computer storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for detecting satellite spoofing as claimed in any one of claims 1 to 8 is implemented.
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