CN114415211A

CN114415211A - Method and system for detecting spoofing interference of GNSS receiver

Info

Publication number: CN114415211A
Application number: CN202210031045.XA
Authority: CN
Inventors: 潘峰; 吕博; 缪新育; 胡昌军; 李曙方
Original assignee: China Academy of Information and Communications Technology CAICT
Current assignee: China Academy of Information and Communications Technology CAICT
Priority date: 2022-01-12
Filing date: 2022-01-12
Publication date: 2022-04-29

Abstract

The application relates to a method and a system for detecting spoofing interference of a GNSS receiver, wherein the method comprises the following steps: the GNSS real signal received by the GNSS antenna is converted into a first path of GNSS output signal and a second path of GNSS output signal; transmitting the first path of GNSS output signal to a GNSS receiver; analyzing the first path of GNSS output signal to obtain a first time information message of the first path of GNSS output signal; transmitting the GNSS analog signal to a GNSS receiver; analyzing the GNSS analog signal to obtain a second time information message of the GNSS analog signal; and judging whether the deception interference exists according to the second path of GNSS output signal, the second time information message and the first time information message. By detecting the time performance of the output of the GNSS receiver, the detection of the deception jamming signal of the GNSS receiver under different application scenes is realized, and whether the GNSS receiver is deception jamming or not is detected more efficiently.

Description

Method and system for detecting spoofing interference of GNSS receiver

Technical Field

The present invention relates to the field of Satellite Navigation technologies, and for example, to a method and a System for detecting spoofing interference of a GNSS (Global Navigation Satellite System) receiver.

Background

At present, in the process of satellite navigation signal propagation, a navigation signal received by a receiver is always subjected to intentional or unintentional interference, which causes errors such as a positioning result, a time service result and the like of the receiver, so that the safety application of a satellite navigation system is gradually valued by a great number of users. Interference to satellite navigation receivers is largely divided into two main categories: suppressing interference and spoofing interference. The deception jamming is to generate deception satellite signals which are highly similar to real signals or forward the real satellite signals, and the primary goal of the deception jamming is to enable the GNSS terminal to obtain false information such as time, position and speed under a concealed condition so as to achieve the deception purpose. In contrast, spoofing jammers do not require too much power and are well concealed, which also makes the spoofing jammer more survivable. In part, spoofing is more harmful than jamming.

The general method for detecting deception jamming signals is mainly to detect according to signal characteristics, and comprises detection based on the principles of signal power, noise power, carrier-to-noise ratio, automatic gain control of signal energy, abnormal correlation output of a tracking loop, double-antenna carrier phase difference, double-antenna pseudo-range difference and the like, wherein the detection methods all depend on the characteristics of received signals, need to upgrade internal programs of a receiver, integrate corresponding detection algorithms, need additional receiving antennas for part of the algorithms to assist detection, and need to reasonably select according to specific application scenes according to different detection performances and detection costs of the algorithms. For different application scenarios, a corresponding method needs to be selected to have better detection performance, otherwise, a spoofed interference signal cannot be efficiently detected, and therefore, the universality of detecting spoofed interference according to the characteristics of the signal is to be studied more deeply.

In the related art, there are the following technical problems: the method for detecting the deception signal according to the interference signal characteristics selects different algorithms according to the requirements of the received signal under different scenes, and the detection method has poor universality aiming at different application scenes.

Disclosure of Invention

The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview nor is intended to identify key/critical elements or to delineate the scope of such embodiments but rather as a prelude to the more detailed description that is presented later.

The embodiment of the disclosure provides a method and a system for detecting deception jamming of a GNSS receiver, and the detection method can realize detection of deception jamming signals of the GNSS receiver in different application scenes and has good universality.

In some embodiments, a method of the present disclosure for detecting spoofing interference of a GNSS receiver comprises:

the GNSS real signal received by the GNSS antenna is converted into a first path of GNSS output signal and a second path of GNSS output signal;

transmitting the first path of GNSS output signal to a GNSS receiver;

analyzing the first path of GNSS output signal to obtain a first time information message of the first path of GNSS output signal;

transmitting the GNSS analog signal to a GNSS receiver;

analyzing the GNSS analog signal to obtain a second time information message of the GNSS analog signal;

and judging whether the deception interference exists according to the second path of GNSS output signal, the second time information message and the first time information message.

Optionally, the time information packet includes a PTP packet or a 1PPS + ToD packet; the PTP message is a precision time protocol message, and the 1PPS + ToD message is a pulse signal per second message at the current moment.

Optionally, the determining whether the spoofing interference exists according to the second path of GNSS output signal, the second time information packet, and the first time information packet includes:

determining first time precision according to the first time information message and the second path of GNSS output signals;

determining a second time precision according to the second time information message and the second path of GNSS output signal;

and judging whether deception jamming exists according to the first time precision and the second time precision.

Optionally, determining whether spoofing interference exists according to the first time precision and the second time precision includes:

in the case that the difference between the second time precision and the first time precision is greater than a first threshold, spoofing interference exists;

and in the case that the difference between the second time precision and the first time precision is smaller than the first threshold value, no deception jamming exists.

Optionally, the first time precision and the second time precision are standard deviation of time precision or peak-to-peak value of time precision.

The method for detecting the deception jamming of the GNSS receiver provided by the embodiment of the disclosure can realize the following technical effects: by detecting the time performance of the output of the GNSS receiver and not depending on the characteristics of the received signal, the detection of the deception jamming signal of the GNSS receiver under different application scenes can be realized, the universality is better, and whether the GNSS receiver is deception jamming or not can be detected more efficiently.

In some embodiments, a system of the present disclosure for detecting spoofing interference of a GNSS receiver, the system comprising:

the GNSS antenna is used for receiving GNSS real signals;

the power divider is used for converting the GNSS real signals received by the GNSS antenna into a first path of GNSS output signals and a second path of GNSS output signals;

the GNSS analog signal source is used for generating and outputting a GNSS analog signal;

the GNSS receiver is used for receiving a first path of GNSS output signal, generating a first time information message according to the first path of GNSS output signal, receiving the GNSS analog signal and generating a second time information message according to the GNSS analog signal;

and the test instrument is used for receiving the second path of GNSS output signal, the first time information message and the second time information message and detecting whether deception interference exists according to the second path of GNSS output signal, the first time information message and the second time information message.

Optionally, the GNSS analog signal source includes:

the satellite simulator is used for generating and outputting a GNSS analog signal;

the cesium clock is used for providing a reference frequency for the satellite simulator;

and the control device is used for controlling the satellite simulator.

The system for detecting the deception jamming of the GNSS receiver provided by the embodiment of the disclosure can realize the following technical effects: by the deception jamming detection system of the GNSS receiver, the deception jamming signals of the GNSS receiver under different application scenes can be detected without depending on the characteristics of the received signals, the universality is good, and whether the GNSS receiver is deception jamming or not can be detected more efficiently.

The foregoing general description and the following description are exemplary and explanatory only and are not restrictive of the application.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the accompanying drawings and not in limitation thereof, in which elements having the same reference numeral designations are shown as like elements and not in limitation thereof, and wherein:

fig. 1 is a block diagram illustrating a system for detecting spoofing interference of a GNSS receiver according to an embodiment of the disclosure.

Fig. 2 shows a flowchart of a method for detecting spoofing interference of a GNSS receiver according to an embodiment of the disclosure.

Fig. 3 is a diagram illustrating simulation results of first time accuracy information provided by an embodiment of the present disclosure.

Fig. 4 is a diagram illustrating a simulation result of second time precision information provided by an embodiment of the present disclosure.

Detailed Description

So that the manner in which the features and elements of the disclosed embodiments can be understood in detail, a more particular description of the disclosed embodiments, briefly summarized above, may be had by reference to the embodiments, some of which are illustrated in the appended drawings. In the following description of the technology, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, one or more embodiments may be practiced without these details. In other instances, well-known structures and devices may be shown in simplified form in order to simplify the drawing.

The terms "first," "second," and the like in the description and in the claims, and the above-described drawings of embodiments of the present disclosure, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the present disclosure described herein may be made. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.

The term "plurality" means two or more unless otherwise specified.

In the embodiment of the present disclosure, the character "/" indicates that the preceding and following objects are in an or relationship. For example, A/B represents: a or B.

The term "and/or" is an associative relationship that describes objects, meaning that three relationships may exist. For example, a and/or B, represents: a or B, or A and B.

The term "correspond" may refer to an association or binding relationship, and a corresponds to B refers to an association or binding relationship between a and B.

Fig. 1 shows a block diagram of a system for detecting spoofing interference of a GNSS receiver according to an embodiment of the present disclosure, which includes a GNSS antenna 1, a power divider 2, a GNSS analog signal source, a GNSS receiver (i.e., a device under test 3), and a test meter 4.

The GNSS antenna 1 is used to receive GNSS real signals. The power divider 2 is configured to convert the GNSS real signal received by the GNSS antenna into a first path of GNSS output signal (i.e., a normal GNSS signal) and a second path of GNSS output signal (i.e., a normal GNSS signal). The GNSS analog signal source is used for generating and outputting a GNSS analog signal. The GNSS receiver is used for receiving the first path of GNSS output signal, generating a first time information message according to the first path of GNSS output signal, receiving a GNSS analog signal and generating a second time information message according to the GNSS analog signal. The test instrument 4 is configured to receive the second path of GNSS output signal, the first time information packet, and the second time information packet, and detect whether spoofing interference exists according to the second path of GNSS output signal, the first time information packet, and the second time information packet.

The time information message is analyzed through a test instrument in the deception jamming detection system of the GNSS receiver, whether the GNSS receiver receives jamming of deception jamming signals is judged, the detection system does not depend on characteristics of received signals in the detection process, detection of the deception jamming signals of the GNSS receiver under different application scenes can be achieved, universality is good, and whether the GNSS receiver is subjected to deception jamming can be detected more efficiently.

The GNSS antenna tracks normal GNSS signals, the GNSS signals are signals from Beidou satellites in the sky or signals from GPS satellites, and the same two paths of GNSS output signals, namely a first path of GNSS output signals and a second path of GNSS output signals, are output through the power divider. The input insertion loss of the two channels of the power divider is very close to or consistent with each other. In this way, the power reception levels of the tester and the device under test (GNSS receiver) are consistent. And the two channels have good isolation, so that no crosstalk of signals between the two channels is ensured. The length of the coaxial cable between the power divider and the GNSS receiver (the tested device 3) is consistent with that between the power divider and the test instrument, so that the time delay of two paths of signals reaching the GNSS receiver is ensured to be consistent as much as possible, the performance of the GNSS receiver can be completely reflected by the time synchronization performance of the test, and no extra time delay difference can be brought.

Optionally, the test instrument may track the second path of GNSS output signal output by the power divider, and then receive the first time information and the second time information output by the GNSS receiver, respectively, and analyze and compare the two times of output time information to determine whether the GNSS receiver receives interference from the jamming signal.

Therefore, the first path of GNSS output signal and the GNSS analog signal received by the receiver can be ensured to use the same reference signal as a reference, and the result obtained by comparison when the test instrument carries out interference detection is more accurate.

Optionally, before the detection, both the GNSS receiver and the test instrument may be configured to normally track the GNSS antenna to receive the GNSS signal for at least 6 hours, and the cesium clock may be configured to start the GNSS antenna for at least 2 hours, and provide a frequency reference signal for the satellite simulator, so as to ensure that the system can normally receive the GNSS signal and generate a stable interference signal.

Therefore, after the GNSS receiver and the satellite simulator stably output signals, the detection of the dry interference signals is started to be executed, and the accuracy of the test result is ensured.

Optionally, the GNSS receiver receives the first GNSS output signal, analyzes the first GNSS output signal to obtain a first time information packet, outputs the first time information packet to the test instrument, analyzes the packet by the test instrument to obtain a first time accuracy, and stores corresponding data.

Optionally, before the GNSS analog signal is transmitted to the GNSS receiver, the GNSS receiver is disconnected from normally tracking the first path of GNSS output signal of the power divider, and meanwhile, the receiver receives the GNSS analog signal (interference signal) output by the satellite simulator, and after the GNSS analog signal is normally received, a second time information message output by the GNSS receiver is analyzed by the test instrument, so that a second time precision of the analysis is obtained, and corresponding data is stored.

Optionally, as shown in fig. 1, the GNSS analog signal source includes: the satellite simulator 5 can be used for generating and outputting GNSS analog signals; a cesium clock 6, which can be used to provide a reference frequency to the satellite simulator; the control device 7 may be used to control the satellite simulator, and the control device may be a display control device, such as a computer.

Therefore, under the control of a computer and the supply of a stable reference frequency by a cesium clock, the accurate control of the satellite simulator is realized, the GNSS analog signal can be dynamically adjusted according to the detection requirement, and the detection efficiency is improved.

For example, a cesium clock in a GNSS analog signal source provides a stable frequency reference to a satellite simulator, the satellite simulator is controlled by a computer to manufacture an artificial GNSS analog signal, i.e., a spoofed interference signal, wherein the position, power parameters, and the like of the interference signal are not limited, and only the time information is not completely consistent with the current time, the satellite simulator outputs the spoofed interference signal to a GNSS receiver.

Optionally, the time information packet includes a PTP packet or a 1PPS + ToD packet; the PTP message is a precision time protocol message, and the 1PPS + ToD message is a pulse signal per second message at the current moment. Wherein, 1PPS (one pulse per second) represents a pulse per second signal, Tod (time of day) represents a current time, and 1PPS + Tod may represent a time signal. Ptp (precision Time protocol) is an abbreviation for precision Time protocol, and may also represent Time information.

determining second time precision according to the second time information message and the second path of GNSS output signals;

and judging whether the deception jamming exists according to the first time precision and the second time precision.

Optionally, the first time precision and the second time precision are standard deviation of time precision or peak-to-peak value of time precision. For example, the first time precision or the second time precision may be an output time error.

Thus, the method of angular judgment of space (position, pseudo range, speed and the like) is replaced by the method of angular judgment of time, which is more beneficial to the detection of the civil satellite time service receiver. If the interference signal is detected frequently, the GNSS receiving signal can be temporarily turned off, and other time sources of keeping or tracking the ground can be carried out.

Fig. 2 shows a method for detecting spoofing interference of a GNSS receiver, the method comprising:

step S1, converting the GNSS real signal received by the GNSS antenna into a first path of GNSS output signal and a second path of GNSS output signal;

step S2, transmitting the first path of GNSS output signal to a GNSS receiver;

step S3, analyzing the first path of GNSS output signal to obtain a first time information message of the first path of GNSS output signal;

step S4, transmitting the GNSS analog signal to the GNSS receiver;

step S5, analyzing the GNSS analog signal to obtain a second time information message of the GNSS analog signal;

and step S6, judging whether deception interference exists according to the second path of GNSS output signal, the second time information message and the first time information message.

By detecting the time performance of the output of the GNSS receiver and not depending on the characteristics of the received signal, the detection of the deception jamming signal of the GNSS receiver under different application scenes can be realized, the universality is better, and whether the GNSS receiver is deception jamming or not can be detected more efficiently.

The GNSS antenna tracks normal GNSS signals, the GNSS signals are signals from Beidou satellites in the sky or signals from GPS satellites, and the same two paths of GNSS output signals, namely a first path of GNSS output signals and a second path of GNSS output signals, are output through the power divider. The input insertion loss of the two channels of the power divider is very close to or consistent with each other. Thus, the power reception levels of the tester and the GNSS receiver (device under test 3) are consistent. And the two channels have good isolation, so that no crosstalk of signals between the two channels is ensured. The length of the coaxial cable between the power divider and the GNSS receiver (the tested device 3) is consistent with that between the power divider and the test instrument, so that the time delay of two paths of signals reaching the GNSS receiver is ensured to be consistent as much as possible, the performance of the GNSS receiver can be completely reflected by the time synchronization performance of the test, and no extra time delay difference can be brought.

Therefore, the first path of GNSS output signal and the GNSS analog signal received by the receiver can be ensured to take the same reference signal (the second path of GNSS output signal) as a reference, and the result obtained by comparison when the test instrument carries out interference detection is more accurate.

Fig. 3 is a diagram illustrating simulation results of first time accuracy information provided by an embodiment of the present disclosure. Fig. 4 is a diagram illustrating a simulation result of second time precision information provided by an embodiment of the present disclosure. As can be seen from the simulation in fig. 3, the test result obtained by analyzing the first time information packet by the test instrument indicates that the test result of detecting the first GNSS output signal (normal GNSS signal) is: the test time is 23 minutes and 58 seconds, the number of samples is 1438, the standard deviation of the pulse per second of the first GNSS output signal is 1.6596ns (nanosecond) (first time accuracy) based on the time of the second GNSS output signal, the current time TOD of the measured signal is 2021-11-1812: 15:32 the same as the current time TOD of the reference signal, that is, the second deviation of the current time TOD deviation is 0 second (first time accuracy).

As can be seen from the simulation in fig. 4, the test result obtained by analyzing the second time information packet by the test instrument represents the test result of detecting the analog GNSS signal (interference signal): the standard deviation of the pulse per second deviation is 19619.1747ns (nanoseconds) (first time accuracy), the current time TOD of the analog GNSS signal is 2021-11-1809: 13:50, the current time TOD of the reference signal is 2021-11-0917: 37:38, i.e. the second deviation of the current time TOD is 747372s (seconds) (second time accuracy).

From the above test results, it can be seen that the difference between the first time accuracy of the first path of GNSS output signal and the second time accuracy of the analog GNSS output signal is large. The test meter can determine that the GNSS receiver (the device under test) has deception jamming.

For example, if the difference between the standard deviations of the pulse per second deviations of the first GNSS output signal and the output time result of the analog GNSS signal is greater than a first threshold, for example, the first threshold is 10ns, or the difference between the peak-to-peak values (i.e., the deviation ranges) of the pulse per second deviations of the first GNSS output signal and the output time result of the analog GNSS signal is greater than 150ns (nanoseconds), it is determined that the GNSS receiver has the spoofing interference signal. Or, if the difference between the second deviation of the TOD deviation at the current time of the output time result of the first GNSS output signal and the simulated GNSS signal is greater than a second threshold, for example, the second threshold is 0s, it is determined that the GNSS receiver has the deception jamming signal.

The above description and drawings sufficiently illustrate embodiments of the disclosure to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. Furthermore, the words used in the specification are words of description only and are not intended to limit the claims. As used in the description of the embodiments and the claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the term "and/or" as used in this application is meant to encompass any and all possible combinations of one or more of the associated listed. Furthermore, the terms "comprises" and/or "comprising," when used in this application, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Without further limitation, an element defined by the phrase "comprising an …" does not exclude the presence of other like elements in a process, method or apparatus that comprises the element. In this document, each embodiment may be described with emphasis on differences from other embodiments, and the same and similar parts between the respective embodiments may be referred to each other. For methods, products, etc. of the embodiment disclosures, reference may be made to the description of the method section for relevance if it corresponds to the method section of the embodiment disclosure.

Those of skill in the art would appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software may depend upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosed embodiments. It can be clearly understood by the skilled person that, for convenience and brevity of description, the specific working processes of the system, the apparatus and the unit described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

Claims

1. A method for detecting spoofing interference of a GNSS receiver, the method comprising:

transmitting the first path of GNSS output signal to a GNSS receiver;

transmitting the GNSS analog signal to a GNSS receiver;

2. The method of claim 1, wherein the time information message comprises a PTP message or a 1PPS + ToD message; the PTP message is a precision time protocol message, and the 1PPS + ToD message is a pulse signal per second message at the current moment.

3. The method of claim 1, wherein determining whether spoofing interference is present based on the second GNSS output signal, the second time information packet and the first time information packet comprises:

4. The method of claim 3, wherein determining whether spoof interference is present based on the first time accuracy and the second time accuracy comprises:

5. The method of claim 3, wherein the first temporal precision and the second temporal precision are a standard deviation of temporal precision or a peak-to-peak value of temporal precision.

6. A system for detecting spoofing interference of a GNSS receiver, the system comprising:

the GNSS antenna is used for receiving GNSS real signals;

7. The system of claim 6, wherein the GNSS analog signal source comprises:

and the control device is used for controlling the satellite simulator.

8. The system of claim 6, wherein the time information message comprises a PTP message or a 1PPS + ToD message; the PTP message is a precision time protocol message, and the 1PPS + ToD message is a pulse signal per second message at the current moment.

9. The system of claim 6, wherein the determining whether spoofing interference exists based on the second GNSS output signal, the second time information packet and the first time information packet comprises:

10. The system of claim 9, wherein the first temporal precision and the second temporal precision are a standard deviation of temporal precision or a peak-to-peak value of temporal precision.