GNSS interference detection method based on a navigation receiver

Abstract

The application discloses a kind of GNSS interference detection methods based on navigation receiver, comprising: obtaining the original observation information of navigation receiver and the elevation angle information of each satellite output;Set an observation window, in the observation window, the number of satellites tracked is counted for each frequency point of each GNSS system, and the mean value of the number of visible satellites is recorded;For each frequency point of each GNSS system, the carrier-to-noise ratio of each satellite is counted, and the maximum value and the mean value are recorded;The standard deviation of the pseudo-range of each satellite is counted, and the mean value is recorded;At the current observation time, for each frequency point of each GNSS system, the new observation quantity is compared with the statistical value to judge whether interference occurs, and the disturbed frequency point and the interference type are reported;The application solves the problem that the sensitivity of traditional monitoring receiver is insufficient and GNSS interference cannot be effectively detected.

Description

Technical Field

[0001] This invention relates to the field of radio monitoring technology, and in particular to a GNSS interference detection method based on a navigation receiver. Background Technology

[0002] As GNSS applications become increasingly widespread in military and civilian fields, the GNSS radio electromagnetic environment is also becoming more complex. GNSS faces various intentional and unintentional interferences, which affect the navigation system's monitoring of the ground and normal user operation, posing a serious threat to the accuracy, availability, and integrity of satellite navigation. For navigation satellites tens of thousands of kilometers away from the ground, due to limitations in battery power and lifespan, the transmitted signal power becomes extremely weak by the time it reaches the ground. At this point, the navigation signal is easily affected by various electromagnetic interferences. Conventional digital monitoring receivers and monitoring methods cannot detect such interference. However, GNSS navigation receivers have higher sensitivity, and their output raw observation information can reflect the interference situation of the navigation signal to a certain extent. Therefore, researching GNSS interference detection methods based on navigation receivers can compensate for the shortcomings of traditional monitoring receivers and is of great significance. Summary of the Invention

[0003] To address the problems existing in the prior art, the purpose of this invention is to provide a GNSS interference detection method based on a navigation receiver, which solves the problem that traditional monitoring receivers are not sensitive enough to effectively detect GNSS interference.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a GNSS interference detection method based on a navigation receiver, comprising the following steps:

[0005] Step 1: Obtain the raw observation information from the navigation receiver and the elevation angle information of each satellite output;

[0006] Step 2: Set up an observation window. Within the observation window, count the number of satellites tracked for each frequency point of each GNSS system, and record the average number of visible satellites, denoted as N. avg For each frequency point of each GNSS system, the carrier-to-noise ratio of each satellite is calculated, and its maximum and average values ​​are recorded, denoted as CN0. max With CN0 avg Calculate the pseudorange standard deviation for each satellite, record its mean, and denot it as Pstd. avg ;

[0007] Step 3: At the current observation time, for each frequency point of each GNSS system, compare the new observations with the statistical values ​​to determine whether interference has occurred, and report the interfered frequency points and interference types.

[0008] As a further improvement of the present invention, step 3 specifically includes the following steps:

[0009] (1) At the current observation time, the number of visible stars at frequency point i is N. If N = 0 or N avg -N > N th , it is determined that this frequency point is subject to jamming. N th is the set threshold value, and the value range is [1, N avg ;

[0010] (2) At the current observation time, let Na = 0 and Nm = 0. Compare the carrier-to-noise ratio CN0 of all visible stars at frequency point i with the statistical value in turn. If CN0 avg -CN0 > Pa th , then Na = Na + 1. If CN0 - CN0 max > Pm th , then Nm = Nm + 1 until all visible stars at this frequency point are traversed. Among them, Pa th and Pm th are the minimum carrier-to-noise ratio fluctuation threshold and the maximum carrier-to-noise ratio fluctuation threshold;

[0011] (3) At the current observation time, let Np = 0. Compare the pseudorange standard deviation Pstd of all visible stars at frequency point i with the statistical value in turn. If Pstd - Pstd avg > Pstd th , then Np = Np + 1 until all visible stars at this frequency point are traversed. Among them, Pstd th is the pseudorange standard deviation fluctuation threshold;

[0012] (4) If Na > N / 2 and Np > N / 2, it is considered that this frequency point is subject to jamming; if Nm > N / 2 and Np < N / 3, it is considered that this frequency point is subject to spoofing interference;

[0013] (5) Repeat steps (1) - step (4) until all frequency points are traversed.

[0014] As a further improvement of the present invention, in step 1, the original observation information includes the carrier-to-noise ratio, pseudorange, carrier phase, Doppler, pseudorange standard deviation, and carrier phase standard deviation of each satellite tracked by the navigation receiver.

[0015] The beneficial effects of the present invention are:

[0016] By classifying, statistically analyzing, and judging the original observation information output by the navigation receiver, and evaluating separately according to the frequency point, the present invention can quickly and real-time judge GNSS interference, and can judge the interference type, which has important significance for GNSS interference detection and interference troubleshooting. Description of the Drawings

[0017] Figure 1 This is a flowchart of Embodiment 1 of the present invention;

[0018] Figure 2 This is a flowchart of Embodiment 2 of the present invention. Detailed Implementation

[0019] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0020] Example 1

[0021] like Figure 1 As shown, a GNSS interference detection method based on a navigation receiver mainly includes the following steps:

[0022] Step S1: Obtain the raw observation information of the navigation receiver, including the carrier-to-noise ratio, pseudorange, carrier phase, Doppler, pseudorange standard deviation and carrier phase standard deviation of each satellite tracked by the navigation receiver;

[0023] Step S2: Obtain the elevation angle information of each satellite output by the navigation receiver;

[0024] Step S3: Set an observation window; the duration of the observation window can be configured arbitrarily.

[0025] Step S4: Within the observation window, count the number of satellites tracked for each frequency point of each GNSS system, and record the average number of visible satellites, denoted as N. avg ;

[0026] Step S5: Within the observation window, for each frequency point of each GNSS system, calculate the carrier-to-noise ratio of each satellite, record its maximum and average values, and denote them as CN0. max With CN0 avg Calculate the pseudorange standard deviation for each satellite, record its mean, and denot it as Pstd. avg ;

[0027] Step S6: At the current observation time, for each frequency point of each GNSS system, compare the new observations with the statistical values ​​to determine whether interference has occurred. The specific steps are as follows:

[0028] Step S61: At the current observation time, the number of visible stars at frequency point i is N. If N = 0 or N avg -N>N th If so, it is determined that the frequency point is subject to suppression interference, N th The threshold value is set, and its range is [1, N]. avg It can be configured according to the actual environment;

[0029] Step S62: At the current observation moment, set Na = 0 and Nm = 0. Then, compare the carrier-to-noise ratio CN0 of all visible stars at frequency point i with the statistical value one by one. If CN0 avg - CN0 > Pa th , then Na = Na + 1. If CN0 - CN0 max > Pm th , then Nm = Nm + 1. Repeat this process until all visible stars at this frequency point have been traversed. Here, Pa th and Pm th are the minimum and maximum carrier-to-noise ratio fluctuation thresholds, which can be determined according to the actual environment;

[0030] Step S63: At the current observation moment, set Np = 0. Then, compare the pseudorange standard deviation Pstd of all visible stars at frequency point i with the statistical value one by one. If Pstd - Pstd avg > Pstd th , then Np = Np + 1. Repeat this process until all visible stars at this frequency point have been traversed. Here, Pstd th is the pseudorange standard deviation fluctuation threshold, which can be determined according to the actual environment;

[0031] Step S64: If Na > N / 2 and Np > N / 2, it is considered that this frequency point is under spoofing interference. If Nm > N / 2 and Np < N / 3, it is considered that this frequency point is under deception interference;

[0032] Step S65: Repeat S61 - S64 until all frequency points have been traversed;

[0033] Step S7: Report the interfered frequency points and interference types.

[0034] Embodiment 2

[0035] As Figure 2 shown, a GNSS interference detection method based on a navigation receiver includes the following steps:

[0036] 1. Obtain the original observation information of the navigation receiver, including the carrier-to-noise ratio, pseudorange, carrier phase, Doppler, pseudorange standard deviation, and carrier phase standard deviation of each satellite tracked by the navigation receiver.

[0037] 2. Obtain the elevation angle information of each satellite output by the navigation receiver.

[0038] 3. Set an observation window, and the time length of the observation window can be configured arbitrarily.

[0039] 4. Within the observation window, for each frequency point of each GNSS system, count the number of tracked satellites, record the mean value of the number of visible satellites, and denote it as N avg .

[0040] 5. In the observation window, for each frequency point of each GNSS system, the carrier-to-noise ratio of each satellite is statistically calculated, and its maximum value and mean value are recorded, denoted as CN0 max and CN0 avg ; the standard deviation of the pseudorange of each satellite is statistically calculated, and its mean value is recorded, denoted as Pstd avg ;

[0041] 6. At the current observation time, for each frequency point of each GNSS system, the new observables are compared with the statistical values to determine whether interference occurs. The specific steps are as follows:

[0042] 1) At the current observation time, the number of visible satellites at frequency point i is N. If N = 0 or N avg -N > N th , it is determined that this frequency point is under spoofing interference. N th is the set threshold value, and the value range is [1, N avg , which can be configured according to the actual environment.

[0043] 2) At the current observation time, let Na = 0 and Nm = 0. The carrier-to-noise ratio CN0 of all visible satellites at frequency point i is sequentially compared with the statistical value. If CN0avg - CN0 > Path, then Na = Na + 1. If CN0 - CN0max > Pmth, then Nm = Nm + 1 until all visible satellites at this frequency point are traversed. Here, Path and Pmth are the minimum and maximum carrier-to-noise ratio fluctuation thresholds, and their values can be determined according to the actual environment.

[0044] 3) At the current observation time, let Np = 0. The standard deviation of the pseudorange Pstd of all visible satellites at frequency point i is sequentially compared with the statistical value. If Pstd - Pstdavg > Pstdth, then Np = Np + 1 until all visible satellites at this frequency point are traversed. Here, Pstdth is the pseudorange standard deviation fluctuation threshold, and its value can be determined according to the actual environment.

[0045] 4) If Na > N / 2 and Np > N / 2, it is considered that this frequency point is under spoofing interference; if Nm > N / 2 and Np < N / 3, it is considered that this frequency point is under deception interference.

[0046] 5) Repeat 1)-4) until all frequency points are traversed.

[0047] 7. Report the interfered frequency points and interference types.

[0048] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A GNSS interference detection method based on a navigation receiver, characterized in that, Includes the following steps: Step 1: Obtain the raw observation information from the navigation receiver and the elevation angle information of each satellite output; Step 2: Set up an observation window. Within the observation window, count the number of satellites tracked for each frequency point of each GNSS system, and record the average number of visible satellites, denoted as N. avg ; For each frequency point of each GNSS system, the carrier-to-noise ratio of each satellite is calculated, and its maximum and average values ​​are recorded, denoted as CN0. max With CN0 avg Calculate the pseudorange standard deviation for each satellite, record its mean, and denot it as Pstd. avg ; Step 3: At the current observation time, for each frequency point of each GNSS system, compare the new observations with the statistical values ​​to determine whether interference has occurred, and report the interfered frequency points and interference types. Step 3 specifically includes the following steps: (1) At the current observation time, the number of visible stars at frequency point i is N. If N=0 or N avg -N>N th If so, it is determined that the frequency point is subject to suppression interference, N th The threshold value is set, and its range is [1, N]. avg ]; (2) At the current observation time, assuming Na=0 and Nm=0, the carrier-to-noise ratio CN0 of all visible stars at frequency point i is compared with the statistical value in turn. If CN0 avg - CN0 > Pa th Then Na = Na+1, if CN0 - CN0 max > Pm th Then Nm = Nm + 1, until all visible stars at that frequency point have been traversed, where Pa th With Pm th These are the minimum and maximum carrier-to-noise ratio fluctuation thresholds. (3) At the current observation time, assuming Np=0, compare the pseudorange standard deviation Pstd of all visible stars at frequency point i with the statistical value in turn. If Pstd-Pstd avg >Pstd th Then Np = Np + 1, until all visible stars at that frequency have been traversed, where Pstd th This is the threshold for pseudorange standard deviation fluctuation; (4) If Na > N / 2 and Np > N / 2, then the frequency point is considered to be subject to suppression interference; if Nm > N / 2 and Np < N / 3, then the frequency point is considered to be subject to deception interference. (5) Repeat steps (1)-(4) until all frequency points have been traversed.

2. The GNSS interference detection method based on a navigation receiver according to claim 1, characterized in that, In step 1, the raw observation information includes the carrier-to-noise ratio, pseudorange, carrier phase, Doppler, pseudorange standard deviation, and carrier phase standard deviation of each satellite tracked by the navigation receiver.

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