阅读说明：本技术 一种基于天线阵的非压制gnss欺骗干扰检测抑制方法 (Non-suppression GNSS deception jamming detection suppression method based on antenna array ) 是由 唐凯 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种基于天线阵的非压制GNSS欺骗干扰检测抑制方法,包括：S1,欺骗信号检测,若无欺骗干扰,则进入步骤S4；S2,寻找一组真实信号；S3,以找的一组真实信号为基础,识别真实信号与欺骗信号；S4,利用真实信号的伪距或载波相位观测值进行定位解算。本发明的欺骗干扰检测抑制方法,抗欺骗防护能力强,不仅能够检测欺骗信号,还能够区分出真实信号和欺骗信号；只要真实信号未被干扰完全压制,接收机仍可正常工作,输出正确可用的位置时间结果。(The invention discloses a non-suppression GNSS deception jamming detection suppression method based on an antenna array, which comprises the following steps: s1, detecting a deception signal, and if no deception jamming exists, entering the step S4; s2, searching a group of real signals; s3, identifying real signals and deception signals based on the found group of real signals; and S4, positioning and resolving by using the pseudo range or the carrier phase observed value of the real signal. The deception jamming detection and suppression method has strong anti-deception protection capability, can detect deception signals and can distinguish real signals from deception signals; as long as the real signal is not completely suppressed by the interference, the receiver can still work normally and output the correct available position time result.)

1. A non-suppression GNSS deception jamming detection suppression method based on an antenna array is characterized by comprising the following steps:

s1, calculating the detection quantity of the deception signal based on the difference value between the carrier phase single difference measurement value and the carrier phase single difference expected value; determining a detection threshold according to the statistical characteristic of the detection quantity of the deception signal; when the detection quantity of the deception signal is higher than the detection threshold, judging that the deception interference exists at present;

s2, grouping all received signals to obtain a group of signal groups which are real signals;

s3, respectively combining the signals with unknown authenticity with the obtained real signals to form signal groups, sequentially calculating the detection quantity and detection threshold of deception signals of each group of signals, and comparing the detection quantity and detection threshold of the deception signals to distinguish the signals with unknown authenticity as real signals or deception information;

and S4, positioning and resolving by using the pseudo range or the carrier phase observed quantity of the real signal.

2. The antenna array-based non-throttled GNSS spoofing interference detection suppression method of claim 1, further comprising, in S1, when the spoofing signal detection amount is less than or equal to a detection threshold, determining that there is no spoofing interference currently, and performing S4.

3. The method for suppressing non-throttled GNSS spoofing interference detection and suppression based on antenna arrays of claim 1 wherein in S1 the carrier phase single difference measurement is calculated as follows:

wherein the content of the first and second substances,D^e＝[γ^e,1,…γ^e,N]；representing the single difference of carrier phases between adjacent array elements; λ is the carrier wavelength of the satellite signal;for detecting systemUnifying unit direction vectors between array elements j and array elements j +1 in the body coordinate system where the system is located, and superscript 'b' represents the body coordinate system; a^TRepresenting a vector transpose; gamma ray^e,iThe unit incident direction vector from a signal i to a detection system under the geocentric coordinate system is marked with 'e' to represent the geocentric coordinate system; r is a coordinate transformation matrix between a detection system body coordinate system and a geocentric coordinate system;for measuring noise, zero mean Gaussian distribution is obeyed; n represents the number of the current received signals; m represents the number of array elements;

the plane where the antenna array is located is defined as xoy plane of the body coordinate system, and then the above formula can be simplified as follows:

wherein, the matrixAnd R₂Respectively represent matrix A^bAnd R is a matrix formed by the first two rows of elements.

4. The method of claim 3, wherein in step S1, the expected single carrier phase difference value is calculated as follows:

wherein the content of the first and second substances,representing a coordinate rotation matrix R₂Is determined by the estimated value of (c), representing the desired direction of incidence of the real signal,indicating trusted location of receiver, p^e,i＝[xⁱ,yⁱ,zⁱ]^TIndicating the location of the ith satellite.

5. The antenna array-based non-throttled GNSS spoofing interference detection suppression method of claim 4, wherein in S1, the method for calculating the spoofing signal detection amount comprises:

calculating the difference value between the carrier phase single difference measurement value and the carrier phase single difference expected value as follows: e-phi_s

And acquiring a deception signal detection quantity T as follows:

wherein e is_nThe matrix Q is a vector of the first column of the difference matrix E, i.e. the difference between all the measured values of the carrier phase single differences of the signal n and the expected values of the carrier phase single differences_nIs e_nThe covariance matrix of (2).

6. The antenna array based non-throttled GNSS spoofing interference detection suppression method of claim 4, wherein in S1, the method for determining the detection threshold comprises:

when the received signals are all real signals, the signal incidence direction difference matrix E is equal to 0, so the vector E_nMean value of (a)_n0, thus e_nObeying 0 mean value combined Gaussian distribution, so that the detection quantity T obeys central chi-square distribution with the freedom degree of (M-1) N-6; mean value mu when there is a spoofed signal in the received signal_nNot equal to 0, at this time e_nObey non-zero mean value combined Gaussian distribution, so the detection quantity T obeys the degree of freedomA non-centric chi-square distribution with a non-centric parameter p of (M-1) N-6, wherein

According to the niemann-pearson criterion, the decision threshold can be determined by:

wherein, alpha is the false alarm probability; f (x | H)₀) Indicating a spoofed signal detection quantity T at H₀A probability density function under the condition; th is the determined detection threshold.

7. The antenna array-based non-throttled GNSS spoofing interference detection suppression method of claim 1, wherein the S2 specifically comprises:

s21, grouping the N current signals into a group of 4A group;the number of combinations is 4 selected from N;

s22, calculating the detection threshold th when only 4 signals exist₄(ii) a Let group number i be 1;

s23, comparing whether the group number i is larger than the array element number M, if not, entering S24, otherwise, entering S26;

s24, calculating the deception signal detection quantity T of the ith group signal_i；

S25, comparing the deception signal detection quantity T_iAnd a detection threshold th₄(ii) a Detecting amount T of deception signal if ith group signal_iIs less than the detection threshold th₄If the group of 4 signals is judged to be real signals, stopping searching; otherwise, adding 1 to the group number i, and entering S23;

s26, if all divide intoThe detection amount of the group's deception signals is higher than the detection threshold th₄If the number of the real signals in the current received signals is less than 4, marking the current received signals as deception signals, and capturing and tracking other pseudo code carrier intervals of the current tracking signals; and then proceeds to S21 to regroup the newly acquired signal.

8. The antenna array-based non-throttled GNSS spoofing interference detection suppression method of claim 1, wherein the S3 specifically comprises:

s31, based on the 4 real signals, respectively combining the L signals with unknown signal authenticity with the known 4 real signals to form a signal group, and forming a group with the number of the L signals being 5;

s32, calculating the detection threshold th when the number of signals is 5₅(ii) a Let group number j equal to 1;

s33, comparing whether the group number j is larger than L, if so, judging to end;

s34, calculating the deception signal detection quantity T of the jth group signal_j；

S35, judging the detection quantity T of the deception signal_jWhether it is higher than the detection threshold th₅If the signal is higher than the preset value, judging that the jth signal is a deception signal; otherwise, judging that the jth signal is a real signal;

s36, adding 1 to the group number j, and returning to S33.

Technical Field

The invention relates to the technical field of Satellite Navigation, in particular to a non-suppressed GNSS (Global Navigation Satellite System) deception jamming detection suppression method based on an antenna array.

Background

Currently, satellite navigation systems are widely used in various aspects of national life. However, GNSS signals arriving on the ground are weak, making them susceptible to interference. The deception jamming can output false position and time results through a control target receiver, and further control a target system, so that the hazard is the greatest. The current anti-spoofing method mainly focuses on detecting spoofing interference and only plays a role of warning. Only by suppressing the spoofed interference can the receiver be guaranteed to still work properly. Through the antenna array zero-setting technology, the gain of the deception signal in the incoming direction is adjusted to be 0, the influence of deception interference can be eliminated, but the power of a real signal near the gain 0 can be weakened at the same time, and the performance of a receiver is reduced, so the antenna array zero-setting technology is usually used in a scene of suppressing interference; in addition, the spoofed signals can be eliminated by using a 'same-address elimination' technology, but the method needs to accurately estimate parameters such as power, phase and the like of the spoofed signals, otherwise, the spoofed signals cannot be eliminated, and even the power of the spoofed signals is enhanced.

At present, the signal power of suppressing the deception jamming is far greater than that of a real signal, and the deception jamming is easy to detect; and the power of a deception signal broadcasted by non-suppression type deception jamming is slightly larger than that of a real signal, so that the deception signal has stronger concealment and is difficult to detect.

Disclosure of Invention

The invention provides a non-suppression GNSS deception jamming detection suppression method based on an antenna array, which is used for solving the problems of non-suppression deception jamming detection.

The technical scheme adopted by the invention for solving the technical problem is as follows:

a non-suppression GNSS deception jamming detection suppression method based on an antenna array comprises the following steps:

s1, calculating the detection quantity of the deception signal based on the difference value between the carrier phase single difference measurement value and the carrier phase single difference expected value; determining a detection threshold according to the statistical characteristic of the detection quantity of the deception signal; when the detection quantity of the deception signal is higher than the detection threshold, judging that the deception interference exists at present;

s2, grouping all received signals to obtain a group of signal groups which are real signals;

s3, respectively combining the signals with unknown authenticity with the obtained real signals to form signal groups, sequentially calculating the detection quantity and detection threshold of deception signals of each group of signals, and comparing the detection quantity and detection threshold of the deception signals to distinguish the signals with unknown authenticity as real signals or deception information;

and S4, positioning and resolving by using the pseudo range or the carrier phase observed quantity of the real signal.

Preferably, the method for suppressing non-suppressed GNSS spoofing interference detection based on antenna arrays further includes, in S1, when the spoofing signal detection amount is less than or equal to the detection threshold, determining that there is no spoofing interference currently, and executing S4.

Preferably, in S1, the carrier phase single difference measurement value is calculated as follows:

wherein the content of the first and second substances,D^e＝[γ^e,1,…γ^e,N]；representing the single difference of carrier phases between adjacent array elements; λ is the carrier wavelength of the satellite signal;the superscript 'b' represents a body coordinate system for a unit direction vector between an array element j and an array element j +1 under the body coordinate system where the detection system is located; a^TRepresenting a vector transpose; gamma ray^e,iThe unit incident direction vector from a signal i to a detection system under the geocentric coordinate system is marked with 'e' to represent the geocentric coordinate system; r is a coordinate transformation matrix between a detection system body coordinate system and a geocentric coordinate system;for measuring noise, zero mean Gaussian distribution is obeyed; n represents the number of the current received signals; m represents the number of array elements;

the plane where the antenna array is located is defined as xoy plane of the body coordinate system, and then the above formula can be simplified as follows:

wherein, the matrixAnd R₂Respectively represent matrix A^bAnd R is a matrix formed by the first two rows of elements.

Preferably, in S1, the method for calculating the expected carrier phase single difference value is as follows:

wherein the content of the first and second substances,representing a coordinate rotation matrix R₂Is determined by the estimated value of (c),representing the desired direction of incidence of the real signal,indicating trusted location of receiver, p^e,i＝[xⁱ,yⁱ,zⁱ]^TIndicating the location of the ith satellite.

Preferably, in S1, the method for calculating the detection amount of the spoofed signal includes:

calculating the difference value between the carrier phase single difference measurement value and the carrier phase single difference expected value as follows: e-phi_s

And acquiring a deception signal detection quantity T as follows:

wherein e is_nFor the first column vector of the difference matrix E, i.e. all carrier phase single difference measurements and carrier phase single difference expectations of the signal nDifference of values, matrix Q_nIs e_nThe covariance matrix of (2).

Preferably, in S1, the method for determining the detection threshold includes:

when the received signals are all real signals, the signal incidence direction difference matrix E is equal to 0, so the vector E_nMean value of (a)_n0, thus e_nObeying 0 mean value combined Gaussian distribution, so that the detection quantity T obeys central chi-square distribution with the freedom degree of (M-1) N-6; mean value mu when there is a spoofed signal in the received signal_nNot equal to 0, at this time e_nObeying a non-zero mean value joint Gaussian distribution, so that the detection quantity T obeys a non-central chi-square distribution with a non-central parameter rho and a degree of freedom (M-1) N-6, wherein

According to the niemann-pearson criterion, the decision threshold can be determined by:

wherein, alpha is the false alarm probability; f (x | H)₀) Indicating a spoofed signal detection quantity T at H₀A probability density function under the condition; th is the determined detection threshold.

Preferably, the S2 specifically includes:

s21, grouping the N current signals into a group of 4A group;the number of combinations is 4 selected from N;

s22, calculating the detection threshold th when only 4 signals exist₄(ii) a Let group number i be 1;

s23, comparing whether the group number i is larger than the array element number M, if not, entering S24, otherwise, entering S26;

S24, calculating the deception signal detection quantity T of the ith group of signals_i；

S25, comparing the deception signal detection quantity T_iAnd a detection threshold th₄(ii) a Detecting amount T of deception signal if ith group signal_iIs less than the detection threshold th₄If the group of 4 signals is judged to be real signals, stopping searching; otherwise, adding 1 to the group number i, and entering S23;

s26, if the detection quantity of the deception signal of all the packets is higher than the detection threshold th₄If the number of the real signals in the current received signals is less than 4, marking the current received signals as deception signals, and capturing and tracking other pseudo code carrier intervals of the current tracking signals; and then proceeds to S21 to regroup the newly acquired signal.

Preferably, the S3 specifically includes:

s31, based on the 4 real signals, respectively combining the L signals with unknown signal authenticity with the known 4 real signals to form a signal group, and forming a group with the number of the L signals being 5;

s32, calculating the detection threshold th when the number of signals is 5₅(ii) a Let group number j equal to 1;

s33, comparing whether the group number j is larger than L, if so, judging to end;

s34, calculating the deception signal detection quantity T of the jth group signal_j；

S35, judging the detection quantity T of the deception signal_jWhether it is higher than the detection threshold th₅If the signal is higher than the preset value, judging that the jth signal is a deception signal; otherwise, judging that the jth signal is a real signal;

s36, adding 1 to the group number j, and returning to S33.

The invention has the following beneficial effects:

the non-suppression GNSS deception jamming detection suppression method based on the antenna array has strong anti-deception protection capability, can detect deception signals and can distinguish real signals and deception signals; as long as the real signal is not completely suppressed by the interference, the receiver can still work normally and output the correct available position time result.

The present invention will be described in further detail with reference to the drawings and embodiments, but the present invention is not limited to the embodiments.

Drawings

FIG. 1 is a flow chart of the method of the present invention;

FIG. 2 is a spoofed signal presence detection flow diagram of the present invention;

FIG. 3 is a flow chart of the present invention for finding a set of real signals;

fig. 4 is a flow chart of the present invention true signal and spoof signal distinguishing process.

Detailed Description

The technical scheme of the invention is specifically explained below with reference to the accompanying drawings.

Referring to fig. 1, the method for suppressing non-suppressed GNSS spoofing interference detection based on an antenna array of the present embodiment includes the following steps:

s1, detecting a deception signal, and if no deception jamming exists, entering the step S4; the process flow of spoofed signal detection is shown in fig. 2 and includes the following steps:

s11, calculating a carrier phase single difference measured value phi; carrier phase single difference is defined as the difference between carrier phase measurements of the same signal at different elements of the array. And recording the number of the array elements as M, wherein all the array elements of the antenna array are on the same plane, and the number of the carrier phase single difference measurement values which are linearly independent for each received signal is M-1. Then for satellite signal i, the single difference in carrier phase between adjacent array elements can be expressed as:

wherein the content of the first and second substances,a carrier phase measurement value of the signal i at the array element j is obtained; λ is the carrier wavelength of the satellite signal;the superscript 'b' represents a body coordinate system for a unit direction vector between an array element j and an array element j +1 under the body coordinate system where the detection system is located; a^TRepresenting a vector transpose; gamma ray^e,iThe unit incident direction vector from a signal i to a detection system under the geocentric coordinate system is marked with 'e' to represent the geocentric coordinate system; r is a coordinate transformation matrix between a detection system body coordinate system and a geocentric coordinate system;is an integer and represents the fuzzy number of the whole cycle of the carrier;to measure noise, a zero mean gaussian distribution is followed.

For eliminating carrier phase single difference measurementsTerm, first estimate the carrier cycle ambiguity number using the following equation:

wherein sign (·) represents taking a symbol;represents rounding down; | represents taking the absolute value.

Thus, the carrier phase single difference measurement without whole cycle ambiguity can be obtained as:

assuming that the current number of received signals is N, all carrier phase single difference measurements can be arranged in a matrix form as:

wherein the content of the first and second substances,D^e＝[γ^e,1,…γ^e,N]。

the plane where the antenna array is located is defined as xoy plane of the body coordinate system, and then the above formula can be simplified as follows:

matrix in the formulaR₂Respectively represent matrix A^bAnd R is a matrix formed by the first two rows of elements.

S12, estimating the expected value phi of the carrier phase single difference_s(ii) a In order to estimate the expected carrier phase single difference, it is first necessary to obtain the expected incident direction of the true signalAnd coordinate rotation matrix R₂。

Recording the trusted position of the receiver asThe ith satellite position is p^e,i＝[xⁱ,yⁱ,zⁱ]^TThen, thenI | · | | represents calculating the euler distance; thus, it is possible to provide

By using least square algorithm, coordinate rotation matrix R can be obtained₂The estimated values of (c) are:

the carrier phase single difference expected value is therefore:

s13, calculating a deception signal detection quantity T; the difference value between the carrier phase single difference measured value and the expected value is used for constructing a deception signal detection quantity, and the difference value between the carrier phase single difference measured value and the expected value is as follows: e-phi_s. Then the detection amount of the spoofed signal is T:wherein e_nThe matrix Q is a vector of the first column of the difference matrix E, i.e. the difference between the single-difference measured value and the expected value of all carrier phases of the signal n_nIs e_nThe covariance matrix of (2).

S14, determining a deception signal detection threshold th; the spoofed signal detection threshold is determined based on statistical characteristics of the spoofed signal detection amount. When the received signals are all real signals, the signal incidence direction difference matrix E is equal to 0, so the vector E_nMean value of (a)_n0, thus e_nObeying 0 mean value combined Gaussian distribution, so that the detection quantity T obeys central chi-square distribution with the freedom degree of (M-1) N-6; mean value mu when there is a spoofed signal in the received signal_nNot equal to 0, at this time e_nObeying a non-zero mean value joint Gaussian distribution, so that the detection quantity T obeys a non-central chi-square distribution with a non-central parameter rho and a degree of freedom (M-1) N-6, whereinThe hypothesis test based on the detection quantity T is therefore:

according to the Neyman-Pearson criterion, the decision threshold can be determined by the following equation:

wherein, alpha is the false alarm probability; f (x | H)₀) Denotes T is in H₀A probability density function under the condition; th is the determined detection threshold.

S15, detecting and judging, wherein when the detection quantity is higher than the detection threshold, judging that the deception jamming exists currently; and when the detection quantity is smaller than the detection threshold, judging that no deception jamming exists currently.

S2, finding a group of real signals, the processing flow is shown in fig. 3, and the processing flow includes the following steps:

s21: all received signals are first grouped in order to form a matrix D^eIn full rank, the number of signals required is 4 or more, and therefore the number of signals in each group is defined as 4, and all received signals are divided intoAnd groups of 4 received signals each,the number of combinations is n selected from m;

s22, calculating the detection threshold th of only 4 signals according to the method in the step S14₄(ii) a Let group number i be 1;

s23, comparing whether the group number is larger than M, if not, entering S24, otherwise, entering S26;

s24, according to the method in the step S13, the detecting quantity T of the deception signal of the ith group of signals is calculated_i；

S25, comparing the deception signal detection quantity T_iAnd a detection threshold th₄(ii) a If the detected quantity T of the ith group signal_iIs less than the detection threshold th₄If the group of 4 signals is judged to be real signals, stopping searching; otherwise, the group number i is added with 1, and the process proceeds to S23;

s26, if all the groups detect the quantity T₄Are all higher than the detection threshold th₄If the number of the real signals in the current received signals is less than 4, the current received signals are marked as deception signals, and the receiver is controlled by a signal capturing and scheduling module of the receiverCapturing and tracking other pseudo code carrier intervals of the current received signal, wherein the signal is captured and tracked inevitably under the condition that the real signal is not interfered and is completely suppressed; and then proceeds to S21 to regroup the newly acquired signal.

S3, identifying real signals and deception signals based on the found group of real signals; the processing flow is shown in fig. 4, and specifically includes the following steps:

s31, based on the 4 true signals found in step S2, combining the L signals with unknown signal authenticity with the known 4 true signals to form a signal group, and forming a group with the number of L signals being 5;

s32, calculating the detection threshold th when the number of signals is 5 according to the method in the step S14₅(ii) a Let group number j equal to 1;

s33, comparing whether the group number is larger than L, if so, judging to end;

s34, calculating the detecting quantity T of the deception signal of the jth group of signals according to the method in the step S1_j；

S35, judging the authenticity of the jth signal; detection quantity T_jAbove the detection threshold th₅If yes, the jth signal is a deception signal; otherwise the jth signal is a true signal.

S36, add 1 to the group number j, and proceed to S33.

S4: and performing positioning calculation by using the pseudo range or the carrier phase observed value of the real signal.

The above is only one preferred embodiment of the present invention. However, the present invention is not limited to the above embodiments, and any equivalent changes and modifications made according to the present invention, which do not bring out the functional effects beyond the scope of the present invention, belong to the protection scope of the present invention.