阅读说明：本技术 一种基于双接收机载波相位差分的gnss欺骗干扰检测方法 (GNSS deception jamming detection method based on dual-receiver carrier phase difference ) 是由 尹继东 胡彦胜 陈自然 张启 于 2021-09-01 设计创作，主要内容包括：本发明公开了一种基于双接收机载波相位差分的GNSS欺骗干扰检测方法,包括：假设观测历元k时接收机A捕获的信号为真实信号；对接收机A相邻历元间载波相位观测值差分,建立载波时间单差方程,运用最小二乘法求得接收机A观测历元k时的位置；其次,通过接收机A与接收机B测站间、不同卫星间、相邻观测历元间载波相位观测值差分,建立载波相位三差模型；基于接收机A的位置计算出接收机B的位置；通过接收机A与接收机B之间的距离与真实基线长度对比,判别接收信号的真伪。本发明运用假设检验思想,通过两个接收机实现目标导航欺骗干扰信号的有效检测,检测效率高,操作方便,且接收机不需要增加额外的硬件设备,节约了接收机设计成本。(The invention discloses a GNSS deception jamming detection method based on double-receiver carrier phase difference, which comprises the following steps: assuming that a signal captured by the receiver A is a real signal when observing an epoch k; establishing a carrier time single difference equation for the difference of the observed values of the carrier phases between adjacent epochs of the receiver A, and solving the position of the receiver A when observing an epoch k by using a least square method; secondly, establishing a carrier phase three-difference model through carrier phase observed value difference between a receiver A and a receiver B measuring station, between different satellites and between adjacent observation epochs; calculating the position of the receiver B based on the position of the receiver A; and judging the authenticity of the received signal by comparing the distance between the receiver A and the receiver B with the length of the real base line. The invention uses hypothesis testing thought, realizes effective detection of the target navigation deception jamming signal through two receivers, has high detection efficiency and convenient operation, does not need to add extra hardware equipment to the receivers, and saves the design cost of the receivers.)

1. A GNSS deception jamming detection method based on dual-receiver carrier phase difference is characterized by comprising the following steps:

step 1: setting an initial detection condition based on the receiver A and the receiver B: assuming that a signal captured by the receiver A is a real signal when observing an epoch k;

step 2: establishing a carrier phase observation equation through carrier phase observation values of a receiver A and a receiver B;

and step 3: establishing a carrier time single difference equation for the difference of the observed values of the carrier phases between adjacent epochs of the receiver A, and obtaining the position of the receiver A by using a least square method;

and 4, step 4: establishing a carrier phase ternary difference model by measuring differences among stations, different satellites and adjacent epochs through a carrier phase observation equation of a receiver A and a receiver B;

and 5: based on the position of the receiver A, calculating the position of the receiver B by adopting a carrier phase three-difference model;

step 6: and judging the authenticity of the received signal by comparing the distance between the receiver A and the receiver B with the length of the real base line.

2. The method for detecting GNSS spoofing interference based on dual-receiver carrier phase difference according to claim 1, wherein step 3 is to establish a carrier time single-difference equation for the difference of the carrier phase observations between adjacent epochs of the receiver a, and obtain the position of the receiver a by using a least square method, specifically:

the receiver A performs difference on the carrier phase observed value of the same satellite signal when observing epoch k-1 and observing epoch k to obtain a carrier time single difference equation, and based on the position information of epoch k-1, the position of the receiver A when observing epoch k is obtained by using a least square method.

3. The GNSS deception jamming detection method based on dual-receiver carrier phase difference according to claim 1, wherein in step 3, it is assumed in step 1 that the signal captured by the receiver a in epoch k is a true signal, and the position information of epoch k-1 is used to calculate the position of the receiver a in epoch k when the number of observable satellites is n (n ≧ 4), specifically comprising:

step 301: establishing a quaternary nonlinear carrier time single difference equation;

step 302: because the position of the receiver A is known when the epoch k-1 is carried out, Taylor approximation expansion is carried out on the basis of the position result of the receiver A when the epoch k-1 is carried out, and a carrier time single difference equation is linearized;

step 302: and solving the linearized square carrier time single difference equation by using a least square method to obtain a positioning result of the receiver A in epoch k, namely the position of the receiver A in epoch k.

4. The GNSS deception jamming detection method based on dual receiver carrier phase difference as claimed in claim 3,

the quaternary nonlinear carrier time single-difference equation of step 301 is established as follows:

the carrier phase observed values of the receiver A to the ith satellite when observing the epoch k-1 and the observation epoch k are respectively:

wherein the content of the first and second substances,to observe the carrier phase observation of receiver a at epoch m,for the geometric distance, deltat, of the satellite i to the receiver A for the observation of epoch m_A,u,mTo observe the clock offset of receiver a at epoch m,the clock error of the satellite i when the epoch m is observed; c is the speed of light, λ is the carrier wavelength,to observe the ionospheric delay error corresponding to receiver a at epoch m,to observe the tropospheric delay error corresponding to receiver a at epoch m,the receiver A is carrier phase measurement noise when observing an epoch m, wherein m is k, k-1;

correcting the carrier phase observation value by using an ionosphere delay correction model, a troposphere delay correction model and a satellite clock error;

according to the formulas (1) and (2), the carrier time single difference equation of the receiver A to the ith satellite signal at the observation epochs k and k-1 is obtained as follows:

wherein the content of the first and second substances,Δδt_A,u,k＝δt_A,u,k-δt_A,u,k-1，

5. the GNSS deception interference detection method based on dual-receiver carrier phase difference as claimed in claim 1, wherein in step 4, a carrier phase ternary difference model is established by a carrier phase observation equation of a receiver A and a receiver B through differences between measurement stations, different satellites and adjacent epochs, specifically:

at the same moment, the receiver A and the receiver B respectively carry out difference on carrier phase observed values corresponding to the same satellite signal to obtain a single difference observation equation, and carry out difference on the single difference observation equation once again to obtain a double difference observation equation, and further carry out difference on the double difference observation equation when the epoch k and the epoch k-1 exist to establish a carrier phase triple difference model.

6. The GNSS deception jamming detection method based on dual-receiver carrier phase difference is characterized in that, in step 4, the carrier phase difference model is established as follows:

establishing a carrier phase observation equation of the receiver B for the ith satellite signal in an observation epoch k-1 and an observation epoch k;

correcting the carrier phase observation value by using an ionosphere delay model, a troposphere delay model and a satellite clock error;

the receiver A and the receiver B respectively carry out difference on the observed values of the carrier phases of the ith satellite signal in epoch k, and the obtained single difference observation equation between the carrier stations is as follows:

wherein the content of the first and second substances,Δδt_AB,u,k＝δt_A,u,k-δt_B,u,k，

secondly, the receiver A and the receiver B respectively carry out difference on the observed values of the carrier phases when the receiver A and the receiver B carry out signal epoch k of the jth satellite, and the obtained single difference observation equation between the carrier stations is as follows:

wherein the content of the first and second substances,Δδt_AB,u,k＝δt_A,u,k-δt_B,u,k，

and (5) carrying out inter-satellite difference on the single-difference observation equation according to the formulas (4) and (5) to obtain a carrier phase double-difference observation equation:

wherein the content of the first and second substances,

and then carrying out difference on the (6) type carrier phase double-difference observation equation when the epoch k-1 and the epoch k are carried out, and establishing a carrier phase triple-difference model as follows:

wherein the content of the first and second substances,

7. the GNSS deception jamming detection method based on dual-receiver carrier phase difference as claimed in claim 1, wherein step 5 is to calculate the position of receiver B using a carrier phase three-difference model based on the position of receiver a, specifically:

and (3) iterating to obtain the position of the receiver B at the epoch k by adopting a carrier phase three-difference model according to the position of the receiver A at the epoch k.

8. The method as claimed in claim 1, wherein in step 5, based on the position of the receiver a at epoch k, when the number of observable satellites is n (n ≧ 3), the position of the receiver B at epoch k is calculated, which specifically includes:

step 501: taking the position of the receiver A in epoch k as a basis, combining the positions of the ith satellite and the jth satellite, performing Taylor approximate expansion on an equation set of a carrier phase ternary difference model, and linearizing the equation set;

step 502: and (5) iteratively solving an equation set of the linearized carrier phase ternary difference model to obtain the position of the receiver B epoch k.

9. The GNSS deception interference detection method based on dual-receiver carrier phase difference as claimed in claim 1, wherein in step 6, it is determined whether the distance between receiver A and receiver B is equal to the base length AB, if so, the signal captured by the receiver is a true signal, otherwise, the signal captured by the receiver is a deception signal.

Technical Field

The invention belongs to the technical field of satellite navigation anti-interference, and particularly relates to a GNSS deception interference detection method based on carrier phase difference of a double receiver (double antennas).

Background

With the development of information technology, Global Navigation Satellite Systems (GNSS) have been widely applied to important fields such as finance, civil aviation, urban traffic, and weapon precision guidance. However, GNSS signals are extremely weak when arriving at the ground, and ground receiving equipment is susceptible to interference, wherein deceptive interference is of great concern due to its high concealment and harmfulness. Under the condition of deception jamming, how to ensure that a target receiver still has reliable and correct positioning information is crucial, and an effective deception jamming detection technology is a premise for realizing GNSS anti-deception jamming and is an effective measure for ensuring GNSS information safety.

In general, a method for detecting spoofed interference by using antenna technology needs to use multiple antenna arrays and assume that spoofed interference signals come from the same direction, or needs to add an additional inertial measurement unit to acquire multi-antenna attitude information. When the deception jamming signal comes from different directions, effective detection cannot be carried out, namely the detection has limitation, and the receiver is large in size and high in detection cost.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a GNSS deception jamming detection method based on dual-receiver carrier phase difference, aiming at the defects of the prior art, based on the thought of hypothesis test, the GNSS deception jamming detection is realized by using dual receivers under the conditions of reducing the detection cost of the receivers and improving the detection efficiency, and the rapid detection and identification of deception jamming signals are realized. The detection capability of the target receiver for resisting the deceptive interference is improved.

In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows:

a GNSS deception jamming detection method based on dual-receiver carrier phase difference comprises the following steps:

step 1: setting an initial detection condition based on the receiver A and the receiver B: assuming that a signal captured by the receiver A is a real signal when observing an epoch k;

step 2: establishing a carrier phase observation equation through carrier phase observation values of a receiver A and a receiver B;

and step 3: establishing a carrier time single difference equation for the difference of the observed values of the carrier phases between adjacent epochs of the receiver A, and obtaining the position of the receiver A by using a least square method;

and 4, step 4: establishing a carrier phase three-difference model through carrier phase observation equations of a receiver A and a receiver B and differences among stations, satellites and adjacent epochs;

and 5: based on the position of the receiver A, calculating the position of the receiver B by adopting a carrier phase three-difference model;

step 6: and judging the authenticity of the received signal by comparing the distance between the receiver A and the receiver B with the length of the real base line.

In order to optimize the technical scheme, the specific measures adopted further comprise:

in the above step 3, the difference of the observed values of the carrier phases between adjacent epochs of the receiver a is established, a carrier time single difference equation is established, and the position of the receiver a is obtained by using a least square method, specifically:

the receiver A performs difference on the carrier phase observed value of the same satellite signal when observing epoch k-1 and observing epoch k to obtain a carrier time single difference equation, and based on the position information of epoch k-1, the position of the receiver A when observing epoch k is obtained by using a least square method.

In the step 3, assuming that the signal acquired by the receiver a in epoch k is a real signal according to the step 1, calculating the position of the receiver a in epoch k by using the position information of epoch k-1 when the number of observable satellites is n (n is greater than or equal to 4), specifically including:

step 301: establishing a quaternary nonlinear carrier time single difference equation;

step 302: because the position of the receiver A is known when the epoch k-1 is carried out, Taylor approximation expansion is carried out on the basis of the position result of the receiver A when the epoch k-1 is carried out, and a carrier time single difference equation is linearized;

step 302: and solving the linearized square carrier time single difference equation by using a least square method to obtain a positioning result of the receiver A in epoch k, namely the position of the receiver A in epoch k.

The quaternary nonlinear carrier time single-difference equation in step 301 is established as follows:

the carrier phase observed values of the receiver A to the ith satellite when observing the epoch k-1 and the observation epoch k are respectively:

wherein the content of the first and second substances,to observe the carrier phase observation of receiver a at epoch m,for the geometric distance, deltat, of the satellite i to the receiver A for the observation of epoch m_A,u,mTo observe the clock offset of receiver a at epoch m,observing the clock error of the satellite i when the epoch m is acquired; c is the speed of light, λ is the carrier wavelength,to observe the ionospheric delay error corresponding to receiver a at epoch m,to observe the tropospheric delay error corresponding to receiver a at epoch m,receiver a is carrier phase measurement noise for the observation epoch m, m being k, k-1.

Correcting the carrier phase observation value by using an ionosphere delay correction model, a troposphere delay correction model and a satellite clock error;

according to the formulas (1) and (2), the carrier time single difference equation of the receiver A to the ith satellite signal at the observation epochs k and k-1 is obtained as follows:

wherein the content of the first and second substances,Δδt_A,u,k＝δt_A,u,k-δt_A,u,k-1，

in the above step 4, the carrier phase triple difference model is established by using the carrier phase observation equation of the receiver a and the receiver B and by using the difference between the measurement stations, between different satellites and between adjacent epochs, specifically:

at the same moment, the receiver A and the receiver B respectively carry out difference on carrier phase observed values corresponding to the same satellite signal to obtain a single difference observation equation, and carry out difference on the single difference observation equation once again to obtain a double difference observation equation, and further carry out difference on the double difference observation equation when the epoch k and the epoch k-1 exist to establish a carrier phase triple difference model.

The method for establishing the carrier phase three-difference model in the step 4 comprises the following steps:

establishing a carrier phase observation equation of the receiver B for the ith satellite signal in an observation epoch k-1 and an observation epoch k;

correcting the carrier phase observation value by using an ionosphere delay model, a troposphere delay model and a satellite clock error;

the receiver A and the receiver B respectively carry out difference on the observed values of the carrier phases of the ith satellite signal in epoch k, and the obtained single difference observation equation between the carrier stations is as follows:

wherein the content of the first and second substances,Δδt_AB,u,k＝δt_A,u,k-δt_B,u,k，

secondly, the receiver A and the receiver B respectively carry out difference on the observed values of the carrier phases when the receiver A and the receiver B carry out signal epoch k of the jth satellite, and the obtained single difference observation equation between the carrier stations is as follows:

wherein the content of the first and second substances,Δδt_AB,u,k＝δt_A,u,k-δt_B,u,k，

and (5) carrying out inter-satellite difference on the single-difference observation equation according to the formulas (4) and (5) to obtain a carrier phase double-difference observation equation:

wherein the content of the first and second substances,

and then carrying out difference on the (6) type carrier phase double-difference observation equation when the epoch k-1 and the epoch k are carried out, and establishing a carrier phase triple-difference model as follows:

wherein the content of the first and second substances,

the step 5 of calculating the position of the receiver B by using the carrier phase three-difference model based on the position of the receiver a specifically includes:

and (3) iterating to obtain the position of the receiver B at the epoch k by adopting a carrier phase three-difference model according to the position of the receiver A at the epoch k.

In the step 5, based on the position of the receiver a in epoch k, when the number of observable satellites is n (n ≧ 3), the position of the receiver B in epoch k is calculated, which specifically includes:

step 501: and (3) based on the position of the receiver A in epoch k, combining the positions of the ith satellite and the jth satellite, performing Taylor approximate expansion on the equation set of the carrier phase ternary difference model, and linearizing the equation set.

Step 502: and (5) iteratively solving an equation set of the linearized carrier phase ternary difference model to obtain the position of the receiver B epoch k.

In the above step 6, it is determined whether the distance between the receiver a and the receiver B is equal to the base length AB, if so, the signal captured by the receiver is a real signal, otherwise, the signal captured by the receiver is a spoofed signal.

The invention has the following beneficial effects:

the invention uses hypothesis test thought, realizes effective detection of target navigation deception jamming signals through two receivers, has high detection efficiency and convenient operation compared with the prior detection technology based on the antenna array, does not need to add extra hardware equipment for the receivers, and saves the design cost of the receivers.

Drawings

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

Detailed Description

Embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

Referring to fig. 1, a GNSS spoofing interference detection method based on dual receiver carrier phase difference of the present invention includes:

step 1: setting an initial detection condition based on the receiver A and the receiver B: assuming that a signal captured by the receiver A is a real signal when observing an epoch k;

step 2: establishing a carrier phase observation equation through carrier phase observation values of a receiver A and a receiver B;

and step 3: establishing a carrier time single difference equation for the difference of the observed values of the carrier phases between adjacent epochs of the receiver A, and obtaining the position of the receiver A by using a least square method;

and 4, step 4: establishing a carrier phase three-difference model through carrier phase observation equations of a receiver A and a receiver B and differences among stations, satellites and adjacent epochs;

and 5: based on the position of the receiver A, calculating the position of the receiver B by adopting a carrier phase three-difference model;

step 6: and judging the authenticity of the received signal by comparing the distance between the receiver A and the receiver B with the length of the real base line.

In an embodiment, in step 3, the difference of the observed values of the carrier phases between adjacent epochs of the receiver a is established, a carrier time single difference equation is established, and the position of the receiver a is obtained by using a least square method, specifically:

the receiver A performs difference on the carrier phase observed value of the same satellite signal when observing epoch k-1 and observing epoch k to obtain a carrier time single difference equation, and based on the position information of epoch k-1, the position of the receiver A when observing epoch k is obtained by using a least square method.

In step 3, assuming that the signal captured by the receiver a in epoch k is a real signal according to step 1, calculating the position of the receiver a in epoch k by using the position information of epoch k-1 when the number of observable satellites is n (n is greater than or equal to 4), specifically comprising:

step 301: establishing a quaternary nonlinear carrier time single-difference equation through an equation (3);

step 302: because the position of the receiver A is known when the epoch k-1 is carried out, Taylor approximation expansion is carried out on the basis of the position result of the receiver A when the epoch k-1 is carried out, and a carrier time single difference equation is linearized;

step 302: and solving the linearized square carrier time single difference equation by using a least square method to obtain a positioning result of the receiver A in epoch k, namely the position of the receiver A in epoch k.

The quaternary nonlinear carrier time single-difference equation of step 301 is established as follows:

the carrier phase observed values of the receiver A to the ith satellite when observing the epoch k-1 and the observation epoch k are respectively:

wherein the content of the first and second substances,to observe the carrier phase observation of receiver a at epoch m,for the geometric distance, deltat, of the satellite i to the receiver A for the observation of epoch m_A,u,mTo observe the clock offset of receiver a at epoch m,the clock error of the satellite i when the epoch m is observed; c is the speed of light, λ is the carrier wavelength,to observe the ionospheric delay error corresponding to receiver a at epoch m,to observe the tropospheric delay error corresponding to receiver a at epoch m,receiver a is carrier phase measurement noise for the observation epoch m, m being k, k-1.

Correcting the carrier phase observation value by using an ionosphere delay correction model, a troposphere delay correction model and a satellite clock error;

according to the formulas (1) and (2), the carrier time single difference equation of the receiver A to the ith satellite signal at the observation epochs k and k-1 is obtained as follows:

wherein the content of the first and second substances,Δδt_A,u,k＝δt_A,u,k-δt_A,u,k-1，

in the embodiment, the step 4 of establishing a carrier phase triple difference model through a carrier phase observation equation of the receiver a and the receiver B and differences between stations, between stars and between adjacent epochs specifically includes:

at the same moment, the receiver A and the receiver B respectively carry out difference on carrier phase observed values corresponding to the same satellite signal to obtain a single difference observation equation, and carry out difference on the single difference observation equation once again to obtain a double difference observation equation, and further carry out difference on the double difference observation equation when the epoch k and the epoch k-1 exist to establish a carrier phase triple difference model.

The carrier phase three-difference model establishing method comprises the following steps:

similarly, establishing a carrier phase observation equation of the receiver B for the ith satellite signal in the observation epoch k-1 and the observation epoch k with the equation (1);

correcting the carrier phase observation value by using an ionosphere delay model, a troposphere delay model and a satellite clock error;

the receiver A and the receiver B respectively carry out difference on the observed values of the carrier phases of the ith satellite signal in epoch k, and the obtained single difference observation equation between the carrier stations is as follows:

wherein the content of the first and second substances,Δδt_AB,u,k＝δt_A,u,k-δt_B,u,k，

secondly, the receiver A and the receiver B respectively carry out difference on the observed values of the carrier phases when the receiver A and the receiver B carry out signal epoch k of the jth satellite, and the obtained single difference observation equation between the carrier stations is as follows:

wherein the content of the first and second substances,Δδt_AB,u,k＝δt_A,u,k-δt_B,u,k，

and (5) carrying out inter-satellite difference on the single-difference observation equation according to the formulas (4) and (5) to obtain a carrier phase double-difference observation equation:

wherein the content of the first and second substances,

and then carrying out difference on the (6) type carrier phase double-difference observation equation when the epoch k-1 and the epoch k are carried out, and establishing a carrier phase triple-difference model as follows:

wherein the content of the first and second substances,

in an embodiment, the step 5 of calculating the position of the receiver B by using a carrier phase three-difference model based on the position of the receiver a specifically includes:

and (3) iterating to obtain the position of the receiver B at the epoch k by adopting a carrier phase three-difference model according to the position of the receiver A at the epoch k.

In step 5, based on the position of the receiver a at epoch k, when the number of observable satellites is n (n is greater than or equal to 3), the position of the receiver B at epoch k is calculated, which specifically includes:

step 501: based on the position of the receiver A at the epoch k, combining the positions of the ith satellite and the jth satellite (obtained from satellite ephemeris data), the Taylor approximation of the equation system of the carrier phase three-difference model (equation (7)) is expanded, and the equation system is linearized.

Step 502: and (5) iteratively solving an equation set of the linearized carrier phase ternary difference model to obtain the position of the receiver B epoch k.

In an embodiment, the presence of a spoofed interfering signal will necessarily result in a carrier phase measurement that is different from the true value.

In the process of switching the signal from a real signal to a deception jamming signal, the clock error of the receiver jumps due to the influence of unstable and recaptured signals, so that the positioning result error of the carrier phase single-difference positioning method is increased in a short time. Compared with a carrier phase single-difference least square method positioning method, the three-difference model eliminates the influence of receiver clock difference. Therefore, under the assumption that the epoch k signal is true, the positioning value at the epoch k is calculated by the above two methods, and there are two cases:

(1) if the distance between the positioning results obtained by the two methods is approximately equal to the length of the actual base line, the signals captured by the receiver when the epoch k-1 and the epoch k are true;

(2) if the distance between the positioning results obtained by the two methods is not equal to the actual base length and is basically zero, the receiver captures the signal as a deception jamming signal when the epoch k-1 and the epoch k are determined.

That is, in step 6, it is determined whether the distance between the receiver a and the receiver B is equal to the base length AB, if so, the signal captured by the receiver is a real signal, otherwise, the signal captured by the receiver is a spoofed signal.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.