CN117665865A

CN117665865A - RDSS-assisted receiver spoofing detection method, device and terminal equipment

Info

Publication number: CN117665865A
Application number: CN202311627095.5A
Authority: CN
Inventors: 袁雪林; 李静; 陈正坤; 徐奕禹; 朱祥维; 戴志强
Original assignee: Sun Yat Sen University; Sun Yat Sen University Shenzhen Campus
Current assignee: Sun Yat Sen University; Sun Yat Sen University Shenzhen Campus
Priority date: 2023-11-30
Filing date: 2023-11-30
Publication date: 2024-03-08

Abstract

The invention discloses a RDSS (remote data service) -assisted receiver spoofing detection method, a device and terminal equipment, wherein the method comprises the following steps: performing spoofing detection on the GEO visible satellite through ephemeris consistency detection and pseudo-range consistency detection, calculating pseudo-range residual errors by using RDSS pseudo-range data of the visible GEO satellite and RNSS pseudo-range data of other visible satellites together to judge whether the residual visible GEO satellite and the other visible satellites are spoofed, further taking the received RDSS pseudo-range of the GEO satellite as a reference satellite, participating the reference satellite and the residual other visible satellites into least square residual error operation, and performing spoofing detection and identification on each other visible satellite. The invention improves the deception identification capability of the traditional RAI M method, so that under the condition of a large number of deception satellites, a plurality of deception satellites can be effectively identified one by one, and the accuracy and the detection effect of multi-satellite fault detection are improved.

Description

RDSS-assisted receiver spoofing detection method, device and terminal equipment

Technical Field

The invention relates to the technical field of global navigation satellites, in particular to a RDSS (radio data storage system) -assisted receiver spoofing detection method, device and terminal equipment.

Background

Many studies on GNSS spoofing detection methods exist today, and single parameter detection including traditional power detection, doppler detection, autonomous integrity detection, residual signal detection, etc. are effective for a certain spoofing interference pattern, and have great limitations when facing complex and diverse spoofing interference, such as array antenna spoofing detection based on an arrival angle, etc. and have higher equipment complexity requirements. There are many methods for assisting in fraud detection based on altimeters, inertial navigation, etc., and the information of external devices is added to assist in better fraud detection.

The deception jamming mainly comprises generative deception and forwarding deception, and the GNSS receiver can receive information such as wrong ephemeris, pseudo-range and the like, so that the receiver is interfered to calculate the position and clock error, and positioning and timing are affected.

The receiver autonomous integrity detection can better detect the condition of a small number of satellite faults, has been applied to a certain degree in many devices, is used for detecting satellite faults, has improved algorithms of RAIM, depends on the consistency of pseudo ranges, can realize better detection when the consistency relation of pseudo range solution is destroyed by deception, but in deception scenes, a plurality of satellites are often deception at the same time, the reliability of deception detection of the traditional least squares residual method RAIM at the moment can be greatly reduced, and if the pseudo range offset generated by deception parties has better consistency, the abnormality can not be detected completely or the satellites which are not normally deception can be judged as abnormal, so the effect of multi-satellite fault detection in the prior art is poor.

Disclosure of Invention

The embodiment of the invention provides a RDSS (remote data service) -assisted receiver spoofing detection method, device and terminal equipment, which can effectively solve the problem that the multi-satellite fault detection effect of the prior art is poor when a pseudo-range offset generated by a spoofing party has good consistency and even is possibly not detected completely or a satellite which is not spoofed normally is judged to be abnormal in the prior art.

An embodiment of the present invention provides a method for detecting receiver spoofing assisted by an RDSS, including:

receiving signal data respectively corresponding to GEO visible satellites capable of realizing RDSS positioning and other visible satellites incapable of realizing RDSS positioning; wherein the signal data includes: the method comprises the steps of (1) GEO visible satellites, RNSS ephemeris information and RDSS ephemeris information corresponding to other visible satellites, RNSS pseudo-ranges and RDSS pseudo-ranges corresponding to the GEO visible satellites, and RNSS pseudo-ranges corresponding to other visible satellites;

for each GEO visible satellite, when the received RNSS ephemeris information and RDSS ephemeris information are not consistent, storing the corresponding GEO visible satellite into a target array for storing the deceptive satellites;

for each GEO visible satellite which is not stored in the target array, calculating a pseudo-range difference according to the corresponding RNSS pseudo-range and RDSS pseudo-range, and storing the GEO visible satellite of which the pseudo-range difference is not in the first preset detection threshold range into the target array based on a comparison result of the pseudo-range difference and the first preset detection threshold range;

For each GEO visible satellite and each other visible satellite which are not stored in the target array, carrying out simultaneous equations on RDSS pseudo ranges of the GEO visible satellite and RNSS pseudo ranges of the other visible satellites according to a least squares residual method, solving the simultaneous equations to obtain a first pseudo-range residual, and storing the GEO visible satellite and the other visible satellites, of which the first pseudo-range residual is not in the second preset detection threshold range, in the target array according to a comparison result of the first pseudo-range residual and the second preset detection threshold range;

taking each GEO visible satellite which is not stored in the target array and the pseudo-range difference of which is within the first preset checking threshold range as a reference satellite, extracting other visible satellites which are not stored in the target array as target satellites, and performing deception detection on the target satellites according to the reference satellites until the other visible satellites which are not stored in the target array are extracted;

outputting the GEO visible satellites or other visible satellites with fraud in the target array one by one;

the method for performing deception detection on the target satellite according to the reference satellite comprises the following steps:

Performing simultaneous equations according to the RDSS pseudo range of the reference satellite and the RNSS pseudo range of the target satellite according to a least square residual method, and solving the simultaneous equations to obtain a second pseudo range residual; and after calculating the statistical detection amount according to the second pseudo-range residual error, comparing the statistical detection amount with a preset detection amount threshold, and storing other visible satellites of which the statistical detection amount is smaller than the preset detection amount threshold into the target array.

Preferably, the calculating a pseudo-range difference according to the corresponding RNSS pseudo-range and RDSS pseudo-range, storing GEO visible satellites whose pseudo-range difference is not in the first preset test threshold range into the target array based on a comparison result of the pseudo-range difference and the first preset test threshold range, includes:

and calculating a pseudo-range difference corresponding to the GEO visible satellite according to the following formula:

D _i ＝Prn _i -Prd _i ；

wherein D is _i As pseudo-range difference, prn _i For RNSS pseudoranges, prd _i Pseudo range for RDSS;

the first preset inspection threshold range is calculated according to the following formula:

wherein F is _D (x) For D _i Cumulative distribution function at x, P _fa To preset false alarm probability T ₁ To preset an upper threshold, T ₂ For a preset lower threshold, ΔT is a first preset test threshold range;

And storing the GEO visible satellites with the pseudo-range difference being larger or smaller than the first preset detection threshold range into the target array.

Preferably, the performing simultaneous equations on the RDSS pseudo-range of a GEO visible satellite and the RNSS pseudo-ranges of other visible satellites according to the least squares residual method, and calculating the simultaneous equations to obtain a first pseudo-range residual, includes:

obtaining simultaneous equations of RDSS pseudo-ranges of a GEO visible satellite and RNSS pseudo-ranges of other visible satellites according to the formula:

wherein, (x) _m ,y _m ,z _m ) Indicating the position of the mth satellite,the RDSS pseudoranges representing the mth satellite,RNSS pseudo-range, δt, representing the (m+1) -th satellite _u Representing receiver clock skew;

the simultaneous equations are solved based on a least squares residual method to obtain known quantities [ x, y, z, δt ] _u ]The first pseudorange residual is calculated according to the following formula:

Z＝GX _u +ξ；

X _u ＝[x,y,z,δt _u ] ^T ；

X _u ＝(G ^T G) ^-1 G ^T Z；

ω ₁ ＝[I _n -G(G ^T G) ^-1 G ^T ]Z；

wherein the method comprises the steps ofZ is the difference between the measured pseudo-range and the estimated value, the estimated value is calculated by the pseudo-range equation brought by the approximate position and clock deviation of the receiver, G is the observation geometric matrix, u is the number of the observation equations, X _u Is an estimated state vector, X _u The system comprises three position components and receiver clock bias, and ζ is an observation noise vector; omega ₁ For the first pseudorange residual, I _n Is an identity matrix with a dimension of n.

Preferably, the extracting the other visible satellites not yet stored in the target array as target satellites, and performing spoofing detection on the target satellites according to the reference satellites until the other visible satellites not yet stored in the target array are extracted, includes:

acquiring the total number of GEO visible satellites and other visible satellites which are not stored in the target array, and judging whether the first number of the reference satellites is not smaller than a second preset value when judging that the total number is larger than or equal to the first preset value;

if so, only one other visible satellite is extracted as a target satellite when the other visible satellite is extracted from the other visible satellites which are not stored in the target array, and deception detection is carried out on the target satellite according to the reference satellite until the other visible satellite which is not stored in the target array is extracted;

if not, taking the difference value between the first number of the reference satellites and the first preset value as a first target number, extracting other visible satellites corresponding to the first target number as target satellites, and performing deception detection on the target satellites according to the reference satellites; repeating the following target satellite extraction operations until other visible satellites which are not stored in the target array are extracted:

Judging whether the number of the target satellites without fraud is equal to the target difference value; the target difference value is the difference value between the second preset value and the reference satellite;

if the target satellite is equal to the target satellite, combining the target satellite without deception with each reference satellite to generate a new reference satellite combination, extracting one other visible satellite from other visible satellites which are not stored in the target array as a target satellite, and deceptively detecting the target satellite according to the new reference satellite combination;

if the number of the target satellites which are not deception is not equal to and is not less than the target difference value, combining the target satellites which are not deception with all the reference satellites to generate new reference satellite combinations, taking the difference value between the second number of the new reference satellite combinations and the first preset value as the second target number, extracting other visible satellites corresponding to the second target number as target satellites, and deception detection is carried out on the target satellites according to the new reference satellite combinations;

if the number of the target satellites which are not equal to and have no deception is larger than the target difference value, when the fact that a new reference satellite combination is not generated is judged, extracting the target satellites with the number corresponding to the target difference value, combining the target satellites with each reference satellite to generate a new reference satellite combination, extracting one other visible satellite from other visible satellites which are not stored in the target array as a target satellite, and deception detection is carried out on the target satellite according to the new reference satellite combination; and when the new reference satellite combination is judged to be generated, extracting one other visible satellite from other visible satellites which are not stored in the target array as a target satellite, and performing deception detection on the target satellite according to the new reference satellite combination.

Preferably, the calculating the statistical detection amount according to the second pseudo-range residual error includes:

the statistical detection amount is calculated according to the following formula:

SSE＝ω ₂ Tω ₂ ；

wherein SSE is the statistical detection quantity, ω is the second pseudo-range residual.

Preferably, the method further comprises:

outputting the GEO-visible satellite or other visible satellite with fraud in the target array when the total number is determined to be less than a first preset value.

On the basis of the method embodiment, the invention correspondingly provides the device item embodiment.

An embodiment of the present invention provides an RDSS-assisted receiver spoofing detection apparatus, including: the system comprises a signal data receiving module, an ephemeris consistency checking module, a pseudo-range consistency checking module, a first deception detecting module, a second deception detecting module and a deception detecting result output module;

the signal data receiving module is used for receiving signal data corresponding to GEO visible satellites capable of realizing RDSS positioning and other visible satellites incapable of realizing RDSS positioning respectively; wherein the signal data includes: the method comprises the steps of (1) GEO visible satellites, RNSS ephemeris information and RDSS ephemeris information corresponding to other visible satellites, RNSS pseudo-ranges and RDSS pseudo-ranges corresponding to the GEO visible satellites, and RNSS pseudo-ranges corresponding to other visible satellites;

The ephemeris consistency checking module is used for storing each GEO visible satellite into a target array for storing the deception satellites when the received RNSS ephemeris information and the RDSS ephemeris information are not consistent;

the pseudo-range consistency checking module is configured to calculate, for each GEO visible satellite that is not stored in the target array, a pseudo-range difference according to a corresponding RNSS pseudo-range and RDSS pseudo-range, and store, in the target array, GEO visible satellites for which the pseudo-range difference is not within a first preset checking threshold range based on a comparison result of the pseudo-range difference and the first preset checking threshold range;

the first spoofing detection module is configured to perform simultaneous equations on the RDSS pseudo range of a GEO visible satellite and the RNSS pseudo range of another visible satellite according to a least squares residual method for each GEO visible satellite not stored in the target array and each other visible satellite, calculate the simultaneous equations to obtain a first pseudo range residual, and store the GEO visible satellite and the other visible satellite, where the first pseudo range residual is not within the second preset detection threshold range, in the target array according to a comparison result of the first pseudo range residual and the second preset detection threshold range;

The second spoofing detection module is configured to extract other visible satellites that are not yet stored in the target array as target satellites by using, as reference satellites, all GEO visible satellites that are not yet stored in the target array and whose pseudo-range difference is within the first preset inspection threshold range, and perform spoofing detection on the target satellites according to the reference satellites until the other visible satellites that are not yet stored in the target array are extracted;

the deception detection result output module is used for outputting the GEO visible satellites or other visible satellites with deception in the target array one by one;

Based on the method embodiment, the invention correspondingly provides the terminal equipment item embodiment.

Another embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, where the processor executes the computer program to implement an RDSS-assisted receiver spoofing detection method according to the embodiment of the present invention.

The invention has the following beneficial effects:

the embodiment of the invention provides a RDSS (remote data service) -assisted receiver spoofing detection method, a device and terminal equipment, wherein the method comprises the following steps: receiving signal data respectively corresponding to GEO visible satellites capable of realizing RDSS positioning and other visible satellites incapable of realizing RDSS positioning; performing ephemeris consistency test on the GEO visible satellite according to the received RNSS ephemeris information and RDSS ephemeris information, performing pseudo-range consistency test on the corresponding RNSS pseudo-range and RDSS pseudo-range of the GEO visible satellite, and storing the GEO visible satellite with fraud into the target array; for each GEO visible satellite which is not stored in the target array and each other visible satellite, carrying out simultaneous equations on the RDSS pseudo range of one GEO visible satellite and the RNSS pseudo range of one other visible satellite according to a least squares residual method, and carrying out RAIM satellite deception detection on the GEO visible satellite and the other visible satellites; taking each GEO visible satellite passing the ephemeris consistency test as a reference satellite, extracting other visible satellites as target satellites, and performing deception detection on the target satellites according to the reference satellites until the other visible satellites which are not stored in the target array are extracted; outputting the GEO visible satellites or other visible satellites with fraud in the target array one by one. Compared with the prior art, the invention can accurately deception detection on a plurality of satellites, namely deception detection is carried out on GEO visible satellites through ephemeris consistency test and pseudo range consistency test, then the RDSS pseudo range data of the visible GEO satellites and RNSS pseudo range data of other visible satellites are used together to calculate pseudo range residual errors to judge whether deception exists between the residual visible GEO satellites and other visible satellites, in order to further accurately detect whether deception exists between the residual visible satellites and other visible satellites, after the pseudo range consistency test is carried out, the received RDSS pseudo range of the GEO satellites is used as a reference satellite, the reference satellite and the residual other visible satellites are participated in least square residual error operation, and grouping residual error test is carried out, so that deception detection capability of the least square residual error method is further improved, namely deception detection capability of the known RDSS is used as an aid, good consistency of pseudo range offset generated by deception parties can be well prevented, even abnormal situations can not be completely detected, namely, the traditional RAIM method can improve recognition capability of deception satellites one by one, and the deception detection effect is improved, and the deception detection can be carried out on a plurality of deception satellites effectively.

Drawings

Fig. 1 is a flowchart of an RDSS-assisted receiver spoofing detection method according to an embodiment of the present invention.

Fig. 2 is a flow chart of a receiver spoofing detection method according to another embodiment of the present invention.

Fig. 3 is a schematic flow chart of fraud detection for a target satellite according to a reference satellite according to an embodiment of the present invention.

Fig. 4 is a schematic diagram of a satellite extraction process according to an embodiment of the invention.

Fig. 5 is a schematic structural diagram of an RDSS-assisted receiver spoofing detecting apparatus according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Fig. 1 is a schematic flow chart of an RDSS assisted receiver spoofing detection method according to an embodiment of the present invention, where the RDSS assisted receiver spoofing detection method includes:

Step S1: receiving signal data respectively corresponding to GEO visible satellites capable of realizing RDSS positioning and other visible satellites incapable of realizing RDSS positioning; wherein the signal data includes: the method comprises the steps of (1) GEO visible satellites, RNSS ephemeris information and RDSS ephemeris information corresponding to other visible satellites, RNSS pseudo-ranges and RDSS pseudo-ranges corresponding to the GEO visible satellites, and RNSS pseudo-ranges corresponding to other visible satellites;

step S2: for each GEO visible satellite, when the received RNSS ephemeris information and RDSS ephemeris information are not consistent, storing the corresponding GEO visible satellite into a target array for storing the deceptive satellites;

step S3: for each GEO visible satellite which is not stored in the target array, calculating a pseudo-range difference according to the corresponding RNSS pseudo-range and RDSS pseudo-range, and storing the GEO visible satellite of which the pseudo-range difference is not in the first preset detection threshold range into the target array based on a comparison result of the pseudo-range difference and the first preset detection threshold range;

step S4: for each GEO visible satellite and each other visible satellite which are not stored in the target array, carrying out simultaneous equations on RDSS pseudo ranges of the GEO visible satellite and RNSS pseudo ranges of the other visible satellites according to a least squares residual method, solving the simultaneous equations to obtain a first pseudo-range residual, and storing the GEO visible satellite and the other visible satellites, of which the first pseudo-range residual is not in the second preset detection threshold range, in the target array according to a comparison result of the first pseudo-range residual and the second preset detection threshold range;

Step S5: taking each GEO visible satellite which is not stored in the target array and the pseudo-range difference of which is within the first preset checking threshold range as a reference satellite, extracting other visible satellites which are not stored in the target array as target satellites, and performing deception detection on the target satellites according to the reference satellites until the other visible satellites which are not stored in the target array are extracted;

performing simultaneous equations according to the RDSS pseudo range of the reference satellite and the RNSS pseudo range of the target satellite according to a least square residual method, and solving the simultaneous equations to obtain a second pseudo range residual; after calculating the statistical detection amount according to the second pseudo-range residual error, comparing the statistical detection amount with a preset detection amount threshold, and storing other visible satellites of which the statistical detection amount is smaller than the preset detection amount threshold into the target array;

step S6: outputting the GEO visible satellites or other visible satellites with fraud in the target array one by one.

As shown in fig. 2, the flow of the receiver spoofing detection method of the present invention is specifically as follows:

Step S1, the receiver receives a signal: a dual-mode receiver which simultaneously comprises RNSS and RDSS positioning functions is used for receiving satellite signals, the RNSS and RDSS pseudo-ranges of the visible satellites are calculated, and information such as carrier-to-noise ratio, ephemeris and the like is stored.

Step S2, ephemeris consistency test: judging whether the received RNSS and RDSS ephemeris information are consistent, comparing the ephemeris of GEO satellites in the visible satellites, and if not, judging that the RNSS satellite signals are deceptively generated by low-level generation;

step S3, pseudo-range consistency test: and calculating the pseudo-range difference between the RDSS and the RNSS of the receivable GEO satellite, detecting through a preset detection threshold, switching to S4 if the pseudo-range difference is smaller than the threshold, judging that the corresponding GEO satellite is deceptively received if the pseudo-range difference is larger than the threshold, and storing the deceptively received GEO satellite into an array to be displayed.

Step S4, RAIM satellite spoofing detection: and calculating pseudo-range data of the visible GEO satellite RDSS and pseudo-range data of other visible satellites RNSS together, calculating a first pseudo-range residual, setting a certain false alarm rate, calculating a hypothesis test threshold, comparing the first pseudo-range residual with a threshold, and judging that corresponding visible GEO satellite signals have deception when the first pseudo-range residual is larger than the threshold.

Step S5, RAIM satellite spoofing identification: if the number of the visible satellites is larger than or equal to a first preset value, taking the deception visible satellite obtained in the step S3 as a reference, and performing a random least square residual error method: assuming m visible GEO satellite signals, if m <4, randomly selecting 5-m satellites from the rest satellites each time to form a solution equation set, obtaining a solution SSE, and comparing the solution SSE with a detection threshold, if the solution SSE is larger than the detection threshold, judging that the satellites are deception, otherwise, judging that the satellites are normal satellites. Through multiple loops, all satellites that are being spoofed can be determined.

When m > =4, the rogue satellite can be directly determined by comparing the SSE calculated by selecting one satellite from the remaining satellites to the detection threshold at a time. Outputting the deception satellite in other visible satellites.

Wherein, when m <4, the specific cycle mode is: randomly selecting 5-m calculation residuals, if no deception signal is judged, extracting 4-m visible GEO satellites added with the previous m from the satellites without deception at present as the reference of an equation set, traversing the rest other visible satellites, and combining to form a solution equation set;

if the deception signal is judged to be contained in the deception signal, the next group of other visible satellites are continuously traversed until the deception-free combination is found, one other visible satellite is extracted for deception detection each time, and if the deception signal is not found after the traversing is finished, the other visible satellite signals are judged to be deception.

Step S6, outputting a satellite with fraud.

For step S1, in a preferred embodiment, the spoofing mainly includes generational spoofing and forwarded spoofing, which both cause the GNSS receiver to receive information such as ephemeris, pseudoranges, etc. that are erroneous, thereby interfering with the receiver' S solution to position and clock bias, and affecting positioning and timing.

The generated deception jamming can directly duplicate the radio frequency carrier wave, the pseudo code and the navigation data bit, because the GNSS civil signals corresponding to the information are public and transparent. By changing the values of the parameters, the receiver can generate wrong positioning time service results after capturing and tracking the deception signal by making them different from the real signal. According to the implementation complexity and the difficulty of detecting the deception jamming, the existing generated deception jamming can be divided into: primary, intermediate, and advanced generation type spoofing interference. The primary generation type deception is to directly interfere with the real signal through the false satellite signal generated by the simulator, and the used false signal information is generated by the simulator, is easy to distinguish from the real signal and is easy to detect. The second two kinds of information such as the true signal is received firstly, and then the partial pseudo range of the true signal is modified, so that the cheating is difficult to generate and detect, and the cheating is difficult to appear in the actual electromagnetic environment.

The forward deception is to broadcast the captured GNSS signals to the receiver through delay of a delay device and amplification of a power amplifier, so that the receiver obtains error information. The forwarding delay can be classified into a natural delay, which is a time delay due to a change in a signal transmission path, and an artificial delay, which is a delay for artificially joining in order to realize spoofing at a forwarding spoofing source.

The pseudo-range calculation error of the receiver can be caused by adding the time delay, so that deviation of a positioning time service result is caused, for the forward type deception, when a plurality of satellite signals are deception, the pseudo-range is offset by a certain value, the consistency of different satellite pseudo-ranges is destroyed, the forward type deception has wide application and simple realization, and is the most common deception mode in GNSS deception.

Beidou satellites can be classified into geostationary orbit (GEO) satellites, inclined geosynchronous orbit (IGSO) satellites, and medium circular earth orbit (MEO) satellites by orbital altitude. At present, china has transmitted 59, 60 and 61 No. 3 GEO satellites of the radio measurement service (Radio Determination Satellite Service, RDSS) of the Beidou three satellites, and a total of 8 GEO satellites are added with the original No. 1-5 GEO satellites of the Beidou two satellites to provide RDSS service services such as navigation positioning, short message communication, satellite time service, satellite-based augmentation and the like for navigation users. These GEO satellites may enable simultaneous positioning of RNSS signals and RDSS.

The Beidou RNSS positioning, namely satellite navigation positioning, requires 4 or more than 4 visible satellites to calculate four unknowns including three-dimensional positions and clock errors, and is a main mode for realizing high-precision positioning by receiving GNSS signals.

The Beidou RDSS positioning is double-star positioning, and the positioning system comprises two geostationary satellites, a user and a measurement control center (measurement control center, MCC). The specific working process of the double-star positioning is that MCC broadcasts continuous outbound signals to users through two geostationary satellites; after receiving the outbound signal, the user transmits a positioning application burst inbound signal at a designated time according to a protocol, and transmits the positioning application burst inbound signal to the MCC through satellite transfer; after the MCC receives the inbound signals, according to the time delay of the signals, calculating the bidirectional transmission time of the measurement signals from MCC to satellite to user to satellite, and calculating the distance from MCC to satellite to user, wherein the distance from MCC to satellite is known, so that the distance between the user and the satellite can be obtained, the distance between the two satellites and the user is calculated according to the method, and the elevation of the user equipment meeting the conditions is searched in the geography Gao Chengku stored by the MCC, so as to obtain the user coordinates; the MCC sends the user coordinate information to the user through the satellite to complete one-time positioning service.

The positioning of RDSS is limited in application because it uses only the features of two satellites, relies on accurate elevation data, and requires a lot of base station resources. RNSS has wider application in the location area, but is also vulnerable to fraud and attack, and when the RNSS is spoofed, the RDSS may keep the original results unaffected, so in some areas the RDSS may be used as an aid to spoof detection of the RNSS.

After the Beidou dual-mode receiver is started, capturing and tracking of signals by RNSS/RDSS can be simultaneously carried out, and signal data respectively corresponding to GEO visible satellites capable of realizing RDSS positioning and other visible satellites incapable of realizing RDSS positioning are received, wherein the signal data comprise RNSS ephemeris information and RDSS ephemeris information corresponding to the GEO visible satellites and other visible satellites, RNSS pseudo-ranges and RDSS pseudo-ranges corresponding to the GEO visible satellites and RNSS pseudo-ranges corresponding to other visible satellites; the receiver of the invention can also obtain the observed quantity of the carrier-to-noise ratio, the pseudo range, the Doppler, the carrier phase and the like of the RNSS and the RDSS at the same time, and can also obtain the ephemeris data of the corresponding satellites, including satellite positions and the like.

For step S2, in a preferred embodiment, it may be determined whether the RNSS has been subject to simple generative spoofing by detecting whether satellite positions in the GEO satellite signal ephemeris information are consistent. And when the received RNSS ephemeris information and RDSS ephemeris information are not consistent, storing the corresponding GEO visible satellite into a target array for storing the deceptive satellites so as to complete ephemeris consistency check.

For step S3, in a preferred embodiment, further spoofing detection is performed on GEO-visible satellites by pseudorange consistency verification, and the RNSS positioning module can simultaneously receive data of multiple satellites to obtain pseudoranges Pr for each satellite _i While the RDSS only receives part of the GEO satellite signals, the RDSS generally comprises at least two satellites, the satellite number received by the RDSS is set as m, and the corresponding RNSS pseudo range is Prn _m RDSS pseudo-range Prd _m Then the pseudoranges obtained by the two systems satisfy:

Prn _m -Prd _m ＝δ _m

wherein delta _m The system error representing two satellites, including measurement noise brought by two receiving modules, the system error of two positioning algorithms, etc., is generally not too large.

For other visible satellites, although there is no RDSS pseudorange to the corresponding satellites, these satellites still satisfy a certain relationship with Pr1 or Pr 2:

Pr _i *2-Pr1＝ΔPr _i +δ _m

where ΔPr represents the actual pseudorange difference between the receiver and the two satellites, which is a fixed value when the receiver is stationary and which is offset as the position of the receiver changes during movement.

Thus, for a visible GEO satellite i, under no fraud conditions, the difference between the pseudoranges of the RNSS and RDSS systems should be close to the systematic error, defining the pseudorange difference between RNSS and RDSS as:

D _i ＝Prn _i -Prd _i

The parameter will vary steadily with the motion of the receiver within the range of systematic errors, but when the satellite signal is spoofed, a large offset will occur, and by assuming a test threshold detection, it can be determined whether the satellite is spoofed.

D _i ＝Prn _i -Prd _i ；

Specifically, for GEO satellite n, the pseudo-range difference between RDSS and RNSS is in accordance with normal distribution, D _n ～N(0,σ2 _R )

Then D _i The probability density function at x is:

then D _i The cumulative distribution function at x can be expressed as:

the moving average detection model has an upper threshold T and a lower threshold T ₁ And T ₂ The two thresholds satisfy Δt=t ₁ ＝-T ₂ When the moving average is greater than the upper threshold or less than the lower threshold, then when the time difference is x, the false alarm probability can be expressed as:

If the false alarm probability P is set _fa Delta T can be reversely solved by the above formula, and then delta T and delta T are respectively the required upper and lower detection thresholds T ₁ And T ₂ 。

By taking the pseudo-range difference D _in And upper and lower threshold T ₁ And T ₂ Comparing if it is greater than the upper threshold T ₁ Or less than the lower threshold T ₂ Then consider the signal to be subjected toFraud is otherwise not present.

For step S4, in a preferred embodiment, in order to further accurately detect whether there is fraud in the remaining other visible satellites, the present invention performs more accurate fraud detection and identification on GEO visible satellites and other visible satellites through RAIM fraud detection after performing the pseudo-range consistency check.

The basic principle of RAIM technology anti-spoofing is to judge whether a spoofing signal exists or not by detecting consistency of redundant information between observables so as to exclude the spoofing signal from positioning solution. Strictly speaking, the measurement domain technique is not specific to spoofing, but rather more broadly determines whether the navigation signal is able to meet the integrity requirements.

Common RAIM algorithms include pseudorange comparison, parity check, least squares residual, and the like. The least square residual error method has small calculated amount and simple principle, and can achieve better detection effect in the detection of single-star faults or double-star faults. The method can also realize certain detection and recognition functions on the deception scene, wherein the detection refers to judging whether satellites in the visible satellites are deception, and the recognition refers to specific satellites which are deception.

The invention mainly combines RDSS pseudo-range information with least square residual RAIM to improve the detection capability of the algorithm on deception.

In a spoofing scenario, a plurality of satellites are often spoofed at the same time, at this time, the reliability of RAIM spoofing detection by a traditional least squares residual method is greatly reduced, and if the pseudo-range offsets generated by the spoofing party have good consistency, the anomaly may not be detected at all or the satellites which are not normally spoofed are judged to be anomalous. Therefore, the known RDSS is used as an aid to participate in RAIM operation without spoofing, so that the situation can be well avoided.

Z＝GX _u +ξ；

X _u ＝[x,y,z,δt _u ] ^T ；

X _u ＝(G ^T G) ^-1 G ^T Z；

ω ₁ ＝[I _n -G(G ^T G) ^-1 G ^T ]Z；

wherein Z is the difference between the measured pseudo-range and an estimated value, the estimated value is calculated by taking the receiver approximate position and clock bias into a pseudo-range equation, G is an observation geometric matrix, u is the number of observation equations, and X _u Is an estimated state vector, X _u The system comprises three position components and receiver clock bias, and ζ is an observation noise vector; omega ₁ For the first pseudorange residual, I _n Is an identity matrix with a dimension of n.

And the RDSS pseudo range of a GEO visible satellite and the RNSS pseudo ranges of other visible satellites can be subjected to simultaneous equations according to a least squares residual method, after the simultaneous equations are solved to obtain a first pseudo range residual, the GEO visible satellite and other visible satellites, the first pseudo range residual of which is not in the second preset detection threshold range, are stored in the target array according to a comparison result of the first pseudo range residual and the second preset detection threshold range.

For step S5, in a preferred embodiment, the received RDSS pseudo-range of the GEO satellite is used as a reference satellite, and the reference satellite and the remaining other visible satellites are involved in the least squares residual operation, so as to further accurately detect and identify whether the remaining other visible satellites are spoofed.

Firstly, taking each GEO visible satellite which is not stored in the target array and the pseudo-range difference of which is within the range of the first preset inspection threshold as a reference satellite, extracting other visible satellites which are not stored in the target array as target satellites, and performing deception detection on the target satellites according to the reference satellites until the other visible satellites which are not stored in the target array are extracted;

When the target satellite is deceptively detected, a simultaneous equation is carried out according to the RDSS pseudo range of the reference satellite and the RNSS pseudo range of the target satellite and a least square residual method, and the simultaneous equation is solved to obtain a second pseudo range residual; and after calculating the statistical detection amount according to the second pseudo-range residual error, comparing the statistical detection amount with a preset detection amount threshold, and storing other visible satellites of which the statistical detection amount is smaller than the preset detection amount threshold into the target array.

Specifically, as shown in fig. 3, the calculation process of the second pseudo-range residual error and the statistical detection amount is as follows:

the pseudorange between the ith satellite and the receiver may be expressed as:

wherein, (x) _i ,y _i ,z _i ) Indicating the position of the ith satellite, (x) _u ,y _u ,z _u ) Indicating where the receiver is located, t _u Is the advance of the receiver clock relative to the system time, t _u Is the advance of the clock of the ith satellite relative to the system time epsilon _i Is the pseudorange measurement error for the ith satellite.

Let the number of received satellites in view be N, where the number of GEO satellites is M, let RDSS pseudo-range be ρ _RD RNSS pseudo-range is ρ _RN Then, the RDSS pseudo-range of the visible GEO satellite and the RNSS pseudo-range equation of other visible satellites can be combined as follows:

knowing the pseudoranges of at least 4 satellites in view (at least two GEO satellites), four unknowns [ x, y, z, δt can be solved _u ],δt _u Is the receiver clock difference, equal to c (t _u -t _i )。

The linearized GNSS observation equation is expressed as follows:

Z＝GX _u +ξ；

wherein Z is the difference between the measured pseudo-range and the estimated value, the estimated value is obtained by bringing the approximate position and clock bias of the receiver into a pseudo-range equation, the measured value is a pseudo-range measured value acquired by the receiver, wherein the pseudo-range measured value of the satellite signal received by the RDSS module uses the RDSS pseudo-range measured value, G is an observation geometric matrix, u is the number of observation equations, X is an estimated state vector, three position components and the clock bias of the receiver are included, and xi is an observation noise vector. Wherein X may be represented as:

X _u ＝[x,y,z,δt _u ] ^T ；

according to the least squares algorithm, the estimate of X is:

X＝(G ^T G) ^-1 G ^T Z；

the pseudorange estimate residuals may be expressed as:

ω＝[In-G(G ^T G) ^-1 G ^T ]Z；

defining a statistical detection amount:

SSE＝ω ^T ω；

when no deception satellites exist and deception signals exist, SSEs exhibit different statistical properties, so that the SSEs can be used as a basis for detecting whether deception satellites exist in the current observance. According to the false alarm rate and the omission factor, the number of visible satellites can be calculated in advance to obtain a detection threshold; if the number of visible satellites involved in the calculation is n, then there are:

no fault assumption H0:

faulty hypothesis H1:

so that given a false alarm rate,

can be determined by the method A detection threshold T of SSE, i.e. a detection threshold of SSE:

T _SSE ＝σ ₀ T；

comparing the current SSE with a corresponding threshold T, if the SSE is less than the threshold, deeming that no spoofing exists, otherwise deeming that spoofing exists.

It will be appreciated that either the first pseudorange residual ω is calculated ₁ Or a second pseudo-range residual omega ₂ The same calculation method is adopted.

And the other visible satellites which are not stored in the target array are extracted as target satellites, and deception detection is carried out on the target satellites according to the reference satellites until the other visible satellites which are not stored in the target array are extracted, specifically:

obtaining the total number of GEO satellites and other satellites not yet stored in the target array,

when the total number is larger than or equal to a first preset value, judging whether the first number of the reference satellites is not smaller than a second preset value or not;

Specifically, in a preferred embodiment, the satellites in view include GEO satellites (stationary orbiting satellites) and other satellites (MEO in orbit satellites, LEO low orbit satellites, etc.), only GEO may be RDSS-enabled, e.g., if there are 6 satellites in view, only 2 GEO may be left, leaving 4 other satellites in view.

Illustratively, the first preset value is preset to be 5 and the second preset value is preset to be 4; therefore, when the total number is judged to be more than or equal to a first preset value (5), judging whether the first number of the reference satellites is not less than a second preset value (4);

If the first number m of the reference satellites is 4 or greater than 4, the first number m of the reference satellites is larger than or equal to a second preset value, only one other visible satellite is extracted as a target satellite when the other visible satellites are extracted from the other visible satellites which are not yet stored in the target array, and deception detection is carried out on the target satellite according to the reference satellites until the other visible satellites which are not yet stored in the target array are extracted;

if the first number m of reference satellites is 3, it indicates that only one other visible satellite cannot be extracted, and it is necessary to extract 2 satellites and calculate the simultaneous equations of the reference satellites.

Taking the difference value between the first number of the reference satellites and a first preset value as a first target number (2), extracting other visible satellites corresponding to the first target number (2) as target satellites, and performing deception detection on the target satellites according to the reference satellites; and when the second extraction is performed, repeatedly performing the following target satellite extraction operation until other visible satellites which are not stored in the target array are extracted:

specifically, the following target satellite extraction operations are repeatedly performed:

firstly, judging whether the number of target satellites without deception is equal to a target difference value; the target difference value is the difference value between the second preset value and the reference satellite;

The method can be divided into three judging cases, namely whether the number of target satellites without fraud is equal to a target difference value or not, namely whether a new reference combination is formed or not, whether the second extraction or the extraction process after no fraud combination (namely, whether 4 reference satellites are used as the reference combination of simultaneous equations) is found;

if the target satellite is equal to the target satellite, the target satellite without deception can be directly combined with each reference satellite to generate a new reference satellite combination, then one other visible satellite is extracted from other visible satellites which are not stored in the target array to serve as the target satellite, and deception detection is carried out on the target satellite according to the new reference satellite combination;

if the number of the target satellites which are not equal to and have no fraud is smaller than the target difference value, the method indicates that after new reference satellite combination is generated by new target satellites, no fraud combination taking 4 reference satellites as reference is not achieved yet, and the target satellites corresponding to the second target number need to be extracted to form a simultaneous equation with five satellites. Combining the target satellites without deception with each reference satellite to generate new reference satellite combinations, taking the difference value between the second number of the new reference satellite combinations and the first preset value as the second target number, extracting other visible satellites corresponding to the second target number as target satellites, and deceptively detecting the target satellites according to the new reference satellite combinations;

Illustratively, when the first number m of reference satellites is 2 and the number of target satellites for which no fraud is determined to be present is 1, the target difference is 4-2=2, the determination 1<2 is made that no fraud combination based on 4 is not reached, the difference between the second number of new reference satellite combinations and the first preset value is 5-3=2 as the second target number, and 2 target satellites need to be extracted to form a simultaneous equation with 5 satellites.

If the number of target satellites which are not equal to and have no fraud is larger than the target difference value, the method indicates that a plurality of target satellites have no fraud and can be combined with the original reference satellites to form 4 new reference satellites. However, it is possible that this time, the second extraction is performed, it is determined that a new reference satellite combination is not generated, then a new reference satellite combination is generated by extracting a number of target satellites corresponding to the target difference value and combining the target satellites with each reference satellite, and one other visible satellite is extracted from other visible satellites which are not stored in the target array as a target satellite, and spoofing detection is performed on the target satellite according to the new reference satellite combination;

if the extraction is not the second extraction but the subsequent multiple extraction, and it is determined that a new reference satellite combination has been generated, then only a single-satellite traversal is performed, that is, one other visible satellite is extracted from the other visible satellites that are not yet stored in the target array as a target satellite, and spoofing detection is performed on the target satellite according to the new reference satellite combination.

Schematically, on the combination without fraud, a single-star traversal refers to adding one other satellite which does not judge whether to have fraud or not at each time, calculating pseudo-range residual error together, if the added satellite does not exceed a threshold, indicating that the added satellite has no fraud, and if the added satellite exceeds the threshold, the added satellite has fraud, and finally, screening the spoofed condition of each satellite in a permutation and combination mode.

It will be appreciated that upon determining that the total number is less than a first predetermined value, then the GEO satellites or other satellites in view of the presence of fraud in the target array are directly output.

The least square RAIM detection deception requires the number of visible satellites, more than 5 can perform deception detection, and more than 6 can identify specific deception satellites. When a large number of satellites are deceptively rogue at the same time, a general least squares residual test method may treat a deceptive satellite signal as normal, and treat a normal satellite signal as an anomalous satellite that does not satisfy consistency.

Therefore, the invention can use the RDSS normal pseudo range provided by the GEO satellite as prior information and uses the normal satellite detected in the consistency detection as a reference to carry out a random least square residual error method.

As shown in fig. 4, assuming that m RDSS visible satellites (m > =2) are provided, if m <4, 5-m satellites are randomly selected from the remaining satellites each time to form a solution equation set, so as to obtain a solution SSE, if the SSE is greater than a threshold, it is determined that fraud exists in the 5-m satellites, whether several satellites contain fraud satellites can be obtained each time, and a specific fraud satellite can be determined by multiple loops. When m > =4, 4 satellites are taken as references, one satellite is selected from the rest satellites each time, an equation set is formed by the four satellites, SSE is calculated, and combinations exceeding the threshold can be directly screened out by assuming the detection threshold, so that the spoofed satellites are determined.

Aiming at the problem that the auxiliary detection algorithm is limited by RDSS precision and is easy to misjudge by directly using the RDSS calculated position information, the invention directly utilizes RDSS pseudo-range data for detection, and improves the reliability of the algorithm.

For step S6, in a preferred embodiment, the visible satellites determined to be deceptive in the above steps may be acquired in the target array, so that when outputting the visible satellites in the target array, it may be listed which GEO visible satellites or other visible satellites are deceptive.

According to the invention, the received RDSS pseudo range of the GEO satellite is taken as a reference, other visible satellite RNSS pseudo range data is added, and the group residual error is checked to find out the spoofed satellite, so that the spoofing identification capability of the traditional RAIM method is improved, a plurality of spoofed satellites can be effectively identified, and various positioning spoofing can be identified, so that each satellite can be accurately identified whether spoofing exists, and the spoofing detection accuracy is improved.

As shown in fig. 5, on the basis of the embodiments of the above-mentioned various RDSS-assisted receiver spoofing detection methods, the present invention correspondingly provides apparatus item embodiments;

It should be noted that the apparatus embodiments described above are merely illustrative, and the modules described as separate components may or may not be physically separate, and components shown as modules may or may not be physical modules, may be located in one place, or may be distributed over multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the embodiment of the device provided by the invention, the connection relation between the modules represents that the modules have communication connection, and can be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art will understand and implement the present invention without undue burden.

It will be clearly understood by those skilled in the art that, for convenience and brevity, the specific working process of the apparatus described above may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.

Based on the above embodiments of the various RDSS assisted receiver spoofing detection methods, the present invention correspondingly provides terminal equipment item embodiments.

An embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, where the processor executes the computer program to implement a RDSS-assisted receiver spoofing detection method according to any one of the method embodiments of the present invention.

The terminal equipment can be computing terminal equipment such as a desktop computer, a notebook computer, a palm computer, a cloud server and the like. The terminal device may include, but is not limited to, a processor, a memory.

The processor may be a central processing unit (Central Processing Unit, CPU), other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. The general purpose processor may be a microprocessor or the processor may be any conventional processor or the like, which is a control center of the terminal device, and which connects various parts of the entire terminal device using various interfaces and lines.

The memory may be used to store the computer program, and the processor may implement various functions of the terminal device by running or executing the computer program stored in the memory and invoking data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function, and the like; the storage data area may store data created according to the use of the cellular phone, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, memory, plug-in hard disk, smart Media Card (SMC), secure Digital (SD) Card, flash Card (Flash Card), at least one disk storage device, flash memory device, or other volatile solid state storage device.

While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.

Claims

1. A method for RDSS-assisted receiver spoofing detection comprising:

2. The RDSS-assisted receiver spoofing detection method of claim 1, wherein said calculating a pseudorange difference from corresponding RNSS pseudoranges and RDSS pseudoranges, based on a comparison of said pseudorange difference to a first predetermined test threshold range, storing GEO satellites whose pseudorange differences are not within said first predetermined test threshold range in said target array comprises:

D _i ＝Prn _i -Prd _i ；

3. The RDSS aided receiver spoofing detection method of claim 1, wherein said performing simultaneous equations on RDSS pseudoranges of a GEO visible satellite and RNSS pseudoranges of other visible satellites according to a least squares residual method, said performing a solution on said simultaneous equations to obtain a first pseudorange residual, comprises:

wherein, (x) _m ,y _m ,z _m ) Indicating the position of the mth satellite,RDSS pseudoranges representing mth satellite, +.>RNSS pseudo-range, δt, representing the (m+1) -th satellite _u Representing receiver clock skew;

Z＝GX _u +ξ；

X _u ＝[x,y,z,δt _u ] ^T ；

X _u ＝(G ^T G) ^-1 G ^T Z；

ω ₁ ＝[I _n -G(G ^T G) ^-1 G ^T ]Z；

4. A method for detecting fraud in an RDSS assisted receiver according to claim 3, wherein said extracting other satellites in view not yet stored in said target array as target satellites and performing fraud detection on the target satellites based on reference satellites until the other satellites in view not yet stored in said target array are extracted, comprises:

5. A RDSS assisted receiver spoofing detection method according to claim 4, wherein said calculating a statistical measure from said second pseudorange residuals comprises:

SSE＝ω ₂ ^T ω ₂

6. A method of RDSS assisted receiver spoofing detection in accordance with claim 1, further comprising:

7. An RDSS-assisted receiver spoofing detecting apparatus comprising: the system comprises a signal data receiving module, an ephemeris consistency checking module, a pseudo-range consistency checking module, a first deception detecting module, a second deception detecting module and a deception detecting result output module;

8. A terminal device comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, the processor implementing an RDSS-assisted receiver spoofing detection method as defined in any one of claims 1 to 6 when the computer program is executed.