CN103760571A - Vulnerability monitoring system and method for GPS based on influence factor characteristics - Google Patents

Vulnerability monitoring system and method for GPS based on influence factor characteristics Download PDF

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CN103760571A
CN103760571A CN201410052157.9A CN201410052157A CN103760571A CN 103760571 A CN103760571 A CN 103760571A CN 201410052157 A CN201410052157 A CN 201410052157A CN 103760571 A CN103760571 A CN 103760571A
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satellite
monitoring
fragility
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CN103760571B (en
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战兴群
赵欣
荆帅
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Shanghai Jiaotong University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/20—Integrity monitoring, fault detection or fault isolation of space segment
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/23—Testing, monitoring, correcting or calibrating of receiver elements

Abstract

The invention relates to the technical field of satellite navigation, in particular to a vulnerability monitoring system and method for a GPS based on influence factor characteristics. The system comprises a control calculation module, an evaluation calculation module, a space segment vulnerability simulation module, a software receiver module and a monitor station module. The system and method solve the technical problem that according to an existing satellite navigation system, the monitoring process of vulnerability influence factors is complex, and the quantitative judgment standard lacks, on the premise that visible calculation errors are not introduced, the monitoring efficiency of the vulnerability influence factors is greatly improved, and a systematic, rapid and accurate realization approach is provided for vulnerability monitoring and judgment of the global navigation satellite system.

Description

Fragility monitoring system and method based on influence factor feature for GPS
Technical field
What the present invention relates to is the system and method in a kind of satellite navigation field, specifically a kind of for GPS(Global Positioning System) fragility monitoring system and method based on influence factor feature.
Background technology
GLONASS (Global Navigation Satellite System) fragility refers to that GLONASS (Global Navigation Satellite System) service performance under all kinds of factor impacts lacks or the degree of decay, is the build-in attribute of system.Its intension refers to when all kinds of faults, disturbing factor occur, the affected degree of system and service quality.Its extension mainly comprises: the influence factors such as satellite failure inefficacy, inter-satellite link Communication Jamming, satellite-ground link Communication Jamming, atmosphere environment impact (ionosphere/troposphere), multipath effect, terminal fault.Along with GLONASS (Global Navigation Satellite System) being widely used of nearly all field such as military affairs, national economy, daily life worldwide, the mankind more and more rely on location, navigation and the time service service that GPS (Global Position System) provides.Therefore for all GPS (Global Position System), analyze its fragility degree, judge that can it provide and stablize service and become important subject.
Find by prior art documents, Saint Germain en Laye. writes articles GNSS Vulnerability and Mitigation Measures[C] IALA Recommendation R-1292012. " GPS (Global Position System) fragility and remission method ", a kind of fragility major influence factors of GPS (Global Position System) and the remission method of impact thereof have been proposed in literary composition, but this technology is complicated for particular vulnerability factor process, and there is no quantitative measurement criteria for classification, do not there is operability, therefore building effective fragility monitoring system has great importance for GLONASS (Global Navigation Satellite System) vulnerability assessment problem.
Summary of the invention
The present invention is directed to prior art above shortcomings, a kind of fragility monitoring system and method based on influence factor feature for GPS proposed, solved the observation process of existing satellite navigation system fragility influence factor complicated and lack the technical matters of quantitative criterion, do not introducing under the prerequisite of the visible error of calculation, greatly improve the monitoring efficiency of fragility influence factor, the fragility monitoring that makes GLONASS (Global Navigation Satellite System) and judgement have system, realize approach fast and accurately.
The present invention is achieved by the following technical solutions:
The present invention relates to a kind of fragility monitoring system based on influence factor feature for GPS, comprise: control computing module, evaluates calculation module, space segment fragility emulation module, software receiver module and monitoring station module, wherein: control computing module and be connected with space segment fragility emulation module and transmit fragility factor generation parameter, space segment fragility emulation module is respectively to monitoring station module transmission electronic concentration, Tropospheric Models parameter, ionospheric scintillation parameter and/or ionosphere model parameters, and to software receiver module transmission inter-satellite link distance measurement value, evaluates calculation module respectively with space segment fragility emulation module, monitoring station module is connected with control computing module, utilize various fragility factor simulated datas that space segment fragility emulation module and monitoring station module generate calculate assessment results and by result feedback to controlling computing module.
Described space segment fragility emulation module comprises: GPS inter-satellite link signal simulator, ionosphere and troposphere simulation unit, wherein: GPS inter-satellite link signal simulator is connected with evaluates calculation module and transmits pseudo-range measurements between star, ionosphere and troposphere simulation unit are connected with ionospheric scintillation monitoring means in the module of monitoring station and transmit ionosphere model parameters or electron concentration, ionospheric scintillation parameter, Tropospheric Models parameter.
Described monitoring station module comprises: the CORS being connected with software receiver module respectively (Continuous Operational Reference System the moves satnav service colligate system continuously) unit of standing, IGS (International GPS) server unit, four mould reference station receiver units and ionospheric scintillation monitoring means, wherein: unit, CORS station is to software receiver module output receiver observation information, IGS server unit is to software receiver module output satellite ephemeris and atmospheric environment file, four mould reference station receiver units are to software receiver module output pseudo-range measurements, signal power, carrier-to-noise ratio, navigation message and the elements of a fix, ionospheric scintillation monitoring means is to software receiver module output ionospheric scintillation monitoring information.
Described software receiver module comprises: the Satellite Autonomous Integrity Monitoring (SAIM being connected with evaluates calculation module respectively, Satellite Autonomous Integrity Monitoring) unit, receiver autonomous integrity monitoring (RAIM, Receiver Autonomous Integrity Monitoring) unit, positioning result computing unit, text detecting unit and carrier-to-noise ratio computing unit, atmosphere delay computing unit, wherein: Satellite Autonomous Integrity Monitoring unit is the integrity information at space segment to evaluates calculation module output satellite, receiver autonomous integrity monitoring unit is the integrity information at user side to evaluates calculation module output satellite, positioning result computing unit is to the actual location information of evaluates calculation module output receiver user, text detecting unit is to evaluates calculation module output text consistency detection result, carrier-to-noise ratio computing unit is to the actual carrier-to-noise ratio data that obtain of evaluates calculation module output, the propagated error that atmosphere delay computing unit brings to evaluates calculation module output atmosphere delay.
Described evaluates calculation module comprises: fragility comprehensive assessment unit and be attached thereto respectively the SAIM object information unit connecing, RAIM object information unit, positioning error assessment unit, the consistent assessment unit of text, Signal quality assessment unit, atmospheric environment assessment unit and fragility comprehensive assessment unit, wherein: fragility comprehensive assessment unit is the integrity information at space segment according to the satellite receiving, satellite is at the integrity information of user side, the actual location information of receiver user, text consistency detection result, the actual carrier-to-noise ratio data that obtain, the propagated error that atmosphere delay is brought calculates system vulnerability information.
The fragility monitoring method that the present invention relates to said system, comprises the following steps:
Step 1, fragility monitoring system start, and set the goal systems signal that needs monitoring on monitoring equipment, obtain the set M={x of all satellite-signals 1(t), x 2(t), x 3(t) ..., x n(t) }, and obtain the big or small N of initial sets, wherein: x i(t) be illustrated in dissimilar signal on selected frequency, N represents signal type sum.
Step 2, according to the system information of target frequency bands, from fragility monitoring system, obtain the information list of the satellite navigation signals of GPS;
Described system information refers to: the selected frequency of current system, comprises L1, L2, the L5 frequency of GPS.
Described information list comprises: current visible star information, current positioning accuracy information, current GPS relative positioning information (GDOP), current real-time navigation textual information, real-time navigation signal quality (C/No) information, real-time troposphere, ionosphere delay information, current RAIM/SAIM object information, receiver positioning error information.
Step 3, real-time navigation text is carried out to text compliance evaluation: monitoring from the real-time navigation text of fragility monitoring system actual measurement according to orbit information wherein, carry out the reckoning of current co-ordinates of satellite, the co-ordinates of satellite obtaining is calculated to result and contrasted from the co-ordinates of satellite in the Exact Forecast ephemeris of IGS server, obtain the deviate of current projected coordinate with the prediction coordinate of every satellite
Figure BDA0000466176320000031
wherein: x 0, y 0, z 0represent respectively the co-ordinates of satellite of extrapolating according to actual measurement navigation message; x, y, z represents the co-ordinates of satellite obtaining from IGS server unit Exact Forecast ephemeris; when deviate does not judge that over setting threshold navigation message is correct and perform step four, otherwise judge that abnormal being also further judged to be of navigation message system text occurred extremely or production cheating interference.Because production cheating interference can first cause the decline of receiver signal quality so that receiver losing lock just can complete deception, therefore want the Signal quality assessment of integrating step four determine the end be system text extremely or production cheating interference.
Step 4, Signal quality assessment: whether the minimum signal power that monitoring receives meets or exceeds ICD and specify numerical value, when being less than or equal to ICD, formulating numerical value and think and occur production deception, otherwise think that system text is abnormal, specifically comprise: monitor current visible star situation, analysis and prediction ephemeris visible satellite number, defend the similarities and differences of asterisk; For being denoted as healthy satellite-signal, monitoring receiver uninterruptedly
Figure BDA0000466176320000032
value, report
Figure BDA0000466176320000033
reduce or raise suddenly suddenly, and the situation that departs from periodic regularity value or theoretical value, adaptive algorithm adopted: by calculating within the scope of a detecting window
Figure BDA0000466176320000034
mean value, compare with the threshold value of setting, when mean value is less than threshold value, think that system text is abnormal, otherwise think and occur production deception.
Described relatively realizes by judgement formula, is specially: | mean (Z) | >|mean (Y) | during+2 σ (Y), assert to have to disturb to occur, wherein: Z represents within the scope of detecting window mean value, Y represents setting threshold, σ represents the standard deviation of threshold fluctuations.
Described threshold value is by the calculating of estimating
Figure BDA0000466176320000036
window both sides
Figure BDA0000466176320000037
noise is determined.
The mode of step 5, employing IONEX and two models couplings of Klobuchar is carried out the atmospheric environment assessment based on anomalous of the ionosphere, is specially: 2 times of conduct delay threshold values that setting Klobuchar postpones, when IONEX length of delay postpones to exceed delay threshold value, work as
Figure BDA0000466176320000038
time, judge that anomalous of the ionosphere occurs, otherwise think that ionosphere is normal, wherein: Δ IONEX represents the ionosphere delay calculating in real time according to IONEX model, Δ Klobuchar represents the ionosphere delay of calculating in real time according to Klobuchar model meter.
The assessment of step 6, integrity monitoring: software receiver module via satellite between observation data, utilize SAIM algorithm, in system, judge satellite failure situation, and obtain the satellite information of current abnormal work, utilize RAIM algorithm judgement satellite channel failure condition simultaneously, and obtain the channel information of current measurement value mistake.
Step 7, the monitoring of receiver positioning error: software receiver module obtains current positioning error and compares with setting threshold, when current positioning error does not surpass setting threshold, judge that positioning error judges without fragility event in tolerance interval, otherwise judge that positioning error is excessive, certainly there is fragility influence factor in judgement, last software receiver module generates positioning error result according to comparative result.
Described positioning error result comprises: satellite visibility degree of ramification Δ n, and navigation message track deviation value | Δ p|, carrier-to-noise ratio deviate ionosphere IONEX model and Klobuchar model ratio r ion, integrity monitoring result and positioning error measured value.
Step 8, the satellite visibility that step 3 is obtained to step 7, navigation message, signal quality, atmospheric environment, integrity monitoring and positioning error result, input to fragility monitoring system, obtains system vulnerability information.
Described fragility monitoring system progressively compares to draw Current GPS fragility whether conclusion according to thresholding, and calculates current fragile degree index, realizes determining of fragility factor after each self-corresponding weight is weighted.
Technique effect
Compared with prior art, first the present invention sets the echo signal that needs detection on monitoring equipment, press each segmentation that gps system forms, satellite-signal is classified, satellite-signal to be detected is carried out to the monitoring of fragility influence factor with classified known satellite signal respectively, finally obtain the judged result of fragility influence factor.
The present invention carries out the monitoring of fragility influence factor to satellite navigation signals, to judge fast the fragility situation of different satellite navigation signals.This monitoring system is based on satellite navigation system each several part fragility influence factor, set respectively fragility thresholding, and each step of implementing has quantitative measurement criteria for classification, do not introducing under the prerequisite of the visible error of calculation, greatly improve monitoring efficiency and the systematicness of each influence factor of fragility, make the fragility monitoring of GLONASS (Global Navigation Satellite System) have with judgement the approach that realizes fast and accurately.
Accompanying drawing explanation
Fig. 1 is fragility monitoring system schematic diagram of the present invention.
Fig. 2 is that fragility factor affects interpretation of result figure.
Fig. 3 is fragility influence factor assessment algorithm process flow diagram.
Fig. 4 is that many satellites ionospheric model postpones and contrast ratio schematic diagram.
Fig. 5 is carrier-to-noise ratio theoretical value is set and actual observed value contrast schematic diagram.
Embodiment
Below embodiments of the invention are elaborated, the present embodiment is implemented take technical solution of the present invention under prerequisite, provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.
Embodiment 1
As shown in Figure 1, the fragility monitoring system that the present embodiment relates to, comprise: control computing module, evaluates calculation module, space segment fragility emulation module, software receiver module and monitoring station module, wherein: control computing module and be connected with space segment fragility emulation module and transmit fragility factor generation parameter, space segment fragility emulation module is respectively to monitoring station module transmission electronic concentration, Tropospheric Models parameter, ionospheric scintillation parameter and/or ionosphere model parameters, and to software receiver module transmission inter-satellite link distance measurement value, evaluates calculation module respectively with space segment fragility emulation module, monitoring station module is connected with control computing module, utilize various fragility factor simulated datas that space segment fragility emulation module and monitoring station module generate calculate assessment results and by result feedback to controlling computing module.
The built-in Comprehensive Control server unit of described control computing module.
Described space segment fragility emulation module comprises: GPS inter-satellite link signal simulator, ionosphere and troposphere simulation unit, wherein: GPS inter-satellite link signal simulator is connected with Satellite Autonomous Integrity Monitoring unit in evaluates calculation module and transmits pseudo-range measurements between star, ionosphere and troposphere simulation unit are connected with ionospheric scintillation monitoring means in the module of monitoring station and transmit ionosphere model parameters or electron concentration, ionospheric scintillation parameter, Tropospheric Models parameter.
Described monitoring station module comprises: the unit, CORS station being connected with corresponding unit in software receiver module respectively, IGS server unit, four mould reference station receiver units and ionospheric scintillation monitoring means, wherein: unit, CORS station is connected with positioning result computing unit with receiver autonomous integrity monitoring unit and transmits receiver observation information, IGS server unit is connected with text detecting unit and transmitting satellite ephemeris and atmospheric environment file, four mould reference station receiver units are connected and transmit pseudo-range measurements with carrier-to-noise ratio computing unit, signal power, carrier-to-noise ratio, navigation message and the elements of a fix, ionospheric scintillation monitoring means is connected with atmosphere delay computing unit and transmits ionospheric scintillation monitoring information.
Described software receiver module comprises: the Satellite Autonomous Integrity Monitoring unit being connected with each corresponding unit in evaluates calculation module respectively, receiver autonomous integrity monitoring unit, positioning result computing unit, text detecting unit and carrier-to-noise ratio computing unit, atmosphere delay computing unit, wherein: Satellite Autonomous Integrity Monitoring unit be connected with SAIM object information unit and transmitting satellite at the integrity information of space segment, receiver autonomous integrity monitoring unit be connected with RAIM object information unit and transmitting satellite at the integrity information of user side, positioning result computing unit is connected with positioning error assessment unit and the actual location information of transmission user receiver, text detecting unit assessment unit consistent with text is connected and transmitting text consistency detection result, carrier-to-noise ratio computing unit is connected with Signal quality assessment unit and transmits the actual carrier-to-noise ratio data that obtain, atmosphere delay computing unit is connected with atmospheric environment assessment unit and transmits the propagated error that atmosphere delay is brought.
Described evaluates calculation module comprises: fragility comprehensive assessment unit and be attached thereto respectively the SAIM object information unit connecing, RAIM object information unit, positioning error assessment unit, the consistent assessment unit of text, Signal quality assessment unit, atmospheric environment assessment unit and fragility comprehensive assessment unit, wherein: fragility comprehensive assessment unit is the integrity information at space segment according to the satellite receiving, satellite is at the integrity information of user side, the actual location information of receiver user, text consistency detection result, the actual carrier-to-noise ratio data that obtain, the propagated error that atmosphere delay is brought calculates GNSS vulnerability information.
The present embodiment carries out the judgement of fragility influence factor according to said system, specifically comprise following implementation condition: design satellite-signal x to be detected 1(t) be operated in L1 frequency range x 1(t) the pseudo-random code code length L of signal is 1023, signal spreading rate f cfor 1.023MHz, navigation data speed f dfor 50Hz.The a lot of because have of fragility can be caused, current the signal fault that anomalous of the ionosphere and a satellite have occurred might as well be supposed here.
The present embodiment said system, specifically realizes fragility by following steps and monitors:
Step 1: system starts, on monitoring equipment, setting the target frequency bands that need to detect is L1, obtains being positioned at the set M={x of all satellite-signals in this frequency range 1(t), GPS CA, GPS L1P (Y), GPS L1C}, and obtain the big or small N=4 of initial sets;
Step 2: according to the system information of target frequency bands, the information list of the satellite navigation signals of the L1 frequency range of acquisition gps system;
Described information list comprises: current visible star information, current positioning accuracy information, current GPS relative positioning information (GDOP), current real-time navigation textual information, real-time navigation signal quality (C/No) information, real-time troposphere, ionosphere delay information, current RAIM/SAIM object information, receiver positioning error information.
Step 3, real-time navigation text is carried out to text compliance evaluation, monitoring is from the real-time navigation text of fragility monitoring system actual measurement, according to orbit information wherein, carry out the reckoning of current co-ordinates of satellite, the co-ordinates of satellite obtaining is calculated to result and contrasted from the co-ordinates of satellite in the Exact Forecast ephemeris of IGS, obtain the deviate of current projected coordinate with the prediction coordinate of every satellite
Figure BDA0000466176320000061
wherein: x 0, y 0, z 0the co-ordinates of satellite that expression is extrapolated according to actual measurement navigation message, x, y, z represents the co-ordinates of satellite obtaining from IGS Exact Forecast ephemeris, this deviate does not surpass setting threshold and judges that navigation message is correct.Otherwise judge that navigation message is abnormal, need further judgement system text to occur extremely or production cheating interference actually.
Step 4, Signal quality assessment, whether the minimum signal power that monitoring receives meets or exceeds the numerical value of the upper appointment of ICD;
Monitor current visible star situation, analysis and prediction ephemeris visible satellite number, defend the similarities and differences of asterisk; For being denoted as healthy satellite-signal, monitoring receiver uninterruptedly
Figure BDA0000466176320000062
value, report
Figure BDA0000466176320000063
reduce or raise suddenly suddenly, and the situation that departs from periodic regularity value or theoretical value, adaptive algorithm adopted: by calculating within the scope of a detecting window
Figure BDA0000466176320000064
mean value, compare with the threshold value of setting, this threshold value is by the calculating of estimating window both sides
Figure BDA0000466176320000066
noise is determined.Judgement formula: | mean (Z) | >|mean (Y) | during+2 σ (Y), assert to have to disturb to occur.Code-the carrier wave of monitoring signal in each frequency range is dispersed the numerical value whether (code-carrier divergence) stipulates lower than ICD in time second at 100-7200; Whether the military code in monitoring L1 frequency range and the group's differential delay between the civil signal in other frequency range be lower than the numerical value of stipulating; Whether the degree of stability of the differential offset (differential bias) of monitoring L1 and L2 frequency range is in specialized range; According to periodic C/No carrier-to-noise ratio assessment signal interference problem, the carrier-to-noise ratio data that need historical record, and when user does not have log history carrier-to-noise ratio situation, can utilize theoretical C/No carrier-to-noise ratio to judge actual carrier-to-noise ratio abnormal conditions as threshold value, realize interference detection.
Utilize the observation data of this fragility monitoring system, with the carrier-to-noise ratio of the PRN12 satellite of on January 14th, 2013 observation, be recorded as example, describe.
Utilizing the computing formula of carrier-to-noise ratio theoretical value, according to actual reference station receiver observed case, the parameter in formula arranged---receiver is processed loss: 2dB; Receiver noise temperature: 290K; Antenna noise temperature: 190K; Atmospheric loss V parameter: 0.125;
Receiver antenna gain is calculated as follows: Crv=-5+15.5*sinEL, wherein:, EL is satellite elevation angle.
Lower limit compensation making: ± 1dB in theory; Known reference station receiver coordinate: [2840948,4659985,3289597]; Calculate the Fast Prediction ephemeris file of co-ordinates of satellite: igr17231.sp3; The carrier-to-noise ratio curve that the bound curve of carrier-to-noise ratio theory and actual reference station receiver obtain is substantially identical, illustrates that the setting of theoretical carrier-to-noise ratio parameter tallies with the actual situation.In Fig. 4, the PRN12 satellite carrier-to-noise ratio data time of demonstration be gps time from 32500s to 42500s, i.e. local time 17:01:40 to 19:48:20.During gps time 40000s to 42500s, there is fast-descending in actual carrier-to-noise ratio, and a little less than the lower limit of the theoretical curve of setting, reference station antenna may occur blocking to this moment satellite direction or the situation of multipath.Process continuously the reference station GPS L1/L2 of 10 days, the carrier-to-noise ratio data of BeiDou B1/B2, the cyclical variation of carrier-to-noise ratio as shown in the figure.
Carrier-to-noise ratio to above-noted
Figure BDA0000466176320000071
carry out data analysis, can find:
Figure BDA0000466176320000072
mean difference be 0.6426dB, standard deviation is 0.7028dB, analysis result shows,
Figure BDA0000466176320000073
periodic regularity is very obvious, and the carrier-to-noise ratio difference between two days is also little, after setting threshold, and can be for the timely discovery to abnormal signal situation.During setting threshold, the uncertain factors such as variation of weather need to be considered herein, therefore some nargin should be stayed, the standard deviation of 2 times or mean difference conduct variation range is proper.
The assessment of step 5, ionosphere delay, according to ionosphere delay model and forecast ephemeris, is monitored in conjunction with reference station observation data.The mode that adopts two models couplings, wherein IONEX length of delay is slightly larger than the Klobuchar corrective delay, and the error amount ratio that the former obtains than the latter is 1.2.2 times that set that Klobuchar postpones as threshold value, when IONEX length of delay or other real-time models postpone to exceed this threshold value, judges that anomalous of the ionosphere occurs;
Step 6, integrity monitoring assessment: observation data via satellite, utilize SAIM algorithm, in system, judge satellite failure situation, obtain current which satellite and self occurred extremely; By receiver observation data, utilize RAIM algorithm, from receiver angle judgement satellite channel failure condition, the measured value that obtains current which passage is wrong.
Utilize SAIM algorithm, from NASA official website, download the RINEX navigate file of 21:21 on November 22nd, 2011, file is called brdc3270.11n, calculates the satellite position of ephemeris prediction, and between the satellite position of ephemeris prediction and star, the mean value of bidirectional ranging value sum is made difference as real track residual error.Track residual error does not surpass corresponding minimum detectable deviation, illustrates and there is no mistake; Otherwise, fault has been described.
Step 7, the monitoring of receiver positioning error, positioning error does not surpass setting threshold, judges that positioning error is in tolerance interval, if surpassed setting threshold, judges that positioning error is excessive, can not accept.
Step 8, the satellite visibility that step 3 is obtained to step 7, navigation message, signal quality, atmospheric environment, integrity monitoring and positioning error result, be input to fragility monitoring system, these results comprise following parameter: navigation message track deviation value | Δ p|, carrier-to-noise ratio deviate
Figure BDA0000466176320000081
ionosphere IONEX model and Klobuchar model ratio r ionintegrity monitoring result and positioning error measured value, fragility monitoring system is progressively checked and is calculated current GNSS fragility whether conclusion according to the thresholding of the various piece being obtained by prior imformation, go out side by side specifically what factor and cause the fragile degree index of current fragility and fragility, and realize influence factor and judge.In this example, can obtain navigation message track deviation value | Δ p| and carrier-to-noise ratio deviate
Figure BDA0000466176320000082
do not surpass thresholding, ionosphere IONEX model and Klobuchar model ratio r ionsurpass thresholding, integrity monitoring goes out the abnormal and positioning error of a satellite-signal over the result of threshold value.Therefore can be easy to obtain the signal fault that current fragility influence factor is anomalous of the ionosphere and a satellite, and comprehensively ionosphere IONEX model and Klobuchar model ratio r ionand positioning error is calculated current fragile degree index over the size of threshold value.
Carry out again the hypothesis judgement of other factors: suppose the current occlusion interfere that occurred, can find the carrier-to-noise ratio deviate of all satellites
Figure BDA0000466176320000083
the abnormal measured value that even can not get carrier-to-noise ratio, it is a lot of that positioning error surpasses threshold value, be easy to obtain occurring the conclusion of occlusion interfere, and fragile degree index is quite high.Supposing current is that satellite message has occurred extremely, so navigation message track deviation value | Δ p| can surpass thresholding, and can obtain is the abnormal conclusion of text.With the abnormal situation comparing class of text seemingly, production cheating interference also can cause navigation message track deviation value | Δ p| surpasses thresholding, but cheating interference also can cause simultaneously the short time or lasting carrier-to-noise ratio abnormal, can compare by making an uproar deviate like this
Figure BDA0000466176320000084
whether have situation over threshold value to determine the end is the abnormal or production cheating interference of system text.What suppose current generation is that multipath disturbs or deceiving jamming again, comprises so carrier-to-noise ratio deviate
Figure BDA0000466176320000085
ionosphere IONEX model and Klobuchar model ratio r ionin interior factor, can not surpass threshold value, integrity monitoring result is also normal, only has positioning error can surpass thresholding, and now just can judge current fragility influence factor according to the thought of exclusive method is multipath effect or deceiving jamming.
The fragility influence factor monitoring method of the present embodiment, compares existing subitem technical monitoring method, is a kind of fragility monitoring means of system, and the fragility separation coefficient error obtaining is little a lot.

Claims (10)

1. the fragility monitoring system based on influence factor feature for GPS, it is characterized in that, comprise: control computing module, evaluates calculation module, space segment fragility emulation module, software receiver module and monitoring station module, wherein: control computing module and be connected with space segment fragility emulation module and transmit fragility factor generation parameter, space segment fragility emulation module is respectively to monitoring station module transmission electronic concentration, Tropospheric Models parameter, ionospheric scintillation parameter and/or ionosphere model parameters, and to software receiver module transmission inter-satellite link distance measurement value, evaluates calculation module respectively with space segment fragility emulation module, monitoring station module is connected with control computing module, utilize various fragility factor simulated datas that space segment fragility emulation module and monitoring station module generate calculate assessment results and by result feedback to controlling computing module.
2. system according to claim 1, it is characterized in that, described space segment fragility emulation module comprises: GPS inter-satellite link signal simulator, ionosphere and troposphere simulation unit, wherein: GPS inter-satellite link signal simulator is connected with evaluates calculation module and transmits pseudo-range measurements between star, ionosphere and troposphere simulation unit are connected with ionospheric scintillation monitoring means in the module of monitoring station and transmit ionosphere model parameters or electron concentration, ionospheric scintillation parameter, Tropospheric Models parameter.
3. system according to claim 1, it is characterized in that, described monitoring station module comprises: the unit, CORS station being connected with software receiver module respectively, IGS server unit, four mould reference station receiver units and ionospheric scintillation monitoring means, wherein: unit, CORS station is to software receiver module output receiver observation information, IGS server unit is to software receiver module output satellite ephemeris and atmospheric environment file, four mould reference station receiver units are to software receiver module output pseudo-range measurements, signal power, carrier-to-noise ratio, navigation message and the elements of a fix, ionospheric scintillation monitoring means is to software receiver module output ionospheric scintillation monitoring information.
4. system according to claim 1, it is characterized in that, described software receiver module comprises: the Satellite Autonomous Integrity Monitoring unit being connected with evaluates calculation module respectively, receiver autonomous integrity monitoring unit, positioning result computing unit, text detecting unit and carrier-to-noise ratio computing unit, atmosphere delay computing unit, wherein: Satellite Autonomous Integrity Monitoring unit is the integrity information at space segment to evaluates calculation module output satellite, receiver autonomous integrity monitoring unit is the integrity information at user side to evaluates calculation module output satellite, positioning result computing unit is to the actual location information of evaluates calculation module output receiver user, text detecting unit is to evaluates calculation module output text consistency detection result, carrier-to-noise ratio computing unit is to the actual carrier-to-noise ratio data that obtain of evaluates calculation module output, the propagated error that atmosphere delay computing unit brings to evaluates calculation module output atmosphere delay.
5. system according to claim 1, it is characterized in that, described evaluates calculation module comprises: fragility comprehensive assessment unit and be attached thereto respectively the SAIM object information unit connecing, RAIM object information unit, positioning error assessment unit, the consistent assessment unit of text, Signal quality assessment unit, atmospheric environment assessment unit and fragility comprehensive assessment unit, wherein: fragility comprehensive assessment unit is the integrity information at space segment according to the satellite receiving, satellite is at the integrity information of user side, the actual location information of receiver user, text consistency detection result, the actual carrier-to-noise ratio data that obtain, the propagated error that atmosphere delay is brought calculates system vulnerability information.
6. according to a fragility monitoring method for system described in above-mentioned arbitrary claim, it is characterized in that, comprise the following steps:
Step 1, fragility monitoring system start, and set the goal systems signal that needs monitoring on monitoring equipment, obtain the set M={x of all satellite-signals 1t, x 2t, x 3t ..., x n(t) }, and obtain the big or small N of initial sets, wherein: x i(t) be illustrated in dissimilar signal on selected frequency, N represents signal type sum.
Step 2, according to the system information of target frequency bands, from fragility monitoring system, obtain the information list of the satellite navigation signals of GPS;
Step 3, real-time navigation text is carried out to text compliance evaluation: monitoring from the real-time navigation text of fragility monitoring system actual measurement according to orbit information wherein, carry out the reckoning of current co-ordinates of satellite, the co-ordinates of satellite obtaining is calculated to result and contrasted from the co-ordinates of satellite in the Exact Forecast ephemeris of IGS server, obtain the deviate of current projected coordinate with the prediction coordinate of every satellite
Figure FDA0000466176310000021
wherein: x 0, y 0, z 0represent respectively the co-ordinates of satellite of extrapolating according to actual measurement navigation message; x, y, z represents the co-ordinates of satellite obtaining from IGS server unit Exact Forecast ephemeris; when deviate does not judge that over setting threshold navigation message is correct and perform step four, otherwise judge that abnormal being also further judged to be of navigation message system text occurred extremely or production cheating interference.Because production cheating interference can first cause the decline of receiver signal quality so that receiver losing lock just can complete deception, therefore want the Signal quality assessment of integrating step four determine the end be system text extremely or production cheating interference.
Step 4, Signal quality assessment: whether the minimum signal power that receives of monitoring meets or exceeds ICD and specify numerical value, formulate numerical value and think and occur production deception when being less than or equal to ICD, otherwise think that system text is abnormal.
The mode of step 5, employing IONEX and two models couplings of Klobuchar is carried out the atmospheric environment assessment based on anomalous of the ionosphere, is specially: 2 times of conduct delay threshold values that setting Klobuchar postpones, when IONEX length of delay postpones to exceed delay threshold value, work as
Figure FDA0000466176310000022
time, judge that anomalous of the ionosphere occurs, otherwise think that ionosphere is normal, wherein: Δ IONEX represents the ionosphere delay calculating in real time according to IONEX model, Δ Klobuchar represents the ionosphere delay of calculating in real time according to Klobuchar model meter.
The assessment of step 6, integrity monitoring: software receiver module via satellite between observation data, utilize SAIM algorithm, in system, judge satellite failure situation, and obtain the satellite information of current abnormal work, utilize RAIM algorithm judgement satellite channel failure condition simultaneously, and obtain the channel information of current measurement value mistake.
Step 7, the monitoring of receiver positioning error: software receiver module obtains current positioning error and compares with setting threshold, when current positioning error does not surpass setting threshold, judge that positioning error judges without fragility event in tolerance interval, otherwise judge that positioning error is excessive, certainly there is fragility influence factor in judgement, last software receiver module generates positioning error result according to comparative result.
Step 8, the satellite visibility that step 3 is obtained to step 7, navigation message, signal quality, atmospheric environment, integrity monitoring and positioning error result, input to fragility monitoring system, obtains system vulnerability information.
7. method according to claim 6, is characterized in that, described positioning error result comprises: satellite visibility degree of ramification Δ n, and navigation message track deviation value | Δ p|, carrier-to-noise ratio deviate
Figure FDA0000466176310000031
ionosphere IONEX model and Klobuchar model ratio r ion, integrity monitoring result and positioning error measured value.
8. method according to claim 6, is characterized in that, described step 4 specifically refers to: monitor current visible star situation, analysis and prediction ephemeris visible satellite number, defend the similarities and differences of asterisk; For being denoted as healthy satellite-signal, monitoring receiver uninterruptedly
Figure FDA0000466176310000033
value, report
Figure FDA0000466176310000034
reduce or raise suddenly suddenly, and the situation that departs from periodic regularity value or theoretical value, adaptive algorithm adopted: by calculating within the scope of a detecting window
Figure FDA0000466176310000035
mean value, compare with the threshold value of setting, when mean value is less than threshold value, think that system text is abnormal, otherwise think and occur production deception.
9. method according to claim 6, it is characterized in that, described fragility monitoring system progressively compares to draw Current GPS fragility whether conclusion according to thresholding, and calculates current fragile degree index, realizes determining of fragility factor after each self-corresponding weight is weighted.
10. according to the method described in claim 6 or 8, it is characterized in that, described relatively realizes by judgement formula, is specially: | mean (Z) | >|mean (Y) | during+2 σ (Y), assert to have to disturb to occur, wherein: Z represents within the scope of detecting window
Figure FDA0000466176310000036
mean value, Y represents setting threshold, σ represents the standard deviation of threshold fluctuations.
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