CN102540222B - Threshold determining apparatus and method - Google Patents
Threshold determining apparatus and method Download PDFInfo
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- CN102540222B CN102540222B CN201110364772.XA CN201110364772A CN102540222B CN 102540222 B CN102540222 B CN 102540222B CN 201110364772 A CN201110364772 A CN 201110364772A CN 102540222 B CN102540222 B CN 102540222B
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Abstract
The invention relates to a threshold determining apparatus, method, and procedure, used for selecting ephemeris data sent by the GPS satellite among several GPS satellites and making sure that the threshold determining apparatus of the GPS satellite upon the detecting position can obtain the threshold capable of meeting the integrity and sustainability of the position-detecting system. The threshold determining part, based on the maximum allowed detecting probability of failure and the maximum allowed fault alarm probability, is used for selecting the threshold of the GPS satellite. As it is based on the maximum allowed detecting probability of failure, the integrity of the position-detecting system can be satisfied. As it is based on the maximum allowed fault alarm probability, the sustainability of the position-detecting system can be satisfied.
Description
Technical field
The present invention relates to determine for defending from multiple GPS (Global Positioning System, global positioning system)
It is selected to provide threshold determining apparatus of the normal ephemeris data using the threshold value of the gps satellite on location in star, and
It is related to determine for being selected to provide normal ephemeris data to use the gps satellite on location from multiple gps satellites
Threshold value Threshold and program.
Background technology
In the landing system of aircraft, DGPS (the Differential GPS of the narrow and small overlay area of near airports：Difference
GPS) it is referred to as GBAS, by ICAO (International Civil Aviation Organization：International civil aviation
Tissue) determine standard and suggestion (SARPs：Standardsand Recommended Practices, standard and suggestion are arranged
Apply), in the standard and suggestion, it is stipulated that precision, integrity, availability and persistence etc. are required.
In the system of the GBAS, received from GPS by the ground installations (the hereinafter referred to as GBAS grounds station) of DGPS
The location signal of satellite simultaneously determines which the distance between with satellite, generates GBAS update informations based on the measured value, and uses VHF
The data link of (Very High Frequency, very high frequency(VHF)) band sends GBAS update informations to aircraft (GBAS user).
In the system of the GBAS, in real orbital position and the track letter by being broadcasted by gps satellite of gps satellite
In the case of there is larger difference between the orbital position for ceasing and calculating, landing guidance is carried out when the broadcast from the satellite is used
When, it is possible to accident can be caused.In order to avoid the state of affairs, the system of GBAS have monitor, the monitor is to by by GPS
The size of the error included by the orbit information of satellite broadcasting and the orbital position that calculates is evaluated.
Here, gps satellite sends the location signal needed to calculate the position of aircraft, and the GBAS grounds station is using next
From the location signal of gps satellite, in order to improve aircraft navigation precision and safety and generate GBAS update informations.Also, fly
Machine has the receiver for receiving the location signal from gps satellite and the receiving device for receiving GBAS update informations.
As described above, when used in airmanship in the case of the location signal of gps satellite, to aircraft position
Calculating uses the satellite position calculated according to the ephemeris data (ephemeris) as the orbit information broadcasted by gps satellite.Star
Ephemeris data is typically each two hour and updates once left and right, and the situation of the orbit information of mistake is broadcast when in the renewal
Under, the location error of aircraft can increase, it is possible to safe navigation cannot be guaranteed.
Accordingly, as the decision method that can the error and orbit information of detection orbit information use, in non-patent text
Following methods are disclosed in offering 1：According to the initial value of the orbital elements of ephemeris data, using GPS Interface
Algorithm described in Specification IS-GPS-200E calculates the satellite described by earth fixed coordinate system in temporal sequence
Three-dimensional position, to what is calculated according to new and old ephemeris (ephemeris data after renewal and the ephemeris data before updating)
Two kinds of three-dimensional positions are compared, in the case where the difference of position exceedes predetermined threshold, the ephemeris number after being judged as being updated
Cannot be used according to error greatly.
In addition, being also shown for following methods in patent documentation 1～3：Quality and predetermined threshold value to observing data is entered
Row relatively come determine whether to abandon to observe the method for data and according to the difference of the estimated value and detected value of Doppler shift whether
Determine whether more than or equal to threshold value by ephemeris data be set to invalid method etc., and to basis from the data of satellite
The value and predetermined threshold value for obtaining is compared to determine whether the method using the data from satellite.
Citation
Non-patent literature
Non-patent literature 1：SamPullen, outer 5, " Ephemeris Protection Level Equations and
Monitor Algorithms for GBAS ", ION GPS 2001, September 11-14 day calendar year 2001.
Patent documentation
Patent documentation 1：Japanese Patent Laid-Open 2000-275320 publication；
Patent documentation 2：Japanese Patent Laid-Open 2003-21672 publication；
Patent documentation 3：Japanese Patent Laid-Open 2009-68927 publication.
The content of the invention
When setting determines the threshold value that can the data from satellite use, the permission for the data from satellite is missed
Difference (the permission model of the error of the position of the satellite of the positional information and reality of the satellite calculated using the data from satellite
Enclose) set bigger, the error included by the location data of the aircraft calculated using the data from the satellite is possible to bigger,
The safety of aircraft navigation is lower.
On the other hand, due to setting less by allowable error, it is judged to use the probability of the data from satellite to become
Must be higher, therefore, it is possible to use the data deficiencies on the location of aircraft, it is impossible to which the probability for carrying out location is uprised.
Thus, can the setting that use the decision threshold of the data (ephemeris data) from satellite be for making Aircraft
Capable safety (viability of location system) and location (persistence of location system) while the important process set up, but
It is the establishing method that threshold value is not shown in any one of above-mentioned non-patent literature 1 and above-mentioned patent documentation 1～3.
The present invention its object is to provide the threshold determining apparatus that can solve the problem that the problems referred to above, Threshold and journey
Sequence.
Means for solving the problem
The present invention is completed to solve the above problems, the threshold determining apparatus of a mode of the present invention, institute
State threshold determining apparatus to determine for selecting transmission to defend using the GPS of the ephemeris data on location from multiple gps satellites
The threshold value of star, it is characterised in that with threshold value determining section, the threshold value determining section is based on the maximum allowable detection failure being set
Probability and maximum allowable false alarm probability are determining for selecting the threshold value of the gps satellite.
In addition, the Threshold of a mode based on the present invention, the Threshold is determined for from many
Transmission is selected to be used in the threshold value of the gps satellite of the ephemeris data on location in individual gps satellite, it is characterised in that
Step is determined including threshold value, the threshold value determines step based on the maximum allowable detection probability of failure being set and most
It is big to allow false alarm determine the probability to be used to select the threshold value of the gps satellite.
In addition, the program of a mode based on the present invention, for making the computer as threshold determining apparatus perform threshold
Value determines step, wherein the threshold determining apparatus are determined for selecting transmission to be used in location from multiple gps satellites
Ephemeris data gps satellite threshold value,
The threshold value determines step based on the maximum allowable detection probability of failure and maximum allowable false alarm probability being set
It is determined that the threshold value for selecting the gps satellite.
The effect of invention
In accordance with the invention it is possible to be met the threshold of the persistence of the viability and location system of location system simultaneously
Value.
Description of the drawings
Fig. 1 is the block diagram of the schematic configuration example for illustrating the GBAS grounds station in an embodiment of the invention；
Fig. 2 is to illustrate flow chart that threshold value in this embodiment determines the process step of computer threshold value；
Fig. 3 is each of the example of the position relationship for illustrating the GBAS grounds station (the benchmark station), gps satellite and aircraft
The explanatory diagram of variable；
Fig. 4 is to be shown with the position of gps satellite obtained from new ephemeris, defended using GPS obtained from old ephemeris
The explanatory diagram of each variable of the relation of the position of star and the actual location of gps satellite；
Fig. 5 be the embodiment is shown in the distribution of the scale of three-dimensional error that is standardized and being capable of given threshold
The relation explanatory diagram of scope.
Specific embodiment
Below, refer to the attached drawing is illustrated to embodiments of the present invention.Additionally, the range of application of the present invention is not limited to
The GBAS grounds station illustrated in present embodiment, but can apply and receive each of ephemeris data from multiple gps satellites
Plant in the GPS device of various kinds.
Fig. 1 is the block diagram of the schematic configuration example for illustrating the GBAS grounds station in an embodiment of the invention.At this
In figure, the GBAS grounds station 1 have the benchmark station 100, gps satellite select computer 200, threshold value determine computer 300, and
VHF datacast apparatus 400 comprising antenna.The benchmark station 100 has GPS receiver antenna 110 and GPS receiver equipment
200.Threshold value determine computer 300 have integrity (integrity) threshold calculations portion 310, persistence threshold calculations portion 320,
And threshold value determining section 330.
The GBAS grounds station 1 is arranged in airport space or near airports are receiving from gps satellite 801～805
Wireless signal, and send the data of amendment when carrying out location comprising the aircraft 901 as GBAS user (GBAS amendment letters
Breath) wireless signal.The benchmark station 100, gps satellite is selected computer 200, threshold value and determines computer 300, and VHF data
Broadcasting equipment 400 can be arranged in identical building and its periphery, it is also possible in multiple buildings and its periphery point
Open up and put.
Additionally, the range of application of the present invention is not limited to the situation that the number of the gps satellite shown in Fig. 1 is 5.Also can be by
The present invention is applied in various GPS devices, and the GPS device receives ephemeris data from multiple gps satellites, based on new and old star
Ephemeris data (ephemeris data before renewal and the ephemeris data after updating) and threshold value are selecting the gps satellite of location.
In addition, aircraft unlimited number is in 1 shown in Fig. 1, or multiple stage.
GPS receiver antenna 110 receives from gps satellite 801～805 wireless signal (gps signal) for sending, and will be connect
The wireless signal of receipts is exported to GPS receiver equipment 120.GPS receiver with antenna 110 from gps satellite 801～805 receive it is wireless
Signal packet is containing the ephemeris data as the orbit information broadcasted from gps satellite.
GPS 120 is demodulated to the wireless signal received by GPS receiver antenna 110 etc. and to process and extract number
According to being sent to gps satellite and select computer 200.
Gps satellite select with computer 200 select from multiple gps satellites 801～805 four it is used above in aircraft
Gps satellite on 901 locations, and generate for the reinforcement information of selected gps satellite that (aircraft 901 carries out amendment during location
With data, doubtful distance correction value).
Threshold value determination computer 300 determine gps satellite select with computer 200 select gps satellite when as benchmark
Threshold value (hereinafter referred to as " threshold value that gps satellite is selected ").
Threshold value TH in 310 calculation of integrity of integrity thresholds calculating partI.Threshold value TH on the integrityIIt is for meeting
The threshold value of the safety (viability of location system) of aircraft navigation.
Persistence threshold calculations portion 320 calculates threshold value TH in persistenceC.Threshold value TH in the persistenceCIt is for meeting
The threshold value of location (persistence of location system).
Threshold value TH of the threshold value determining section 330 in persistenceCWith threshold value TH on integrityIIn the range of determine gps satellite
The threshold value selected.
VHF datacast apparatus 400 send the nothing that the reinforcement information generated with computer 200 is selected comprising gps satellite
Line signal.
Then, determine that to threshold value the process of 300 threshold value of computer is illustrated.As described above, threshold value determines calculating
Machine 300 determines that gps satellite selects computer 200 using the threshold value selected in gps satellite.Whenever gps satellite 801～805
Any one ephemeris data is updated, and gps satellite is selected computer 200 and has been updated the gps satellite of ephemeris data for this
Statistic of test R shown in calculating formula (1).
Here, (xo、yo、zo) be based on renewal before ephemeris data (hereinafter referred to as " old ephemeris ") and be calculated
, the position coordinateses of gps satellite in earth fixed coordinate system (WGS-84ECEF).In addition, (xn、yn、zn) it is based on after renewal
Ephemeris data (hereinafter referred to as " new ephemeris ") and be calculated, in earth fixed coordinate system (WGS-84ECEF)
The position coordinateses of gps satellite.
In addition, vector R represents the position (x from the gps satellite calculated based on old ephemeriso、yo、zo) to based on new
Ephemeris and the position (x of gps satellite that calculatesn、yn、zn) vector.Also, statistic of test R represent vectorial R size,
The straight line of the position of the position of the gps satellite for being calculated based on old ephemeris and the gps satellite calculated based on new ephemeris
Distance.Additionally, calculating the position of the gps satellite in earth fixed coordinate system (WGS-84ECEF) as based on ephemeris data
Calibration method is sat, described known method in GPS interface specification IS-GPS-200E can be used, omitted the description here.
Gps satellite is selected computer 200 and is judged to be not suitable for by statistic of test R bigger than predetermined threshold value GPS, and from
Exclude using in the gps satellite of 901 location of aircraft.On the other hand, gps satellite is selected computer 200 and by statistic of test R is
GPS below predetermined threshold value is judged to be adapted to, and selects to be the gps satellite used in 901 location of aircraft.When any one
When the ephemeris data of gps satellite is updated, threshold value determines that computer 300 is determined for determining whether that excluding this has been updated star
The threshold value of the gps satellite of ephemeris data.
Fig. 2 is to illustrate flow chart that threshold value determines the process step of 300 threshold value of computer.Additionally, be illustrated below
Each data value is for making the understandable example of explanation.Therefore, each data value can be taken beyond value shown below
Value.
First, threshold value determines that computer 300 sets maximum allowable detection probability of failure (although should be by certain gps satellite
Exclude from the location object of aircraft 901, the probability but not excluded) PMD(step S101).
For example, the manager of the GBAS grounds station 1 carry out integrity failure (as the GBAS grounds station 1, to aircraft
901 provide comprise more than predetermined permissible value error data failure) tree analysis (Fault Tree Analysis；
FTA), and determine maximum allowable detection probability of failure PMD.When integrity failure tree is analyzed, generate 1 institute of the GBAS grounds station
Integrity risk (for example, percent top for 0.00001) being set in fault tree, and determine and meet the integrity risk of requirement
Maximum allowable detection probability of failure PMD.Maximum allowable detection probability of failure PMDFor example it is confirmed as 5.71E-4 (percent
0.0571)。
Also, the manager of the GBAS grounds station 1 maximum allowable detection probability of failure P by determined byMDIt is input to threshold value
Determine computer 300, threshold value determines that computer 300 sets (store) the maximum allowable detection probability of failure P being transfused toMD。
Then, threshold value determines that computer 300 sets maximum allowable false alarm probability (although from the number of certain gps satellite
According to the probability that the normal, satellite is but excluded by the location object from aircraft 901) PFA(step S102).
For example, analyzing with the tree for carrying out integrity failure, the manager of the GBAS grounds station 1 carries out persistent failure
The tree analysis of (as the failure that data are provided without normal direction aircraft of the GBAS grounds station 1), and determine that maximum allowable false alarm is general
Rate PFA.Maximum allowable false alarm probability PFAFor example it is confirmed as 0.02E-6 (percent 0.000002).
Also, the manager of the GBAS grounds station 1 maximum allowable false alarm probability P by determined byFAIt is input to threshold value true
Determine computer 300, threshold value determines that computer 300 sets (store) the maximum allowable false alarm probability P being transfused toFA。
Then, threshold value determines that computer 300 is obtained in range areas (from aircraft 901 to the range determination of each gps satellite)
The limits of error (Maximum Tolerable Error；MERR)ΔρMERR(step S103).
Threshold value determines that computer 300 for example sets Δ ρMERR=0.6 meter (m).Additionally, known method can be used as obtaining
Limits of error Δ ρMERRMethod, omit the description here.
Then, threshold value determines that computer 300 sets fault-free (fault for each axle of satellite fixed coordinate system
Free) the marginal mode (step S104) of the standard deviation of the ephemeris error under state.For example, the pipe of the GBAS grounds station 1
The value that the ephemeris data being broadcasted in the past is determined by off-line analysis is input to threshold value and determines computer 300, threshold by reason person
Value determines that computer 300 sets (store) value being transfused to.
Ephemeris error mentioned here is the error of the positional information shown in the ephemeris data sent from gps satellite.
In addition, it is state within predetermined permissible value that described unfaulty conditions is ephemeris error.
In addition, using following coordinate system as satellite fixed coordinate system.First, X-axis is set to the edge of satellite orbit
Footpath (Along Track) direction (direct of travel), by σaThe boundary mould of the standard deviation of ephemeris error along footpath direction is shown
Type.In addition, by Y-axis be set to satellite orbit friendship footpath (Cross Track) direction (it is orthogonal with direct of travel, and Earth surface plane it is flat
Capable direction), use σcThe marginal mode of the standard deviation of the ephemeris error for handing over footpath direction is shown.In addition, Z axis are set to satellite
Radial direction (Radial) direction (vertical (vertical with Earth surface plane) direction) of track, uses σkThe ephemeris error of radial direction is shown
Standard deviation marginal mode.
Additionally, marginal mode mentioned here is referred to：In the case where the probability distribution of error is different from normal distribution, tool
There is the normal distribution of the standard deviation of the minimum that can cover the probability of error distribution." covering " mentioned here is to represent：
During the cumulative distribution of the cumulative distribution and normal distribution of relative error probability distribution, the cumulative distribution of probability of error distribution compares normal state
The cumulative distribution of distribution is little.
As the method for the marginal mode of the standard deviation of the ephemeris error obtained under unfaulty conditions, can be using public affairs
The method known, is omitted the description here.
For example, threshold value determines that computer 300 is set to the boundary of the radially standard deviation of the ephemeris error in (Radial) direction
Limit model σk=3 meters, along footpath (Along Track) direction ephemeris error standard deviation marginal mode σa=14 meters, friendship
The marginal mode σ of the standard deviation of the ephemeris error in footpath (Cross Track) directionc=6 meters.
Then, threshold value determines that computer 300 (persistence threshold calculations portion 320) is missed based on the ephemeris under unfaulty conditions
Poor distribution and the limits of error alarm probability P for setting in step s 102FADetermine threshold value TH in persistenceC(step
S105)。
First, the probability of scope (by the value after the size criteria of the ephemeris error) r of the three-dimensional error being standardized
Density P (r) is as shown in formula (2).
Here, π represents pi, and exp represents exponential function (Exponential Function).
Also, it is general that persistence threshold calculations portion 320 obtains the accumulation that P (r) is integrated gained from r=0 to the forward direction of r
Rate is 1-PFAWhen r value (below by rCIllustrate).Value rCRepresent and meet maximum allowable false alarm probability PFAAnd should allow
Error scope (size after being standardized) minima.
Here, the marginal mode R of the distribution of statistic of testboundUsing the marginal mode of step S105 Plays deviation
σk、σa、σcIn illustrate maximum (14 meters) the ephemeris error along footpath (Along Track) direction standard deviation boundary
Model σa, and can be expressed as Therefore, persistence threshold calculations portion 320 is to formulaSubstitute into σaValue and rCValue, thus obtains threshold value TH in persistenceC。
Thus, the σ of the marginal mode using standard deviationk、σa、σcIn marginal mode (the superincumbent example of maximum is shown
It is σ in sona) obtain threshold value TH in persistenceC, thus, it is possible to simplified solution formulas and cut down the meter in persistence threshold calculations portion 320
Calculation amount, is met the maximum allowable false alarm probability P being setFAPersistence on threshold value THC。
That is, persistence threshold calculations portion 320 is due to replacing the boundary of standard deviation with the marginal mode for illustrating bigger error
Model σkAnd σcTo obtain threshold value TH in persistenceC, therefore, it is possible to be met the maximum allowable false alarm probability being set
PFAThreshold value THC, also, by using marginal mode σaDisplacement marginal mode σkAnd σc, calculating formula can be made to simplify and cut down meter
Calculation amount.
Then, threshold value determines that computer 300 calculates maximum allowable ephemeris error (Maximum Acceptable
Ephemeris Error；MAEE)rMAEE(step S106).
Here, maximum allowable ephemeris error rMAEEIllustrate the maximum for being allowed for error as according to new ephemeris meter
Error of the position of the gps satellite of calculation away from the actual location of the gps satellite.
First, to maximum allowable ephemeris error rMAEECalculating formula illustrate.
Here, Fig. 3 is that the position for illustrating the GBAS grounds station 1 (the benchmark station 100), gps satellite and aircraft 901 is closed
The explanatory diagram of each variable of system.As shown in the drawing, the distance of the benchmark station 100 and the actual location of gps satellite is represented with D.
In addition, by the distance of the benchmark station 100 and the position of the gps satellite using new Calculation for Ephemerides with ^D (^ represents cap mark, similarly hereinafter)
Represent.
In addition, satellite orbital error vector is (from actual location TP of gps satellite to the GPS calculated using new ephemeris
The vector of the position NEP of satellite) use vector rsIllustrate, by its transposed vector vector rs TIllustrate.In addition, will appear on the stage from GBAS
Stand 1 to determine object gps satellite direction unit vector with vector 1sIllustrate, by its transposed vector vector 1s TIllustrate.Separately
Outward, by it is being estimated according to ephemeris data, from the GBAS grounds station 1 to the unit vector in the gps satellite direction of determine object use
Vectorial ^1sIllustrate, by its transposed vector vector ^1s TIllustrate.In addition, by vector 1sWith vectorial ^1sError vector (from vectorial ^
1s TDeduct vector 1sDifference afterwards) use vectorial Δ 1sRepresent, by its transposed vector Δ 1s TIllustrate.
In addition, basic lineal vector (from the benchmark station 100 to the vector of aircraft 901) is used vector xairIllustrate.
In addition, by satellite orbital error vector rsWith basic lineal vector xairThe angle of composition is illustrated with θ (0 °≤θ≤180 °), is incited somebody to action
Vector 1sWith basic lineal vector xairThe angle of composition α (180 ° of 0 °≤α ＜, from the station of GBAS grounds, as aircraft 901 is located at
(overhead side) more top than horizon, therefore do not include α=180 °) illustrate, by satellite orbital error vector rsWith vector 1sConstitute
Angle illustrated with β (0 °≤β≤180 °).
In addition, the unit matrix I for arranging 3 rows 33×3Illustrate.
Then, by difference coverage error Δ ρ caused by ephemeris errorairAs shown in formula (3).
By difference coverage error Δ ρ caused by the ephemeris errorairIt is the aircraft 901 calculated using new ephemeris
Position and aircraft 901 actual location error.Additionally, below by difference coverage error Δ ρairPermission maximum Δ
ρMERR(Maximum Error In Range) is illustrated.Additionally, the deriving method of formula (3) is known, omit the description here.
Relation according to formula (3), formula (4) is set up.
In addition, α and β are independent, θ is the function of α and β, can be expressed as θ=f (α, β).Due to according to its restriction
The absolute value of (cos (θ)-cos (β) cos (α)) is less than 1, therefore, it is possible to obtain formula (5).
When by the difference coverage error Δ ρ in formula (5)airBeing set to which allows maximum Δ ρMERRWhen (as Δ ρairIt is set
To become the permission maximum under the worst case (Worst Case) of maximum), formula (6) can be obtained.
Here, maximum allowable ephemeris error rMERRAs satellite orbital error vector rsSize and obtain.Accordingly, it is capable to
Maximum allowable ephemeris error r is obtained by formula (7) enoughMERR。
Therefore, threshold value determines that computer 300 uses formula (7) to calculate maximum allowable ephemeris error rMAEE。
Here, as an example, as shown in formula (8), the permission maximum Δ ρ of difference coverage errorMERRIt is 0.6 meter,
In addition, as shown in formula (9), minima D apart from D of the GBAS grounds station and gps satellite (actual location)minIt is 20,000000
Rice, in addition, as shown in formula (10), to from the benchmark station 100 to the vector x of aircraft 901airSize (the benchmark station 100 and fly
The distance of machine 901) maximum be 23 nautical miles of (Nautical Mile；The situation of NM)=42.6 kms is illustrated.
ΔρMERR=0.6 [m] ... (8)
Dmin=20,000 [km] ... (9)
||xair_max| |=23 [NM]=42.6 [km] ... (10)
Δ ρ shown in formula (8)MERRValue 0.6 be the allowable error that aircraft 901 is capable of safe navigation setting example.
In addition, the D shown in formula (9)min20,000 km of value be gps satellite be located at the GBAS grounds station surface when
Distance example.In formula (4), D is expressed as the denominator on the right, and the value of D is less, difference coverage error Δ ρairIt is bigger.
That is, DminIt is relevant with the value of D, represent difference coverage error Δ ρairFor maximum worst case.
In addition, shown in formula (10), basic lineal vector xairMaximum xair_maxSize 23 show in the sea and be confirmed as
Aircraft 901 becomes the scope of GBAS user, and (aircraft 901 receives GBAS update informations carrying out the model of location from the GBAS grounds station
Enclose) ultimate range example.In formula (4), basic lineal vector xairOccur in the denominator on the right, basic lineal vector xairSize
It is bigger, difference coverage error Δ ρairIt is bigger.That is, xair_maxWith xairIt is relevant, represent difference coverage error Δ ρairFor maximum most
Difference situation.
In this case, threshold value determines computer 300 as shown in formula (11), calculates maximum allowable ephemeris error rMAEEFor
281.7 rice.
As described above, utilize absolute value≤1 of (cos (θ)-cos (β) cos (α)) and formula (5) is obtained according to formula (4), by
This simplified solution formulas can obtain the permission maximum Δ ρ of the location error for meeting aircraft 901MERRMaximum allowable ephemeris
Error rMAEE。
That is, threshold value determines computer 300 due to being maximum situation, i.e. (cos (θ)-cos (β) for ephemeris error
Cos (α)) the situation of absolute value=1 obtain maximum allowable ephemeris error rMAEE, aircraft 901 is met therefore, it is possible to obtain
The permission maximum Δ ρ of location errorMERRMaximum allowable ephemeris error rMAEE, also, due to being set to (cos (θ)-cos (β)
Cos (α)) absolute value=1, amount of calculation is cut down therefore, it is possible to simplified solution formulas.
Then, threshold value determines computer 300 (integrity thresholds calculating part 310) based on maximum allowable ephemeris error
rMAEE, ephemeris error under unfaulty conditions distribution and the maximum allowable detection failure that sets in step S101 it is general
Rate PMDDetermine threshold value TH on integrityI(step S107).
Here, Fig. 4 is to be shown with the position of gps satellite obtained by new ephemeris, defended using GPS obtained by old ephemeris
The explanatory diagram of each variable of the relation between the position of star and the actual location of gps satellite.As shown in the drawing, comprising being based on
The statistic of test r of the abnormal biasing of ephemerisfaultDrawn by formula (12).
rfault=rs_o-(rMARR+rs_n)
=(rs_o-rs_n)-rMARR
=rfault-free-rMARR …(12)
Here, vectorial rs_oIt is the position from actual location TP of gps satellite to the gps satellite drawn using old ephemeris
Put the vector (representing the vector of the error of old ephemeris) of FOEP.Additionally, using the position of the gps satellite obtained by old ephemeris
FOEP is set to fault-free (error is below predetermined permissible value).In addition, vector rs_nIt is in the case of new ephemeris is trouble-free
From vector (table of actual location TP of gps satellite to the position FNEP using the gps satellite obtained by trouble-free new ephemeris
Show the vector of the error of old ephemeris).
In addition, here by maximum allowable ephemeris error rMAEEIt is set to from using GPS obtained by trouble-free new ephemeris
The position FNEP of satellite is to the position using gps satellite obtained by abnormal (permissible value of error ratio threshold value is big) new ephemeris
The size of the vector of ANEP.
That is, the usual GBAS grounds station 1 (threshold value determines that computer 300 or gps satellite select computer 200) cannot be examined
Actual location TP of gps satellite is surveyed, but trouble-free new ephemeris is estimated using past trouble-free ephemeris data, and
The position of gps satellite can be obtained using the new ephemeris being estimated.
Therefore, the GBAS grounds office 1 using using the position of gps satellite obtained by the new ephemeris for estimating as benchmark,
The air line distance according to obtained by the new ephemeris that gps satellite is received between the position of gps satellite and the benchmark will be used to be set to
Maximum allowable ephemeris error rMAEE。
In formula (12), in vectorial rfault_freeWith vectorial rMAEEIn the case of being equidirectional, vectorial rfaultSize
For minimum.That is, it is minimum as the difference of the position of the gps satellite based on new and old ephemeris of statistic of test, is on integrity
Worst condition (be judged to that new ephemeris is inappropriate according to minimum statistic of test, needs will send the GPS of the new ephemeris
The situation that satellite is excluded).
The vectorial rfault_freeWith vectorial rMAEEIt is in the case of equidirectional, vector rfaultSize (use rfaultTable
Show) drawn by formula (13).
rfault=| | rfault| |=| | | rfault-free||-||rMARR| | |=| rfault-free-rMARR| …(13)
Here, as illustrated in step S105, can be expressed asWhen shouldIt is applied to the r of formula (13)fault_freeWhen, formula (14) can be obtained.
On the other hand, scope (to the value after the size criteria of the ephemeris error) r's of the three-dimensional error being standardized
Probability density P (r) is as shown in previously described formula (2).Therefore, integrity thresholds calculating part 310 obtain by the P (r) from r=0 to r just
It is 1-P to cumulative probability obtained by being integratedMDWhen r value (use r belowIIllustrate).
Also, use value rI, threshold value TH on integrityIAs shown in formula (15).Therefore, integrity thresholds calculating part 310
TH is obtained based on the formula (15)I。
For example, it is identical with step S104, the marginal mode σ of maximum is being showna=14 meters, and the maximum of r is set
For in the case of 7 (maximum of the r be the cumulative probability that the forward direction by P (r) from r=0 to r is integrated gained be 1 when
(becoming sufficiently small with 1 difference) r), On the other hand, exist
Maximum allowable ephemeris error r obtained in step S106MAEEValue be 281.7 (rice),Cause
This,Formula (15) is
Also, in maximum allowable detection probability of failure PMDIn the case of=5.71E-4,1-PMD=0.999429.Therefore,
As described above, integrity thresholds calculating part 310 is calculated by P (r) from r=0 to cumulative probability obtained by the forward direction of r is integrated being
1-PMDWhen r value, obtain rI=4.178.
In addition, maximum allowable ephemeris error rMAEE=281.7 (rice), are the marginal mode σ for illustrating maximuma=14
(rice), integrity thresholds calculating part 310 are calculated
Obtain threshold value TH on integrityIValue 199.0 (rice).
As described above, by assuming vector rfault_freeWith vectorial rMAEEIt is the situation of equidirectional and obtains from formula (12)
Formula (13), threshold value TH that can be on simplified solution formulas the integrity of the requirement for being met integrity riskI。
That is, integrity thresholds calculating part 310 is the worst case on integrity, due to for vector rfault_freeAnd vector
rMAEEIt is that the situation of equidirectional obtains threshold value TH on integrityI, therefore, it is possible to be met the complete of the requirement of integrity risk
Threshold value TH in whole propertyI, also, by by vectorial rfault_freeWith vectorial rMAEEEquidirectional is set to, being capable of simplified solution formulas
(formula (12) of the formula as vector is replaced into into the formula (13) of the formula as scalar particularly) and cut down amount of calculation.
Then, threshold value determines that can computer 300 (threshold value determining section 330) judge set and meets calculated persistence
On threshold value THCAnd threshold value TH on integrityIThreshold value.
Specifically, threshold value determining section 330 is for THC≤THIIn the case of, it is judged to set (step S108).
In the case of the above-described example, THC=123.2 meters, THI=199.0 meters, meet THC≤THI.Therefore, threshold value is true
Determine portion 330 and be judged to energy given threshold.
In the case where energy given threshold is judged to, threshold value TH of the threshold value determining section 330 in persistenceCOn integrity
Threshold value THIIn the range of determine the threshold value selected of gps satellite, (threshold value determines computer 300) selects calculating to gps satellite
Machine 200 is transmitted.In the case of the above-described example, the threshold value that gps satellite is selected is defined as TH by threshold value determining section 330C
=123.2 meters and THIValue (such as 161.1 meters of meansigma methodss) between=199.0 meters, and be sent to gps satellite and select computer
200.Gps satellite is selected computer 200 using the threshold value to carry out the selection of gps satellite, thus, it is possible to meet maximum allowable inspection
Survey probability of failure and maximum allowable alarm probability.
On the other hand, for THC＞ THIIn the case of, threshold value determining section 330 is judged to be unable to given threshold, and threshold value determines
Computer 300 carries out fault processing.For example, threshold value determines that computer 300 carries out mistake for the manager of the GBAS grounds station 1
Represent.As the correspondence of the manager of the GBAS grounds station in this case, for example, consider to confirm the GBAS grounds station 1 (especially
Be the benchmark station 100) in device have fault-free etc..
Fig. 5 be the distribution of scope r for illustrating the three-dimensional error being standardized and can be between given threshold scope relation
Explanatory diagram.Here, rCIllustrated by formula (16), rIIllustrated by formula (17).
The position of the r according to the figure, formula (18) has represented the distribution L12 that the fault-free of r is distributed after L11 reversions
Worst case in whole property.
Threshold value determines the P that computer 300 is set according to the distribution and by step S101MDObtain rI.Thereby, it is possible to obtain
Use PMDFollowing detection probability of failure can detect rMAEEThe threshold value of error above.
As described above, threshold value determining section is due to based on the maximum allowable detection probability of failure and maximum allowable false alarm being set
Report determine the probability is used to select the threshold value of gps satellite, therefore, it is possible to obtain can be while meet the viability and location of location system
The threshold value of the persistence of system.
In addition, persistence threshold calculations portion for gps satellite satellite orbit along footpath (Along Track) direction and friendship
The boundary mould of the standard deviation of each setting ephemeris error in footpath (Cross Track) direction and radial direction (Radial) direction
Type, and calculated based on the marginal mode using the distribution of statistic of test obtained by marginal mode maximum in the marginal mode
Threshold value in persistence, therefore, it is possible to simplified solution formulas, and obtains the permission maximum Δ of the location error for meeting aircraft 901
ρMERRMaximum allowable ephemeris error rMAEE。
In addition, integrity thresholds calculating part due to being directed to vector r when ephemeris data is updatedfault_freeAnd vector
rMAEEIt is the threshold value in the situation calculation of integrity of equidirectional, integrity risk is met therefore, it is possible to simplified solution formulas
Requirement integrity on threshold value THI, wherein the vectorial rfault_freeIt is obtained by the ephemeris data from after based on renewal
The vector of the position of gps satellite, the vector obtained by the ephemeris data of the position of gps satellite to before based on renewal
rMAEEIt is from based on the gps satellite according to obtained by the ephemeris data estimated value after the renewal that past ephemeris data is estimated
Ephemeris data of the position to before based on renewal obtained by gps satellite position vector.
Additionally, will calculate for realizing that threshold value determines that the program of the function of the whole of computer 300 or is recorded
In the recording medium that machine can read, it is possible to make computer system read in program of the record in the recording medium, and by holding
The process for going to carry out each several part.Additionally, " computer system " mentioned here is assumed to set comprising the hardware such as OS and ancillary equipment
Standby system.
In addition, " computer system " is if make use of the situation of WWW system, then it is set to also provide environment comprising homepage
(or display environment).
In addition, described " recording medium of embodied on computer readable " refers to that floppy disk, photomagneto disk, ROM, CD-ROM etc. may move
The storage device such as medium and built-in hard disk in computer systems.Also, described " record Jie of embodied on computer readable
Matter " be set to also comprising via as the communication line during communication line router such as the networks such as the Internet or telephone wire in short-term
Between during dynamically keep the equipment of program and such as becoming in the computer system of server and client side in this case
The volatile memory in portion keeps the equipment of certain hour program like that.In addition, said procedure could be for realizing the work(
A part for energy, can also be described function and reality is combined to already recorded in the program in computer system
It is existing.
More than, refer to the attached drawing is described in detail to embodiments of the present invention, but specific structure is not limited
In the embodiment, design change of the scope also comprising the purport without departing from the present invention etc..
Claims (5)
1. a kind of threshold determining apparatus, the threshold determining apparatus are determined for selecting to send from multiple gps satellites using existing
The threshold value of the gps satellite of the ephemeris data on location, it is characterised in that
With threshold value determining section, the threshold value determining section is based on the maximum allowable detection probability of failure and maximum allowable mistake being set
Alarm probability determining for selecting the threshold value of the gps satellite,
The maximum allowable detection probability of failure is that while certain gps satellite to be excluded from the location object of aircraft, but
There is no the probability for excluding,
The maximum allowable false alarm probability is that while that the data from certain gps satellite are normal, the gps satellite is but by from flying
The probability excluded in the location object of machine.
2. threshold determining apparatus as claimed in claim 1, it is characterised in that
Including：
Integrity thresholds calculating part, the integrity thresholds calculating part are calculated and meet the complete of the maximum allowable detection probability of failure
Threshold value in whole property；And
Persistence threshold calculations portion, the persistence threshold calculations portion calculate and meet continuing for the maximum allowable false alarm probability
Threshold value in property,
Wherein, the threshold value determining section is according to more than or equal to the threshold value in the persistence and less than or equal on the integrity
The mode of threshold value is determined for selecting the threshold value of the gps satellite.
3. threshold determining apparatus as claimed in claim 2, it is characterised in that
The persistence threshold calculations portion is for the direct of travel of the satellite orbit as the gps satellite along footpath direction, work
Be it is vertical with the direct of travel and be horizontally oriented hand over footpath direction and as vertical radial direction each come
The marginal mode of the standard deviation of setting ephemeris error, and based on the marginal mode using the maximum in the marginal mode
Statistic of test distribution marginal mode calculating the threshold value in the persistence.
4. threshold determining apparatus as claimed in claim 2 or claim 3, it is characterised in that
The integrity thresholds calculating part calculates the integrity when the ephemeris data is updated for following situation
On threshold value, the situation refers to：From the position of the gps satellite obtained by the ephemeris data after based on renewal to based on more
The vector of the position of the gps satellite obtained by ephemeris data before new and from based on according to past ephemeris data
Ephemeris of the position of the gps satellite to before based on the renewal obtained by ephemeris data estimated value after the renewal for estimating
Obtained by table data, the vector of the position of the gps satellite is equidirectional.
5. a kind of Threshold, the Threshold determine and are used for selecting to send from multiple gps satellites
The threshold value of the gps satellite of the ephemeris data on location, it is characterised in that
Step is determined including threshold value, the threshold value determines that step is permitted based on the maximum allowable detection probability of failure and maximum being set
Perhaps false alarm determine the probability is used for the threshold value for selecting the gps satellite,
The maximum allowable detection probability of failure is that while certain gps satellite to be excluded from the location object of aircraft, but
There is no the probability for excluding,
The maximum allowable false alarm probability is that while that the data from certain gps satellite are normal, the gps satellite is but by from flying
The probability excluded in the location object of machine.
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| FR3013851B1 (en) * | 2013-11-22 | 2016-01-08 | Thales Sa | SYSTEM AND METHOD FOR DETERMINING THE POSITION ERROR OF A SATELLITE LOCATION RECEIVER |
| TW201543058A (en) * | 2014-02-27 | 2015-11-16 | Nec Corp | Satellite positioning-use radio wave interference detection mechanism and method, and augmentary information transmission system provided with satellite positioning-use radio wave interference detection mechanism |
| US9678212B2 (en) * | 2014-02-28 | 2017-06-13 | Honeywell International Inc. | Satellite measurement screening to protect the integrity of existing monitors in the presence of amplitude scintillation |
| US9964645B2 (en) * | 2014-02-28 | 2018-05-08 | Honeywell International Inc. | Satellite measurement screening to protect the integrity of existing monitors in the presence of phase scintillation |
| CN104950316B (en) * | 2015-04-20 | 2021-10-26 | 中国电子科技集团公司第二十研究所 | Method, device and system for detecting consistency of broadcast ephemeris data |
| CN105866809A (en) * | 2016-05-31 | 2016-08-17 | 天津七二通信广播有限公司 | Ground-based augmentation system ground station equipment with assemblies having hot standby switching function and hot standby switching method |
| CN105891846A (en) * | 2016-05-31 | 2016-08-24 | 天津七二通信广播有限公司 | High-reliability base reinforcing system ground station equipment and online switching method |
| US11168984B2 (en) * | 2019-02-08 | 2021-11-09 | The Boeing Company | Celestial navigation system and method |
| CN110806733B (en) * | 2019-10-30 | 2021-09-21 | 中国神华能源股份有限公司国华电力分公司 | Thermal power plant equipment monitoring method and device and electronic equipment |
| CN110780261B (en) * | 2019-10-31 | 2021-12-24 | 南京国电南自电网自动化有限公司 | Method and system for checking electric quantity acquisition data |
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