CN102096075B - Galileo system integrity concept-based multimode user integrity assessing method - Google Patents

Abstract

The invention belongs to the field of the integrity study of a satellite navigation system in the technical field of earth observation and navigation, and provides a Galileo system integrity concept-based multimode user integrity assessing method. In the method, the conventional Galileo user integrity concept is used in two systems directly, for a non-Galileo system (such as European geostationary navigation overlay service (EGNOS)), input parameters are needed to be pretreated appropriately, so that the input parameters are converted into information available in a Galileo user integrity algorithm, and the change in values of an integrity risk (IR) and/or a protection level (xPL) is monitored during integrity analysis. In the method, the assessment of multisystem user integrity is realized by using a more advanced Galileo system integrity concept; and by comparing and analyzing integrity calculation results of a single system and a multisystem, the availability of positioning resultsof users is improved substantially under the condition of the multisystem, and the user integrity is improved to a large extent.

Description

Multimode user's integrity appraisal procedure based on Galileo system health concept

Technical field

The invention belongs to earth observation and field of navigation technology satellite navigation system integrity research field, particularly relate to a kind of multimode user's integrity appraisal procedure based on Galileo system health concept.

Background technology

GPS (Global Position System) mainly comprises GPS of USA at present, Muscovite GLONASS, the BD system of the European Galileo that is building and China in addition.And its corresponding strengthen and the integrity technology also among progressively development and improving.Up to now, at single constellation satellite navigation system multiple integrity technology has been proposed, from the realization level, mainly be divided three classes: the one, receiver-autonomous integrity RAIM (Receiver Autonomous Integrity Monitoring) is the integrity of terminal level.The 2nd, satellite-based augmentation system SBAS (Satellite Based Augmentation System) and ground strengthen the GBAS of system (Ground BasedAugmentation System), belong to the outer zonal integrity technology of satellite navigation system.The 3rd, the global integrity technology at the Galileo satellite navigation system is embedded in the Galileo system.

RAIM technology transition period before Wide Area Augmentation System occurs puts forward, and can be divided three classes: compare and locator field relative method, least-square residuals method and odd even means of space vector representation in the pseudorange territory.Its principal feature is only to utilize current observed quantity, supposes the stationarity of random noise, is referred to as snapshot (Snapshot).The RAIM technology depends on redundant observed quantity, calculated level protection limit value and vertical protection limit value.But effective estimation space signal errors.

The weak point that the RAIM technology exists mainly contains: 1) mean allocation integrity risk (Integrity Risk) between satellite.But in fact every batch is different with probability of malfunction every satellite, thereby can not mean allocation.2) its hypothesis according to the formula foundation of evolution distribution (Chi-Square) calculated level protected level limit value HPL (Horizontal Protection Limit) is very conservative; be about to some probability that can correctly detect and bring in the false dismissal probability, thereby greatly reduce availability.3) the integrity risk of between level protection limit value HPL and vertical protection limit value VPL (Vertical Protection Level), distributing locator field according to 1% and 99% fixed proportion.In fact, the probability of happening of dangerous misleading information HMI (Hazardous Misleading Information) is not but abideed by fixed proportion.

SBAS adopts and to carry out behind the differential correcting method of estimation space signal residual error again, calculate integrity parameter UDRE (User Differential Range Error) and grid points ionosphere vertical error GIVE (Grid IonosphericVertical Error) on this basis, and real-time verification UDRE and GIVE reach the integrity requirement.

The user corrects broadcasting satellite coordinate and clock correction according to difference information earlier, and single-frequency user utilizes ionosphere delay information to correct the ionosphere delay influence.The recycling integrity information calculates XPL (HPL﹠amp; VPL).At last with XPL and protection limit value XAL (HAL﹠amp; VAL) relatively, judge whether to meet the demands.

The weak point of SBAS integrity mainly contains: the signal in space error after 1) the protected level hypothesis corrects is to satisfy no polarization attitude to distribute.Although SBAS in real time/quasi real time broadcast the differential correcting data.But the precision that the orbit determination of SBAS and clock correct is not high, so often can not satisfy under the situation of assumed condition the do not give security means of user's integrity risk of SBAS in real data.2) SBAS exists and the similar conservative design problem of RAIM, namely distributes integrity probability demands (WAAS is according to 2% and 98%) according to fixed proportion between horizontal protected level HPL and vertical protected level VPL.

In the Galileo system, be the essential step of system health technology to the monitoring of spacing wave and the alarm of transfiniting, system's utilization is distributed in the monitoring station network in the whole world situation of spacing wave SIS (Signal in Space) is estimated in real time, and when guaranteeing that with certain misinformation probability signal in space error SISE (Signal in Space Error) surpasses limit value, in time to User Alarms.Integrity processing subsystem IPF in the Galileo system (Integrity processing Facility) and the synchronous processing subsystem OSPF of track (Orbitography and Synchronisation Processing Facility) can reach the data sharing of height, utilize high-precision Satellite Orbit Determination and atomic clock data, can greatly improve the precision that signal in space error is estimated.Compare with the SBAS system, the integrity risk probability in the direct compute location of Galileo system user territory no longer is assigned to horizontal direction and vertical direction with the integrity risk probability according to fixed proportion.The fixed proportion allocation scheme of this and protected level has had basic difference.User's integrity of Galileo has not only been considered the integrity risk that no polarization attitude distributes, and has considered to have the integrity risk when inclined to one side.

Many constellations of GPS/GLONASS/Galileo/BD satellite navigation system is for single constellation systems, mainly contain two advantages: the one, number of satellite is multiplied, the availability of navigation signal under the environment such as raising housing-group, the 2nd, the observed quantity redundance increases, and the easier integrity of carrying out detects.

To sum up, on the one hand because there is certain conservative property in the integrity technology of systems such as existing SBAS and RAIM, can not be true, objectively reflection system positioning result is to user's availability, on the other hand because the limited availability that limits positioning result to a great extent of single constellation systems bearing accuracy, and following building up along with BD and Galileo system, the optional constellation of user increases, multisystem compatible receiver will become following development trend, thereby for the user provides high-precision positioning service, and assess a new demand that also will become high precision high reliability satellite application field at the integrity of multisystem user positioning solution.

Summary of the invention

In view of above defective, fundamental purpose of the present invention is to provide a kind of multimode user's integrity appraisal procedure based on Galileo system health concept, utilization of the present invention is science comparatively so far, advanced Galileo integrity concept, realize multisystem user's integrity evaluation problem, solve SBAS in the past on the one hand, the conservative property problem of the integrity concept of systems such as RAIM, system-level integrity information with a plurality of systems passes through conversion and fusion on the other hand, become information available in Galileo user's integrity concept, the system-level integrity information of having realized a plurality of systems calculates in the fusion of user side, thereby solved the integrity evaluation problem of multisystem user's positioning solution, and provide service for the user jointly by a plurality of systems, thereby improved the reliability of system, namely improved the integrity of user's positioning result.

This kind provided by the invention is based on multimode user's integrity appraisal procedure of Galileo system health concept, it is user's integrity concept of directly using present Galileo two systems, need be to some input parameters for non-Galileo system (as EGNOS), than integrity data UDRE and UIRE, do suitable pre-service, be converted into Galileo user's integrity algorithm information available, when carrying out the integrity analysis, the numerical value change of monitoring integrity risk (IR) gets final product.IR is defined as the user should receive warning message, but does not receive the probability of warning message, and this situation is called as high-risk misleading information (HMI).IR is that the absolute value of the biased difference of estimation point is greater than the probability of warning limit value (AL) given in advance.If result of calculation has exceeded the threshold value T (depending on certain specific application) that presets, think that then the probability of HMI was too high when navigation information was received.

This kind is as follows based on the concrete steps of multimode user's integrity appraisal procedure of Galileo system health concept:

1) obtain navigation information, at first determine the satellite position vector of GPS constellation according to the broadcast ephemeris data of being downloaded by the IGS website, the navigation information of another one constellation obtains according to Galileo constellation systems parameters simulation;

2) obtain navigational solution, under the normal condition, this value should be determined by broadcast ephemeris, observation data, weather data that receiver receives, adopts the wuhn station of known exact position coordinate as subscriber station among the present invention;

3) calculating observation matrix, according to the position vector of two constellation satellites that can observe and the observing matrix G of receiver location vector calculation subscriber station, formula is as follows:

G _i=[cosEl _iSinAz _i-cosEl _iCosAz _i-sinEl _i1]=i of G matrix is capable;

El in the formula _iBe the elevation angle of i satellite, Az _iIt is the position angle of i satellite;

4) obtain integrity information, almanac data, observation data, weather data and subscriber station information calculations Galileo system health parameter S ISMA, SISA according to the IGS download, obtain GPS constellation integrity data, i.e. EGNOS integrity data UDRE, UIRE according to existing rule emulation again.Integrity information and UERE table according to two systems calculate every satellite " total pseudorange deviations _{U, RX}[i] ", wherein to user's broadcast, the user can receive by receiver by satellite for parameter S ISMA, SISA and UDRE, this Several Parameters of UIRE;

" total pseudorange deviation " is to calculate the prediction standard deviation value of total pseudorange deviation that the signal of each visible satellite causes.The pseudorange deviation computing formula total for the Galileo system is as follows:

${\mathrm{\σ}}_{u,\mathrm{RX}}\left[i\right]=\sqrt{{\mathrm{\σ}}_{\mathrm{SISA}}^2\left[i\right]+{\mathrm{\σ}}_{u,L}^2\left[i\right]}---\left(1\right)$

In the formula,

σ _SISA[i] is the broadcast parameter SISA of i satellite using of user class, and the SISA that it equals the broadcasting of navigation spots position multiply by a definite factor, and SISA definition here is the lowest standard deviation of no higher this distribution, so can think

σ _SISA[i]＝SISA[i]]。

σ _UL[i] is added on i this ground error (troposphere, noise, multipath etc.) prediction standard deviation on the satellite-signal.The standard deviation value of this ground error can read from UERE (User Equivalent Range Error) table, and typical UERE value list is as follows:

Table 1.UERE table

ID	01	02	03	04	05	06	07	08
									The elevation angle [rad]	0.1745	0.2618	0.3491	0.5236	0.6981	0.8727	1.0472	1.5708
σ u，L[m]	1.03	0.78	0.67	0.6	0.58	0.57	0.56	0.55

For gps system, certain the total pseudorange deviation of satellite can adopt (1) formula to calculate equally, and just some parameter of using in the computation process need be through the equivalence conversion of following process.

The EGNOS broadcast is corrected at the error of gps satellite clock, ephemeris, ionosphere delay, and it goes back the pseudorange residual error parameter after clock correction-ephemeris correction (UDRE), ionosphere correction (GIVE) have been used in broadcast simultaneously;

The integrity monitoring Useful Information is made up of observation quality and geological information.Observation quality information provides with the form of standard deviation, and corrects relevant with two classes:

UDRE _i: be the clock correction of the remnants that still have of the pseudorange after i satellite corrects and the variance of ephemeris error.Can directly from broadcast message, obtain;

UIRE _i: the variance that is the residual ionospheric error that still has of the pseudorange after i satellite corrects.It corrects variances sigma from the GIVE of broadcasting and the vertical ionosphere of calculating _UIVEObtain in the ionospheric model of forming;

Geological information comprises the almanac data of distance-measuring satellite, is the satellite position of function from estimating here with time.It comprises:

Satellite almanac data

Correction data to satellite position;

The EGNOS/Galileo conversion need be carried out equivalence with SISA and the SISMA integrity parameter of EGNOS system health parameter UDRE and UIRE and Galileo system, and conversion formula is as follows:

σ _SISA，GPS[i]＝f _SISA，GPSσ _UDRE[i] (1)

σ _SISMA，GPS[i]＝f _SISMA，GPSσ _UDRE[i] (2)

Here, σ _UDRE[i] is the standard deviation of the user's pseudorange error that is caused by orbit error and clock correction of i satellite, and computing formula is as follows:

${\mathrm{\σ}}_{i,\mathrm{UDRE}}^2={({\mathrm{UDRE}}_i/3.29)}^2$

In the formula: f _{SISA, GPS}And f _{SISMA, GPS}Be the experience factor that obtains through after the algorithm calibration, can obtain this two parameters by data result statistics, comparison and analysis;

If consider the integrity distribution method that Galileo is different with EGNOS, Galileo uses four kinds of failure mechanisms, and EGNOS supposes that based on non-fault at the gps satellite situation, it is possible reducing the input variable number, single satellite failure probability can be put 0 (p _Fail=0), avoided use SISMA equivalent variable accordingly.On this meaning, gps satellite can reduce to single non-fault mode to the contribution that IR calculates.Certainly, also might suppose f _{SISMA, GPS}=0 and first rank are similar to f _{SISA, GPS}=1.

Calculate the equivalence margin deviation formula of this ground error:

${\mathrm{\σ}}_{u,L,\mathrm{GPS}}^2\left[i\right]={\mathrm{\σ}}_{\mathrm{UIRE}}^2\left[i\right]+\left({\mathrm{\σ}}_{\mathrm{air}}^2\right[i]+{\mathrm{\σ}}_{\mathrm{tropo}}^2[i\left]\right)---\left(3\right)$

σ _{U, L, GPS}Be local receiver noise, multipath noise (σ _Air), troposphere (σ _Tropo), ionosphere (σ _UIRE) standard deviation of the composition error that causes.

${\mathrm{\σ}}_{\mathrm{UIRE}}^2\left[i\right]=\frac{1}{1-\left(\cos \mathrm{EL}\right[i]/(1+\frac{h_I}{R_E}))}\·{\left(\mathrm{UIVE}\right[i]/3.29)}^2---\left(4\right)$

Other component can allow it equal data in UERE table of Galileo system definition:

$\left({\mathrm{\σ}}_{\mathrm{air}}^2\right[i]+{\mathrm{\σ}}_{\mathrm{tropo}}^2[i\left]\right)={\mathrm{\σ}}_{u,L,\mathrm{Galileo}}^2\left[i\right]---\left(5\right)$

Perhaps adopt the experimental formula of following two parameters to calculate:

${\mathrm{\σ}}_{\mathrm{air}}^2\left[i\right]={(0.16+0.23\·e^{\frac{\mathrm{EL}\left[i\right]}{19.6}})}^2---\left(6\right)$

${\mathrm{\σ}}_{\mathrm{tropo}}^2\left[i\right]={\left(0.12\frac{1.001}{\sqrt{0.002001+{\sin }^2\mathrm{EL}\left[i\right]}}\right)}^2---\left(7\right)$

Finally, it is as follows to obtain the variance computing formula of the total pseudorange deviation of gps satellite:

${\mathrm{\σ}}_{u,\mathrm{RX}}^2\left[i\right]={\mathrm{\σ}}_{\mathrm{SISA},\mathrm{GPS}}^2\left[i\right]+{\mathrm{\σ}}_{u,L,\mathrm{GPS}}^2\left[i\right]$

$={\mathrm{\σ}}_{\mathrm{UDRE}}^2\left[i\right]+{\mathrm{\σ}}_{\mathrm{UIRE}}^2\left[i\right]+{\mathrm{\σ}}_{\mathrm{air}}^2\left[i\right]+{\mathrm{\σ}}_{\mathrm{tropo}}^2\left[i\right]---\left(8\right)$

5) calculate weighting matrix, according to " total pseudorange deviations of calculating _{U, RX}[i] " calculate weighting matrix W, realize that by being inverted covariance matrix its diagonal entry is:

$\left\{W_{i,i}\right\}=\frac{1}{{\mathrm{\σ}}_{u,\mathrm{RX}}^2\left[i\right]}---\left(9\right)$

6) calculation level bit error matrix, by observing matrix G and weighting matrix W calculation level bit error matrix K, computing formula is:

K＝(G ^TWG) ^-1G ^TW (10)

In the formula, K is that matrix is resolved in the some position of finding the solution, and G is observing matrix, and formula is as follows:

G _i=[cosEl _iSinAz _i-cosEl _iCosAz _i-sinEl _i1]=i of G matrix is capable

W is weighting matrix, realizes that by being inverted covariance matrix its diagonal entry is:

$\left\{W_{i,i}\right\}=\frac{1}{{\mathrm{\σ}}_{u,\mathrm{RX}}^2\left[i\right]};$

7) calculated level and vertical non-fault and error limit value under the failure condition is arranged respectively:

A. the biased difference of the point under the fault-free conditions is calculated

Make M _Topo={ K} _{Submax trix (3, N)}, N is a satellite number, then horizontal non-fault is put the variance of biased difference cloth limit value and is:

${{\mathrm{\ξ}}_{\mathrm{FF}}}^2=\frac{{\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{nn}}^2+{\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{ee}}^2}{2}+\sqrt{{\left(\frac{{\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{nn}}^2-{\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{ee}}^2}{2}\right)}^2+{\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{ne}}^4}$

Wherein,

${\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{nn}}^2={\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{\mathrm{topo}}[1,i]}^2\·({\mathrm{SISA}}_i^2+{\mathrm{\σ}}_{u,L,i}^2)---\left(11\right)$

${\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{ne}}^2=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{\mathrm{topo}}[1,i]\·M_{\mathrm{topo}}[2,i]\·({\mathrm{SISA}}_i^2+{\mathrm{\σ}}_{u,L,i}^2)$

${\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{ee}}^2={\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{\mathrm{topo}}[2,i]}^2\·({\mathrm{SISA}}_i^2+{\mathrm{\σ}}_{u,L,i}^2)$

The variance that vertical non-fault is put biased difference cloth limit value is:

${\mathrm{\σ}}_{u,V,\mathrm{FF}}^2={\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{\mathrm{topo}}[3,i]}^2\·({\mathrm{SISA}}_i^2+{\mathrm{\σ}}_{u,L,i}^2)---\left(12\right)$

In the formula,

σ _{U, V, FF}Be to limit the standard deviation that vertical direction under the fault-free conditions is put biased differential mode type (zero-mean normal state cumulative distribution function).

ξ _FFBe to limit the standard deviation that horizontal direction under the fault-free conditions is put biased differential mode type.

B. the biased difference of the point under the fault condition is calculated

The variance that the restriction horizontal direction is put biased difference cloth is:

${{\mathrm{\ξ}}_{\mathrm{FM}}}^2=\frac{{\mathrm{\σ}}_{u,\mathrm{MF},\mathrm{nn}}^2+{\mathrm{\σ}}_{u,\mathrm{FM},\mathrm{ee}}^2}{2}+\sqrt{{\left(\frac{{\mathrm{\σ}}_{u,\mathrm{FM},\mathrm{nn}}^2-{\mathrm{\σ}}_{u,\mathrm{FM},\mathrm{ee}}^2}{2}\right)}^2+{\mathrm{\σ}}_{u,\mathrm{FM},\mathrm{ne}}^4}$

Wherein,

${\mathrm{\σ}}_{u,\mathrm{FM},\mathrm{nn}}^2={\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{\mathrm{topo}}[1,i]}^2\·({\mathrm{SISA}}_i^2+{\mathrm{\σ}}_{u,L,i}^2)+M_{\mathrm{topo}}{[1,j]}^2\·({\mathrm{SISMA}}_j^2-{\mathrm{SISA}}_j^2)---\left(13\right)$

${\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{ne}}^2=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{\mathrm{topo}}[1,i]\·M_{\mathrm{topo}}[2,i]\·({\mathrm{SISA}}_i^2+{\mathrm{\σ}}_{u,L,i}^2)+M_{\mathrm{topo}}[1,j]\·M_{\mathrm{topo}}[2,j]\·({\mathrm{SISMA}}_j^2-{\mathrm{SISA}}_j^2)$

${\mathrm{\σ}}_{u,\mathrm{FF},\mathrm{ee}}^2={\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{\mathrm{topo}}[2,i]}^2\·({\mathrm{SISA}}_i^2+{\mathrm{\σ}}_{u,L,i}^2)+M_{\mathrm{topo}}{[2,j]}^2\·({\mathrm{SISMA}}_j^2-{\mathrm{SISA}}_j^2)$

The equation that the restriction vertical direction is put biased difference cloth is:

${\mathrm{\σ}}_{u,V,\mathrm{FM}}^2={\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{\mathrm{topo}}[3,i]}^2\·({\mathrm{SISA}}_i^2+{\mathrm{\σ}}_{u,L,i}^2)+M_{\mathrm{topo}}{[3,j]}^2\·({\mathrm{SISMA}}_j^2-{\mathrm{SISA}}_j^2)---\left(14\right)$

In the formula,

σ _{U, V, FM}Be to limit the standard deviation that vertical direction under the fault condition is put biased differential mode type (zero-mean normal state cumulative distribution function).

ξ _FMBe to limit the standard deviation that horizontal direction under the fault condition is put biased differential mode type.

8) according to level and vertical integrity risk under (15) and (16) formula calculating GPS and the Galileo non-failure conditions:

The horizontal integrity risk of non-fault is:

$P_{\mathrm{IntRisk},H,\mathrm{FF}}=e^{-\frac{{\mathrm{HAL}}^2}{2{{\mathrm{\ξ}}_{\mathrm{FF}}}^2}}---\left(15\right)$

The vertical integrity risk of non-fault is:

$P_{\mathrm{IntRisk},V,\mathrm{FF}}=1-\mathrm{erf}\left(\frac{\mathrm{VAL}}{\sqrt{2}\·{\mathrm{\σ}}_{u,V,\mathrm{FF}}}\right),$ Wherein $\mathrm{erf}\left(u\right)=\frac{2}{\sqrt{\mathrm{\π}}}\·\underset{0}{\overset{u}{\∫}}{e}^{-x^2}{d}_x---\left(16\right)$

9) calculate Galileo according to (17) respectively with (18) formula fault level and vertical integrity risk arranged:

Have the horizontal integrity risk of fault to be:

$P_{\mathrm{IntRisk},H,\mathrm{FM}}=1-{\mathrm{\χ}}_{2,{\mathrm{\δ}}_{u,H}}^2\mathrm{cdf}\left(\frac{{\mathrm{HAL}}^2}{{{\mathrm{\ξ}}_{\mathrm{FM}}}^2}\right)$

Wherein,

$\left(\begin{array}{c}{\mathrm{\μ}}_{u,n}\\ {\mathrm{\μ}}_{u,e}\end{array}\right)=\left(\begin{array}{c}\left|M_{\mathrm{topo}}\right[1,j]\·b_j|\\ \left|M_{\mathrm{topo}}\right[2,j]\·b_j|\end{array}\right),b_j={\mathrm{TH}}_j$

${\mathrm{\δ}}_{u,H}=\left(\begin{array}{cc}{\mathrm{\μ}}_{u,n}& {\mathrm{\μ}}_{u,e}\end{array}\right)\·\left[\begin{array}{cc}{{\mathrm{\ξ}}_{\mathrm{FM}}}^2& 0\\ 0& {{\mathrm{\ξ}}_{\mathrm{FM}}}^2\end{array}\right]\·\left(\begin{array}{c}{\mathrm{\μ}}_{u,n}\\ {\mathrm{\μ}}_{u,e}\end{array}\right)---\left(17\right)$

${\mathrm{\χ}}_{2,\mathrm{\δ}}^2\mathrm{cdf}\left(x\right)=\underset{0}{\overset{x}{\∫}}{\mathrm{\χ}}_{2,\mathrm{\δ}}^2\mathrm{pdf}\left(t\right)\mathrm{dt}$

${\mathrm{\χ}}_{2,\mathrm{\δ}}^2\mathrm{pdf}\left(x\right)=\frac{1}{2}{e}^{-\frac{1}{2}(x+\mathrm{\δ})}\·\underset{j=0}{\overset{\∞}{\mathrm{\Σ}}}\frac{x^j{\mathrm{\δ}}^j}{2^{2j}\·{(j!)}^2}$

Have the vertical integrity risk of fault to be:

$P_{\mathrm{IntRisk},V,\mathrm{FM}}=\frac{1}{2}\·\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{P}_{\mathrm{fail},{\mathrm{sat}}_j}\·((1-\mathrm{erf}\left(\frac{\mathrm{VAL}+{\mathrm{\μ}}_{u,V}}{\sqrt{2}\·{\mathrm{\σ}}_{u,V,\mathrm{FM}}}\right))+(1-\mathrm{erf}\left(\frac{\mathrm{VAL}-{\mathrm{\μ}}_{u,V}}{\sqrt{2}\·{\mathrm{\σ}}_{u,V,\mathrm{FM}}}\right)))---\left(18\right)$

10) calculate two HMI probability that system is total according to (21) formula, namely integrity is offered as a tribute IR:

Total horizontal integrity risk is:

$P_{\mathrm{IntRisk},H}=P_{\mathrm{IntRisk},H,\mathrm{FF}}+\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{P}_{\mathrm{fail},{\mathrm{sat}}_j}\·P_{\mathrm{IntRisk},H,\mathrm{FM}}---\left(19\right)$

Total vertical integrity risk is:

$P_{\mathrm{IntRisk},V}=P_{\mathrm{IntRisk},V,\mathrm{FF}}+\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{P}_{\mathrm{fail},\mathrm{sa}{t}_j}\·P_{\mathrm{IntRisk},V,\mathrm{FM}}---\left(20\right)$

Then synthetic integrity risk is:

$P_{\mathrm{HMI}}(\mathrm{VAL},\mathrm{HAL})=1-\mathrm{erf}\left(\frac{\mathrm{VAL}}{\sqrt{2}\·{\mathrm{\σ}}_{u,V,\mathrm{FF}}}\right)+e^{-\frac{{\mathrm{HAL}}^2}{2{{\mathrm{\ξ}}_{\mathrm{FF}}}^2}}+$

$\frac{1}{2}\·\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{P}_{\mathrm{fail},{\mathrm{sat}}_j}\·((1-\mathrm{erf}\left(\frac{\mathrm{VAL}+{\mathrm{\μ}}_{u,V}}{\sqrt{2}\·{\mathrm{\σ}}_{u,V,\mathrm{FM}}}\right))+(1-\mathrm{erf}\left(\frac{\mathrm{VAL}-{\mathrm{\μ}}_{u,V}}{\sqrt{2}\·{\mathrm{\σ}}_{u,V,\mathrm{FM}}}\right)))---\left(21\right)$

$+\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{P}_{\mathrm{fail},{\mathrm{sat}}_j}\·(1-{\mathrm{\χ}}_{2,{\mathrm{\δ}}_{u,H}}^2\mathrm{cdf}\left(\frac{{\mathrm{HAL}}^2}{{{\mathrm{\ξ}}_{\mathrm{FM}}}^2}\right))$

11) calculate user's protected level (xPL) according to (22) formula under single gps system situation, under the dual system situation, calculate user's protected level (xPL) according to (23) formula:

Level under the non-failure conditions is as follows with vertical protected level:

HPL ₀＝k _H·ξ _FF

(22)

VPL ₀＝k _V·σ _u，V，FF

Have fault as a satellite, but the integrity sign is set to " OK ", level is as follows with vertical protected level computing formula:

$\begin{array}{c}{\mathrm{HPL}}_{\mathrm{FM}}=\underset{i_{\mathrm{sat}}}{\max }\left\{\right|\sqrt{M_u{(1,i_{\mathrm{sat}})}^2+M_u{(2,i_{\mathrm{sat}})}^2}\·\mathrm{TH}\left(i_{\mathrm{sat}}\right)|+k_H\·{\mathrm{\ξ}}_{\mathrm{FF}}\}\\ {\mathrm{VPL}}_{\mathrm{FM}}=\underset{i_{\mathrm{sat}}}{\max }\{M_u(3,i_{\mathrm{sat}})\·\mathrm{TH}\left(i_{\mathrm{sat}}\right)+k_V\·{\mathrm{\σ}}_{u,V,\mathrm{FF}}\}\end{array}---\left(23\right)$

Here

k _VAnd k _HIt is the scale factor that the warning limit value may be exceeded under given probability.They are that vertical and horizontal CDF (cumulative density function) model is at σ _V=1 and ξ _H=1 o'clock value.The present invention realizes the assessment of multisystem user integrity by adopting comparatively advanced Galileo system health concept, by the compare of analysis to the integrity result of calculation of single system and multisystem, proved under the multisystem situation, user's positioning result availability significantly improves, and user's integrity is improved to a great extent.

Description of drawings

Fig. 1 is the schematic flow sheet of the multimode user's integrity appraisal procedure based on Galileo system health concept provided by the invention;

Fig. 2 is the integrity synoptic diagram of the multimode user's integrity appraisal procedure based on Galileo system health concept provided by the invention;

Fig. 3-Fig. 6 is with the horizontal protected level HPL and vertical protected level VPL result schematic diagram of wuhn station as subscriber station.

Embodiment

Below in conjunction with specific embodiment and accompanying drawing technical scheme of the present invention is further specified, but its restriction of not opposing:

This kind provided by the invention is based on multimode user's integrity appraisal procedure of Galileo system health concept, and the GPS constellation raw data of IGS website download is mainly adopted in the input of its data, and the GPS integrity data of emulation.The assessment of multimode system integrity needs two parts data as input, and secondly the one, Galileo system health data SISA, SISMA are gps system integrity data UDRE, UIRE.At present, the Galileo system does not build as yet and finishes, therefore, can only be by adopting the GPS raw data, utilize Galiloe system health CALCULATION OF PARAMETERS method to calculate SISA, SISMA, for the integrity appraisal procedure of GPS constellation systems comparative maturity at present, therefore the system health CALCULATION OF PARAMETERS is not furtherd investigate, but the method for employing data simulation, according to the data rule emulation that has summed up integrity parameter UDRE and the UIRE of constellation data and constellation, as the input data of multisystem user integrity appraisal procedure.The GPS integrity data of emulation are changed, become the information with Galileo system health parameter equivalence, recycling Galileo user integrity concept, according to four kinds of inefficacy mechanisms, be that horizontal non-fault, level have fault, vertical non-fault, vertically have under the failure condition, calculate the integrity value-at-risk respectively, again the integrity value-at-risk under four kinds of situations is superposeed, obtain the final user's integrity result of total system.Simultaneously; we also can be by the derivation of equation and conversion; calculate user's protected level of total system; this is to have considered that the satellite that is used for the location has one to have the multisystem user's protected level that calculates under the situation of fault; be to be different from user's protected level concept of supposing based on non-fault on the traditional sense, its result of calculation reliability significantly improves.

As shown in Figure 1, this kind provided by the invention mainly may further comprise the steps based on multimode user's integrity appraisal procedure of Galileo system health concept:

1) obtain navigation information, at first determine satellite position vector (GPS constellation) according to the broadcast ephemeris data of being downloaded by the IGS website, the navigation information of another one constellation obtains according to Galileo constellation systems parameters simulation;

2) obtain navigational solution, under the normal condition, this value should be determined by broadcast ephemeris, observation data, weather data that receiver receives, adopts the wuhn station of known exact position coordinate as subscriber station among the present invention;

3) calculating observation matrix is according to the position vector of two constellation satellites that can observe and the observing matrix G of receiver location vector calculation subscriber station;

4) obtain integrity information, almanac data, observation data, weather data and subscriber station information calculations Galileo system health parameter S ISMA, SISA according to the IGS download, again according to existing rule emulation GPS constellation integrity data UDRE, UIRE, integrity information and UERE table according to two systems calculate every satellite " total pseudorange deviations _{U, RX}[i] ";

5) 5) calculate weighting matrix, according to " total pseudorange deviations of calculating _{U, RX}[i] " calculating weighting matrix W;

6) calculated level and vertical non-fault and error limit value under the failure condition is arranged respectively;

7) according to level and vertical integrity risk under (15) and (16) formula calculating GPS and the Galileo non-failure conditions;

8) calculate Galileo according to (17) respectively with (18) formula fault level and vertical integrity risk are arranged;

9) calculate two HMI probability that system is total according to (21) formula, namely integrity is offered as a tribute IR;

10) calculate user's protected level according to (22) formula under single gps system situation, under the dual system situation, calculate user's protected level according to (23) formula.

In theory, the user determines oneself position according to satellite-signal, is positioning error PE with the difference of its actual position, and positioning error should be less than alarming threshold value.Yet user's actual position can not obtain, and positioning error is unknown number just, and therefore must seek other parameter characterizes integrity.Receiver is estimated positioning error for each position solution continuously according to the error of various error sources, namely protects level (PL).Consider the integrity risk, suitably amplify by probability, so the protection level is always than the big (PL＞PE) of positioning error.Integrity is estimated based on protection level and alarming threshold value.Receiver is estimated the horizontal PL of location protection, and compares with alarming threshold value AL, if warning message then takes place PL＞AL.

When estimating integrity a hypothesis being arranged is PL＞PE, and as shown in Figure 2, the zone on the principal diagonal left side is safe.When PE＜PL＜AL, system can normally use; If PL＞AL in some cases, then system provides warning message, and this moment, system was unavailable.Regional PL＜the PE on principal diagonal right side, the protection level is less than positioning error, and integrity provides misleading information, is unsafe.Though in theory, in the zone of PL＜PE＜AL and AL＜PL＜PE, the result of the integrity information that provides is correct, the horizontal PL＜PE of the protection that provides, thereby have misleading.And be exactly the zone that causes the integrity risk to exist for the zone of PL＜AL＜PE, produce the reason of integrity risk, be that the misleading of PL＜PE caused.

Fig. 3-Fig. 6 stands as subscriber station with wuhn; the horizontal protected level HPL and vertical protected level VPL at this station have been calculated; diamond curve is the protected level result of calculation of single Galileo or single EGNOS system among the figure; the square curve is dual system protected level CALCULATION OF PARAMETERS result; from the curve map as can be seen; the protected level result of dual system is in most cases less than the result of calculation of single system; at Galileo system safety-of-life applications; the index of protection limit value is that horizontal protected level is 12m; vertical protected level is 20m; therefore the overwhelming majority epoch of protected level constantly is in the protection limits; thereby can judge; system under the dual system situation, the availability of positioning result significantly improves.

Each monitoring station integrity risk availability statistics of table 2.

The comparative analysis of table 3. integrity risk

Table 2 has provided the system availability situation that integrity Risk Calculation result judges, also is user's integrity.Find by statistics, under the dual system situation, system's available rate can reach 98.6%, the single system situation is all much smaller than this result, it is because the data of EGNOS are the results according to rule emulation that single EGNOS result is better than single Galielo, comparatively desirable, be True Data and the result of calculation of Galielo system adopts, so a relative result of dual system and single system comparison is paid close attention in this test more.

Table 3 provided randomly draw several groups epoch the data computation result, significantly reduced the integrity value-at-risk under the dual system situation as can be seen, and improved the availability of system, be that user's integrity is improved.

In sum, the result of several tests proves that simultaneously dual system user integrity contrast single system situation has significantly raising, has verified the availability of algorithm, and is significant to the compatible user's of following multisystem integrity assessment.

The present invention also compares analysis with the result of calculation of single system and the result of calculation of multisystem; adopt the integrity analysis software; provided intuitively under the multisystem situation and the single system situation under; the result of vertical and horizontal protected level is in the difference that availability exists, and obtained the conclusion directly perceived that multimode user's integrity appraisal procedure can improve user's integrity.

Below technology contents of the present invention has been done detailed description.For persons skilled in the art, any apparent change of under the prerequisite that does not deviate from the principle of the invention it being done can not exceed the protection domain of the application's claims.

Claims (2)

1. multimode user's integrity appraisal procedure based on Galileo system health concept, it is characterized in that, directly use user's integrity concept of present Galileo two systems, for non-Galileo system, its integrity parameter is done suitable pre-service, be converted into Galileo user's integrity algorithm information available, computing method fusion by the Galileo system calculates integrity risk IR and/or protected level then, when carrying out the integrity analysis, the numerical value change of monitoring integrity risk IR and/or protected level gets final product;

It specifically may further comprise the steps:

1) obtain navigation information, at first determine the satellite position vector of GPS constellation according to the broadcast ephemeris data of being downloaded by the IGS website, the navigation information of another one constellation obtains according to Galileo constellation systems parameters simulation;

2) obtain navigational solution, the broadcast ephemeris that this navigational solution is received by receiver, observation data, weather data are determined;

3) calculating observation matrix, according to the position vector of two constellation satellites that can observe and the observing matrix G of receiver location vector calculation subscriber station, the computing formula of observing matrix G is:

G _i=[cosEl _iSinAz _i-cosEl _iCosAz _i-sinEl _i1]=i of G matrix is capable;

El in the formula _iBe the elevation angle of i satellite, Az _iIt is the position angle of i satellite;

4) obtain integrity information, almanac data, observation data, weather data and subscriber station information calculations Galileo system health parameter S ISMA, SISA according to the IGS download, again according to existing rule emulation GPS constellation integrity data UDRE, UIRE, integrity information and UERE table according to two systems calculate every satellite " total pseudorange deviations _{U, RX}[i] ";

5) calculate weighting matrix, according to " total pseudorange deviations of every satellite of two systems of above-mentioned steps gained _{U, RX}[i] " calculate the weighting matrix W of the whole big system that is formed by two constellation systems;

6) calculation level bit error matrix K is by observing matrix G and weighting matrix W calculation level bit error matrix K;

7) calculated level and vertical non-fault and error limit value under the failure condition is arranged respectively;

8) calculate level and vertical integrity risk under GPS and the Galileo non-failure conditions respectively;

9) calculate Galileo respectively fault level and vertical integrity risk are arranged;

10) calculate two the HMI probability that system is total, i.e. integrity risk IR.

2. the multimode user's integrity appraisal procedure based on Galileo system health concept according to claim 1 is characterized in that, in the described step 8):

The horizontal integrity risk of non-fault is:

$P_{\mathrm{IntRisk},H,\mathrm{FF}}=e^{-\frac{{\mathrm{HAL}}^2}{2{{\mathrm{\ξ}}_{\mathrm{FF}}}^2}}$

The vertical integrity risk of non-fault is:

$P_{\mathrm{IntRisk},V,\mathrm{FF}}=1-\mathrm{erf}\left(\frac{\mathrm{VAL}}{\sqrt{2}\·{\mathrm{\σ}}_{u,V,\mathrm{FF}}}\right),$ Wherein $\mathrm{erf}\left(u\right)=\frac{2}{\sqrt{\mathrm{\π}}}\·\underset{0}{\overset{u}{\∫}}{e}^{-x^2{d}_x;}$

In the formula,

σ _{U, V, FF}Be to limit the standard deviation that vertical direction under the fault-free conditions is put biased differential mode type;

ξ _FFBe to limit the standard deviation that horizontal direction under the fault-free conditions is put biased differential mode type.

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