CN102901971A - Parity vector method-based double-satellite failure recognition method - Google Patents

Abstract

The invention relates to global satellite navigation system receiver autonomous integrity monitoring technology and discloses a parity vector method-based double-satellite failure recognition method, aiming at the problems of false positives and false negatives caused by fault deviation offsetting when the parity vector method is used for recognizing two fault satellites. According to the technical scheme, the parity vector method is used for recognizing one fault satellite; with the fault satellite as the basis, four fault-free satellites are found out, and the information of the fault-free satellites is used for roughly locating, so that the fault satellites can be recognized; the recognized fault satellites are removed, and then the position resolution is carried out again, so that the locating accuracy is improved; therefore, the problems of false positives or false negatives caused by fault deviation offsetting can be avoided. The method solves the problem of the fault deviation offsetting caused by parity vector residual error and realizes the detection and the recognition for a plurality of fault satellites. After the method is used for detecting and recognizing satellite failure, the locating accuracy is improved. The method is mainly used for monitoring the autonomous integrity of a global satellite navigation system receiver.

Description

Double star fault recognition method based on the parity vector method

Technical field

The present invention relates to satellite navigation and location technology, be particularly related to GPS (Global Position System) (Global Navigation Satellite System, GNSS) receiver autonomous integrity monitoring (Receiver Autonomous Integrity Monitoring, RAIM) method.

Background technology

The GNSS receiver must be taken the pseudorange deviation into account to the impact of navigational solution when obtaining navigational solution.The principal element that causes the pseudorange deviation has that larger satellite clock floats, the fault of the incorrect and satellite ingredient of navigation message data, is referred to as satellite failure here.Because system can't guarantee the reaction time to satellite failure, the fast monitored of satellite failure is only carried out at user side so, thereby the receiver autonomous integrity monitoring method occurred.

The satellite mistake that RAIM utilizes redundant distance measuring signal to detect to cause larger deviations.Usually RAIM comprises two functions: fault detect (Fault Detection) and Fault Identification (Fault Identification).Comparatively RAIM method commonly used comprises: Agonists by Distance Comparison Method, least square method and parity vector method.But these methods all are based under the supposed premise of a fault satellites.Along with the overhead satellites number constantly increases, the probability that two or multi-satellite break down simultaneously can not be left in the basket again.

Traditional fault satellites recognition methods can not be directly used in many fault satellites identifications, and not perfect about the recognition methods of many fault satellites.For example, the parity vector method is used for the deviation counteracting of can breaking down when two fault satellites are identified, and brings thus the situation of failing to judge and judging by accident.

The principle of a fault satellites of parity vector method identification is as follows:

The basic observation equation of receiver positioning calculation is:

y＝Hx+e (1)

In the formula (1), y is the residual vector of Pseudo-range Observations, and H is observing matrix, and x is receiver location residual error and receiver clock error to be calculated, and e is the measuring error of Pseudo-range Observations.

When the non-fault satellite exists, think that measuring error e obeys variance and is

Normal distribution; When having fault satellites to exist, deviation appears in the pseudorange of fault satellites, and at this moment, e is Normal Distribution no longer.

When application parity vector method is carried out the fault satellites detection with identification, at first observing matrix H is decomposed into the long-pending of an orthogonal matrix Q and a upper triangular matrix R, even:

H＝QR (2)

Transposed matrix Q with matrix Q ^TPiecemeal:

$Q^T=\left[\begin{array}{c}{Q}_x\\ Q_p\end{array}\right]---\left(3\right)$

In the formula (3), Q _p∈ R ^{(n-4) * n}Be the odd even space matrix, wherein n is number of satellite, Q _xBe Q ^TFront four lines, then:

p＝Q _py＝Q _pe (4)

In the formula (4), p is parity vector.Pseudorange residual sum of squares (RSS) SSE can construct with parity vector p:

SSE＝p ^Tp (5)

When not having fault satellites,

Obeying degree of freedom is the centralization card side distribution of (n-4), namely

When having fault satellites, The card side that obeys decentralization distributes, namely

λ is the decentralization parameter.Therefore, can construct the fault detect judgement amount

${\widehat{\mathrm{\σ}}}_n=\sqrt{\frac{\mathrm{SSE}}{n-4}}---\left(6\right)$

As overall false-alarm probability α ₀Can calculate fault detect thresholding σ after given _{T, n}For:

$\left\{\begin{array}{c}{\mathrm{\σ}}_{T,n}=\frac{{\mathrm{\σ}}_0{T}_n}{\sqrt{n-4}}\\ T_n=\mathrm{icdf}\left({\mathrm{\χ}}^2(1-{\mathrm{\α}}_0,n-4)\right)\end{array}\right.---\left(7\right)$

In the formula (7), icdf is (1-α) fractile that computer card side distributes.

The time think have fault satellites to exist, and then identification fault satellites, otherwise, think the non-fault satellite, the receiver information of current calculating is accurately.The fault detect judgement amount here

With fault detect thresholding σ _{T, n}, be used to carrying out fault detect.

From formula (4) as can be known parity vector p be through Q by observational error e _pProjection gets, and can carry out fault satellites identification with the geometric properties between them.Structure Fault Identification judgement amount:

$r_i=\frac{\left|\right|p{Q}_{p,i}\left|\right|}{\left|\right|Q_{p,i}\left|\right|}---\left(8\right)$

When all satellites during without the pseudorange deviation,

Therefore the false-alarm probability α that works as single satellite ₁Give regularly, can calculate the Fault Identification thresholding:

$T_{r,n}={\mathrm{\σ}}_0{\mathrm{erf}}^{-1}\left(\frac{{\mathrm{\α}}_1}{2n}\right)---\left(9\right)$

In the formula (9), erf (x) is Gauss error function, erf ^-1(x) be its inverse function.Work as r _iGreater than T _rThe time, can judge that i satellite is fault satellites, there is deviation in its pseudorange.After i satellite rejecting, utilize all the other satellites again to position and resolve to improve bearing accuracy.The Fault Identification judgement amount r of formula (8) and formula (9) _iWith Fault Identification thresholding T _{R, n}, be used to carrying out Fault Identification.

Summary of the invention

Technical matters to be solved by this invention, the deviation that can break down when being used for two fault satellites identification for the parity vector method is exactly offset, and brings thus the shortcoming of failing to judge and judging by accident, and a kind of double star fault recognition method based on the parity vector method is provided.

The present invention solve the technical problem, and the technical scheme of employing is that the double star fault recognition method based on the parity vector method comprises step:

(1), from an existing n satellite, reject satellite i, n is receiver visible satellite quantity in the global position system, n 〉=7;

(2), to remaining (n-1) satellite according to the fault detect judgement amount With fault detect thresholding σ _{T, (n-1)}Carry out fault detect, if

Then think to remain non-fault satellite existence in the satellite, detect and finish; Otherwise, carry out fault satellites identification with the parity vector method, according to Fault Identification judgement amount r _iMaximal value r _j=max (r ₁, r ₂..., r _n), satellite j is rejected;

(3), to remaining (n-2) satellite according to the fault detect judgement amount

With fault detect thresholding σ _{T, (n-2)}Carry out fault detect, if

Then confirm satellite i non-fault, make the non-fault number of satellite add one, enter step (4); Otherwise, the combinations of satellites (i that record is rejected _k, j _k) and calculate position and the clock correction x of receiver with least square method _k, forward step (5) to;

(4), judge whether the non-fault number of satellite of current gained reaches 4, if reach 4 rough position and clock correction that then calculate receiver

And from residue (n-4) satellite, identify fault satellites, and again resolve receiver location and clock correction, detect and finish; Otherwise, enter step (5);

(5), make i=i+1, if i＞n, then the non-fault number of satellite is less than 4, at this moment, from the combinations of satellites of rejecting with pseudorange residual error statistic λ _kMinimum value λ _Min=min (λ ₁, λ ₂..., λ _m) corresponding combinations of satellites is as fault satellites, and calculate the receiver location corresponding with this combinations of satellites and clock correction as positioning result, detect and finish; Otherwise return step (1).

Concrete, the fault detect judgement amount

Obtained by following formula:

${\widehat{\mathrm{\σ}}}_{n-1}=\sqrt{\frac{\mathrm{SSE}}{(n-1)-4}}$

Wherein, SSE is the pseudorange residual sum of squares (RSS);

Fault detect thresholding σ _{T, (n-1)}Obtained by following formula:

$\left\{\begin{array}{c}{\mathrm{\σ}}_{T,(n-1)}=\frac{{\mathrm{\σ}}_0{T}_{n-1}}{\sqrt{(n-1)-4}}\\ T_{n-1}=\mathrm{icdf}\left({\mathrm{\χ}}^2(1-\mathrm{\α},(n-1)-4)\right)\end{array}\right.$

Wherein, icdf is (1-α) fractile that computer card side distributes;

Fault Identification judgement amount r _iObtained by following formula:

$r_i=\frac{\left|\right|p{Q}_{p.i}\left|\right|}{\left|\right|Q_{p.i}\left|\right|}.$

Concrete, detect judgement amount

Obtained by following formula:

${\widehat{\mathrm{\σ}}}_{n-2}=\sqrt{\frac{\mathrm{SSE}}{(n-2)-4}}$

Wherein, SSE is the pseudorange residual sum of squares (RSS);

Fault detect thresholding σ _{T, (n-2)}Obtained by following formula:

$\left\{\begin{array}{c}{\mathrm{\σ}}_{T,(n-2)}=\frac{{\mathrm{\σ}}_0{T}_{n-2}}{\sqrt{(n-2)-4}}\\ T_{n-2}=\mathrm{icdf}\left({\mathrm{\χ}}^2(1-\mathrm{\α},(n-2)-4)\right)\end{array}\right.$

Wherein, icdf is (1-α) fractile that computer card side distributes.

Concrete, rough position and clock correction

Obtained by following formula:

$\hat{x}={\left(H_0^T{H}_0\right)}^{-1}{H}_0^T{y}_0$

Wherein, H ₀Be 4 observing matrixes that the non-fault satellite consists of of current gained, Be H ₀Transposed matrix, y ₀Pseudo-range Observations vector for 4 non-fault satellites of current gained.

Concrete, receiver location and clock correction x _kObtained by following formula:

$x_k={\left(H_k^T{H}_k\right)}^{-1}{H}_k^T{y}_k$ k＝1,2,…,N

Wherein, H _kFor having rejected two satellite (i _k, j _k) after the observing matrix that consists of of remaining (n-2) satellite, y _kFor having rejected two satellite (i _k, j _k) after the Pseudo-range Observations vector of remaining (n-2) satellite;

Pseudorange residual error statistic λ _kObtained by following formula:

${\mathrm{\λ}}_k=\underset{\underset{h\≠i,j}{h=1}}{\overset{n}{\mathrm{\Σ}}}{({\mathrm{\ρ}}_h-b_k-\sqrt{{(x_h-x_k)}^2+{(y_h-y_k)}^2+{(z_h-z_k)}^2})}^2.$

The invention has the beneficial effects as follows, solved the fault deviation cancellation problem of parity vector residual error, realized the detection identification of many fault satellites.Detect the identification satellite fault by the present invention, can improve bearing accuracy.

Description of drawings

Fig. 1 is process flow diagram of the present invention.

Embodiment

Below in conjunction with drawings and Examples, describe technical scheme of the present invention in detail.

The present invention is take fault satellites of parity vector method identification as the basis, find out 4 non-fault satellites, then carry out coarse localization with the information of non-fault satellite, and identify thus fault satellites, to re-start again location compute with the raising bearing accuracy after its rejecting, thereby avoid the failing to judge or the erroneous judgement problem of bringing by the counteracting of fault deviation.

Of the present inventionly mainly contain two gordian techniquies, the one, the identification of non-fault satellite take fault satellites of parity vector method identification as the basis, is found out 4 non-fault satellites in order to coarse localization from an existing n satellite; The 2nd, gone out rough position and the clock correction of receiver by the information calculations of 4 non-fault satellites

Wherein

The rough coordinates of receiver,

Receiver clock correction.And by

Calculate the pseudorange residual delta of all the other (n-4) satellites _i, and determine detection threshold according to the false-alarm probability of fault satellites identification, identify fault satellites.

The below elaborates with regard to two gordian techniquies:

1, non-fault satellite recognition principle

If there are two fault satellites to exist, then in n satellite, rejected one by one two satellites with the parity vector method after, if according to the fault detect judgement amount of remaining (n-2) satellite calculating gained still greater than the fault detect thresholding, that is:

First satellite of then rejecting must be the non-fault satellite, do not have deviation in the pseudorange.The principle of identification non-fault satellite can be divided into following two kinds of situations and discuss:

(1) if calculates the fault detect judgement amount of gained still less than the fault detect thresholding, that is: according to remaining (n-2) satellite

The time, in remaining (n-2) satellite, may there be fault satellites or has two fault satellites, but under the effect that the fault deviation is offset, so that

Can't judge in this case whether fault satellites of first satellite of rejecting.

(2) if calculate the fault detect judgement amount of gained still greater than the fault detect thresholding, that is: according to remaining (n-2) satellite

The time, in remaining (n-2) satellite, may there be a fault satellites; Also at this moment fault deviation counteracting is not obvious, has two fault satellites.No matter be which kind of situation, first satellite of rejecting all must be the non-fault satellite, otherwise, in remaining (n-1) satellite, only have a fault satellites to exist, adopt the parity vector method another fault satellites can be identified this moment, thereby

If it should be noted that note:

Be event A; First satellite of rejecting is that the non-fault satellite is event B.

Then discuss for following three propositions:

Proposition 1: if B is A then.This is a wrong proposition, when second satellite of rejecting during also for satellite without reason, has two fault satellites in remaining (n-2) satellite, and the deviation counteracting then if break down this moment Therefore, even if first satellite is the non-fault satellite,

Also might be less than σ _{T (n-2)}

Proposition 2: if

Then

Therefore this proposition also is wrong for proposition 1 converse negative proposition, it also just explanation can not because of

Just judge that two satellites of rejecting are fault satellites.

Proposition 3: if

Then

First satellite of even rejecting be fault satellites then

This proposition is set up, and when first satellite of rejecting is fault satellites, only has a fault satellites in remaining (n-1) satellite, use the parity vector method this satellite can be identified, so the non-fault satellite exists in remaining (n-2) satellite, therefore ${\widehat{\mathrm{\&sigma;}}}_{n-2}<{\mathrm{\&sigma;}}_{T,(n-2)}.$

The method that the present invention identifies the non-fault satellite is mutually converse negative proposition with proposition 3, thereby the correctness of identification non-fault satellite method has been described.

2, fault satellites recognition principle

Can detect 4 non-fault satellites by top method, the information of 4 non-fault satellites just can calculate by the method for least square rough position and the receiver clock correction of receiver thus

Work as acquisition After can the compute pseudo-ranges residual delta _i:

${\mathrm{\&Delta;}}_i=|{\mathrm{\&rho;}}_i-\hat{b}-\sqrt{{(x_i-\hat{x})}^2+{(y_i-\hat{y})}^2+{(z_i-\hat{z})}^2}---\left(10\right)$

When there is not the pseudorange deviation in satellite i, the pseudorange observational error

Otherwise, e _iBe not 0 Gaussian distribution with obeying average.Therefore, as single satellite false-alarm probability α ₁To regularly having:

$P({\mathrm{\&Delta;}}_i>T_{\mathrm{\&Delta;}})={\&Integral;}_{T_{\mathrm{\&Delta;}}}^{+\&infin;}\frac{1}{\sqrt{2\mathrm{\&pi;}}{\mathrm{\&sigma;}}_0}\exp (-\frac{{{\mathrm{\&Delta;}}_i}^2}{2{\mathrm{\&sigma;}}^2})d{\mathrm{\&Delta;}}_i=1-\frac{{\mathrm{\&alpha;}}_1}{2}---\left(11\right)$

Through type (11) can calculate fault satellites identification thresholding T _ΔΔ _iWith T _ΔAll identify for fault satellites.

Work as Δ _i＞T _ΔThe time can judge that satellite i is fault satellites, can realize thus the identification of two fault satellites.

In addition, when fault satellites during more than, since the cause that the fault deviation is offset, the Fault Identification judgement amount r of parity vector method _i(i=1,2 ..., maximal value r n) _j=max (r ₁, r ₂..., r _n), r _MaxCorresponding satellite j may not be the fault satellite.And from reducing the angle of calculated amount, when realizing, the rejecting of first satellite can be adopted the method for rejecting one by one, when second fault satellites of identification, re-uses the parity vector method.

From non-fault satellite recognition principle as can be known, the present invention is mainly by the fault detect judgement amount behind two satellites of rejecting

First satellite that decides rejecting be fault satellites whether.Calculating The time, need to satisfy n-2 〉=5, therefore, only have when number of satellite and just can carry out the double star fault detect during more than or equal to 7 (n 〉=7).Yet less and fault deviation is offset when serious when number of satellite, even if all satellites are all searched one time, the non-fault number of satellite that obtains may be still less than 4.Can not calculate the coarse information of receiver this moment, thereby can't carry out fault satellites identification.

The non-fault number of satellite is right less than 4 o'clock needs The time all satellites of rejecting combination (i _k, j _k) test.Corresponding every kind of fault satellites combination can be calculated one group receiver coordinate and clock correction x with residue (n-2) satellite by least square method _k=(x _k, y _k, z _k, b _k) k=1,2 ..., m, m is

Corresponding all combinations of satellites numbers.

Equally according to x _kCan calculate the pseudorange residual error statistic λ of residue (n-2) satellite _k, as decision statistics:

${\mathrm{\&lambda;}}_k=\underset{\underset{h\&NotEqual;i,j}{h=1}}{\overset{n}{\mathrm{\&Sigma;}}}{({\mathrm{\&rho;}}_h-b_k-\sqrt{{(x_h-x_k)}^2+{(y_h-y_k)}^2+{(z_h-z_k)}^2})}^2---\left(12\right)$

If λ _l=min (λ ₁, λ ₂..., λ _m), (i then _l, j _l) for the fault satellites combination, position with the residue satellite again after the rejecting and resolve, obtain the receiver exact position.

Embodiment

Fig. 1 has provided flow process of the present invention.Its concrete grammar is as follows:

(1), from an existing n satellite, reject satellite i, i is 1 when initial;

(2), remaining (n-1) satellite is carried out fault detect, the fault detect judgement amount

${\widehat{\mathrm{\&sigma;}}}_{n-1}=\sqrt{\frac{\mathrm{SSE}}{(n-1)-4}}---\left(13\right)$

Calculate the fault detect thresholding σ of (n-1) satellite _{T, (n-1)}:

$\left\{\begin{array}{c}{\mathrm{\&sigma;}}_{T,(n-1)}=\frac{{\mathrm{\&sigma;}}_0{T}_{n-1}}{\sqrt{(n-1)-4}}\\ T_{n-1}=\mathrm{icdf}\left({\mathrm{\&chi;}}^2(1-\mathrm{\&alpha;},(n-1)-4)\right)\end{array}\right.---\left(14\right)$

If Then think to remain non-fault satellite existence in the satellite, detect and finish; Otherwise, carry out fault satellites identification with the parity vector method, calculate Fault Identification judgement amount r _i:

$r_i=\frac{\left|\right|p{Q}_{p.i}\left|\right|}{\left|\right|Q_{p.i}\left|\right|}---\left(15\right)$

Try to achieve r _i(i=1,2 ..., maximal value r n) _j=max (r ₁, r ₂..., r _n), will enter step (3) after the satellite j rejecting;

(3), remaining (n-2) satellite is carried out fault detect, the fault detect judgement amount of calculating (n-2) satellite:

${\widehat{\mathrm{\&sigma;}}}_{n-2}=\sqrt{\frac{\mathrm{SSE}}{(n-2)-4}}---\left(16\right)$

Wherein, SSE is the pseudorange residual sum of squares (RSS);

Barrier detection threshold σ _{T, (n-2)}Obtained by following formula:

$\left\{\begin{array}{c}{\mathrm{\&sigma;}}_{T,(n-2)}=\frac{{\mathrm{\&sigma;}}_0{T}_{n-2}}{\sqrt{(n-2)-4}}\\ T_{n-2}=\mathrm{icdf}\left({\mathrm{\&chi;}}^2(1-\mathrm{\&alpha;},(n-2)-4)\right)\end{array}\right.---\left(17\right)$

Wherein, icdf is (1-α) fractile that computer card side distributes.

If

Then confirm satellite i non-fault, make the non-fault number of satellite add one, enter step (4); Otherwise, the combinations of satellites (i that record is rejected _k, j _k) and calculate position and the clock correction x of receiver with least square method _k,

K=1,2 ..., N, wherein, H _kFor having rejected two satellite (i _k, j _k) after the observing matrix that consists of of remaining (n-2) satellite, y _kFor having rejected two satellite (i _k, j _k) after the Pseudo-range Observations vector of remaining (n-2) satellite.Forward step (5) to;

(4), judge whether the non-fault number of satellite of current gained reaches 4, if reach 4 rough position and clock correction that then calculate receiver

$\hat{x}={\left(H_0^T{H}_0\right)}^{-1}{H}_0^T{y}_0---\left(18\right)$

In the formula (18), H ₀Be 4 observing matrixes that the non-fault satellite consists of of current gained, Be H ₀Transposed matrix, y ₀Pseudo-range Observations vector for 4 non-fault satellites of current gained.

Obtain After, can come the compute pseudo-ranges residual delta according to formula (10) and formula (11) _iWith fault satellites identification thresholding T _Δ, and from remaining (n-4) satellite, identify fault satellites, and again resolve receiver location and clock correction information, detect and finish; Otherwise enter step (5);

(5), make i=i+1, if i＞n, then the non-fault number of satellite is less than 4, at this moment, according to x _kObtain pseudorange residual error statistic λ _k, from the combinations of satellites of rejecting with pseudorange residual error statistic λ _kMinimum value λ _Min=min (λ ₁, λ ₂..., λ _m) corresponding combinations of satellites is as fault satellites, and calculate the receiver location corresponding with this combinations of satellites and clock correction as positioning result, detect and finish; Otherwise return step (1).

Claims (5)

1. based on the double star fault recognition method of parity vector method, comprise step:

(1), from an existing n satellite, reject satellite i, n is receiver visible satellite quantity in the global position system, n 〉=7;

(2), to remaining (n-1) satellite according to the fault detect judgement amount

With fault detect thresholding σ _{T, (n-1)}Carry out fault detect, if

Then think to remain non-fault satellite existence in the satellite, detect and finish; Otherwise, carry out fault satellites identification with the parity vector method, according to Fault Identification judgement amount r _iMaximal value r _j=max (r ₁, r ₂, r _n), satellite j is rejected;

(3), to remaining (n-2) satellite according to the fault detect judgement amount

With fault detect thresholding σ _{T, (n-2)}Carry out fault detect, if

Then confirm satellite i non-fault, make the non-fault number of satellite add one, enter step (4); Otherwise, the combinations of satellites (i that record is rejected _k, j _k) and calculate position and the clock correction x of receiver with least square method _k, forward step (5) to;

(4), judge whether the non-fault number of satellite of current gained reaches 4, if reach 4 rough position and clock correction that then calculate receiver

And from residue (n-4) satellite, identify fault satellites, and again resolve receiver location and clock correction, detect and finish; Otherwise, enter step (5);

(5), make i=i+1, if i＞n, then the non-fault number of satellite is less than 4, at this moment, from the combinations of satellites of rejecting with pseudorange residual error statistic λ _kMinimum value λ _Min=min (λ ₁, λ ₂..., λ _m) corresponding combinations of satellites is as fault satellites, and calculate the receiver location corresponding with this combinations of satellites and clock correction as positioning result, detect and finish; Otherwise return step (1).

2. the double star fault recognition method based on the parity vector method according to claim 1 is characterized in that the fault detect judgement amount

Obtained by following formula:

${\widehat{\mathrm{\&sigma;}}}_{n-1}=\sqrt{\frac{\mathrm{SSE}}{(n-1)-4}}$

Wherein, SSE is the pseudorange residual sum of squares (RSS);

Fault detect thresholding σ _{T, (n-1)}Obtained by following formula:

$\left\{\begin{array}{c}{\mathrm{\&sigma;}}_{T,(n-1)}=\frac{{\mathrm{\&sigma;}}_0{T}_{n-1}}{\sqrt{(n-1)-4}}\\ T_{n-1}=\mathrm{icdf}\left({\mathrm{\&chi;}}^2(1-\mathrm{\&alpha;},(n-1)-4)\right)\end{array}\right.$

Wherein, icdf is (1-α) fractile that computer card side distributes;

Fault Identification judgement amount r _iObtained by following formula:

$r_i=\frac{\left|\right|p{Q}_{p.i}\left|\right|}{\left|\right|Q_{p.i}\left|\right|}.$

3. the double star fault recognition method based on the parity vector method according to claim 1 is characterized in that, detects judgement amount

Obtained by following formula:

${\widehat{\mathrm{\&sigma;}}}_{n-2}=\sqrt{\frac{\mathrm{SSE}}{(n-2)-4}}$

Wherein, SSE is the pseudorange residual sum of squares (RSS);

Fault detect thresholding σ _{T, (n-2)}Obtained by following formula:

$\left\{\begin{array}{c}{\mathrm{\&sigma;}}_{T,(n-2)}=\frac{{\mathrm{\&sigma;}}_0{T}_{n-2}}{\sqrt{(n-2)-4}}\\ T_{n-2}=\mathrm{icdf}\left({\mathrm{\&chi;}}^2(1-\mathrm{\&alpha;},(n-2)-4)\right)\end{array}\right.$

Wherein, icdf is (1-α) fractile that computer card side distributes.

4. the double star fault recognition method based on the parity vector method according to claim 1 is characterized in that rough position and clock correction Obtained by following formula:

$\hat{x}={\left(H_0^T{H}_0\right)}^{-1}{H}_0^T{y}_0$

Wherein, H ₀Be 4 observing matrixes that the non-fault satellite consists of of current gained,

Be H ₀Transposed matrix, y ₀Pseudo-range Observations vector for 4 non-fault satellites of current gained.

5. the double star fault recognition method based on the parity vector method according to claim 1 is characterized in that, receiver location and clock correction x _kObtained by following formula:

$x_k={\left(H_k^T{H}_k\right)}^{-1}{H}_k^T{y}_k$ k＝1,2,…,N

Wherein, H _kFor having rejected two satellite (i _k, j _k) after the observing matrix that consists of of remaining (n-2) satellite, y _kFor having rejected two satellite (i _k, j _k) after the Pseudo-range Observations vector of remaining (n-2) satellite;

Pseudorange residual error statistic λ _kObtained by following formula:

${\mathrm{\&lambda;}}_k=\underset{\underset{h\&NotEqual;i,j}{h=1}}{\overset{n}{\mathrm{\&Sigma;}}}{({\mathrm{\&rho;}}_h-b_k-\sqrt{{(x_h-x_k)}^2+{(y_h-y_k)}^2+{(z_h-z_k)}^2})}^2.$

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