CN102565814A - Method for evaluating signal accuracy and positioning service availability of satellite navigation system - Google Patents

Abstract

The invention provides a method for evaluating the signal accuracy and positioning service availability of a satellite navigation system. The method comprises the following steps of: downloading data of a broadcast ephemeris file and a precise ephemeris from websites of an international global positioning system (GPS) service (IGS) organization; according to description of a global navigation satellite system (GNSS) interface file, computing satellite approximate coordinates and satellite approximate clock correction by using the broadcast ephemeris file; computing satellite precise coordinates and satellite precise clock correction by using the precise ephemeris file; computing a satellite coordinate error and a satellite clock correction error per minute; computing a user range error of a grid point at the t-th moment; computing the accuracy of the user range error of the grid point, and counting the accuracy of the user range errors of global satellite navigation systems; computing a horizontal positioning accuracy factor and a vertical positioning accuracy factor of the grid point at the t-th moment; and computing horizontal positioning accuracy and horizontal positioning service availability, and computing vertical positioning accuracy and vertical positioning service availability. The method can be applied to various kinds of satellite navigation systems.

Description

The signal accuracy of satellite navigation system and the appraisal procedure of location service availability

Technical field

The present invention relates to a kind of appraisal procedure of signal accuracy and location service availability of satellite navigation system, belong to the satellite navigation technical field.

Background technology

Progressively development along with the satellite navigation system technology; Following GPS (the Global Positioning System that the U.S. is not only arranged; Be called for short: GPS) navigational system also has Galileo (Galileo) navigational system in Muscovite GLONASS (GLONASS) navigational system, Europe and the triones navigation system of China.Satellite navigation signals precision and location service availability that different satellite navigation systems provides are not quite similar.Satellite navigation system comprises space constellation systems, ground control system and client terminal system.As far as user location, the satellite navigation signals performance that the space constellation systems provides has determined user's basic navigation positioning performance with communication environments error and receiver user performance.Wherein, the satellite navigation signals precision is the unique part that can control and guarantee of satellite navigation system ISP.The user is located availability, and different service availabilities has determined whether satellite navigation can be used for the certain applications field, and is the basis of exploitation respective satellite enhanced system.For signal accuracy and the service availability of assessing different satellite navigation systems, be necessary to develop a kind of unified appraisal procedure.

Summary of the invention

The present invention provides a kind of appraisal procedure of signal accuracy and location service availability of satellite navigation system, to realize the unified assessment to different satellite navigation systems.

One aspect of the present invention provides a kind of appraisal procedure of signal accuracy and location service availability of satellite navigation system, comprising:

Download the data of broadcast ephemeris file and the data of precise ephemeris file from the website of IGS tissue;

With reference to the description of GNSS interface document, use said broadcast ephemeris file to calculate satellite rough coordinates (X _kY _kZ _k) and satellite summary clock correction Δ t _Sv

Use said precise ephemeris file to calculate satellite precise coordinate (X _p, Y _p, Z _p) and satellite precise clock correction Δ t _{Sv, p}

Calculate co-ordinates of satellite error (the Δ X=X of each minute _k-X _p, Δ Y=Y _k-Y _p, Δ Z=Z _k-Z _p) and satellite clock difference error delta t=Δ t _Sv-Δ t _{Sv, p}

Calculate t net point user ranging errors constantly ${\mathrm{URE}}_{\mathrm{Grid},t}=({\mathrm{\Δ}}_x^{\mathrm{Rs}}\·\mathrm{\Δ\; X}+{\mathrm{\Δ}}_y^{\mathrm{Rs}}\·\mathrm{\Δ\; Y}+{\mathrm{\Δ}}_z^{\mathrm{Rs}}\·\mathrm{\Δ\; Z})-\mathrm{C\Δ\; t};$

Grid points user ranging errors precision

also is directed against the whole world, the user ranging errors precision

of statistics satellite navigation system

Calculate the t horizontal location dilution of precision of net point constantly

With the perpendicular positioning dilution of precision $\mathrm{VDOP}=\sqrt{g_{33}^s};$

Calculate the t horizontal location precision HACCU at net point place constantly _{Grid, t}=1.96HDOP*RMS _Grid, and the horizontal location service availability performance of grid points satellite navigation system ${\mathrm{Avail}}_{\mathrm{Hor},\mathrm{Grid}}=\frac{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}({\mathrm{HACCU}}_{\mathrm{Grid},t}<17)}{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}\left(H_{\mathrm{Grid},t}\right)}\&times;100\%;$

Calculate the t perpendicular positioning precision VACCU at net point place constantly _{Grid, t}=1.96VDOP*RMS _Grid, and the perpendicular positioning service availability performance of grid points satellite navigation system ${\mathrm{Avail}}_{\mathrm{Ver},\mathrm{Grid}}=\frac{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}({\mathrm{VACCU}}_{\mathrm{Grid},t}<37)}{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}\left({\mathrm{VACCU}}_{\mathrm{Grid},t}\right)}\&times;100\%.$

The present invention provides a kind of signal accuracy of satellite navigation system and the apparatus for evaluating of location service availability on the other hand, comprising:

Data download module is used for downloading broadcast ephemeris file data and precise ephemeris file data from the website of IGS tissue;

The summary computing module is used for the description with reference to the GNSS interface document, uses said broadcast ephemeris file to calculate satellite rough coordinates (X _kY _kZ _k) and satellite summary clock correction Δ t _Sv

Accurate computing module is used to use said precise ephemeris file to calculate satellite precise coordinate (X _p, Y _p, Z _p) and satellite precise clock correction Δ t _{Sv, p}

The error computing module is used to calculate co-ordinates of satellite error (the Δ X=X of each minute _k-X _p, Δ Y=Y _k-Y _p, Δ Z=Z _k-Z _p) and satellite clock difference error delta t=Δ t _Sv-Δ t _{Sv, p}, and calculate t net point user ranging errors constantly ${\mathrm{URE}}_{\mathrm{Grid},t}=({\mathrm{\&Delta;}}_x^{\mathrm{Rs}}\&CenterDot;\mathrm{\&Delta;\; X}+{\mathrm{\&Delta;}}_y^{\mathrm{Rs}}\&CenterDot;\mathrm{\&Delta;\; Y}+{\mathrm{\&Delta;}}_z^{\mathrm{Rs}}\&CenterDot;\mathrm{\&Delta;\; Z})-\mathrm{C\&Delta;\; t};$

The precision operations module; Be used for grid points user ranging errors precision

and, add up the user ranging errors precision

of satellite navigation system to the whole world

Factor computing module is used to calculate t the horizontal location dilution of precision

and the perpendicular positioning dilution of precision

of net point constantly

Horizontal performance module is used to calculate the t horizontal location precision HACCU at net point place constantly _{Grid, t}=1.96HDOP*RMS _Grid, and the horizontal location service availability performance of grid points satellite navigation system ${\mathrm{Avail}}_{\mathrm{Hor},\mathrm{Grid}}=\frac{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}({\mathrm{HACCU}}_{\mathrm{Grid},t}<17)}{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}\left(H_{\mathrm{Grid},t}\right)}\&times;100\%;$

The Vertical performance module is used to calculate the t perpendicular positioning precision VACCU at net point place constantly _{Grid, t}=1.96VDOP*RMS _Grid, and the perpendicular positioning service availability performance of grid points satellite navigation system ${\mathrm{Avail}}_{\mathrm{Ver},\mathrm{Grid}}=\frac{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}({\mathrm{VACCU}}_{\mathrm{Grid},t}<37)}{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}\left({\mathrm{VACCU}}_{\mathrm{Grid},t}\right)}\&times;100\%.$

The present invention is according to user's location requirement; The actual navigation data that provides according to satellite navigation system and the practical layout of satellite constellation; Propose the order of accuarcy of assessment navigation data and the feasible program of location service availability, gone for various satellite navigation system.

Description of drawings

Fig. 1 is the process flow diagram of appraisal procedure embodiment of signal accuracy and the location service availability of satellite navigation system according to the invention;

Fig. 2 is the particular flow sheet of step 120 shown in Figure 1;

Fig. 3 is the structural representation of apparatus for evaluating embodiment of signal accuracy and the location service availability of satellite navigation system according to the invention;

Fig. 4 is the concrete structure synoptic diagram of accurate computing module 30 shown in Figure 3.

Embodiment

Fig. 1 is the process flow diagram of appraisal procedure embodiment of the signal accuracy of satellite navigation system according to the invention, and is as shown in the figure, comprises the steps:

Step 110 is downloaded broadcast ephemeris file data and precise ephemeris file data from the website of IGS tissue.

Wherein, said IGS tissue is meant international GPS service organization, is the office of international organization that instructs various countries' satellite navigation technical development; Particularly, (File Transfer Protocol is called for short: FTP) realize downloading can to pass through FTP.

After the download, can also delete the unhealthy data in the said broadcast ephemeris file data, for example; IODC (Issue of Data; Clock is called for short: clock data length of time) with IODE (Issue of Data, Ephemeris; Being called for short: almanac data length of time) inconsistent data, satellite health word are not that (User Range Accuracy is called for short: the distance accuracy index) more than or equal to 48 meters data etc. for 0 data, satellite URA.

Step 120 with reference to the description of GNSS interface document, uses said broadcast ephemeris file to calculate satellite rough coordinates (X _kY _kZ _k) and satellite summary clock correction Δ t _Sv

Wherein, said GNSS interface is meant GLONASS (Global Navigation Satellite System) interface; Said broadcast ephemeris file comprises the satellite ephemeris parameter shown in the table 1:

Table 1

Step 130 uses said precise ephemeris file to calculate satellite precise coordinate (X _p, Y _p, Z _p) and satellite precise clock correction Δ t _{Sv, p}

Particularly; (Standard Product 3 Orbit Format, be called for short: standard trajectory product form) the precise ephemeris file has provided corresponding GPS satellite precise coordinate and satellite precise clock correction constantly according to certain hour interval (for example 15 minutes) to the SP3 that announce the website of IGS tissue.The customized justice of the performance evaluation system time interval (for example 1 minute) is calculated the user ranging errors in the corresponding moment.If the time interval that the self-defined time interval of performance evaluation system and SP3 precise ephemeris file are given is inconsistent, can pass through Lagrange's interpolation, calculate the satellite precise coordinate and the satellite precise clock correction in the moment of selecting by the precise ephemeris file.Generally, can select three days precise ephemeris file to calculate central one day High Precision Satellite Ephemeris for borderline interpolation error of reduction time.The exponent number of Lagrange's interpolation can be self-defined.With seven rank Lagrange's interpolations is example, and a certain moment Lagrange's interpolation formula form is:

$L_7\left(x\right)=\underset{i=0}{\overset{7}{\mathrm{\&Sigma;}}}\underset{j\&NotEqual;i}{\overset{7}{\underset{j=0}{\mathrm{\&Pi;}}}}\frac{x-x_j}{x_i-x_j}{y}_i$

The co-ordinates of satellite that the precise ephemeris file provides is the satellite center-of-mass coordinate, and the co-ordinates of satellite that broadcast ephemeris provides is a satellite phase center coordinate.The phase center deviation data that uses IGS regularly to announce, the satellite center-of-mass coordinate that Lagrange's interpolation is calculated is converted into satellite phase center coordinate under the solid coordinate system of star, and this satellite phase center coordinate is satellite precise coordinate (X _p, Y _p, Z _p); Calculate the satellite precise clock correction Δ t of any time according to Lagrange's interpolation formula according to the precise ephemeris file data _{Sv, p}

Step 140 is calculated co-ordinates of satellite error (the Δ X=X of each minute _k-X _p, Δ Y=Y _k-Y _p, Δ Z=Z _k-Z _p) and satellite clock difference error delta t=Δ t _Sv-Δ t _{Sv, p}

Step 150 is calculated t net point user ranging errors constantly.

Particularly, the whole world is divided into the grid of 5 degree x5 degree,, calculates of the error projection of co-ordinates of satellite error to respective grid points according to the coordinate of each net point.To each net point, in computation process, only consider the satellite of the elevation angle more than 5 degree.Each user ranging errors constantly of each grid is calculated according to 1 minute time interval, continued 24 hours.

The hypothetical trellis point coordinate is X _u, Y _u, Z _u, the coordinate vector of grid points to satellite is:

${\mathrm{\&Delta;}}_y^{\mathrm{rs}}=(X_k-X_u)/\sqrt{{\mathrm{\&Delta;}}_x^{\mathrm{rs}}\&CenterDot;{\mathrm{\&Delta;}}_x^{\mathrm{rs}}+{\mathrm{\&Delta;}}_y^{\mathrm{rs}}\&CenterDot;{\mathrm{\&Delta;}}_y^{\mathrm{rs}}+{\mathrm{\&Delta;}}_z^{\mathrm{rs}}\&CenterDot;{\mathrm{\&Delta;}}_z^{\mathrm{rs}}}$

${\mathrm{\&Delta;}}_x^{\mathrm{rs}}=(Y_k-Y_u)/\sqrt{{\mathrm{\&Delta;}}_x^{\mathrm{rs}}\&CenterDot;{\mathrm{\&Delta;}}_x^{\mathrm{rs}}+{\mathrm{\&Delta;}}_y^{\mathrm{rs}}\&CenterDot;{\mathrm{\&Delta;}}_y^{\mathrm{rs}}+{\mathrm{\&Delta;}}_z^{\mathrm{rs}}\&CenterDot;{\mathrm{\&Delta;}}_z^{\mathrm{rs}}}$

${\mathrm{\&Delta;}}_z^{\mathrm{rs}}=(Z_k-Z_u)/\sqrt{{\mathrm{\&Delta;}}_x^{\mathrm{rs}}\&CenterDot;{\mathrm{\&Delta;}}_x^{\mathrm{rs}}+{\mathrm{\&Delta;}}_y^{\mathrm{rs}}\&CenterDot;{\mathrm{\&Delta;}}_y^{\mathrm{rs}}+{\mathrm{\&Delta;}}_z^{\mathrm{rs}}\&CenterDot;{\mathrm{\&Delta;}}_z^{\mathrm{rs}}}$

Then this net point place constantly the user ranging errors during t be:

${\mathrm{URE}}_{\mathrm{grid},t}=({\mathrm{\&Delta;}}_x^{\mathrm{rs}}\&CenterDot;\mathrm{\&Delta;X}+{\mathrm{\&Delta;}}_y^{\mathrm{rs}}\&CenterDot;\mathrm{\&Delta;Y}+{\mathrm{\&Delta;}}_z^{\mathrm{rs}}\&CenterDot;\mathrm{\&Delta;Z})-\mathrm{c\&Delta;t}.$

Step 160, grid points user ranging errors precision, and to the whole world, the user ranging errors precision of statistics satellite navigation system.

Particularly, at first to delete the exceptional value that does not meet the gps signal standard.Deletion URE is greater than the sample of a certain thresholding, and thresholding is taken as 25 meters according to the gps signal normative choice.Then to each net point; User ranging errors sample in all satellites that observe according to net point 24 hours; The statistics net point the user ranging errors precision be

to the whole world, the user ranging errors precision of adding up satellite navigation system is:

Step 170 is calculated t the horizontal location dilution of precision

and the perpendicular positioning dilution of precision of net point constantly

Particularly, at first, calculate by the observing matrix of net point to all satellites in view:

$H=\left[\begin{array}{cccc}{l}_1& m_1& n_1& 1\\ l_2& m_2& {\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000120732580000011.png"\; state="\{\{state\}\}">n</figure-callout>}}_2& 1\\ .& .& .& .\\ .& .& .& .\\ .& .& .& .\\ l_n& m_n& n_n& 1\end{array}\right]$

Wherein, l _j, m _jAnd n _jThe direction cosine of the unit vector of j satellite are pointed in expression by apparent position; Calculate G=(H then ^TH) ^-1, and suppose that the representation in components of G does,

$G=\left[\begin{array}{cccc}{g}_{11}& g_{12}& g_{13}& g_{14}\\ g_{12}& g_{22}& g_{23}& g_{24}\\ g_{13}& g_{23}& g_{33}& g_{34}\\ g_{14}& g_{24}& g_{34}& g_{44}\end{array}\right]$

Calculating G matrix is based on ECEF (Earth-Centered Earth-Fixed, be called for short: the ground heart is solid) coordinate system above, need convert local ENU (East North Upper into; Be called for short: northeast is high) coordinate system; After being transformed into local ENU coordinate system, each component of G matrix becomes

$g_{11}^s=g_{11}{\sin }^2\mathrm{\&phi;}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000120732580000011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&lambda;}+g_{22}{\sin }^2\mathrm{\&phi;}{\sin }^2\mathrm{\&lambda;}+{\mathrm{<figure-callout\; id="33"\; label="g"\; filenames="HDA0000120732580000032.png"\; state="\{\{state\}\}">g</figure-callout>}}_{33}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000120732580000011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&phi;}+$

$2g_{12}{\sin }^2\mathrm{\&phi;}\sin \mathrm{\&lambda;}\cos \mathrm{\&lambda;}-2g_{13}\sin \mathrm{\&phi;}\cos \mathrm{\&phi;}\cos \mathrm{\&lambda;}-2g_{23}\sin \mathrm{\&phi;}\cos \mathrm{\&phi;}\sin \mathrm{\&lambda;}$

$g_{22}^s=g_{11}{\sin }^2\mathrm{\&lambda;}-2g_{12}\sin \mathrm{\&lambda;}\cos \mathrm{\&lambda;}+g_{22}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000120732580000011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&lambda;}$

$g_{33}^s=g_{11}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000120732580000011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&phi;}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000120732580000011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&lambda;}+g_{22}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000120732580000011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&phi;}{\sin }^2\mathrm{\&lambda;}+{\mathrm{<figure-callout\; id="33"\; label="g"\; filenames="HDA0000120732580000032.png"\; state="\{\{state\}\}">g</figure-callout>}}_{33}{\sin }^{22}\mathrm{\&phi;}+$

${2g}_{12}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000120732580000011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&phi;}\sin \mathrm{\&lambda;}\cos \mathrm{\&lambda;}+{2g}_{13}\sin \mathrm{\&phi;}\cos \mathrm{\&phi;}\cos \mathrm{\&lambda;}+{2g}_{23}\sin \mathrm{\&phi;}\cos \mathrm{\&phi;}\sin \mathrm{\&lambda;}$

$g_{44}^s=g_{44}$

Horizontal location dilution of precision based on the ENU coordinate system is:

The perpendicular positioning dilution of precision is: $\mathrm{VDOP}=\sqrt{g_{33}^s}.$

Step 180 is calculated the t horizontal location precision HACCU at net point place constantly _{Grid, t}=1.96HDOP*RMS _Grid, and the horizontal location service availability performance of grid points satellite navigation system ${\mathrm{Avail}}_{\mathrm{Hor},\mathrm{Grid}}=\frac{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}({\mathrm{HACCU}}_{\mathrm{Grid},t}<17)}{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}\left(H_{\mathrm{Grid},t}\right)}\&times;100\%.$

Wherein, Count (*) is a counting function.

Step 190 is calculated the t perpendicular positioning precision VACCU at net point place constantly _{Grid, t}=1.96VDOP*RMS _Grid, and the perpendicular positioning service availability performance of grid points satellite navigation system ${\mathrm{Avail}}_{\mathrm{Ver},\mathrm{Grid}}=\frac{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}({\mathrm{VACCU}}_{\mathrm{Grid},t}<37)}{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}\left({\mathrm{VACCU}}_{\mathrm{Grid},t}\right)}\&times;100\%.$

Following with reference to Fig. 2, introduce the concrete computation process of above-mentioned steps 120, as shown in the figure, comprise the steps:

Step 121 is calculated major semi-axis A, straight angle speed n ₀, be carved into when needing with reference to mistiming t constantly _k, correct straight angle speed n and mean anomaly M _k

Wherein,

GM=398600.5 (km ³/ s ²) be the terrestrial gravitation constant; t _k=t-t _Oe, constantly t must be the satellite-signal x time in GPST, it deducts propagation time delay by signal and obtain the time of reception, works as t _k=t-t _OeDuring greater than 302400 seconds, should be at t _kIn deduct corresponding second several 604800 a seconds GPS week, work as t _k=t-t _OeDuring less than-302400 seconds, should be at t _kIn add 604800 seconds; N=n ₀+ Δ n; M _k=M ₀+ n * t _k

Step 122 is according to equality M _k=E _k-e * sinE _kIterative computation eccentric anomaly E _k

Step 123 is calculated true anomaly v according to following system of equations _k, and calculate ascending node angular distance parameter phi _k=v _k+ ω,

$\left\{\begin{array}{c}\cos v_k=\frac{(\cos E_k-e)}{(1-e\&times;\cos E_k)}\\ \sin v_k=\frac{\sqrt{1-{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="HDA0000120732580000011.png"\; state="\{\{state\}\}">e</figure-callout>}}^2}\sin E_k}{(1-e\&times;\cos E_k)}\end{array}\right.$

Step 124 is according to following system of equations computation period correction member.

$\left\{\begin{array}{c}\mathrm{\&delta;}{u}_k=C_{\mathrm{us}}\sin \left(2{\mathrm{\&phi;}}_k\right)+C_{\mathrm{uc}}\cos \left(2{\mathrm{\&phi;}}_k\right)\\ \mathrm{\&delta;}{r}_k=C_{\mathrm{rs}}\sin \left(2{\mathrm{\&phi;}}_k\right)+C_{\mathrm{rc}}\cos \left(2{\mathrm{\&phi;}}_k\right)\\ \mathrm{\&delta;}{i}_k=C_{\mathrm{is}}\sin \left(2{\mathrm{\&phi;}}_k\right)+C_{\mathrm{ic}}\cos \left(2{\mathrm{\&phi;}}_k\right)\end{array}\right.$

Step 125 is calculated the ascending node angular distance parameters u after correcting _k=φ _k+ δ u _k, and after correcting to through r _k=A (1-e cos E _k)+δ r _k

Step 126 is calculated the coordinate x of satellite in orbit plane _k=r _kCos (u _k), y _k=r _kSin (u _k).

Step 127 is calculated the inclination angle i after correcting _k=i _o+ δ i _k+ (IDOT) _tK, and calculate right ascension of ascending node ${\mathrm{\&Omega;}}_k={\mathrm{\&Omega;}}_0+(\stackrel{\&CenterDot;}{\mathrm{\&Omega;}}-{\stackrel{\&CenterDot;}{\mathrm{\&Omega;}}}_e)t_k-{\stackrel{\&CenterDot;}{\mathrm{\&Omega;}}}_e{t}_{\mathrm{Oe}}.$

Wherein,

is the angular velocity (7.2921151467x1E-5rad/sec) of earth rotation.

Step 128 is calculated said satellite rough coordinates (X according to following system of equations _kY _kZ _k), and calculate said satellite summary clock correction $\mathrm{\&Delta;}{t}_{\mathrm{Sv}}=a_{f0}+a_{f1}(t-t_{\mathrm{Oc}})+a_{f2}{(t-t_{\mathrm{Oc}})}^2+\mathrm{Fe}\sqrt{A}\mathrm{Sin}{E}_k-T_{\mathrm{GD}},$

$\left\{\begin{array}{c}{X}_k=x_k\&times;\cos \left({\mathrm{\&Omega;}}_k\right)-y_k\&times;\cos \left(i_k\right)\&times;\sin \left({\mathrm{\&Omega;}}_k\right)\\ Y_k=x_k\&times;\sin \left({\mathrm{\&Omega;}}_k\right)+y_k\&times;\cos \left(i_k\right)\&times;\cos \left({\mathrm{\&Omega;}}_k\right)\\ Z_k=y_k\&times;\sin \left(i_k\right)\end{array}\right.$

Wherein, F is constant (4.442807633x1E-10sec/sqrt (meter)).

The said method of present embodiment is according to user's location requirement; The actual navigation data that provides according to satellite navigation system and the practical layout of satellite constellation; Propose the order of accuarcy of assessment navigation data and the feasible program of location service availability, gone for various satellite navigation system.

Fig. 3 is the structural representation of apparatus for evaluating embodiment of signal accuracy and the location service availability of satellite navigation system according to the invention; In order to realize said method; As shown in the figure; This device comprises: data download module 10, summary computing module 20, accurate computing module 30, error computing module 40, precision operations module 50, factor computing module 60, horizontal performance module 70 and Vertical performance module 80; Thick straight line among the figure representes that bus connects, and adopts other connected modes also can be fine.The principle of work of this device is following:

Data download module 10 is downloaded broadcast ephemeris file data and precise ephemeris file data from the website of IGS tissue; After the download; Can also be through 90 deletions of data deletion module by the unhealthy data in the said broadcast ephemeris file data of data download module 10 downloads, relevant unhealthy data can be referring to said method embodiment; Summary computing module 20 uses said broadcast ephemeris file to calculate satellite rough coordinates (X with reference to the description of GNSS interface document _kY _kZ _k) and satellite summary clock correction Δ t _Sv, the satellite ephemeris parameter in the said broadcast ephemeris file can be referring to table 1.

Accurate computing module 30 uses said precise ephemeris file to calculate satellite precise coordinate (X _p, Y _p, Z _p) and satellite precise clock correction Δ t _{Sv, p}Particularly, as shown in Figure 4, carry out Lagrange's interpolation through the satellite center-of-mass coordinate in 31 pairs of said precise ephemeris file datas of the interpolating unit in the accurate computing module 30 and calculate; To under the solid coordinate system of star, be converted into satellite phase center coordinate through the satellite center-of-mass coordinate after said Lagrange's interpolation is calculated by conversion unit 32 then as said satellite precise coordinate (X _p, Y _p, Z _p); And then carry out the satellite precise clock correction Δ t that Lagrange's interpolation is calculated any time according to said precise ephemeris file data by clock correction unit 33 _{Sv, p}Concrete interpolation formula can be referring to the related content of said method embodiment.

After this, calculate co-ordinates of satellite error (the Δ X=X of each minute by error computing module 40 _k-X _p, Δ Y=Y _k-Y _p, Δ Z=Z _k-Z _p) and satellite clock difference error delta t=Δ t _Sv-Δ t _{Sv, p}, and calculate t net point user ranging errors constantly ${\mathrm{URE}}_{\mathrm{Grid},t}=({\mathrm{\&Delta;}}_x^{\mathrm{Rs}}\&CenterDot;\mathrm{\&Delta;\; X}+{\mathrm{\&Delta;}}_y^{\mathrm{Rs}}\&CenterDot;\mathrm{\&Delta;\; Y}+{\mathrm{\&Delta;}}_z^{\mathrm{Rs}}\&CenterDot;\mathrm{\&Delta;\; Z})-\mathrm{C\&Delta;\; t};$ After this, by precision operations module 50 grid points user ranging errors precision

And to the whole world, the user ranging errors precision of statistics satellite navigation system

After this, calculate the t horizontal location dilution of precision of net point constantly by factor computing module 60

With the perpendicular positioning dilution of precision

Based on above-mentioned operation result, calculate the t horizontal location precision HACCU at net point place constantly by horizontal performance module 70 _{Grid, t}=1.96HDOP*RMS _Grid, and the horizontal location service availability performance of grid points satellite navigation system ${\mathrm{Avail}}_{\mathrm{Hor},\mathrm{Grid}}=\frac{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}({\mathrm{HACCU}}_{\mathrm{Grid},t}<17)}{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}\left(H_{\mathrm{Grid},t}\right)}\&times;100\%,$ And calculate the t perpendicular positioning precision VACCU at net point places constantly by Vertical performance module 80 _{Grid, t}=1.96VDOP*RMS _Grid, and the perpendicular positioning service availability performance of grid points satellite navigation system

${\mathrm{Avail}}_{\mathrm{ver},\mathrm{grid}}=\frac{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}({\mathrm{VACCU}}_{\mathrm{grid},t}<37)}{\underset{t}{\mathrm{\&Sigma;}}\mathrm{Count}\left({\mathrm{VACCU}}_{\mathrm{grid},t}\right)}\&times;100\%.$

The said device of present embodiment is according to user's location requirement; The actual navigation data that provides according to satellite navigation system and the practical layout of satellite constellation; Propose the order of accuarcy of assessment navigation data and the feasible program of location service availability, gone for various satellite navigation system.

One of ordinary skill in the art will appreciate that: all or part of step that realizes said method embodiment can be accomplished through the relevant hardware of programmed instruction; Aforesaid program can be stored in the computer read/write memory medium; This program the step that comprises said method embodiment when carrying out; And aforesaid storage medium comprises: various media that can be program code stored such as ROM, RAM, magnetic disc or CD.

What should explain at last is: above embodiment is only in order to explaining technical scheme of the present invention, but not to its restriction; Although with reference to previous embodiment the present invention has been carried out detailed explanation, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, and perhaps part technical characterictic wherein is equal to replacement; And these are revised or replacement, do not make the spirit and the scope of the essence disengaging various embodiments of the present invention technical scheme of relevant art scheme.

Claims (7)

1. the appraisal procedure of the signal accuracy of a satellite navigation system and location service availability is characterized in that, comprising:

Download the data of broadcast ephemeris file and the data of precise ephemeris file from the website of the international GPS IGS of service organization;

With reference to the description of global navigation satellite system GNSS interface document, use said broadcast ephemeris file to calculate satellite rough coordinates (X _kY _kZ _k) and satellite summary clock correction Δ t _Sv

Use said precise ephemeris file to calculate satellite precise coordinate (X _p, Y _p, Z _p) and satellite precise clock correction Δ t _{Sv, p}

Calculate co-ordinates of satellite error (the Δ X=X of each minute _k-X _p, Δ Y=Y _k-Y _p, Δ Z=Z _k-Z _p) and satellite clock difference error delta t=Δ t _Sv-Δ t _{Sv, p}

Calculate t net point user ranging errors

constantly

Grid points user ranging errors precision

also is directed against the whole world, the user ranging errors precision

of statistics satellite navigation system

Calculation grid points at time t horizontal positioning accuracy factor?

and vertical positioning accuracy factor

Calculate the t horizontal location precision HACCU at net point place constantly _{Grid, t}=1.96HDOP*RMS _Grid, and the horizontal location service availability performance of grid points satellite navigation system

Calculate the t perpendicular positioning precision VACCU at net point place constantly _{Grid, t}=1.96VDOP*RMS _Grid, and the perpendicular positioning service availability performance of grid points satellite navigation system

2. method according to claim 1 is characterized in that, also comprises after the said download broadcast ephemeris file data: delete the unhealthy data in the said broadcast ephemeris file data.

3. method according to claim 1 is characterized in that, said calculating satellite rough coordinates (X _kY _kZ _k) and satellite summary clock correction Δ t _SvComprise:

Calculate major semi-axis A, straight angle speed n ₀, be carved into when needing with reference to mistiming t constantly _k, correct straight angle speed n and mean anomaly M _k

According to equality M _k=E _k-e * sinE _kIterative computation eccentric anomaly E _k

According to system of equations

Calculate true anomaly v _k, and calculate ascending node angular distance parameter phi _k=v _k+ ω;

According to system of equations

computation period correction member;

Calculate the ascending node angular distance parameters u after correcting _k=φ _k+ δ u _k, and after correcting to through r _k=A (1-e cos E _k)+δ r _k

Calculate the coordinate x of satellite in orbit plane _k=r _kCos (u _k), y _k=r _kSin (u _k);

Calculate the inclination angle i after correcting _k=i _o+ δ i _k+ (IDOT) t _k, and calculate right ascension of ascending node

Roughly calculate the satellite coordinates

and calculate roughly the satellite clock error

4. method according to claim 1 is characterized in that, said calculating satellite precise coordinate and satellite precise clock correction comprise:

Satellite center-of-mass coordinate in the said precise ephemeris file is carried out Lagrange's interpolation to be calculated;

To under the solid coordinate system of star, be converted into satellite phase center coordinate through the satellite center-of-mass coordinate after said Lagrange's interpolation is calculated;

Carry out the satellite precise clock correction that Lagrange's interpolation is calculated any time according to the precise ephemeris file data.

5. the apparatus for evaluating of the signal accuracy of a satellite navigation system and location service availability is characterized in that, comprising:

Data download module is used for downloading the data of broadcast ephemeris file and the data of precise ephemeris file from the website of the international GPS IGS of service organization;

The summary computing module is used for the description with reference to the global navigation satellite system GNSS interface document, uses said broadcast ephemeris file to calculate satellite rough coordinates (X _kY _kZ _k) and satellite summary clock correction Δ t _Sv

Accurate computing module is used to use said precise ephemeris file to calculate satellite precise coordinate (X _p, Y _p, Z _p) and satellite precise clock correction Δ t _{Sv, p}

The error computing module is used to calculate co-ordinates of satellite error (the Δ X=X of each minute _k-X _p, Δ Y=Y _k-Y _p, Δ Z=Z _k-Z _p) and satellite clock difference error delta t=Δ t _Sv-Δ t _{Sv, p}, and calculate t net point user ranging errors constantly

The precision operations module; Be used for grid points user ranging errors precision

and, add up the user ranging errors precision

of satellite navigation system to the whole world

Factor computing module is used to calculate t the horizontal location dilution of precision

and the perpendicular positioning dilution of precision of net point constantly

Horizontal performance module is used to calculate the t horizontal location precision HACCU at net point place constantly _{Grid, t}=1.96HDOP*RMS _Grid, and the horizontal location service availability performance of grid points satellite navigation system

The Vertical performance module is used to calculate the t perpendicular positioning precision VACCU at net point place constantly _{Grid, t}=1.96VDOP*RMS _Grid, and the perpendicular positioning service availability performance of grid points satellite navigation system

6. device according to claim 5 is characterized in that, also comprises: data deletion module, the unhealthy data that are used for deleting the said broadcast ephemeris file data of being downloaded by data download module.

7. device according to claim 5 is characterized in that, said accurate computing module comprises:

Interpolating unit is used for that the satellite center-of-mass coordinate of said precise ephemeris file data is carried out Lagrange's interpolation and calculates;

Conversion unit is used for the satellite center-of-mass coordinate after calculating through said Lagrange's interpolation is converted into satellite phase center coordinate as said satellite precise coordinate under the solid coordinate system of star;

The clock correction unit is used for carrying out the satellite precise clock correction that Lagrange's interpolation is calculated any time according to said precise ephemeris file data.

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