CN102565814B - 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 appraisal procedure that the present invention relates to a kind of signal accuracy and location service availability of satellite navigation system, belongs to Satellite Navigation Technique field.

Background technology

Along with the progressively development of satellite navigation system technology, following GPS (the Global Positioning System that not only has the U.S., 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.For user location, the satellite navigation signals performance that space constellation systems provides has determined user's basic navigation positioning performance together with communication environments error and receiver user performance.Wherein, satellite navigation signals precision is the unique part that can control and ensure of satellite navigation system ISP.User is located to availability, and different service availabilities has determined whether satellite navigation can be used for specific application, and is the basis that exploitation respective satellite strengthens system.In order to assess signal accuracy and the service availability of different satellite navigation systems, be necessary to develop a kind of unified appraisal procedure.

Summary of the invention

The invention provides a kind of appraisal procedure of signal accuracy and location service availability of satellite navigation system, to realize the unified assessment for 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 described broadcast ephemeris file to calculate satellite rough coordinates (X _ky _kz _k) and satellite summary clock correction Δ t _sv;

Use described 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 the poor error delta t=Δ of satellite clock t _sv-Δ t _{sv, p};

Calculate t moment net point user ranging errors ${\mathrm{URE}}_{\mathrm{grid},t}=({\mathrm{\Δ}}_x^{\mathrm{rs}}\·\mathrm{\ΔX}+{\mathrm{\Δ}}_y^{\mathrm{rs}}\·\mathrm{\ΔY}+{\mathrm{\Δ}}_z^{\mathrm{rs}}\·\mathrm{\ΔZ})-\mathrm{c\Δt};$

Computing grid point user ranging errors precision and for the whole world, the user ranging errors precision of statistics satellite navigation system

Calculate the horizontal location dilution of precision of t moment net point with perpendicular positioning dilution of precision $\mathrm{VDOP}=\sqrt{g_{33}^s};$

Calculate the horizontal location precision HACCU at t moment net point place _{grid, t}=1.96HDOP*RMS _grid, and the horizontal location service availability performance of computing grid point 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 perpendicular positioning precision VACCU at t moment net point place _{grid, t}=1.96VDOP*RMS _grid, and the perpendicular positioning service availability performance of computing grid point 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, for downloading broadcast ephemeris file data and precise ephemeris file data from the website of IGS tissue;

Summary computing module, for the description with reference to GNSS interface document, uses described broadcast ephemeris file to calculate satellite rough coordinates (X _ky _kz _k) and satellite summary clock correction Δ t _sv;

Accurate computing module, for using described precise ephemeris file to calculate satellite precise coordinate (X _p, Y _p, Z _p) and satellite precise clock correction Δ t _{sv, p};

Error computing module, for calculating 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 the poor error delta t=Δ of satellite clock t _sv-Δ t _{sv, p}, and calculate t moment net point user ranging errors ${\mathrm{URE}}_{\mathrm{grid},t}=({\mathrm{\&Delta;}}_x^{\mathrm{rs}}\&CenterDot;\mathrm{\&Delta;X}+{\mathrm{\&Delta;}}_y^{\mathrm{rs}}\&CenterDot;\mathrm{\&Delta;Y}+{\mathrm{\&Delta;}}_z^{\mathrm{rs}}\&CenterDot;\mathrm{\&Delta;Z})-\mathrm{c\&Delta;t};$

Precision operations module, for computing grid point user ranging errors precision and for the whole world, the user ranging errors precision of statistics satellite navigation system

Factor computing module, for calculating the horizontal location dilution of precision of t moment net point with perpendicular positioning dilution of precision

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

Vertical performance module, for calculating the perpendicular positioning precision VACCU at t moment net point place _{grid, t}=1.96VDOP*RMS _grid, and the perpendicular positioning service availability performance of computing grid point 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 providing according to satellite navigation system and the practical layout of satellite constellation, propose the assessment order of accuarcy of navigation data and the feasible program of location service availability, gone for various satellite navigation system.

Brief description of the drawings

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

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

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

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

Embodiment

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

Step 110, downloads broadcast ephemeris file data and precise ephemeris file data from the website of IGS tissue.

Wherein, described IGS tissue refers to international GPS service tissue, is the office of international organization that instructs various countries' Satellite Navigation Technique development; Particularly, (File Transfer Protocol is called for short: FTP) realize and downloading can to pass through file transfer protocol (FTP).

After download, can also delete the unhealthy data in described 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 0 data, the data that satellite URA (User Range Accuracy is called for short: distance accuracy index) is more than or equal to 48 meters etc.

Step 120, with reference to the description of GNSS interface document, is used described broadcast ephemeris file to calculate satellite rough coordinates (X _ky _kz _k) and satellite summary clock correction Δ t _sv;

Wherein, described GNSS interface refers to GLONASS (Global Navigation Satellite System) (Global Navigation Satellite System) interface; Satellite ephemeris parameter shown in described broadcast ephemeris file including table 1:

Table 1

Step 130, is used described precise ephemeris file to calculate satellite precise coordinate (X _p, Y _p, Z _p) and satellite precise clock correction Δ t _{sv, p}.

Particularly, SP3 (Standard Product 3 Orbit Format are called for short: standard trajectory product format) the precise ephemeris file that announce the website of IGS tissue for example, has provided satellite precise coordinate and the satellite precise clock correction in corresponding GPS moment according to certain hour interval (15 minutes).Performance evaluation system can customize the time interval (for example 1 minute) and calculates the user ranging errors in corresponding moment.If the time interval that performance evaluation system Self defined time interval and SP3 precise ephemeris file are given is inconsistent, can pass through Lagrange's interpolation, calculated satellite precise coordinate and the satellite precise clock correction in the moment of selecting by precise ephemeris file.General in order to reduce the interpolation error on time boundary, can select the precise ephemeris file of three days to calculate the High Precision Satellite Ephemeris of central a day.The exponent number of Lagrange's interpolation can be self-defined.Taking seven rank Lagrange's interpolations as example, 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 precise ephemeris file provides is centroid of satellite coordinate, and the co-ordinates of satellite that broadcast ephemeris provides is Satellite Phase centre coordinate.The phase center deviation data that uses IGS regularly to announce, the centroid of satellite coordinate that Lagrange's interpolation is calculated is converted into Satellite Phase centre coordinate under the solid coordinate system of star, and this Satellite Phase centre 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 precise ephemeris file data _{sv, p}.

Step 140, calculates 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 the poor error delta t=Δ of satellite clock t _sv-Δ t _{sv, p}.

Step 150, calculates t moment net point user ranging errors.

Particularly, be the grid of 5 degree x5 degree by global subdivision, according to the coordinate of each net point, calculate the error projection of co-ordinates of satellite error to respective grid points.To each net point, in computation process, only consider the satellite of the elevation angle more than 5 degree.According to 1 minutes interval, the user ranging errors in each each moment of grid is calculated, continued 24 hours.

Hypothetical trellis point coordinate is X _u, Y _u, Z _u, computing grid is put to the coordinate vector of satellite and is:

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

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

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

The user ranging errors when moment t of this net point place is:

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

Step 160, computing grid point user ranging errors precision, and for the whole world, the user ranging errors precision of statistics satellite navigation system.

Particularly, first to delete the exceptional value that does not meet gps signal specification.Delete the sample that URE is greater than a certain thresholding, thresholding, according to gps signal normative choice, is taken as 25 meters.Then for each net point, user ranging errors sample in all satellites of observing according to net point 24 hours, the user ranging errors precision of statistics net point is for the whole world, the user ranging errors precision of statistics satellite navigation system is:

Step 170, the horizontal location dilution of precision of calculating t moment net point with perpendicular positioning dilution of precision

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

$H=\left[\begin{array}{cccc}{l}_1& m_1& n_1& 1\\ l_2& m_2& n_2& 1\\ .& .& .& .\\ .& .& .& .\\ .& .& .& .\\ l_n& m_n& n_n& 1\end{array}\right]$

Wherein, l _j, m _jand n _jrepresent to be pointed to by apparent position the direction cosine of the unit vector of j satellite; Then calculate G=(H ^th) ^-1, and suppose that the representation in components of G is,

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

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

$g_{11}^s=g_{11}{\sin }^2\mathrm{\&phi;}{\cos }^2\mathrm{\&lambda;}+g_{22}{\sin }^2\mathrm{\&phi;}{\sin }^2\mathrm{\&lambda;}+g_{33}{\cos }^2\mathrm{\&phi;}+$

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

$g_{22}^s=g_{11}{\sin }^2\mathrm{\&lambda;}-2g_{12}\sin \mathrm{\&lambda;}\cos \mathrm{\&lambda;}+g_{22}{\cos }^2\mathrm{\&lambda;}$

$g_{33}^s=g_{11}{\cos }^2\mathrm{\&phi;}{\cos }^2\mathrm{\&lambda;}+g_{22}{\cos }^2\mathrm{\&phi;}{\sin }^2\mathrm{\&lambda;}+g_{33}{\sin }^{22}\mathrm{\&phi;}+$

${2g}_{12}{\cos }^2\mathrm{\&phi;}\sin \mathrm{\&lambda;}\cos \mathrm{\&lambda;}+{2g}_{13}\sin \mathrm{\&phi;}\cos \mathrm{\&phi;}\cos \mathrm{\&lambda;}+{2g}_{23}\sin \mathrm{\&phi;}\cos \mathrm{\&phi;}\sin \mathrm{\&lambda;}$

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

Horizontal location dilution of precision based on ENU coordinate system is: perpendicular positioning dilution of precision is: $\mathrm{VDOP}=\sqrt{g_{33}^s}.$

Step 180, the horizontal location precision HACCU at calculating t moment net point place _{grid, t}=1.96HDOP*RMS _grid, and the horizontal location service availability performance of computing grid point 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 counting function.

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

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

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

Wherein, gM=398600.5 (km ³/ s ²) be Gravitational coefficient of the Earth; t _k=t-t _oe, moment 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 _oewhile being greater than 302400 seconds, should be at t _kin deduct one GPS week corresponding number of seconds 604800 seconds, work as t _k=t-t _oewhile being 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, according to equation M _k=E _k-e × sinE _kiterative computation eccentric anomaly E _k.

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

$\left\{\begin{array}{c}\cos v_k=\frac{(\cos E_k-e)}{(1-e\&times;\cos E_k)}\\ \sin v_k=\frac{\sqrt{1-e^2}\sin E_k}{(1-e\&times;\cos E_k)}\end{array}\right.$

Step 124, 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, calculates 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, calculates the coordinate x of satellite in orbit plane _k=r _kcos (u _k), y _k=r _ksin (u _k).

Step 127, calculates 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, the angular velocity (7.2921151467x1E-5rad/sec) of earth rotation.

Step 128, calculates described satellite rough coordinates (X according to following system of equations _ky _kz _k), and calculate described satellite summary clock correction $\mathrm{\&Delta;}{t}_{\mathrm{sv}}=a_{f0}+a_{f1}(t-t_{\mathrm{oc}})+a_{f2}{(t-t_{\mathrm{oc}})}^2+\mathrm{Fe}\sqrt{A}\sin E_k-T_{\mathrm{GD}},$

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

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

Described in the present embodiment, method is according to user's location requirement, the actual navigation data providing according to satellite navigation system and the practical layout of satellite constellation, propose the assessment order of accuarcy of navigation data and the feasible program of location service availability, gone for various satellite navigation system.

Fig. 3 is the structural representation of the signal accuracy of satellite navigation system of the present invention and the apparatus for evaluating embodiment of location service availability, 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 in figure represents that bus connects, and adopts other connected modes also can be fine.The principle of work of this device is as follows:

Data download module 10 is downloaded broadcast ephemeris file data and precise ephemeris file data from the website of IGS tissue, after download, can also delete the unhealthy data in the described broadcast ephemeris file data of being downloaded by data download module 10 by data removing module 90, relevant unhealthy data can be referring to said method embodiment; Summary computing module 20, with reference to the description of GNSS interface document, uses described broadcast ephemeris file to calculate satellite rough coordinates (X _ky _kz _k) and satellite summary clock correction Δ t _sv, the satellite ephemeris parameter in described broadcast ephemeris file can be referring to table 1.

Accurate computing module 30 uses described 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, by the interpolating unit 31 in accurate computing module 30, the centroid of satellite coordinate in described precise ephemeris file data is carried out to Lagrange's interpolation calculating; Then by conversion unit 32, the centroid of satellite coordinate after described Lagrange's interpolation is calculated is converted into Satellite Phase centre coordinate as described satellite precise coordinate (X under the solid coordinate system of star _p, Y _p, Z _p); And then carry out Lagrange's interpolation by clock correction unit 33 according to described precise ephemeris file data and calculate the satellite precise clock correction Δ t of any time _{sv, p}.Concrete interpolation formula can be referring to the related content of said method embodiment.

After this, calculated 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 the poor error delta t=Δ of satellite clock t _sv-Δ t _{sv, p}, and calculate t moment net point user ranging errors ${\mathrm{URE}}_{\mathrm{grid},t}=({\mathrm{\&Delta;}}_x^{\mathrm{rs}}\&CenterDot;\mathrm{\&Delta;X}+{\mathrm{\&Delta;}}_y^{\mathrm{rs}}\&CenterDot;\mathrm{\&Delta;Y}+{\mathrm{\&Delta;}}_z^{\mathrm{rs}}\&CenterDot;\mathrm{\&Delta;Z})-\mathrm{c\&Delta;t};$ After this, by precision operations module 50 computing grid point user ranging errors precision and for the whole world, the user ranging errors precision of statistics satellite navigation system after this, calculated the horizontal location dilution of precision of t moment net point by factor computing module 60 with perpendicular positioning dilution of precision

Based on above-mentioned operation result, calculated the horizontal location precision HACCU at t moment net point place by horizontal performance module 70 _{grid, t}=1.96HDOP*RMS _grid, and the horizontal location service availability performance of computing grid point 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 calculated the perpendicular positioning precision VACCU at t moment net point place by Vertical performance module 80 _{grid, t}=1.96VDOP*RMS _grid, and the perpendicular positioning service availability performance of computing grid point satellite navigation system

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

Described in the present embodiment, device is according to user's location requirement, the actual navigation data providing according to satellite navigation system and the practical layout of satellite constellation, propose the assessment order of accuarcy of 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 complete by the relevant hardware of programmed instruction, aforesaid program can be stored in a computer read/write memory medium, this program, in the time carrying out, is carried out the step that comprises said method embodiment; And aforesaid storage medium comprises: various media that can be program code stored such as ROM, RAM, magnetic disc or CDs.

Finally it should be noted that: above embodiment only, in order to technical scheme of the present invention to be described, is not intended to limit; Although the present invention is had been described in detail with reference to previous embodiment, those of ordinary skill in the art is to be understood that: its technical scheme that still can record aforementioned each embodiment is modified, or part technical characterictic is wherein equal to replacement; And these amendments or replacement do not make the essence of appropriate technical solution depart from the spirit and scope of various embodiments of the present invention technical scheme.

Claims (7)

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

Organize the website of IGS to download the data of broadcast ephemeris file and the data of precise ephemeris file from international GPS service;

With reference to the description of global navigation satellite system GNSS interface document, use described broadcast ephemeris file to calculate satellite rough coordinates (X _ky _kz _k) and satellite summary clock correction Δ t _sv;

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

Calculate the co-ordinates of satellite error delta X=X of each minute _k-X _p, Δ Y=Y _k-Y _p, Δ Z=Z _k-Z _pwith the poor error delta t=Δ of satellite clock t _sv-Δ t _{sv, p};

Calculate t moment net point user ranging errors described net point is to be the net point that 5 degree x5 degree obtain by global subdivision, wherein, and parameter for net point is to the coordinate vector of satellite;

Computing grid point user ranging errors precision and for the whole world, the user ranging errors precision of statistics satellite navigation system

Calculate the horizontal location dilution of precision of t moment net point with perpendicular positioning dilution of precision wherein, symbol for the G matrix conversion based on ECEF coordinate system is to the value of each component on principal diagonal after local ENU coordinate system; The representation in components of the G matrix based on ECEF coordinate system is

Wherein, G=(H ^th) ^-1, H is the observing matrix that net point arrives all satellites in view;

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

Calculate the perpendicular positioning precision VACCU at t moment net point place _{grid, t}=1.96VDOP*RMS _grid, and the perpendicular positioning service availability performance of computing grid point satellite navigation system wherein, Count (*) is counting function.

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

3. method according to claim 1, is characterized in that, described calculating satellite rough coordinates (X _ky _kz _k) and satellite summary clock correction △ t _svcomprise:

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

According to equation M _k=E _k-e × sinE _kiterative computation eccentric anomaly E _k;

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

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-ecosE _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

and calculate described satellite summary clock correction e is flat heart rate, and ω is the argument of perigee, C _usfor at ephemeris with reference to moment t _oeprolong the amplitude of cycle correction sine term in mark direction at track, C _rsfor at ephemeris with reference to moment t _oeat the track amplitude of cycle correction sine term in the radial direction, C _isfor at ephemeris with reference to moment t _oethe orbit inclination cycle is corrected the amplitude of sine term, C _ucfor at ephemeris with reference to moment t _oeprolong the amplitude of cycle correction cosine term in mark direction at track, C _rcfor at ephemeris with reference to moment t _oeat the track amplitude of cycle correction cosine term in the radial direction, C _icfor at ephemeris with reference to moment t _oethe orbit inclination cycle is corrected the amplitude of cosine term, i ₀for with reference to moment orbit inclination, for the right ascension of ascending node secular variation in plane under the line, Ω ₀for with reference to moment right ascension of ascending node, t _oefor ephemeris is with reference to the moment, a _f0for satellite clock correction constant term, a _f1for satellite clock correction drift term, a _f2for satellite clock correction drift speed item, IDOT is orbit inclination rate of change, δ u _k, δ r _k, δ i _kfor cycle correction member, for the angular velocity of earth rotation, t _ocfor satellite clock is with reference to the moment, T _gDfor delay inequality corrects, F is constant.

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

Centroid of satellite coordinate in described precise ephemeris file is carried out to Lagrange's interpolation calculating;

Centroid of satellite coordinate after described Lagrange's interpolation is calculated is converted into Satellite Phase centre coordinate under the solid coordinate system of star;

Carry out Lagrange's interpolation according to precise ephemeris file data and calculate the satellite precise clock correction of any time.

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

Data download module, downloads the data of broadcast ephemeris file and the data of precise ephemeris file for the website of organizing IGS from international GPS service;

Summary computing module, for the description with reference to global navigation satellite system GNSS interface document, uses described broadcast ephemeris file to calculate satellite rough coordinates (X _ky _kz _k) and satellite summary clock correction △ t _sv;

Accurate computing module, for using described precise ephemeris file to calculate satellite precise coordinate (X _p, Y _p, Z _p) and satellite precise clock correction Δ t _{sv, p};

Error computing module, for calculating the co-ordinates of satellite error delta X=X of each minute _k-X _p, Δ Y=Y _k-Y _p, Δ Z=Z _k-Z _pwith the poor error delta t=Δ of satellite clock t _sv-Δ t _{sv, p}, and calculate t moment net point user ranging errors described net point is to be the net point that 5 degree x5 degree obtain by global subdivision, wherein, and parameter for net point is to the coordinate vector of satellite;

Precision operations module, for computing grid point user ranging errors precision and for the whole world, the user ranging errors precision of statistics satellite navigation system

Factor computing module, for calculating the horizontal location dilution of precision of t moment net point with perpendicular positioning dilution of precision wherein, symbol for the G matrix conversion based on ECEF coordinate system is to the value of each component on principal diagonal after local ENU coordinate system; The representation in components of the G matrix based on ECEF coordinate system is

Wherein, G=(H ^th) ^-1, H is the observing matrix that net point arrives all satellites in view;

Horizontal performance module, for calculating the horizontal location precision HACCU at t moment net point place _{grid, t}=1.96HDOP*RMS _grid, and the horizontal location service availability performance of computing grid point satellite navigation system

Vertical performance module, for calculating the perpendicular positioning precision VACCU at t moment net point place _{grid, t}=1.96VDOP*RMS _grid, and the perpendicular positioning service availability performance of computing grid point satellite navigation system wherein, Count (*) is counting function.

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

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

Interpolating unit, carries out Lagrange's interpolation calculating for the centroid of satellite coordinate to described precise ephemeris file data;

Conversion unit, for being converted into Satellite Phase centre coordinate as described satellite precise coordinate using the centroid of satellite coordinate after described Lagrange's interpolation is calculated under the solid coordinate system of star;

Clock correction unit, calculates the satellite precise clock correction of any time for carry out Lagrange's interpolation according to described precise ephemeris file data.