CN103954982A - Rapid visible satellite selection method based on multimode GNSS receiver - Google Patents

Abstract

The invention discloses a rapid visible satellite selection method based on a multimode GNSS receiver. The method comprises the steps that (1) elevation angles, received by the multimode GNSS receiver currently, of all visible satellites are calculated, the satellites with the satellite elevation angles smaller than 10 degrees are eliminated, and a usable visible satellite set S is obtained; (2) according to satellite position information of the satellites and receiver preliminary position information, a coefficient matrix and a weight coefficient matrix are calculated; (3) a GDOP value corresponding to the visible satellite set S is calculated; (4) a contribution value delta Gi of each visible satellite to GDOP is calculated and the contribution values delta Gi are ranked from large to small, so that a set SG is formed; (5) when the multimode GNSS receiver needs to select N visible satellites for navigation and location, the front N satellites in the set SG are selected, and a corresponding visible satellite subset is a selected usable satellite constellation. The method has the advantages of being convenient and quick to operate, simple in implementation, high in accuracy, wide in application range and the like.

Description

Visible satellite fast selecting method based on multimode GNSS receiver

Technical field

The present invention is mainly concerned with satellite navigation field, refers in particular to a kind of visible satellite fast selecting method based on multimode GNSS receiver.

Background technology

Along with GPS (Global Position System) GNSS(Global Navigation Satellite System) industry flourish, various countries are for GNSS pay attention to day by day.GNSS mainly comprises Galileo and the Chinese Beidou satellite navigation system BDS(BeiDou Navigation Satellite System that GPS, GLONASS, European Union are building at present, also referred to as Compass).The development of GNSS industry embody a concentrated reflection of comprise aeroamphibious sky all trades and professions all wide-scale adoption GNSS receiver carry out navigator fix application.

The U.S. is implementing GPS updating program; Russia is carrying out technical renovation and increase satellite in orbit for the navigator fix ability of recovering and improves GLONASS; The Beidou satellite navigation system of China has started to provide navigator fix service for the Asian-Pacific area; European Union is just moving forward steadily the construction of Galileo.Theory and practice shows, adopts the performance of multimode GNSS co-located at aspects such as precision, reliability, integrity, to be all better than the performance that adopts single GNSS system to locate.From early stage GPS/GLONASS dual mode receiver to present BDS/GPS/GLONASS tri-mould receivers, to the BD/GPS/GLONASS/Galileo tetra-mould receivers in not far future, multimode GNSS co-located is the development and application trend of Modern Satellite receiver.For single GNSS location, because usable satellite number in multimode GNSS location is many and each GNSS system system, the not impact of equal factor of Constellation Design, the system of selection of usable satellite (referred to as satellite selection method) seems particularly important.Therefore, selecting star to become one of gordian technique of multimode GNSS receiver co-located, is the bonding agent of realizing the common location of different GNSS systems.

Along with the operable Navsat number of active user is more and more, the star algorithm of selecting of selecting star technology more and more to receive the concern, particularly BD/GPS co-located of Chinese scholars of multimode GNSS becomes study hotspot and emphasis.Early stage GPS receiver, owing to being subject to the restriction of hardware resource, only have 4～6 signal receiving cables, and GPS generally can normally receive 8～10 satellite-signals in open environment; Therefore, in this technology, there is the problem of selecting star.

Along with the performance of microprocessor and large scale integrated circuit is constantly improved, the GPS receiver that comprises dozens or even hundreds of signal trace passage becomes a reality, receiving all visible satellite signals carries out navigator fix and has not become problem, therefore for single GNSS, select the demand of star technology not urgent, but more for the satellite selection method research of GPS/GLONASS bimodulus location.Chinese scholars is mainly to derive and carry out GPS/GLONASS and select star algorithm research based on the optimum theory of geometric dilution of precision (Geometric Dilution of Precision, GDOP).Because receiver is different with the observational error of GLONASS satellite to GPS, generally adopt the improvement of weighted GDOP to select star algorithm.Elevation of satellite has determined observational error size to a great extent, thereby many researchers select in improvement on the basis of star algorithm and considered elevation of satellite to selecting the impact of star.Weights for weighted GDOP are determined, mainly based on two kinds of thinkings: the one, comprehensive utilization experimental formula and error model are predicted the weights of estimating to obtain every satellite for observational error; The 2nd, by introducing, comprise that the probabilistic model of system difference determines the weights of every/every class satellite.

Up to now, the system of selection of multimode GNSS receiver visible satellite is mainly to adopt empirical method or approximation method design satellite selection method, there is no strict mathematical theory derivation reference, have the deficiencies such as precision is not high, calculation of complex, be difficult to be applicable to completely the demand of multimode GNSS receiver location.

Summary of the invention

The technical problem to be solved in the present invention is just: the technical matters existing for prior art, the invention provides a kind of easy and simple to handle fast, realize simple, the precision visible satellite fast selecting method based on multimode GNSS receiver high, applied widely.

For solving the problems of the technologies described above, the present invention by the following technical solutions:

A usable satellite fast selecting method based on multimode GNSS receiver, the steps include:

(1) calculate the elevation angle that current multimode GNSS receiver receives all visible satellites, reject the satellite that satellite elevation angle is less than 10 degree, obtain available visible satellite S set;

(2) the visible satellite S set obtaining for above-mentioned steps (1), according to the satellite position of satellite and receiver general location information, design factor matrix and weight coefficient matrix;

(3) calculate GDOP value corresponding to visible satellite S set;

(4) calculate the contribution margin △ G of every visible satellite to GDOP _i, and according to contribution margin △ G _iarrange from big to small and form S set _g;

(5) when multimode GNSS receiver need to select N visible satellite to carry out navigator fix, N is greater than 1, selects S set _gin N satellite above, be N visible satellite combination of GDOP minimum, corresponding visible satellite subset is the usable satellite constellation of selection.

As a further improvement on the present invention: the visible satellite S set obtaining in described step (1) is:

S={s _i|elv _si>10 ⁰,1≤i≤M}

Wherein, s _ibe i visible satellite, elv _sifor s _isatellite is with respect to the elevation angle of receiver, and M is visible satellite number;

The idiographic flow of described step (2) is:

(2.1) visible satellite position and receiver general location are the vector of ECEF coordinate system, and the position of j visible satellite is X ^j=[x ^jy ^jz ^j] and receiver general location be X ₀=[x ₀y ₀z ₀], coefficient matrices A computing formula is:

Wherein, for the direction cosine of receiver to satellite j observation vector, specific formula for calculation be:

$e_x^j=\frac{x_0-x^j}{\sqrt{{(x_0-x^j)}^2+{(y_0-y^j)}^2+{(z_0-z^j)}^2}}$

$e_y^j=\frac{y_0-y^j}{\sqrt{{(x_0-x^j)}^2+{(y_0-y^j)}^2+{(z_0-z^j)}^2}}$

$e_z^j=\frac{z_0-z^j}{\sqrt{{(x_0-x^j)}^2+{(y_0-y^j)}^2+{(z_0-z^j)}^2}}$

(2.2) weight coefficient matrix Q is:

Q=(A ^TA)- ¹。

As a further improvement on the present invention: in described step (3), the formula that calculates GDOP value according to weight coefficient matrix Q is:

$\mathrm{GDOP}=\sqrt{\mathrm{trace}\left(Q\right)}=\sqrt{\mathrm{trace}\left({\left(A^{T}A\right)}^{-1}\right)}$

Wherein, the mark of trace (Q) representing matrix Q, is matrix Q diagonal entry sum.

As a further improvement on the present invention: the idiographic flow of described step (4) is:

(4.1) calculate the contribution margin △ G of every visible satellite to GDOP _i:

${\mathrm{\ΔG}}_i={\mathrm{GDOP}}_{M-1}^i-{\mathrm{GDOP}}_M$

Wherein, GDOP _mfor adopting M the GDOP value that visible satellite observed reading calculates, for adopting M-1 and do not comprise the GDOP value that i visible satellite calculates;

(4.2) the △ G to M satellite _ivalue, arranges and forms S set according to order from big to small _g:

S _G={s _i|△G _i≥△G _i-1,1≤i≤M}。

As a further improvement on the present invention: in described step (5), selected visible satellite set is

S _N={s _i|△G _i≥△G _i-1,(M-N+1)≤i≤M}

S _nbe N visible satellite combination of GDOP minimum, corresponding visible satellite subset is the usable satellite constellation of selection.

Compared with prior art, the invention has the advantages that:

1, the usable satellite fast selecting method based on multimode GNSS receiver of the present invention, has advantages of that calculating is simple, precision is high and application is wide, can be widely used in improving aeroamphibious sky by the positioning precision of multimode GNSS navigation neceiver and select star speed.

2, the usable satellite fast selecting method based on multimode GNSS receiver of the present invention, every the satellite of take is criterion to the contribution margin size of GDOP, be applicable to the multimode GNSS receivers such as GPS/BDS, the method is equally applicable to the selection of single system GNSS receiver visible satellite, thereby has expanded the suitable application area of the method.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of the inventive method.

Embodiment

Below with reference to Figure of description and specific embodiment, the present invention is described in further details.

As shown in Figure 1, the visible satellite fast selecting method based on multimode GNSS receiver of the present invention, for: first, by rejecting the elevation angle, be less than the visible satellite of 10 degree, obtain available visible satellite set; Then, for visible satellite set obtained above, according to the satellite position of satellite and receiver general location information, design factor matrix and weight coefficient matrix, thus calculate GDOP value; Then, calculate the contribution margin of every visible satellite to GDOP value, and arrange from big to small formation according to contribution margin; Finally, select some the satellites large to GDOP value contribution margin, be the visible satellite combination of GDOP minimum, corresponding visible satellite subset is the usable satellite constellation of selection.

In concrete application example, idiographic flow of the present invention is:

1. the elevation angle of all visible satellites that calculating multimode GNSS receiver receives, rejects the satellite that satellite elevation angle is less than 10 degree, obtains available visible satellite S set and is:

S={s _i| elv _si>=10 ⁰, 1≤i≤M} (1) wherein, s _ibe i visible satellite, elv _sifor s _isatellite is with respect to the elevation angle of receiver, and M is visible satellite number.For BDS/GPS dual mode receiver, the M that current M is not more than 26, BDS/GPS/GLONASS, tri-mould receivers is not more than 40, and the M of following BDS/GPS/GLONASS/Galileo tetra-mould receivers is not more than 52.

2. the visible satellite S set that pair above-mentioned steps 1 obtains, according to the satellite position of satellite and receiver general location information, design factor matrix and weight coefficient matrix.Concrete steps are as follows:

2.1, visible satellite position and receiver general location are the vector of ECEF coordinate system, and the position of j visible satellite is X ^j=[x ^jy ^jz ^j] and receiver general location be X ₀=[x ₀y ₀z ₀], coefficient matrices A computing formula is:

Wherein, for the direction cosine of receiver to satellite j observation vector, specific formula for calculation be:

$e_x^j=\frac{x_0-x^j}{\sqrt{{(x_0-x^j)}^2+{(y_0-y^j)}^2+{(z_0-z^j)}^2}}---\left(3\right)$

$e_y^j=\frac{y_0-y^j}{\sqrt{{(x_0-x^j)}^2+{(y_0-y^j)}^2+{(z_0-z^j)}^2}}---\left(4\right)$

$e_z^j=\frac{z_0-z^j}{\sqrt{{(x_0-x^j)}^2+{(y_0-y^j)}^2+{(z_0-z^j)}^2}}---\left(5\right)$

2.2, weight coefficient matrix Q is:

Q=(A ^TA)- ¹（ ⁶）

3. the weight coefficient matrix Q obtaining according to above-mentioned steps 2, the formula that calculates GDOP value is:

$\mathrm{GDOP}=\sqrt{\mathrm{trace}\left(Q\right)}=\sqrt{\mathrm{trace}\left({\left(A^{T}A\right)}^{-1}\right)}---\left(7\right)$

Wherein, the mark of trace (Q) representing matrix Q, is matrix Q diagonal entry sum.

4. calculate the contribution margin △ G of every visible satellite to GDOP _i, and according to △ G _iarrange from big to small and form S set G.Concrete steps are as follows:

4.1, calculate the contribution margin △ G of every visible satellite to GDOP _i

${\mathrm{\ΔG}}_i={\mathrm{GDOP}}_{M-1}^i-{\mathrm{GDOP}}_M---\left(8\right)$

Wherein, GDOP _mfor adopting M the GDOP value that visible satellite observed reading calculates, for adopting (M-1) and not comprising the GDOP value that i visible satellite calculates.

According to the monotonicity of calculating GDOP, must △ G _i>0, and △ G _ilarger, show that i satellite is to GDOP _mcontribution larger, thereby by △ G _ivalue as the measurement index of i satellite contribution importance.

4.2, the △ G to M satellite _ivalue, arranges and forms S set according to order from big to small _g

S _G={s _i|△G _i≥△G _i-1,1≤i≤M} （9）

5. need to select N(N≤M) visible satellite carries out navigator fix, selects visible satellite S set _gin N satellite above, i.e. selected visible satellite set is

S _N={s _i|△G _i≥△G _i-1,(M-N+1)≤i≤M} （10）

S _nbe N visible satellite combination of GDOP minimum, corresponding visible satellite subset is the usable satellite constellation of selection.

Below be only the preferred embodiment of the present invention, protection scope of the present invention is also not only confined to above-described embodiment, and all technical schemes belonging under thinking of the present invention all belong to protection scope of the present invention.It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principles of the present invention, should be considered as protection scope of the present invention.

Claims (5)

1. the usable satellite fast selecting method based on multimode GNSS receiver, is characterized in that, step is:

(1) calculate the elevation angle that current multimode GNSS receiver receives all visible satellites, reject the satellite that satellite elevation angle is less than 10 degree, obtain available visible satellite S set;

(2) the visible satellite S set obtaining for above-mentioned steps (1), according to the satellite position of satellite and receiver general location information, design factor matrix and weight coefficient matrix;

(3) calculate GDOP value corresponding to visible satellite S set;

(4) calculate the contribution margin △ G of every visible satellite to GDOP _i, and according to contribution margin △ G _iarrange from big to small and form S set _g;

(5) when multimode GNSS receiver need to select N visible satellite to carry out navigator fix, N is greater than 1, selects S set _gin N satellite above, be N visible satellite combination of GDOP minimum, corresponding visible satellite subset is the usable satellite constellation of selection.

2. the usable satellite fast selecting method based on multimode GNSS receiver according to claim 1, is characterized in that, the visible satellite S set obtaining in described step (1) is:

S={s _i|elv _si>10 ⁰,1≤i≤M}

Wherein, s _ibe i visible satellite, elv _sifor s _isatellite is with respect to the elevation angle of receiver, and M is visible satellite number;

The idiographic flow of described step (2) is:

(2.1) visible satellite position and receiver general location are the vector of ECEF coordinate system, and the position of j visible satellite is X ^j=[x ^jy ^jz ^j] and receiver general location be X ₀=[x ₀y ₀z ₀], coefficient matrices A computing formula is:

Wherein, for the direction cosine of receiver to satellite j observation vector, specific formula for calculation be:

$e_x^j=\frac{x_0-x^j}{\sqrt{{(x_0-x^j)}^2+{(y_0-y^j)}^2+{(z_0-z^j)}^2}}$

$e_y^j=\frac{y_0-y^j}{\sqrt{{(x_0-x^j)}^2+{(y_0-y^j)}^2+{(z_0-z^j)}^2}}$

$e_z^j=\frac{z_0-z^j}{\sqrt{{(x_0-x^j)}^2+{(y_0-y^j)}^2+{(z_0-z^j)}^2}}$

(2.2) weight coefficient matrix Q is:

Q=(A ^TA)- ¹。

3. the usable satellite fast selecting method based on multimode GNSS receiver according to claim 2, is characterized in that, in described step (3), the formula that calculates GDOP value according to weight coefficient matrix Q is:

$\mathrm{GDOP}=\sqrt{\mathrm{trace}\left(Q\right)}=\sqrt{\mathrm{trace}\left({\left(A^{T}A\right)}^{-1}\right)}$

Wherein, the mark of trace (Q) representing matrix Q, is matrix Q diagonal entry sum.

4. the usable satellite fast selecting method based on multimode GNSS receiver according to claim 3, is characterized in that, the idiographic flow of described step (4) is:

(4.1) calculate the contribution margin △ G of every visible satellite to GDOP _i:

${\mathrm{\ΔG}}_i={\mathrm{GDOP}}_{M-1}^i-{\mathrm{GDOP}}_M$

Wherein, GDOP _mfor adopting M the GDOP value that visible satellite observed reading calculates, for adopting M-1 and do not comprise the GDOP value that i visible satellite calculates;

(4.2) the △ G to M satellite _ivalue, arranges and forms S set according to order from big to small _g:

S _G={s _i|△G _i≥△G _i-1,1≤i≤M}。

5. the usable satellite fast selecting method based on multimode GNSS receiver according to claim 4, is characterized in that, in described step (5), selected visible satellite set is

S _N={s _i|△G _i≥△G _i-1,(M-N+1)≤i≤M}

S _nbe N visible satellite combination of GDOP minimum, corresponding visible satellite subset is the usable satellite constellation of selection.