CN103364801B - A method for multiplying positioning precision in a satellite navigation positioning system - Google Patents

Abstract

The invention discloses a method for multiplying positioning precision in a satellite navigation positioning system. In the method, each navigational satellite in the satellite navigation positioning system downloads pseudo stochastic noise codes, navigation messages, and wide-area enhanced information via multiple carrier frequency points; a user terminal measures and corrects the track errors of the navigational satellites, ionosphere time delay, troposphere time delay, and multipath errors simultaneously and individually with the multiple carrier frequency points in order to achieve pseudo range measurement between the navigational satellites and the user terminal on the multiple carrier frequency points; and by using a pseudo range observational equation of the multiple carrier frequency points, the accurate coordinate of the position of the user terminal can be calculated via iterative computations. The method is capable of well increasing the positioning precision of the user terminal and substantially improving the navigation positioning performance of the satellite navigation positioning system.

Description

The method of the positioning precision that doubles in a kind of satellite navigation and location system

Technical field

The present invention relates to Technique of Satellite Navigation and Positioning, the method of the positioning precision that doubles in especially a kind of satellite navigation and location system, being applicable to a Navsat can simultaneously descending multiple carrier frequency point, and modulates the multifrequency satellite navigational system of Pseudo-Random Noise Code and navigation message.

Background technology

In satellite navigation and location system, the positioning precision of user terminal determines primarily of the space layout of system constellation and equivalent pseudo range measurement error.Under normal circumstances, the positioning error of satellite navigation and location system can describe with following formula:

σ _i＝DOP _i·σ _UERE(1)

Wherein, σ _ifor the positioning error of user terminal, i=1,2,3,4,5 corresponding flat, elevation, position, clock correction and general orientation error respectively; DOP _ifor the geometric dilution of precision of system constellation, DOP ₁, DOP ₂, DOP ₃, DOP ₄and DOP ₅corresponding HDOP, VDOP, PDOP, TDOP and GDOP (plane, elevation, position, clock correction and total geometric dilution of precision) respectively; σ _uEREfor equivalent pseudo range measurement error.Formula (1) requires that the pseudo range measurement error of Navsat meets the following conditions: 1. separate; 2. equal distribution; 3. the Gaussian distribution of zero-mean is obeyed.

In global navigation satellite system, a lot of Navsat can modulate Pseudo-Random Noise Code and navigation message on multiple carrier frequency point.2002, the Chinese Academy of Sciences Chinese mugwort auspicious academician of state heads the list of signers to have invented the satellite navigation and location system (patent No.: the ZL 200410046064.1 based on telstar, denomination of invention: transponder satellite communication navigation positioning system, inventor: Ai Guoxiang, execute that waterside is vertical, Wu Haitao, on July 29th, 2009 obtains the authorization).This invention uses the multiple communication frequencies on telstar as navigation, open the new beginning that full range Communication Development becomes full range navigation.Observe pseudorange and the Doppler shift of a Navsat simultaneously, can user terminal be tied on the base circumference of a circular cone, need the pseudo-range measurements of more than two (containing two) Navsats and Doppler shift measurement value just can realize the navigator fix (application number: 201110164385.1 of user terminal, denomination of invention: in conjunction with the localization method of Doppler range rate measurement in satellite navigation, inventor: Ma Lihua, Ai Guoxiang, Ji Haifu).If every Navsat descending multiple pilot carriers simultaneously, effectively can reduce the equivalent pseudo range measurement error of this Navsat, improve the navigation and positioning accuracy (application number: 201110228917.3 of user terminal, denomination of invention: the localization method of multicarrier in satellite navigation, inventor: Ma Lihua, Ai Guoxiang, Ji Haifu).

Generally, there is relevant portion in pseudo-range measurements and the satellite ephemeris of multiple carrier frequency points of same Navsat, and now the positioning precision of user terminal can not use formula (1) to estimate; Simultaneously, in existing global navigation satellite system, every Navsat can be simultaneously descending carrier frequency point quantity not identical, simply can not apply mechanically invention: the localization method (number of patent application: the method reducing pseudo range measurement error 201110228917.3) of multicarrier in satellite navigation.The method of the positioning precision that doubles in satellite navigation and location system of the present invention, from physical layer, to having utilized the positioning precision of multiple carrier frequency point multiplicative user terminal to do, brand-new science is set forth, and can be used for instructing in multi-frequency-point satellite navigation positioning system, utilize carrier frequency point resource to carry out the positioning precision of multiplicative user terminal.

Summary of the invention

The object of this invention is to provide the method for the positioning precision of multiplicative user terminal in a kind of satellite navigation and location system, utilize the multiple carrier frequency point of Navsat in satellite navigation and location system to work simultaneously, user terminal is by the independent measurement simultaneously of multiple carrier frequency point and correct orbit error and clock correction, the ionospheric delay of Navsat, troposphere time delay, Multipath Errors, realize Navsat on multiple carrier frequency point and, to the pseudo range measurement of user terminal, finally determine the accurate coordinate of user terminal location.

The present invention proposes in a kind of satellite navigation and location system the method for the positioning precision that doubles, it comprises the physical meaning of two aspects: on the one hand: the navigation signal of every all descending N number of carrier frequency point of Navsat in satellite navigation and location system, and at this moment the measurement noises of navigation signal is reduced to single carrier frequency measurement noises n number of carrier frequency point is utilized to measure respectively and Navsat orbit error after correcting and clock correction are incoherent; Utilize multiple carrier frequency point to correct ionospheric delay and troposphere time delay, its residual error is also reduced to accordingly n number of carrier frequency point is utilized to correct the Multipath Errors of user terminal respectively.Finally, the residual error in the pseudo range measurement after multiple carrier frequency point corrects is uncorrelated mutually.Therefore, for every Navsat, utilize N number of carrier frequency point to measure respectively and pseudo-range measurements after correcting, all there is random character, meet the service condition of formula (1).When using multiple carrier frequency point, formula (1) can be rewritten as:

σ _i＝DOP _i·PAFP·σ _UERE(2)

Wherein, PAFP is that same Navsat uses multiple carrier frequency point to the enhancer of positioning precision, be called physical accuracy enhancer, the numerical value of PAFP depend on the descending carrier frequency of every Navsat count and Navsat relative to the geometry of user terminal.For the purpose of directly perceived, supposing that the descending carrier frequency of every Navsat is counted is all N, now, on the other hand: while the pseudorange measuring same Navsat, can Doppler shift on measure and navigation satellite on multiple carrier frequency point, namely corresponding pseudorange rate of change information is provided, when setting up observation equation group and solving the position of user terminal, Doppler shift measurement and pseudo range measurement have equivalence.Therefore, if measure pseudorange and Doppler shift on multiple carrier frequency point simultaneously, PAFP numerical value can also reduce in theory further

DOP is the geometric parameter in space, and the pseudorange measured on multiple carrier frequency point a Navsat and Doppler shift are all physical parameters, therefore, the present invention proposes independent factor PAFP to the enhancing of the positioning precision evaluated multiple carrier frequency point measurement and cause.Be not difficult to find out, PAFP is a kind of physical accuracy enhancer, and independent of one another with geometric parameter DOP, both are uncorrelated mutually on the impact of user terminal positioning precision.

In order to achieve the above object, the present invention proposes to double in a kind of satellite navigation and location system the method for positioning precision, and be applicable to the high-precision point location of user terminal, it is characterized in that, the method comprises the following steps:

Step 1, the navigation signal for navigator fix that each Navsat in the M of a satellite navigation and location system inside Navsat will send to user terminal to be positioned is modulated to multiple carrier frequency point, wherein, M >=4, described navigation signal comprises Pseudo-Random Noise Code, navigation message and wide area and strengthens information;

Step 2, sends described Pseudo-Random Noise Code and navigation message downwards with multiple carrier frequency point;

Step 3, user terminal receives by multiple carrier frequency point the described Pseudo-Random Noise Code and navigation message that all Navsats issue;

Step 4, the clock that user terminal obtains Navsat according to the described navigation message received corrects parameter; According to the Navsat ephemeris in the described navigation message received, obtain the orbital position of Navsat; The orbit error of Navsat is corrected according to the described navigation signal received; User terminal obtains each Navsat on each carrier frequency point according to Pseudo-Random Noise Code and, to the measurement pseudorange of user terminal, corrects ionospheric delay, troposphere time delay and the Multipath Errors in measurement pseudorange according to the described navigation signal received;

Step 5, user terminal is according to the measurement pseudorange having corrected ionospheric delay, troposphere time delay and Multipath Errors, and the satellite orbital position after correcting carries out Iterative to the position coordinates of user terminal, finally obtains the accurate coordinate of user terminal location;

Step 6, uses the positioning precision of physical accuracy enhancer to user terminal to evaluate.

Method of the present invention can be good at the positioning precision improving user terminal, significantly can improve the navigator fix performance of system.

Accompanying drawing explanation

Fig. 1 is the method flow diagram of positioning precision of doubling in satellite navigation and location system of the present invention.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.

Fig. 1 is the method flow diagram of positioning precision of doubling in satellite navigation and location system of the present invention.As shown in Figure 1, the method for the positioning precision that doubles in a kind of satellite navigation and location system proposed by the invention specifically comprises the following steps:

Step 1, the navigation signal for navigator fix that each Navsat in M (M >=4) Navsat of satellite navigation and location system inside will send to user terminal to be positioned is modulated to multiple carrier frequency point, and described navigation signal comprises Pseudo-Random Noise Code, navigation message and wide area and strengthens information;

Described Pseudo-Random Noise Code corresponds to each Navsat separately, Pseudo-Random Noise Code can be used for identifying Navsat, utilize the auto-correlation of Pseudo-Random Noise Code and their cross correlation to realize the time difference measurements of navigation signal transmission, this mistiming is multiplied by wave transmissions speed and is the pseudorange of Navsat to user terminal; Described navigation message includes system time, the clock of Navsat corrects parameter, ionospheric delay model parameter, Navsat ephemeris and satellite health; Described wide area strengthens correction data and the integrity information that packets of information contains Navsat track.

M (M >=4) Navsat descending multiple carrier frequency point all simultaneously of described satellite navigation and location system inside, and Pseudo-Random Noise Code and navigation message is modulated on this multiple carrier frequency point, the quantity of the carrier frequency point that different Navsats uses is likely different.

User terminal in the present invention can be fixed terminal or mobile terminal, and described fixed terminal is fixed satellite receiving equipment; Described mobile terminal is vehicle-mounted, boat-carrying or hand-held receiving equipment.

Step 2, sends described Pseudo-Random Noise Code and navigation message downwards with multiple carrier frequency point;

Step 3, user terminal receives by multiple carrier frequency point the described Pseudo-Random Noise Code and navigation message that all Navsats issue;

Step 4, the clock that user terminal obtains Navsat according to the described navigation message received corrects parameter; According to the Navsat ephemeris in the described navigation message received, obtain the orbital position of Navsat; The orbit error of Navsat is corrected according to the described navigation signal received; User terminal obtains each Navsat on each carrier frequency point according to Pseudo-Random Noise Code and, to the measurement pseudorange of user terminal, corrects ionospheric delay, troposphere time delay and the Multipath Errors in measurement pseudorange according to the described navigation signal received;

Particularly:

User terminal corrects the orbit error of data correction Navsat according to the satellite orbit in the described wide area enhancing information received;

User terminal obtains each Navsat on each carrier frequency point according to Pseudo-Random Noise Code:

At measurement moment t _k, user terminal measurement obtains i-th (i=1,2 ..., N _j) the Navsat S of individual frequency _jto the measurement pseudorange of user terminal this measurement pseudorange meets following pseudorange observation equation simultaneously:

${\mathrm{\ρ}}_k^{j,i}={[{(X^j-X_k)}^2+{(Y^j-Y_k)}^2+{(Z^j-Z_k)}^2]}^{1/2}$

$+b_k-{\mathrm{c\δt}}^j+{\mathrm{\δ\ρ}}_{k_n}^{j,i}+{\mathrm{\δ\ρ}}_{k_P}^{j,i}+v_k^{j,i}---\left(3\right)$

$(j=\mathrm{1,2},...,M;i=\mathrm{1,2},...,N_j)$

In formula, for measuring pseudorange; (X _k, Y _k, Z _k) for user terminal to be positioned is at t _kaccurate coordinate (amount to be asked); (X ^j, Y ^j, Z ^j) be Navsat S _jposition coordinates when launching navigation signal; b _kfor the equivalent distances (amount to be asked) of user terminal clock correction; δ t ^jfor the clock of Navsat corrects parameter, obtain the navigation message that can send from Navsat; C is vacuum light speed, for the ionospheric delay before correction, for the troposphere time delay before correction, for stochastic error.

User terminal corrects the ionospheric delay measured in pseudorange according to the ionospheric delay model parameter in ionospheric delay model and the described navigation message that receives; User terminal gathers local meteorologic parameter, and according to the orbital position of Navsat, utilizes tropospheric delay to correct the troposphere time delay measured in pseudorange; According to the environmental aspect of locality, utilize multipath correction model to correct the Multipath Errors measured in pseudorange.

Step 5, user terminal is according to the measurement pseudorange having corrected ionospheric delay, troposphere time delay and Multipath Errors, and the satellite orbital position after correcting carries out Iterative to the position coordinates of user terminal, finally obtains the accurate coordinate of user terminal location;

Described step 5 is further comprising the steps:

Step 5.1, user terminal is positioned resolve time, first set the initial value of a user terminal location coordinate, i.e. the general location coordinate (X of user terminal _k ⁰, Y _k ⁰, Z _k ⁰);

Step 5.2, then carries out 1 rank Taylor series expansion to the pseudorange observation equation shown in formula (3), obtains the linearised form containing user terminal location coordinate modification step-length, described pseudorange observation equation:

$v_k^{j,i}=l_k^j{\mathrm{\δX}}_k+m_k^j{\mathrm{\δY}}_k+n_k^j{\mathrm{\δZ}}_k---\left(4\right)$

$-b_k+{\mathrm{\ρ}}_k^{j,i}-{R_k}^j+{\mathrm{c\δt}}^j-{\mathrm{\δ\ρ}}_{k_n}^{j,i}-{\mathrm{\δ\ρ}}_{k_P}^{j,i}$

In formula, (δ X _k, δ Y, δ Z _k) be the correction step-length of user terminal location coordinate, for the general location coordinate of user terminal is to Navsat S _jdirection cosine:

$l_k^j=\frac{X^j-{X_k}^0}{{R_k}^j},$ $m_k^j=\frac{Y^j-{Y_k}^0}{{R_k}^j},$ $n_k^j=\frac{Z^j-{Z_k}^0}{{R_k}^j}---\left(5\right)$

R _k ^jfor the general location coordinate of user terminal is to Navsat S _jdistance:

R _k ^j＝[(X ^j-X _k ⁰) ²+(Y ^j-Y _k ⁰) ²+(Z ^j-Z _k ⁰) ²] ^1/2(6)

According to position coordinates and the clock corrected value of the Navsat of navigation signal x time, the general location coordinate through type (5) of user terminal and (6) are utilized to calculate the general location coordinate of user terminal to Navsat S _jdirection cosine with the general location coordinate of user terminal to Navsat S _jgeometric distance R _k ^j.

Step 5.3, solves the linearization pseudorange observation equation that described step 5.2 obtains, obtains the correction step-length of user terminal location coordinate;

Described step 5.3 is further comprising the steps:

Step 5.3.1, uses the known terms in described linearization pseudorange observation equation (4) represent, have:

$v_k^{j,i}=l_k^j{\mathrm{\δX}}_k+m_k^j{\mathrm{\δY}}_k+n_k^j{\mathrm{\δZ}}_k-b_k-L_k^{j,i}---\left(7\right)$

In formula, constant term for described linearization pseudorange observation equation:

$L_k^{j,i}={R_k}^j-{\mathrm{\ρ}}_k^{j,i}-{\mathrm{c\δt}}^j+{\mathrm{\δ\ρ}}_{k_n}^{j,i}+{\mathrm{\δ\ρ}}_{k_P}^{j,i}---\left(8\right)$

Step 5.3.2, is write formula (7) as matrix form:

V＝AX-L (9)

In formula, X is undetermined parameter vector:

X＝[δX _kδY _kδZ _kb _k] ^T(10)

A is the matrix of coefficients of undetermined parameter:

Wherein, each Navsat S _ja corresponding N in matrix A _jthe submatrix that row 4 arranges.

L is constant term vector:

$L={\left[\begin{array}{ccccccccccc}{L}_k^{\mathrm{1,1}}& ...& L_k^{1,N_1}& L_k^{\mathrm{2,1}}& ...& L_k^{2,N_2}& ...& ...& L_k^{M,1}& ...& L_k^{M,N_M}\end{array}\right]}^T---\left(12\right)$

V is stochastic error vector:

$V={\left[\begin{array}{ccccccccccc}{v}_k^{\mathrm{1,1}}& ...& v_k^{1,N_1}& v_k^{\mathrm{2,1}}& ...& v_k^{2,N_2}& ...& ...& v_k^{M,1}& ...& v_k^{M,N_M}\end{array}\right]}^T---\left(13\right)$

Step 5.3.3, utilizes least square method to solve formula (9), can obtain undetermined parameter vector X:

X＝(A ^TA) ^-1A ^TL (14)

Step 5.4, the general location coordinate of correction step-length to user terminal of the user terminal location coordinate using described step 5.3 to obtain is revised;

Undetermined parameter vector X formula (14) calculated brings following formula into, revises the general location coordinate of user terminal:

$\left\{\begin{array}{c}{X}_k={X_k}^0+{\mathrm{\δX}}_k\\ Y_k={Y_k}^0+{\mathrm{\δY}}_k\\ Z_k={Z_k}^0+{\mathrm{\δZ}}_k\end{array}\right.---\left(15\right)$

Step 5.5, the position coordinates of revised user terminal is carried out iterative computation as the general location coordinate repetition step 5.2-step 5.4 of user terminal, until meet iteration termination condition, the position coordinates of the user terminal now obtained is the accurate coordinate of user terminal location.

According to the needs of practical application, described iteration termination condition can require (such as maximum iterations is 5 times) or accuracy requirement (such as, the difference of twice each coordinate figure of iteration is less than a certain fixed value, such as 0.5 meter) for number of times.

Step 6, uses the positioning precision of physical accuracy enhancer to user terminal to evaluate.

In this step, geometric accuracy damping matrix Q is first introduced:

$Q={\left(A^{T}A\right)}^{-1}=\left[\begin{array}{cccc}{D}_{11}& D_{12}& D_{13}& D_{14}\\ D_{21}& D_{22}& D_{23}& D_{24}\\ D_{31}& D_{32}& D_{33}& D_{34}\\ D_{41}& D_{42}& D_{43}& D_{44}\end{array}\right]---\left(16\right)$

Further, obtain:

${\mathrm{DOP}}_1=\sqrt{D_{11}+D_{22}},$ ${\mathrm{DOP}}_2=\sqrt{D_{33}},$ ${\mathrm{DOP}}_3=\sqrt{D_{11}+D_{22}+D_{33}},$

${\mathrm{DOP}}_4=\sqrt{D_{44}},$ ${\mathrm{DOP}}_5=\sqrt{D_{11}+D_{22}+D_{33}+D_{44}}---\left(17\right)$

DOP _ifor the geometric dilution of precision of multi-frequency-point satellite navigation location constellation, i=1,2,3,4,5 corresponding flat (HDOP), elevation (VDOP), position (PDOP), clock correction (TDOP) and total geometric dilution of precision (GDOP) respectively.

During every Navsat employing single carrier frequency, the N namely in formula (11) _j=1 (j=1,2 ..., M), be designated as DOP according to the geometric dilution of precision that formula (16) and (17) obtain ₀, then physical accuracy enhancer PAFP may be defined as:

$\mathrm{PAFP}=\frac{{\mathrm{DOP}}_i}{{\mathrm{DOP}}_0}---\left(18\right)$

Utilize physical accuracy enhancer PAFP, the positioning error of user terminal can be described as:

σ _i＝DOP _i·PAFP·σ _UERE(19)

Wherein, σ _ifor the positioning error of user terminal, σ _uEREfor equivalent pseudo range measurement error.

Except the localization method of the above-mentioned pseudo range measurement based on multiple carrier frequency point, described physical accuracy enhancer PAFP also can be used for the evaluation of the localization method for the Doppler shift measurement based on multiple carrier frequency point.In general, the present invention is a kind of physical method of the positioning precision that doubles.

Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (8)

1. a method for the positioning precision that doubles in satellite navigation and location system, the high-precision point for user terminal is located, and it is characterized in that, the method comprises the following steps:

Step 1, the navigation signal for navigator fix that each Navsat in the M of a satellite navigation and location system inside Navsat will send to user terminal to be positioned is modulated to multiple carrier frequency point, wherein, M >=4, described navigation signal comprises Pseudo-Random Noise Code, navigation message and wide area and strengthens information;

Step 2, sends described Pseudo-Random Noise Code and navigation message downwards with multiple carrier frequency point;

Step 3, user terminal receives by multiple carrier frequency point the described Pseudo-Random Noise Code and navigation message that all Navsats issue;

Step 4, the clock that user terminal obtains Navsat according to the described navigation message received corrects parameter; According to the Navsat ephemeris in the described navigation message received, obtain the orbital position of Navsat; The orbit error of Navsat is corrected according to the described navigation signal received; User terminal obtains each Navsat on each carrier frequency point according to Pseudo-Random Noise Code and, to the measurement pseudorange of user terminal, corrects ionospheric delay, troposphere time delay and the Multipath Errors in measurement pseudorange according to the described navigation signal received;

Step 5, user terminal is according to the measurement pseudorange having corrected ionospheric delay, troposphere time delay and Multipath Errors, and the satellite orbital position after correcting carries out Iterative to the position coordinates of user terminal, finally obtains the accurate coordinate of user terminal location;

Step 6, use the positioning precision of physical accuracy enhancer to user terminal to evaluate, described physical accuracy enhancer PAFP is defined as:

$\mathrm{PAFP}=\frac{{\mathrm{DOP}}_i}{{\mathrm{DOP}}_0},$

Wherein, DOP _ifor the geometric dilution of precision of multi-frequency-point satellite navigation location constellation, i=1,2,3,4,5 corresponding flat, elevation, position, clock correction and total geometric dilution of precision respectively:

${\mathrm{DOP}}_1=\sqrt{D_{11}+D_{22}},{\mathrm{DOP}}_2=\sqrt{D_{33}},{\mathrm{DOP}}_3=\sqrt{D_{11}+D_{22}+D_{33}},$

${\mathrm{DOP}}_4=\sqrt{D_{44}},{\mathrm{DOP}}_5=\sqrt{D_{11}+D_{22}+D_{33}+D_{44}},$

Wherein, D ₁₁, D ₂₂, D ₃₃, D ₄₄for the diagonal entry of geometric accuracy damping matrix Q, described geometric accuracy damping matrix Q is expressed as:

$Q={\left(A^{T}A\right)}^{-1}=\left[\begin{array}{cccc}{D}_{11}& D_{12}& D_{13}& D_{14}\\ D_{21}& D_{22}& D_{23}& D_{24}\\ D_{31}& D_{32}& D_{33}& D_{34}\\ D_{41}& D_{42}& D_{43}& D_{44}\end{array}\right],$

DOP ₀for geometric dilution of precision during every Navsat employing single carrier frequency;

Wherein, the positioning error of the user terminal utilizing described physical accuracy enhancer PAFP to obtain is:

σ _i＝DOP _i·PAFP·σ _UERE，

Wherein, σ _ifor the positioning error of user terminal, σ _uEREfor equivalent pseudo range measurement error.

2. method according to claim 1, is characterized in that, described Pseudo-Random Noise Code corresponds to each Navsat separately, can identify Navsat; Utilize the auto-correlation of described Pseudo-Random Noise Code and their cross correlation to carry out the mistiming of measure and navigation Signal transmissions, this mistiming is multiplied by wave transmissions speed and is the measurement pseudorange of Navsat to user terminal; Described navigation message includes system time, the clock of Navsat corrects parameter, ionospheric delay model parameter, Navsat ephemeris and satellite health; Described wide area strengthens correction data and the integrity information that packets of information contains Navsat track.

3. method according to claim 2, is characterized in that, described measurement pseudorange meets following pseudorange observation equation simultaneously:

$\begin{array}{c}{\mathrm{\ρ}}_k^{j,i}={[{(X^j-X_k)}^2+{(Y^j-Y_k)}^2+{(Z^j-Z_k)}^2]}^{1/2}\\ +b_k-{\mathrm{c\δt}}^j+{\mathrm{\δ\ρ}}_{k_n}^{j,i}+{\mathrm{\δ\ρ}}_{k_P}^{j,i}+v_k^{j,i}\\ (j=\mathrm{1,2},...,M;i=\mathrm{1,2},...,N_j)\end{array},$

Wherein, for measuring moment t _k, the Navsat S at i-th frequency that user terminal measurement obtains _jto the measurement pseudorange of user terminal, i=1,2 ..., N _j, j=1,2 ..., M; (X _k, Y _k, Z _k) for user terminal to be positioned is at moment t _kaccurate coordinate; (X ^j, Y ^j, Z ^j) be Navsat S _jposition coordinates when launching navigation signal; b _kfor the equivalent distances of user terminal clock correction; δ t ^jfor the clock of Navsat corrects parameter; C is vacuum light speed, for the ionospheric delay before correction, for the troposphere time delay before correction, for stochastic error.

4. method according to claim 1, is characterized in that, described step 4 comprises further: the orbit error correcting data correction Navsat according to the satellite orbit in the described wide area enhancing information received; The ionospheric delay measuring pseudorange is corrected according to the ionospheric delay model parameter in ionospheric delay model and the described navigation message that receives; User terminal gathers local meteorologic parameter, and according to the orbital position of Navsat, utilizes tropospheric delay to correct the troposphere time delay measuring pseudorange; According to the environmental aspect of locality, utilize multipath correction model to correct the Multipath Errors measuring pseudorange.

5. method according to claim 3, is characterized in that, described step 5 is further comprising the steps:

Step 5.1, first sets the general location coordinate (X of initial value as user terminal of a user terminal location coordinate _k ⁰, Y _k ⁰, Z _k ⁰);

Step 5.2, then carries out 1 rank Taylor series expansion to described pseudorange observation equation, obtains the linearised form containing user terminal location coordinate modification step-length, described pseudorange observation equation;

Step 5.3, solves the linearization pseudorange observation equation that described step 5.2 obtains, obtains the correction step-length of user terminal location coordinate;

Step 5.4, the general location coordinate of correction step-length to user terminal of the user terminal location coordinate using described step 5.3 to obtain is revised;

Step 5.5, the position coordinates of revised user terminal is carried out iterative computation as the general location coordinate repetition step 5.2-step 5.4 of user terminal, until meet iteration termination condition, the position coordinates of the user terminal now obtained is the accurate coordinate of user terminal location, and described iteration termination condition is number of times requirement or accuracy requirement.

6. method according to claim 5, is characterized in that, the linearised form of described pseudorange observation equation is:

$\begin{array}{c}{v}_k^{j,i}=l_k^i\mathrm{\δ}{X}_k+m_k^j\mathrm{\δ}{Y}_k+n_k^j\mathrm{\δ}{Z}_k\\ -b_k+{\mathrm{\ρ}}_k^{j,i}-{R_k}^j+c{\mathrm{\δt}}^j-\mathrm{\δ}{\mathrm{\ρ}}_{k_n}^{j,i}-\mathrm{\δ}{\mathrm{\ρ}}_{k_P}^{j,i}\end{array},$

Wherein, (δ X _k, δ Y, δ Z _k) be the correction step-length of user terminal location coordinate, for the general location coordinate of user terminal is to Navsat S _jdirection cosine:

$l_k^j=\frac{X^j-{X_k}^0}{{R_k}^j},m_k^j=\frac{Y^j-{Y_k}^0}{{R_k}^j},n_k^j=\frac{Z^j-{Z_k}^0}{{R_k}^j},$

R _k ^jfor the general location coordinate of user terminal is to Navsat S _jdistance:

R _k ^j＝[(X ^j-X _k ⁰) ²+(Y ^j-Y _k ⁰) ²+(Z ^j-Z _k ⁰) ²] ^1/2。

7. method according to claim 6, is characterized in that, described step 5.3 is further comprising the steps:

Step 5.3.1, uses the known terms in linearizing pseudorange observation equation represent:

$v_k^{j,i}=l_k^j{\mathrm{\δX}}_k+m_k^j{\mathrm{\δY}}_k+n_k^j\mathrm{\δ}{Z}_k-b_k-L_k^{j,i},$

Wherein, $L_k^{j,i}={R_k}^j-{\mathrm{\ρ}}_k^{j,i}-c{\mathrm{\δt}}^j+{\mathrm{\δ\ρ}}_{k_n}^{j,i}+\mathrm{\δ}{\mathrm{\ρ}}_{k_P}^{j,i};$

Step 5.3.2, is write above formula as matrix form:

V＝AX-L，

Wherein, X is undetermined parameter vector:

X＝[δX _kδY _kδZ _kb _k] ^T，

A is the matrix of coefficients of undetermined parameter:

$A=\left[\begin{array}{c}{\left[\begin{array}{cccc}{l}_k^1& m_k^1& n_k^1& -1\\ ...& ...& ...& ...\\ l_k^1& m_k^1& n_k^1& -1\end{array}\right]}_{(N_1\×4)}\\ {\left[\begin{array}{cccc}{l}_k^2& m_k^2& n_k^2& -1\\ ...& ...& ...& ...\\ l_k^2& m_k^2& n_k^2& -1\end{array}\right]}_{(N_2\×4)}\\ ............\\ ............\\ {\left[\begin{array}{cccc}{l}_k^j& m_k^j& n_k^j& -1\\ ...& ...& ...& ...\\ l_k^j& m_k^j& n_k^j& -1\end{array}\right]}_{(N_j\×4)}\\ ............\\ ............\\ {\left[\begin{array}{cccc}{l}_k^M& m_k^M& n_k^M& -1\\ ...& ...& ...& ...\\ l_k^M& m_k^M& n_k^M& -1\end{array}\right]}_{(N_M\×)}\end{array}\right],$

Each Navsat S _ja corresponding N in matrix A _jthe submatrix that row 4 arranges,

L is constant term vector:

$L={\left[\begin{array}{ccccccccccc}{L}_k^{\mathrm{1,1}}& ...& L_k^{1,N_1}& L_k^{\mathrm{2,1}}& ...& L_k^{2,N_2}& ...& ...& L_k^{M,1}& ...& L_k^{M,N_M}]\end{array}\right]}^T,$

V is stochastic error vector:

$V={\left[\begin{array}{ccccccccccc}{v}_k^{\mathrm{1,1}}& ...& v_k^{1,N_1}& v_k^{\mathrm{2,1}}& ...& v_k^{2,N_2}& ...& ...& v_k^{M,1}& ...& v_k^{M,N_M}]\end{array}\right]}^T;$

Step 5.3.3, utilizes the linearization pseudorange observation equation of least square method solution matrix form, obtains undetermined parameter vector X:

X＝(A ^TA)- ¹A ^TL。

8. method according to claim 1, is characterized in that, described user terminal is fixed terminal or mobile terminal, and described fixed terminal is fixed satellite receiving equipment, and described mobile terminal is vehicle-mounted, boat-carrying or hand-held receiving equipment.