CN102830410A - Positioning method in combination with Doppler velocity measurement in satellite navigation - Google Patents

Abstract

The invention discloses a positioning method in combination with Doppler velocity measurement in satellite navigation, and relates to the satellite navigation positioning technology. The positioning method comprises: (a) at least two navigational satellites respectively downlink modulate a path of navigation signal; (b) a user terminal receives the path of downlink navigation signal of each navigational satellite and respectively measures the pseudo range of each navigational satellite; (c) at the same time, the user terminal measures Doppler velocity relative to each navigational satellite; and (d) the user terminal realizes navigational positioning by utilizing the observation pseudo range of each navigational satellite and Doppler velocity measurement information obtained in (b) and (c). According to the method, by combination of the Doppler velocity measurement information, the requirement that the quantity of satellites in a satellite navigation system is not less than 4 is reduced, and higher-precision navigational positioning can be realized.

Description

The localization method that combines Doppler range rate measurement in the satellite navigation

Technical field

The present invention relates to satellite navigation positioning technical field, is the localization method that combines Doppler range rate measurement in a kind of satellite navigation, is particularly useful for number of satellite satellite navigation system seldom, has improved the navigator fix performance of system.

Background technology

Generally, in satellite navigation and location system, user terminal need be observed 4 (containing) above satellites simultaneously, could realize that three-dimensional localization and clock correction finds the solution.For the less satellite navigation system of number of satellite, if can realizing locating, utilization satellite seldom finds the solution, then can shorten the establishment cycle of system, reduce the cost of establishment system significantly.

Doppler range rate measurement can provide more metrical information for user terminal, in conjunction with the result that tests the speed, can reduce the restriction of satellite navigation system to Navsat quantity.

Summary of the invention

The objective of the invention is to disclose in a kind of satellite navigation the localization method that combines Doppler range rate measurement, improving user's bearing accuracy,, number of satellite not good in the satellite constellation layout in conjunction with the Doppler range rate measurement of satellite, confirmed the position of user terminal more after a little while.

In order to achieve the above object, technical solution of the present invention is:

Combine the localization method of Doppler range rate measurement in a kind of satellite navigation, it comprises step:

A) at least 2 Navsats, descending modulation one road navigation signal respectively;

B) user terminal receives every road navigation signal that Navsat is descending, measures the pseudorange of every Navsat respectively;

C) simultaneously, user terminal measurement is with respect to the doppler velocity of every Navsat;

D) user terminal utilizes b), c) observation pseudorange and the Doppler range rate measurement information of step gained every Navsat, the realization navigator fix.

The localization method of described combination Doppler range rate measurement, its said a) in navigation signal, comprise the ranging code and the numeric data code of carrier wave.

The localization method of described combination Doppler range rate measurement, its said d) the middle user terminal navigator fix of realizing is to the equation group:

$v_k^j=l_k^j\mathrm{\δ}{X}_k+m_k^j\mathrm{\δ}{Y}_k+n_k^j{\mathrm{\δZ}}_k-b_k-L_k^j$

$e_u\·e_j=\frac{v_{\mathrm{rel}}}{v_j}$

Utilize least square method to solve unknown parameter vector Δ X, wherein Δ X=[δ X _kδ Y _kδ Z _kb _k] ^T, obtain the user coordinates coordinate through iteration repeatedly, further convert rectangular space coordinate into the earth longitude and latitude and the geodetic height of user terminal again;

Wherein, Be the constant term of observational error equation, e _uWith e _jBe unit vector, v _RelBe actual measurement speed, v _jBe satellite velocities.

The localization method of described combination Doppler range rate measurement, the fixed point coordinate of its said user terminal is constrained on satellite S _jBe summit, pseudorange

On the cone face for bus.

The localization method of described combination Doppler range rate measurement, its said user terminal is fixed terminal or portable terminal.

The localization method of described combination Doppler range rate measurement, its said fixed terminal is the fixed satellite receiving equipment; Portable terminal is vehicle-mounted, boat-carrying or hand-held receiving equipment.

Method of the present invention is suitable for the very high satellite navigation system of Doppler range rate measurement precision especially, and, number of satellite not good in the satellite constellation layout can be good at improving the bearing accuracy of user terminal more after a little while.

Description of drawings

The setting circle conical surface synoptic diagram that Fig. 1 confirms for Doppler range rate measurement in the localization method that combines Doppler range rate measurement in the satellite navigation of the present invention.

Embodiment

Combine the localization method of Doppler range rate measurement to relate to Navsat and user terminal in the satellite navigation of the present invention.

Navsat: descending one tunnel navigation carrier wave of satellite that satellite navigation system is inner, modulation ranging code and numeric data code on the carrier wave.

User terminal: the navigation signal that demodulation of satellite is descending, realize pseudo range measurement and the Doppler range rate measurement of satellite to user terminal.Division is following:

Pseudorange observation equation: demodulation of satellite S _j(j=1,2 ..., n) descending navigation signal is realized the pseudo range measurement of satellite to user terminal.At t _kConstantly, user's observation obtains satellite S _jPseudorange

(j=1,2 ..., n), can get the pseudorange observation equation:

${\mathrm{\ρ}}_k^j=[{(X^j-X_k)}^2+{(Y^j-Y_k)}^2+{(Z^j-Z_k)}^2{]}^{1/2}+b_k-{\mathrm{c\δt}}^j---\left(1\right)$

$(j=\mathrm{1,2},\·\·\·,n)$

In the formula,

The pseudorange that obtains for observation; (X _k, Y _k, Z _k) be that user terminal is being measured t constantly _kCoordinate; (X ^j, Y ^j, Z ^j) be satellite S _jCoordinate when the emission navigation signal; b _kBe receiver clock correction equivalent distances; δ t ^jFor satellite clock clock correction corrects, but try to achieve in the self-conductance avionics literary composition; C is the light velocity in the vacuum.

Consider ionospheric delay

tropospheric delay

and observation random error there is observational error equation:

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

(2)

$b_k-{\mathrm{c\δt}}^j+{\mathrm{\δ\ρ}}_{k_n}^j+{\mathrm{\δ\ρ}}_{k_P}^j+v_k^j$

In the positioning calculation, utilize following formula according to the rough coordinates

of user terminal:

$\left\{\begin{array}{c}{X}_k={X_k}^0+{\mathrm{\δX}}_k\\ Y_k={Y_k}^0+{\mathrm{\δY}}_k\\ Z_k={Z_k}^0+{\mathrm{\δZ}}_k\end{array}\right.---\left(3\right)$

(2) formula is carried out 1 rank Taylor series expansion, obtains its linearization form:

$v_k^j=l_k^j{\mathrm{\δX}}_k+m_k^j{\mathrm{\δY}}_k+n_k^j{\mathrm{\δZ}}_k$

(4)

$-b_k+{\mathrm{\ρ}}_k^j-{\tilde{R}}_k^j+{\mathrm{c\δt}}^j-{\mathrm{\δ\ρ}}_{k_n}^j-{\mathrm{\δ\ρ}}_{k_P}^j$

In the formula,

For rough coordinates arrives satellite S _jDirection cosine:

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

is the distance of rough coordinates to satellite Sj:

${\tilde{R}}_k^j={[{(X^j-{X_k}^0)}^2+{(Y^j-Y_k^0)}^2+{(Z^j-{Z_k}^0)}^2]}^{1/2}---\left(6\right)$

Can calculate satellite S by navigation message _jIn the coordinate and the clock correction of signal x time, can calculate ionosphere and troposphere time delay by correlation formula.

Calculate and

and the known terms in the observation equation (4) is represented have with according to rough coordinates:

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

In the formula,

is:

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

Write formula (7) as matrix form, had:

V＝AΔX-L (9)

In the formula, Δ X is the undetermined parameter vector:

ΔX＝[δX _k?δY _k?δZ _k?b _k] ^T (10)

A is the matrix of coefficients of unknown parameter:

$A=\left[\begin{array}{cccc}{l}_k^1& m_k^1& n_k^1& -1\\ l_k^2& m_k^2& n_k^2& -1\\ ...& ...& ...& ...\\ l_k^n& m_k^n& n_k^n& -1\end{array}\right]---\left(11\right)$

L is the constant term vector:

$L={\left[\begin{array}{cccc}{L}_k^1& L_k^2& \·\·\·& L_k^n\end{array}\right]}^T---\left(12\right)$

V is the correction vector:

$V={\left[\begin{array}{cccc}{v}_k^1& v_k^2& \·\·\·& v_k^n\end{array}\right]}^T---\left(13\right)$

Doppler range rate measurement constraint: at t _kConstantly, user terminal records satellite S _j(j=1,2 ..., n) with respect to the speed v of user terminal _Rel, have:

v _rel＝v _j-v _u (14)

In the formula, v _uBe v _jBe respectively the speed of user and satellite.Can from navigation message, obtain satellite S _jPosition coordinates (X at the signal x time ^j, Y ^j, Z ^j) and speed v _j, the coordinate of user terminal is (X _k, Y _k, Z _k), satellite S then _jUnit vector e to this point _uFor:

$e_u=(\frac{X_k-X^j}{r_u},\frac{Y_k-Y^j}{r_u},\frac{Z_k-Z^j}{r_u})---\left(15\right)$

Here, $r_u=\sqrt{{(X_k-X^j)}^2+{(Y_k-{Y^j}_{})}^2+{(Z_k-Z^j)}^2}.$

Satellite S _jSpeed unit vector e _jFor:

$e_j=\frac{v_j}{\left|v_j\right|}=(\frac{v_{\mathrm{jx}}}{r_j},\frac{v_{\mathrm{jy}}}{r_j},\frac{v_{\mathrm{jz}}}{r_j})---\left(16\right)$

Here, $r_j=\sqrt{{v_{\mathrm{Jx}}}^2+{v_{\mathrm{Jy}}}^2+{v_{\mathrm{Jz}}}^2}.$

For stationary user, v _u=0, the actual measurement speed v _RelBe satellite velocities v _jThe projection components that makes progress to the user side at satellite is if accurately recorded v _Rel, then the user is constrained on satellite S _jBe summit, pseudorange

On the cone face for bus.As shown in Figure 1.

Unit vector e _uWith e _jAngle theta satisfy:

$e_u\·e_j=\frac{v_{\mathrm{rel}}}{v_j}---\left(17\right)$

Following formula is the Doppler range rate measurement equation of constraint that user terminal satisfies.Formula (7) obtains system of equations with formula (17) simultaneous, utilizes least square method to solve unknown parameter vector X, obtains the point to be located coordinate.Further rectangular space coordinate can be converted into the earth longitude and latitude and the geodetic height of user terminal.

For portable terminal, speed is the position change in the unit interval, utilizes double positioning result can obtain the speed initial value, in formula (17), and v _RelUse v _Rel+ v _uReplace obtaining the Doppler range rate measurement equation of constraint that portable terminal satisfies.Iterative computation can obtain the coordinate of portable terminal, and then obtains the earth longitude and latitude and the geodetic height at terminal.

Claims (6)

1. combine the localization method of Doppler range rate measurement in the satellite navigation, it is characterized in that, comprise step:

A) at least 2 Navsats, descending modulation one road navigation signal respectively;

B) user terminal receives every road navigation signal that Navsat is descending, measures the pseudorange of every Navsat respectively;

C) simultaneously, user terminal measurement is with respect to the doppler velocity of every Navsat;

D) user terminal utilizes b), c) observation pseudorange and the Doppler range rate measurement information of step gained every Navsat, the realization navigator fix.

2. the localization method of combination Doppler range rate measurement as claimed in claim 1 is characterized in that, said a) in navigation signal, comprise the ranging code and the numeric data code of carrier wave.

3. the localization method of combination Doppler range rate measurement as claimed in claim 1 is characterized in that, said d) the middle user terminal navigator fix of realizing is to the equation group:

$v_k^j=l_k^j\mathrm{\δ}{X}_k+m_k^j\mathrm{\δ}{Y}_k+n_k^j{\mathrm{\δZ}}_k-b_k-L_k^j$

$e_u\·e_j=\frac{v_{\mathrm{rel}}}{v_j}$

Utilize least square method to solve unknown parameter vector Δ X, wherein Δ X=[δ X _kδ Y _kδ Z _kb _k] ^T, obtain the user coordinates coordinate through iteration repeatedly, further convert rectangular space coordinate into the earth longitude and latitude and the geodetic height of user terminal again;

Be the constant term of observational error equation, e _uWith e _jBe unit vector, v _RelBe actual measurement speed, v _jBe satellite velocities.

4. the localization method of combination Doppler range rate measurement as claimed in claim 3 is characterized in that, the fixed point coordinate of said user terminal is constrained on satellite S _jBe summit, pseudorange

On the cone face for bus.

5. like the localization method of claim 1,3 or 4 described combination Doppler range rate measurements, it is characterized in that said user terminal is fixed terminal or portable terminal.

6. the localization method of combination Doppler range rate measurement as claimed in claim 5 is characterized in that, said fixed terminal is the fixed satellite receiving equipment; Portable terminal is vehicle-mounted, boat-carrying or hand-held receiving equipment.

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