CN1185897C - Method for estimating position of mobile station and its device - Google Patents

Abstract

The present invention discloses a method for estimating the position of a mobile station. The method acquires the relevant statistical information of TOA corresponding to a main base station and TDOA corresponding to other base stations by the corresponding measurement to the TOA of the main base station and the TDOA corresponding to the other base stations of the main base station. According to the position information of the base stations and the construction operation matrices of statistical information of the relevant TOA and TDOA, the weighted linear least square is twice used to estimate the position of the mobile station, and finally, the estimate value of the final position is selected by making use of the difference of the minimum distances. The method integrates the advantages of the TDOA method and the TOA method to a certain extent, and the positional estimation accuracy and the GDOP performance of the mobile station are totally increased. Simultaneously, the positional estimation process of the method does not need iterative solution; the operation amount is small, and the efficiency is high. Simultaneously, the present invention also provides the positional estimation device of the mobile station, and the device comprises a TOA generator, a TDOA generator, an information database and a position estimator.

Description

A kind of method of estimation of location of mobile station and device

Technical field

The present invention relates to the wireless location technology in the mobile communication system, relate in particular to mobile station positioning method and device in the mobile communication system.

Background technology

In mobile communication system, utilize temporal information that travelling carriage is positioned usually, this mobile station positioning method based on temporal information generally is divided into two big classes: a class is to utilize TOA (Time OfArrival: individual signals the time of advent) to position, and a class is to utilize TDOA (TimeDifference Of Arrival: two signal arrival time differences) position.When travelling carriage is positioned, must there be a base station (in most cases only having) and travelling carriage to keep being connected, with regard to signal measurement, the TOA of the base station that is connected with the travelling carriage maintenance measures than being easier to and realizes, because the TDOA of a certain relatively reference base station of different base station measures also and realizes easily, make to keep the TOA of the base station that connects to measure with travelling carriage and the TDOA of relative this base station measures realization easily.When utilizing these measurement data to carry out location estimation, following scheme is arranged generally, the one, directly use the TDOA algorithm to carry out location estimation, the 2nd, utilize dominant base TOA to convert different TDOA to corresponding TOA, utilize the TOA algorithm to carry out location estimation then.

Generally speaking, directly utilize TDOA to carry out the location estimation of travelling carriage, although the time of advent of signal, difference energy TDOA can eliminate to a certain degree systematic error and part NLOS (non-visual range: error Non_Line of Sight), the TDOA of different base station measures also and realizes easily, but the performance of the location estimation of travelling carriage is relatively more responsive to the relative position between travelling carriage and the base station, it is the GDOP (geometric dilution of precision: poor-performing Geomtry Dilution of Precision) of the type method, particularly when travelling carriage when the base station, the location estimation performance of this method obviously descends.And singly deposit when utilizing TOA to carry out location estimation, although GDOP better performances, lower to travelling carriage and base station location sensitiveness, but travelling carriage is directly measured difficult the realization to the TOA of different base station, simultaneously to the NLOS error unrestraint effect of system's intrinsic error and signal.In a word, existing method is lower to the precision of the location estimation of travelling carriage.

Summary of the invention

The objective of the invention is to, the method and the device of the higher estimating position of mobile station of a kind of precision, efficient is provided.

For achieving the above object, the method for estimation of location of mobile station provided by the invention comprises:

(1) chooses a base station keeping being connected with travelling carriage as dominant base, other base station of mobile position estimation is carried out in definite participation, initiate the time of arrival (toa) of travelling carriage and dominant base and differ from corresponding measurement the time of advent with other signal of base station of relative dominant base, described measurement comprises: the measurement of the RTT of dominant base (two-way time), the measurement of the transmitting-receiving time difference of travelling carriage, and other base station signal with respect to the dominant base signal to travelling carriage the time of advent difference measurements and other base station signal with respect to difference measurements launch time of dominant base signal;

(2), generate the corresponding propagation time of signal from the dominant base to the travelling carriage and corresponding signal propagation time difference from other base station and dominant base to travelling carriage according to the measured value of above-mentioned base station and travelling carriage;

(3) obtain above-mentioned base station base station coordinates and with the corresponding propagation time of signal from the dominant base to the travelling carriage and corresponding signal relevant statistical information from other base station and dominant base to the propagation time difference of travelling carriage;

(4) utilize base station coordinates that above-mentioned steps (3) provides and, determine the final position estimated value of travelling carriage about the propagation time and the signal of the correspondence location estimation of carrying out travelling carriage from other base station and dominant base to the statistical information of the propagation time difference of travelling carriage of corresponding signal from the dominant base to the travelling carriage.

Above-mentioned steps (4) further comprises the steps:

(31) determine that the fundamental equation that utilizes time of arrival (toa) and signal arrival time difference to carry out the location of mobile station estimation is as follows: ${(x-x_1)}^2+{(y-y_1)}^2={\left(r_1\right)}^2$

${(\sqrt{{(x-x_i)}^2+(y-y_i^2)}-\sqrt{{(x-x_i)}^2+(y-y_i^2)})}^2=r_{i1}^2$

In the formula: i=2 .m, m＞=3, wherein to equal 1 base station be dominant base under the travelling carriage to i, r ₁=c * τ ₁, τ ₁For the signal of dominant base arrives propagation time of travelling carriage, r _I1=c * τ _I1, τ _I1Be the propagation time difference of the signal arrival travelling carriage of i the relative dominant base in base station, c is the speed (light velocity) that signal is propagated.x _i, y _iIt is the geometric position coordinate of i base station.X, y are the geometric position coordinate of travelling carriage to be estimated.

(32) according to the fundamental equation of above-mentioned steps (31), use the weighted linear least square method to estimate the rough position of travelling carriage, obtain separating according to a preliminary estimate of location of mobile station;

(33) the location estimation value of the travelling carriage that above-mentioned steps (32) is obtained reuses the weighted linear least square method and is optimized, and reduces the correlation influence between the described location estimation value;

(34) the optimization position estimated value of the travelling carriage that obtains according to above-mentioned steps (33) is determined the location estimation value that travelling carriage is final.

Use the weighted linear least square method to estimate that the rough position of travelling carriage further comprises in the wherein said step (32):

(41) fundamental equation to above-mentioned steps (21) carries out conversion, obtains following formula:

r ₁-d ₁＝0

$r_{21}^2+x_1^2-x_2^2+y_1^2-y_2^2-2(x_1-x_2)x-2(y_1-y_2)y+2r_{21}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1=0$

$r_{31}^2+x_1^2-x_3^2+y_1^2-y_3^2-2(x_1-x_3)x-2(y_1-y_3)y+2r_{31}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1=0$

…

$r_{m1}^2+x_1^2-x_m^2+y_1^2-y_m^2-2(x_1-x_m)x-2(y_1-y_m)y+2r_{m1}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1=0;$

In the formula: it is dominant base: r that i=2 .m, and m＞=3, i equal 1 base station ₁=c * τ ₁, τ ₁For the signal of dominant base arrives propagation time of travelling carriage, c is the speed that signal is propagated; r _I1=c * τ _I1, τ _I1It is the propagation time difference that i the relative dominant base signal of base station signal arrives travelling carriage; x _i, y ₁It is the geometric position coordinate of i base station; ${\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1=\sqrt{{\left({x-x}_1\right)}^2+{\left({y-y}_1\right)}^2};$ X, y are the geometric position coordinate of travelling carriage to be estimated;

(42) structural matrix h, Ga, Ksi are the form of following least square: Δ=h-GaZa with the formulae express in the above-mentioned steps (41);

In the formula: Δ is residual error; Ksi is the weighting coefficient matrix when carrying out least-squares estimation,

Ksi＝E(ΔΔ ^T)＝c ²BQB

Wherein: B=diag{1,2 (r ₂₁+ r ₁), 2 (r ₃₁+ r ₁) ..., 2 (r _M1+ r ₁), diag represents diagonal matrix, Q is propagation time and signal the covariance matrix from two different base stations to the error of the propagation time difference of same travelling carriage of signal to travelling carriage, expression signal credibility;

$h={\left[\begin{array}{c}{r}_1\\ r_{21}^2+x_1^2-x_2^2+{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^2-y_2^2\\ <figure-callout\; id="1"\; label="...\; r\; m"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">.</figure-callout>..& \\ r_m^{}{1}_2^{}+x_1^2-x_m^2+y_1^2-y_m^2\end{array}\right]}_{,}$ $\mathrm{Ga}=\left[\begin{array}{ccc}0& 0& 0\\ 2(x_1-x_2)& 2(y_1-y_2)& -2r_{21}\\ ...& ...& ...\\ 2(x_1-x_m)& 2(y_1-y_m)& -2{\mathrm{<figure-callout\; id="1"\; label="r\; m"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">r</figure-callout>}}_m\end{array}\right]$

$\mathrm{Za}={\left[\begin{array}{c}x\\ y\\ {\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1\end{array}\right]}_{;}$

(43) calculate Za according to described matrix h, Ga, Ksi, obtain separating according to a preliminary estimate of location of mobile station.

In described step (43), calculate Za as follows:

Za＝(Ga ^TKsi ^-1Ga) ^-1Ga ^TKsi ^-1h。

Described step (33) further comprises:

(61) structural matrix h ', Ga ', Ksi ', determine following least squares formalism:

Δ′＝h′-Ga′Za′

Δ in the formula ' be residual error, Ksi '=E (Δ ' Δ ^T), and, Ksi '=B ' (Ga ^TKsi ^-1Ga) ^-1B ', wherein $B^{\&prime;}=\mathrm{diag}\{2(x^0-x_1),2(y^0-y_1),{2\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^0\};$

${\mathrm{Ga}}^{\&prime;}=\left[\begin{array}{cc}1& 0\\ 0& 1\\ 1& 1\end{array}\right]$ $h^{\&prime;}=\left[\begin{array}{c}{(Z_{a,1}-x_1)}^2\\ {(Z_{a,2}-y_1)}^2\\ Z_{a,3}^2\end{array}\right]$ ${\mathrm{Za}}^{\&prime;}={\left[\begin{array}{c}{(x-x_1)}^2\\ {(y-y_1)}^2\end{array}\right]}_{;}$

(62) according to described matrix h ', Ga ', Ksi ' calculating Za ', separate the exact position that obtains location of mobile station.

In described step (62), calculate Za ' as follows:

Za′＝(Ga′? ^TKsi′ ^-1Ga′) ^-1Ga′ ^TKsi′ ^-1h′。

Described step (34) further may further comprise the steps:

(91) according to following method construct matrix ${\mathrm{Zp}}^{\&prime;}={\left[\begin{array}{c}x\\ y\end{array}\right]}_{:}$ ${\mathrm{Zp}}^{\&prime;}=\&PlusMinus;\sqrt{{\mathrm{Za}}^{\&prime;}}+{\left[\begin{array}{c}{x}_1\\ {\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">y</figure-callout>}}_1\end{array}\right]}_{,}$ Obtaining four groups of final positions of travelling carriage separates;

(92), during separate four groups of final positions of the travelling carriage from above-mentioned steps (91), select the final position estimated value of separating of respective distances difference minimum as travelling carriage according to the range difference of separating according to a preliminary estimate of location of mobile station.

The present invention also provides a kind of estimation unit of location of mobile station simultaneously, comprising:

Signal propagation time and signal propagation time bad student grow up to be a useful person: the signal propagation time and the propagation time difference corresponding measured value of other base station signal that participates in mobile position estimation with respect to dominant base signal arrival travelling carriage that are used to receive dominant base, described measured value comprises: the measurement of round trip time value of dominant base signal, the transmitting-receiving time difference measurements value of travelling carriage, and other base station signal arrives the difference measurements value and the corresponding signal transmission time difference measurements value time of advent of travelling carriage with respect to the dominant base signal, and above-mentioned measured value is converted to dominant base signal propagation time and other base station signal arrive travelling carriage with respect to the dominant base signal propagation time difference as follows:

The dominant base signal arrive travelling carriage the propagation time=(the transmitting-receiving time difference measurements value of base station signal measurement of round trip time value-travelling carriage)/2;

Other base station signal arrives the propagation time difference=corresponding signal arrival time difference measured value-corresponding signal transmission time difference measurements value of travelling carriage with respect to the dominant base signal;

Information database: the geometric position and relevant statistical information that are used to store the base station that participates in mobile position estimation;

Position estimator: be used for described geometric position of the base station that signal propagation time and the signal propagation time difference and the described information database of output provide that utilizes signal propagation time and signal propagation time bad student to grow up to be a useful person and relevant statistical information, carry out the location estimation of travelling carriage, determine the final position estimated value of travelling carriage.

Described position estimator comprises:

Memory: be used to receive and comprise that the dominant base signal arrives the statistical information of propagation time difference, base station coordinates, signal propagation time and the propagation time difference of travelling carriage with respect to the dominant base signal to the signal propagation time value of travelling carriage, other base station signal, carry out location of mobile station required data when estimating, and the intermediate data and the final data that produce during the storing mobile station location estimation;

Processor: be used for estimating required data, utilize least square method to carry out the estimation of location of mobile station according to the location of mobile station that carries out that obtains from described memory.

Because the present invention can fully utilize dominant base time of arrival (toa) and one group of other base station signal arrive travelling carriage with respect to the dominant base signal propagation time difference, utilizing least square method to carry out location of mobile station estimates, combine the advantage of time of arrival (toa) and signal arrival time difference method to a certain extent, the position estimation accuracy and the GDOP performance of travelling carriage all are improved, are suitable for nearly all occasion that needs mobile position estimation; The present invention simultaneously carries out in the position estimation procedure need not iterative, and operand is little, and the location estimation required time is also less, therefore adopts the present invention that the Location Request quantity of the system handles in the same time period is obviously increased.

Description of drawings

Fig. 1 is that the method for the invention is carried out the geometrical principle figure that location of mobile station is estimated;

Fig. 2 is the embodiment flow chart of the method for the invention;

Fig. 3 is the specific embodiment flow chart of step 4 among Fig. 2;

Fig. 4 is the embodiment block diagram of device of the present invention;

Fig. 5 is the embodiment block diagram of the described position estimator of Fig. 4;

Fig. 6 is the simulation performance figure of the present invention under the T1P1 channel model.

Embodiment

The present invention is described in further detail below in conjunction with drawings and Examples.

The method and apparatus that invention proposes is applicable to that the base station more than 3 or 3 participates in travelling carriage is carried out location estimation.Fig. 1 has provided the propagation time and other base station signal that utilize the dominant base signal to arrive travelling carriage and has carried out the geometrical principle figure that location of mobile station is estimated with respect to the propagation time difference that the dominant base signal arrives travelling carriage.Among Fig. 1, different circles and hyp intersection point are the position of travelling carriage, and when there are error in signal propagation time and signal propagation time difference, curve will not meet at a bit, but approximate region.

Fig. 2 is the embodiment flow chart of the method for the invention.Implement the present invention according to Fig. 2, choose a base station keeping being connected with travelling carriage as dominant base in step 1, other base station of mobile position estimation is carried out in definite participation, initiate the time of arrival (toa) of travelling carriage and dominant base and differ from corresponding measurement the time of advent with other signal of base station of relative dominant base, described measurement comprises: the RTT of dominant base measures, the transmitting-receiving time difference measurements of travelling carriage, and other base station is measured and the signal transmission time difference measurements with respect to the signal arrival time difference of dominant base.

In step 2,, generate the dominant base signal according to following method and arrive the propagation time of travelling carriage and other base station signal arrives travelling carriage with respect to the dominant base signal propagation time difference according to the measured value of above-mentioned base station and travelling carriage:

The dominant base signal arrive travelling carriage the propagation time=(the transmitting-receiving time difference measurements value of the measurement of round trip time value-travelling carriage of dominant base signal)/2;

Other base station signal arrives the propagation time difference=corresponding signal arrival time difference measured value-signal transmission time difference measurements value of travelling carriage with respect to the dominant base signal.

In step 3, obtain all coordinates that participate in base station that travelling carriage is positioned and with the relevant statistical information of the corresponding signal propagation time difference in the corresponding signal propagation time of dominant base and other base station;

In step 4, utilize base station coordinates that above-mentioned steps 3 provides and about the statistical information of signal propagation time and signal propagation time difference, carry out the location estimation of travelling carriage according to following step, and then the final position estimated value of definite travelling carriage, detailed process is with reference to figure 3.

Flow process described in Fig. 3 mainly comprises three partial contents, and first is that step 41 arrives step 43, adopts the weighted linear least square method to obtain separating according to a preliminary estimate of location of mobile station.

At first determine that in step 41 fundamental equation that utilizes signal propagation time and signal propagation time difference to carry out the location of mobile station estimation is as follows:

${\left({x-x}_1\right)}^2+{\left({y-y}_1\right)}^2={\left(r_1\right)}^2$

${(\sqrt{{\left({x-x}_1\right)}^2+(y-y_i^2)}-\sqrt{{\left({x-x}_1\right)}^2+(y-{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^2)})}^2={\mathrm{<figure-callout\; id="1"\; label="r\; i"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">r</figure-callout>}}_i^1---\left(1\right)$

In the formula: i=2 .m, m=3, wherein to equal 1 base station be dominant base under the travelling carriage to i, r ₁=c * τ ₁, τ ₁Be the propagation time of dominant base signal arrival travelling carriage, r _I1=c * τ _I1, τ _I1Be the propagation time difference that i the relative dominant base signal of base station signal arrives travelling carriage, c is the speed (light velocity) that signal is propagated, x _i, y _iBe the geometric position coordinate of i base station, x, y are the geometric position coordinate of travelling carriage to be estimated.

In step 42, at first the fundamental equation to above-mentioned steps 41 carries out conversion, obtains following formula:

r ₁-d ₁＝0

$r_{21}^2+x_1^2-x_2^2+{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^2-y_2^2-2(x_1-x_2)x-2(y_1-y_2)y+2r_{21}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1=0$

$r_{31}^2+x_1^2-x_3^2+{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^2-{\mathrm{<figure-callout\; id="3"\; label="y"\; filenames="C0113646100202.png"\; state="\{\{state\}\}">y</figure-callout>}}_3^2-2(x_1-x_3)x-2(y_1-y_3)y+2r_{31}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1=0$

…

$r_{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">m</figure-callout>}1}^2+x_1^2-x_m^2+{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^2-y_m^2-2(x_1-x_m)x-2(y_1-y_m)y+2r_{m1}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1=0-----\left(2\right);$

In the formula: it is dominant base that i=2 .m, and m=3, i equal 1 base station; r ₁=c * τ ₁, τ ₁Be the propagation time of dominant base signal arrival travelling carriage, c is the speed that signal is propagated; r _I1=c * τ _I1, τ _I1It is the propagation time difference that i the relative dominant base signal of base station signal arrives travelling carriage; x _i, y _iIt is the geometric position coordinate of i base station; ${\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1=\sqrt{{(x-x_1)}^2+{(y-y_1)}^2};$ X, y are the geometric position coordinate of travelling carriage to be estimated;

Structural matrix h, Ga, Ksi then are expressed as above-mentioned formula (2) form of following least square:

Δ＝h-GaZa (3)；

The purpose of least square is to make ‖ Δ ‖ ²Minimum.

In the formula: Δ is residual error; Ksi is the weighting coefficient matrix when carrying out least-squares estimation,

Ksi＝E(ΔΔ ^T)＝c ²BQB (4)

Wherein: B=diag{1,2 (r ₂₁+ r ₁), 2 (r ₃₁+ r ₁) ..., 2 (r _M1+ r ₁), diag represents diagonal matrix, Q is propagation time and signal the covariance matrix from two different base stations to the error of the propagation time difference of same travelling carriage of signal to travelling carriage, expression signal credibility.Described covariance matrix Q generally is configured to diagonal matrix, and element is that signal is to the propagation time of travelling carriage and the variance of the propagation time difference error of signal from two different base stations to same travelling carriage on the diagonal.

$h={\left[\begin{array}{c}{r}_1\\ r_{21}^2+x_1^2-x_2^2+{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^2-y_2^2\\ ...\\ {\mathrm{<figure-callout\; id="1"\; label="r\; m"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">r</figure-callout>}}_m^1+x_1^2-x_m^2+{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^2-y_m^2\end{array}\right]}_{,}$ $\mathrm{Ga}=\left[\begin{array}{ccc}0& 0& 0\\ 2(x_1-x_2)& 2(y_1-y_2)& -2r_{21}\\ ...& ...& ...\\ 2(x_1-x_m)& 2(y_1-y_m)& -2{\mathrm{<figure-callout\; id="1"\; label="r\; m"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">r</figure-callout>}}_m\end{array}\right]$

$\mathrm{Za}={\left[\begin{array}{c}\mathrm{<figure-callout\; id="1"\; label="x\; y\; d"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">x</figure-callout>}& \\ y\\ d_{}{}_1\end{array}\right]}_{;}$

In step 43, calculate Za according to described matrix h, Ga, Ksi.Suppose that x, y, d1 are separate, utilize the weighted linear least square to find the solution Za,

Za＝(Ga ^TKsi ^-1Ga) ^-1Ga ^TKsi ^-1h (5)

And then obtain separating according to a preliminary estimate of location of mobile station.

Because the existence of time of arrival (toa) and signal arrival time difference measure error in the reality, and system might provide redundant metrical information, makes that the location of mobile station data precision that obtains from formula (51) is not high.Therefore the second portion of the flow process described in Fig. 3 is that step 44 arrives step 45, adopts the weighted linear least square method once more, reduces the influence of the correlation between x, y, the d1.

In step 44, structural matrix h ', Ga ', Ksi ', determine following least squares formalism:

Δ′＝h′-Ga′Za′ (6)

The purpose of least square is to make ‖ Δ ‖ ²Minimum.

Δ in the formula ' be residual error, Ksi '=E (Δ ' Δ ' ^T), and,

Ksi '=B ' (Ga ^TKsi ^-1Ga) ^-1B ' (7) wherein $B^{\&prime;}=\mathrm{diag}\{2(x^0-x_1),2(y^0-y_1),{2\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="C0113646100231.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^0\};$

${\mathrm{Ga}}^{\&prime;}=\left[\begin{array}{cc}1& 0\\ 0& 1\\ 1& 1\end{array}\right]$ $h^{\&prime;}=\left[\begin{array}{c}{(Z_{a,1}-x_1)}^2\\ {(Z_{a,2}-y_1)}^2\\ Z_{a,3}^2\end{array}\right]$ ${\mathrm{Za}}^{\&prime;}={\left[\begin{array}{c}{(x-x_1)}^2\\ {(y-y_1)}^2\end{array}\right]}_{;}$

X in the described reality ⁰, y ⁰Can use the Z that tries to achieve among the Za _{A, 1}, Z _{A, 2}Come approximate solution, r ₁ ⁰Can use Z _{A, 3}Come approximate.

In step 45, according to described matrix h ', Ga ', Ksi ' calculating Za ', just utilize x, y, contact between d1 and the covariance matrix of Za are found the solution with least-squares estimation ${\mathrm{Za}}^{\&prime;}={\left[\begin{array}{c}{(x-x_1)}^2\\ {(y-y_1)}^2\end{array}\right]}_{.}$ Concrete computing formula is as follows:

Za′＝(Ga′ ^TKsi′ ^-1Ga′) ^-1Ga′ ^TKsi′ ^-1h′ (8)

And then separate the exact position that obtains location of mobile station.

The third part of the flow process described in Fig. 3 is a step 46 to step 47, from separating that above-mentioned formula (8) obtains, picks out the final position estimated value of travelling carriage.In step 46, structural matrix ${\mathrm{Zp}}^{\&prime;}={\left[\begin{array}{c}x\\ y\end{array}\right]}_{,}$ Calculate Zp ' according to following method then:

${\mathrm{Zp}}^{\&prime;}=\&PlusMinus;\sqrt{{\mathrm{Za}}^{\&prime;}}+\left[\begin{array}{c}{x}_1\\ y_1\end{array}\right]---\left(9\right)$

And then separate the final position that obtains travelling carriage;

Because the form of separating of the final location of mobile station that formula (9) obtains has four, and wherein have only one to be the location estimation value that needs, so, the strategy that present embodiment adopts is: according to the range difference of separating according to a preliminary estimate of location of mobile station, from separate the final position of above-mentioned travelling carriage, select the final position estimated value of separating of respective distances difference minimum as travelling carriage.

Fig. 4 is the embodiment block diagram of device of the present invention.The estimation unit 204 of the location of mobile station that Fig. 4 describes comprises:

Signal propagation time and signal propagation time bad student grow up to be a useful person 201: the signal propagation time and the propagation time difference corresponding measured value of other signal of base station that participates in mobile position estimation with respect to dominant base signal arrival travelling carriage that are used to receive dominant base, described measured value comprises: the signal measurement of round trip time value of dominant base, the transmitting-receiving time difference measurements value of travelling carriage, and other base station signal is converted to the dominant base signal as follows with above-mentioned measured value and arrives the propagation time value of travelling carriage and other base station signal arrives travelling carriage with respect to the dominant base signal propagation time difference with respect to the signal arrival time difference measured value and the signal transmission time difference measurements value of dominant base signal:

The dominant base signal arrive travelling carriage the propagation time=(the signal transmitting and receiving time difference measurements value of dominant base signal measurement of round trip time value-travelling carriage)/2;

Other base station signal arrives the propagation time difference=corresponding signal arrival time difference measured value-signal transmission time difference measurements value of travelling carriage with respect to the dominant base signal;

Information database 202: the geometric position and relevant statistical information that are used to store the base station that participates in mobile position estimation;

Position estimator 203: be used for described geometric position of the base station that signal propagation time and the signal propagation time difference and the described information database of output provide that utilizes signal propagation time and signal propagation time bad student to grow up to be a useful person and relevant statistical information, carry out the location estimation of travelling carriage, determine the final position estimated value of travelling carriage.

At first signal propagation time and signal propagation time bad student grow up to be a useful person and 201 choose a base station keeping being connected with travelling carriage as dominant base, the corresponding measurement of other signal of base station propagation time difference of initiation and dominant base signal propagation time and relative dominant base; Signal propagation time and the signal propagation time bad student 201 relevant measured values according to base station and travelling carriage of growing up to be a useful person generate corresponding signal propagation time and signal propagation time difference then; Information database 202 provides the relevant base station coordinate, and the relevant statistical information of signal propagation time and signal propagation time difference, adopt dominant base signal propagation time+a plurality of signal propagation time differences to carry out location estimation by position estimator 203, at last, position estimator 203 provides the location of mobile station estimated value.

Described position estimator 203 comprises:

Memory 301: the statistical information that is used to receive other signal of base station propagation time difference, base station coordinates, signal propagation time and the signal propagation time difference that comprise dominant base signal propagation time value, relative dominant base, carry out location of mobile station required data when estimating, and the intermediate data and the final data that produce during the storing mobile station location estimation;

Processor 302: be used for estimating required data, utilize least square method to carry out the estimation of location of mobile station according to the location of mobile station that carries out that obtains from described memory.

The concrete operation that location of mobile station is estimated be have processor 302 can according to formula (1) to the formula of formula (9) with require computing to obtain.Intermediate data that computing relates to and final data are stored in the memory 301.

Fig. 6 is the simulation performance figure of the present invention under the T1P1 channel model.What describe among the figure is the emulation of carrying out under T1P1 channel model UrbanA environment.The abscissa of Fig. 6 is a travelling carriage estimated distance error, and unit is m, the probability of ordinate for taking place.What (ordinates) a bit represent range error among the figure on the curve is less than the probability of certain value (abscissa).As seen from the figure, performance of the present invention is better than the location estimation performance of signal propagation time least square gradient descent method and signal propagation time difference Chen Shi algorithm.

Claims (11)

1, a kind of method of estimation of location of mobile station comprises:

(1) chooses a base station keeping being connected with travelling carriage as dominant base, other base station of mobile position estimation is carried out in definite participation, initiate the time of arrival (toa) of travelling carriage and dominant base and differ from corresponding measurement the time of advent with other signal of base station of relative dominant base, described measurement comprises: the measurement of the transmitting-receiving time difference of the measurement of the two-way time of dominant base signal, travelling carriage, and the measurement of other corresponding signal arrival time difference in base station and the measurement of other base station with respect to the signal transmission time difference of dominant base;

(2), generate the corresponding propagation time of signal from the dominant base to the travelling carriage and corresponding signal propagation time difference from other base station and dominant base to travelling carriage according to the measured value of above-mentioned base station and travelling carriage;

(3) obtain above-mentioned base station base station coordinates and with propagation time and signal the relevant statistical information from other base station and dominant base to the propagation time difference of travelling carriage of signal from the dominant base to the travelling carriage;

(4) utilize base station coordinates that above-mentioned steps (3) provides and, determine the final position estimated value of travelling carriage about the propagation time and the signal of the correspondence location estimation of carrying out travelling carriage from other base station and dominant base to the statistical information of the propagation time difference of travelling carriage of corresponding signal from the dominant base to the travelling carriage.

2, the method for estimation of location of mobile station according to claim 1 is characterized in that the implementation method of described step (2) is as follows:

Signal from the dominant base to the travelling carriage the propagation time=(the transmitting-receiving time difference measurements value of measured value-travelling carriage of dominant base signal two-way time)/2;

Signal propagation time difference=corresponding signal arrival time difference measured value-other base station from other base station and dominant base to travelling carriage is with respect to the signal transmission time difference measurements value of dominant base.

3, the method for estimation of location of mobile station according to claim 1 is characterized in that: described step (4) further comprises the steps:

(31) determine that the fundamental equation that utilizes time of arrival (toa) and signal arrival time difference to carry out the location of mobile station estimation is as follows:

${(x-x_1)}^2+{(y-y_1)}^2={\left(r_1\right)}^2$

${(\sqrt{{(x-x_i)}^2+(y-y_i^2)}-\sqrt{{(x-x_i)}^2+(y-y_1^2)})}^2=r_{i1}^2$

In the formula: i=2 .m, m＞=3, wherein to equal 1 base station be dominant base under the travelling carriage to i, r ₁=c * τ ₁, τ ₁Be the propagation time of dominant base signal to travelling carriage, r _Il=c * τ _Il, τ _I1Be the propagation time difference of the signal arrival travelling carriage of i the relative dominant base in base station, c is the speed light velocity that signal is propagated, x _i, y _iBe the geometric position coordinate of i base station, x, y are the geometric position coordinate of travelling carriage to be estimated.

(32) according to the fundamental equation of above-mentioned steps (31), use the weighted linear least square method to estimate the rough position of travelling carriage, obtain separating according to a preliminary estimate of location of mobile station;

(33) the location estimation value of the travelling carriage that above-mentioned steps (32) is obtained reuses the weighted linear least square method and is optimized, and reduces the correlation influence between the described location estimation value;

(34) the optimization position estimated value of the travelling carriage that obtains according to above-mentioned steps (33) is determined the location estimation value that travelling carriage is final.

4, the method for estimation of location of mobile station according to claim 3 is characterized in that: use the weighted linear least square method to estimate that the rough position of travelling carriage further comprises in the described step (32):

(41) fundamental equation to above-mentioned steps (31) carries out conversion, obtains following formula:

r ₁-d ₁＝0

$r_{21}^2+x_1^2-x_2^2+y_1^2-y_2^2-2(x_1-x_2)x-2(y_1-y_2)y+{2r}_{21}{d}_1=0$

$r_{31}^2+x_1^2-x_3^2+y_1^2-y_3^2-2(x_1-x_3)x-2(y_1-y_3)y+{2r}_{31}{d}_1=0$

...

$r_{m1}^2+x_1^2-x_m^2+y_1^2-y_m^2-2(x_1-x_m)x-2(y_1-y_m)y+{2r}_{m1}{d}_1=0;$

In the formula: it is dominant base that i=2 .m, and m＞-3, i equal 1 base station; r ₁=c * τ ₁, τ ₁Be the propagation time of signal from the dominant base to the travelling carriage, c is the speed that signal is propagated; r _I1=c * τ _I1, τ _I1It is the propagation time difference that i the relative dominant base signal of base station signal arrives travelling carriage; x _i, y _iIt is the geometric position coordinate of i base station; $d_1=\sqrt{{(x-x_1)}^2+{(y-y_1)}^2};$ X, y are the geometric position coordinate of travelling carriage to be estimated;

(42) structural matrix h, Ga, Ksi are the form of following least square: Δ=h-GaZa with the formulae express in the above-mentioned steps (41);

In the formula: Δ is residual error; Ksi is the weighting coefficient matrix when carrying out least-squares estimation,

Ksi＝E(ΔΔ ^T)＝c ²BQB

Wherein: B=diag{1,2 (r ₂₁+ r ₁), 2 (r ₃₁+ r ₁) ..., 2 (r _M1+ r ₁), diag represents diagonal matrix, Q is propagation time and signal the covariance matrix from two different base stations to the error of the propagation time difference of same travelling carriage of signal to travelling carriage, expression signal credibility;

$h=\left[\begin{array}{c}{r}_1\\ r_{21}^2+x_1^2-x_2^2+y_1^2-y_2^2\\ \&CenterDot;\&CenterDot;\&CenterDot;\\ r_{m1}^2+x_1^2-x_m^2+y_1^2-y_m^2\end{array}\right],$

$\mathrm{Ca}=\left[\begin{array}{ccc}0& 0& 1\\ 2(x_1-x_2)& 2(y_1-y_2)& -{2r}_{21}\\ \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;\\ 2(x_1-x_m)& 2(y_1-y_m)& -{2r}_{m1}\end{array}\right]$

$\mathrm{Za}=\left[\begin{array}{c}x\\ y\\ d_1\end{array}\right],$

(43) calculate Za according to described matrix h, Ga, Ksi, obtain separating according to a preliminary estimate of location of mobile station.

5, the method for estimation of location of mobile station according to claim 4 is characterized in that: calculate Za as follows in described step (43):

Za＝(Ga ^TKsi ^-1Ga) ^-1Ga ^TKsi ^-1h。

6, the method for estimation of location of mobile station according to claim 4 is characterized in that: described step (33) further comprises:

(61) structural matrix h ', Ga ', Ksi ', determine following least squares formalism:

Δ′＝h′-Ga′Za′

Δ in the formula ' be residual error, Ksi '=E (Δ ' Δ ' ^T), and, Ksi '=B ' (Ga ^TKsi ^-1Ga) ^-1B ', wherein $B^{\&prime;}=\mathrm{diag}\{2(x^0-x_1),2(y^0-y_1),{2r}_1^0\};$

${\mathrm{Ca}}^{\&prime;}=\left[\begin{array}{cc}1& 0\\ 0& 1\\ 1& 1\end{array}\right]$ $h^{\&prime;}=\left[\begin{array}{c}{(Z_{a,1}-x_1)}^2\\ {(Z_{a,2}-y_1)}^2\\ Z_{a,3}^2\end{array}\right]$ ${\mathrm{Za}}^{\&prime;}=\left[\begin{array}{c}{(x-x_1)}^2\\ {(y-y_1)}^2\end{array}\right];$

(62) according to described matrix h ', Ga ', Ksi ' calculating Za ', separate the exact position that obtains location of mobile station.

7, the method for estimation of location of mobile station according to claim 6 is characterized in that: in described step (61), and x ⁰, y ⁰Can use the Z that tries to achieve among the Za _{A, 1}, Z _{A, 2}Come approximate solution, r ₁ ⁰Can use Z _{A, 3}Be similar to, described Za is four lines one column matrix, described Z _{A, 1}Be the element of first row, first row, described Z _{A, 2}It is the element of second row, first row.

8, the method for estimation of location of mobile station according to claim 6 is characterized in that: calculate Za ' in described step (62) as follows:

Za＝(Ga＇ ^TKsi＇ ^-1Ga＇) ^-1Ga＇ ^TKsi＇ ^-1h′。

9, the method for estimation of location of mobile station according to claim 6 is characterized in that: described step (34) further may further comprise the steps:

(91) according to following method construct matrix ${\mathrm{Zp}}^{\&prime;}=\left[\begin{array}{c}x\\ y\end{array}\right]:$ ${\mathrm{Zp}}^{\&prime;}=\&PlusMinus;\sqrt{{\mathrm{Za}}^{\&prime;}}+\left[\begin{array}{c}{x}_1\\ y_1\end{array}\right],$

Separate four groups of final positions that obtain travelling carriage;

(92), during separate four groups of final positions of the travelling carriage from above-mentioned steps (91), select the final position estimated value of separating of respective distances difference minimum as travelling carriage according to the range difference of separating according to a preliminary estimate of location of mobile station.

10, a kind of estimation unit of location of mobile station comprises:

Signal propagation time and signal propagation time bad student grow up to be a useful person: other base station that is used to receive the signal propagation time of dominant base and participate in mobile position estimation is with respect to the signal propagation time difference corresponding measured value of dominant base to travelling carriage, described measured value comprises: the measured value of the two-way time of dominant base, the measured value of the transmitting-receiving time difference of mobile station signal, and the measured value of other corresponding signal arrival time difference in base station and signal transmission time difference measurements value, it is poor with respect to the signal propagation time that dominant base arrives travelling carriage to propagation time and other base station of travelling carriage that above-mentioned measured value is converted to the dominant base signal as follows:

The signal of dominant base to travelling carriage the propagation time=(measured value of the transmitting-receiving time difference of measured value-mobile station signal of base station signal two-way time)/2;

Other base station relatively with dominant base to the signal propagation time of travelling carriage poor=the signal transmission time difference measurements value of the measured value of signal arrival time difference-accordingly accordingly;

Information database: the geometric position and relevant statistical information that are used to store the base station that participates in mobile position estimation;

Position estimator: be used for described geometric position of the base station that the signal propagation time of output and the value of signal propagation time difference and described information database provide that utilizes signal propagation time and signal propagation time bad student to grow up to be a useful person and relevant statistical information, carry out the location estimation of travelling carriage, determine the final position estimated value of travelling carriage.

11, the estimation unit of location of mobile station according to claim 1 is characterized in that: described position estimator comprises:

Memory: be used to receive and comprise that the dominant base signal arrives the statistical information of value, base station coordinates, signal propagation time and signal propagation time difference of the propagation time difference of travelling carriage with respect to the dominant base signal to the value in the propagation time of travelling carriage, other base station signal, carry out location of mobile station required data when estimating, and the intermediate data and the final data that produce during the storing mobile station location estimation.

Images