CN1694567A - Method for positioning mobile terminal by single base station - Google Patents

Abstract

A single base station positioning method relates to a location method relates to a location method for mobile terminals in the cellular network, which uses single location base station to search, position and track to mobile terminals of cellular networks. A location base station tests the pilot signal time delay of a cellular base station serving the tracked target and searches for the entering channel of the target mobile terminal, estimates the arrived time delay to construct an elliptical equation taking the cellular base station and location base station as the focal points with the help of the above two time delay differential value to get the orientation angle of the target arriving at the base station to determine two crossing points, which can be the position of the searched target, one point is abandoned based on the action distance of the cellular service base station, the rest one is the determined target position.

Description

A kind of method of positioning mobile terminal by single base station

Technical field

The present invention relates to a kind of wireless location method, be particularly useful for the Cellular Networks portable terminal is positioned.

Background technology

At present, the Cellular Networks mobile terminal positioning system is divided into based on mobile position estimation and location Network Based two big classes, location based on travelling carriage utilizes the signal estimation of cellular network base stations to go out the position of oneself, commonly used have GPS, an AGPS (GPS Aided) etc., and its shortcoming is will existing portable terminal be transformed; The calculated signals that based on network location utilizes travelling carriage to transmit goes out the position of travelling carriage, but generally will transform network, location algorithm commonly used comprises TOA/TDOA (Time ofArrival/Time Difference of Arrival), AOA (Angle of Arrival), AOA/RTD (Angle of Arrival/Round Trip Delay), EOTD (EnhancedObserved Time difference), Cell-ID, SOA localization methods such as (Strength of Arrival).

With the immediate prior art of the application, see document (Performance of A TDOA-AOA HybridMobile Location System.N.J.Thomas, D.G.Cruickshank and D.I.Laurenson.3G Mobile Communication Technologies, what No.477IEE2001 March 2001.) adopt is the TDOA location technology that is independent of the Cellular Networks system, this location technology is in actual environment for use, need to arrange the locating base station more than three, this many base stations navigation system need arrange that locating base station is too much, make locating base station arrange overlong time, must do bigger change to terminal and network, cause cost to increase; Positioning accuracy is subjected to the geometric layout of locating base station, locating base station geographical position, the influence of factors such as the non-horizontal surface between locating base station, make that TDOA location technology precision is lower, many locating base station system is too much in operation last time, and the position derivation algorithm is complicated, and real-time is low; Locating base station requires and Cellular Networks is set up synchronously, can not separate use.

Summary of the invention

In order to solve the above-mentioned defective that exists in the existing location technology, a kind of new localization method of this positioning system using, this navigation system only need be provided with a locating base station LMU in cellular mobile network, solve in the prior art in the navigation system of many base stations locating base station and arranged overlong time, defectives such as positioning accuracy is not high, algorithm is complicated, real-time is low, and one-time investment is excessive.

The technical solution adopted for the present invention to solve the technical problems is: a locating base station LMU is set in cellular mobile network; Locating base station can adopt the triantennary structure, obtains the geographical location information of the cellular network base stations BS that serves tracked target, calculates the access direction of arrival of signal angle (the relative angle AOA that is portable terminal and locating base station is θ) of portable terminal; Locating base station is measured the time delay τ that arrives locating base station from cdma cellular net base station BS pilot transmitted signal _B, measure the time delay τ that arrives locating base station from portable terminal _M, the time delay difference of determining both is τ=τ _M-τ _BThe structure elliptic equation is found the solution travelling carriage relative positioning base station geographical coordinate, thereby is obtained the two-dimensional position of portable terminal relative positioning base station; Covering radius according to cellular network base stations; Geographical coordinate position in the cellular network base stations covering radius is a mobile terminal locations.

The present invention adopts location, single base station in the Cellular Networks system, overcome the above-mentioned defective of many base stations navigation system in the prior art, manufacturing cost is cheaper, positioning accuracy is higher, the positioning time of system is few, and is real-time, easy to use, the quick location that can be widely used in travelling carriage in the Cellular Networks is particularly useful for vehicle-carried mobile base station navigation system.

Description of drawings

Figure 1 shows that single base station navigation system structure

Figure 2 shows that the AOA estimation of locating base station to portable terminal

Figure 3 shows that the ellipse figure that difference obtains according to the time of advent

Figure 4 shows that the AOA and time of advent difference joint estimate figure

Figure 5 shows that and determine portable terminal final position figure

Embodiment

As shown in Figure 1, when cellular network base stations is separated with locating base station, use single locating base station method to finish location to portable terminal, build single base station localizing environment, locating base station is placed in the targeted environment that needs localisation of mobile terminals, and the definite of this target position information can obtain according to the environment of an activation of target or from mobile terminal operator.Locating base station LMU adopts the triantennary structure in this system.At first search the portable terminal that needs the location, up to the pilot signal time delay that searches target information, obtain the cellular network base stations of serving tracked target; Obtain the geographical location information of cellular network base stations, determine the covering radius of cellular network base stations.As shown in Figure 2, the signal that utilizes MS (Mobile Station portable terminal) to send, adopt many antennas field intensity difference method to realize the Fast estimation of relative angle AOA, calculating portable terminal is θ with respect to the relative angle AOA of locating base station, with the locating base station is starting point, with θ is that angle is made straight line l, and the portable terminal that we will measure is just on this straight line l.

Locating base station is measured portable terminal and is inserted time of arrival (toa), calculates the time delay τ that arrives locating base station from cdma cellular net base station BS pilot transmitted signal _B, calculate from portable terminal and arrive locating base station time delay τ _M

The range equation that cdma cellular net base station BS arrives locating base station LMU is:

$\sqrt{{(x_L-x_B)}^2+{(y_L-y_B)}^2}={\mathrm{\τ}}_B\·C$ Formula 1

τ wherein _B=τ _E+ τ _BL, τ _EBe cdma cellular net base station BS.τ _BLArrive the signal propagation time of locating base station LMU from cdma cellular net base station BS for signal.

From cdma cellular net base station BS be through the range equation that mobile station MS arrives locating base station LMU:

$\sqrt{{(x-x_L)}^2+{(y-y_L)}^2}+\sqrt{{\left({x-x}_B\right)}^2+{\left({y-y}_B\right)}^2}={\mathrm{\τ}}_M\·C$ Formula 2

Wherein:

τ _B＝τ _E+τ _BML+τ _EM，

τ _EBe base station pilot time precision error.

τ _BMLBe the signal propagation time of signal from cdma cellular net base station BS process mobile station MS arrival locating base station LMU,

τ _EMBe mobile station MS sign indicating number structure time error, τ _EMVery little with respect to other error, can ignore.

After travelling carriage obtains the temporal information of cdma cellular net base station BS, determine corresponding code phase, so the temporal information of the signal that travelling carriage BS sends comprises: cdma cellular net base station BS pilot tone time precision error, arrive locating base station LMU time delay, sign indicating number structure time error τ through mobile station MS from cdma cellular net base station BS _EM

After formula 1 and formula 2 carried out difference, the time corresponding delay difference was τ=τ _M-τ _BCan eliminate the error τ of pilot tone time precision _E, this error range is in 1 μ s, and root-mean-square error is 86.6 meters, is the main error of single base station navigation system.Therefore, use single base station navigation system after, can eliminate most of error of system, make its location more accurate.

According to the time difference of two paths of signals, determine elliptic equation

Structure is measured equation:

$\sqrt{{\left({x-x}_L\right)}^2+{\left({y-y}_L\right)}^2}+\sqrt{{\left({x-x}_B\right)}^2+{\left({y-y}_B\right)}^2}$

$=\mathrm{\τ}\·C+\sqrt{{(x_L-x_B)}^2+{(y_L-y_B)}^2}$

X wherein, y: the travelling carriage geographical coordinate, wait to ask;

x _L, y _L: the locating base station geographical coordinate is given value;

x _B, y _B: the geographical coordinate of cellular network base stations is given value.

Above-mentioned equation is described as an ellipse with locating base station and cellular network base stations formation.

Find the solution above-mentioned equation, obtain travelling carriage geographical coordinate x, y, promptly be two intersection points of above-mentioned ellipse and ray l, according to the covering radius of cellular cell, give up an outer intersection point of covering radius of cellular cell, an intersection point in the cellular cell covering radius is the position of measured portable terminal, thereby obtain the two-dimensional position of portable terminal relative positioning base station, realize location travelling carriage.

Figure 3 shows that the ellipse that the time of advent, difference obtained, wherein CDMA BS is expressed as the cellular network base stations of portable terminal service, and LMU represents locating base station, and MS represents portable terminal.

Fig. 4 differs from the relative angle AOA and the time of advent joint estimate figure, wherein CDMA BS is expressed as the cellular network base stations position of portable terminal service, LMU represents the locating base station position, find the solution above-mentioned equation obtain figure cathetus and oval two intersection points (MS-A, MS-B) that intersect be the time of advent difference and AOA unite the position of the portable terminal of trying to achieve.

Figure 5 shows that the definite figure in portable terminal final position, wherein CDMA BS in the left side is expressed as the cellular network base stations position of portable terminal service, LMU represents the locating base station position, the dotted line hexagon is the cell boarder of BS, what the MS-A in the cellular cell bounds represented is determined mobile terminal locations, and the MS-B outside the cellular cell bounds is the intersection point of giving up.

The target location is repeatedly located, utilize said method to obtain one group and separate, it is carried out statistical average, assembly average just is the position of the final portable terminal of determining.

In the Cellular Networks system, use single base station positioning method of the present invention, position fixing process and base station are set up simple and convenient, locating base station can be separated use with cellular network base stations, can realize portable terminal is located fast and accurately, can be widely used in the location of portable terminal in the Cellular Networks, be particularly useful for the vehicle-carried mobile navigation system that to carry out fast target, conveniently to locate.

Though the foregoing description is described at the cdma cellular net, the present invention not only is applicable to the cdma cellular network, the terminal in all wireless networks is positioned this method all be suitable for.

Claims (4)

1, a kind of single base station positioning method is characterized in that, this localization method comprises the steps:

(1) locating base station (LMU) is set in cellular network;

(2) search the portable terminal that needs the location, obtain the geographical location information of cellular network base stations (BS), calculate the access direction of arrival of signal angle of portable terminal;

(3) locating base station is measured the time delay τ that arrives locating base station from cellular network base stations pilot transmitted signal _B, measure the time delay τ that arrives locating base station from portable terminal _M, calculate both time delay difference component τ=τ _M-τ _B

(4) find the solution the geographical coordinate of travelling carriage with respect to locating base station;

(5) give up an outer geographical coordinate of cellular network base stations covering radius, the geographical coordinate position in the cellular network base stations covering radius is defined as the portable terminal coordinate position.

2, a kind of single base station positioning method according to claim 1 is characterized in that, described locating base station adopts the triantennary structure.

3, a kind of single base station positioning method according to claim 1, it is characterized in that, calculate the method that inserts the direction of arrival of signal angle in the step (2) and comprise the signal that utilizes portable terminal to send, adopt many antennas field intensity difference method to realize the Fast estimation of deflection.

4, a kind of single base station positioning method according to claim 1, it is characterized in that, the described travelling carriage of finding the solution with respect to the method for the geographical coordinate of locating base station is: utilize the pilot signal time delay of cellular network base stations and difference component that portable terminal access channel signal time postpones as setting up the parameter of measuring equation

Structure is measured equation: $\sqrt{{(x-x_L)}^2+{(y-y_L)}^2}+\sqrt{{(x-x_B)}^2+{(y-y_B)}^2}$

$=\mathrm{\τ}\·C+\sqrt{{(x_L-x_B)}^2+{(y_L-y_B)}^2}$

Wherein, x _L, y _L: locating base station geographical coordinate, x _B, y _B: the cellular network base stations geographical coordinate, find the solution unknown number x, y is the travelling carriage geographical coordinate.

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