WO2004040327A1

WO2004040327A1 - System for locaton and operation management of mobile vehicle using phase difference of arrival

Info

Publication number: WO2004040327A1
Application number: PCT/KR2002/002487
Authority: WO
Inventors: Rak Kyo Jeong; Yong Ki Yoon; Eun Ho Lee; Byeong Song Lee
Original assignee: Korea Railroad Research Institute
Priority date: 2002-10-30
Filing date: 2002-12-30
Publication date: 2004-05-13
Also published as: EP1563314A1; EP1563314A4; KR20040037730A; KR100483801B1

Abstract

Disclosed is a system for location of a moving vehicle running along a specific route using phase difference of arrival, comprising: a vehicle radio set mounted on the moving vehicle and adapted to send out a specific radio signal of the moving vehicle; a pluriality of wayside radio sets installed at certain intervals along the route and adapted to recevie the radio signal from the vehicle radio set; a station radio set adapted to receive the radio signal of the moving vehicle and indentification information of two corresponding ones of the plurality of wayside radio sets from the two corresponding wayside radio sets located at both sides in such a manner as to be opposite to each other with respect to a running spot which the moving vehicle is passing, and a position tracking section adapted to recevie the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets from the station radio set through a wired or radio communication network, and search a route database having data previously stored therein to calculate produce positioninformation of the moving vehicle from the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets using a phase difference between the two corresponding wayside radio sets with respect to the moving vehicle.

Description

SYSTEM FOR LOCATION AND OPERATION MANAGEMENT OF MOBILE VEHICLE USING PHASE DIFFERENCE OF ARRIVAL

Technical Field

The present invention relates to a system for tracking a near position of a moving vehicle. Specifically, the invention relates to a system for location and operation management of a moving vehicle using phase difference of arrival, which includes wayside radio sets ( RSs) installed on the ground in such a manner as to be spaced apart from each other at certain intervals, a vehicle radio set (VRS) installed in a moving vehicle and a station radio set (SRS) installed at a control station so as to locate the moving vehicle using a phase difference between a signal transmitted from the moving vehicle and a reference signal of the wayside radio sets, thereby .tracking the position of a train more accurately when applied to railroad vehicles.

Background Art

Although there are various location techniques currently being used, they provide relatively low position accuracy because they take into consideration all of the accuracy of location, and the size, consumption power and cost of a mobile station. In case of railroad that requires safety and reliability, however, the most important factor is the location accuracy rather than the size, consumption power and cost of the mobile station. Especially, for an unmanned operation system such as lightweight electric railway, the position of each railroad vehicle should be accurately grasped in order to organically control railroad vehicles to efficiently operate them.

Conventional location techniques include Global Positioning System (GSP), Time of Arrival (TOA) using propagation delay time between a fixed station on the ground and a mobile station, Time Difference of Arrival (TDOA) using time difference of arrival of a radio wave, transmitted from a mobile station, at base stations, Angle of Arrival (AOA) using an angle at which a radio wave transmitted from a mobile station arrives at a fixed station, and a method of using intensity of a radio wave transmitted to a fixed station from a mobile station.

The GPS is applicable to a system having a wider movement range because it can track the position of a wireless caller with a reception-dedicated terminal anywhere there is no obstacle. However, such a GPS can hardly be applied to a system like lightweight electric railway that runs downtown or underground. Also, it is difficult to apply the method using the intensity of a radio wave received by the fixed station and AOA to the lightweight electric railway because of many obstacles and underground sections. Thus, TOA and TDOA are currently used. Even in case of TOA and TDOA, however, it is difficult to synchronize time of each fixed station, resulting in generation of error.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a system for location and operation management of a moving vehicle using phase difference of arrival, which tracks the position of a moving vehicle that has transmitted a position signal based on a previously constructed route database using phase differences between radio stations installed along the route and the moving vehicle running along the route and performs operation management of the moving vehicle accordingly. To accomplish the object of the present invention, there is provided a system for location of a moving vehicle running along a specific route using phase difference of arrival, comprising: a vehicle radio set mounted on the moving vehicle and adapted to send out a specific radio signal of the moving vehicle; a plurality of wayside radio sets installed at certain intervals along the route and adapted to receive the radio signal from the vehicle radio set; a station radio set adapted to receive the radio signal of the moving vehicle and identification information of two corresponding ones of the plurality of wayside radio sets from the two corresponding wayside radio sets located at both sides in such a manner as to be opposite to each other with respect to a running spot which the moving vehicle is passing; and a position tracking section adapted to receive the radio signal of the moving vehicle and the identification information^' of the two corresponding wayside radio sets from the station radio set through a wired or radio communication network, and search a route database having data previously stored therein to calculate produce position information of the moving vehicle from the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets using a phase difference between the two corresponding wayside radio sets with respect to the moving vehicle. To accomplish the object of the present invention, there is also provided a system for tracking the position of a moving vehicle running along a specific route and managing the operation of the moving vehicle using phase difference of arrival, comprising: a vehicle radio set mounted on the moving vehicle and adapted to send out a specific radio signal of the moving vehicle; a plurality of wayside radio sets installed at certain intervals along the route and adapted to receive the radio signal from the vehicle radio set; a station radio set adapted to receive the radio signal of the moving vehicle and identification information of two corresponding ones of the plurality of wayside radio sets from the two corresponding wayside radio sets located at both sides in such a manner as to be opposite to each other with respect to a running spot which the moving vehicle is passing; a position tracking section adapted to receive the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets from the station radio set through a wired or radio communication network, and search a route database having data previously stored therein to calculate produce position information of the moving vehicle from the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets using a phase difference between the two corresponding wayside radio sets with respect to the moving vehicle; and an operation management section adapted to receive the calculated position information of the moving vehicle from the position tracking section to update an operation database having data previously stored therein and transmit a control command signal for controlling the operation of the moving vehicle to the station radio set.

Brief Description of the Drawings

Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing the entire configuration of a moving vehicle location system using phase difference of arrival according to the present invention;

FIG. 2 is a flow chart showing the operation process of the moving vehicle location system according to the present invention;

FIG. 3 is a block diagram showing the inner configuration of the position tracking unit shown in FIG. 1 ;

FIG. 4 is a conceptual diagram for explaining a method of estimating the position of an actual moving vehicle using a lineal distance obtained by using phase difference of arrival and a route database;

FIG. 5 is a diagrammatic view for explaining a method of determining the position of a train in a straight section adjacent to RS 4;

FIG. 6 is a diagram for explaining a method of estimating an actual distance when the train is located in a curved section; FIG. 7 is a flow chart showing a procedure of estimating the actual distance in FIG. 6; and

FIG. 8 is a conceptual diagram showing phase difference of arrival between WRS 4 and NRSs 2 and 3 shown in FIG. 1.

Best Mode for Carrying Out the Invention

The present invention will now be described in detail in connection with preferred embodiments with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing the entire configuration of a moving vehicle location system using phase difference of arrival according to the present invention.

Referring to FIG. 1, the moving vehicle location system using phase difference of arrival of the invention includes vehicle radio sets VRS1 3 and NRS 2 2 that are mounted on a moving vehicle and functions to send out a specific radio signal of the moving vehicle; wayside radio sets (WRS) 1, 4 and 5 that are installed at certain intervals along a route and serve to receive the radio signal from the NRS1 3 and NRS2 2 or to transmit a control command signal to the moving vehicle; a station radio set (SRS) 6 that acts to receive the radio signal of the moving vehicle and identification information of two corresponding ones of the wayside radio sets from the two corresponding wayside radio sets located at both sides in such a manner as to be opposite to each other with respect to a running spot the moving vehicle is passing; and a position tracking unit 8 that functions to receive the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets from the station radio sets (SRS) 6 through a radio communication network 7 and to search a route database 9 having data previously stored therein to calculate position information of the moving vehicle from the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets using a phase difference between the two corresponding wayside radio sets with respect to the moving vehicle

Also, a system for location and operation management of the moving vehicle using phase difference of arrival of the invention includes vehicle radio sets VRS1 3 and NRS 2 2 that are mounted on a moving vehicle and functions to send out a specific radio signal of the moving vehicle; wayside radio sets (WRS) 1, 4 and 5 that are installed at certain intervals along a route and serve to receive the radio signal from the NRS 1 3 and NRS2 2 or to transmit a control command signal to the moving vehicle; a station radio set (SRS) 6 that acts to receive the radio signal of the moving vehicle and identification information of two corresponding ones of the wayside radio sets from the two corresponding wayside radio sets located at both sides in such a manner as to be opposite to each other with respect to a running spot the moving vehicle is passing; a position tracking unit 8 that functions to receive the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets from the station radio sets (SRS) 6 through a radio communication network 7 and to search a route database 9 having data previously stored therein to calculate position information of the moving vehicle from the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets using a phase difference between the two corresponding wayside radio sets with respect to the moving vehicle; and an operation management unit 11 that serves to receive the calculated position information of the moving vehicle from the position tracking unit 8 to update an operation database 10 having data previously stored therein and transmit a control command signal for controlling the operation of the moving vehicle to the station radio set 6.

Here, the communication network may include TDMA, CDMA, FDMA networks and the like. In addition, the communication network is not limited to radio mobile communication networks, but may be applied to wired communication networks and Internet network. In order to carry out normal communication even when one of the vehicle radio sets 3 and 2 attached to the moving vehicle is out of order, the vehicle radio sets are respectively disposed set at the front and rear of the moving vehicle.

FIG. 2 is a flow chart showing the operation process of the moving vehicle location system according to the present invention.

When the NRS1 3 or VRS2 2 attached to the moving vehicle sends out a radio wave signal (SI), it is determined whether or not WRS 1 or 4 is placed adjacent to the SRS 6 (S2). If it is determined at step S2 that the WRS 1 or 4 is not placed adjacent to the SRS 6, the program proceeds to step S3 at which the VRSl 3 or VRS2 2 transmits the radio signal to the SRS 6 through the WRS adjacent to the VRSl 3 or VRS2 2 and the step S2 is performed repeatedly. That is, the WRS 1 or 4 located on the ground (at a side of a railroad track) receive the radio signal from the VRSl 3 or VRS2 2.

If, on the other hand, it is determined at step S2 that the WRS 1 or 4 is placed adjacent to the SRS 6, the program proceeds to step S4 where the WRS 1 or 4 transmits the received radio signal to the SRS 6. Subsequently, at step S5, the lineal distance between the WRS and VRS is measured using phase difference of arrival with respect to the radio signal received by the SRS 6, and then the program proceeds to step S6 where the accurate position of the VRS is determined from the measured value using the route database. Then, at step S7, a control command signal is sent to the moving vehicle (that is, a train) using the positions of other trains and information of the operation database.

FIG. 3 is a block diagram showing the inner configuration of the position tracking unit shown in FIG. 1. As shown in FIG. 3, the position tracking unit 8 includes a low-noise amplifier 102 for amplifying a signal received through an antenna 101 from the SRS 6, the first filter 103, a frequency down converter 104, the second filter 105, a phase controller 106, a reference signal generator 107, a phase comparator 108, a phase angle calculator 109, a lineal distance calculator 110, a route database inquiry unit 111 and an actual position calculator 112.

The radio signal received through the antenna 101 is supplied to the low- noise amplifier 102 which amplifies the received radio signal to an appropriate level, and then supplies the amplified radio signal to the first filter 103 which filters the amplified signal to select a signal of desired waveform. Then, The filtered signal is supplied to the frequency down converter 104 which converts a signal having an input frequency of hundreds MHz or GHz into a signal of about 1.5MHz through several processing steps. The aim of converting the frequency of an input signal into 1.5MHz or so is to make the propagation distance per cycle of the signal be similar to the distance (200m) between the two WRSs 1 and 4 located at both sides of the moving vehicle. If the propagation distance per cycle is much shorter than the distance between the two WRSs 1 and 4, even when a phase is measured, the location of the moving vehicle cannot be carried out because many phases exists within a section. On the other hand, when the propagation distance per cycle is longer than the distance between the two WRSs 1 and 4, phase variation per unit distance becomes small, resulting in an increase in error. Accordingly, it is preferable that the propagation distance per cycle is identical to the distance between the two WRSs 1 and 4. However, since it is impossible to accurately control the positions of the WRSs 1 and 4 in the actual situation, frequency is preferably adjusted such that the propagation distance per cycle is slightly longer than the distance between the two WRSs 1 and 4.

The down-converted signal of a low frequency is supplied to the second filter 105 which filters it for application to the phase comparator 108 which, in turn, compares a phase of the filtered signal with that of a reference signal having the same frequency, that is generated by the reference signal generator 107 and phase-controlled by the phase controller 106. Then, the phase angle calculator 109 calculates a phase of the input signal according to the compared result.

Here, since the phase of the reference signal can be controlled, these values can be adjusted when the moving vehicle passes a reference position (WRS) without specific synchronization control. Resultantly, the lineal distance calculator 110 calculates the lineal distances between the WRSs 1 and 4 and a point at which the moving vehicle is currently located using the phase difference between the input signal and the reference signal. Then, The route database inquiry unit 111 inquires the radius of curvature of the route and gradient information stored in the route database 9 and the lineal distances. The actual position calculator 112 obtains the actual position of the moving vehicle using the inquired information. According to the aforementioned method, the positions of all moving vehicles on the route are grasped and the next operation instruction is transferred to each of the moving vehicles using operation information stored in the moving vehicle operation database.

Because a railroad track is constructed to have both straight and curved courses, the estimation of the actual distance by which the moving vehicle travels from the reference point requires approximation. In an unmanned operation system such as lightweight electric railway, control of trains, especially, control of the interval between trains is based on difference positions according to the railroad track. Accordingly, the position of the moving vehicle is obtained by calculating the lineal and curved distances between the moving vehicle and the reference point. The linear distance between the WRSl 4 and VRSl 3 is measured using the phase difference of arrival.

Accordingly, it is necessary that the measured lineal distance be converted into the actual driving distance. A method for converting the lineal distance into the actual driving distance is classified into a method that constructs a database for a phase difference previously obtained using the lineal distance measured by using a phase difference and the route database, and the distance according to the phase difference and then performs conversion of data stored in the constructed database, and a method that divides the route into sections according to the characteristics of the route in advance, determines a section corresponding to the measured lineal distance and obtains the driving distance using a relation expression based on the determined section.

The former method has a problem in that since if requires a massive database, its processing speed also is relatively slow. Accordingly, the present invention employs the latter method that previously divides the route into sections according to the characteristics of the route to locate a train based on the divided sections.

FIG. 4 is a conceptual diagram for explaining a method of estimating the position of an actual moving vehicle using a lineal distance obtained by using phase difference of arrival and a route database.

First, using WRS 4 as a reference wayside radio set, the route is appropriately divided into straight and curved sections. If the route is divided into too many sections, the quantity of database becomes massive. Thus, the division interval of the route should be set within a range satisfying a desired error. In the case where a curved section has different radiuses of curvature, the route is divided into appropriate sections according to the radiuses of curvature.

FIG. 5 is a diagrammatic view for explaining a method of determining the position of a train in a straight section adjacent to WRS 4.

As shown in FIG. 5, the method of locating a train in a straight section adjacent to the WRS 4 obtains the actual driving distance of the train through the

Pythagorean theorem using the lineal distance Lc between the WRS 4 and a track and the lineal distance LI between the WRS 4 and VRSl 3, as shown in the following expression 1.

[Expression 1]

{L}_{VRS1 }-R00T {{L1 }^Λ{2}-{{L}_{C}}^Λ{2}}

In the case where the moving vehicle, that is, VRS2 2 is located at a curved section, the method of estimating an actual distance of the moving vehicle is shown in FIG. 6.

FIG. 7 is a flow chart showing a procedure of estimating the actual distance in FIG. 6; and

First, the lineal distance B between WRSl 4 and VRS2 2 is measured using phase difference of arrival (Sl l), and the section where the VRS2 2 is located is found using the measured lineal distance B (S12). Then, the actual driving distance is estimated using the relationship between the phase difference and driving distance in that section. Using the center of the radius of curvature with respect to the WRSl 4 and the curved section, and information on a start point of the curved section S6 from the database, the angle θl of the triangle, composed of the distance A between the WRS 4 and the start point of the section S6, the distance C between the WRS 4 and the center of the radius of curvature and the radius of curvature R, is obtained using the following expression 2 (SI 3).

[Expression 2]

A² = C² + R² - 2CRCOSΘI

Then, the angle Θ2 of the triangle, composed of the distance B between the WRSl 4 and VRS2 2, the distance C between the WRSl 4 and the center of the radius of curvature and the radius of curvature R, is obtained through the following expression 3 (SI 4).

[Expression 3]

_B ² = ² + R² - 2CRCOSΘ2

The above expressions can be re- written in terms of θl and Θ2 as follows:

[Expression 4] 01 = -- COS^~ c² + R² - - A²

2CR + R²

Θ2 -- = COS^~ , c² - - B²

2CR

Accordingly, the angle θ made by the start point of the section S6 and the VRS2 2 is obtained by the following expression 5 (SI 5).

[Expression 5]

,_, C² + R² - B² ,_„_, C² + R² - A² _ _ __, B² - A¹

Θ = θ\ - Θ2 = COS" ^— — COS^'1 ^— — = COS^'

2CR 2CR 2CR

As can be seen from the expression 5, the angle θ between the start point of the section S6 and the VRS2 2 can be obtained when the distance A between the WRSl 4 and the start point of the section S6, the distance B between the WRSl 4 and the VRS2 2, the distance C between the WRSl 4 and the center of the radius of curvature and the radius of curvature R are known. Here, A, C and R are values determined from the route database and B is a value measured using phase difference of arrival. The curved distance d that the moving vehicle has actually moved can be obtained by substituting the angle θ into the following expression 6 (SI 6).

[Expression 6]

d = -^-2πR 360

Accordingly, the final position of the train corresponds to the distance to the start point of the section S6 plus the distance d (S17). FIG. 8 is a conceptual diagram showing phase difference of arrival between WRS 4 and VRSs 2 and 3 shown in FIG. 1. As shown in FIG. 8, when high frequency signals transmitted from the VRSl 3 and VRS2 2 are converted into signals having a frequency range of about 1.5MHz and the converted signals are compared with the reference signal having the same frequency as provided by the WRSl 4, the VRSl 3 and VRS2 2 show phase differences of about 90° and 180°, respectively. These phase differences vary with the position of the train. For example, when the distance between the WRSs and the train is 200m and intermediate frequency is 1.5MHz, phase difference of approximately 1.8° per unit distance is generated.

Industrial Applicability

As described above, the present invention can grasp the current position of a moving vehicle running on a specific route using phase differences of arrival between WRSs installed around the route and VRSs attached to the moving vehicle without using the conventional GPS.

The SRS of the present invention can calculate position coordinates of the moving vehicle that has transmitted a position signal from a route database having data previously stored therein using signals of the vehicle received from the multiple WRSs through a radio communication network and the phase differences between the vehicle and the WRSs adjacent to the vehicle.

In case of railroad, generally, a vehicle running route is constructed of a combination of both a straight section and curved sections having various radiuses of curvature. Thus, in order to grasp the actual accurate position of the vehicle, the distances between the VRS and neighboring two WRSs is divided into multiple sections based on the straight and curved sections, the section in which the vehicle is located is found using the lineal distance obtained from the phase differences between the WRSs and VRS, and the accurate position of the vehicle is calculated using the relationship between the phase differences and the distance in that section. The measurement of accurate position of the moving vehicle according to the present invention is a key technique required for constructing an unmanned railroad operation system. With this technique, intervals between trains running on the same track can be optimally controlled. Accordingly, railway transport efficiency can be increased and operation interval can be more safely maintained, thereby improving reliability in railroad service.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.

Claims

What Is Claimed Is:

1. A system for location of a moving vehicle running along a specific route using phase difference of arrival, comprising: a vehicle radio set mounted on the moving vehicle and adapted to send out a specific radio signal of the moving vehicle; a plurality of wayside radio sets installed at certain intervals along the route and adapted to receive the radio signal from the vehicle radio set; a station radio set adapted to receive the radio signal of the moving vehicle and identification information of two corresponding ones of the plurality of wayside radio sets from the two corresponding wayside radio sets located at both sides in such a manner as to be opposite to each other with respect to a running spot which the moving vehicle is passing; and a position tracking section adapted to receive the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets from the station radio set through a wired or radio communication network, and search a route database having data previously stored therein to calculate produce position information of the moving vehicle from the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets using a phase difference between the two corresponding wayside radio sets with respect to the moving vehicle.

2. The system as claimed in claim 1, wherein the vehicle radio set includes a plurality of vehicle radio sets mounted on the moving vehicle in such a manner as to be spaced apart from each other.

3. The system as claimed in claim 1, wherein the position tracking section comprises: an amplification and filtering part adapted to amplify and filter a signal received from the station radio set through an antenna; a frequency down-converter adapted to down-convert the frequency of the filtered signal such that the propagation distance per cycle of the signal corresponds to the distance between the wayside radio sets located at both sides of the moving vehicle; a reference signal generator adapted to generate a reference signal used for phase comparison with the moving vehicle; a phase comparator adapted to compare the phase of the output signal of the frequency down- converter with that of the reference signal; and a position calculator adapted to calculate the lineal distances between the moving vehicle and the wayside radio sets located at both sides of the moving vehicle from the output of the phase comparator and calculate the actual position of the moving vehicle with reference to the route database.

4. The system as claimed in claim 3, wherein frequency down-converter uses a phase difference in which the propagation distance per cycle of the signal is identical to or slightly longer than the distance between the wayside radio sets located at both sides of the moving vehicle.

5. The system as claimed in claim 3, wherein the position calculator divides the route into sections according to the characteristics of the route in advance, determines a section corresponding to the measured lineal distance, estimates the actual driving distance of the moving vehicle within the determined section, and adds the distance to the section to the actual driving distance to calculate the final position of the moving vehicle.

6. A system for tracking the position of a moving vehicle running along a specific route and managing the operation of the moving vehicle using phase difference of arrival, comprising: a vehicle radio set mounted on the moving vehicle and adapted to send out a specific radio signal of the moving vehicle; a plurality of wayside radio sets installed at certain intervals along the route and adapted to receive the radio signal from the vehicle radio set; a station radio set adapted to receive the radio signal of the moving vehicle and identification information of two corresponding ones of the plurality of wayside radio sets from the two corresponding wayside radio sets located at both sides in such a manner as to be opposite to each other with respect to a running spot which the moving vehicle is passing; a position tracking section adapted to receive the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets from the station radio set through a wired or radio communication network, and search a route database having data previously stored therein to calculate produce position information of the moving vehicle from the radio signal of the moving vehicle and the identification information of the two corresponding wayside radio sets using a phase difference between the two corresponding wayside radio sets with respect to the moving vehicle; and an operation management section adapted to receive the calculated position information of the moving vehicle from the position tracking section to update an operation database having data previously stored therein and transmit a control command signal for controlling the operation of the moving vehicle to the station radio set.