CN106143538A - A kind of train locating method based on LTE R utilizing double-movement platform - Google Patents

Abstract

The invention discloses an LTE-R-based train positioning method utilizing dual mobile stations, comprising the following steps: determining two communication base stations of the LTE-R communication system adjacent to the front and back of the service area where the train is located as the positioning service base station, by positioning The service base station sends downlink signals containing the positioning reference signal PRS to the train at the same time; the two vehicle-mounted mobile stations located at the front and rear of the train receive the signals respectively, and the vehicle-mounted data processing module calculates that the PRS signal of the positioning service base station reaches the two The time difference of a vehicle-mounted mobile station, and according to the time difference of arrival and the position coordinates of the positioning service base station, two reference signal arrival time difference unilateral hyperbolas are generated. The two unilateral hyperbolas intersect with the train travel curve at two points. The length fuses these two intersection points to finally get the train position. The invention improves the utilization rate of the existing communication system, reduces the positioning cost, utilizes the information of the railway train itself, and improves the positioning accuracy of the train.

Description

A LTE-R-based train positioning method using dual mobile stations

technical field

The invention belongs to the technical field of rail transit, and relates to a train positioning method, in particular to an LTE-R-based train positioning method using dual mobile stations.

Background technique

Existing train positioning methods mainly rely on traditional equipment such as track circuits, query transponders, odometers, and new equipment such as GPS and spread spectrum wireless positioning to complete. Among them, traditional equipment is expensive to use, poor in safety and maintainability, and can only provide point-type location information, and cannot achieve continuous positioning; although GPS can achieve continuous positioning of trains, its high precision and high reliability are not comparable to those of visible satellites. The number and geometric distribution are inseparable, and subject to the performance of satellite equipment, the above factors are not within the control of the railway operation department. Once the satellite fails and cannot be repaired immediately, the train operation will be greatly affected; spread spectrum radio positioning The device has the advantage of high positioning accuracy, but it needs to set up a dedicated spread spectrum base station, the positioning cost is high, and it is easily interfered by the complex wireless communication environment, thus affecting the positioning effect.

In recent years, some ideas of using railway dedicated communication system for train positioning have been put forward one after another. For example, the GSM-R (GSM for Railway, railway digital mobile communication system) base station positioning method deployed along the railway, and the train positioning method using the railway dedicated broadband mobile communication system LTE-R proposed later, all use communication base stations and vehicle-mounted The signal receiving and sending equipment realizes the wireless positioning of the train.

The new generation of railway dedicated communication system LTE-R has more technical advantages than the GSM-R system, specifically: high data rate, packet transmission, and reduced delay, and the positioning reference signal is specially designed in the positioning protocol, no need to design A special burst sequence is used as a positioning request, so it is more forward-looking to use the LTE-R system to realize train positioning.

However, the above-mentioned method of using the railway dedicated communication system for train positioning is not high in positioning accuracy. The random error introduced by a single receiver in the positioning process is relatively large, and the reliability and stability of the positioning system are poor. Therefore, it is necessary to comprehensively consider the operational performance. As well as the cost, a new train positioning method is provided to solve the above problems.

Contents of the invention

The present invention provides an LTE-R-based train positioning method using dual mobile stations, which mainly aims at the technical problem of low positioning accuracy of the existing railway communication system, improves the utilization rate of the existing communication system, reduces the positioning cost, and The purpose of making full use of the information of the railway train itself to improve the positioning accuracy of the train.

The present invention achieves the above object through the following technical solutions:

A method for positioning a train based on LTE-R utilizing dual mobile stations, specifically comprising the following steps:

S1: Determine the communication base station in the service area where the train is currently located, use the communication base stations of the two railway mobile communication system LTE-R adjacent to the communication base station as the positioning service base station, and obtain the position coordinates of these two positioning service base stations; The two positioning service base stations simultaneously send the downlink signal containing the positioning reference signal PRS to the train;

S2: Use the two vehicle-mounted mobile stations located at the front and rear of the train to receive the above-mentioned positioning signals, and calculate by the vehicle-mounted data processing module, the positioning reference signals PRS from the above-mentioned two positioning service base stations respectively arrive at the two vehicle-mounted mobile stations The time difference of the positioning reference signal arrival time difference, the on-board data processing module generates two reference signal arrival time difference unilateral hyperbolas according to the positioning reference signal arrival time difference and the location coordinates of the positioning service base station;

S3: The two unilateral hyperbolas of the arrival time difference intersect with the current travel curve of the train at two points, and the on-board data processing module performs positioning data fusion on the above two intersection points according to the length of the train, and finally obtains the position of the train.

Preferably, the positioning data fusion in the above step S3 specifically refers to performing fusion processing on the midpoint of the two intersection points; first, the above two intersection points are the positions of the front and rear of the vehicle obtained from the positioning of the base station. Then, according to the natural stretching length of the train at the moment, the midpoint position is moved along the traveling direction of the train and the opposite direction of the train respectively moving the distance of half the train length of the above-mentioned train length to obtain the front and rear of the train actual location coordinates.

Preferably, the positioning service base station is a distributed positioning base station.

Preferably, the vehicle-mounted mobile station refers to two mobile stations respectively arranged at the front and rear of the train, and each mobile station includes a set of signal sending and receiving equipment.

Preferably, the positioning reference signal PRS is a signal specially used for wireless positioning introduced in the protocol specification of the mobile communication system LTE-R, which can only be transmitted on the resource blocks allocated by LTE, and is applicable to the mobile communication system with a subcarrier spacing of 15kHz. In this case, it is transmitted on antenna port 6, and the positioning reference signal used for positioning is transmitted on the antenna port, which reduces the interference between the reference signal and the useful signal, and will not cause interference to other communication services in the LTE-R communication system .

The beneficial effects of the present invention are:

1. Use the dual-machine vehicle-mounted mobile station to receive the positioning signal of the base station, and solve the problem that the single receiver introduces a large random error in the positioning process and the reliability and stability of the positioning system are poor;

2, because the distance of the length of train i.e. the headstock and the tailstock is known, the present invention utilizes this characteristic, and the base station initial positioning data of the tailstock, the headstock that obtains gets the midpoint and carries out fusion processing, has improved positioning accuracy, It solves the problem of large error and inaccurate positioning of existing wireless positioning;

3. The present invention makes full use of the information of the railway train itself to improve the positioning accuracy of the train; and improves on the basis of the existing system, improves the utilization rate of the existing communication system, and reduces the cost of positioning transformation.

Description of drawings

Fig. 1 is the schematic flow diagram of the train positioning process based on LTE-R utilizing dual mobile stations in the present invention;

Fig. 2 is a schematic layout diagram of a base station based on LTE-R utilizing dual mobile stations in the present invention;

Fig. 3 is a schematic diagram of the positioning principle based on LTE-R utilizing dual mobile stations in the present invention;

FIG. 4 is a schematic diagram of positioning data fusion based on LTE-R using dual mobile stations in the present invention.

detailed description

The present invention and its effects will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figures 1, 2, and 3, a LTE-R-based train positioning method utilizing dual mobile stations specifically includes the following steps:

Step 1: Determine the communication base station in the service area where the train is currently located, use the communication base stations of the two railway mobile communication system LTE-R adjacent to the communication base station as the positioning service base station, and obtain the position coordinates of these two positioning service base stations; The two positioning service base stations simultaneously send the downlink signal containing the positioning reference signal PRS to the train;

As shown in Figure 2, firstly search the serving cell according to the general process of base station serving cell search, determine the current communication base station of the train——base station 2, and then determine the two adjacent communication base stations according to the position of communication base station 2 as positioning Serving base stations—base station 1 and base station 3, obtain the location coordinates of the two positioning service base stations; and base station 1 and base station 3 simultaneously send downlink signals containing positioning reference signal PRS to the train. Among them, the positioning reference signal PRS is a signal specially used for wireless positioning introduced by the mobile communication system LTE in its ninth edition protocol specification R9, which can only be transmitted on the resource blocks allocated by LTE, and is applicable to the case where the subcarrier spacing is 15kHz , transmitted on the antenna port 6, the positioning reference signal used for positioning is transmitted on the antenna port, which reduces the interference between the reference signal and other useful signals, and will not cause interference to other communication services in the LTE-R communication system .

Step 2: Utilize the two vehicle-mounted mobile stations placed at the front and rear of the train to receive the above-mentioned positioning signals respectively, the vehicle-mounted mobile station is the vehicle-mounted sending and receiving module, which contains a set of signal sending and receiving equipment; calculated by the vehicle-mounted data processing module It can be seen that the positioning reference signal PRS from the above two positioning service base stations respectively arrives at the two vehicle-mounted mobile stations, that is, the positioning reference signal arrival time difference, and the vehicle-mounted data processing module generates a Two reference signal arrival time difference unilateral hyperbola;

As shown in Figure 3, the two mobile stations located at the front and rear of the vehicle receive positioning signals at the same time, and the on-board data processing module calculates respectively the positioning reference signal PRS sent by base station 1 and base station 3 to reach the two signal receivers, namely the vehicle-mounted mobile station. The time differences d ₁₁ , d ₁₂ , d ₃₁ and d ₃₂ are combined with the position coordinates of base station 1 and base station 3 to obtain the one-sided hyperbola of time difference of arrival—the one-sided hyperbola of time difference of arrival 1 and the one-sided hyperbola of time difference of arrival 2.

Step 3: The two unilateral hyperbolas of the arrival time difference intersect the current travel curve of the train at two points, and the on-board data processing module performs positioning data fusion on the above two intersection points according to the length of the train, and finally obtains the specific position of the train. Among them, the on-vehicle data processing module only completes relatively simple mathematical calculations, which can be realized by using existing ordinary computers. The positioning data fusion specifically refers to the fusion process of taking the midpoint of the two intersection points; first, the above two intersection points are the positions of the front and rear of the vehicle obtained from the positioning of the base station, and their midpoint positions are obtained according to the positions of the front and rear of the vehicle; then , according to the natural extension length of the train at the moment, the midpoint position is moved along the direction of train travel and the opposite direction of train travel respectively by half the train length of the above train length, and the actual position coordinates of the front and rear of the train are obtained

As shown in Figure 3, the traveling curve of the train intersects with the unilateral hyperbola 1 and the unilateral hyperbola 2 respectively at two points. The existence of various error factors in the vehicle makes the obtained positioning point inaccurate, and there is a certain error between the actual position coordinates, but the length of the train, that is, the distance between the front and the rear, is known. The patent of the present invention utilizes For this feature of the train, the midpoint of the position data of the rear and the front of the vehicle obtained by positioning is fused to further improve the positioning accuracy.

As shown in FIG. 4, it is a schematic diagram of positioning data fusion of the LTE-R-based train positioning method using dual mobile stations described in the embodiment of the present invention. First, obtain them according to the positions A1 and B1 of the front and rear of the train obtained from the positioning. Then, according to the natural stretching length of the train at the moment, move C1 along the traveling direction of the train and the opposite direction of the train traveling by half the distance of the above-mentioned train length respectively, and finally obtain the position of the front of the train A2 and the position of the rear of the train B2 , which is the precise train position data.

As shown in Figure 1, the specific positioning process in the work of the present invention is as follows: first, the vehicle-mounted mobile station (ie, the vehicle-mounted sending and receiving module) sends a positioning request to the base station module (ie, the communication base station of the LTE-R communication system), and the base station module Make a response and report the base station service area, thereby determining the base station service area where the train is located and two adjacent positioning service base stations; then, the positioning service base station sends the downlink signal containing the positioning reference signal PRS to the vehicle-mounted mobile station of the train; Finally, the on-board data processing module obtains the specific position data of the train after calculation and processing of data such as positioning parameter estimation and position calculation.

The above embodiments are only exemplary, and will not limit the present invention. It should be pointed out that for those skilled in the art, under the technical inspiration provided by the present invention, other equivalent modifications and improvements made should be regarded as Be the protection scope of the present invention.

Claims (5)

1. the train locating method based on LTE-R utilizing double-movement platform, it is characterised in that: described localization method specifically wraps Include following steps:

Two railways adjacent before and after this communication base station are moved logical by S1: determine that train is currently located the communication base station of service area The communication base station of communication system LTE-R is as positioning service base station, and obtains the position coordinates of the two positioning service base station；By two Individual positioning service base station sends the down link signal of PRS containing location reference signals simultaneously to train；

S2: utilize two vehicle-mounted mobile platforms of be placed in train head and the tailstock to receive above-mentioned framing signal, and by vehicle-mounted data Processing module calculates, and arrives separately at two vehicle-mounted mobiles from the location reference signals PRS of above-mentioned two positioning service base station The time difference of platform, i.e. location reference signals arrival time are poor, and vehicle-mounted data processing module is according to location reference signals arrival time The position coordinates at difference and place, positioning service base station generates two reference signal arrival times poor monolateral hyperbola；

Article S3: two, arrival time differs from monolateral hyperbola travel curve current with train respectively and intersects at two points, vehicle-mounted data Above-mentioned two intersection point is carried out positioning data fusion by processing module further according to train length, finally gives the position of train.

2. a kind of train locating method based on LTE-R utilizing double-movement platform according to claim 1, it is characterised in that: Positioning data fusion in above-mentioned steps S3 specifically refers to take two intersection points wherein carry out fusion treatment；First, above-mentioned two Individual intersection point is headstock and the tailstock position that architecture obtains, and tries to achieve their point midway according to headstock and tailstock position； Then, the opposite direction that point midway is advanced along train direct of travel and train is divided by the natural spread length according to train this moment Do not move the distance of half train length of above-mentioned train length, obtain the actual position coordinate of train head and the tailstock.

3. a kind of train locating method based on LTE-R utilizing double-movement platform according to claim 1 or claim 2, its feature exists In: described positioning service base station is Distributed localization base station.

4. a kind of train locating method based on LTE-R utilizing double-movement platform according to claim 1 or claim 2, its feature exists In: described vehicle-mounted mobile platform refers to be respectively arranged at two mobile stations of train head and the tailstock, and each mobile station is each wrapped Containing a set of signal sending and receiving devices.

5. a kind of train locating method based on LTE-R utilizing double-movement platform according to claim 1 or claim 2, its feature exists In: described location reference signals PRS be GSM LTE-R introduce in protocol specification be specifically designed to wireless location Signal, it is adaptable to subcarrier spacing is the situation of 15kHz, on antenna port 6 transmit, for positioning location reference signals Antenna port transmits, reduces the interference between reference signal and useful signal.