INDOOR POSITIONING METHOD AND APPARATUS

Description

TECHNICAL FIELD

The present disclosure relates to the field of communications technologies, and in particular, to an indoor positioning method and an apparatus.

BACKGROUND

At present, with development of mobile communications technologies and a growth of service requirements, positioning services based on a location of a mobile terminal are increasing. Positioning-based services relate to many fields, such as transportation, logistics, public security, emergency service, and daily life, and can provide numerous services, such as navigation, logistics management, transportation information, and scheduling. Therefore, the services are applied widely.

Positioning methods defined in the 3GPP (3^rdGeneration Partnership Project) protocol include an E-CID (enhanced cell identification) positioning method and an OTDOA (observed time difference of arrival) positioning method.

The E-CID positioning method is usually used in cellular mobile communications, and can be easily implemented. In this positioning manner, each cell has its own specific cell identity number (Cell ID). When entering a cell, a mobile terminal needs to register in the current cell, and then data on a positioning server includes a cell identity of the corresponding cell. The positioning server determines a location of the mobile terminal according to a collected identity of a cell in which the mobile terminal is located.

The OTDOA is a common positioning method. As shown in FIG. 1, the mobile terminal listens to a base station, and measures an RSTD (reference signal time difference). One measurement value is obtained for every two base stations, and one hyperbola positioning area is formed. Therefore, two hyperbola positioning areas are obtained for three base stations. A boundary point may be solved, and an exact location of the mobile terminal may be obtained.

Location information in a horizontal direction and location information in a vertical direction of a target object can be finally obtained in a positioning process. In the foregoing two methods, regardless of an indoor scenario or an outdoor scenario, all pieces of location information in the vertical direction obtained by means of positioning are an altitude and altitude uncertainty of the mobile terminal. However, when the mobile terminal is located indoors, if the altitude and the altitude uncertainty of the mobile terminal are used to indicate the location information in the vertical direction, positioning accuracy is relatively low.

In conclusion, the current indoor positioning method has a disadvantage of relatively low accuracy.

SUMMARY

Embodiments of the present invention provide an indoor positioning method and an apparatus, so as to overcome a disadvantage of relatively low accuracy in the prior art.

Specific technical solutions provided in the embodiments of the present invention are as follows:

According to a first aspect, an indoor positioning method is provided, including:

obtaining, by a positioning server, floor numbers of floors on which at least one base station is located;

receiving, by the positioning server, identification information of a first terminal;

determining, by the positioning server, the first terminal according to the identification information; and

determining, by the positioning server, vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located.

With reference to the first aspect, in a first possible implementation, the floor numbers of the floors on which the at least one base station is located include a floor number of a floor on which a first base station is located, where the first base station is a serving base station of the first terminal; and

the determining, by the positioning server, vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located includes:

using, by the positioning server, the floor number of the floor on which the first base station is located as the vertical location information of the first terminal.

With reference to the first aspect, in a second possible implementation, before the determining, by the positioning server, vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located, the method further includes:

sending, by the positioning server, a reference signal sending instruction message to N base stations, where the reference signal sending instruction message is used to instruct the N base stations to separately broadcast a reference signal, and N is a positive integer greater than 0;

sending, by the positioning server, a reference signal receiving instruction message to the first terminal, where the reference signal receiving instruction message is used to instruct the first terminal to receive reference signals broadcast by the N base stations and to feed back N reference signal time differences, the N reference signal time differences are obtained by separately subtracting an arrival time of a reference signal broadcast by a reference base station from arrival times of the reference signals broadcast by the N base stations, and the reference base station is any one of the N base stations;

receiving, by the positioning server, the N reference signal time differences; and

determining, by the positioning server according to the N reference signal time differences a base station corresponding to a reference signal with a shortest arrival time; where

the floor numbers of the floors on which the at least one base station is located include a floor number of a floor on which the base station corresponding to the reference signal with the shortest arrival time is located; and

using, by the positioning server, the floor number of the floor on which the base station corresponding to the reference signal with the shortest arrival time is located as the vertical location information of the first terminal.

With reference to the first aspect, in a third possible implementation, before the determining, by the positioning server, vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located, the method further includes:

sending, by the positioning server, a reference signal sending instruction message to M base stations, where the reference signal sending instruction message is used to instruct the M base stations to separately broadcast a reference signal, and M is a positive integer greater than 2;

sending, by the positioning server, a reference signal receiving instruction message to the first terminal, where the reference signal receiving instruction message is used to instruct the first terminal to receive reference signals broadcast by the M base stations and to feed back M reference signal time differences, the M reference signal time differences are obtained by separately subtracting an arrival time of a reference signal broadcast by a reference base station from arrival times of the reference signals broadcast by the M base stations, and the reference base station is any one of the M base stations;

receiving, by the positioning server, the M reference signal time differences; and

receiving, by the positioning server, vertical altitudes of the M base stations that are sent by the M base stations; where

the floor numbers of the floors on which the at least one base station is located include floor numbers of floors on which the M base stations are located; and

obtaining, by the positioning server, a first function relationship according to a mapping relationship between the vertical altitudes of the M base stations and the floor numbers of the M base stations, where the first function relationship is used to represent a correspondence between a floor number and a vertical altitude;

calculating, by the positioning server, a vertical altitude of the first terminal according to the M reference signal time differences; and

converting, by the positioning server according to the first function relationship, the vertical altitude that is of the first terminal and that is obtained by means of calculation into a floor number, and using the floor number obtained by means of conversion as the vertical location information of the first terminal.

With reference to the first aspect, in a fourth possible implementation, before the determining, by the positioning server, vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located, the method further includes:

sending, by the positioning server, a reference signal receiving instruction message to the first terminal, where the reference signal receiving instruction message is used to instruct the first terminal to receive reference signals broadcast by the M base stations and to feed back M reference signal time differences, the M reference signal time differences are obtained by separately subtracting an arrival time of a reference signal broadcast by a reference base station from arrival times of the reference signals broadcast by the M base stations, and the reference base station is any one of the M base stations;

receiving, by the positioning server, the M reference signal time differences;

receiving, by the positioning server, M receive powers sent by the first terminal, where the M receive powers are powers used by the first terminal to receive the reference signals broadcast by the M base stations; and

receiving, by the positioning server, vertical altitudes of the M base stations that are sent by the M base stations; where

the floor numbers of the floors on which the at least one base station is located include floor numbers of floors on which the M base stations are located; and

obtaining, by the positioning server, a second function relationship according to a mapping relationship between the vertical altitudes of the M base stations and the floor numbers of the M base stations, where the second function relationship is used to represent a correspondence between a floor number and a vertical altitude;

calculating, by the positioning server, a first vertical altitude of the first terminal according to the M reference signal time differences;

calculating, by the positioning server, a second vertical altitude of the first terminal according to the M receive powers;

obtaining, by the positioning server, a final vertical altitude of the first terminal according to the first vertical altitude and the second vertical altitude; and

converting, by the positioning server according to the second function relationship, the final vertical altitude that is of the first terminal and that is obtained by means of calculation into a floor number, and using the floor number obtained by means of conversion as the vertical location information of the first terminal.

With reference to any one of the second to the fourth possible implementations of the first aspect, in a fifth possible implementation, before the obtaining, by a positioning server, floor numbers of floors on which at least one base station is located, the method further includes:

sending, by the positioning server, a positioning measurement request.

According to a second aspect, an indoor positioning method is provided, including:

determining, by a base station, a floor number of a floor on which the base station is located; and

sending, by the base station, the floor number to a positioning server.

With reference to the second aspect, in a first possible implementation, the method further includes:

sending, by the base station, identification information of a first terminal to the positioning server, where the base station is a serving base station of the first terminal.

With reference to the second aspect, in a second possible implementation, the method further includes:

receiving, by the base station, a reference signal sending instruction message sent by the positioning server; and

broadcasting, by the base station, a reference signal according to the reference signal sending instruction message; where

the base station is a base station corresponding to a reference signal with a shortest arrival time among N reference signal time differences sent by a first terminal, the N reference signal time differences are obtained by separately subtracting an arrival time of a reference signal broadcast by a reference base station from arrival times of reference signals broadcast by N base stations, the reference base station is any one of the N base stations, and N is a positive integer greater than 0.

With reference to the second aspect, in a third possible implementation, the method further includes:

receiving, by the base station, a reference signal sending instruction message sent by the positioning server;

broadcasting, by the base station, a reference signal according to the reference signal sending instruction message; and

sending, by the base station, a vertical altitude of the base station.

With reference to any one of the second aspect, or the first to the third possible implementations of the second aspect, in a fourth possible implementation, before the sending, by the base station, the floor number to a positioning server, the method further includes:

receiving, by the base station, a positioning measurement request sent by the positioning server; or

receiving, by the base station, a positioning measurement request sent by a terminal served by the base station.

According to a third aspect, a positioning server is provided, including:

an obtaining unit, configured to obtain floor numbers of floors on which at least one base station is located;

a receiving unit, configured to receive identification information of a first terminal; and

a determining unit, configured to determine the first terminal according to the identification information; where

the determining unit is further configured to determine vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located.

With reference to the third aspect, in a first possible implementation, the floor numbers of the floors on which the at least one base station is located include a floor number of a floor on which a first base station is located, where the first base station is a serving base station of the first terminal; and

when determining the vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located, the determining unit is specifically configured to:

use the floor number of the floor on which the first base station is located as the vertical location information of the first terminal.

With reference to the third aspect, in a second possible implementation, a sending unit is further included, and the sending unit is configured to:

send a reference signal sending instruction message to N base stations, where the reference signal sending instruction message is used to instruct the N base stations to separately broadcast a reference signal, and N is a positive integer greater than 0; where

the sending unit is further configured to send a reference signal receiving instruction message to the first terminal, where the reference signal receiving instruction message is used to instruct the first terminal to receive reference signals broadcast by the N base stations and to feed back N reference signal time differences, the N reference signal time differences are obtained by separately subtracting an arrival time of a reference signal broadcast by a reference base station from arrival times of the reference signals broadcast by the N base stations, and the reference base station is any one of the N base stations;

the receiving unit is further configured to receive the N reference signal time differences;

the determining unit is further configured to determine, according to the N reference signal time differences, a base station corresponding to a reference signal with a shortest arrival time;

the floor numbers that are of the floors on which the at least one base station is located and obtained by the obtaining unit include a floor number of a floor on which the base station corresponding to the reference signal with the shortest arrival time is located; and

use the floor number of the floor on which the base station corresponding to the reference signal with the shortest arrival time is located as the vertical location information of the first terminal.

With reference to the third aspect, in a third possible implementation, a sending unit is further included, and the sending unit is configured to:

send a reference signal sending instruction message to M base stations, where the reference signal sending instruction message is used to instruct the M base stations to separately broadcast a reference signal, and M is a positive integer greater than 2; where

the sending unit is further configured to send a reference signal receiving instruction message to the first terminal, where the reference signal receiving instruction message is used to instruct the first terminal to receive reference signals broadcast by the M base stations and to feed back M reference signal time differences, the M reference signal time differences are obtained by separately subtracting an arrival time of a reference signal broadcast by a reference base station from arrival times of the reference signals broadcast by the M base stations, and the reference base station is any one of the M base stations;

the receiving unit is further configured to receive the M reference signal time differences;

the receiving unit is further configured to receive vertical altitudes of the M base stations that are sent by the M base stations;

the floor numbers that are of the floors on which the at least one base station is located and obtained by the obtaining unit include floor numbers of floors on which the M base stations are located; and

obtain a first function relationship according to a mapping relationship between the vertical altitudes of the M base stations and the floor numbers of the M base stations, where the first function relationship is used to represent a correspondence between a floor number and a vertical altitude;

calculate a vertical altitude of the first terminal according to the M reference signal time differences; and

convert, according to the first function relationship, the vertical altitude that is of the first terminal and that is obtained by means of calculation into a floor number, and use the floor number obtained by means of conversion as the vertical location information of the first terminal.

With reference to the third aspect, in a fourth possible implementation, a sending unit is further included, and the sending unit is configured to:

the sending unit is further configured to send a reference signal receiving instruction message to the first terminal, where the reference signal receiving instruction message is used to instruct the first terminal to receive reference signals broadcast by the M base stations and to feed back M reference signal time differences, the M reference signal time differences are obtained by separately subtracting an arrival time of a reference signal broadcast by a reference base station from arrival times of the reference signals broadcast by the M base stations, and the reference base station is any one of the M base stations;

the receiving unit is further configured to receive the M reference signal time differences;

the receiving unit is further configured to receive M receive powers sent by the first terminal, where the M receive powers are powers used by the first terminal to receive the reference signals broadcast by the M base stations;

the receiving unit is further configured to receive vertical altitudes of the M base stations that are sent by the M base stations;

obtain a second function relationship according to a mapping relationship between the vertical altitudes of the M base stations and the floor numbers of the M base stations, where the second function relationship is used to represent a correspondence between a floor number and a vertical altitude;

calculate a first vertical altitude of the first terminal according to the M reference signal time differences;

calculate a second vertical altitude of the first terminal according to the M receive powers;

obtain a final vertical altitude of the first terminal according to the first vertical altitude and the second vertical altitude; and

convert, according to the second function relationship, the final vertical altitude that is of the first terminal and that is obtained by means of calculation into a floor number, and use the floor number obtained by means of conversion as the vertical location information of the first terminal.

With reference to any one of the second to the fourth possible implementations of the third aspect, in a fifth possible implementation, the sending unit is further configured to:

send a positioning measurement request.

According to a fourth aspect, a base station is provided, including:

a determining unit, configured to determine a floor number of a floor on which the base station is located; and

a sending unit, configured to send the floor number to a positioning server.

With reference to the fourth aspect, in a first possible implementation, the sending unit is further configured to:

send identification information of a first terminal to the positioning server, where the base station is a serving base station of the first terminal.

With reference to the fourth aspect, in a second possible implementation, a receiving unit is further included, and the receiving unit is configured to:

receive a reference signal sending instruction message sent by the positioning server; where

the sending unit is further configured to broadcast a reference signal according to the reference signal sending instruction message; and

With reference to the fourth aspect, in a third possible implementation, a receiving unit is further included, and the receiving unit is configured to:

receive a reference signal sending instruction message sent by the positioning server; where

the sending unit is further configured to broadcast a reference signal according to the reference signal sending instruction message; and

the sending unit is further configured to send a vertical altitude of the base station.

With reference to any one of the fourth aspect, or the first to the third possible implementations of the fourth aspect, in a fourth possible implementation, the receiving unit is further configured to:

receive a positioning measurement request sent by the positioning server; or

receive a positioning measurement request sent by a terminal served by the base station.

The embodiments of the present invention provide an indoor positioning method. In this solution, a positioning server obtains floor numbers of floors on which at least one base station is located; the positioning server receives identification information of a first terminal; the positioning server determines the first terminal according to the identification information; and the positioning server determines vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located. When a terminal is located indoors, positioning is meaningful only when a specific floor on which the terminal is located is determined. In the solution, when the terminal is located indoors, in addition to a vertical altitude of the terminal, a specific floor on which the terminal is located is determined. Therefore, positioning accuracy is improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of OTDOA positioning in the prior art;

FIG. 2A is a schematic diagram of an indoor positioning scenario according to an embodiment of the present invention;

FIG. 2B is a flowchart of indoor positioning according to an embodiment of the present invention;

FIG. 3 is another flowchart of indoor positioning according to an embodiment of the present invention;

FIG. 4A is an embodiment of indoor positioning according to an embodiment of the present invention;

FIG. 4B is another embodiment of indoor positioning according to an embodiment of the present invention;

FIG. 4C is another embodiment of indoor positioning according to an embodiment of the present invention;

FIG. 5A is a schematic structural diagram of a positioning server according to an embodiment of the present invention;

FIG. 5B is another schematic structural diagram of a positioning server according to an embodiment of the present invention;

FIG. 6A is a schematic structural diagram of a base station according to an embodiment of the present invention; and

FIG. 6B is another schematic structural diagram of a base station according to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following clearly describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

Technologies described in this specification may be applied to various communications systems, for example, current 2G and 3G communications systems and a next-generation communications system, such as a GSM (Global System for Mobile Communications), a CDMA (Code Division Multiple Access) system, a TDMA (Time Division Multiple Access) system, a WCDMA (Wideband Code Division Multiple Access) system, an FDMA (Frequency Division Multiple Access) system, an OFDMA (Orthogonal Frequency Division Multiple Access) system, a single-carrier FDMA (SC-FDMA) system, a GPRS (general packet radio service) system, and another similar communications system.

In the following, the embodiments of the present invention are described in detail with reference to the accompanying drawings. It should be understood that the embodiments described herein are merely used to illustrate and explain the present invention, but are not intended to limit the present invention. In addition, the embodiments in this application and features in the embodiments may be mutually combined in a case in which they do not conflict with each other.

The following describes the embodiments of the present invention in detail with reference to the accompanying drawings.

A schematic diagram of an indoor positioning scenario is shown in FIG. 2A.

Referring to FIG. 2B, in this embodiment of the present invention, an indoor positioning procedure is as follows:

Step 200: A positioning server obtains floor numbers of floors on which at least one base station is located.

In this embodiment of the present invention, the floor number may be 2, 3, 4, or the like. The floor number is specifically carried in a message, and the floor number may be a value in a floor index field.

According to the foregoing description, the positioning server needs to obtain the floor numbers of the floors on which the at least one base station is located. However, if the positioning server determines only the floor numbers, but does not learn location information of a building, positioning is meaningless, and accuracy is relatively low. For example, a base station A reports to the positioning server that a floor number of a floor on which the base station A is located is 2. For a terminal 1 served by the base station A, if the positioning server uses the floor number of the floor on which the base station A is located as vertical location information of the terminal 1, that is, the positioning server learns only that the terminal 1 is located on the second floor, but does not learn a specific building in which the terminal 1 is located, thus the positioning is still meaningless. Therefore, in this embodiment of the present invention, the positioning server not only needs to obtain the floor numbers of the floors on which the at least one base station is located, but also needs to obtain coordinate information of a location of the at least one base station, for example, (X, Y, Z). In this way, the positioning server can determine, according to the coordinate information sent by the base station, a building in which the base station is located, and can determine, according to the floor number, a specific floor on which the terminal is located, so that accurate positioning can be implemented.

However, a current protocol has specified that a base station needs to send coordinate information of a location of the base station to a positioning server when positioning is performed. Therefore, details are not described herein.

In this embodiment of the present invention, if the positioning server needs to obtain the floor numbers of the floors on which the at least one base station is located, for any base station in the at least one base station, the base station needs to receive a positioning measurement request message, so that the base station can be triggered to send a floor number of a floor on which the base station is located. The positioning measurement request message may be sent by the positioning server, or may be sent by a terminal served by the base station. If the positioning measurement request message is to be sent by the positioning server, the positioning server needs to send the positioning measurement request message before obtaining the floor numbers of the floors on which the at least one base station is located.

In this embodiment of the present invention, the positioning server may send the positioning measurement request in real time or periodically.

In this embodiment of the present invention, the positioning measurement request may be an E-CID measurement initiation request.

Step 210: The positioning server receives identification information of a first terminal.

In this embodiment of the present invention, the identification information of the first terminal may be a TMSI (temporary mobile subscriber identity), or may be an IMSI (international mobile subscriber identity), or certainly may be information in another form. Details are not described herein.

In this embodiment of the present invention, there is no sequence relationship between step 200 and step 210. That is, it may be that after the positioning server obtains the floor numbers of the floors on which the at least one base station is located, the positioning server receives the identification information of the first terminal. Alternatively, it may be that after the positioning server receives the identification information of the first terminal, the positioning server obtains the floor numbers of the floors on which the at least one base station is located.

Step 220: The positioning server determines the first terminal according to the identification information.

Step 230: The positioning server determines vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located.

In this embodiment of the present invention, optionally, the floor numbers of the floors on which the at least one base station is located include a floor number of a floor on which a first base station is located. The first base station is a serving base station of the first terminal.

In this case, the positioning server may determine, in multiple manners, the vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located. Optionally, the following manner may be used:

using, by the positioning server, the floor number of the floor on which the first base station is located as the vertical location information of the first terminal.

For example, there are three base stations in a positioning area: a base station 1, a base station 2, and a base station 3. The positioning server sends a positioning measurement request to the three base stations. The base station 1 serves 10 terminals: a terminal 1 to a terminal 10; the base station 2 also serves 10 terminals: a terminal 11 to a terminal 20; and the base station 3 also serves 10 terminals: a terminal 21 to a terminal 30. The base station 1 sends, to the positioning server, a floor number of the base station 1 and identification information of each terminal in the terminal 1 to the terminal 10. Likewise, the base station 2 sends, to the positioning server, a floor number of the base station 2 and identification information of each terminal in the terminal 11 to the terminal 20; and the base station 3 sends, to the positioning server, a floor number of the base station 3 and identification information of each terminal in the terminal 21 to the terminal 30. The positioning server uses the floor number of the base station 1 as vertical location information of the terminal 1 to the terminal 10; the positioning server uses the floor number of the base station 2 as vertical location information of the terminal 11 to the terminal 20; and the positioning server uses the floor number of the base station 3 as vertical location information of the terminal 21 to the terminal 30.

According to the foregoing description, a floor number of a floor on which a serving base station of a terminal is located is used as vertical location information of the terminal. However, because accuracy is relatively low, to further improve positioning accuracy, the following manner may further be used:

Before the positioning server determines the vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located, the following operations may further be included: sending, by the positioning server, a reference signal sending instruction message to N base stations, where the reference signal sending instruction message is used to instruct the N base stations to separately broadcast a reference signal, and N is a positive integer greater than 0;

receiving, by the positioning server, the N reference signal time differences; and

determining, by the positioning server according to the N reference signal time differences, a base station corresponding to a reference signal with a shortest arrival time; where

For example, there are three base stations in a positioning area: a base station 1, a base station 2, and a base station 3. The base station 1 serves a terminal A and a terminal B. The positioning server sends a reference signal sending instruction message to all the three base stations. The base station 1, the base station 2, and the base station 3 each begin to broadcast a reference signal after receiving the reference signal sending instruction message. If the positioning server needs to position the terminal A, the positioning server sends a reference signal receiving instruction message to the terminal A. After receiving the reference signal receiving instruction message, the terminal A receives reference signals respectively broadcast by the base station 1, the base station 2, and the base station 3. A time of receiving, by the terminal A, a reference signal broadcast by the base station 1 is 1 s, a time of receiving a reference signal broadcast by the base station 2 is 2 s, and a time of receiving a reference signal broadcast by the base station 3 is 3 s. If a reference base station is the base station 3, a time difference of the reference signal broadcast by the base station 1 and received by the terminal A is −2 s, a time difference of the reference signal broadcast by the base station 2 and received by the terminal A is −1 s, and a time difference of the reference signal broadcast by the base station 3 and received by the terminal A is 0 s. Therefore, a base station corresponding to a reference signal with a shortest arrival time is the base station 1.

For another example, there are three base stations in a positioning area: a base station 1, a base station 2, and a base station 3. The base station 1 serves a terminal A and a terminal B. The positioning server sends a reference signal sending instruction message to all the three base stations. The base station 1, the base station 2, and the base station 3 each begin to broadcast a reference signal after receiving the reference signal sending instruction message. If the positioning server needs to position the terminal A, the positioning server sends a reference signal receiving instruction message to the terminal A. After receiving the reference signal receiving instruction message, the terminal A receives reference signals respectively broadcast by the base station 1, the base station 2, and the base station 3. A time of receiving, by the terminal A, a reference signal broadcast by the base station 1 is 1 s, a time of receiving a reference signal broadcast by the base station 2 is 2 s, and a time of receiving a reference signal broadcast by the base station 3 is 3 s. If a reference base station is the base station 1, a time difference of the reference signal broadcast by the base station 1 and received by the terminal A is 0 s, a time difference of the reference signal broadcast by the base station 2 and received by the terminal A is 1 s, and a time difference of the reference signal broadcast by the base station 3 and received by the terminal A is 2 s. Therefore, a base station corresponding to a reference signal with a shortest arrival time is the base station 1.

The foregoing describes a process in which the base station corresponding to the reference signal with the shortest arrival time is determined for the terminal A. A process in which a base station corresponding to a reference signal with a shortest arrival time is determined for the terminal B is similar to the process for the terminal A. Details are not described herein again.

The foregoing example is still used for description. For the terminal A, if it is determined that a base station corresponding to a reference signal with a shortest arrival time is the base station 1, a floor number of a floor on which the base station 1 is located is used as vertical location information of the terminal A. Likewise, for the terminal B, if it is determined that a base station corresponding to a reference signal with a shortest arrival time is the base station 2, a floor number of a floor on which the base station 2 is located is used as vertical location information of the terminal B.

In this embodiment of the present invention, the step of determining, by the positioning server according to the N reference signal time differences, a base station corresponding to a reference signal with a shortest arrival time may be performed before or after the step of obtaining, by a positioning server, floor numbers of floors on which at least one base station is located. If the step of determining, by the positioning server according to the N reference signal time differences, a base station corresponding to a reference signal with a shortest arrival time is performed before the step of obtaining, by a positioning server, floor numbers of floors on which at least one base station is located, after determining, according to the N reference signal time differences, the base station corresponding to the reference signal with the shortest arrival time, the positioning server only needs to obtain a floor number of a floor on which the base station corresponding to the reference signal with the shortest arrival time is located.

If the step of determining, by the positioning server according to the N reference signal time differences, a base station corresponding to a reference signal with a shortest arrival time is performed after the step of determining, by a positioning server, floor numbers of floors on which at least one base station is located, after determining, according to the N reference signal time differences, the base station corresponding to the reference signal with the shortest arrival time, the positioning server searches, in the obtained floor numbers of the floors on which the at least one base station is located, for a floor number of a floor on which the base station corresponding to the reference signal with the shortest arrival time is located.

A sequence between the step of determining, by the positioning server according to the N reference signal time differences, a base station corresponding to a reference signal with a shortest arrival time and the step of obtaining, by a positioning server, floor numbers of floors on which at least one base station is located is relatively flexible, and is not specifically limited herein.

Likewise, to further improve positioning accuracy, the following manner may further be used:

sending, by the positioning server, a reference signal receiving instruction message to the first terminal, where the reference signal receiving instruction message is used to instruct the first terminal to receive reference signals broadcast by the M base stations and to feed back M reference signal time differences, the M reference signal time differences are obtained by separately subtracting an arrival time of a reference signal broadcast by a reference base station from arrival times of the reference signals broadcast by the M base stations, and the reference base station is any one of the M base stations;

receiving, by the positioning server, the M reference signal time differences; and

receiving, by the positioning server, vertical altitudes of the M base stations that are sent by the M base stations; where

the floor numbers of the floors on which the at least one base station is located include floor numbers of floors on which the M base stations are located.

For example, there are three base stations in a positioning area: a base station 1, a base station 2, and a base station 3. The base station 1 serves a terminal A and a terminal B. The positioning server sends a reference signal sending instruction message to all the three base stations. The base station 1, the base station 2, and the base station 3 each begin to broadcast a reference signal after receiving the reference signal sending instruction message. If the positioning server needs to position the terminal A, the positioning server sends a reference signal receiving instruction message to the terminal A. After receiving the reference signal receiving instruction message, the terminal A receives reference signals respectively broadcast by the base station 1, the base station 2, and the base station 3. A time of receiving, by the terminal A, a reference signal broadcast by the base station 1 is 1 s, a time of receiving a reference signal broadcast by the base station 2 is 2 s, and a time of receiving a reference signal broadcast by the base station 3 is 3 s. If a reference base station is the base station 3, a time difference of the reference signal broadcast by the base station 1 and received by the terminal A is −2 s, a time difference of the reference signal broadcast by the base station 2 and received by the terminal A is −1 s, and a time difference of the reference signal broadcast by the base station 3 and received by the terminal A is 0 s. The positioning server receives three reference signal time differences: −2 s, −1 s, and 0 s; and the positioning server further receives vertical altitudes of the three base stations that are sent by the three base stations. The floor numbers of the floors on which the at least one base station is located include floor numbers of floors on which the three base stations are located.

In this case, when the positioning server determines the vertical location information of the first terminal according to the floor numbers of the floors on which the at least one base station is located, optionally, the following manner may be used: obtaining, by the positioning server, a first function relationship according to a mapping relationship between the vertical altitudes of the M base stations and the floor numbers of the M base stations, where the first function relationship is used to represent a correspondence between a floor number and a vertical altitude;

calculating, by the positioning server, a vertical altitude of the first terminal according to the M reference signal time differences; and

For example, a vertical altitude of the base station 1 is 100 meters, and a floor number is 1; a vertical altitude of the base station 2 is 103 meters, and a floor number is 2; and a vertical altitude of the base station 3 is 106 meters, and a floor number is 3. It may be obtained according to the base station 1 and the base station 2: vertical altitude/floor number=(103−100)/(2−1)=3; it may be obtained according to the base station 2 and the base station 3: vertical altitude/floor number=(106−103)/(3−2)=3; and it may be obtained according to the base station 1 and the base station 3: vertical altitude/floor number=(106−100)/(3−1)=3. Therefore, it may be obtained that vertical altitude/floor number is (3+3+3)/3=3, and the first function relationship may be y=3x+b, where y is a vertical altitude, and x is a floor number. It may be obtained that b is 97 by substituting a vertical altitude and a floor number of any one of the base station 1, the base station 2, or the base station 3 into the first function relationship. Therefore, the first function relationship is y=3x+97.

For another example, a vertical altitude of the base station 1 is 100 meters, and a floor number is 1; a vertical altitude of the base station 2 is 106 meters, and a floor number is 2; and a vertical altitude of the base station 3 is 109 meters, and a floor number is 3. It may be obtained according to the base station 1 and the base station 2: vertical altitude/floor number=(106−100)/(2−1)=6; it may be obtained according to the base station 2 and the base station 3: vertical altitude/floor number=(109−106)/(3−2)=3; and it may be obtained according to the base station 1 and the base station 3: vertical altitude/floor number=(109−100)/(3−1)=4.5. Therefore, it may be obtained that vertical altitude/floor number is (6+3+4.5)/3=4.5, and the first function relationship may be y=4.5x+b, where y is a vertical altitude, and x is a floor number. It may be obtained that b is 95.5 by substituting the vertical altitude and the floor number of the base station 1 into the first function relationship; it may be obtained that b is 97 by substituting the vertical altitude and the floor number of the base station 2 into the first function relationship; and it may be obtained that b is 95.5 by substituting the vertical altitude and the floor number of the base station 3 into the first function relationship. Therefore, b is (95.5+95.5+97)/3=96, and the first function relationship is y=4.5x+96.

Therefore, after the first function relationship is obtained, if the vertical altitude of the first terminal is 120 meters, it may be obtained that x is 5.3 by substituting y=120 into the first function relationship, and the floor number of 5.3 may be rounded up to 6. If the vertical altitude of the first terminal is 118.5 meters, it may be obtained that x is 5 by substituting y=118.5 into the first function relationship.

In this embodiment of the present invention, calculating the vertical altitude of the first terminal according to the M reference signal time differences is a relatively common technology that is currently used. Details are not described herein.