CN109581446B

CN109581446B - Indoor positioning system and positioning method

Info

Publication number: CN109581446B
Application number: CN201811462199.4A
Authority: CN
Inventors: 董孝峰; 姜长龙; 钟波; 孙媌媌
Original assignee: Boruitaike Science And Technology Ningbo Co ltd
Current assignee: Boruitaike Science And Technology Ningbo Co ltd
Priority date: 2018-11-30
Filing date: 2018-11-30
Publication date: 2023-08-11
Anticipated expiration: 2038-11-30
Also published as: CN109581446A

Abstract

The invention discloses a positioning system and a positioning method which can be used indoors, wherein the method comprises the following steps: first step, determining LBS base station coordinates: the method comprises the steps that GNSS coordinates of a mobile terminal can be obtained by using the characteristic of GNSS signal positioning in an outdoor environment, the mobile terminal sends a positioning request message to a positioning service center, the positioning service center sends a positioning message to the mobile terminal, the mobile terminal replies a positioning message, calculates the positioning message, obtains a pseudo range from the mobile terminal to an LBS base station, and calculates the coordinates of the LBS base station by using the pseudo range and the GNSS coordinates of the mobile terminal; and step two, calculating coordinates of the mobile terminal: the mobile terminal sends a positioning request message, the positioning service center sends a positioning message to the mobile terminal, the mobile terminal and the WPS base station receive the positioning message and send a positioning message return message to the positioning service center, the positioning message return messages of the mobile terminal and the WPS base station are compared and calculated to obtain a pseudo range from the mobile terminal to the LBS base station, and the pseudo range from the mobile terminal to the LBS base station and the coordinates of the LBS base station are utilized to calculate the coordinates of the mobile terminal.

Description

Indoor positioning system and positioning method

Technical Field

The invention relates to a target positioning technology, in particular to a positioning system and a positioning method which can be used indoors.

Background

People go out more and more from electronic maps, positioning and navigation services.

Early radio positioning systems, such as the rowland system, the meridian navigation system, and the long river system of china, have been mainly used for sea defense and shipping, and are currently eliminated by the global satellite positioning system GNSS (Global Navigation Satellite System). Currently available wide area location service systems include the GPS, BDS, GLONASS, GALILEO, IRNSS and QZSS 6 large satellite navigation systems. GPS, BDS, GLONASS, GALILEO has achieved global coverage.

In the GNSS positioning process, the terminal simultaneously tracks a plurality of satellites, simultaneously receives positioning messages of the plurality of satellites, selects signals of at least 4 satellites with good signals for resolving, and calculates local coordinates. In order to improve the positioning accuracy of the GNSS system, a differential positioning method is proposed, and the purposes of improving the positioning accuracy are achieved by eliminating common errors and common parameters. In the GNSS positioning process, there are three part errors. The first part is present for mobile terminals, such as satellite clock errors, ephemeris errors, ionosphere errors, troposphere errors, etc.; the second part is propagation delay error, which cannot be measured by the mobile terminal or calculated by the correction model; the third part is errors inherent to the mobile terminal, such as internal noise, channel delays, multipath effects, etc. The first part of the error can be completely eliminated by using the differential technology, the second part of the error can be mostly eliminated, which mainly depends on the distance between the reference receiver and the mobile terminal, and the third part of the error can not be eliminated.

The working principle is that a GPS reference station is erected on a known control point on the ground in a certain area range, GPS positioning information is recorded in real time by the GPS reference station, the correction quantity of the mobile station in the area is obtained by comparing the GPS reference station with the actual coordinate value of the known control point on the ground, the correction quantity is sent to the mobile terminal, and the measured value of the mobile terminal is corrected to obtain a more accurate measured value. The differential technology also comprises a single-difference method, a double-difference method and a triple-difference method, and the information sent by the base station can be divided into position difference, pseudo-range difference, carrier phase difference and the like, and the purpose of the methods is to eliminate the first part error and the second part error in the three part errors and improve the positioning precision.

In addition to GNSS systems, assisted positioning service systems a-GPS, pseudolite positioning, cellular network positioning (LBS, location Based Service) have also been developed in various countries. Because the indoor positioning can not directly use satellite signals, the research and development investment of enterprises on a positioning system is relatively large, and methods such as UWB positioning, infrared (IR) positioning, bluetooth positioning, RFID positioning, zigBee positioning, wiFi positioning, ultrasonic positioning and the like which can be used for local positioning are developed. These methods have advantages and disadvantages:

UWB has many advantages in the field of construction monitoring: 1) The UWB technology wood has strong anti-interference capability, and the positioning in the indoor, outdoor and near wall bodies becomes feasible; 2) When four or more receivers with different heights exist, three-dimensional accurate positioning can be obtained, the number of the receivers with different heights is large, and the positioning precision is higher; 3) The UWB technology has high data transmission rate, and the delay time of positioning is far smaller than that of other indoor positioning technologies such as Bluetooth positioning, wiFi positioning and the like.

The disadvantages of UWB are: 1) A perfect positioning network is needed, 3 positioning base stations are needed to support any positioning point, and if the number of the base stations is reduced, the positioning accuracy is greatly affected; 2) No obstacle can be present to block radio emission; 3) The basis of UWB positioning is that the base stations need to be synchronized, even a slight network out of synchronization can result in a relatively large deviation in positioning accuracy.

The infrared technology indoor positioning has relatively high indoor positioning precision. However, since the light cannot pass through the obstacle, the infrared rays can only propagate in visual range and are easily interfered by other lights, and the transmission distance of the infrared rays is shorter, so that the indoor positioning effect is poor.

Bluetooth positioning is mainly applied to small-range positioning, for example: a single floor lobby or warehouse. For the mobile terminal equipment integrated with the Bluetooth function, the Bluetooth indoor positioning system can judge the position of the mobile terminal equipment as long as the Bluetooth function of the equipment is started. However, for complex space environments, the stability of the bluetooth positioning system is slightly poor and is greatly disturbed by noise signals.

The RFID positioning technology can obtain centimeter-level positioning precision information in a few milliseconds, and has the advantages of large transmission range, low cost and relatively stable equipment. The disadvantage of RFID is that if the same accuracy requirements are to be met, the deployment of the RFID base station or reader is relatively complex and more numerous than UWB positioning.

The ZigBee positioning technology has the advantages of low power consumption, low cost, short time delay, high capacity, high safety and long transmission distance; the network topology, tree topology and star topology can be supported, the networking is flexible, and multi-hop transmission can be realized; the method has the defects of low transmission rate and high positioning accuracy requirement on the algorithm.

The ultrasonic positioning mainly adopts a reflection type distance measurement method, the whole positioning precision is higher, the structure is simple, but the ultrasonic wave is greatly affected by multipath effect and non-line-of-sight propagation, the ultrasonic frequency is affected by Doppler effect and temperature, and meanwhile, a large amount of infrastructure hardware facilities are required, and the cost is higher.

The local positioning method can provide high-precision positioning, such as UWB, zigBee, IR, RFID and other methods described above can provide centimeter-level positioning precision, but the coverage range is generally in the range of 1-100 meters, so that the method is suitable for small-range industrial scenes and is not suitable for large-area application and popularization.

Currently, the mainstream WiFi positioning adopts the positioning principle of base station side signal intensity RSSI (Received Signal Strength Indicator), so that the precision is relatively low. Under the indoor condition, the mobile phone can search SSID information of a plurality of WiFi base stations, all WiFi terminals send out a Probe Request frame before connecting the WiFi base stations, all channels in the space are traversed, and the WiFi base stations wait for returning to the Probe Response frame. In the interaction process, the terminal broadcasts the self MAC address in the message, the WiFi base station can receive the message packet carrying the mobile phone MAC address and the signal intensity, and the WiFi base station completely acquires the signal intensity value of the mobile phone side, so that the terminal can be positioned in an RSSI mode and the like; the mobile phone side signal strength Rx (Received power) positioning principle is the same as that of the base station side signal strength RSSI positioning principle, the mobile phone also receives a message packet which is measured by a WiFi base station and carries the MAC address and the signal strength of the WiFi base station, and the positioning is realized by adopting the modes of RSSI and the like.

The WiFi positioning method generally performs positioning calculation by using a positioning engine on a base station or a rear positioning server, and finally obtains relative position coordinates. The simplest way is to directly use the position information of the WiFi base station as the position information of the mobile phone terminal, and the accuracy of the position coordinates is within the signal coverage range of the WiFi base station. If several base stations can collect collected fingerprint information at the same time, a weighting algorithm based on the RSSI field strength can be performed to calculate the relative position, but since the propagation model of the wireless signal has continuous fluctuation of field strength in space, the WiFi positioning accuracy mainly depends on the density of the WiFi base stations, and the optimization scope of the positioning algorithm is very small.

The main disadvantage of WiFi positioning is the low accuracy and no azimuth. The average distance from the mobile phone to the WiFi base station is generally about 5 meters. Directivity is lacking because WiFi is typically an omni-directional antenna, so it is difficult to determine if a user is in this room or another room against a wall. WiFi positioning cannot be used in environments where accurate real-time positioning is required. And secondly, the work load of WiFi positioning to the position map is larger, the WiFi positioning is to acquire relative coordinates, namely the coordinates of the mobile phone relative to the WiFi base station, and the map needs to be corrected after the WiFi base station changes. Again, the disadvantage of WiFi positioning is that the quality of the WiFi base station is unstable, resulting in that the quality of positioning cannot be effectively guaranteed.

The advantage of WiFi positioning is mainly that the deployment of WiFi is wide, and WiFi has the largest deployment amount in various indoor occasions as the most important wireless transmission means at present, so that WiFi is ubiquitous, and in occasions with low precision requirements, the WiFi positioning function can be opened by assuming positioning engine service after the construction of a WiFi data transmission network is finished. The second advantage of WiFi positioning is low cost, the price of the WiFi chip module 2018 is reduced to about 10 yuan, the price of the WiFi base station is within hundred yuan, and the functions of data transmission and positioning can be achieved, so that the requirement of low-cost large-scale expansion can be met. A third advantage of WiFi positioning is that a cell phone terminal can be utilized, omitting the cost of terminal deployment. Therefore, wiFi positioning is the least costly of the several indoor positioning schemes described above. The Android 9.0 version already supports WiFi positioning at present, but position data of WiFi positioning comes from an unknown website, data of a WiFi base station is collected by the unknown website through a mobile terminal when a user starts WiFi auxiliary positioning, and the application already relates to deep security.

In view of the above-mentioned, it is desirable,

the GNSS signals are not available indoors, and the network and the base station are adopted to forward the GNSS signals, so that the network transmission time is uncontrollable due to network jitter and congestion, and the GNSS signals are not available as well; the A-GPS technology combined with the satellite positioning technology and the base station auxiliary positioning technology has too high dependence on GNSS, and when no satellite signal exists, the A-GPS is actually degenerated into base station positioning (LBS positioning), and the positioning precision can not meet the general application requirements far; the existing local positioning technology mostly puts new requirements on infrastructure, and has single action and high networking cost, so the feasibility is poor.

However, there is an increasing demand for indoor positioning, and the demand is increasing. Providing high quality location services must provide the following requirements:

1) Providing high-precision and high-reliability indoor positioning signals;

2) The deployment is easy, the networking cost is low, and the trans-regional seamless service can be provided;

3) Easy to operate and use, does not increase customer's burden;

4) Based on open public service, fully utilizing social public resources, not depending on monopoly resources, and not being pinched and killed by benefit groups obtained by monopoly resources;

5) The indoor map and the position information service with high quality and high precision.

For this reason we have developed a positioning method and system for indoor use which has the advantages described above and which overcomes the above-mentioned drawbacks of the prior art, serving the need of people for high-precision location services.

Disclosure of Invention

The invention aims to solve the problems that the wide area positioning technology is difficult to realize indoor high-precision positioning and the local area positioning technology is difficult to provide wide area seamless service. In order to solve the problems, the invention discloses a positioning method and a positioning system which can be used indoors and meet the requirements of wide-area and high-precision indoor positioning.

The indoor positioning method is characterized in that the method uses a mobile terminal, an LBS base station, a WPS base station and a positioning service center, and adopts four messages: the method comprises the steps of adopting an indirect measurement method to indirectly measure the coordinates of an LBS base station by utilizing the positioning of an outdoor mobile terminal in a first calibration process; and in the second step, the coordinates of the indoor target 'mobile terminal' are measured by using the known coordinates of the LBS base station.

The calibration process comprises the steps that the mobile terminal receives satellite positioning signals to position itself, differential positioning is started under the condition that high-precision positioning can be carried out under the assistance of differential signals, accurate positioning is carried out by itself, and the mobile terminal calibrates the clock of the mobile terminal by using the clock of the GNSS.

The positioning request message and the positioning message are combined in a return way in the calibration process, and the method comprises the following steps:

s102-302: the mobile terminal selects an LBS base station and sends a positioning request message and a positioning message Wen Huiwen to the LBS base station;

s103-304: the LBS base station sends a positioning request message and a positioning message to a positioning service center;

s104-306: judging whether the mobile terminal is registered, executing the steps to 109-311 if the mobile terminal is registered, and executing the steps to 105-309 if the mobile terminal is not registered;

S105-309: the positioning service center performs authentication and registration;

s106-307: judging whether the registration is successful;

s107-308: failing registration and giving up;

s108-305: the registration is successful, the positioning service center starts a service process and sends a positioning message to the LBS base station;

s109-311: the location service center calculates LBS base station coordinates according to the location message of the mobile terminal and the GNSS coordinates of the mobile terminal;

s110-312: the positioning service center sends a positioning message to the LBS base station;

s111-310: the LBS base station receives the positioning message of the positioning service center and forwards the positioning message to the mobile terminal;

s112-303: the mobile terminal receives the positioning message and the differential message and optimizes the local coordinate calculation;

s113: steps S102-302 are repeated to continuously update the coordinate information of the LBS base station coordinates.

The positioning request message and the positioning message are not combined in the calibration process, and the method comprises the following steps: s102-302: the mobile terminal selects an LBS base station and sends a positioning request message or a positioning report Wen Huiwen to the LBS base station;

s103-304: the LBS base station sends a positioning request message or a positioning message to a positioning service center;

s104-306: the positioning service center judges whether to position the request message or position the message Wen Huiwen;

s105-309: if the message is a positioning request message, the positioning service center performs authentication and registration;

S106-307: judging whether the registration is successful;

s107-308: failing registration and giving up;

s109-311: if the location message is a location message, the location service center calculates LBS base station coordinates according to the location message of the mobile terminal and GNSS coordinates of the mobile terminal;

The positioning request message and the positioning message return message are not combined in the positioning process, and the method comprises the following steps:

1. the mobile terminal sends a positioning request message to the LBS base station;

the LBS base station transmits the positioning request message to a positioning service center;

3.1 the location services center authenticates the mobile terminal 1101 and fails to reject service;

3.2 the mobile terminal fails in the authentication process and cannot use the service of the positioning service center;

4. the mobile terminal successfully authenticates, the positioning service center provides service and sends a positioning message to the LBS base station;

5.1 The LBS base station forwards the positioning message to the mobile terminal;

5.2 The LBS base station forwards the positioning message to the WPS base station;

6.1, the mobile terminal returns a positioning message to the LBS base station;

6.2 The WPS base station returns a positioning message to the LBS base station;

the LBS base station forwards the positioning message return message of the WPS base station and the positioning message return message of the mobile terminal to a positioning service center;

8. the positioning service center sends a differential message to the LBS base station;

and 9, the LBS base station transmits the differential message to the mobile terminal.

The positioning process comprises the following steps:

s201-401: the mobile terminal enters a room and cannot receive satellite positioning signals, and an indoor mode is started;

s202-402: the mobile terminal selects an LBS base station to send a positioning request message or a positioning message Wen Huiwen to the LBS base station;

s203-403: the LBS base station sends a positioning request message or a positioning message return message to a positioning service center;

s204-410: the positioning service center judges whether to position the request message or position the message Wen Huiwen;

s205-407: if the message is a positioning request message, the positioning service center performs authentication and registration;

s206-408: judging whether the registration is successful;

s207-409: failing registration and giving up;

s208-406: the registration is successful, the positioning service center starts a service process and sends a positioning message to the LBS base station;

S209-414: if the mobile terminal is in the positioning message, the positioning service center calculates the coordinates of the mobile terminal according to the positioning message of the mobile terminal;

s210-415: the positioning service center sends a positioning message and a differential message to the LBS base station;

s211-413: the LBS base station receives the positioning message and the differential message of the positioning service center and forwards the positioning message and the differential message to the mobile terminal and the WPS base station;

s212-412: the WPS base station receives the positioning message, records the receiving time and sends the positioning message back to the LBS base station; the WPS receives the differential message and gives up.

S213-411: the LBS base station forwards the positioning message sent by the WPS base station to a positioning service center;

s214-404: the mobile terminal receives the positioning message and the differential message;

s214-402: the mobile terminal adjusts the local map coordinates according to the difference;

s215-403: the mobile terminal receives the positioning message, records the receiving time, sends the positioning message back to the LBS base station,

s216: steps S203-403 are repeated to continuously update the mobile terminal coordinates.

According to another embodiment, the invention provides a positioning method usable indoors, characterized in that it employs an indirect measurement method comprising two stages: stage 1, outdoor calibration stage, which includes S201, using GNSS signal to obtain mobile terminal coordinates, S202, using mobile terminal coordinates to determine LBS base station coordinates outdoors, S203, repeating S201 and S202 several times; stage 2, indoor positioning stage, including S204, using the obtained LBS base station coordinates to determine indoor mobile terminal coordinates.

Differential information is generated by adopting a time differential positioning method, and a WPS base station with basically unchanged position coordinates with an LBS base station is adopted in the process.

In the 2 nd stage, the positioning service center sends out a positioning message MSG1 with a time stamp at the time T0, reaches the LBS base station at the time T1 through a plurality of internet routers, is forwarded by the LBS base station, the mobile terminal receives the MSG1 at the time T3, and the WPS base station receives a copy MSG1 of the positioning message MSG1 at the time T2 ^* From this, the pseudo-range Δt13 from the mobile terminal to the LBS base station can be calculated, the value range is constantly equal to or greater than 0, and the mobile terminal coordinates can be further calculated by using the value.

The method further comprises the step of the mobile terminal scanning surrounding LBS base stations before the 1 st stage, specifically: the mobile terminal scans surrounding LBS base stations to form a list, the mobile terminal selects one base station to establish connection, after the connection is successful, the mobile terminal sends a positioning request message to a positioning service center through the LBS base station, the positioning service center starts a service process after passing authentication, and sends a positioning message and a differential message to the LBS base station, the mobile terminal interacts with the LBS base station for one or more times to indicate that the connection is successfully established, and then the mobile terminal selects the next LBS base station to repeat the steps to realize accurate positioning.

In order to obtain the accurate coordinates of the LBS base station, the four GNSS systems currently running on-orbit: GPS, BDS, GLONASS, GALILEO, firstly obtaining a time seed of a satellite system, then calibrating by using clock signals of other satellite systems to obtain clock signals, calculating position coordinates by using the clock signals, and finally repeating the steps for several times to calibrate the coordinates of the mobile terminal by using a clock deviation mean value and a position deviation mean value.

The invention discloses a positioning system and a positioning method which can be used indoors, which are obviously different from LBS positioning technology and RSSI/Rx positioning technology adopted by the current operators,

1) The LBS positioning technology takes the coverage area of a base station as the coordinates of the mobile terminal, and the precision is about 100 meters;

2) The signal intensity attenuation and the distance of the RSSI/Rx method have nonlinear relation, the signal intensity attenuation is unpredictable after encountering walls and the like, meanwhile, the direction of a non-omni-directional antenna has directivity, the angle between the antenna and the antenna also causes irregular attenuation of the signal intensity, and the data generated by the RSSI/Rx method has uncertainty;

3) The electromagnetic environment in the indoor environment is more complex, and the electromagnetic environment also has the multipath problem and the reflection diffraction interference problem, but the invention relies on GPRS and 2/3/4/5G data communication technology, and the problem is solved and widely applied by equipment manufacturers.

The invention discloses a positioning system and a positioning method which can be used indoors, which are different from a GNSS positioning mode in that:

1) The special positioning base station WPS base station is mainly deployed indoors, the WPS base station and the mobile terminal cannot use GNSS positioning signals, the LBS base station uses an operator communication base station to send positioning messages to receive positioning messages Wen Huiwen, and the LBS base station is provided with positioning systems (mainly used for time service, whole network synchronous clock) such as GPS/BDS and the like, but does not provide services for a third party. Therefore, the positioning signal sources are different, the clock synchronization modes are different, the methods for determining the position coordinates of the base station are different, the modes for generating differential data are different, the generated differential signals are different, and the modes for using the differential data are also different.

2) The difference of the positioning messages is that the time of the traditional GNSS navigation message is longer, for example, 750 seconds are needed for receiving a complete navigation message by a GPS, and the sending time of the positioning message is much shorter than that of the positioning message of the invention, and the positioning service center of the invention generally sends a group of at least 3 positioning messages at a time, for example, the positioning message is sent by using a TD-LTE base station, and the positioning message is compressed in a subframe, namely, the positioning message is sent within 1 ms.

3) The differential messages are different, the differential protocol message sent by the traditional differential base station is correction quantity of GNSS signals, and the differential message sent by the location service center is coordinate correction parameter calculated by the location service center.

4) The differential station is different from a differential system, a local reference station and a wide area reference station exist in a traditional satellite positioning differential positioning reference station, the differential reference station receives GNSS signals, differential information is calculated to be broadcasted to the periphery, the GNSS differential reference station is a special base station, the base station is a local base station, and the differential positioning system is formed by an LBS base station for providing data access service by an operator, a WPS base station of the special positioning base station and a positioning service center, and the differential positioning system is basically different from the differential positioning base station and the positioning service center.

5) The difference between the open-loop information transmission of the GNSS and the closed-loop information system of the invention is that the traditional differential base station and the mobile terminal are not connected with the positioning satellite, the information is open-loop, and the design of the GNSS system determines that the information of the GNSS must be open-loop; the differential system of the invention comprises a complete data closed loop formed by the mobile terminal, the LBS base station, the WPS base station and the positioning service center, and the closed loop has the advantage of high information security, so that the flow process of a user can be completely monitored, the system can be used only by registering and authenticating the user in a closed network environment, the behavior of the user is limited, and the potential safety hazard faced by high-precision positioning is avoided.

6) The positioning frequency is fixed and the positioning frequency can be set, which can be quite different. The invention transmits a positioning message, and the frequency for generating the differential message can be set according to the requirement, for example, in order to realize high-precision positioning in a short distance or adopt ten times of positioning message transmission per second.

7) The system for transmitting and receiving signals is different, the GPS, BDS, GALILEO system adopts a CDMA mode, the GLONASS adopts an FDMA mode (the FDMA mode of the GLONASS is evolving to the CDMA mode), all satellites for positioning by the GNSS system transmit positioning signals in a strict synchronization mode, a pseudo range is calculated according to the time difference of a mobile terminal receiving positioning messages, the invention is neither CDMA nor FDMA, and the time of transmitting the messages by an LBS base station does not need strict time synchronization.

8) The manner of implementing the positioning is different. The invention actively scans surrounding LBS base stations by the mobile terminal, distinguishes the base stations providing service according to LAC, CID of an operator and SSID or MAC of WiFi base stations, and the number of the satellites currently in orbit is 41 Beidou satellites, 32 GPS satellites, 30 GLONASS satellites, 30 GAOLEO satellites, about 150 GAOLEO satellites, and the number of LBS base stations and WPS base stations is much larger than the number of satellites.

9) In the GNSS positioning process, a mobile terminal at least needs to receive signals of 4 compatible satellites to position, and in a many-to-one mode, a positioning message sent by an LBS base station is received by the mobile terminal and at least one special positioning base station WPS base station, and the method is in a one-to-many mode. The GNSS positioning coordinate calculation is completed in the mobile terminal, and the positioning coordinate calculation is completed in the positioning service center.

10 Different ways of calculating the pseudo range, the GNSS must transmit positioning signals in strict time synchronization to all satellites, and the error of the clock is directly reflected to the error of calculating the pseudo range. The transmission time errors from the positioning service center to the LBS base station are all counteracted, and the error factors are only related to clocks of the mobile terminal and the WPS base station, namely, the time errors of the mobile terminal and the WPS base station determine the positioning accuracy of the invention, and the error factors are greatly reduced compared with those of a GNSS system.

Drawings

The present specification includes the accompanying drawings to clearly illustrate the preferred embodiments of the present invention, in which:

fig. 1 is a schematic diagram illustrating a system configuration of a positioning system usable indoors according to an embodiment of the present invention.

Fig. 2 is a schematic diagram illustrating positioning phase division of a positioning system usable indoors according to an embodiment of the invention.

Fig. 3 is a schematic diagram illustrating a first stage calibration process flow for a positioning system usable indoors according to an embodiment of the invention.

FIG. 4 is a schematic diagram illustrating a second stage positioning process flow for a positioning system that may be used indoors according to an embodiment of the invention.

Fig. 5 is a schematic diagram of a differential calculation method for calculating a pseudo range that can be used in an indoor positioning method according to an embodiment of the present invention.

Fig. 6 is a schematic diagram of a process in which a mobile terminal searches for a surrounding LBS base station, which can be used in an indoor positioning method according to an embodiment of the present invention.

Fig. 7 is a flowchart of mobile terminal coordinates and time seeds calculated by GNSS optimization for a mobile terminal usable in an indoor positioning method according to an embodiment of the present invention.

Fig. 8 is a schematic diagram of a constitution of a mobile terminal usable in an indoor positioning method according to an embodiment of the present invention.

Fig. 9 is a schematic diagram of the constitution of a WPS base station usable in an indoor positioning method according to an embodiment of the present invention.

Fig. 10 is a schematic diagram of a location service center structure that may be used in an indoor location method according to an embodiment of the present invention.

Fig. 11 is an interaction diagram of a message passing process between four constituent parts that can be used in an indoor positioning method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Detailed Description

The following description of the present invention will provide specific embodiments, and it should be noted that the specific embodiments described in this specification are only intended to illustrate the gist of the present invention, and do not limit the scope of the present invention.

In a preferred embodiment of the present invention, a positioning system for indoor use is disclosed, which is mainly composed of the following four parts, as shown in fig. 1: the mobile terminal 101, the LBS base station 102, the WPS base station 103, the location service center 104, the mobile terminal 101 and the LBS base station 102 may communicate with each other, the LBS base station 102 and the location service center 104 may communicate with each other, and the WPS base station 103 and the LBS base station 102 may communicate with each other. The mobile terminal 101 is a user handheld terminal, the mobile terminal 101 is connected to the location service center 104 through the LBS base station 102, and the WPS base station 103 is connected to the location service center 104 through the LBS base station 102.

The mobile terminal 101 sends a positioning request message and a positioning message back to the LBS base station 102, receives the positioning message and the differential message forwarded by the LBS base station 102, and can utilize GNSS signals to realize positioning and clock calibration under the outdoor condition of the mobile terminal 101.

The LBS base station 102 is used for forwarding a positioning request message and a positioning message of the mobile terminal 101 to the positioning service center 104, and forwarding a positioning message and a differential message of the positioning service center 104 to the mobile terminal 101; the LBS base station 102 transmits the positioning message to the WPS base station 103, and the LBS base station 102 transmits the positioning message of the WPS base station back to the positioning service center 104; LBS base station 102 includes base stations that provide data services for each large operator that provides service access for mobile terminal 101, such as 2/3/4/5G service base stations, wiFi base stations, wimax base stations, etc. operated by the operator.

The WPS base station 103 receives the positioning message sent by the positioning service center 104, and sends a positioning message reply to the positioning service center 104.

WPS base station 103 (WPS, wide band Positioning Station) is a dedicated broadband positioning serving base station developed by the present invention. The WPS base station may be designed and implemented by a software-defined method, and has a relatively wide receiving spectrum, and is capable of receiving data messages of all signal frequency bands including, but not limited to, GPRS, 2-5G, wiMAXs, zigbee, and the like. The WPS base station 103 has functions of synchronizing a clock, receiving a positioning message, transmitting a time for receiving the positioning message by a positioning message return message, and receiving and broadcasting a ranging message.

The role of the location service center 104 includes storing the location coordinates of the LBS base station 102, providing location services and location coordinate calculation services. Storing LBS base station 102 coordinates is implemented by a database module; the positioning service center 104 providing positioning services includes providing a positioning message and a differential message to the mobile terminal 101 in response to a positioning request message of the mobile terminal 101; the location service center 104 provides a location coordinate calculation service by a location coordinate calculation module, and obtains the coordinates of the LBS base station and the differential data of the mobile terminal 101 by calculating a location report Wen Huiwen.

The invention discloses a positioning system and a positioning method which can be used indoors, wherein 4 messages of positioning request messages, positioning message return messages and differential messages are defined and used.

The positioning request message is used for registering and authenticating the mobile terminal to the positioning service center, establishing connection, and establishing a process for serving the mobile terminal by the positioning service center.

The positioning message is used for measuring the pseudo range from the mobile terminal to the LBS base station, the positioning message is sent by the positioning service center, the LBS base station forwards, the WPS base station and the mobile terminal receive the positioning message, and the WPS base station and the mobile terminal send a positioning message return message after receiving the positioning message.

The positioning message Wen Huiwen is sent back by the WPS base station and the mobile terminal after receiving the positioning message, and is forwarded to the positioning service center by the LBS base station. The time of the WPS base station and the mobile terminal receiving the positioning message has small time difference, and the WPS base station and the mobile terminal record the time of the received message, utilize the positioning message to return the message and forward the message to the positioning service center by the LBS base station. And the positioning service center completes pseudo-range calculation and positioning calculation according to the time recorded by the positioning message.

The differential message is sent by the positioning service center and is forwarded to the mobile terminal through the LBS base station. In an embodiment, the differential message may be combined into the positioning message.

In order to eliminate the positioning accuracy errors of the mobile terminal caused by satellite clock errors, ephemeris errors, ionosphere errors, troposphere errors and propagation delay errors, the conventional GPS difference generates difference information by a precisely positioned difference station and sends the difference information to a mobile device of a client. The target space of the invention is indoors, the mobile terminal can not receive GNSS signals indoors, and the differential information of the differential station like GPS or BDS can not be used for correcting the deviation.

Technical details of the mobile terminal 101, lbs base station 102, wps base station 103, and location service center 104 included in the indoor location system according to the present invention will be described below.

Mobile terminal 101:

the user hand-held terminal is generally a smart phone used by a user, and can also be special equipment, such as special indoor mapping equipment and mobile coordinate calibration equipment which are custom developed and developed by the company.

The mobile terminal has the capability of receiving mobile internet data messages and transmitting data messages.

The mobile terminal has the capability of receiving satellite positioning signals, and can utilize GNSS signals to realize positioning and clock calibration under outdoor conditions. The mobile terminal is connected with the location service center through the LBS base station.

The mobile terminal has two working modes, namely a calibration mode (working mode 1) and a positioning mode (working mode 2).

Operating mode 1, calibration mode (or outdoor mode). The mobile terminal can acquire the coordinates of the mobile terminal and correct the clock thereof by using the GNSS signals outdoors, and further measure the coordinates of the LBS base station and synchronize the clock of the WBS base station by using the GNSS coordinates and the clock.

As shown in fig. 3, the coordinates of the LBS base station are measured, the mobile terminal is required to start the GNSS function in the outdoor environment, obtain the GNSS coordinates of the mobile terminal, send the GNSS coordinates to the LBS base station through the positioning report Wen Huiwen and forward the GNSS coordinates to the positioning service center by the LBS base station, and the positioning service center calculates the coordinates of the LBS base station according to the positioning message.

And 2, a positioning mode (or an indoor mode), wherein the mobile terminal is positioned indoors by using the LBS base station coordinates. As shown in fig. 4, the mobile terminal is successfully registered in the location service center, and the mobile terminal and the location service center can perform message interaction. Firstly, starting a working mode 2 by a mobile terminal, searching and selecting an LBS base station, sending a positioning request message through the LBS base station, and forwarding the positioning request message to a positioning service center by the LBS base station; then, after verifying the authority, the positioning service center starts a service process (a process or a thread is described by a process in the scope of the invention) and sends out a positioning message, and the LBS base station forwards the positioning message to the mobile terminal and the WPS base station; then the WPS base station and the mobile terminal send the time for receiving the positioning message back to the positioning service center by using the positioning message; and finally, the positioning service center calculates the position coordinates of the mobile terminal, sends a differential message to be forwarded to the mobile terminal by the LBS base station, and corrects the position coordinates of the mobile terminal according to the differential message.

The serving base station:

the system comprises LBS base stations for providing data service for each large operator providing service access for the mobile terminal and special WPS base stations for positioning service, and can also adopt LoRa base stations, bluetooth base stations, UWB base stations and ZigBee base stations which have cooperative relationship and can realize data communication as the LBS base stations and/or the WPS base stations. The service base station is connected with the mobile terminal and the positioning service center through a network.

LBS base station 102: LBS base stations are mainly base stations for operators to provide data communication access services and other types of base stations with cooperative relations, such as LoRa base stations and the like.

When the mobile terminal works in the working mode 1, the LBS base station receives a positioning request message and a positioning message return message of the mobile terminal and forwards the positioning request message and the positioning message return message to a positioning service center; the positioning service center responds to the positioning request message and the positioning message of the mobile terminal to send out a positioning message and a differential message, and forwards the positioning message and the differential message to the mobile terminal through the LBS base station.

When the mobile terminal works in the working mode 2, the LBS base station receives a positioning request message and a positioning message return message of the mobile terminal and forwards the positioning request message and the positioning message return message to a positioning service center; the WPS base station receives the positioning message and transmits a positioning message return message to be forwarded to the positioning service center by the LBS base station, and the positioning service center responds to the positioning request message and the positioning message return message of the mobile terminal to transmit a positioning message and a differential message, and forwards the large mobile terminal through the LBS base station.

WPS base station 103:

the WPS base station aims to detect the time delay of network transmission of a positioning message and eliminate the uncertainty of network transmission time caused by network jitter and blocking. The WPS base station may be designed and implemented by a software-defined method, and has a relatively wide receiving spectrum, and is capable of receiving data messages of all signal frequency bands including, but not limited to, GPRS, 2-5G, wiMAXs, zigbee, and the like. The WPS base station has the functions of synchronizing a clock, receiving a positioning message, transmitting time for receiving the positioning message through the positioning message in a back-messaging manner, and receiving and broadcasting a ranging message. Other types of base stations with cooperative relationships may also be used as WPS base stations, such as a LoRa base station, etc.

The WPS base station receives the positioning message of the positioning service center, records the time of message receiving, sends the positioning message back to the positioning service center, and is used for calculating the pseudo range from the mobile terminal to the LBS base station by the positioning service center.

Location service center 104:

the main functions of the positioning service center are as follows: responding to a service request of the mobile terminal, sending a positioning message and/or a differential message to an LBS base station, and forwarding the positioning message and/or the differential message to the mobile terminal and the WPS base station by the LBS base station; and according to the positioning message replied by the mobile terminal and the WPS base station, the pseudo range from the mobile terminal to the LBS base station is returned, and the coordinates of the LBS base station and the coordinates of the mobile terminal are further calculated.

The location service center is responsible for storing the position coordinates of the LBS base station and continuously optimizing and calculating LBS coordinate data through historical data.

Further details of the mobile terminal 101, lbs base station 102, wps base station 103, and location service center 104 in the preferred embodiment of the present invention will be described in further detail below.

Mobile terminal structure

The mobile terminal is made up of hardware and/or software parts described below, as shown in fig. 8.

1. Satellite signal receiving hardware section 801

The satellite positioning signal receiving chip and the satellite signal receiving antenna form a satellite positioning signal receiving antenna which can receive positioning signals of GNSS (global satellite positioning system) and convert electromagnetic waves into calculable digital signals.

Multiple satellite positioning chips may be included, such as: BDS, GPS, GLONASS, GALILEO system. Standard satellite positioning chips and antennas, provided by chip suppliers, provide standard service interfaces.

2. Satellite message receiving module 805

Each large mobile terminal manufacturer has built in a positioning chip of a GNSS system such as BDS in its mobile terminal product, which constitutes a basic platform of GNSS positioning hardware. In general, the software can directly use the positioning chip to give position coordinates, speed and altitude information.

In the application of the present invention, the original data acquired by the module 801, such as the original message of the positioning protocol NMEA0183 used by the GPS, is needed, and the satellite message receiving module re-calculates the position information by the message calculating module 811 after receiving the original message.

3. Satellite clock calibration module 806

The satellite broadcast signal has time service function, and the satellite clock calibration module corrects the local clock of the received satellite signal, so that a relatively accurate time seed can be obtained.

The present invention performs calibration by the GNSS system multisystem in the satellite clock calibration module 806, which may result in high quality time seeds, clock calibration methods and processes, as shown in FIG. 7.

WiFi signaling hardware section 802

The WiFi chip and the WiFi chip antenna constitute a WiFi signal transceiving hardware section 802.

The WiFi chip is used in the mobile terminal almost without exception, and the WiFi chip is utilized to transmit and receive the positioning request message, the positioning message return message and the differential message.

The transmit power of the WiFi chip is defined and set by the channel selection and control module 804.

5. Telecommunication portion 803

The GPRS, 2G/3G/4G/5G chip antenna forms the telecommunications portion 803. The current mobile terminals basically open GPRS, 2G/3G/4G services, and 5G services have begun to be tried on worldwide. The invention is based on GPRS and 2-5G wireless internet data service development, and receives and transmits messages based on mobile internet data service, wherein the messages comprise positioning request messages, positioning message return messages and differential messages.

In the same time and space, GPRS, 2G/3G/4G and future 5G data service base stations of each operator can realize communication with a far end.

With the telecommunications data traffic available as described above, the channel selection and control module 804 defines and sets up to select the operator and traffic pattern to use.

6. Channel selection and control module 804

The function of the channel selection and control module 804 is to select an LBS base station, which may be implemented in a preferred manner by the procedure shown in fig. 6.

The mobile terminal searches available LBS base stations around, marks the available base stations, and selects the available base stations according to a preferred strategy to realize message interaction with the positioning service center.

7. Message receiving module 807

The message receiving module 807 is a waiting process, receives the message from the LBS base station, and forwards the message to the message optimizing module 809.

8. Message sending module 808

The message sending module 808 is connected to the channel selection and control module 804, and establishes a network connection with a remote server to form a data communication link. And the mobile terminal sends a positioning request message and a positioning message back to the LBS base station.

9. Message optimization module 809

The message optimizing module 809 optimizes and cleans the received messages from the GNSS and/or LBS base station, and retains the available high quality messages, 1) sends the messages to the message resolving module 811 for position coordinate resolving, and 2) sends the messages to the differential module 812 for differential coordinate computing.

10. Transmission control module 810

The transmission control module loads the service rules and policies of the mobile terminal, such as the interval of search time of the LBS base station of the mobile terminal.

The transmission control module 810 invokes the positioning request message generation module 814 to generate a positioning request message, which is forwarded to the message sending module 808, and invokes the positioning message reply generation module 813 to generate a positioning message reply, which is forwarded to the message sending module 808. In an embodiment, the positioning request message of the mobile terminal may be combined with the positioning message.

11. Message resolving module 811

In the working mode 1, the message resolving module 811 is used for resolving the positioning message sent by the positioning service center, the differential message forwarded by the GNSS satellite positioning message and the LBS base station, and the differential data generated by the differential module 812, and the message resolving module is used for calculating the coordinates of the LBS base station according to the positioning message return message of the mobile terminal and the GNSS coordinates of the mobile terminal.

In the working mode 2, the message resolving module 811 is used for resolving the positioning message sent by the positioning service center and forwarded by the LBS base station, the differential message and the differential data generated by the differential module 812, and calculating to obtain the coordinates of the mobile terminal.

The satellite positioning message is a satellite positioning message original data, such as an NMEA0183 protocol original message, received by the satellite message receiving module 805. The LBS base station forwards the positioning message and the differential message, and the positioning message and the differential message are received by the message receiving module 807, and the coordinate calculation is completed by the message optimizing module 809, the differential module 812 and the message resolving module 811. In a specific embodiment, the positioning message and the differential message may be combined into one message.

12. Differential module 812

The invention serves indoor mobile terminals, the indoor cannot receive GNSS signals, and differential information similar to GPS or BDS differential stations cannot be used. The invention adopts innovative time difference, and completely eliminates clock errors caused by network jitter and blockage. The implementation process is as shown in fig. 5:

the positioning message sent by the positioning service center 505 during T0 seconds passes through the complex internet 504, and arrives at the LBS base station 503 at the time T1, the LBS base station 503 forwards the positioning message, and the mobile terminal 501 receives the positioning message at the time T3 and the WPS base station 502 at the time T2. The "pseudo" distance of the WPS base station 502 to the LBS base station 503 is a constant, the propagation time of the positioning service center 505 to the LBS base station is easily obtained, and the pseudo range of the mobile terminal 501 to the LBS base station 503 is further calculated.

The pseudo-range measurement accuracy of the invention is only related to the time measurement accuracy.

13. Positioning message return generation module 813

The positioning message callback generating module 813 is used for calling the clock calibration module 806 after receiving the positioning message of the positioning service center, recording the time of message reception, namely, the time T3 in fig. 5, and sending the time to the positioning service center in the form of positioning message callback.

14. Location request message generation module 814

After the mobile terminal is initialized, the mobile terminal needs to register with a positioning service center, the mobile terminal sends a positioning request message to an LBS base station, the LBS base station forwards the positioning request message to the positioning service center, and the positioning service center establishes a process for serving the mobile terminal. The positioning request message realizes the service registration process.

In the embodiment, the positioning message return message and the positioning request message can be combined into one message.

(II) construction of serving base station

LBS base station constitution

The LBS base station is mainly a communication base station of a telecom operator as a public infrastructure, part of WiMAXs base stations and WiFi base stations are also carrier-class broadband base stations deployed by operators, and the base station structure is provided by the design of equipment manufacturers. The invention is used as only one available data transmission device.

WPS base station constitution

The special positioning base station 'WPS base station' is specially designed and customized based on the WiFi positioning base station, and the structure can be referred to as figure 9. Hereinafter, preferred embodiments of the respective parts of the WPS base station will be specifically described.

1. Positioning message receiving module 901

The positioning message receiving module 901 of the WPS base station is a waiting module, which receives the positioning message sent by the LBS base station, calls the clock calibration module 904 to obtain time, calls the positioning message reply generating module 903, and generates a positioning message reply.

2. Message sending module 902

The task of the message sending module is to send the positioning message back to the LBS base station, and the positioning message is forwarded to the positioning service center by the LBS base station.

3. Location report Wen Huiwen module 903

The positioning message Wen Huiwen module 903 receives the positioning message received by the positioning message receiving module 901, calls the clock calibration module 904, records accurate receiving time, generates a positioning message return message and forwards the positioning message return message to the positioning service center.

4. Clock calibration module 904

Calibration is performed with the mobile terminal clock by clock calibration 904. The relative accuracy of the mobile terminal and the WPS base station clock is the basis of the positioning accuracy.

(III) positioning service center

The function of the positioning service center is to receive the positioning request message and the positioning message return message of the mobile terminal and the positioning message Wen Huiwen of the WPS base station, authenticate and service register the mobile terminal, establish a service process for the mobile terminal according to the positioning request message of the mobile terminal, calculate the positioning message return message of the mobile terminal and the positioning message return message of the WPS base station, and obtain the pseudo range from the mobile terminal to the WPS base station.

As shown in fig. 10, the location service center includes a message sending module 1001, a message receiving module 1002, an authentication module 1003, a clock calibration module 1004, a location service module 1005, a location calculation service module 1006, a location message generating module 1007, a differential message generating module 1008, a differential calculation module 1009, and a database module 1010. The portions of the location service center of the present invention are described in detail with reference to fig. 10.

1. Message sending module 1001

The location service center responds to the location request and the location message return of the mobile terminal, the location service module 1005 calls the location message generation module 1007 and the differential message generation module 1008 to generate a location message and a differential message, and sends the location message and the differential message to the LBS base station through the message sending module 1001, so that the LBS base station forwards the location message and the differential message.

2. Message receiving module 1002

The message receiving module 1002 receives the positioning request message forwarded by the LBS base station, invokes the authentication module 1003 to authenticate the use authority of the mobile terminal, the mobile terminal passes the authentication, the positioning service module 1005 does not pass the authentication, and the message receiving module refuses to receive the service request of the mobile terminal.

The message receiving module 1002 receives the positioning message Wen Huiwen forwarded by the LBS base station, and forwards the positioning message receipt calculated by the positioning service module 1005.

3. Authentication module 1003

The message receiving module 1002 receives the positioning request message forwarded by the LBS base station, the authentication module 1003 authenticates the use authority of the mobile terminal, the authentication module 1003 inquires the database module 1010 to determine whether the mobile terminal has the right to use the service, and the authentication module 1003 issues a pass to the mobile terminal through authentication.

4. Clock calibration module 1004

The foregoing has deduced that the positioning error is only related to the clock measurement accuracy of WPS base stations and mobile terminals, and not related to the time error of the positioning service center. The clock calibration may be used here as a network time service. The clock calibration module 1004 obtains a high-precision time seed through an external GNSS time service system, and the positioning message generation module 307 and the differential message generation module 308 need the time seed as the T0 time in fig. 5.

5. Location services module 1005

The location services module 1005 is responsible for managing service processes or service threads. After the location request message is authenticated by the authentication module 1003, the location service module 1005 starts a service process to provide services for the mobile terminal. The service process started by the location service module 1005 calls the differential calculation module 1009 to calculate a location message reply sent by the mobile terminal and a location message reply sent by the WPS base station, so as to obtain a pseudo range from the mobile terminal to the LBS base station, and the location service module 1005 calls the location calculation service module 1006 to calculate the location coordinate of the mobile terminal.

The location service module 1005 invokes the message sending module 1001 to send a location packet to the LBS base station at a certain time interval, for example, 0.5 seconds, and the location packet is forwarded to the mobile terminal and the WPS base station by the LBS base station.

6. Location calculation service module 1006

As described above, the coordinate calculation of the present invention is divided into two stages, the first stage calculates the coordinates of the LBS base station and the second stage calculates the coordinates of the mobile terminal according to the coordinates of the LBS base station. The location calculation service module 1006 functions to calculate the coordinates of the LBS base station and the mobile terminal.

Stage 1 calculates LBS base station coordinates. Stage 1 requires the determination of LBS base station coordinates with the mobile terminal, which must be able to receive GNSS signals outdoors. The process is shown in fig. 3.

And 2. Calculating the coordinates of the mobile terminal. The mobile terminal cannot use GNSS signals indoors and calculates the coordinates of the mobile terminal using the coordinates of the known LBS base station. The process is shown in fig. 4.

7. Location message generation module 1007

After the mobile terminal location request message is authenticated by the authentication module 1003, the location service module 1005 starts responding to the location request message. The location service module 1005 invokes the location message generation module 1007 to generate a location message.

8. Differential message generation module 308

The differential message is used for transmitting the calibration deviation of the position coordinates. The position calculation service module 1006 and the difference calculation module 1009 calculate the coordinate deviation of the mobile terminal, and the difference message is packed into a difference message by the difference message generation module 1008 and sent to the mobile terminal to correct the map information of the mobile terminal.

The embodiment can combine the differential messages into the positioning message and send the positioning message to the mobile terminal.

9. Differential calculation module 1009

The function of the differential computation module 1009 is to compute the pseudorange of the mobile terminal to the LBS base station.

As shown in fig. 5, the positioning message feedback sent by the mobile terminal and the positioning message feedback sent by the WPS base station record a time stamp T0 of the positioning message sent by the positioning service center and time T1 and time T2 when the mobile terminal and the WPS base station receive the positioning message, wherein the time difference between the time T1 and the time T2 is the difference between pseudo ranges from the mobile terminal and the WPS base station to the LBS base station. The higher the accuracy of the T1 and T2 times, the higher the accuracy of the pseudorange measurements.

The accuracy of the clocks of the WPS base station and the mobile terminal is a key factor of pseudo-range measurement of the invention. When the WPS base station and the mobile terminal clock are not synchronized, T1 and T2 cannot directly calculate the pseudo range.

10. Database module 1010

The database module 1010 functions to store the coordinate data of the LBS base station and the temporal data for pseudo-range and coordinate calculations.

Hereinafter, a positioning method usable indoors according to a preferred embodiment of the present invention will be described in detail.

Another preferred embodiment of the present invention discloses a positioning method for indoor use, wherein the method adopts an indirect measurement method to realize indoor positioning, and the method comprises two stages, as shown in fig. 2: a 1 st stage, an outdoor calibration stage, wherein S201, mobile terminal coordinates are firstly obtained by utilizing the characteristic that GNSS signals can be used outdoors of a mobile terminal, S202, coordinates of an LBS base station are measured by utilizing the coordinates of the outdoor mobile terminal, and in the 1 st stage, the steps are repeated to S201 in step S203; stage 2, indoor positioning stage, S204, using the obtained LBS base station coordinates to determine indoor mobile terminal coordinates.

The invention discloses a positioning method which can be used indoors, and differential information is generated by adopting a time differential positioning method. Specifically, as shown in fig. 5, the location coordinates of the LBS base station and the WPS base station are basically fixed, i.e. the pseudo-range Δt12 from the LBS base station to the WPS base station is relatively stable, so as to realize positioning. (note: the propagation velocity of radio waves in the same medium is constant, the propagation distance is proportional to the propagation time, and "pseudo-range" is a method of directly using the propagation time to represent the distance within the scope of the present invention).

As shown in fig. 5, the positioning service center 505 sends a positioning message MSG1 with a timestamp at a time T0, passes through a plurality of internet routers 504, arrives at the LBS base station 503 at a time T1, is forwarded by the LBS base station 503, the mobile terminal 501 receives the MSG1 at a time T3, and the WPS base station 502 receives a copy MSG1 of the positioning message MSG1 at a time T2 ^* . According to the logical relationship shown in fig. 5, the pseudo range Δt13 from the mobile terminal 501 to the LBS base station 503 is easily calculated, where Δt13 is a "pseudo" distance, and the value range is equal to or greater than 0, and the coordinates of the mobile terminal 501 are further calculated.

To achieve the above-described calculation objective, the clocks of the mobile terminal 501 and WPS base station 502 need to be synchronized. The WPS base station 502 will receive the positioning message MSG1 through the positioning message feedback ^* Is sent to the location service center 505 at time T2 of (a), and the mobile terminal 501 will receive the location message MSG1 through the location message feedbackIs sent to the location service center 505 at time T3. According to the illustrated relationship, the difference Δt23 between T3 and T2 represents the difference between the pseudo ranges of the mobile terminal 501 and the WPS base station 502 relative to the LBS base station 503, where the value range of Δt23 is the real number domain (the distance is constantly equal to or greater than 0, so Δt23 is not the distance but the difference between distances), since the positions of the base stations are fixed, the pseudo ranges Δt12 of the WPS base station 502 and the LBS base station 503 are known, and Δt12 is the distance value range is constantly equal to or greater than 0, and the calculation formula of the pseudo range Δt13 from the mobile terminal 501 to the LBS base station 503 can be obtained through deduction:

T1＝T2-Δt12 (1)

Δt13＝T3-T1＝T3-(T2-Δt12) (2)

Δt13＝T3-T2+Δt12 (3)

from the formula (2), it is known that Δt13=t3—t2+Δt12, Δt12 is the pseudo-range from the WPS base station to the LBS base station, and can be accurately measured, so the accuracy of the times T3 and T2 is a main influencing factor of the pseudo-range measurement accuracy. The precision of the pseudo range between the mobile terminal 501 and the LBS base station 503 is only related to the time precision of the mobile terminal 501 and the WPS base station 502, the higher the time precision is, the higher the measurement precision is, the no relation with the time T0 of the message sent by the positioning service center 505 is, and the no relation with the network propagation time deltat 1 is also available, i.e. the time T1 of the message received by the LBS base station has no effect in the formula (3) for calculating the pseudo range of the mobile terminal.

The scientist practice in China verifies that "single satellite" can achieve positioning, but in order to achieve accurate positioning of a mobile terminal, multiple "positioning constellations" and pseudo-ranges to corresponding constellations need to be obtained. The invention uses LBS base stations as fixed positioning constellations, and the more LBS base stations the mobile terminal searches, the more coordinates and pseudo-ranges of the obtained positioning constellations, the more accurate the positioning of the mobile terminal.

In order to achieve better effect, obtain coordinates and pseudo-ranges of multiple "positioning constellations", the present invention discloses a process of the mobile terminal interacting with the LBS base station, as shown in fig. 6. The mobile terminal scans surrounding LBS base stations to form a list, the mobile terminal selects one base station according to a preferred strategy to establish connection, after the connection is successful, the mobile terminal sends a positioning request message to a positioning service center through the LBS base station, the positioning service center starts a service process after passing authentication, and sends a positioning message and a differential message to the LBS base station, the mobile terminal performs one or more message interactions with the LBS base station, and selects the next base station according to the preferred strategy to perform message interaction to realize accurate positioning.

In order to obtain more accurate coordinates of an LBS base station, the invention discloses an innovative coordinate calculation method. The method is based on four GNSS systems (GPS, BDS, GLONASS, GALILEO) running on orbit at present, firstly, the time seed of one satellite system is obtained, then, the clock signals of other satellite systems are used for calibration to obtain high-quality clock signals, the clock signals are used for calculating position coordinates, and finally, the mobile terminal coordinates are calibrated by the clock deviation mean value and the position deviation mean value repeatedly for several times, wherein the calculation process is shown in figure 7.

The invention comprises the following key processing flows and algorithms:

the invention defines four messages of a positioning request message, a positioning message return message and a differential message, and message interaction and circulation are the key of the invention. The invention discloses a positioning method and a system for indoor use, which aim to realize the message interaction process among four components of the invention in indoor positioning, as shown in fig. 11:

1. the mobile terminal 1101 sends a location request message to the LBS base station 1102;

the lbs base station 1102 forwards the positioning request message to the positioning service center 1103;

3.1 the location services center 1103 authenticates the mobile terminal 1101, and the authentication fails to reject service;

3.2 Mobile terminal 1101 fails authentication and service cannot be used;

4. the mobile terminal 1101 successfully authenticates, the positioning service center 1103 provides service and sends a positioning message to the LBS base station 1102;

5.1 The LBS base station 1102 forwards the location message to the mobile terminal 1101;

5.2 LBS base station 1102 forwards the positioning message to WPS base station 1104;

6.1 the mobile terminal 1101 returns a location message to the LBS base station 1102;

6.2 The WPS base station 1104 returns a positioning message to the LBS base station 1102;

the lbs base station 1102 forwards the positioning message of the WPS base station 1104 and the positioning message of the mobile terminal 1101 to the positioning service center 1103;

8. The positioning service center 1103 sends a differential message to the LBS base station 1102;

the lbs base station transmits a differential message to the mobile terminal 1101.

In order to solve the problems that no satellite signal exists in indoor positioning and the positioning precision is poor by adopting the traditional LBS positioning technology, the RSSI positioning technology and the base station coverage method, the indoor positioning method can be used for adopting an indirect measurement method.

The indirect measurement method comprises two steps, namely, a first calibration process, namely, indirectly measuring the coordinates of an LBS base station by using outdoor mobile positioning; and in the second step, the coordinates of the indoor target 'mobile terminal' are measured by using the known coordinates of the LBS base station.

The first step S1 of the present invention is to determine the coordinates of the LBS base station, and specific implementation steps are described with reference to fig. 3. Namely, step S1 includes the steps of:

s101-301: the mobile terminal receives satellite positioning signals to position itself, and enables differential positioning under the condition that high-precision positioning can be carried out under the assistance of differential signals, and accurate positioning is carried out by itself. The mobile terminal calibrates the clock of the mobile terminal by using the clock of the GNSS;

s102-302: the mobile terminal selects an LBS base station and sends a positioning request message or a positioning report Wen Huiwen to the LBS base station;

s106-307: judging whether the registration is successful;

s107-308: failing registration and giving up;

In the implementation process, the positioning request message may be combined with the positioning message, and the process of step S104-306 is changed to determine whether the mobile terminal is registered, and the steps S109-311 are executed after the mobile terminal is registered, and the steps S105-309 are executed after the mobile terminal is unregistered.

The step 2S 2 of the invention is to realize the indoor positioning of the mobile terminal, and the step 2S 2 is characterized in that the LBS base station with the measured coordinates is used for measuring the coordinates of the indoor mobile terminal. The specific implementation steps are described with reference to fig. 4. Namely, step S2 includes the steps of:

s206-408: judging whether the registration is successful;

s207-409: failing registration and giving up;

The following is a procedure and explanation of the mobile terminal searching for surrounding base stations,

one of the features of the present invention is that multiple types of data traffic services of multiple operators can be used simultaneously, including 6PRS, 2/3/4/5G, wiMAXs, wiFi services. The selection of access and operators, the selection of access network types and the selection of access base stations are of special significance to the present invention. Step S2 of implementing mobile terminal positioning includes the channel selection module selecting a base station and an iterative calculation procedure, as shown in fig. 6:

s601: the mobile terminal scans surrounding LBS base stations and establishes a temporary base station information table;

s602: the mobile terminal selects an LBS base station and establishes connection with the LBS base station;

s603: judging whether the connection is established successfully or not;

s604: if the connection establishment is unsuccessful, marking as unsuccessful, discarding the base station, returning to step S602 to continue selecting the base station;

S605: if the connection is established successfully, the mobile terminal interacts with the positioning service center through the base station;

s606: the location service center iteratively calculates the coordinates of the LBS base station or the mobile terminal;

s607: repeating step S602, attempting the searched LBS base station according to the strategy;

s608: step S601 is repeated to attempt to search for surrounding available LBS base stations according to the policy.

The embodiment of the invention also preferably adopts an RSSI/Rx method, an inertial navigation technology and a WiFi positioning method at the same time, thereby further improving the robustness, reliability and availability of the system.

Claims

1. The indoor positioning method is characterized in that the method uses a mobile terminal, an LBS base station, a WPS base station and a positioning service center, and adopts four messages: the method comprises the steps of adopting an indirect measurement method to indirectly measure the coordinates of an LBS base station by utilizing the positioning of an outdoor mobile terminal in a first calibration process; a second step of positioning, namely determining the coordinates of the indoor target 'mobile terminal' by using the known coordinates of the LBS base station;

wherein, the first calibration process refers to determining an LBS base station by using the mobile terminal and the positioning service center; the second step of positioning refers to determining the coordinates of the mobile terminal by using the known coordinates of the LBS base station;

Wherein the scaling process comprises: combining the positioning request message with the positioning message, and not combining the positioning request message with the positioning message;

s106-307: judging whether the registration is successful;

s107-308: failing registration and giving up;

S113: repeating the steps S102-302, and continuously updating the coordinate information of the LBS base station coordinates;

s106-307: judging whether the registration is successful;

s107-308: failing registration and giving up;

wherein the positioning process comprises the steps of:

s206-408: judging whether the registration is successful;

s207-409: failing registration and giving up;

S212-412: the WPS base station receives the positioning message, records the receiving time and sends the positioning message back to the LBS base station; the WPS receives the differential message and gives up;

2. The positioning method as set forth in claim 1, wherein: the calibration process comprises the steps that the mobile terminal receives satellite positioning signals to position itself, differential positioning is started under the condition that high-precision positioning can be carried out under the assistance of differential signals, accurate positioning is carried out by itself, and the mobile terminal calibrates the clock of the mobile terminal by using the clock of the GNSS.

3. The positioning method as claimed in claim 1, wherein the positioning request message and the positioning message are not combined in the positioning process, comprising the steps of:

1) The mobile terminal sends a positioning request message to the LBS base station;

2) The LBS base station forwards the positioning request message to a positioning service center;

3.1 The location services center authenticating the mobile terminal 1101, the authentication failing to reject service;

4) The mobile terminal successfully authenticates, the positioning service center provides service and sends a positioning message to the LBS base station;

6.1 The mobile terminal returns a positioning message to the LBS base station;

6.2 The WPS base station returns a positioning message to the LBS base station;

7) The LBS base station forwards the positioning message return message of the WPS base station and the positioning message return message of the mobile terminal to a positioning service center;

8) The positioning service center sends a differential message to the LBS base station;

9) The LBS base station sends differential messages to the mobile terminal.

4. A positioning method usable indoors, characterized in that it uses an indirect measurement method comprising two phases: stage 1, outdoor calibration stage, which includes S201, using GNSS signal to obtain mobile terminal coordinates, S202, using mobile terminal coordinates to determine LBS base station coordinates outdoors, S203, repeating S201 and S202 several times; stage 2, indoor positioning stage, including S204, utilizing the obtained LBS base station coordinates to measure indoor mobile terminal coordinates;

The outdoor calibration stage refers to acquiring LBS base station coordinates by using GNSS signals, and specifically includes: acquiring mobile terminal coordinates by using GNSS signals, and determining the coordinates of the LBS base station by using the mobile terminal coordinates outdoors;

s106-307: judging whether the registration is successful;

s107-308: failing registration and giving up;

s106-307: judging whether the registration is successful;

s107-308: failing registration and giving up;

the indoor positioning stage refers to acquiring the coordinates of the indoor mobile terminal by using the known coordinates of the LBS base station;

wherein the positioning process comprises the steps of:

s206-408: judging whether the registration is successful;

s207-409: failing registration and giving up;

5. The indoor positioning method according to claim 4, wherein: differential information is generated by adopting a time differential positioning method, and a WPS base station with basically unchanged position coordinates with an LBS base station is adopted in the process.

6. The indoor positioning method according to claim 5, wherein: in the 2 nd stage, the positioning service center sends out a positioning message MSG1 with a time stamp at the time T0, the positioning message MSG1 arrives at the LBS base station at the time T1 through a plurality of internet routers and is forwarded by the LBS base station, the mobile terminal receives MSG1 at the time T3, the WPS base station receives a copy MSG1 of the positioning message MSG1 at the time T2, thus the pseudo range delta T13 from the mobile terminal to the LBS base station can be calculated, the value range is constantly more than or equal to 0, and the mobile terminal coordinate can be further calculated by using the value.

7. The indoor positioning method according to claim 6, wherein: the method further comprises the step of the mobile terminal scanning surrounding LBS base stations before the 1 st stage, specifically: the mobile terminal scans surrounding LBS base stations to form a list, the mobile terminal selects one base station to establish connection, after the connection is successful, the mobile terminal sends a positioning request message to a positioning service center through the LBS base station, the positioning service center starts a service process after passing authentication, and sends a positioning message and a differential message to the LBS base station, the mobile terminal interacts with the LBS base station for one or more times to indicate that the connection is successfully established, and then the mobile terminal selects the next LBS base station to repeat the steps to realize accurate positioning.

8. The indoor positioning method according to claim 7, wherein: in order to obtain the accurate coordinates of the LBS base station, the four GNSS systems currently running on-orbit: GPS, BDS, GLONASS, GALILEO, firstly obtaining a time seed of a satellite system, then calibrating by using clock signals of other satellite systems to obtain clock signals, calculating position coordinates by using the clock signals, and finally repeating the steps for several times to calibrate the coordinates of the mobile terminal by using a clock deviation mean value and a position deviation mean value.