CN104407327A - Indoor positioning method based on bidirectional wireless optical communication - Google Patents

Abstract

The invention provides an indoor positioning method based on two-way wireless optical communication. The indoor positioning method includes: the control center provides a unified time reference to realize time synchronization for N optical signal transceiver base stations; the control center sends ranging signals to the N optical signal transceiver base stations; the N optical signal transceiver base stations receive the ranging signals Afterwards, the signal is transmitted within its coverage; the optical signal transponder on the positioning terminal responds to the transmission signals of M optical signal transceiver base stations, and sends a response signal to the corresponding optical signal transceiver base station, 3≤M≤N; M optical signal The transceiver base stations respectively forward the received response signals to the control center; the control center, according to the principle of forwarding ranging, according to the sending time of the ranging signal, the location information of the M optical signal transceiver base stations, and the corresponding receiving time of the M response signals, Determine the location of the positioning terminal. The invention simplifies the functions of the positioning terminal and improves the accuracy of indoor positioning.

Description

Indoor positioning method based on two-way wireless optical communication

technical field

The invention relates to the field of positioning technology, in particular to an indoor positioning method based on two-way wireless optical communication.

Background technique

At present, several typical ideas in the research of indoor positioning technology based on LED communication at home and abroad are as follows:

(1) Single lamp positioning method based on LED-ID

This method uses LED lights as beacons, and each light has a fixed ID. The LED lamp encodes its own ID information, adopts the OOK (binary open-close keying) signal modulation method, and continuously sends information to the outside. The positioning terminal determines the position of the positioning terminal based on the ID information in the LED communication information and the coverage of the corresponding LED. .

(2) Positioning algorithm based on signal arrival angle

First, assuming the vertical distances at the spread points are the same, get a circle with the horizontal distance as the radius and centered at each spread point. Second, calculate the area of the overlap. Finally, when the size of the possible area is minimized, the vertical distance is obtained. The larger the possible area, the lower the corresponding location estimation accuracy. Finally, the user's position is estimated by the vertical distance and the average value of a large number of circle intersections.

(3) Positioning based on the quantitative relationship between light intensity and distance

The radiation of an LED chip follows a Lambertian radiation pattern. In wireless optical channels, receivers use optical filters to attenuate ambient light and focus on increasing the effective light-collecting area.

where A is the detector window area, ψ is the angle of incidence with respect to the vertical axis of the receiver, the Ts(ψ) is the gain of the optical filter, G(ψ) is the gain of the concentrator, and Ψc is the field of view concentrated FOV (FOV) in a half angle, is the angle of irradiance relative to the perpendicular to the emitter axis, and d is the distance between the emitter and receiver.

(4) Precise positioning of multiple lights

When the receiving part can receive the ID position information of three or more LED lights that are not on the same straight line, the PD array in the receiving part will receive the ID information of the three or more LED lights and the LED The relative position information mapped to the array is sent to the user terminal together, and the positioning software of the user terminal calculates the relative angle between the receiving part and the LED light by analyzing the relative position information of the LED mapped to the array, and solves the equation to obtain The current precise geographic location of the user terminal is obtained.

In the process of realizing the present invention, the applicant found that the existing indoor positioning method has the following technical defects: the positioning accuracy of a single light is low; positioning based on the signal arrival angle is limited to a two-dimensional plane; positioning based on the relationship between light intensity and distance The transmission distance is limited; the photogrammetry positioning based on multiple PD arrays is relatively complicated.

Contents of the invention

(1) Technical problems to be solved

In view of the above technical problems, the present invention provides an indoor positioning method based on two-way wireless optical communication, so as to simplify the functions of the positioning terminal and improve the accuracy of indoor positioning.

(2) Technical solutions

The present invention is an indoor positioning method based on two-way wireless optical communication. An indoor positioning system is used to realize positioning through optical signal forwarding communication. The indoor positioning system includes: a control center, an optical signal transponder installed on a positioning terminal, and a control center N optical signal transceiver base stations connected by power lines.

The indoor positioning method includes: step A: the control center provides a unified time reference to realize time synchronization for N optical signal transceiver base stations; step B: the control center sends ranging signals to the N optical signal transceiver base stations; step C: N After the optical signal transceiver base station receives the ranging signal, it transmits the signal within its coverage; Step D: The optical signal transponder on the positioning terminal responds to the transmission signals of the M optical signal transceiver base stations, and sends them to the corresponding optical signal transceiver base stations Response signal, 4≤M≤N; step E: M optical signal transceiver base stations forward the received response signal to the control center; The position information of the M optical signal transceiver base stations and the receiving time of the M response signals determine the position of the positioning terminal.

(3) Beneficial effects

It can be seen from the above technical solutions that the indoor positioning method based on two-way wireless optical communication of the present invention has the following beneficial effects:

(1) Simplify the difficulty of positioning terminal design

The solution position is changed from the positioning terminal to the control center, which reduces the difficulty of software and hardware design of the positioning terminal, and the positioning terminal only needs to install an optical signal transponder.

(2) Requirements for two-way communication

Compared with the optical signal transceiver base station, the outbound signal is a visible light signal, and the inbound signal is an infrared signal. Develop an optical signal transponder, which receives visible light signals and forwards them in the form of infrared light signals; uses optical signal transceiver base stations to receive and forward infrared light signals to form a closed-loop distance measurement.

(3) Introduce time information

To achieve indoor positioning based on the principle of pseudo-range positioning, a certain synchronization accuracy needs to be maintained between each LED light, so time information needs to be introduced.

(4) High positioning accuracy

Compared with other solutions, the indoor positioning scheme based on two-way wireless optical communication can transmit more information due to the characteristics of high frequency and high bandwidth of wireless light, and provide technical support for high-precision positioning. The strong boundary effect characteristics of LED lights also make it possible to integrate multiple algorithm solutions when designing algorithms to achieve high-precision positioning.

Description of drawings

Fig. 1 is a schematic structural diagram of implementing an indoor positioning system based on two-way wireless optical communication according to the present invention;

Fig. 2 is a schematic diagram of two optical signal transceiver base stations performing time synchronization in the indoor positioning system described in Fig. 1;

Fig. 3 is a schematic diagram of signal propagation time relationship for one path of positioning signals in the indoor positioning system shown in Fig. 1 .

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be noted that, in the drawings or descriptions of the specification, similar or identical parts all use the same figure numbers. Implementations not shown or described in the accompanying drawings are forms known to those of ordinary skill in the art. Additionally, while illustrations of parameters including particular values may be provided herein, it should be understood that the parameters need not be exactly equal to the corresponding values, but rather may approximate the corresponding values within acceptable error margins or design constraints. The directional terms mentioned in the embodiments, such as "upper", "lower", "front", "rear", "left", "right", etc., are only referring to the directions of the drawings. Therefore, the directional terms used are for illustration and not for limiting the protection scope of the present invention.

The two-way wireless optical communication indoor positioning scheme based on the forwarding system proposed by the present invention draws on the working principle of the forwarding satellite navigation, and the positioning terminal is equipped with a transponder to return the visible light signal broadcast by the optical signal transceiver base station in the form of an infrared signal. , to form a spontaneous and self-receiving link, and calculate and locate the terminal position through the principle of pseudo-range measurement.

In an exemplary embodiment of the present invention, a high-precision positioning method based on two-way wireless optical communication for locating shopping carts in a supermarket is provided. FIG. 1 is a schematic structural diagram of an indoor positioning system in a high-precision indoor positioning method based on two-way wireless optical communication according to an embodiment of the present invention. As shown in FIG. 1 , the indoor positioning system includes: a control center, an optical signal transponder installed on a shopping cart to be located, and at least four optical signal transceiver base stations. Among them, the LED lights on the roof of the supermarket serve as the light source and the optical signal transceiver base station at the same time, and the signal transmission between the control center and the optical signal transceiver base station can be completed by the power line carrier.

In this embodiment, the high-precision navigation indoor positioning method based on two-way wireless optical communication includes:

Step A: The control center synchronizes the time of the four optical signal transceiver base stations;

In order to ensure the positioning accuracy, it is necessary to accurately position each LED light first. In addition, since the present invention adopts the repeating ranging principle, which is based on the time of signal transmission, the time of each LED lamp must be synchronized.

FIG. 2 is a schematic diagram of time synchronization between two optical signal transceiver base stations in the indoor positioning system shown in FIG. 1 . As shown in FIG. 2 , the time signal is sent to each optical signal transceiver base station through the power carrier, and then each optical signal transceiver base station performs more accurate time calibration. Light A sends the local time signal to the shopping cart to be positioned, and sends the time signal of light A to light B through the transponder of the shopping cart to be positioned, and compares it with the local time signal of light B to measure the time signal from light A to light B delivery delay. When lamp A transmits a signal, lamp B transmits a signal in the same way and is received by lamp A. Through the data exchange between the two stations, the high-precision clock difference of the local time of the two places is obtained.

Step B: the control center sends ranging signals to the four optical signal transceiver base stations;

Step C: Each of the four optical signal transceiver base stations, after receiving the ranging signal, transmits to its coverage area based on the outbound signal;

Step D: The optical signal transponder of the shopping cart to be positioned responds to at least four ranging signals from the optical signal transceiver base stations, and sends a response signal to the corresponding optical signal transceiver base stations;

Please refer to Figure 1. For the optical signal transceiver base station, it transmits a visible light signal to the shopping cart to be positioned within the coverage area. As shown by the solid line, the optical signal transponder of the shopping cart to be positioned responds to the ranging signal of the LED light. A response signal is sent to the corresponding optical signal transceiver base station, and the response signal is an inbound signal based on infrared communication, as shown by a dotted line. The outbound signal and inbound signal of the optical signal transceiver base station form a closed-loop ranging.

In this embodiment, the optical signal transceiver base station is the basis for realizing indoor positioning, and at the same time, it is necessary to control the influence of other redundant optical signals on the positioning result. The high-frequency and high-bandwidth characteristics of wireless optical communication provide technical support for high-speed and large-scale transmission of information.

Step E: After receiving the response signal forwarded by the optical signal transponder on the shopping cart to be positioned, the optical signal transceiver base station sends it to the control center;

Step F: The control center determines the location of the shopping cart to be located according to the principle of forwarding ranging, according to the time difference between the ranging signal and the response signal, and the location of the corresponding optical signal transceiver base station.

In this embodiment, the forwarding distance measurement principle is adopted, and the calculation and data processing are carried out in the control center. The optical signal transponder on the shopping cart to be positioned only needs to forward the signal or put forward specific requirements and send it to the optical signal transceiver base station (LED light), the specific calculation process is completed by the control center in the background, which reduces the design complexity of the side to be positioned.

The implementation process of the indoor positioning system based on bidirectional wireless optical communication in this embodiment will be described in detail below.

Fig. 3 is a schematic diagram of signal propagation time relationship for one path of positioning signals in the indoor positioning system shown in Fig. 1 . As shown in Figure 3, for each positioning signal, the closed-loop ranging distance includes: the ranging signal is sent from the control center to the optical signal transceiver base station, and the optical signal transceiver base station transmits the signal to the optical signal on the shopping cart to be positioned The forwarding device, the optical signal forwarding device performs signal forwarding, and at the same time attaches the ID information of the shopping cart to be located. Then, the optical signal reaches the optical signal transceiver base station through the transponder. total propagation time It consists of several parts:

${\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the formula, _τ1 is the power carrier time delay between the control center and the optical signal transceiver base station; _τ2 is the line delay of the optical signal transceiver base station transmitter; _t3 is the optical signal from the optical signal transceiver base station transmitter to the shopping cart The propagation time of the receiving end of the signal transponder; τ ₄ is the time delay introduced by the transponder of the optical signal transponder; t ₅ is the propagation time from the transmitting end of the optical signal transponder to the receiving end of the optical signal transceiver base station; τ ₆ is the time delay of the optical signal transponder base station receiving end Line delay; ε _i is the measurement error caused by various factors.

Among them, τ ₁ and τ ₂ can be obtained through actual measurement; the time delay τ ₄ of the optical signal transponder carried by the shopping cart to be positioned can also be obtained through actual measurement (the time delay of the transponder is calibrated, and the time delay value may vary with time. change, the amount of change can be included in the item ε _i ); and the line time delay _τ6 of the optical signal transceiver base station receiver can be obtained by instrument measurement, and the above formula is rewritten as:

${\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

It can be known from the above formula that if the values of τ ₁ , τ ₂ , τ ₄ , τ ₆ can be obtained and measured Then (t ₃ +t ₅ ) (including ε _i error) can be obtained, that is, the propagation time from the transmitting end of the optical signal transceiver base station to the receiving end of the optical signal transponder of the shopping cart to be located and the time from the transmitting end of the optical signal transponder to the optical signal The sum of the propagation time of the transceiver base station receiver, multiplied by the speed of light c, is the sum of the two propagation distances.

According to the LED-ID information contained in the positioning signal, the position of the optical signal transceiver base station can be known. Let the position coordinates of the optical signal transceiver base station be (x _s , y _s , z _s ), and the instantaneous position coordinates of the shopping cart to be positioned are (x _t , y _t , z _t ), then:

$\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the above formula, the position (x _s , y _s , z _s ) of the optical signal transceiver base station is known, and there are only three unknowns x _t , y _t and z _t . For each optical signal transceiver base station, in the case of ignoring the measurement error ε _i , there is the following relationship:

$\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

If the propagation time of the signals transmitted by the three optical signal transceiver base stations from the shopping cart to be positioned to the receiving antenna of the positioning station is measured, the position of the shopping cart to be positioned can be solved from the three sets of spherical equations.

However, there may be a deviation Δt between the local time of the optical signal transceiver base station and the system reference time, and this time deviation exists in each receiving measurement. Assuming that the deviation of multiple LEDs is the same Δt, if the deviation Δt is solved as an unknown, then the sum of the two propagation times (t ₃ +t ₅ ) can be accurately measured, namely:

$\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

This requires adding an additional light for measurement, and by measuring four or more LED lights or four or more distances, and solving more than four sets of observation equations, the position of the positioning terminal (x _t , y _t , z _t ) and the local time deviation Δt of the LED lamp.

So far, the present embodiment has been described in detail with reference to the drawings. According to the above description, those skilled in the art should have a clear understanding of the indoor positioning system based on two-way wireless optical communication of the present invention.

In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and those skilled in the art can easily modify or replace them, for example:

(1) The above embodiment takes the shopping cart in the supermarket as an example to illustrate, and the positioning terminal can also be other objects, such as: mining vehicles in underground mines, emergency carts in hospitals, etc.;

(2) In the above embodiment, the two-way signal transmission between the control center and the optical signal transceiver base station is carried out by using the power carrier, and a dedicated line can also be used to carry out the two-way signal transmission between the two.

In summary, in the indoor positioning system based on two-way wireless optical communication of the present invention, the two-way communication between the positioning terminal and the optical signal transceiver base station improves the interactivity of navigation and communication integration, and realizes the indoor high-speed positioning system based on two-way wireless optical communication. Precision positioning.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. the indoor orientation method based on double-direction radio optical communication, it is characterized in that, an indoor locating system is utilized to realize location by the forwarding communication of light signal, this indoor locating system comprises: control center, the optical repeater be installed on locating terminal, and the N number of optical signal transceiver base station to be connected by line of electric force with control center, this indoor orientation method comprises:

Steps A: control center provides the unified time synchronized of time reference realization to described N number of optical signal transceiver base station;

Step B: control center sends distance measuring signal to described N number of optical signal transceiver base station;

Step C: after described N number of optical signal transceiver base station receives distance measuring signal, transmit in its coverage;

Step D: transmitting of optical repeater response M the optical signal transceiver base station on locating terminal, sends answer signal to corresponding optical signal transceiver base station, 4≤M≤N;

Step e: the answer signal received is forwarded to control center by described M optical signal transceiver base station respectively;

Step F: control center, according to forwarding range measurement principle, according to transmitting time, the positional information of a M optical signal transceiver base station, the time of reception of a corresponding M answer signal of distance measuring signal, determines the position of locating terminal.

2. indoor orientation method according to claim 1, is characterized in that, described step e comprises:

Sub-step E1, control center, according to forwarding range measurement principle, sets up the spherical equation with M optical signal transceiver base station distance relation for each locating terminal;

Sub-step E2, a simultaneous solution M spherical equation, obtains the position of locating terminal.

3. indoor orientation method according to claim 2, is characterized in that:

In described sub-step E1, for optical signal transceiver base station, itself and locating terminal meet following spherical equation:

$c\&CenterDot;[t_{{\mathrm{\&Sigma;}}_i}-(2\&CenterDot;{\mathrm{\&tau;}}_1+{\mathrm{\&tau;}}_2+{\mathrm{\&tau;}}_4+{\mathrm{\&tau;}}_6)]=2\&CenterDot;\sqrt{{(x_s-x_t)}^2+{(y_s-y_t)}^2+{(z_s-z_t)}^2}$

Wherein, (x _t, y _t, z _t) be the position of locating terminal, (x _s, y _s, z _s) be the position of current optical signal transceiver base station, for sending distance measuring signal from control center to receiving answer signal total travel-time, τ ₁for from control center to the time delay of optical signal transceiver base station; τ ₂for the circuit time delay of optical signal transceiver transmission end of base station; τ ₄for the optical repeater on locating terminal forwards the time delay introduced; τ ₆for the circuit time delay of optical signal transceiver base station receiving end.

4. indoor orientation method according to claim 2, is characterized in that, described M >=4;

In described sub-step E1, for optical signal transceiver base station, itself and locating terminal meet following spherical equation:

$c\&CenterDot;[t_{{\mathrm{\&Sigma;}}_i}-(2\&CenterDot;{\mathrm{\&tau;}}_1+{\mathrm{\&tau;}}_2+{\mathrm{\&tau;}}_4+{\mathrm{\&tau;}}_6)+\mathrm{\&Delta;t}]=2\&CenterDot;\sqrt{{(x_s-x_t)}^2+{(y_s-y_t)}^2+{(z_s-z_t)}^2}$

Wherein, (x _t, y _t, z _t) be the position of locating terminal, (x _s, y _s, z _s) be the position of current optical signal transceiver base station, for sending distance measuring signal from control center to receiving answer signal total travel-time, τ ₁for from control center to the time delay of optical signal transceiver base station; τ ₂for the circuit time delay of optical signal transceiver transmission end of base station; τ ₄for locating terminal optical signal transponder forwards the time delay introduced; τ ₆for the circuit time delay of optical signal transceiver base station receiving end, Δ t is the deviation that the local zone time of optical signal transceiver base station and system reference time exist.

5. indoor orientation method according to claim 1, is characterized in that:

In described step C, comprise in transmitting: the characteristic information of current optical signal transceiver base station;

In described step D, comprise in answer signal: the characteristic information of locating terminal, the characteristic information of optical signal transceiver base station.

6. indoor orientation method according to claim 1, is characterized in that, carries out two-way signaling transmission between described control center and described multiple optical signal transceiver base station by power line carrier.

7. indoor orientation method according to claim 1, is characterized in that, in described step C, optical signal transceiver base station launches distance measuring signal by visible light communication to its coverage.

8. indoor orientation method according to claim 1, is characterized in that, the optical repeater in described step D on locating terminal sends answer signal by infrared communication to corresponding optical signal transceiver base station.

9. indoor orientation method according to any one of claim 1 to 8, is characterized in that, optical signal transceiver base station can room lighting again can visible light communication.

10. indoor orientation method according to any one of claim 1 to 8, is characterized in that, described locating terminal is the first aid trammer of the shopping cart in supermarket, the mining vehicle of underground mine or hospital.