Indoor positioning method, device, storage medium and system

Abstract

The present invention provides an indoor positioning method, device, storage medium and system, the method comprising: receiving a beacon signal emitted by an LED light source to obtain an actual received signal; calculating the likelihood ratio between the actual received signal and the theoretical received signal of the beacon signal at the center position of each grid in the positioning area; determining the target grid with the largest absolute value of the likelihood ratio according to the likelihood ratio calculation result, and determining the position of the positioning terminal according to the target grid with the largest absolute value of the likelihood ratio. The new indoor positioning method proposed by the present invention has been verified to be able to achieve a positioning accuracy of 0.5mm in a 30dB signal-to-noise ratio environment, which is very close to the theoretical limit, breaking through the technical bottleneck of traditional indoor positioning accuracy and solving the technical problem of insufficient positioning accuracy in traditional indoor positioning methods based on visible light.

Description

Technical Field

[0001] The present invention relates to the field of indoor positioning technology, and in particular to an indoor positioning method, device, storage medium and system. Background Art

[0002] The commercial use of wide-area wireless communication systems represented by the fifth generation (5G) mobile communication network and various types of Internet of Things generates a massive amount of connections and information flows, among which the traffic in indoor scenes accounts for up to 80%, because the core participants of economic activities, such as people, machines, equipment, production process lines, etc., are mostly in indoor environments. Position is one of the core information for electronic information systems to generate service efficiency and economic value. At present, the global satellite navigation system (GNSS) is the most mainstream wide-area wireless positioning and navigation system. In open outdoor spaces, the positioning accuracy of common multi-mode GNSS receivers can reach a circular error probability of 2.5 meters. The use of dedicated positioning performance enhancement facilities can improve the positioning accuracy to the centimeter level. However, due to the complex propagation environment and the obstruction of GNSS signals, the positioning accuracy of GNSS indoors is not ideal. At present, the network-enhanced satellite positioning system (A-GNSS, Assisting-GNSS) is widely used, which can achieve satellite navigation positioning under complex conditions such as certain obstructions or semi-open areas. In the 17th latest evolution version of 5G, high-precision indoor and outdoor positioning is required, and the availability and timeliness of indoor and outdoor full-scenario positioning services are guaranteed. The 17th latest evolution version of 5G recommends integrating 5G, GNSS, terrestrial beacon systems (TBS, Terrestrial Beacon Systems), sensors (such as: air pressure, inertial navigation), wireless LAN / Bluetooth (WLAN, Bluetooth), etc. to achieve indoor positioning accuracy of 0.2-10 meters.

[0003] Light Emitting Diode (LED) has extremely high luminous efficiency. Since the mid-1990s, LED has absolutely dominated the indoor lighting system. At the same time, due to the advantages of LED such as green color and ultra-high bandwidth, the development of LED-based visible light communication (VLC) system in indoor scenes can become an important supplement to 5G / 6G and be integrated into the 5G / 6G network architecture. In addition, using LED as a carrier to develop indoor positioning systems and technologies can solve the problems of poor indoor transmission quality and lack of positioning accuracy of the aforementioned wireless positioning system during the lighting process. It is very suitable for enhancing the indoor positioning performance of 5G, which meets the urgent development needs of carbon neutrality, and can also avoid the problems of installation and cost in the development of dedicated indoor positioning systems.

[0004] LED-based visible light positioning is a very popular research topic and industry development frontier. In the positioning system based on photodiode (PD), the positioning system is divided into positioning terminals and network devices. The network devices of the positioning system emit visible light signals that meet specific rules, which are called positioning beacons. In the positioning network, positioning beacons are networked through time division multiplexing, frequency division multiplexing, code division multiplexing, space division multiplexing, etc., so that the positioning terminal can distinguish the positioning beacons emitted by the LEDs in the positioning network.

[0005] The positioning algorithm of the positioning terminal is mainly to measure the intensity, time and direction of the visible light beacon emitted by each LED of the network device independently or jointly, and then use geometric positioning, grid subdivision, deep learning, etc., and further combine linear least squares, nonlinear least squares, linear regression, clustering and other optimization algorithms to achieve indoor visible light positioning. However, the current visible light positioning method still has the problem of insufficient positioning accuracy, especially in the case of a high signal-to-noise ratio in the indoor environment, it is more difficult to ensure indoor positioning accuracy. Summary of the invention

[0006] Based on this, the purpose of the present invention is to provide an indoor positioning method, device, storage medium and system to solve the technical problem of insufficient positioning accuracy in existing indoor positioning methods based on visible light.

[0007] An indoor positioning method according to an embodiment of the present invention is applied to a positioning terminal and is used to locate the position of the positioning terminal in a positioning area preset indoors, the positioning area is pre-divided into a plurality of grids, a positioning network device is arranged indoors, the positioning network device includes at least one LED light source, and the LED light source can periodically transmit a beacon signal to the positioning area in a pulse form, the method includes:

[0008] Receiving a beacon signal emitted by the LED light source to obtain an actual received signal;

[0009] Calculating a likelihood ratio between the actual received signal and a theoretical received signal for the beacon signal at a center position of each grid of the positioning area;

[0010] According to the likelihood ratio calculation result, a target grid with the largest absolute value of the likelihood ratio is determined, and the position of the positioning terminal is determined according to the target grid with the largest absolute value of the likelihood ratio.

[0011] In addition, an indoor positioning method according to the above embodiment of the present invention may also have the following additional technical features:

[0012] Furthermore, before positioning, the following steps are also included:

[0013] Dividing the positioning area into grids, and establishing a corresponding relationship between the grids and the coordinates of their center positions;

[0014] The steps of dividing the positioning area into grids and establishing a corresponding relationship between the grids and the coordinates of the central positions thereof specifically include:

[0015] The closed area formed by connecting the vertex coordinates of the positioning area is divided into two parts according to the preset grid interval (g x ,g y ,g z ), from the vertex coordinates preset in the positioning area First, the grids are evenly divided and numbered along the X-axis, Y-axis, and Z-axis directions to obtain the numbered coordinates of each grid (s x ,s y ,s z ), s x 、s y 、s z are all natural numbers;

[0016] According to the numbered coordinates (s x ,s y ,s z ), calculate the center position coordinates of each grid and establishing a corresponding relationship between the grid and the coordinates of its center position;

[0017] in,

[0018] Furthermore, after the step of dividing the positioning area into grids and establishing a corresponding relationship between the grids and the coordinates of the central positions thereof, the step further includes:

[0019] Placing the positioning terminal at the center of the designated grid for scene learning to learn the time and channel gain of each LED light source transmitting the beacon signal;

[0020] The step of placing the positioning terminal at the center of a designated grid for scene learning to learn the time and channel gain of each LED light source transmitting a beacon signal specifically includes:

[0021] Place the positioning terminal at the center of the jth grid, and make the LED light source periodically transmit a beacon signal to the positioning terminal in a pulse form;

[0022] Obtaining the actual received signal of the positioning terminal for the beacon signal and arrival time

[0023] Calculate the distance between the jth grid center and each of the LED light sources and channel gain And calculate the time φ of each LED light source transmitting the kth beacon signal i (k); where

[0024]

[0025]

[0026] φ i (k) = φ i (0)+k×T I ;

[0027]

[0028] Where i represents the number of LED light sources, K represents the number of detections, k represents the number of beacon signals, k = 0, 1, ..., K-1, represents the channel gain of the beacon signal emitted by the i-th LED light source propagating to the center of the j-th grid, represents the distance from the jth grid center to the ith LED light source, φ i (k) represents the time when the i-th LED light source sends the k-th beacon signal, T I represents the emission time interval of the beacon signal, c represents the speed of light, represents the emission gain of the i-th LED light source in the direction pointing to the j-th grid center, Pa r (i,j) represents the receiving gain of the terminal located in the direction of the i-th LED light source from the j-th grid center. Represents the center position coordinates of the jth grid, represents the position coordinates of the i-th LED light source, φ i (0) represents the time when the i-th LED light source transmits the 0th beacon signal.

[0029] Furthermore, the number of the LED light sources is multiple, and the step of receiving the beacon signal emitted by the LED light source to obtain the actual received signal includes:

[0030] Each beacon signal emitted by each of the LED light sources is received to obtain a plurality of the actual received signals.

[0031] Further, the step of calculating the likelihood ratio between the actual received signal and the theoretical received signal for the beacon signal at the center position of each grid of the positioning area includes:

[0032] According to the center position coordinates of each grid, the time when each LED light source transmits the beacon signal, and the channel gain, the likelihood ratio between each actual received signal and the theoretical received signal of the beacon signal at the center position of each grid in the positioning area is calculated.

[0033] Furthermore, the calculation formula of the likelihood ratio is:

[0034]

[0035] in:

[0036]

[0037] Where γ represents the likelihood ratio, M represents the number of LED light sources, i = 0, 1, ..., M-1, y i (k) represents the kth beacon signal emitted by the i-th LED light source received by the positioning terminal, P i represents the emission power of the i-th LED light source, s represents the grid number, It represents the overlapping time width between the expected pulse observation window and the actual observation window of the positioning terminal for the kth beacon signal emitted by the i-th LED light source at the grid s, T w Indicates the duration of a beacon signal within a beacon signal transmission time interval. represents the emission gain of the i-th LED light source in the direction pointing to the center of the s-th grid, Pa r (i,s) represents the receiving gain of the terminal located in the direction of the ith LED from the center of the sth grid. represents the distance between the i-th LED light source and the s-th grid, Represents the channel gain of the beacon signal emitted by the i-th LED light source propagating to the center of the s-th grid.

[0038] Furthermore, the step of determining the position of the positioning terminal according to the target grid having the largest absolute value of the likelihood ratio includes:

[0039] Determine the coordinates of multiple vertex positions of the target mesh according to the center position coordinates of the target mesh;

[0040] Calculate, according to the coordinates of each vertex position, a likelihood ratio between the actual received signal and a theoretical received signal at each vertex position for the beacon signal, to obtain a likelihood ratio of each vertex position;

[0041] The likelihood ratio of each vertex position and the coordinates of each vertex position are multiplied and then divided by the sum of the likelihood ratios of each vertex position to obtain the position coordinates of the positioning terminal.

[0042] An indoor positioning device according to an embodiment of the present invention is applied to a positioning terminal and is used to locate the position of the positioning terminal in a positioning area preset indoors, the positioning area is pre-divided into a plurality of grids, a positioning network device is arranged indoors, the positioning network device includes at least one LED light source, and the LED light source can periodically transmit a beacon signal to the positioning area in a pulse form, the device includes:

[0043] A signal receiving module, used to receive the beacon signal emitted by the LED light source and obtain an actual received signal;

[0044] A likelihood ratio calculation module, used to calculate the likelihood ratio between the actual received signal and the theoretical received signal for the beacon signal at the center position of each grid of the positioning area;

[0045] The indoor positioning module is used to determine the target grid with the largest absolute value of the likelihood ratio according to the likelihood ratio calculation result, and determine the position of the positioning terminal according to the target grid with the largest absolute value of the likelihood ratio.

[0046] The present invention also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the indoor positioning method described above is implemented.

[0047] The present invention also provides an indoor positioning system, the indoor positioning system comprising:

[0048] A positioning network device is arranged indoors, and the positioning network device includes at least one LED light source, and the LED light source can periodically transmit a beacon signal in a pulse form to a preset positioning area in the room, and the positioning area is pre-divided into a plurality of grids.

[0049] The positioning terminal is arranged indoors, and includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the indoor positioning method as described above is implemented to locate the position of the positioning terminal in the positioning area.

[0050] Compared with the existing technology: by calculating the likelihood ratio between the actual received signal of the positioning terminal and the theoretical received signal of the beacon signal at the center position of each grid pre-divided in the positioning area, the target grid with the largest absolute value of the likelihood ratio is found, and then the position of the positioning terminal is determined based on the target grid with the largest absolute value of the likelihood ratio. This new indoor positioning method has been proven to be able to achieve a positioning accuracy of 0.5mm in an environment with a signal-to-noise ratio of 30dB, which is very close to the theoretical limit. It breaks through the technical bottleneck of traditional indoor positioning accuracy and solves the technical problem of insufficient positioning accuracy in traditional indoor positioning methods based on visible light. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of the structure of an indoor positioning system provided by an embodiment of the present invention;

[0052] Figure 2 A waveform diagram of a beacon signal emitted by each LED light source provided in an embodiment of the present invention;

[0053] Figure 3 is a flow chart of an indoor positioning method in a first embodiment of the present invention;

[0054] Figure 4 is a flow chart of an indoor positioning method in a second embodiment of the present invention;

[0055] Figure 5 FIG. 4 is a schematic diagram of the structure of an indoor positioning device in a third embodiment of the present invention.

[0056] The following specific implementations will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0057] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0058] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0060] The following embodiments can be applied to Figure 1 Among the indoor positioning systems shown, Figure 1 An indoor positioning system provided in an embodiment of the present invention is shown, and the indoor positioning system includes a positioning network device and a positioning terminal, wherein:

[0061] The positioning network equipment and the positioning terminal are both arranged indoors. The positioning terminal is in a preset positioning area indoors. The indoor positioning system is mainly used to locate the position of the positioning terminal in the positioning area. The positioning network equipment includes a plurality of dispersed LED light sources. The LED light sources can periodically transmit pre-modulated beacon signals (i.e., visible light signals) to the positioning area in the form of pulses. The positioning terminal receives the beacon signal and locates its own position based on the received beacon signal.

[0062] Specifically, the positioning area can be any legal area indoors, such as a living room, hall, bedroom, conference room, office, etc. LED light sources can be arranged on the ceiling of the positioning area, and the LED light sources can provide both indoor lighting and indoor positioning. The positioning terminal can be, but is not limited to, a robot (such as a sweeping robot), a mobile phone, a logistics vehicle, etc., which can move in the positioning area. For example, a sweeping robot can clean in the positioning area. During the cleaning process, the position of the sweeping robot is located by the indoor positioning system.

[0063] In addition, in the embodiment of the present invention, the positioning network device also includes a plurality of dimmers, each LED light source is connected to a dimmer, and the parameters of the dimmers are controlled so that the LED light source can emit beacon signals with different parameters. Figure 2 As shown, shown are the waveforms of the beacon signals emitted by four LED light sources. It can be seen that there are differences in the waveforms of the beacon signals emitted by the four LED light sources. Specifically, the interval time of the pulse pairs within a pulse cycle is different, which are 7us, 5us, 3us and 2us respectively. In this way, according to the different interval time of the pulse pairs, the positioning terminal can determine the LED light source corresponding to the received signal, that is, it knows which LED light source sends the current received signal, which greatly facilitates indoor positioning.

[0064] It should be pointed out that Figure 1 The structure shown does not constitute a limitation on the indoor positioning system. In other embodiments, the indoor positioning system may include fewer or more components than shown in the figure, or combine certain components, or arrange the components differently.

[0065] Embodiment 1

[0066] See also Figure 3 , shown is an indoor positioning method in the first embodiment of the present invention, which is applied to a positioning terminal and is used to locate the position of the positioning terminal in a preset positioning area indoors. The positioning area is pre-divided into multiple grids. A positioning network device is arranged indoors. The positioning network device includes at least one LED light source. The LED light source can periodically transmit a beacon signal to the positioning area in a pulse form. The method specifically includes steps S01-S03.

[0067] Step S01, receiving a beacon signal emitted by the LED light source to obtain an actual received signal.

[0068] Specifically, after the LED light source is turned on and / or when a positioning request is received, the LED light source will periodically radiate a beacon signal to the positioning area in a pulsed form. At this time, the positioning terminal in the positioning area will receive each beacon signal emitted by each LED light source and obtain multiple actual received signals.

[0069] Step S02: Calculate the likelihood ratio between the actual received signal and the theoretical received signal for the beacon signal at the center position of each grid in the positioning area.

[0070] It should be noted that before positioning, the positioning area should be divided into grids. Before grid division, the vertex coordinates of the positioning area need to be determined. For example, when the positioning area is a rectangular area, the coordinates of the four vertices (i.e., corner points) of the rectangular area need to be determined. After determining the vertex coordinates of the positioning area, the closed area formed by the connecting lines of the vertex coordinates is determined as the positioning area. Then, starting from any vertex coordinate of the positioning area, the grids are evenly divided and numbered along the X-axis, Y-axis, and Z-axis directions. The grid interval can be preset, for example, 1 cm to obtain the coordinates of each grid. When the coordinates of each grid and the grid interval are known, the center position coordinates of each grid can be determined, thereby establishing a corresponding relationship between each grid and its center position coordinates.

[0071] During positioning, the theoretical receiving signal of the center position of each grid for the beacon signal can be calculated according to the beacon parameters of the LED light source and the coordinates of the center position of each grid, and the theoretical receiving signal of each grid can be obtained. Then, the likelihood ratio between the actual receiving signal and the theoretical receiving signal of each grid can be calculated to obtain the likelihood ratio of each grid, thereby obtaining a likelihood ratio matrix composed of the likelihood ratios of each grid.

[0072] Step S03: determining a target grid with the largest absolute value of the likelihood ratio according to the likelihood ratio calculation result, and determining the position of the positioning terminal according to the target grid with the largest absolute value of the likelihood ratio.

[0073] In this step, the likelihood ratio with the largest absolute value can be found in the likelihood ratio matrix output in step S02, so as to determine the grid corresponding to the likelihood ratio with the largest absolute value, thereby determining the target grid with the largest absolute value of the likelihood ratio. The center position coordinates of the target grid are the most likely location of the positioning terminal.

[0074] In summary, the indoor positioning method in the above-mentioned embodiment of the present invention calculates the likelihood ratio between the actual received signal of the positioning terminal and the theoretical received signal of the beacon signal at the center position of each grid pre-divided in the positioning area, finds the target grid with the largest absolute value of the likelihood ratio, and then determines the position of the positioning terminal according to the target grid with the largest absolute value of the likelihood ratio. This new indoor positioning method has been verified to be able to achieve a positioning accuracy of 0.5mm in an environment with a signal-to-noise ratio of 30dB, which is very close to the theoretical limit, breaking through the technical bottleneck of traditional indoor positioning accuracy and solving the technical problem of insufficient positioning accuracy in traditional indoor positioning methods based on visible light.

[0075] Embodiment 2

[0076] See also Figure 4 , shown is an indoor positioning method in the second embodiment of the present invention, which is applied to a positioning terminal and is used to locate the position of the positioning terminal in a preset positioning area indoors. The positioning area is pre-divided into multiple grids. A positioning network device is arranged indoors. The positioning network device includes at least one LED light source. The LED light source can periodically transmit a beacon signal to the positioning area in a pulse form. The method specifically includes steps S11 to S18.

[0077] Step S11, dividing the positioning area into grids, and establishing a corresponding relationship between the grids and the coordinates of their center positions.

[0078] In some specific implementations of this embodiment, step S11 may specifically include:

[0079] The closed area formed by connecting the vertex coordinates of the positioning area is divided into two parts according to the preset grid interval (g x ,g y ,g z ), from the vertex coordinates preset in the positioning area First, the grids are evenly divided and numbered along the X-axis, Y-axis, and Z-axis directions to obtain the numbered coordinates of each grid s (s x ,s y ,s z ), (s x ,s y ,s z ) represent the grid numbers along the X-axis, Y-axis, and Z-axis directions, starting from 0, i.e., s x 、s y 、s z are all natural numbers;

[0080] According to the numbered coordinates (s x ,s y ,s z), calculate the center position coordinates of each grid and establishing a corresponding relationship between the grid and the coordinates of its center position;

[0081] in,

[0082] The vertex coordinates of the positioning area can be obtained by user input, gsp positioning, or by establishing a coordinate system based on the length, width and height of the positioning area. It is the smallest vertex coordinate in the three directions of X-axis, Y-axis and Z-axis among the vertex coordinates of the positioning area, and can also be called the coordinate origin.

[0083] In addition, in some optional cases of this embodiment, in the process of mesh division, after the step of establishing the corresponding relationship between the mesh and the coordinates of the center position thereof, the following steps may also be included:

[0084] Construct a grid set S of the positioning area. If the coordinates If the element s is inside the region enclosed by the vertex coordinates of the positioning region and within the legal position set Ω of the terminal, then the element s is added to the grid set S and the three numbers (s x ,s y ,s z ).

[0085] That is, by constructing a grid set S, it is convenient to perform positioning analysis on each grid later. At the same time, it is also possible to exclude some illegal positions of terminals after grid division. In other words, when the user does not want the positioning terminal to move to a certain position in the positioning area, the coordinates of the position can be recorded in advance, so that the coordinates of the position can be excluded in advance, forming a legal position set Ω of the terminal in the positioning area, and then the grids s divided by the positioning area are screened with the legal position set Ω, forming a grid set S corresponding to the legal position of the positioning terminal in the positioning area.

[0086] Step S12, placing the positioning terminal at the center of the designated grid to perform scene learning, so as to learn the time, channel gain, time error, and emission time set of each LED light source transmitting the beacon signal.

[0087] In some specific implementations of this embodiment, step S11 may specifically include:

[0088] Place the positioning terminal at the center of the jth grid, and make the LED light source periodically transmit a beacon signal to the positioning terminal in the form of pulses, and count the beacon signals, which is represented by k;

[0089] Obtaining the actual received signal of the positioning terminal for the beacon signal and arrival time

[0090] Calculate the distance between the jth grid center and each of the LED light sources and channel gain

[0091] Calculate the time φ when each LED light source transmits the 0th beacon signal i (0);

[0092] Calculate the time φ of each LED light source transmitting the kth beacon signal i (k); where

[0093]

[0094] φ i (k) = φ i (0)+k×T I ;

[0095]

[0096] Where i represents the number of LED light sources, K represents the number of detections, k represents the number of beacon signals, k = 0, 1, ..., K-1, represents the channel gain of the beacon signal emitted by the i-th LED light source propagating to the center of the j-th grid, represents the distance from the jth grid center to the ith LED light source, φ i (k) represents the time when the i-th LED light source sends the k-th beacon signal, T I represents the emission time interval of the beacon signal, c represents the speed of light, represents the emission gain of the i-th LED light source in the direction pointing to the j-th grid center, Pa r (i,j) represents the receiving gain of the terminal located in the direction of the i-th LED light source from the j-th grid center. Represents the center position coordinates of the jth grid, represents the position coordinates of the i-th LED light source, φ i (0) represents the time when the i-th LED light source transmits the 0th beacon signal;

[0097] The time error is:

[0098] The time sets for each LED to transmit the kth beacon signal are: ε is the position error tolerance, and α is the time domain search step factor.

[0099] It should be noted that the purpose of scene learning in step S12 is to allow the positioning terminal to know in advance the parameters such as the time, channel gain, time error, and transmission time set of the beacon signal transmitted by each LED light source. In this way, in the subsequent actual positioning process, the positioning terminal can accurately calculate the theoretical receiving signal of the beacon signal emitted by different LED light sources at the center position of each grid based on this pre-mastered information, thereby achieving high-precision positioning.

[0100] In addition, step S11-step S12 are preparatory steps before actual positioning, and the subsequent steps S13-step S18 are the actual terminal positioning process.

[0101] Step S13, receiving each beacon signal emitted by each of the LED light sources to obtain a plurality of the actual received signals.

[0102] Step S14, based on the center position coordinates of each grid, and the time and channel gain of each LED light source transmitting the beacon signal, calculate the likelihood ratio between each actual received signal and the theoretical received signal of the beacon signal at the center position of each grid in the positioning area.

[0103] Specifically, in this embodiment, the calculation formula of the likelihood ratio is:

[0104]

[0105] in:

[0106]

[0107]

[0108] Where γ represents the likelihood ratio, M represents the number of LED light sources, i = 0, 1, ..., M-1, y i (k) represents the kth beacon signal emitted by the i-th LED light source and received by the positioning terminal, that is, the actual received signal of the kth beacon signal emitted by the i-th LED light source, P i represents the emission power of the i-th LED light source, s represents the grid number, It represents the overlapping time width between the expected pulse observation window and the actual observation window of the positioning terminal for the kth beacon signal emitted by the i-th LED light source at the grid s, T w Indicates the duration of a beacon signal within a beacon signal transmission time interval. represents the emission gain of the i-th LED light source in the direction pointing to the center of the s-th grid, Pa r(i,s) represents the receiving gain of the terminal located in the direction of the ith LED from the center of the sth grid. represents the distance between the i-th LED light source and the s-th grid, Represents the channel gain of the beacon signal emitted by the i-th LED light source propagating to the center of the s-th grid.

[0109] The calculation formula of the likelihood ratio outputs a likelihood ratio matrix composed of the likelihood ratios of each actual received signal and each grid s. It is used to characterize the theoretical receiving signal of the kth beacon signal emitted by the i-th LED light source reaching the s-th grid, y i (k) is the actual received signal of the positioning terminal for the kth beacon signal emitted by the ith LED light source. The actual received signal can be characterized by the same parameters, that is, the signal strength and arrival time can be used to characterize the signal.

[0110] Step S15: determining the target grid with the largest absolute value of the likelihood ratio according to the likelihood ratio calculation result, wherein the center position coordinates of the target grid are the position coordinates where the positioning terminal is most likely to be located.

[0111] Step S16, determining the coordinates of multiple vertex positions of the target mesh according to the center position coordinates of the target mesh.

[0112] It should be understood that when the center position coordinates and grid spacing of the target grid are known, the coordinates of each vertex position of the target grid can be determined, and specifically, the coordinates of the eight vertices of the target grid can be determined:

[0113]

[0114] in, Represents the target grid The center coordinates of .

[0115] Step S17, calculating the likelihood ratio between the actual received signal and the theoretical received signal of each vertex position for the beacon signal according to the coordinates of each vertex position, to obtain the likelihood ratio of each vertex position.

[0116] The method for calculating the likelihood ratio in this step is the same as the method for calculating the likelihood ratio in the above step S14, and will not be described in detail here.

[0117] Step S18: multiply the likelihood ratio of each vertex position by the coordinates of each vertex position, and then divide by the sum of the likelihood ratios of each vertex position to obtain the position coordinates of the positioning terminal.

[0118] That is, in this embodiment, after determining the most likely location of the positioning terminal through steps S13-S15, the position coordinates of the positioning terminal are not directly determined therefrom, but the similarity weighted method is used to further determine the final terminal location. Compared with the positioning method in the first embodiment, the accuracy of the indoor positioning method can be further improved.

[0119] In addition, it should be noted that in order to enable the positioning terminal to respond quickly, in the specific implementation, the following five types of preset parameters can be pre-stored in the memory of the positioning terminal, that is, some parameter information required by the positioning algorithm is pre-stored in the memory of the positioning terminal. The five types of preset parameters specifically include:

[0120] The first category: LED parameters, including the number M of LEDs contained in the positioning network device, the beacon signal wave i , LED coordinates The emission power P of the LED i , LED emission pattern Where i = 0, 1, ..., M-1, for example Figure 1 In the scenario shown, the input LED parameter can be M=4, and the coordinates of the 4 LEDs are:

[0121]

[0122]

[0123] The emission power of the 4 LEDs is P0=P1=P2=P3=3W; the emission direction diagram of the LED They are all Lambertian radiation models, namely: Where m represents the Lambertian radiation order, and θ represents the angle between the emission direction and the strongest emission direction of the LED center.

[0124] The second category: terminal parameters, which include the receiving pattern Pa of the terminal r , the legal position set Ω of the terminal, such as the receiving pattern of the terminal The legal position set of the terminal Ω = {z = h Pd},in, It represents the angle between the incident light direction and the normal direction of the receiving plane of the terminal PD detector; h Pd Indicates the height of the terminal PD detector receiving plane, for example, h Pd =0.3 m; where Ω = {z = h Pd} means z=h in XYZ coordinate system Pd A set of coordinate points on a plane;

[0125] The third category: grid division parameters of the positioning area. The parameters of the area to be positioned include the coordinates of the area vertices, the grid spacing (g x ,g y ,g z ), for example, the coordinates of the four vertices of the region are (4,4,h Pd ), (-4,4,h Pd ), (-4,-4,h Pd ), (4,-4,h Pd ), grid spacing (g x ,g y ,g z )=(0.2,0.2,0);

[0126] The fourth category: parameters of the positioning algorithm, which include position error tolerance ε and time domain search step factor α, for example, ε=0.1 m and α=0.1;

[0127] The fifth category: scenario learning parameters, which include the grid number j of the terminal preset during terminal learning, for example, j=0, that is, the terminal is placed at the center of the 0th grid for scenario learning.

[0128] Embodiment 3

[0129] Another aspect of the present invention is to provide an indoor positioning device. Figure 5 , used to locate the position of the positioning terminal in a preset positioning area indoors, the positioning area is pre-divided into a plurality of grids, a positioning network device is arranged indoors, the positioning network device includes at least one LED light source, the LED light source can periodically transmit a beacon signal to the positioning area in a pulse form, the indoor positioning device includes:

[0130] A signal receiving module 11 is used to obtain an actual received signal obtained by the positioning terminal receiving the beacon signal emitted by the LED light source;

[0131] A likelihood ratio calculation module 12, used to calculate the likelihood ratio between the actual received signal and the theoretical received signal for the beacon signal at the center position of each grid of the positioning area;

[0132] The indoor positioning module 13 is used to determine the target grid with the largest absolute value of the likelihood ratio according to the likelihood ratio calculation result, and determine the position of the positioning terminal according to the target grid with the largest absolute value of the likelihood ratio.

[0133] Furthermore, in some optional embodiments of the present invention, the indoor positioning device further includes:

[0134] The grid division module is used to divide the positioning area into grids and establish a corresponding relationship between the grids and the coordinates of their center positions, specifically for:

[0135] The closed area formed by connecting the vertex coordinates of the positioning area is divided into two parts according to the preset grid interval (g x ,g y ,g z ), from the vertex coordinates preset in the positioning area First, the grids are evenly divided and numbered along the X-axis, Y-axis, and Z-axis directions to obtain the numbered coordinates of each grid (s x ,s y ,s z ), s x 、s y 、s z are all natural numbers;

[0136] According to the numbered coordinates (s x ,s y ,s z ), calculate the center position coordinates of each grid and establishing a corresponding relationship between the grid and the coordinates of its center position;

[0137] in,

[0138] Furthermore, in some optional embodiments of the present invention, the indoor positioning device further includes:

[0139] The scene learning module is used to place the positioning terminal at the center of the specified grid for scene learning to learn the time and channel gain of each LED light source transmitting the beacon signal; specifically used for:

[0140] Place the positioning terminal at the center of the jth grid, and make the LED light source periodically transmit a beacon signal to the positioning terminal in a pulse form;

[0141] Obtaining the actual received signal of the positioning terminal for the beacon signal and arrival time

[0142] Calculate the distance between the jth grid center and each of the LED light sources and channel gain And calculate the time φ of each LED light source transmitting the kth beacon signal i (k); where

[0143]

[0144]

[0145] φ i (k) = φ i (0)+k×T I ;

[0146]

[0147] Where i represents the number of LED light sources, K represents the number of detections, k represents the number of beacon signals, k = 0, 1, ..., K-1, represents the channel gain of the beacon signal emitted by the i-th LED light source propagating to the center of the j-th grid, represents the distance from the kth grid center to the ith LED light source, φ i (k) represents the time when the i-th LED light source sends the k-th beacon signal, T I represents the emission time interval of the beacon signal, c represents the speed of light, represents the emission gain of the i-th LED light source in the direction pointing to the j-th grid center, Pa r (i,j) represents the receiving gain of the terminal located in the direction of the i-th LED light source from the j-th grid center. Represents the center position coordinates of the jth grid, represents the position coordinates of the i-th LED light source, φ i (0) represents the time when the i-th LED light source transmits the 0th beacon signal.

[0148] Furthermore, in some optional embodiments of the present invention, there are multiple LED light sources, and the signal receiving module is further used to receive each beacon signal emitted by each LED light source to obtain multiple actual received signals.

[0149] Furthermore, in some optional embodiments of the present invention, the likelihood ratio calculation module is also used to calculate the likelihood ratio between each actual received signal and the theoretical received signal of the beacon signal at the center position of each grid in the positioning area based on the center position coordinates of each grid, and the time and channel gain of each LED light source transmitting the beacon signal.

[0150] Furthermore, in some optional embodiments of the present invention, the calculation formula of the likelihood ratio is:

[0151]

[0152] in:

[0153]

[0154] Where γ represents the likelihood ratio, M represents the number of LED light sources, i = 0, 1, ..., M-1, y i (k) represents the kth beacon signal emitted by the i-th LED light source received by the positioning terminal, P i represents the emission power of the i-th LED light source, s represents the grid number, It represents the overlapping time width between the expected pulse observation window and the actual observation window of the positioning terminal for the kth beacon signal emitted by the i-th LED light source at the grid s, T w Indicates the duration of a beacon signal within a beacon signal transmission time interval. represents the emission gain of the i-th LED light source in the direction pointing to the center of the s-th grid, Pa r (i,s) represents the receiving gain of the terminal located in the direction of the ith LED from the center of the sth grid. represents the distance between the i-th LED light source and the s-th grid, Represents the channel gain of the beacon signal emitted by the i-th LED light source propagating to the center of the s-th grid.

[0155] Furthermore, in some optional embodiments of the present invention, the indoor positioning module includes:

[0156] A coordinate determination unit, used to determine the coordinates of a plurality of vertex positions of the target mesh according to the coordinates of the center position of the target mesh;

[0157] A likelihood ratio calculation unit, configured to calculate, according to the coordinates of each vertex position, a likelihood ratio between the actual received signal and a theoretical received signal of each vertex position for the beacon signal, to obtain a likelihood ratio of each vertex position;

[0158] The indoor positioning unit is used to multiply the likelihood ratio of each vertex position by the coordinates of each vertex position, and then divide the multiplication by the sum of the likelihood ratios of each vertex position to obtain the position coordinates of the positioning terminal.

[0159] The functions or operation steps implemented when the above modules and units are executed are generally the same as those in the above method embodiments, and will not be repeated here.

[0160] In summary, the indoor positioning device in the above-mentioned embodiment of the present invention calculates the likelihood ratio between the actual received signal of the positioning terminal and the theoretical received signal of the beacon signal at the center position of each grid pre-divided in the positioning area, finds the target grid with the largest absolute value of the likelihood ratio, and then determines the position of the positioning terminal according to the target grid with the largest absolute value of the likelihood ratio. This new indoor positioning method has been verified to be able to achieve a positioning accuracy of 0.5mm in an environment with a signal-to-noise ratio of 30dB, which is very close to the theoretical limit, breaking through the technical bottleneck of traditional indoor positioning accuracy and solving the technical problem of insufficient positioning accuracy in traditional indoor positioning methods based on visible light.

[0161] Embodiment 4

[0162] A fourth embodiment of the present invention further provides an indoor positioning system, the indoor positioning system comprising:

[0163] A positioning network device is arranged indoors, and the positioning network device includes at least one LED light source, and the LED light source can periodically transmit a beacon signal in a pulse form to a preset positioning area in the room, and the positioning area is pre-divided into a plurality of grids.

[0164] The positioning terminal is arranged indoors, and includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the indoor positioning method as described above is implemented to locate the position of the positioning terminal in the positioning area.

[0165] Among them, the processor in some embodiments can be a central processing unit (CPU), a controller, a microcontroller, a microprocessor or other data processing chip, which is used to run the program code stored in the memory or process data, such as executing an indoor positioning program.

[0166] Among them, the memory includes at least one type of readable storage medium, and the readable storage medium includes flash memory, hard disk, multimedia card, card-type memory (for example, SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. In some embodiments, the memory can be an internal storage unit of the positioning terminal, such as the hard disk of the positioning terminal. In other embodiments, the memory can also be an external storage device of the positioning terminal, such as a plug-in hard disk equipped on the positioning terminal, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. Further, the memory can also include both an internal storage unit and an external storage device of the positioning terminal. The memory can be used not only to store application software and various types of data installed in the positioning terminal, but also to temporarily store data that has been output or is to be output.

[0167] In summary, the indoor positioning system in the above-mentioned embodiment of the present invention calculates the likelihood ratio between the actual received signal of the positioning terminal and the theoretical received signal of the beacon signal at the center position of each grid pre-divided in the positioning area, finds the target grid with the largest absolute value of the likelihood ratio, and then determines the position of the positioning terminal based on the target grid with the largest absolute value of the likelihood ratio. This new indoor positioning method has been verified to be able to achieve a positioning accuracy of 0.5mm in an environment with a signal-to-noise ratio of 30dB, which is very close to the theoretical limit, breaking through the technical bottleneck of traditional indoor positioning accuracy and solving the technical problem of insufficient positioning accuracy in traditional indoor positioning methods based on visible light.

[0168] The embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the indoor positioning method as described above is implemented.

[0169] Those skilled in the art will appreciate that the logic and / or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable instructions for implementing logical functions, and may be embodied in any computer-readable storage medium for use by an instruction execution system, device, or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device, or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices, or apparatuses. For purposes of this specification, a "computer-readable storage medium" may be any device that can contain, store, communicate, propagate, or transmit a program for use by an instruction execution system, device, or apparatus, or in conjunction with such instruction execution systems, devices, or apparatuses.

[0170] More specific examples of computer-readable storage media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable storage medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or processing in another suitable manner as necessary, and then stored in a computer memory.

[0171] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or a combination thereof: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0172] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0173] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An indoor positioning method, characterized in that: The method is applied to a positioning terminal and used to locate the position of the positioning terminal in a positioning area preset indoors, wherein the positioning area is pre-divided into a plurality of grids, and a positioning network device is arranged indoors, wherein the positioning network device includes at least one LED light source, and the LED light source can periodically transmit a beacon signal to the positioning area in a pulse form, and the method includes: Receiving a beacon signal emitted by the LED light source to obtain an actual received signal; Calculating a likelihood ratio between the actual received signal and a theoretical received signal for the beacon signal at a center position of each grid of the positioning area; Determine the target grid with the largest absolute value of the likelihood ratio according to the likelihood ratio calculation result, and determine the position of the positioning terminal according to the target grid with the largest absolute value of the likelihood ratio; Before positioning, it also includes: Dividing the positioning area into grids, and establishing a corresponding relationship between the grids and the coordinates of their center positions; The steps of dividing the positioning area into grids and establishing a corresponding relationship between the grids and the coordinates of the central positions thereof include: The closed area formed by connecting the vertex coordinates of the positioning area is divided into two parts according to the preset grid interval (g x ,g y ,g z ), from the vertex coordinates preset in the positioning area First, the grids are evenly divided and numbered along the X-axis, Y-axis, and Z-axis directions to obtain the numbered coordinates of each grid (s x ,s y ,s z ), s x 、s y 、s z are all natural numbers; According to the numbered coordinates (s x ,s y ,s z ), calculate the center position coordinates of each grid and establishing a corresponding relationship between the grid and the coordinates of its center position; in, In addition, after the steps of dividing the positioning area into grids and establishing a corresponding relationship between the grids and the coordinates of the central positions thereof, the method further includes: Placing the positioning terminal at the center of the designated grid for scene learning to learn the time and channel gain of each LED light source transmitting the beacon signal; The step of placing the positioning terminal at the center of a designated grid for scene learning to learn the time and channel gain of each LED light source transmitting a beacon signal includes: Placing the positioning terminal at the center of the jth grid, and causing the LED light source to periodically transmit a beacon signal to the positioning area in a pulse form; Obtaining the actual received signal of the positioning terminal for the beacon signal and arrival time Calculate the distance between the jth grid center and each of the LED light sources and channel gain And calculate the time φ of each LED light source transmitting the kth beacon signal i (k); where f i (k)=φ i (0)+k×T I ; Where i represents the number of LED light sources, K represents the number of detections, k represents the number of beacon signals, k = 0, 1, ..., K-1, P i represents the emission power of the i-th LED light source, represents the channel gain of the beacon signal emitted by the i-th LED light source propagating to the center of the j-th grid, represents the distance from the jth grid center to the ith LED light source, φ i (k) represents the time when the i-th LED light source sends the k-th beacon signal, T I represents the emission time interval of the beacon signal, c represents the speed of light, represents the emission gain of the i-th LED light source in the direction pointing to the j-th grid center, Pa r (i,j) represents the receiving gain of the terminal located in the direction of the i-th LED light source from the j-th grid center. Represents the center position coordinates of the jth grid, represents the position coordinates of the i-th LED light source, φ i (0) represents the time when the i-th LED light source transmits the 0th beacon signal.

2. The indoor positioning method according to claim 1, characterized in that: The number of the LED light sources is multiple, and the steps of receiving the beacon signal emitted by the LED light sources and obtaining the actual received signal include: Each beacon signal emitted by each of the LED light sources is received to obtain a plurality of the actual received signals.

3. The indoor positioning method according to claim 2, characterized in that: The step of calculating the likelihood ratio between the actual received signal and the theoretical received signal for the beacon signal at the center position of each grid of the positioning area comprises: According to the center position coordinates of each grid, the time when each LED light source transmits the beacon signal, and the channel gain, the likelihood ratio between each actual received signal and the theoretical received signal of the beacon signal at the center position of each grid in the positioning area is calculated.

4. The indoor positioning method according to claim 3, characterized in that: The calculation formula of the likelihood ratio is: in: Wherein, γ represents the likelihood ratio, M represents the number of LED light sources, i=0, 1, ..., M-1, yi(k) represents the kth beacon signal emitted by the ith LED light source received by the positioning terminal, Pi represents the transmission power of the ith LED light source, s represents the grid number, represents the overlapping time width between the expected pulse observation window and the actual observation window of the positioning terminal for the kth beacon signal emitted by the i-th LED light source at the grid s, Tw represents the duration of the beacon signal within a beacon signal emission time interval, represents the emission gain of the i-th LED light source in the direction pointing to the center of the s-th grid, Pa r (i,s) represents the receiving gain of the terminal located in the direction of the ith LED from the center of the sth grid. represents the distance between the i-th LED light source and the s-th grid, Represents the channel gain of the beacon signal emitted by the i-th LED light source propagating to the center of the s-th grid.

5. The indoor positioning method according to any one of claims 1 to 4, characterized in that: The step of determining the position of the positioning terminal according to the target grid having the largest absolute value of the likelihood ratio comprises: Determine the coordinates of multiple vertex positions of the target mesh according to the center position coordinates of the target mesh; Calculating, according to the coordinates of each vertex position, a likelihood ratio between the actual received signal and a theoretical received signal at each vertex position for the beacon signal, to obtain a likelihood ratio of each vertex position; The likelihood ratio of each vertex position and the coordinates of each vertex position are multiplied and then divided by the sum of the likelihood ratios of each vertex position to obtain the position coordinates of the positioning terminal.

6. An indoor positioning device, characterized in that: The method for indoor positioning according to claim 1 is used to implement the method, applied to a positioning terminal, and used to locate the position of the positioning terminal in a positioning area preset indoors, wherein the positioning area is pre-divided into a plurality of grids, and a positioning network device is arranged indoors, wherein the positioning network device includes at least one LED light source, and the LED light source can periodically transmit a beacon signal to the positioning area in a pulse form, wherein the device includes: A signal receiving module, used to receive the beacon signal emitted by the LED light source and obtain an actual received signal; A likelihood ratio calculation module, used to calculate the likelihood ratio between the actual received signal and the theoretical received signal for the beacon signal at the center position of each grid of the positioning area; The indoor positioning module is used to determine the target grid with the largest absolute value of the likelihood ratio according to the likelihood ratio calculation result, and determine the position of the positioning terminal according to the target grid with the largest absolute value of the likelihood ratio.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the indoor positioning method as described in any one of claims 1 to 5 is implemented.

8. An indoor positioning system, characterized in that: The indoor positioning system comprises: A positioning network device is arranged indoors, and the positioning network device includes at least one LED light source, and the LED light source can periodically transmit a beacon signal in a pulse form to a preset positioning area in the room, and the positioning area is pre-divided into a plurality of grids. A positioning terminal is arranged indoors, and the positioning terminal includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the indoor positioning method according to any one of claims 1 to 5 is implemented to locate the position of the positioning terminal in the positioning area.

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