AU2021105056A4 - Visible light combined azimuth beam positioning method cater to single access point - Google Patents
Visible light combined azimuth beam positioning method cater to single access point Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/16—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using electromagnetic waves other than radio waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/20—Instruments for performing navigational calculations
- G01C21/206—Instruments for performing navigational calculations specially adapted for indoor navigation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
- G01S1/70—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using electromagnetic waves other than radio waves
- G01S1/703—Details
- G01S1/7032—Transmitters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
- H04B10/114—Indoor or close-range type systems
- H04B10/116—Visible light communication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/501—Structural aspects
- H04B10/502—LED transmitters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0408—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas using two or more beams, i.e. beam diversity
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/30—Services specially adapted for particular environments, situations or purposes
- H04W4/33—Services specially adapted for particular environments, situations or purposes for indoor environments, e.g. buildings
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
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- Automation & Control Theory (AREA)
- Optical Communication System (AREA)
Abstract
The invention relate to the technical field of visible light positioning, in particular to a visible
light combined azimuth beam positioning method cater to single access point, which comprises
the following step of: realizing the positioning space of a mobile terminal under the scene of
providing a single optical access point with multi-directional optical beams. According to the
invention, only one single access point is needed in an application scene, and the single access
point provides multi-directional optical beams, and then the azimuth scanning, measurement
and estimation of the mobile terminal are carried out based on the multi-beam visible light
wireless access point. According to the basic azimuth information of the mobile terminal and
the coarse positioning area information of the radial distance, finally, by means of the position
fingerprint database associated with the visible light wireless access point, the matching degree
of the position fingerprint in the coarse positioning area and the signal intensity corresponding
to the main beam actually measured by the mobile terminal subsystem is screened, and the
candidate spatial location corresponding to the location fingerprint with the highest matching
degree is used as the optimized location of the mobile terminal.
16/16
Basic spatial orientation information
digital to analog conversion
Frequency up converter Mobile terminal subsystem
transmitting module
Powei amplifier
Transmitting antenna
-% - -- - -- -- - -- -
radio-frequency signal
Fig.21
Description
16/16
Basic spatial orientation information
digital to analog conversion
Frequency up converter Mobile terminal subsystem transmitting module Powei amplifier
Transmitting antenna -% - -- - -- -- - -- -
radio-frequency signal
Fig.21
Visible light combined azimuth beam positioning method cater to single access
point
The invention relate to the technical field of visible light positioning, in particular to a
visible light combined azimuth beam positioning method cater to single access point.
The visible light positioning technology loads the visible light positioning signal on the
biasing device current of LED light source by using the existing LED lighting
infrastructure, thus providing universal lighting for users and wireless positioning
coverage. However, the existing visible light positioning technical scheme generally
requires multiple LED position reference light sources to serve the visible light
positioning scheme at the same time. The representative research schemes include: (1)
Monsen Kavehrad team of The Pennsylvania State University proposed and further
improved the trilateral positioning scheme based on received signal intensity information
in the article Indoor Positioning Algorithm Using Light-Emitting Diode Visible Light
Communications. The basic idea of the scheme is to calculate the relative distance
between the receiver and the three position reference light sources according to the
optical signal power from the three position reference light sources detected by the
optical receiver, and then list the equations of the three distance relationships. Finally, the
two-dimensional or even three-dimensional spatial position coordinates of the optical
receiver are solved. (2) In the article Indoor Location Using White LEDs, J. Armstrong
team of Monash University, Australia, demonstrated a position estimation scheme that
estimated the relative distance between the receiver and two LED light sources by means of two LED light sources transmitting the same single-frequency signal. The limitation of the above scheme is that once the visible light positioning scene cannot provide two, three or even more reference light sources for visible light positioning, the above positioning scheme cannot work normally, and finally the mobile terminal cannot know its own spatial position information through the above traditional visible light positioning.
It must be pointed out that some international research teams have tried to realize the
position estimation of mobile terminals under the single position light source
configuration. Particularly, in the article Indoor Location Estimation Based on LED
Visible Light Communication Using Multiple Optical Receivers, the research team of
Sang-Kook Han, Yonsei University, Korea, proposed to construct a multi-optical receiver
by means of multiple photodetectors with relatively fixed position relationship, and then
calculate the spatial coordinate position of the center of the optical receiver according to
the relatively fixed spatial position relationship between photodetectors. It is not difficult
to find that although the above scheme can be applied to the single light source scene, it
needs to significantly increase the number of photodetectors on the optical receiver,
which inevitably increases the engineering cost and implementation complexity of the
optical receiver.
The future commercial visible light positioning system must be suitable for various
application scenarios, especially those with limited number of light sources. In addition,
this kind of commercial visible light positioning system must minimize the implementation cost of the mobile terminal, and avoid the significant increase of the project cost caused by the introduction of multiple photodetectors.
In order to effectively cope with the above challenges, effectively improve the
adaptability of the visible light positioning technology scheme to the limited scenes of
light source infrastructure, and at the same time fully avoid the excessive rise of receiver
complexity and cost caused by adopting multiple photodetectors, the industry urgently
needs a joint design scheme that can meet the strict constraints of visible light source
infrastructure and strict receiver complexity and low cost objectives at the same time, so
as to effectively promote the practicality, industrialization and scale of the visible light
positioning technology scheme.
The invention provide a visible light combined azimuth beam positioning method cater to
single access point, which overcome the defects of the prior art. In an application scene,
only one single access point (i. e., a single visible light positioning light source) is
needed, the single access point provide multi-directional optical beams, and then the
azimuth scanning, measurement and estimation of the mobile terminal are carried out
based on the multi-beam visible light wireless access point, so that the basic azimuth
information of the mobile terminal is obtained, and the azimuth radius information (radial
distance) of the mobile terminal is obtained by combining the traditional omnidirectional
Lambert optical beams, and the mobile terminal is further smaller. Finally, with the help
of the location fingerprint database associated with the visible light wireless access point,
the location fingerprint in the coarse positioning area and the signal intensity corresponding to the main beam measured by the mobile terminal subsystem are screened for matching degree, and the candidate spatial position corresponding to the location fingerprint with the highest matching degree is taken as the optimized mobile terminal positioning position, thus obtaining the precise spatial position of the mobile terminal.
The technical scheme of the invention is realized by the following measures: a visible
light combined azimuth beam positioning method cater to single access point, which
comprises the following steps:
Step 1, the positioning controller module in the visible light access point subsystem
periodically constructs a time-division beam activation signal, which carries positioning
data frame structures, each positioning data frame structure comprises frame headers and
loads, wherein the frame header internally contains one synchronization sequence for
synchronizing with the mobile terminal subsystem, and the load internally contains
azimuth beam activation state information associated with each azimuth beam and
omnidirectional beam. Each positioning data frame structure only has an associated
bearing space of the optical beam to be activated, which contains one optical beam
identifier associated with the activated optical beam, and the visible light access point
subsystem sends positioning data frame.
Step 2, loading the frame header of the positioning data frame in the visible light access
point subsystem to all LED light sources of LED lighting facilities providing multi
directional optical beams, wherein the LED lighting facilities providing multi-directional
optical beams are the only visible light sources of application scenes.
Step 3, the visible light access point subsystem loads the internal load of each part of the
positioning data frame to each azimuth LED light source of the LED lighting facility
providing multi-directional optical beams, each LED light source is driven to light up by
the light source driving module of the visible light access point subsystem and loads the
corresponding beam activation state bearing information, and loads its internal load to the
light source driving module input terminals of all optical beams continuously and in
parallel along with each positioning data frame, and all azimuth beams and
omnidirectional beams sequentially send their own optical beam identifications (Optical
Beam ID).
Step 4, the mobile terminal subsystem receives the optical beam identification of the
visible light signal.
Step 5, the mobile terminal subsystem measures the load signal intensity of the optical
beam identification and captures the strongest optical beam identification information
(Optical Beam ID).
Step 6, the mobile terminal subsystem searches the optical beam spatial association sector
list to obtain the basic spatial orientation information of the optical beam spatial sector
where the mobile terminal is located.
Step 7, the omnidirectional high-power LED light source or LED light source sub-array
in the normal direction (the direction is perpendicular to the positioning area below the
visible light emitter) of the LED lighting facility (visible light emitter) sends out an
omnidirectional visible light positioning auxiliary signal, and the mobile terminal subsystem captures the omnidirectional positioning auxiliary light signal and measures the signal intensity.
Step 8, according to the measured signal intensity, the radial distance between the LED
lighting facility and the mobile terminal is obtained.
Step 9, the mobile terminal subsystem determines the basic spatial position of the mobile
terminal according to the obtained basic spatial orientation information and radial
distance of the mobile terminal.
The following is a further optimization or/and improvement of the technical scheme of
the above invention:
The precise spatial position of the mobile terminal is obtained according to the following
method:
The mobile terminal subsystem captures the strongest N strongest beam azimuth beam
intensity values. Then, the two-dimensional spatial position fingerprint records stored in
the fingerprint database and respectively associated with the N strongest beam azimuth beams
are called by the position fingerprint matching module in the visible light access point
subsystem. In the fingerprint records of N strongest beam, the random iterative optimization
search of position fingerprint matching is carried out near the basic spatial position of the
mobile terminal. The visible light access point subsystem sends the N strongest beam azimuth
beams to the mobile terminal. The mobile terminal subsystem replaces the basic spatial
position information of the mobile terminal with the position information obtained by random iterative operation of fingerprint matching to obtain the precise spatial position of the mobile terminal.
The random iterative optimization search comprises the following steps: (1) Performing
mean square operation on the deviation between the signal intensity in the fingerprint
records of the N strongest beam and the azimuth beam intensity values of the N strongest beam fed
back by the mobile terminal subsystem to obtain the root mean square error RMS error
candidate position between them. (2) Performing mean square operation on the deviation
between the signal intensity of the basic spatial position of the mobile terminal fed back
by the mobile terminal subsystem in the fingerprint records of the N strongest beam and the
azimuth beam intensity values of the N strongest beam fed back by the mobile terminal
subsystem to obtain the root mean square error RMS error - current position. (3) If RMS error
candidate position <PMS error - current position, replace the current position with candidate position.
If PMS error- candidate position ;> RMS error - current position, keep the current position without
updating and enter the next iteration until the termination condition of stochastic iterative
optimization search is reached.
The above termination conditions are one of the following conditions: (1) The number of
iterations reaches the preset maximum value. (2)RMS error - current position is less than the
preset deviation threshold. (3) The time consumption of stochastic iterative optimization
search exceeds the preset time consumption threshold.
The spatial structure of the optical beam emission lampshade of the LED lighting facility
providing multi-directional optical beams is hemispherical or ellipsoidal or conical at the
upper part and cylindrical at the lower part.
According to the method, the position estimation of the mobile terminal is realized only
through one single visible light access point and less necessary calculations, and the
natural limitations of a series of visible light positioning schemes which rely on a
plurality of visible light emitters (i.e., a plurality of distributed light sources) and a
plurality of receivers (at least a plurality of photodetectors) are objectively overcome.
Fig. 1 is a flow chart of the visible light combined azimuth beam positioning method
cater to single access point according to the present invention.
Fig. 2 is a flow chart of obtaining the precise spatial position of the mobile terminal
according to the present invention.
Fig. 3 is a logic block diagram of random iterative optimization search according to the
present invention.
Fig. 4 is an application scenario diagram of the spatial structure of the visible light access
point subsystem providing multi-directional optical beams is hemispherical (three
dimensional hemispherical).
Fig. 5 is an application scenario diagram of the ellipsoidal (three-dimensional ellipsoidal)
spatial structure of the visible light access point subsystem providing multi-directional
optical beams.
Fig. 6 is an application scenario diagram showing that the spatial structure of the visible
light access point subsystem providing multi-directional optical beams is conical at the upper part and cylindrical at the lower part (approximately conical cylinder type combination).
Fig. 7 is a top view of the spatial structure of the hemispherical (three-dimensional
hemispherical) visible light access point subsystem.
Fig. 8 is a front view of the spatial structure of the hemispherical (three-dimensional
hemispherical) visible light access point subsystem.
Fig. 9 is a general view of the spatial structure of the hemispherical (three-dimensional
hemispherical) visible light access point subsystem.
Fig. 10 is a top view of the spatial structure of the ellipsoidal (three-dimensional
ellipsoidal) visible light access point subsystem.
Fig. 11 is a front view of the spatial structure of the ellipsoidal (three-dimensional
ellipsoidal) visible light access point subsystem.
Fig. 12 is a general view of the spatial structure of the ellipsoidal (three-dimensional
ellipsoidal) visible light access point subsystem.
Fig. 13 is a top view of the spatial structure of the visible light access point subsystem in
the shape of an upper cone and a lower cylinder (approximately conical cylinder type
combination).
Fig. 14 is a front view of the spatial structure of the visible light access point subsystem
in the shape of an upper cone and a lower cylinder (approximately conical cylinder type
combination).
Fig. 15 is a general perspective view of the spatial structure of the visible light access
point subsystem in the shape of an upper cone and a lower cylinder (approximately
conical cylinder type combination).
Fig. 16 is an overall structure diagram of the device according to the present invention.
Fig. 17 is a block diagram of the visible light access subsystem receiving module.
Fig. 18 is a control block diagram of the positioning controller module.
Fig. 19 is a control block diagram of the light source driving module.
Fig. 20 is a block diagram of the mobile terminal subsystem.
Fig. 21 is a block diagram of the transmission module of the mobile terminal subsystem.
The codes in the figures are: 1 - LED lighting facility, 2 - mobile receiving terminal, 3
receiving antenna.
The present invention is not limited by the following embodiments, and the specific
implementation mode can be determined according to the technical scheme and the actual
situation of the present invention.
In the present invention, for the convenience of description, the description of the relative
positional relationship of each component is described according to the layout mode in
Fig. 1 of the specification, for example, the positional relationship of front, back, upper,
lower, left and right is determined according to the layout direction in Fig. 1 of the
specification.
In the present invention, the terms "first", "second", "third", etc. are only used for
distinguishing descriptions, for example, "first amplifier" only refers to an amplifier, and
cannot be understood as indicating or implying relative importance.
The mobile terminal of the present invention can be known optical signal receiving
equipment such as an optical receiver and a photodetector.
According to the invention, only one single access point (i.e. a single visible light
positioning light source) is needed, and at the same time, multiple access points (i.e. a
traditional multi-visible light positioning light source) can be supported in a backward
compatible manner, and respective beams of directional or relatively directional
subarrays of the access points respectively point to different spatial directions.
The invention will be further described with reference to the following embodiments:
Embodiment 1: as shown in Fig. 1, Fig. 4, Fig. 5, Fig. 6, a visible light combined azimuth
beam positioning method cater to single access point, which includes the following
steps:
Step 1, the positioning controller module in the visible light access point subsystem
periodically constructs a time-division beam activation signal, which carries positioning
data frame structures, each positioning data frame structure comprises frame headers and
loads, wherein the frame header internally contains one synchronization sequence for
synchronizing with the mobile terminal subsystem, and the load internally contains
azimuth beam activation state information associated with each azimuth beam and
omnidirectional beam. Each positioning data frame structure only has an associated
bearing space of the optical beam to be activated, which contains one optical beam
identifier associated with the activated optical beam, and the visible light access point
subsystem sends positioning data frame.
Assuming that the number of azimuth beams is N, considering the existence of
omnidirectional optical beams, the number of all optical beams involved in the
positioning process is (N+1). Therefore, each positioning data frame sent sequentially
contains (N+1) reserved activation state information bearing spaces. To realize the
sequential activation of each optical beam and send corresponding optical beam
identification (i.e., Optical Beam ID) information, only the associated bearing space of
the optical beam to be activated exists in each positioning data frame structure, and the
associated bearing space contains the associated Optical Beam ID. To suppress the
activation of the remaining optical beams, all the associated bearing spaces of the
remaining optical beams are set to zero.
Step 2, loading the frame header of the positioning data frame in the visible light access
point subsystem to all LED light sources of LED lighting facility 1 providing multi- directional optical beams, wherein the LED lighting facility 1 providing multi-directional optical beams are the only visible light sources of application scenes.
Step 3, the visible light access point subsystem loads the internal load of each part of the
positioning data frame to each azimuth LED light source of the LED lighting facility 1
providing multi-directional optical beams, each LED light source is driven to light up by
the light source driving module of the visible light access point subsystem and loads the
corresponding beam activation state bearing information, and loads its internal load to the
light source driving module input terminals of all optical beams continuously and in
parallel along with each positioning data frame, and all azimuth beams and
omnidirectional beams sequentially send their own optical beam identifications (Optical
Beam ID).
Step 4, the mobile terminal subsystem receives the optical beam identification of the
visible light signal.
Step 5, the mobile terminal subsystem measures the load signal intensity of the optical
beam identification and captures the strongest optical beam identification information
(Optical Beam ID).
Step 6, the mobile terminal subsystem searches the optical beam spatial association sector
list to obtain the basic spatial orientation information of the optical beam spatial sector
where the mobile terminal is located.
Step 7, the omnidirectional high-power LED light source or LED light source sub-array
in the normal direction (the direction is perpendicular to the positioning area below the visible light emitter) of the LED lighting facility (visible light emitter) sends out an omnidirectional visible light positioning auxiliary signal, and the mobile terminal subsystem captures the omnidirectional positioning auxiliary light signal and measures the signal intensity.
Step 8, the mobile terminal subsystem obtains the radial distance between the visible light
emitter and the mobile terminal according to the omnidirectional optical beam
propagation model and the measured signal intensity.
The omnidirectional optical beam propagation model is known in the prior art.
Step 9, the mobile terminal subsystem determines the basic spatial position of the mobile
terminal according to the obtained basic spatial orientation information and radial
distance of the mobile terminal.
That is, according to the basic spatial orientation information of the sector where the
mobile terminal is located, it is correspondingly known that the mobile terminal is
basically located in the specific area covered by the sector (or that the optical access point
is on the direction axis led out by the orientation). According to the radial distance
between the mobile terminal and the visible light emitter, it can be known that the mobile
terminal is basically located on the ring with the optical access point as the center and the
radial distance as the radius. Therefore, it is basically determined that the rough
positioning position (basic spatial position) of the mobile terminal is at the intersection of
the azimuth ray and the circular ring or a local small area around the position.
Embodiment 2: as shown in Figs. 2 and 3, as an optimization of embodiment 1, the
positioning accuracy of the mobile terminal can be enhanced by means of local
fingerprint positioning on the basis of determining the basic spatial position of the mobile
terminal.
Specifically, the mobile terminal subsystem sends the following data to the uplink
receiving module in the visible light access point subsystem through its own uplink (the
lowest rate required by the uplink is very low, even as low as the order of Kbps, which
can be met by most low-cost commercial wireless modules, so its implementation can be
but not limited to WiFi, infrared wireless transmission, ZigBee, etc.).
Specific data contents include: (1) Basic spatial location information of mobile terminal.
(2) The mobile terminal subsystem captures the strongest N strongest beam (the typical values
of N strongest beam are 1,2,3,4).
Invoking two-dimensional spatial position fingerprint records stored in a fingerprint
database and respectively associated with N strongest beam azimuth beams through the
position fingerprint matching module in the visible light access point subsystem. In the
fingerprint records of the N strongest beam, the random iterative optimization search of
position fingerprint matching is carried out near the basic spatial position of the mobile
terminal (assuming that the search area radius is R fingerprint search).
The random iterative optimization search comprises the following steps: (1) Performing
mean square operation on the deviation between the signal intensity in the fingerprint
records of the N strongest beam and the azimuth beam intensity values of the N strongest beam fed back by the mobile terminal subsystem to obtain the root mean square errorR Serror candidate position between them. (2) Performing mean square operation on the deviation between the signal intensity of the basic spatial position of the mobile terminal fed back by the mobile terminal subsystem in the fingerprint records of the N strongest beam and the azimuth beam intensity values of the N strongest beam fed back by the mobile terminal subsystem to obtain the root mean square error RMS error - current position. (3) If RMS error candidate position <P2MS error - current position, replace the current position with candidate position.
If PMS error- candidate position ;> RMS error - current position, keep the current position without
updating and enter the next iteration until the termination condition of stochastic iterative
optimization search is reached.
The termination condition is one of the following conditions: (1) The number of iterations
reaches the preset maximum value. (2) RMS error - current position is less than the preset
deviation threshold. (3) The time consumption of stochastic iterative optimization search
exceeds the preset time consumption threshold.
After the iterative optimization search is terminated, the visible light access point
subsystem sends the N strongest beam azimuth beams to the mobile terminal. The mobile
terminal subsystem replaces the basic spatial position information of the mobile terminal
with the position information obtained by random iterative operation of fingerprint
matching to obtain the precise spatial position of the mobile terminal.
As shown in Figs. 4 to 6, the spatial structure of the optical beam emission lampshade of
the LED lighting facility 1 for providing multi-directional optical beams is hemispherical
or ellipsoidal or conical at the upper part and cylindrical at the lower part.
As shown in Fig. 4, Fig. 7 to Fig. 9, a optical beam emitting lampshade with a
hemispherical spatial structure (three-dimensional hemispherical structure) is installed at
the center of the hemispherical substrate spatial structure by installing a high-power LED
light source capable of emitting directional spatial optical beams or a small-size light
source array composed of a plurality of low-power LEDs, and the substrate spatial
structure is spliced by two-dimensional substrates with regular small sizes facing
different directions (in other words, the three-dimensional hemispherical substrate spatial
structure is actually spliced by a plurality of regular small-size two-dimensional
substrates). In this way, although a plurality of LED light sources or light source arrays
on the emitter (LED lighting facility 1 providing multi-directional optical beams) share
the same hemispherical light source emitter structure (optical beam emitting lampshade),
after the light sources are simultaneously lit, each azimuth sub-area of the positioning
service area can be respectively lit by means of the comprehensive design of directional
beams and different spatial orientations.
Although in order to ensure that the covered area provides continuous illumination
coverage (avoiding dark areas or areas without illumination coverage), small-sized areas
(also called sectors) covered by adjacent optical beams must tolerate a small amount of
overlap to cover the edge areas. However, for most sectors, once the mobile terminal
enters the corresponding area, the intensity of the positioning optical signal captured by
the mobile terminal from the associated directional beam will be much higher than the
intensity of the leaked optical signal of the associated optical beam of the adjacent sector.
Therefore, the mobile terminal subsystem can quickly obtain the basic spatial orientation
information of the sector where the mobile terminal is located by demodulating the
Optical Beam ID information carried by the strongest optical beam signal in the sector,
and searching the stored optical sector azimuth list.
The above-mentioned sector division mode only depends on the orientation of each bit
optical beam to carry out differentiated lighting division. Therefore, in order to improve
the fineness of sector division, it is necessary to increase the number of all LED light
source orientations. In fact, under the condition of the same pitch angle (corresponding to
the same horizontal cross-section boundary on the three-dimensional spatial structure),
the number of available orientations is limited. With the decrease of azimuth interval,
engineering challenges such as difficulty in assembling access points and effective heat
dissipation will be highlighted. In order to take into account the above challenges and
reduce the sector size at the same time, two-layer, three-layer or even multi-layer LEDs
with different orientations can be arranged under different pitch angles on the spatial
structure of the three-dimensional hemispherical substrate (corresponding to different
horizontal cross-section boundaries on the three-dimensional spatial structure). In this
way, the sector division of visible light positioning coverage area includes not only the
division of azimuth dimension, but also the division of radial distance dimension
(different radial distances correspond to different pitch angles on the spatial structure of
three-dimensional hemispherical substrate). The segmentation of two dimensions greatly
increases the fineness of sector segmentation.
The above three-dimensional hemispherical structure can naturally match the square
coverage area or the coverage area with larger size. However, considering that the
application of visible light positioning must adapt to various indoor scenes, the coverage area of typical or most indoor scenes is rectangular. In this kind of typical scene, if the above-mentioned three-dimensional hemispherical construction mode is applied only, it is likely that the sector segmentation precision in the long-axis direction of the coverage area is insufficient, but the sector segmentation precision in the short-axis direction of the coverage area is dense, and even some azimuth beams directly point to the wall surface instead of the coverage receiving surface, thus losing the meaning of sector segmentation.
Therefore, on the basis of the above-mentioned three-dimensional hemispherical
structure, we must consider the geometric characteristics of the typical indoor scene
coverage area, and propose a three-dimensional ellipsoidal structure (the spatial structure
is ellipsoidal, see Fig. 10 to 12). The long axis direction of this structure should be
consistent with the long axis direction of the coverage area, and accordingly its short axis
direction should be consistent with the short axis direction of the coverage area. At the
same time, the ratio of its own long axis to its own long axis should be basically equal to
that of the room. In this way, the distribution of optical azimuth beams is relatively dense
in the long axis direction of the three-dimensional ellipsoidal structure, and relatively
sparse in the short axis direction of the three-dimensional ellipsoidal structure. Therefore,
the adaptation between the three-dimensional spatial structure of the visible light access
point and the coverage area is realized as a whole.
For some scenes with low demand for positioning accuracy, it is likely that there is no
need to arrange 2-layer, 3-layer or even multi-layer LEDs with different orientations
under different pitch angles on the spatial structure of the three-dimensional
hemispherical substrate (corresponding to different horizontal cross-section boundaries on the three-dimensional spatial structure). The number of azimuth beams arranged in different azimuth will also be reduced.In this way, the above-mentioned three dimensional hemispherical structure or three-dimensional ellipsoidal structure will degenerate to the approximate conical cylinder structure (the spatial structure is conical at the upper part and cylindrical at the lower part, see Fig. 13 to 15). The number of sectors divided in the coverage area is also significantly reduced, and the geometric size of the sectors is also increased.
Embodiment 3: as shown in Fig. 16, a device for implementing the visible light combined
azimuth beam positioning method cater to single access comprises one visible light
access point subsystem and one mobile terminal subsystem, wherein the visible light
access point subsystem comprises one uplink receiving module, one positioning
controller module and one light source driving module, and the positioning controller
module and the light source driving module are electrically connected in sequence. The
mobile terminal subsystem includes photodetector, analog-to-digital conversion module,
first amplifier, coupler, synchronization module, comparator, memory, discriminator and
uplink transmission module. Photodetector is electrically connected with analog-to-digital
conversion module, the first amplifier is electrically connected with the coupler, which is
electrically connected with the synchronization module and comparator. The
synchronization module, comparator and memory are electrically connected with the
discriminator, and the discriminator is electrically connected with the uplink transmission
module in sequence.
The visible light access point subsystem: the positioning controller module generates a
periodic time-division beam activation signal and loads the bearing subspace contents
associated with each optical beam in the internal load into the drive circuits of the light
source driving modules associated with each azimuth beam and omnidirectional beam
respectively, lights up the light source and loads the corresponding beam activation state
information bearing information through the DC biasing device provided by the DC
driving ports of each drive circuit. All azimuth beams and omnidirectional beams send
their respective Optical Beam ID to the mobile terminal subsystem in turn.
Mobile terminal subsystem: perform synchronous correlation operation on the known and
saved synchronization sequence (which is the same as the synchronization sequence
contained in the frame header of positioning data frame) and the visible light positioning
signal output by the mobile receiving terminal 2, determine the starting time of
positioning data frame, then detect the load signal intensity of Optical Beam ID
associated with each azimuth beam according to time division multiplexing mode, and
determine the Optical Beam ID of the spatial azimuth where the mobile terminal is
located. Further, the optical sector azimuth list stored in the mobile terminal subsystem is
searched, the basic spatial orientation information of the sector where the mobile terminal
is located is determined, the omnidirectional positioning auxiliary optical signal is
captured, and the measured intensity of the received signal is measured. According to the
known visible light signal propagation model of omnidirectional optical beam, the radial
distance between visible light emitter and mobile terminal is calculated.According to the
obtained spatial orientation and radial distance of the mobile terminal.
As shown in Figs. 17 to 19, in the visible light access point subsystem:
The uplink receiving module (i.e., receiving module) is used to receive the basic spatial
location information transmitted from the mobile terminal subsystem.
The positioning controller module is used for generating a periodic time-division beam
activation signal, which carries a fixed-size positioning data frame structure, and each
positioning data frame structure mainly comprises two parts: frame header and load,
wherein the frame header contains a synchronization sequence for realizing
synchronization with the synchronous positioning module of the mobile terminal
subsystem, and the load contains azimuth beam activation state information associated
with each azimuth beam and the bottom omnidirectional beam.
The light source driving module is used for lighting the light source loaded with the
corresponding beam activation state bearing information, and all azimuth beams and
omnidirectional beams sequentially send their respective Optical Beam ID.
As shown in Figs. 20 to 21, in the mobile terminal subsystem:
The photodetector is used for detecting the visible light signal emitted by the light source
emitter (the LED lighting facility 1 providing multi-directional optical beams) and
reducing it into an electrical signal.
The analog-to-digital conversion module is used for converting analog signals into digital
signals.
The first amplifier is used for amplifying the received weak digital signal to improve the
output signal-to-noise ratio.
The coupler is used to divide one digital signal into two identical digital signals for
transmission, one of which enters the synchronization module for synchronization
processing to determine the beam Optical Beam ID of the spatial orientation where the
mobile terminal is located, and the other of which enters the comparator to output the
strongest Optical Beam ID load signal intensity.
The memory is used to synchronize the beam activation signal received by the
photodetector and save the synchronization sequence (which is the same as the
synchronization sequence contained in the frame header of the positioning data frame).
The discriminator is used for performing synchronous correlation operation on the beam
activation signal output by the amplifier and the positioning signal stored in the memory,
judging the time corresponding to the peak output of the correlation operation and
determining the starting time of the positioning data frame.
The optical beam spatial association sector list is used to store the optical beam spatial
association sector list, and quickly obtain the basic spatial orientation information of the
sector where the mobile terminal is located.
As shown in Fig. 18, the positioning controller module includes one controller, one status
register, one data register and one data shift register, which are electrically connected in
sequence.
As shown in Fig. 19, the light source drive circuit module includes one DC source and
one biasing device, which are electrically connected in sequence.
As shown in Fig. 17, the uplink receiving module of the visible light access point
subsystem includes one receiving antenna 3, one low noise amplifier, one frequency
down-converter and one analog-to-digital converter. The receiving antenna 3 receives the
radio frequency signal from the transmitting module of the mobile terminal subsystem,
obtains the radio frequency signal of this frequency band through a band-pass filter,
filters out the environmental interference noise by an amplifier, amplifies the radio
frequency signal, and loads the electrical signal carrying identification information to a
digital-to-analog converter through a low-pass filter.
As shown in fig. 21, the uplink transmitting module of the mobile terminal subsystem
includes one digital-to-analog conversion module, one frequency up-converter, one
power amplifier and one transmitting antenna. The digital-to-analog conversion module
converts the received digital signals into analog signals and transmits them to the
frequency up-converter, which is amplified by the power amplifier and then loaded to the
transmitting antenna, and sends radio frequency signals to the receiving module of the
visible light access point subsystem.
According to the invention, the visible light wireless access point is constructed by
utilizing the visible optical beams of different spatial orientations pointed by the LED
lighting facility 1 providing multi-directional optical beams, and then the azimuth
scanning, measurement and estimation of the mobile terminal are carried out based on the
multi-beam visible light wireless access point, and the small-size coarse positioning area of the mobile terminal is further obtained by combining the azimuth radius information of the mobile terminal obtained by the traditional omnidirectional Lambert optical beams.
Finally, with the help of the position fingerprint database associated with the visible light
wireless access point, the matching degree of the position fingerprint in the coarse
positioning area and the signal intensity corresponding to the main beam measured by the
mobile terminal is screened, and the candidate spatial position corresponding to the
position fingerprint with the highest matching degree is taken as the optimized mobile
terminal positioning position.
Different from the traditional visible light positioning scheme based on distributed multi
light source configuration, the visible light combined azimuth beam positioning method
cater to single access can significantly reduce the number of necessary position reference
light sources. Generally speaking, from the common three groups of light sources (which
require full separation of spatial positions among light sources) to only one group of light
sources (namely, a group of LED lighting facilities 1 providing multi-directional optical
beams), it is a single visible light access point from the perspective of visible light
positioning.
The visible light combined azimuth beam positioning method for a single access point
can be applied to various complex scenes, objectively breaks through the technical
paradigm of the existing visible light positioning scheme, and has many significant
technical advantages, which mainly include: (1) The positioning performance is strong in
extensibility, and based on the proposed combined azimuth beam positioning scheme, the
matching calculation operation of the local fingerprint position information of the sector where the mobile terminal is located is carried out in combination with the existing mature fingerprint positioning scheme, so that the finer terminal position information is finally matched and screened quickly with moderate or even smaller matching calculation cost. (2) The scene adaptability is strong, and it can be applied to scenes with only a single set of light sources and high-precision positioning by means of visible light signals. (3) The cost budget is low, which can be applied to the scene where the cost of visible light positioning is sensitive. (4) The scene is friendly, which can be applied to the scene where the owner or property at the location of the access point is difficult to coordinate and communicate, and it is difficult to add light source infrastructure. (5) The energy use efficiency is high, and it can be applied to scenes where the energy consumption is strictly limited and it is difficult to support lighting multiple groups of light sources for a long time. (6) The site layout flexibility of visible light emitter is high, which can be applied to scenes with small ceiling size or limited positions for candidate installation of multiple groups of light sources. (7) The light source has a high potential to benefit the old, and can be applied to scenes where some light sources are aging or even failing and cannot continue to send out positioning signals normally. (8) It does not rely on the cooperation of multiple light sources, and can be applied to the scene where the light sources are difficult to cooperate and synchronize, and it is difficult to support the effective operation of the traditional multi-lamp positioning algorithm. (9) The user customization is outstanding, which can be applied to the scene where the user has special customization requirements for single lamp positioning.
The visible light combined azimuth beam positioning method cater to single access is
proposed by comprehensively considering the development shackles and commercialization requirements of the visible light positioning technology, and can be applied to diversified practical scenes, especially the application scenes with limited LED light source foundation and even a single light source (which can also be expressed as a single access point), and still provide a reliable, effective and practical visible light positioning technical scheme for the mobile terminal.
The above technical features constitute the embodiments of the present invention, which
have strong adaptability and implementation effect, and can increase or decrease
unnecessary technical features according to actual needs to meet the needs of different
situations.
Claims (6)
1. A visible light combined azimuth beam positioning method cater to single access point,
characterized by comprising the following steps:
Step 1, the positioning controller module in the visible light access point subsystem
periodically constructs a time-division beam activation signal, which carries positioning
data frame structures, each positioning data frame structure comprises frame headers and
loads, wherein the frame header internally contains one synchronization sequence for
synchronizing with the mobile terminal subsystem, and the load internally contains
azimuth beam activation state information associated with each azimuth beam and
omnidirectional beam. Each positioning data frame structure only has an associated
bearing space of the optical beam to be activated, which contains one optical beam
identifier associated with the activated optical beam, and the visible light access point
subsystem sends positioning data frame.
Step 2, loading the frame header of the positioning data frame in the visible light access
point subsystem to all LED light sources of LED lighting facilities providing multi
directional optical beams, wherein the LED lighting facilities providing multi-directional
optical beams are the only visible light sources of application scenes.
Step 3, the visible light access point subsystem loads the internal load of each part of the
positioning data frame to each azimuth LED light source of the LED lighting facility
providing multi-directional optical beams, each LED light source is driven to light up by
the light source driving module of the visible light access point subsystem and loads the
corresponding beam activation state bearing information, and loads its internal load to the light source driving module input terminals of all optical beams continuously and in parallel along with each positioning data frame, and all azimuth beams and omnidirectional beams sequentially send their own optical beam identifications.
Step 4, the mobile terminal subsystem receives the optical beam identification of the
visible light signal.
Step 5, the mobile terminal subsystem measures the load signal intensity of the optical
beam identification and captures the strongest optical beam identification information.
Step 6, the mobile terminal subsystem searches the optical beam spatial association sector
list to obtain the basic spatial orientation information of the optical beam spatial sector
where the mobile terminal is located.
Step 7, the omnidirectional high-power LED light source or LED light source sub-array
in the normal direction of the LED lighting facility sends out an omnidirectional visible
light positioning auxiliary signal, and the mobile terminal subsystem captures the
omnidirectional positioning auxiliary light signal and measures the signal intensity.
Step 8, according to the measured signal intensity, the radial distance between the LED
lighting facility and the mobile terminal is obtained.
Step 9, the mobile terminal subsystem determines the basic spatial position of the mobile
terminal according to the obtained basic spatial orientation information and radial
distance of the mobile terminal.
2. The visible light combined azimuth beam positioning method cater to single access
point according to claim 1, characterized by obtaining the precise spatial position of the
mobile terminal according to the following method: the mobile terminal subsystem
captures the strongest N strongest beam azimuth beam intensity values. Then, the two
dimensional spatial position fingerprint records stored in the fingerprint database and
respectively associated with the N strongest beam azimuth beams are called by the position
fingerprint matching module in the visible light access point subsystem. In the fingerprint
records of N strongest beam, the random iterative optimization search of position fingerprint
matching is carried out near the basic spatial position of the mobile terminal. The visible
light access point subsystem sends the N strongest beam azimuth beams to the mobile
terminal. The mobile terminal subsystem replaces the basic spatial position information
of the mobile terminal with the position information obtained by random iterative
operation of fingerprint matching to obtain the precise spatial position of the mobile
terminal.
3. The visible light combined azimuth beam positioning method cater to single access
point according to claim 1 or 2, characterized in that the random iterative optimization
search comprises: (1) Performing mean square operation on the deviation between the
signal intensity in the fingerprint records of the N strongest beam and the azimuth beam
intensity values of the N strongest beam fed back by the mobile terminal subsystem to obtain
the root mean square errorPMS error - candidate position between them. (2) Performing mean
square operation on the deviation between the signal intensity of the basic spatial position
of the mobile terminal fed back by the mobile terminal subsystem in the fingerprint
records of the N strongest beam and the azimuth beam intensity values of the N strongest beam fed back by the mobile terminal subsystem to obtain the root mean square errorRMSerror current position. (3) IfRMS error - candidate position < RMS error - current position, replace the current position with candidate position. If PMS error - candidate position ;> RMS error - current position, keep the current position without updating and enter the next iteration until the termination condition of stochastic iterative optimization search is reached.
4. The visible light combined azimuth beam positioning method cater to single access
point according to claim 3, characterized in that the termination condition is one of the
following conditions: (1) The number of iterations reaches the preset maximum value.
(2)RMS error - current position is less than the preset deviation threshold. (3) The time
consumption of stochastic iterative optimization search exceeds the preset time
consumption threshold.
5. The visible light combined azimuth beam positioning method cater to single access
point according to claim 1 or 2 or 4, characterized in that the spatial structure of the
optical beam emission lampshade of the LED lighting facility providing multi-directional
optical beams is hemispherical or ellipsoidal or conical at the upper part and cylindrical at
the lower part.
6. The visible light combined azimuth beam positioning method cater to single access
point according to claim 3, characterized in that the spatial structure of the optical beam
emission lampshade of the LED lighting facility providing multi-directional optical
beams is hemispherical or ellipsoidal or conical at the upper part and cylindrical at the
lower part.
FIGURES 1/16
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