TW201721094A - Transmitter array, receiver, and positioning system - Google Patents

Abstract

A positioning system may include a transmitter array including a plurality of visible light positioning units. Each visible light positioning unit may include light-emitting diodes. Each of the light-emitting diodes may be configured to emit a visible light including an identifier portion associating the visible light with the light-emitting diode, and a phase data portion. The positioning system may include a receiver including a detector configured to receive the visible lights emitted by the light-emitting diodes of each of the plurality of visible light positioning units. The receiver may be configured to select one visible light positioning unit of the plurality of visible light positioning units based on the identifier portions of the visible lights, and may be further configured to determine a position of the receiver based on the phase data portions of the visible lights emitted by light-emitting diodes of the selected visible light positioning unit.

Description

Transmitter array, receiver and positioning system

This application is hereby incorporated by reference in its entirety by reference in its entirety in its entirety in the the the the the the the the the the

Some embodiments of the invention are related to transmitter arrays, receivers, and/or positioning systems. Some embodiments of the invention are directed to methods of constructing a positioning system. Some embodiments of the invention are directed to methods of determining the position of a receiver.

There is an urgent need for high accuracy (in centimeters) and low-cost indoor positioning (also known as indoor localization) systems. It is expected that systems with the above features will be considered the most anticipated and popular next generation indoor wireless systems. The above indoor positioning market, predicted by ABI Research, will reach $5 billion in 2018. Consumer applications for indoor location information will have near-infinite potential. Today's indoor positioning applications and services are only at the beginning.

Relevant applications span a wide range of applications, including: (1) Navigation of humans and robots: High-precision positioning systems have the potential to be used in navigation applications in unfamiliar indoor environments. Some examples may include controlling the robot to make the above robot Move along an accurate path; guide passengers at airports or subway stations; and visit visitors who help museums, art galleries, office buildings or shopping malls. (2) Tracking of people or things: In one example, the location of different medical staff or equipment in a hospital can be tracked to improve operational efficiency and effectiveness. Other possible applications may include tracking items in a warehouse, or some assets in an organization. (3) Industrial applications: Such applications may include navigation of indoor cars, precise operation of automated production processes, and the like.

As technology continues to improve and has better and more accurate positioning information, new and more desirable applications can be developed to serve and entertain the mass consumer market.

However, today's indoor positioning systems are unable to achieve high-order positioning accuracy (PA) and low cost requirements. The Global Positioning System (GPS) has been widely used since 1995 and is now used worldwide (always in new and unexpected ways). However, GPS satellites have no direct visibility into the interior of the building, causing GPS receivers (Rxs) to generally not function well in indoor or basement spaces.

Even though GPS positioning can be used, for many indoor applications, there is not enough accuracy (on the order of centimeters). The accuracy of GPS for the above situation is quite low, generally in the order of meters. Today's indoor positioning technology (such as infrared (IR)), ultrasonic (ultrasound), radio-frequency identification (RFID), wireless local area network (WLAN) (also known as WiFi), Bluetooth, sensor networks, and ultra-wideband (UWB) have been developed. However, the above system has Low accuracy and/or high development costs on the other hand.

Some embodiments of the present invention provide a positioning system. The positioning system can include an array of transmitters including a plurality of visible light positioning (VLP) units. Each of the above visible light positioning units includes a plurality of light-emitting diodes (LEDs). Each of the light emitting diodes is configured to transmit a visible light, the visible light comprising an identification portion that causes the visible light to be associated with the light emitting diode, and a phase data portion. The positioning system can include a receiver, which can include a detector. The detector is configured to receive the visible light transmitted by the light emitting diodes of each of the visible light positioning units. The receiver can be configured to select one of the visible light positioning units of the visible light positioning units based on the identification portions of the visible light. The receiver is further configurable to determine a position of the receiver based on the phase data portions of the visible light transmitted by the light emitting diodes of the selected one of the visible light positioning units.

Some embodiments of the invention provide a transmitter array. The transmitter array can include a plurality of visible light positioning units. Each of the above visible light positioning units may include a plurality of light emitting diodes. Each of the above-described light emitting diodes can be configured to transmit a visible light comprising an identification portion that causes the visible light to be associated with the light emitting diode, and a phase data portion. The visible light transmitted by the light emitting diodes of each of the visible light positioning units can be configured to be received by one of the receivers. The identification portions of the visible light can be configured to be used by the receiver to select one of the visible light positioning units. One of the selected visible light positioning units The portion of the phase data of the visible light transmitted by the illuminating diode can be configured to be used by the receiver to determine a position of the receiver.

Some embodiments of the present invention provide a receiver. The receiver can include a detector configured to receive a plurality of visible light transmitted by a plurality of light emitting diodes of each of the visible light positioning units of the plurality of visible light positioning units. Each of the above visible lights includes an identification portion that causes the visible light to be associated with the light emitting diode, and a phase data portion. The receiver can be configured to select one of the visible light positioning units of the visible light positioning units based on the identification portions of the visible light. The receiver is further configurable to determine a position of the receiver based on the phase data portions of the visible light transmitted by the light emitting diodes of the selected one of the visible light positioning units.

Some embodiments of the invention provide a method of constructing a positioning system. The method includes providing a transmitter array, the transmitter array including a plurality of visible light positioning units, each of the visible light positioning units including a plurality of light emitting diodes. Each of the light emitting diodes is configured to transmit a visible light, the visible light comprising an identification portion that causes the visible light to be associated with the light emitting diode, and a phase data portion. The method also includes providing a receiver, the receiver including a detector. The detector can be configured to receive the visible light transmitted by the light emitting diodes of each of the visible light positioning units. The receiver can be configured to select one of the visible light positioning units of the visible light positioning units based on the identification portions of the visible light. The receiver is further configurable to determine a position of the receiver based on the phase data portions of the visible light transmitted by the light emitting diodes of the selected one of the visible light positioning units.

Some embodiments of the present invention provide for determining a location of a receiver method. The method includes receiving, by one of the receivers, a plurality of visible light transmitted by a plurality of light-emitting diodes of each visible light positioning unit of the plurality of visible light positioning units, wherein each of the visible light is transmitted through a light-emitting diode. And the visible light includes an identification portion that causes the visible light to be associated with the light emitting diode, and a phase data portion. The method can include selecting, by the receiver, one of the visible light positioning units based on the identification portions of the visible light. The method also includes determining, by the receiver, the location of the receiver based on the phase data portions of the visible light transmitted by the light emitting diodes of the selected one of the visible light positioning units.

100‧‧‧ Positioning System

102‧‧‧Transmitter array

104a, 104b‧‧‧ visible light positioning unit

106a-106d‧‧‧Lighting diode

108‧‧‧ Receiver

110‧‧‧Detector

202‧‧‧Transmitter array

204a, 204b‧‧‧ visible light positioning unit

206a-206d‧‧‧Lighting diode

208‧‧‧ Receiver

210‧‧‧Detector

300a‧‧‧ Schematic

302, 304‧‧‧ steps

300b‧‧‧ Schematic

312-316‧‧‧Steps

400‧‧‧ Positioning System

402‧‧‧Transmitter array

404a-404h‧‧‧ Visible Positioning Unit

406‧‧‧Lighting diode

408a-408d‧‧‧ Receiver

‧‧‧irradiance angle

θ ‧‧‧ incident angle

Field of view of φ _c ‧‧‧ receiver

d _i ‧‧‧distance

x, y, z ‧ ‧ dimensions

d _int ‧‧‧distance

Rx( U _x , U _y , U _z )‧‧‧ Receiver position

500a‧‧‧ data frame

502‧‧‧ Identification information

504‧‧‧Continuous sine wave

500b‧‧‧ Schematic

f _i , f ₁ - f ₅ ‧‧‧ frequency

c ‧‧‧Light speed

Φ _i ‧‧‧ phase

the initial phase φ ₀ ‧‧‧

600‧‧‧ Flowchart

602-608‧‧‧Steps

‧‧‧ cycle number N _ave

CDF‧‧‧ cumulative distribution function

RMSE‧‧‧ root mean square error

The invention may be better understood by reference to the detailed description of the specification, which is considered in the <RTIgt; The drawings of the present invention are as follows: Figure 1 is a schematic illustration of a positioning system in accordance with some embodiments of the present invention.

Figure 2A is a schematic illustration of a transmitter array in accordance with some embodiments of the present invention.

Figure 2B is a schematic illustration of a receiver in accordance with some embodiments of the present invention.

3A is a schematic illustration of a method of constructing a positioning system in accordance with some embodiments of the present invention.

Figure 3B is a schematic illustration of a method of determining the position of a receiver in accordance with some embodiments of the present invention.

Figure 4 is a schematic illustration of a positioning system in accordance with some embodiments of the present invention.

Figure 5A is a schematic illustration of a data frame of a modulated signal in accordance with some embodiments of the present invention.

Figure 5B is a schematic illustration of five consecutive sinusoidal signals in accordance with some embodiments of the present invention.

Figure 6 is a flow diagram of a location estimation procedure at a receiver (Rx) in accordance with some embodiments of the present invention.

Figure 7 is a graph showing the cumulative distribution function of the estimated error of the i-th visible light locating unit in a space C _i (2.5 x 2.5 x ³ m ³ ) and the root mean square error of a receiver position, in accordance with some embodiments of the present invention. Figure.

The detailed description is set forth with reference to the claims, Each of the embodiments herein is described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized, and structural and logical changes may be employed without departing from the scope of the invention. The various embodiments are not necessarily mutually exclusive, and some embodiments may be combined with other one or more embodiments to form a new embodiment.

The various embodiments described in one of the various methods or apparatus of the present specification can be similarly effective to other methods or apparatus. Similarly, the various embodiments described in one of the methods of the present specification can be similarly effective for a device and vice versa.

Features described in one embodiment of the present specification may be applied to the same or similar features of other embodiments. The features described in one embodiment of the present specification may be applied to other embodiments as appropriate, even if not explicitly described in the other embodiments above. Furthermore, the addition and/or combination and/or replacement of one of the features described in one embodiment of the present specification may be applied to other realities accordingly. The same or similar features of the embodiment.

In the various embodiments of the present specification, the words "a" and "the" are used to describe one or more features or elements.

In various embodiments of the present specification, the terms used to describe a numerical value: "about" or "approximate", includes the precise value and the reasonable difference.

The term "and/or" as used in this specification includes any and all combinations of one or more of the associated listed items.

Some embodiments of the present invention provide a positioning system. 1 is a schematic illustration of a positioning system 100 in accordance with some embodiments of the present invention.

The positioning system 100 can include a transmitter array 102 that includes a plurality of visible light positioning units (e.g., visible light positioning units 104a, 104b). Each of the visible light positioning units (eg, visible light positioning units 104a, 104b) may include a plurality of light emitting diodes (eg, visible light positioning unit 104a includes light emitting diodes 106a, 106b; visible light positioning unit 104b includes light emitting diodes 106c, 106d). Each of the light emitting diodes (e.g., light emitting diodes 106a-106d) can be configured to transmit a visible light comprising an identification portion that causes the visible light to be associated with the light emitting diode, and a phase data portion. The positioning system 100 can include a receiver 108 that includes a detector 110. The detector 110 can be configured to receive the visible light transmitted by the light emitting diodes (eg, the light emitting diodes 106a-106d) of each of the visible light positioning units (eg, visible light positioning units 104a, 104b). The receiver 108 can be configured to select one of the visible light positioning units (eg, the visible light positioning units 104a, 104b) based on the identification portions of the visible light (eg, visible light positioning units) Element 104a). The receiver 108 is further configurable to determine the phase data of the visible light transmitted by the light emitting diodes (eg, the light emitting diodes 106a, 106b) of the selected visible light positioning unit (eg, the visible light positioning unit 104a). In part, the position of one of the receivers 108 is determined.

In other words, the positioning system 100 can include an array 102 of light emitting diodes (e.g., light emitting diodes 106a-106d) and can be divided into a plurality of visible light positioning units 104a, 104b. Each of the light-emitting diodes (eg, light-emitting diodes 106a-106d) can transmit a visible light, and the visible light can include an identification portion (the identification portion encodes information about a source of light-emitting diodes for transmitting the specific visible light) and A phase data section. The positioning system 100 can also include a receiver 108 (and the receiver 108 includes a detector 110) that receives the visible light from the light emitting diodes (eg, the light emitting diodes 106a-106d) and selects a visible light positioning unit to Perform further processing. The phase data portions of the visible light transmitted by the selected light-emitting diodes (eg, the light-emitting diodes 106a, 106b) of the selected visible light positioning unit (eg, the visible light positioning unit 104a) can be applied to the determination receiver 108 location.

Some embodiments of the invention may be used to alleviate or solve one or more problems or items that are subject to the subject matter. Some embodiments of the present invention may have lower complexity. For example, the receiver 108 may only rely on the light-emitting diodes of the selected visible light positioning unit (eg, the visible light positioning unit 104a) (eg, the light-emitting diodes 106a, 106b). The information provided is used to determine the location of the receiver 108 without relying on the LEDs 106a-106d of the overall transmitter array 102. Some embodiments of the present invention can provide better precision than conventional systems by detecting visible light from a plurality of light-emitting diodes, for example, ultra-wideband (ultra-wideband) (UWB)), ultrasonic (infrared (IR)) based system. Some embodiments of the present invention may use a light-emitting diode that has been applied to provide indoor illumination, and thus may reduce cost. Some embodiments of the present invention may not generate electromagnetic interference (EMI), which is different from a conventional radio frequency (RF) based positioning system. Some embodiments of the present invention may provide a secure and privacy positioning system (based on optical radiation that does not penetrate walls or opaque objects).

1 is a generalized illustration of a positioning system 100 in accordance with some embodiments of the present invention, and should not impose any limitation on the present invention. For example, the number of visible light positioning units described above need not be limited to two, and may include more than two numbers. For example, the number of visible light positioning units may be two, three, four or more. In addition, the number of light-emitting diodes in each visible light positioning unit need not be limited to two, and may include two or more numbers.

Each visible light can be transmitted by a light emitting diode, and the identification portion of a particular visible light can identify or provide information about the light emitting diode that transmits the particular visible light. The phase data portion may include or may be a repeated signal (eg, a sinusoidal signal). When the visible light propagates and passes through different distances, the signals of the phase data portion may be in different phases corresponding to the different distances. Therefore, the phase data portion can provide information on the above-mentioned visible light propagation distance.

In some embodiments, each visible light location unit (eg, visible light location unit 104a, 104b) can include four or five light emitting diodes.

In some embodiments, the receiver 108 can be the detector 110. The detector 110 can be or can include a photodiode.

In some embodiments, the phase data portions of the visible light transmitted by different light emitting diodes (eg, light emitting diodes 106a, 106b) of each visible light positioning unit (eg, visible light positioning unit 104a) may be The modulation is made to have substantially the same initial phase and to have substantially different (modulated) frequencies. In other words, different light-emitting diodes (e.g., light-emitting diodes 106a, 106b) within a visible light locating unit can be synchronized, thus leaving a first light-emitting diode (e.g., light-emitting diode 106a). The visible light and the visible light leaving a second light emitting diode (e.g., light emitting diode 106b) may be in the same phase. However, the visible light leaving a first light-emitting diode (for example, the light-emitting diode 106a) and the visible light leaving a second light-emitting diode (for example, the light-emitting diode 106b) may have different (modulated) frequencies. . Local synchronization (i.e., local synchronization) of the complex LEDs within the same visible light location unit can reduce synchronization complexity and eliminate the need for the receiver 108 to include a local oscillator to measure different phase offsets.

In some embodiments, the phase data portions of the visible light received by the different light-emitting diodes of the selected visible light positioning unit and received by the detector 110 may have different phase offsets (for For each other). In other words, the phase data portion of one of the visible light transmitted by the first light-emitting diode of one of the selected visible light positioning units may have a first phase shift, and one of the selected visible light positioning units is the second light-emitting diode. The phase data portion of one of the visible light transmitted by the polar body may have a second phase offset different from the first phase offset. The difference in phase offset described above may be derived from substantially the same initial phase as described above and substantially different frequencies as described above. When different light-emitting diodes of the same visible light positioning unit (for example, visible light positioning unit 104a) are emitted The visible light is transmitted from the light-emitting diodes (eg, the light-emitting diodes 106a, 106b) to different distances to reach the detector 110, and the visible light may be based on one of the same initial phase and different frequencies. And with different phase offsets.

In some embodiments, the identification portion of the visible light and the phase data portion transmitted by each of the light-emitting diodes can be modulated to substantially the same frequency. The visible portion of a visible light can be modulated to the same frequency as the phase data portion of the visible light. The identification portion of the visible light transmitted by each of the light-emitting diodes and the phase data portion can be modulated to a radio frequency. The identification portion of the visible light transmitted by each of the light-emitting diodes can be modulated by one of the binary phase shift keying (BPSK) identification data. The above identification data is unique to each of the light-emitting diodes (and may have a position regarding the individual light-emitting diodes). Adjusting the identification portion of a visible light to the same frequency as the phase data portion of the visible light, whereby the identification portion and the phase data portion are compared with the identification portion of another light-emitting diode in the same visible light positioning unit The phase data portion has different frequencies, thereby allowing complex signals/visible light originating from different light-emitting diodes within the same visible light locating unit to be more easily differentiated or independent of each other.

In some embodiments, the receiver 108 can be configured to ignore or reject the plurality of light emitting diodes (eg, light emitting diodes 106c, 106d) that are not selected by the plurality of visible light positioning units (eg, visible light positioning unit 104b). The complex phase data portion of the complex visible light. The receiver 108 can be configured to process only the plurality of light emitting diodes (eg, the light emitting diodes 106a, 106b) of the selected visible light positioning unit (eg, the visible light positioning unit 104a) to be visible Light, by which the position of the receiver 108 is determined. The visible light transmitted by the light-emitting diodes (e.g., light-emitting diodes 106c, 106d) of the visible light positioning unit (e.g., visible light positioning unit 104b) that is not selected may not be processed. The complexity can be reduced by processing only the visible light transmitted by the light-emitting diodes (e.g., light-emitting diodes 106a, 106b) of the selected visible light positioning unit (e.g., visible light positioning unit 104a).

The receiver 108 can be configured to capture signals originating from any valid adjacent visible light location units (eg, visible light location units 104a, 104b), thereby selecting the highest signal in the visible light location units (eg, visible light location units 104a, 104b) a visible light locating unit (eg, visible light locating unit 104a) of a plurality of light-emitting diodes of a signal-to-noise ratio (SNR), whereby the first determination and selection of the receiver 108 are in the plurality of regions An area. Each zone can be associated with a visible light location unit. The receiver 108 is further configurable to process a complex phase data portion of the complex visible light transmitted by the plurality of light emitting diodes of the visible light positioning unit of the selected region, thereby identifying or determining that the receiver 108 is in the selected region The exact location.

In some embodiments, the selected visible light positioning unit (eg, visible light positioning unit 104a) may include a plurality of light emitting diodes (eg, light emitting diodes 106a, 106b) having signal to noise ratios , a plurality of light emitting diodes (eg, light emitting diodes 106c, 106d) that are higher than the selected visible light positioning unit (eg, visible light positioning unit 104b). In other words, a visible light positioning unit (e.g., visible light positioning unit 104a) having a plurality of light emitting diodes having the highest signal noise ratio can be selected. The receiver 108 can be configured to determine the plurality of light emitting diodes of each of the visible light positioning units based on the identification portion of the visible light Signal noise ratio. In some embodiments, the receiver 108 can be configured to determine an average signal to noise ratio of the plurality of light emitting diodes of each of the visible light positioning units (eg, visible light positioning units 104a, 104b). The receiver 108 can be further configured to compare the complex average signal to noise ratios of the plurality of light-emitting diodes of the different visible light positioning units (eg, the visible light positioning units 104a, 104b), such as the visible light positioning unit 104a. 104b) Selecting a visible light positioning unit (eg, visible light positioning unit 104a). The selected visible light positioning unit (for example, the visible light positioning unit 104a) may include a plurality of light emitting diodes, and the average signal noise ratio of the light emitting diodes is higher than the selected visible light positioning unit (for example, the visible light positioning unit 104b). The plurality of light-emitting diodes.

The receiver 108 may further determine the visible light positioning units (eg, before selecting a visible light positioning unit (eg, the visible light positioning unit 104a) from the visible light positioning units (eg, the visible light positioning units 104a, 104b) based on the signal noise ratio. The signal to noise ratios of the light-emitting diodes (e.g., light-emitting diodes 106a-106d) of the visible light positioning units 104a, 104b).

If the signal to noise ratio of the selected visible light positioning unit is at or above a predetermined threshold, the receiver 108 can process to determine the position of the receiver 108. The signal noise ratio of the selected visible light positioning unit (for example, the visible light positioning unit 104a) may be all the light emitting diodes (for example, the light emitting diode 106a) in the selected visible light positioning unit (for example, the visible light positioning unit 104a). 106b) One of the average signal to noise ratios. On the other hand, the signal noise ratio of the selected visible light positioning unit (for example, the visible light positioning unit 104a) may be all the light emitting diodes (for example, the light emitting diode) in the selected visible light positioning unit (for example, the visible light positioning unit 104a). The lowest signal of one of the pole bodies 106a, 106b) Noise ratio. In other words, the light-emitting diodes (e.g., light-emitting diodes 106a, 106b) of the selected visible light positioning unit (e.g., visible light positioning unit 104a) may be required to conform to the position of the receiver 108 before being determined. A condition for a predetermined signal noise ratio threshold.

If the signal noise ratio of the selected visible light positioning unit (eg, visible light positioning unit 104a) is lower than the predetermined signal noise ratio threshold, the receiver 108 may repeat the selection procedure after a predetermined time. In other words, if the signal noise ratio of the selected visible light positioning unit (eg, visible light positioning unit 104a) is lower than the predetermined signal noise ratio threshold, the receiver 108 can be configured to re-determine the visible light positioning units. Waiting for a predetermined time before the signal noise ratio of the light-emitting diodes (e.g., light-emitting diodes 106a-106d) (e.g., visible light positioning units 104a, 104b). The receiver 108 may re-determine the visible light positioning units (eg, visible light positioning) before selecting a visible light positioning unit (eg, the visible light positioning unit 104a) from the visible light positioning units (eg, the visible light positioning units 104a, 104b) based on the signal noise ratio. The signal to noise ratio of the light emitting diodes (e.g., light emitting diodes 106a to 106d) of the cells 104a, 104b).

Receiver 108 can be configured to determine the signal to noise ratio prior to determining the location of receiver 108.

In some embodiments, the receiver 108 can be configured to determine the position of the receiver through a differential phase shift measurement and/or a trilateration algorithm.

a phase portion of a plurality of visible light transmitted by a plurality of light-emitting diodes of a first visible light positioning unit, and a second visible light positioning unit The phase data portion of the plurality of visible light transmitted by the plurality of light-emitting diodes may have substantially different initial phases. In other words, the plurality of light-emitting diodes of different visible light positioning units can be unsynchronized.

In some embodiments, the light emitting diodes can be white light emitting diodes or diodes configured to emit white light. In some embodiments, the light emitting diodes can be blue light emitting diodes coated with a yellow phosphorescent coating (ie, diodes configured to emit blue light). When the blue light emitting diodes are coated with a yellow phosphorescent coating, the light emitting diodes can be configured to emit white light.

In some embodiments, the receiver 108 may further include a demodulator (eg, an in-phase and quadrature (I/Q) based demodulator based on differential phase shift measurements, the demodulator being The configuration is configured to determine the location of the receiver 108. The demodulator can be configured to determine a difference in phase shift received by the detector 110. The demodulator can be configured to determine the detector 110 a difference in the in-phase offset between the visible light transmitted by the first light-emitting diode and the visible light emitted by the second light-emitting diode, the first light-emitting diode and the second light-emitting diode The same visible light positioning unit belongs to the same. The demodulator can be electrically connected to the detector 110.

In some embodiments, the receiver 108 can further include a processor or processing circuitry. The processor or the processing circuit can be configured to determine the location of the receiver 108 based on the plurality of visible light received by the detector 110 (and transmitted by the selected visible light positioning unit (eg, visible light positioning unit 104a) (eg, Through differential phase shift measurement and / or trilateration algorithm). The processor or the processor circuit can be configured to determine a signal to noise ratio of the plurality of light emitting diodes of each of the visible light positioning units. The processor or processor circuit can be configured to select a plurality A visible light positioning unit of the plurality of light emitting diodes having the highest signal noise ratio in the visible light positioning unit. The processor or the processor circuit can be electrically connected to the detector and/or the demodulator.

In some embodiments, the receiver 108 can further include a filter of the detector 110. The filter can be configured to allow blue light to pass through and reach the detector 110m, and can block or filter out other components of the visible light originating from the plurality of light emitting diodes 106.

In some embodiments, the receiver 108 can include a post-equalization circuit arrangement configured to be electrically coupled to the detector 110. The equalizer circuit configuration can be configured to relax the modulation width requirements of the light emitting diodes (actually equivalent to increasing the modulation width of the light emitting diodes).

In some embodiments, the positioning system 100 can achieve a positioning accuracy of less than about 100 centimeters, less than about 20 centimeters, less than about 10 centimeters, less than about 7 centimeters, or less than about 5 centimeters. The receiver 108 can be configured to determine the position of the receiver 108 with a positioning accuracy of less than about 100 centimeters, less than about 20 centimeters, less than about 10 centimeters, less than about 7 centimeters, or less than about 5 centimeters.

Some embodiments of the invention may provide a transmitter array. 2A is a schematic diagram of a transmitter array 202 in accordance with some embodiments of the present invention.

Transmitter array 202 can include a plurality of visible light location units (e.g., visible light location units 204a, 204b). Each of the visible light positioning units (eg, visible light positioning units 204a, 204b) may include a plurality of light emitting diodes (eg, light emitting diodes 206a-206d). Each of the light emitting diodes (eg, light emitting diodes 206a-206d) can be configured to transmit a visible light that includes causing the See an identification portion of the light associated with the light emitting diode, and a phase data portion. The plurality of visible light transmitted by the plurality of light-emitting diodes (eg, light-emitting diodes 206a-206d) of each of the visible light positioning units (eg, visible light positioning units 204a, 204b) can be configured to be received by one of the receivers of the receiver . The identification portions of the visible light can be configured for use by the receiver to select one of the visible light location units (eg, visible light location units 204a, 204b) (eg, visible light location unit 204a). The phase data portions of the visible light transmitted by the selected light-emitting diodes (eg, light-emitting diodes 206a, 206b) of the selected visible light positioning unit (eg, visible light positioning unit 204a) may be configured for the receiver Used to determine the location of one of the receivers.

2A is a general illustration of a transmitter array 202 in accordance with some embodiments of the present invention and should not impose any limitation on the present invention. For example, the number of visible light positioning units described above need not be limited to two, and may include more than two numbers. For example, the number of visible light positioning units may be two, three, four or more. In addition, the number of light-emitting diodes in each visible light positioning unit need not be limited to two, and may include two or more numbers.

Some embodiments of the present invention provide a receiver. Figure 2B is a schematic illustration of a receiver 208 in accordance with some embodiments of the present invention.

The receiver 208 can include a detector 210 that can be configured to receive the plurality of visible light transmitted by the plurality of light emitting diodes of each of the visible light positioning units. Each visible light may include an identification portion that causes the visible light to be associated with a light emitting diode, and a phase data portion.

Receiver 208 can be an optical receiver. receive The 208 can be configured to select one of the visible light locating units of the visible light locating units based on the identification portions of the visible light. The receiver 208 can be configured to determine a complex signal to noise ratio of the light emitting diodes of each of the visible light positioning units based on the identification portions of the visible light.

The selected visible light positioning unit may comprise a plurality of light emitting diodes, wherein the light emitting diodes have a higher signal to noise ratio than the plurality of light emitting diodes of the selected visible light positioning unit. The receiver 208 is further configurable to determine a position of the receiver 208 based on a plurality of complex phase data portions of the plurality of visible light transmitted by the light emitting diodes of the selected visible light positioning unit.

FIG. 2B is a general illustration of a receiver 208 provided in accordance with some embodiments of the present invention and should not impose any limitation on the present invention.

Some embodiments of the invention provide a method of constructing a positioning system. 3A is a schematic diagram 300a of a method of constructing a positioning system in accordance with some embodiments of the present invention. The method includes, in step 302, providing a transmitter array, the transmitter array including a plurality of visible light positioning units, each of the visible light positioning units including a plurality of light emitting diodes. Each of the light emitting diodes is configured to transmit a visible light, the visible light comprising an identification portion that causes the visible light to be associated with the light emitting diode, and a phase data portion. The method can also include, in step 304, providing a receiver, the receiver including a detector. The detector can be configured to receive the visible light transmitted by the light emitting diodes of each of the visible light positioning units. The receiver can be configured to select one of the visible light positioning units of the visible light positioning units based on the identification portions of the visible light. The receiver is further configurable to determine the phase data of the visible light transmitted by the light emitting diodes of the selected visible light positioning unit In part, the position of one of the receivers is determined.

In other words, a method of constructing a positioning system can include providing a transmitter array that includes a plurality of light emitting diode groups of a plurality of visible light positioning units. Each of the visible light positioning units may include a number of light emitting diodes. The method can also include providing a receiver, the receiver including a detector. The detector receives the plurality of visible light transmitted by the light emitting diodes. After receiving the visible light, the receiver can determine which particular visible light positioning unit to process further. The receiver performs the above determination by processing the identification portions of the visible light transmitted by the light emitting diodes. Each visible light can be transmitted by a light emitting diode, and a specific visible portion of the visible light can identify or provide information about transmitting one of the specific visible light emitting diodes. After the above determination, the receiver can further determine the position of itself based on the phase data portion of the visible light transmitted by the plurality of light-emitting diodes of the specific visible light positioning unit.

In some embodiments, the complex phase data portions of the complex visible light transmitted by the different light emitting diodes of each of the visible light positioning units can be modulated to have substantially the same initial phase and have substantially different frequencies.

In some embodiments, the complex phase data portions of the plurality of visible light transmitted by the different light-emitting diodes of the selected visible light positioning unit and received by the detector may have different phase offsets.

In some embodiments, the identification portion of the visible light and the phase data portion transmitted by each of the light-emitting diodes can be modulated to substantially the same frequency. The identification portion of the visible light transmitted by each of the light-emitting diodes can be used One of the binary phase shift keying (BPSK) identifies the data to be modulated.

The receiver can be configured to ignore or reject the complex phase data portion of the complex visible light transmitted by the plurality of light-emitting diodes of the plurality of visible light positioning units that are not selected.

The receiver may be configured to determine a complex signal to noise ratio of the plurality of LEDs of each of the visible light positioning units based on the identification portions of the visible light. The receiver is further configured to determine the signal to noise ratios of the LEDs of the visible light positioning units before selecting a visible light positioning unit from the visible light positioning units. The receiver can be configured to select a visible light positioning unit from the visible light positioning units based on the signal noise ratios. The signal-to-noise ratio of the plurality of light-emitting diodes of the selected visible light positioning unit may be higher than the signal-to-noise ratio of the plurality of light-emitting diodes of the selected visible light positioning unit. The receiver is further configurable to determine the signal to noise ratio prior to determining the location of the receiver.

The position of the receiver can be determined by differential phase shift measurement and trilateration algorithm.

The plurality of visible light transmitted by the plurality of light-emitting diodes of the different visible light positioning units may be asynchronous. The phase data portion of the plurality of visible light transmitted by the plurality of light-emitting diodes of the first visible light positioning unit and the phase data portion of the plurality of visible light signals transmitted by the plurality of light-emitting diodes of the second visible light positioning unit may be substantially different. Initial phase.

Some current studies have validated the feasibility of different applications of visible light positioning units. In Microsoft Indoor Localization In Competition-IPSN 2014, approximately 20 different low-cost indoor positioning systems were reported. However, among these real-time or near-instant positioning systems, there is still no system that can achieve not only low cost but also the accuracy of the public rating. Cost, complexity, accuracy, coverage and/or stability are the main research challenges of today's indoor positioning systems.

To overcome the above challenges and to meet the requirements of current indoor positioning systems, embodiments of the present invention may provide a low cost, indoor public grading positioning system that provides high accuracy positioning without the need for complex and expensive infrastructure. . In some embodiments, a white illuminated light emitting diode can be included. The white illuminated LED can be additionally used as a positioning tool to provide a more complete solution for the positioning resolution of the public grade. The system in some embodiments may include modulating each of the light-emitting diodes through their own identification information with a continuous sine wave signal of a predetermined frequency and periodically transmitting the signals. Each of the four or five light emitting diodes can be grouped into a single visible light positioning unit, and each four or five light emitting diodes can be locally synchronized in phase. The number of light-emitting diodes that are grouped into a visible light locating unit can vary or vary in different embodiments. A visible light positioning unit receiver Rx can detect signals originating from any one of the visible light positioning units, thereby determining the position of itself by analyzing and processing the received signals and using a predetermined indoor map.

Some embodiments of the invention provide a method of determining the position of a receiver. Figure 3B is a schematic diagram 300b of a method of determining the position of a receiver in accordance with some embodiments of the present invention. The method may include, in step 312, receiving, by each of the receivers, a plurality of visible light transmitted by a plurality of light-emitting diodes of each visible light positioning unit of the plurality of visible light positioning units, wherein each of the channels The visible light is transmitted through a light emitting diode, and the visible light includes an identifying portion that causes the visible light to be associated with the light emitting diode, and a phase data portion. The method includes, in step 314, transmitting, by the receiver, one of the visible light positioning units based on the identification portions of the visible light. The method may further include: in step 316, determining, by the receiver, the location of the receiver based on the phase data portions of the visible light transmitted by the LEDs of the selected visible light positioning unit .

In other words, the detector can detect the complex visible light transmitted by the plurality of LEDs of the different visible light positioning units through a detector of the receiver, and the position of the receiver can be determined. Each visible light can come from a light emitting diode. The visible light can include an identification portion and a phase data portion. The receiver may select a visible light positioning unit from the plurality of visible light positioning units based on the identification portion. The receiver can further determine its position based on the phase data portion of the plurality of visible light transmitted by the plurality of light-emitting diodes of the selected visible light positioning unit.

The method can include: determining, by the receiver, a signal to noise ratio of the light emitting diodes of each of the visible light positioning units based on the portions of the identification data of the visible light. In some embodiments, the selected visible light positioning unit may include a plurality of light emitting diodes having a higher signal to noise ratio than the plurality of light emitting diodes of the selected visible light positioning unit.

In some embodiments, the receiver can be fixed or connected to an item (eg, a robot, a device, etc.). In some embodiments, the receiver can be held or connected to a human or an animal. So the object, the human or The location of the animal can be determined.

Figure 4 is a schematic illustration of a positioning system 400 in accordance with some embodiments of the present invention. The positioning system 400 can be an indoor visible light positioning system. The positioning system 400 can use a white light emitting diode 406. In order to avoid clutter and to improve the sharpness of Figure 4, not every LED 406 is labeled. The light emitting diode 406 can be mounted to the ceiling of an indoor environment to provide illumination.

As shown in FIG. 4, the light emitting diode 406 can be divided into a plurality of visible light positioning units 404a to 404h (which can also be regarded as positioning units). Each of the visible light positioning units 404a-404h may include five light emitting diodes (shown in solid rectangles in each of the visible light positioning units 404a-404h). In some embodiments, each of the visible light positioning units 404a-404h can include four light emitting diodes. The visible light transmitted by each of the light-emitting diodes of a visible light positioning unit can be modulated, so that the modulated visible light includes a unique identification portion (which can be regarded as a light-emitting diode position identification (ID), and Each of the light-emitting diodes is unique and a phase data portion, such as a continuous sine wave of a predetermined frequency fi. The visible light positioning units 404a-404h may form a transmitter (Tx) array 402.

An example of the data ffame of the modulated visible light is shown in FIG. 5A. Figure 5A is a schematic illustration of a data frame 500a of a modulated signal in accordance with some embodiments of the present invention. The data frame 500a can include light-emitting diode position identification information 502 with a continuous sine wave 504.

The modulated signal of each of the light-emitting diodes 406 can be periodically transmitted. In order to facilitate the independent or distinguishing different signals sent by the five LEDs 406 of a visible light positioning unit (404a~404h), the position recognition of each LED 406 can be first modulated to an RF signal. , the RF signal and The accompanying sine waves have the same frequency. The above modulation can be adjusted using a binary phase shift keying. In each visible light positioning unit, five consecutive sinusoidal signals of different frequencies may be locally synchronized in phase, that is, the transmitted visible light may have the same initial phase. Figure 5B is a schematic diagram 500b of five consecutive sinusoidal signals in accordance with some embodiments of the present invention.

It should be noted that the light-emitting diodes 406 of the different visible light positioning units 404a-404h may not need to be fully synchronized, thereby significantly simplifying the problem of synchronization. The visible light positioning unit receivers (Rx) 408a-408d can detect the above signals (that is, the modulated visible light from the light emitting diodes 406 of any one of the visible light positioning units 404a to 404h), and can reject or ignore the other signals. The signals of the LEDs 406 of the adjacent visible light positioning units 404a-404h. The location of each receiver can be determined by analyzing and processing the received signals and using a predetermined indoor map. In some embodiments, a set of five light emitting diodes 406 within a visible light positioning unit 404a-404h can be used to estimate the position of the receiver to address the transmitter 402 and each of the receivers 408a-408d. Exact synchronization problem between. The above problem can be solved by using local synchronization on the transmitter 402 side. A receiver 408a-408d can receive five input signals (each signal is associated with a radio frequency f _i ). The distance ( d _i ) between each of the LEDs 406 and the receivers 408a to 408d can be obtained by a differential phase shift measurement, and the positioning of the receivers 408a to 408d can be estimated (for example, a trilateration calculation) law). It should be noted that the phases of the signals on the sides of the receivers 408a-408d are distance dependent. The phase difference value between a transmitted signal and its corresponding received signal can be converted into a corresponding transmission distance. As described below, the initial phase of an input sinusoidal signal (sent by the light-emitting diode 406) can be defined as φ ₀ (ranging from 0 to 2π). After a distance d _i has been transmitted, the phase of the received signal (i.e., the signal received by a receiver 408a-408d) can be increased to φ _i .

The phase ( φ _i ) of the signal received by a receiver 408a-408d can be: φ _i = φ ₀ + Δ φ _i (1) where Δ φ _i is the phase offset of the transmitted sinusoidal signal of frequency f _i . In some embodiments, an in-phase and quadrature (I/Q) demodulator based on differential phase shift measurements can be employed to measure Δ φ _i .

As described above, the plurality of visible light transmitted by the different light-emitting diodes 406 of the same visible light positioning units 404a-404h may have the same initial phase φ ₀ . Since the visible light (sent by the different light-emitting diodes 406 of the same visible light positioning units 404a-404h) propagates through different distances d _i and different frequencies f _i , the visible light can have different phase offsets Δ φ _i , causing the visible lights received by a receiver 408a-408d to have different phases φ _i .

Based on the above method, the initial phase φ _{0 of} an input sinusoidal signal can be cancelled by the final estimation formula. Therefore, the receivers 408a-408d need not be synchronized to the visible light positioning units 404a-404h, and only downlinks are needed to estimate the position of the receivers 408a-408d, thereby significantly reducing the complexity of the system. degree. Local synchronization of each of the visible light positioning units 404a-404h may be required to provide the same initial phase of the different sinusoidal signals of each of the visible light positioning units 404a-404h (instead of all of the visible light positioning units 404a-404h). In some embodiments, the number of light-emitting diodes 406 of each of the visible light positioning units 404a-404h can be five. If the two RF frequencies are modulated to one of the LEDs 406, the number of LEDs 406 of each of the visible light positioning units 404a-404h can be reduced to four.

Figure 6 is a flow diagram 600 of a location estimation procedure at a receiver (Rx) in accordance with some embodiments of the present invention. In state 1 (step 602), the receiver can begin to detect if there is a line-of-sight (LOS) downlink from any of the visible light location units for further positioning operations. In the state 2 (step 604), after receiving a positioning request, the system (ie, the receiver) can start reading the position identification information (identification part) of the plurality of light-emitting diodes received from a visible light positioning unit. And then updating the location information of the LEDs to a predetermined user map. In state 3 (step 606), the receiver can begin to retrieve different phase shift information from each of the light emitting diodes. The receiver is further operable to calculate a signal to noise ratio for each of the light emitting diodes to determine the reliability of the received signal. After confirming that the received signal is reliable (eg, the signal to noise ratio is greater than 13.6 dB), the location of the receiver can be estimated by an algorithm of state 4 (step 608). If the signals are not reliable, the signals will be ignored and a new capture operation can be performed. After state 4 (step 608), a decision operation can determine whether the location operation is re-executed or terminated. The acquisition rate of the above positioning embodiment can be designed accordingly to adapt the decision operation to different applications to support the mobility of the client.

A common strategy for measuring distance in positioning related applications is to calculate the time of flight (TOF) of a signal. However, for an indoor situation, when the signal propagates at the speed of light and the propagation distance is very small (only a few meters), it is difficult and straightforward to measure the time (in nanoseconds (ns)). Low accuracy. In some embodiments, a differential phase shift measurement method can be employed And an averaging technique can be used to achieve a more accurate estimate. In some embodiments of the positioning system, the position of the receiver can be obtained based on the differential phase shift measurement method and the averaging technique.

Define d _i as the distance between the transmitter T _xi and the receiver R _x and define τ _i as the corresponding propagation time: d _i = τ _i c (2) where c is the speed of light.

τ _i can be: Where Δ φ _i is the phase offset of the transmitted sinusoidal signal (frequency f _i ). It should be noted that d _i may have an indistinguishable range of distances based on the frequency f _i (according to the 2π period of the sine). For example, if f _i is 10 MHz, the corresponding undisturbed distance of d _i may range from about 7.5 meters. As shown in Fig. 4, S ^t _i (t) is set to the input sinusoidal signal of the ith LED, which can also be expressed as: S ^t _i ( t )= S sin(2 πf _i t + φ ₀ ) (4) where S and φ ₀ are the amplitude peaks and the initial phase of the input sinusoidal signal, respectively. After being transmitted through an indoor optical wireless (OW) channel, detected and passed through an RF bandpass filter, the received signal S ^r _i (t) can be: S ^r _i ( t ) = RP _T H _i (0) sin(2 πf _i t +Δ φ _i + φ ₀ )+ n _i ( t ) (5) where R is the photoresponder (PD) response rate (responsivity) P _T is the transmitted optical power and n _i (t) is the additive white Gaussian noise (AWGN).

H _i (0) is the DC gain of the above optical wireless channel, which can be expressed as: Where m is the Lambertian order of the transmitter (Tx), It is the irradiance angle and θ is the incident angle of the receiver (Rx). A _R is the detection surface area of the receiver, T _s ( θ ) is the gain of the optical filter, g( θ ) is the optical concentrator (lens) gain, and φ _c is the field of view of the receiver. (field of view (FOV, semi-angle)).

As shown in the equation (5), the received optical signal S ^r _i (t) may include a number of sinusoidal signal periods. In order to improve the signal to noise ratio of the received signal, an effective method is to use an averaging technique. The averaging method can be based on a principle that the same phase shift information is provided for each of the above-mentioned signal periods (although these signal periods may be obscured by the additive white Gaussian noise n _i (t)). When the noise n _i (t) is added, its average approaches zero. It is assumed here that S ^r _i (t) includes a sine wave of N _ave cycles. The noise n _i (t) has an average of zero and has a variation σ ² . The signal received at time t after k cycles is: S ^r _i ( t - kT ) = r _i ( t - kT ) + n _i ( t - kT ) (7) where: r _i ( t - kT _{) = RP T H i (0} ) sin (2 πf i (t - kT) + Δ φ i + φ 0) (8)

After the combination of the sinusoidal signal period of the N _ave, the average signal ( t ) can be:

Since r _i (t) is time invariant, equation (9) can be re-represented as:

this (T) is an estimate r _i (t) values. The expected value of ( t ) is:

Since E{ n _i (t)}=0, we can get:

therefore, ( t ) is an unbiased estimator of r _i (t). The variation of ( t ) is:

Since the additive white Gaussian noise is independent of the received sinusoidal signal, the covariance terms can be zero. Also, at 1 j When N _ave , n _i ( t - kT ) is independent of n _i [ t -( k + j ) T ], therefore:

Since the number of noise variations is constant, Equation (14) can be re-expressed as: Since Var [ r _i (t)] = 0, you can get:

Before averaging, Var [ S ^r _i (t)] = Var [ n _i (t)]. As shown in the equation (16), after averaging, the above-mentioned variation number is reduced by a factor of N _ave , so the signal-to-noise ratio of the received signal is improved by a factor of N _ave .

In order to measure Δ φ _i , an I/Q (In phase and Quadrature) demodulator can be required. Some embodiments of the present invention may require a local oscillator (local oscillator (LO)) to generate a frequency reference signal f _i is one, and with a phase-locked loop (phase locked loop (PLL)) of the decoding circuit is phase offset Δ φ _i . This local oscillator may need to be accurately synchronized to the transmitted sinusoidal signal, which may significantly increase the complexity of the system and affect the accuracy of the measurement (because there are multiple visible light positioning units). In some embodiments, differential phase shift measurements based on a local oscillator can be used to obtain Δ φ _i , which in turn can be used for trilateration algorithms for position estimation. Equation (5) can be re-expressed as: Where K is the attenuation factor of _i, d _i is the distance between the transmitter _(i the Tx) and receiver (Rx). In order to obtain d _i from the equation (17), a differential phase shift measurement method can be used. Multiplying S ^r ₁ (t) by S ^r ₂ (t) yields: Where n ₁₂ (t) is an additive noise. After passing through a low-pass filter and ignoring the above noise, it can be concluded that: Similarly:

Let ω _i - ω _i-1 = Δ ω (i = 2, 3, 4, 5). By multiplying equations (19) and (20):

After filtering the high frequency portion of equation (23) through a low pass filter: Perform a Hilbert transform on Equation (24):

Based on equations (24) and (25), it can be concluded that:

Similarly:

Based on equations (26) and (28), it can be concluded that:

The individual definitions (x _i , y _i , z _i ) and ( U _x , U _y , U _z ) are the locations of the transmitter and receiver. Further d _i can be calculated as:

The position ( U _x , U _y , U _z ) of the receiver can be obtained based on the equations (29) and (30). The root mean square error (RMSE) of the receiver position of the visible light positioning system can be expressed as: among them( , , ) is the estimated position of the lth receiver; , , ) is the actual position; and N is the total number of measurements.

Numerical simulations and results are presented below. As shown in FIG. 4, each of the visible light positioning units 404a to 404h may have five light emitting diodes 406 at the top, and the light emitting diodes may be arranged in a square shape (ie, four light emitting diodes may be respectively respectively It is disposed at four corners of the square, and one light emitting diode can be disposed at the center of the square). The distance between the light-emitting diode of a corner and the central light-emitting diode can be labeled as d _int (refer to Figure 4). The received signal for the frequency f _i may include a complex period of the sinusoidal signal. Assuming that the average of the noise is zero, the signal-to-noise ratio of the received signal can be improved by the averaging technique, as described in the foregoing. The number of periods used for averaging is denoted by N _ave , and C _i represents the area covered by the ith visible light positioning unit. The related settings described in Komine et al. ("Fundamental analysis for visible-light communication system using LED lights", Consumer Electronics, IEEE Transactions on, Vol. 50, pp. 100-107, 2004) will be described below (here As a reference, the positioning error of the i-th visible light locating unit in an area C _i has been simulated and represented. In this simulation, five RF signals of different frequencies are respectively modulated to five light-emitting diodes of a visible light positioning unit. The first frequency f ₁ is set to 20 MHz, and the difference between the adjacent two frequencies is set to 100 KHz. Figure 7 is a cumulative distribution function of the estimated error of the i-th visible light locating unit in a space C _i (2.5 x 2.5 x 3 m ³ (length x width x height) in accordance with some embodiments of the present invention. CDF)), and a plot 700 of the root mean square error of the receiver position. Based on the estimation formulas of equations (29) through (31), Figure 7 depicts the root mean square error for three different cases. The result indicates that the root mean square error is significantly improved as d _int or N _ave increases. The arrangement of the plurality of light-emitting diodes in a visible light positioning unit can have a significant influence on the performance of the positioning error. In some embodiments, an arrangement of a plurality of light emitting diodes in a visible light positioning unit can be included, the arrangement being selected from a group consisting of a square, a rectangle, and a central light emitting diode One shape and one rectangular shape according to one of the central light-emitting diodes.

In order to achieve the accuracy of the public grading, some embodiments may employ some techniques, which are described in detail below.

Post-equalization technique. It is known that the accuracy of a positioning system based on a light-emitting diode has a strong correlation with a photonic device. The optical transmit power and the variable width are two key parameters that limit the positioning accuracy of the system. By using a light-emitting diode with a higher transmission power and a higher modulation width, the accuracy of the visible light positioning system can be significantly improved. However, some embodiments may use a general illumination system having, for example, an illumination level selected from a range of about 300 lx to about 1500 lx. Therefore, strengthening the modulation width of the light-emitting diode can be the main method for achieving the accuracy of the public classification. It is known that with a post-equalization technique, the 3dB bandwidth of a white light-emitting diode can be increased from a few MHz to about 25 MHz or even higher. As is currently known, this technique may not be employed in indoor visible light positioning systems. On the other hand, a pre-equalization technique can also be used to increase the modulation width of the light-emitting diode. However, pre-equalization may require additional components to be mounted on each of the light-emitting diodes. To maximize the complexity and cost of the system, some embodiments may include a post-equalization circuit configuration. The receiver may include a post-equalization circuit configuration to electrically connect to the detector. The equalizer circuit configuration described above can be configured to relax one of the above-described LEDs. The above content is actually equivalent to increasing the modulation width of the above-mentioned light-emitting diode.

Differential phase shift measurement method. Some technical methods for visible light positioning systems have been studied in the near future. Most of the above studies are based on received signal strength indicator (RSSI) measurements. When the distance between the transmitter array (Tx) and the receiver (Rx) increases, the received message The power of the number may be reduced. However, the effects of object blocking and reflection methods, the relationship between distance and RSSI may not be predicted, and this characteristic may significantly limit the positioning accuracy (PA). In addition, the related research also assumes that the optical power transmitted by each of the light-emitting diodes is accurately grasped. Unfortunately, the above situation may not match the reality. The optical power transmitted above may be very difficult to predict. The transmitted optical power may be based on the particular light-emitting diode and the degree of dimming. Therefore, in practice, only a rough estimate of the location can use the RSSI method. The time-of-arrival (TOA) and time-difference-of-arrival (TDOA) methods are more accurate methods to estimate position. However, for indoor visible light positioning systems, there are two main challenges to achieve a public classification accuracy. First of all, it is very difficult to directly measure the extremely accurate arrival time or arrival time difference, because the distance between the transmitter and the receiver may be very small (about 10 meters) (in the case where the signal propagates at the speed of light). Other problems with time measurement may require high precision synchronization between the transmitter and the receiver. Thus, for an economical optical receiver, differential phase shift measurements can be used in some embodiments. For modulating a continuous sine wave to each of the four or five light-emitting diodes of a visible light locating unit, the distance between each of the light-emitting diodes and the receiver is permeable to the measurement Obtained by the phase difference between the transmitted sine wave signal and the received sine wave signal.

Blue filtering. Currently, most devices used for illumination use a blue light-emitting diode coated with a yellow phosphorescent coating to produce white-emitting light. Due to this yellow phosphorescent coating, the modulation width of the light-emitting diode may be substantially limited to about 3 MHz. As mentioned above, the 3dB modulation width of the white LED can significantly affect the positioning accuracy of the visible light positioning system. therefore, Optical blue filtering may be included in the design of the light receiver in some embodiments to filter out the slow-reacting phosphorescent component of the emitted light, leaving a relatively fast, directly modulated blue emission. In some embodiments, the receiver can include a filter of the detector described above. The filter can be configured to allow blue light to pass to the detector. To further increase the above-described modulation width, a combination of blue filter technology and a simple receiver post-equalization circuit can be employed in some embodiments to allow commercial white LEDs to be modulated to 100 MHz signals. Therefore, the positioning accuracy of the system can be improved by about 5 cm.

Some embodiments may be associated with a visible light positioning system based on an indoor white light emitting diode. Some embodiments may be associated with a low cost indoor public grading system.

Existing white illuminated light emitting diodes may be employed in some embodiments and may not rely on complex infrastructure. In addition, the LEDs are used in both lighting and positioning applications to provide a converted green energy solution for indoor positioning systems. Illumination of illumination systems based on white light-emitting diodes is generally limited to between 300 lx and about 1500 lx. This level of illumination provides a good signal-to-noise ratio that can reach 30dB in the positioning system. By using a noise cancelation technique, a public positioning accuracy of less than 10 cm can be achieved in a general indoor lighting environment.

Some embodiments may use optical radiation and line-of-sight (LOS) transmission, which may be mitigated by more than some RF-based positioning systems (eg, WiFi, Bluetooth, RFID, or GSM). The interference introduced by the route and the accuracy can be improved. On the other hand, compared to other public hierarchical positioning systems (such as UWB, Ultrasound and IR-based systems) By using existing light-emitting diode lighting facilities, some embodiments of the present invention can significantly reduce installation costs for a wide range of applications for indoor environments.

A common strategy for measuring distance in a positioning application is to calculate the fill time (TOF) of a signal. However, when the signal propagates at the speed of light and the range is small (in meters), it may not be feasible to directly measure the above-mentioned filling time (if high positioning accuracy is required). In some embodiments, a method can be used or employed that measures the distance by measuring the phase change of the transmitted signal to achieve a publicly graded positioning accuracy. By modulating a continuous sine wave of four or five light-emitting diodes of a visible light positioning unit, the distance between each of the light-emitting diodes and the receiver can be obtained, and further, the space of the receiver Positioning can be estimated. The number of light-emitting diodes constituting a visible light locating unit can be different in different embodiments.

In some embodiments, a local synchronization scheme may be included whereby the complexity of the system may be reduced or reduced. The light-emitting diode bulbs on the ceiling can be grouped into a plurality of basic positioning units (which can be understood as visible light positioning units), and each of the basic positioning units can include four or five light-emitting diode bulbs. Only the light-emitting diode bulbs in a visible light positioning unit can be synchronized, whereby the synchronization complexity can be significantly reduced. In other words, local synchronization of a plurality of light emitting diodes within a visible light locating unit can be employed in some embodiments. In contrast to embodiments in which each visible light locating unit consists of (or includes) three transmitters or light emitting diodes, some embodiments having four or five light emitting diodes may not require a local at the receiver end. The oscillator measures the differential phase offset. In this case, the receiver can extract the differential phase offset information from the active unit of any downlink link to estimate its position, and may not need Synchronization between the transmitter and the receiver is required, which can significantly improve the positioning accuracy of the system.

Some embodiments may not generate electromagnetic interference (EMI) compared to radio frequency based positioning systems and may be ideal applications in areas where radio frequency is restricted or prohibited, such as airports, seaports, hospitals, and hazardous environments (eg, power generation) Factory, mine). A further advantage is that the light radiation does not penetrate walls or opaque objects. Accordingly, some embodiments may be related to a security and privacy location system.

Various indoor positioning systems for indoor positioning estimation have been proposed and studied. They are based on radio frequency (Wi-Fi, Bluetooth, RFID, GSM and UWB), Ultrasound, Infrared (IR) and Visible light technologies. It is known that the above radio frequency based positioning systems (Wi-Fi, Bluetooth, RFID and GSM) have relatively low cost. However, the accuracy of the above system may be on the order of meters (from 1 to 3 meters), which may be too low for precise control and navigation of indoor robots, UAVs or vehicles. On the other hand, other indoor positioning systems based on UWB, ultrasonic and infrared technology provide high positioning accuracy, but the deployment infrastructure may be too expensive and therefore not suitable for a wide range of applications.

In the past few years, some research has been conducted to explore visible light localization. Most of these visible light location systems can be measured based on received signal strength (RSS). However, these measurements may be unrealistic in reality due to unpredictable transmitted optical power and user mobility, which in turn significantly limits the positioning accuracy of the system. On the other hand, some angle of arrival (AOA) based methods have also been proposed previously to achieve a high precision visible light positioning system. However, it needs to have a large The image sensor of the pixel is used as a detector. Compared to conventional photodiodes, an image detector may have higher cost and lower detection rate. In order to achieve a reliable positioning accuracy and overcome the impact of mobility, some phase shift measurement based positioning systems have been proposed and studied. However, these systems assume that both the transmitter (Txs) and the receiver (Rxs) are ideally synchronized, which may be difficult to achieve in reality, or based on infrared and complex receiver uplinks to achieve a high level of positioning accuracy, which cannot be Integration into lighting facilities based on downlinks. To date, there are no commercially viable indoor positioning systems that are reliable, low cost, provide high level of positioning accuracy, and support specific mobility rates.

Some embodiments address two issues, namely cost and/or precision. Some embodiments may be related to low cost, high accuracy, and stability of an indoor positioning system (through the use of a light-emitting diode lighting facility). The public grade visible light location system provides a specific mobility rate, such as a robot or other various applications. With the help of the above technologies, more applications based on high-precision positioning can be developed for a large number of consumer markets. As the inventors of GPS systems may not have envisioned a wide range of GPS applications currently in use, it is impossible to predict all future applications of a public-grade visible light location system.

A local sync and a continuous sine wave modulation scheme can be employed to minimize system complexity. Through the above technology, the receiver (Rx) does not need to be synchronized with the complex transmitter (Tx), and can only use the received downlink link signal to estimate the positioning information. Since no synchronization is required between the complex transmitter and receiver, the complexity of the system can be significantly reduced.

Some embodiments may be suitable for applications in areas where radio frequency is restricted or prohibited, such as airports, compared to current radio frequency based positioning systems. Harbour and hospital. A further advantage is that the light radiation does not penetrate walls or opaque objects. Therefore, some embodiments are applicable to a secure and privacy location system.

Based on the wide-ranging applications of light-emitting diode lighting systems in buildings and underground spaces in the near future, some embodiments (with white light-emitting diode-based visible light positioning technology) can provide high indoor accuracy ( A solution for robotic navigation and other various positioning-enabled applications in the order of centimeters. It is conceivable that the accuracy of the cent positioning can be an essential part of the next generation of indoor positioning and navigation systems for indoor robots, autonomous vehicles, UAVs, UGVs and the like. Packaging and commercialization may not be a problem, as all required devices are relatively inexpensive and commercially available, and the principles of operation can be relatively simple. On the other hand, the dual function of the existing illumination LEDs can also significantly reduce the cost of the proposed system. All required components can be low cost commercial electronic devices.

Including some inexpensive devices in some embodiments may allow for cost effective mass production. Consumer applications for indoor location information may be unlimited. These applications include navigation and positioning not only for indoor robots, autonomous vehicles, unmanned aviation vehicles (UAVs), unmanned ground vehicles (UGVs), but also some high precision. Positioning based industrial applications.

Some research results can stimulate the next generation of indoor high-precision positioning and scientific research in the field of navigation systems. Some embodiments may provide a strong foundation for future development of accuracy, cost, and reliability within an indoor positioning system.

When the invention is presented in a specific manner and by specific implementation Various changes and details may be employed without departing from the spirit and scope of the invention, as set forth in the appended claims. The scope of the present invention is intended to be included within the scope of the appended claims.

100‧‧‧ Positioning System

102‧‧‧Transmitter array

104a, 104b‧‧‧ visible light positioning unit

106a-106d‧‧‧Lighting diode

108‧‧‧ Receiver

110‧‧‧Detector

Claims (21)

A positioning system comprising: a transmitter array comprising a plurality of visible light positioning units, each of the visible light positioning units comprising a plurality of light emitting diodes, each of the light emitting diodes configured to transmit a visible light, the visible light comprising causing the visible light An identification portion associated with the light emitting diode, and a phase data portion; and a receiver including a detector configured to receive the light emitting diodes of each of the visible light positioning units The visible light transmitted by the body; wherein the receiver is configured to select one of the visible light positioning units based on the identification portions of the visible light; and wherein the receiver is further configured to be based on The phase data portions of the visible light transmitted by the light-emitting diodes of the selected visible light positioning unit determine a position of the receiver. The positioning system of claim 1, wherein the phase data portions of the visible light transmitted by different light-emitting diodes of each of the visible light positioning units are modulated to have substantially the same The initial phase and the substantially different frequencies. The positioning system of claim 2, wherein the phase portions of the visible light that are transmitted by the different light-emitting diodes of the selected visible light positioning unit and the visible light received by the detector are With different phase offsets. The positioning system according to any one of claims 1 to 3, wherein the identification portion of the visible light and the phase data portion transmitted by each of the light-emitting diodes are converted into basic On the same frequency. The positioning system according to any one of claims 1 to 4, wherein the identification portion of the visible light transmitted by each of the light-emitting diodes is one of binary phase shift keying Identification data is modulated. The positioning system of any one of clauses 1 to 5, wherein the receiver is configured to ignore the transmission of the light-emitting diodes of the visible light positioning units that are not selected The phase data portion of the visible light. The positioning system of any one of clauses 1 to 6, wherein the receiver is further configured to select the selected visible light location of the visible light positioning units based on the complex signal noise ratio The signal noise ratios of the light-emitting diodes of the visible light positioning units are determined before the unit. The positioning system of claim 7, wherein the receiver is further configured to determine the signal to noise ratios before determining the position of the receiver. The positioning system of claim 7 or claim 8, wherein the signal to noise ratio of the light emitting diodes of the selected visible light positioning unit is higher than the selected visible light The signal to noise ratios of the light emitting diodes of the positioning unit. The positioning system as described in any one of claims 1 to 9 The receiver is configured to determine the location of the receiver by differential phase shift measurement and a trilateration algorithm. The positioning system according to any one of claims 1 to 10, wherein a plurality of visible light phase data portions and a second visible light position transmitted by the plurality of light emitting diodes of the first visible light positioning unit are used. The phase data portion of the plurality of visible light transmitted by the plurality of light-emitting diodes of the unit has substantially different initial phases. The positioning system of any one of clauses 1 to 11, wherein the detector is a photodiode. A transmitter array includes: a plurality of visible light positioning units, each of the visible light positioning units includes a plurality of light emitting diodes, each of the light emitting diodes configured to transmit a visible light, the visible light comprising causing the visible light and the light emitting diode An identification portion associated with the body, and a phase data portion; wherein the visible light transmitted by the light emitting diodes of each of the visible light positioning units is configured to be received by one of the receivers; The identifying portions of the visible light are configured to be used by the receiver to select one of the visible light positioning units of the visible light positioning units; and wherein the light emitting diodes of the selected visible light positioning unit are The phase data portions of the transmitted visible light are configured to be used by the receiver to determine a location of the receiver. A receiver includes: a detector configured to receive each of a plurality of visible light positioning units Seeing a plurality of visible light transmitted by the plurality of light emitting diodes of the light positioning unit, each of the visible light includes an identification portion that causes the visible light to be associated with a light emitting diode, and a phase data portion; wherein the receiver is configured Selecting one of the visible light positioning units based on the identification portions of the visible light; wherein the receiver is further configured to transmit based on the light emitting diodes of the selected visible light positioning unit The phase data portions of the visible light determine a position of the receiver. A method of constructing a positioning system, comprising: providing a transmitter array, the transmitter array comprising a plurality of visible light positioning units, each of the visible light positioning units comprising a plurality of light emitting diodes, each of the light emitting diodes configured to transmit a visible light comprising: an identification portion that causes the visible light to be associated with the light emitting diode, and a phase data portion; and a receiver, the receiver including a detector configured to Receiving the visible light transmitted by the light emitting diodes of each of the visible light positioning units; wherein the receiver is configured to select one of the visible light positioning units for visible light positioning based on the identification portions of the visible light And wherein the receiver is further configured to determine a position of the receiver based on the phase data portions of the visible light transmitted by the light emitting diodes of the selected visible light positioning unit. A method of constructing a positioning system as described in claim 15 of the patent application, The portions of the phase data of the visible light transmitted by the different light emitting diodes of each of the visible light positioning units are modulated to have substantially the same initial phase and have substantially different frequencies. The method of constructing a positioning system according to claim 15 or claim 16, wherein the different light-emitting diodes of the selected visible light positioning unit transmit and receive the same by the detector The phase data portions of visible light have different phase offsets. The method for constructing a positioning system according to any one of claims 15 to 17, wherein the identification portion of the visible light and the phase data portion transmitted by each of the light-emitting diodes are Tune to essentially the same frequency. The method for constructing a positioning system according to any one of claims 15 to 18, wherein the identification portion of the visible light transmitted by each of the light-emitting diodes is subjected to a binary phase shift. One of the keying identifies the data to be modulated. The method of constructing a positioning system according to any one of claims 15 to 19, wherein the receiver is configured to ignore the light-emitting diodes of the visible light positioning units that are not selected. The phase data portions of the visible light transmitted. A method for determining a position of a receiver, comprising: receiving, by a detector of the receiver, a plurality of visible light transmitted by a plurality of light-emitting diodes of each visible light positioning unit of the plurality of visible light positioning units, wherein each of the visible light Is transmitted through a light emitting diode, and the visible light includes a light that causes the visible light to be associated with the light emitting diode Identifying a portion, and a phase data portion; selecting, by the receiver, one of the visible light positioning units based on the identification portions of the visible light; and transmitting, by the receiver, based on the selected visible light The phase data portions of the visible light transmitted by the light-emitting diodes of the unit determine the position of the receiver.