CN112782649A - Wireless optical positioning system based on serial port and photoelectric converter array - Google Patents
Wireless optical positioning system based on serial port and photoelectric converter array 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
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Abstract
The invention discloses a wireless optical positioning system based on a serial port and a photoelectric converter array, which comprises a transmitting end and a receiving end, wherein the transmitting end comprises a signal processing unit with the serial port, an LED and a driving circuit thereof. The receiving end comprises a plurality of photoelectric converters with different directional gains, an analog-to-digital converter group and a signal combining amplifier, and the output of the signal combining amplifier is sent to the serial port to extract the identity information or the coordinates of the optical base station; the output of the analog-to-digital converter group is sent to a signal processing unit to extract the incident angle of the optical signal and the coordinates of the receiver. The invention does not depend on a large amount of high-speed AD, does not require the signal processing unit to have high-speed operation capability, and has low cost and easy integration. The introduction of the signal combination amplifier improves the reliability of identity information extraction.
Description
Technical Field
The invention relates to a wireless optical positioning system based on a serial port and a photodiode array, belonging to the crossing field of information technology and automation technology.
Background
Radio frequency spectrum resources are precious: the wireless optical communication system has the advantages of large bandwidth, strong confidentiality, lighting function, no electromagnetic interference and the like; the wireless optical positioning system based on the incident angle can reach centimeter-level precision.
Existing wireless optical positioning systems are typically based on a camera or an array of photosensors. For a wireless optical positioning system based on a camera, due to the low sampling rate and the small capacity of an optical channel of the camera, the realization difficulty of the wireless optical positioning system is the identification of different LED base stations. In addition, the optical positioning system based on the camera also faces a problem that power consumption is difficult to reduce. For an optical positioning system based on an optoelectronic converter array, usually, the identity information of an LED base station is carried in a high-speed optical signal, and each optoelectronic converter needs to be equipped with an expensive high-speed Analog-to-digital (AD) converter to sample the optical signal, and then the signal processing unit identifies the identity code of the LED base station according to the sequence of sampled values. When the number of photoelectric converters is large, the total cost of AD may be high; in addition, the signal processing core must have the capability of receiving and processing multiple AD samples in real time, which further increases the system cost. Moreover, the signal-to-noise ratio of the output signal of the single-path photoelectric converter is low, and quantization noise is introduced into each path of AD, so that the identification code identification misjudgment rate based on the AD sampling value is high. Finally, the large number of high-speed ADs and powerful processors also do not facilitate reduction of power consumption and volume compression.
Disclosure of Invention
The purpose of the invention is as follows: in order to solve the problems of high cost, difficult integration and difficult identity code extraction of a wireless optical positioning system based on a photoelectric converter array, the invention provides a low-cost and stable wireless optical positioning system based on a serial port and the photoelectric converter array. In addition, an analog circuit, namely a signal merging amplifier is adopted to merge multiple paths of optical signals with low signal to noise ratio, and the signals with high signal to noise ratio are generated and then sent to a serial port to carry out identity recognition of the LED base station, so that the accuracy of the identity recognition is improved.
The technical scheme is as follows: in order to achieve the purpose, the invention adopts the technical scheme that:
a wireless optical positioning system based on a serial port and a photoelectric converter array comprises a transmitting end and a receiving end, wherein the transmitting end comprises a signal processing unit with the serial port, an LED and a driving circuit thereof. The receiving end comprises a plurality of photoelectric converters with different directional gains, an analog-to-digital converter group and a signal merging amplifier, wherein:
the transmitting terminal modulates the optical signal by using the serial port signal, embeds the identity information or the coordinate of the optical base station into the modulated optical signal, and transmits the obtained modulated optical signal through the LED and the driving circuit thereof.
The photoelectric converter receives modulated optical signals emitted by the LED and the driving circuit thereof to obtain photoelectric signal vectors; the photoelectric signal vector is received by an analog-to-digital converter group on a signal combination amplifier and a receiving end signal processing unit; the signal merging amplifier merges the photoelectric signal vectors and then sends the merged photoelectric signal vectors to a serial port receiving end of a receiving end signal processing unit, and the serial port receiving end transmits the received information to the receiving end signal processing unit; and the analog-to-digital converter group sends the sampling signal after the photoelectric signal vector is sampled to the receiving end signal processing unit.
The receiving end signal processing unit identifies the optical positioning base station or the coordinates thereof which currently sends information according to the photoelectric signals received by the serial port receiving end; and the receiving end signal processing unit extracts the incident angle of the optical signal according to the photoelectric signal sent by the analog-to-digital converter group, and obtains the coordinates of the receiver through the incident angle of the optical signal and the corresponding optical positioning base station or the coordinates thereof.
The signal output by the signal combiner has high signal-to-noise ratio, and the voltage is amplified to the standard voltage of the serial port, so that the signal can be directly received by the serial port of the receiver, and the receiving end signal processing unit identifies the optical positioning base station or the coordinates thereof which currently sends information according to the photoelectric signal received by the serial port receiving end.
The process of identifying the LED identity code and the process of AD sampling are jointly performed. Only when the LED identity code is correctly identified, the AD sample currently acquired by the receiver can be matched with the coordinate of a certain base station for solving the coordinate of the receiver. AD samples that do not match the base station coordinates cannot reflect the receiver's location information. Because the adopted AD converter group and the signal processing unit are low-cost devices, the identity code of the base station cannot be solved through the AD samples. In a word, the isolated signal combining amplifier and the AD converter group cannot complete the two functions of identification code identification and multi-path photocurrent signal sampling.
Preferably: when more than two optical base stations exist, each base station only occupies part of the time slots to send the identity information or the coordinates of the base station, and other time slots are used for other optical base stations to send the identity information or the coordinates.
Preferably: the signal merging amplifier merges the photoelectric signal vectors by a method of summing or selecting a maximum value, and amplifies the merged photoelectric signal vectors to an acceptable voltage range of a serial port receiving end of a receiving end signal processing unit.
Preferably: the photoelectric converter is a basic component capable of converting optical signals into weak electric signals.
Preferably: the photoelectric converter comprises one of a photodiode, a photoresistor, a phototriode and a photomultiplier.
Preferably: the photoelectric converters with different directional gains are realized by adopting different inclination angles, lenses with different optical parameters and gratings with different optical parameters.
The working principle of the invention is as follows:
the optical signal sent by the transmitter is directly regulated and controlled by the serial port signal, and can be directly received by the serial port of the receiving end through level conversion at the receiving end, namely, the transparent transmission of the serial port based on the optical signal is realized. The optical signal can be embedded into the identity code or coordinates of the LED base station as an input parameter to the receiver positioning algorithm.
A set of photoelectric converters with different directional gains is used for distinguishing the angles of incident light. That is, when the direction of the incident light changes, the combination of the electrical signals generated by the photoelectric converter changes. According to the gain parameters of the photoelectric converter in different directions and the output signal amplitude of the photoelectric converter, the incident angle or direction vector of the optical signal can be obtained through table look-up or geometric calculation, and then the coordinates of the receiver can be determined by utilizing the existing optical positioning algorithm.
The signal combining amplifier combines each path of weak optical signals to obtain an output signal with a high signal-to-noise ratio, so that the successful receiving probability of the serial port on the identity code or the coordinate is improved.
Compared with the prior art, the invention has the following beneficial effects:
the invention realizes the serial port transparent transmission of the transmitting end and the receiving end through the optical channel, realizes the identification of the LED base station identity code or the acquisition of the base station coordinate under the condition of not using an expensive high-speed AD group, reduces the cost of the AD group and the signal processing, reduces the system volume and reduces the power consumption. In addition, the signal merging amplifier is adopted to merge multiple paths of photoelectric signals with low signal-to-noise ratio, so that signals with high signal-to-noise ratio are obtained, and the reliability of obtaining identity codes and base station coordinates is improved.
Drawings
Fig. 1 is a block diagram of a wireless optical positioning system based on a serial port and a photoelectric converter array according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a photoelectric converter with different directional gains according to an embodiment of the present invention;
fig. 3 is a positioning flowchart provided in an embodiment of the present invention.
Detailed Description
The present invention is further illustrated by the following description in conjunction with the accompanying drawings and the specific embodiments, it is to be understood that these examples are given solely for the purpose of illustration and are not intended as a definition of the limits of the invention, since various equivalent modifications will occur to those skilled in the art upon reading the present invention and fall within the limits of the appended claims.
A wireless optical positioning system based on a serial port and a photoelectric converter array is shown in figures 1 and 3 and comprises a transmitting end and a receiving end, wherein the transmitting end comprises a signal processing unit with the serial port, an LED and a driving circuit thereof. The receiving end comprises a plurality of photoelectric converters with different directional gains, an Analog-to-digital (AD) converter group and a signal merging amplifier, wherein:
the transmitting terminal modulates the optical signal by using the serial port signal, embeds the identity information or the coordinate of the optical base station into the modulated optical signal, and transmits the obtained modulated optical signal through the LED and the driving circuit thereof. The transmitting terminal signal processing unit modulates the optical signal through the serial port and transmits the identity information or the coordinates of the base station to the receiving terminal through an optical channel. Common signal processing units with serial ports are single-chip microcomputers (such as Atmega328P, 8051, STM3) or large-scale Programmable arrays (FPGAs).
The photoelectric converter receives the modulated light signals emitted by the LED and the driving circuit thereof to obtain photoelectric signal vectors. And the photoelectric signal vector is received by the analog-to-digital converter group on the signal combination amplifier and the receiving end signal processing unit. The signal output by the signal combiner has high signal-to-noise ratio, and the voltage is amplified to the standard voltage of the serial port, so that the signal can be directly received by the serial port of the receiver, and the identity code of the LED base station can be directly acquired. And the analog-to-digital converter group samples the photoelectric signal vector and then sends the photoelectric signal vector to the receiving end signal processing unit. And the receiving end signal processing unit extracts the incident angle of the optical signal according to the photoelectric signal sent by the analog-to-digital converter group, and obtains the coordinates of the receiver through the incident angle of the optical signal and the corresponding optical positioning base station or the coordinates thereof. It is worth emphasizing that after the LED base station identity code is correctly received, the AD sampling values in a subsequent period of time are both the signal sampling values of the current LED base station by default, and therefore, the process of the LED base station identity code identification and the process of the AD sampling are a combined process and must supplement each other.
The photoelectric converter is a basic component capable of converting optical signals into weak electric signals. Comprises one of a photodiode, a photoresistor, a phototriode and a photomultiplier. The photoelectric converters with different directional gains are realized by adopting different inclination angles, lenses with different optical parameters and gratings with different optical parameters. The optical signal is received by a plurality of photoelectric converters having different directional gains, and a photoelectric signal vector is generated. The photoelectric signal vector is sent to a low-speed AD group of a signal processing unit and is connected with a signal merging amplifier. The low-speed AD group is common equipment of a mainstream singlechip, and both Atmega328P and STM32 are provided with the AD group. The signal combining amplifier may be implemented by an operational amplifier, for example, using an analog adder circuit. As shown in fig. 2, the photoelectric converterThe group output voltage value is proportional to the luminous flux on the photosensitive surface, i.e. the photoelectric signal vector. The inputs to the AD group are low signal-to-noise ratio photo-electric signal vectors whose sample amplitudes reflect the received light signal energy in a particular direction. For example, if there are 3 photoelectric converters on the receiver, their normal vector directions are (-0.4082,0.7071,0.5774)T，(-0.4082,-0.7071,0.5774)T，(0.8165,-0.0000,0.5774)TThe directional gain of a single photoelectric converter is
g＝cosθ
Where θ is the angle between the incident light and the normal direction of the photoelectric converter. Suppose that the current three AD sample values are (115,115,781)TThen, the incident light direction can be calculated by the method in "B.Zhu, Z.Zhu, Y.Wang and J.Cheng," Optical orthogonal Angle-of-Arrival Estimator With Complementary photometodies, "in Journal of Lightwave Technology, vol.37, No.13, pp.2932-2945,1July1, 2019" ((0.68, 0, 0.73))T。
Assuming that the receiver moves in the z 0 plane, the receiver coordinates of (-2.79,0,0) can be obtained by the positioning method in "B.Zhu, Z.Zhu, Y.Wang and J.Cheng", "Optical angular of-Arrival With complete Complementary radios" in Journal of Lightwave Technology, vol.37, No.13, pp.2932-2945,1July1,2019T. In addition, other known angular positioning algorithms may be used to calculate the receiver coordinates after the incident light direction is measured.
The signal combination amplifier combines the photoelectric signal vectors and then sends the combined photoelectric signal vectors to a serial port receiving end of a receiving end signal processing unit, and the receiving end signal processing unit identifies the optical positioning base station or the coordinates thereof which currently sends information according to the photoelectric signals received by the serial port receiving end. The signal merging amplifier merges the photoelectric signal vectors by a method of summing or selecting a maximum value, and amplifies the merged photoelectric signal vectors to an acceptable voltage range of a serial port receiving end of a receiving end signal processing unit. The output of the signal combination amplifier is a photoelectric signal with high signal-to-noise ratio, the photoelectric signal can be directly introduced into a serial port of the signal processing unit after level conversion, the LED identity code or the coordinate is extracted by built-in serial port processing hardware and stored in a serial port cache, and finally the serial port cache is stored in the signal processing unit. For example, the identity code of the LED currently sending the signal may be "123" with coordinates (0,0, 3).
When more than two optical base stations exist, each base station only occupies a small number of time slots to send the identity information or the coordinates of the base station, and other time slots are used for other optical base stations to send the identity information or the coordinates.
The invention extracts the identity information or coordinates of the optical base station by sending the output of the signal merging amplifier to the serial port; the output of the AD group is sent to the signal processing unit, and the optical signal incidence angle and the receiver coordinate are extracted through a positioning algorithm. The introduction of the signal combination amplifier improves the reliability of identity information extraction.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (6)
1. A wireless optical positioning system based on a serial port and a photoelectric converter array is characterized by comprising a transmitting end and a receiving end, wherein the transmitting end comprises a signal processing unit with the serial port, an LED and a driving circuit thereof; the receiving end comprises a plurality of photoelectric converters with different directional gains, an analog-to-digital converter group and a signal merging amplifier, wherein:
the transmitting terminal modulates an optical signal by using the serial port signal, embeds the identity information or the coordinate of the optical base station into the modulated optical signal, and transmits the obtained modulated optical signal through the LED and the driving circuit thereof;
the photoelectric converter receives modulated optical signals emitted by the LED and the driving circuit thereof to obtain photoelectric signal vectors; the photoelectric signal vector is received by an analog-to-digital converter group on a signal combination amplifier and a receiving end signal processing unit; the signal merging amplifier merges the photoelectric signal vectors and then sends the merged photoelectric signal vectors to a serial port receiving end of a receiving end signal processing unit, and the serial port receiving end transmits the received information to the receiving end signal processing unit; the analog-to-digital converter group sends a sampling signal obtained by sampling a photoelectric signal vector to a receiving end signal processing unit;
the receiving end signal processing unit identifies the optical positioning base station or the coordinates thereof which currently sends information according to the photoelectric signals received by the serial port receiving end; and the receiving end signal processing unit extracts the incident angle of the optical signal according to the photoelectric signal sent by the analog-to-digital converter group, and obtains the coordinates of the receiver through the incident angle of the optical signal and the corresponding optical positioning base station or the coordinates thereof.
2. The wireless optical positioning system based on the serial port and the photoelectric converter array as claimed in claim 1, wherein: when more than two optical base stations exist, each base station only occupies part of the time slots to send the identity information or the coordinates of the base station, and other time slots are used for other optical base stations to send the identity information or the coordinates.
3. The wireless optical positioning system based on the serial port and the photoelectric converter array as claimed in claim 2, wherein: the signal merging amplifier merges the photoelectric signal vectors by a method of summing or selecting a maximum value, and amplifies the merged photoelectric signal vectors to an acceptable voltage range of a serial port receiving end of a receiving end signal processing unit.
4. The wireless optical positioning system based on the serial port and the photoelectric converter array as claimed in claim 3, wherein: the photoelectric converter is a basic component capable of converting optical signals into weak electric signals.
5. The wireless optical positioning system based on the serial port and the photoelectric converter array as claimed in claim 4, wherein: the photoelectric converter comprises one of a photodiode, a photoresistor, a phototriode and a photomultiplier.
6. The wireless optical positioning system based on the serial port and the photoelectric converter array as claimed in claim 5, wherein: the photoelectric converters with different directional gains are realized by adopting different inclination angles, lenses with different optical parameters and gratings with different optical parameters.
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| CN111342907A (en) * | 2020-03-19 | 2020-06-26 | 东南大学 | Circuit with wireless optical communication signal diversity and incident light angle estimation functions |
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- 2021-01-22 CN CN202110085605.5A patent/CN112782649B/en active Active
Patent Citations (6)
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| US20010040713A1 (en) * | 2000-04-06 | 2001-11-15 | Shinichiro Haruyama | Receiving apparatus, transmitting apparatus, and communication system |
| WO2016050147A1 (en) * | 2014-09-30 | 2016-04-07 | 重庆长安汽车股份有限公司 | Adaptive reception device and method for led vehicle light communication |
| CN108572348A (en) * | 2018-06-06 | 2018-09-25 | 华南理工大学 | A kind of indoor visible light vision positioning method and its hardware system |
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