Ultraviolet light positioning method with synchronous transmitting end

Abstract

The invention discloses a transmitting end synchronous ultraviolet light positioning method, which is applied to ultraviolet light positioning of any three transmitting ends, and comprises the following steps of: firstly, determining signals from the other two transmitting ends by each transmitting end; each transmitting end calculates a synchronous signal transmitting time difference between the other two transmitting ends; each sending end waits for a fixed time after sending the synchronization sequence and then sends a new sequence carrying a time difference to the receiving end, and the receiving end determines received signals through a correlation peak synchronization method and respectively records the time when the signals of the three sending ends are received; according to the time of receiving the signals of the three transmitting ends and the time difference, calculating to obtain the distance time difference from each transmitting end to the receiving end; and the position coordinates of the receiving end are obtained through TDOA solution. According to the method, the transmitting end time synchronization of ultraviolet light positioning can be realized, the method does not depend on external time and related equipment, and the synchronization precision is relatively high.

Description

Technical Field

[0001] The invention relates to the technical field of wireless optical communication, and in particular to a transmitting end synchronized ultraviolet light positioning method. Background Art

[0002] Wireless positioning technology measures some parameters of radio waves and determines the position of the measured object according to a specific algorithm. The measurement parameters generally include the transmission time, amplitude, phase and arrival angle of the radio waves. The time difference of arrival positioning algorithm is one of the common positioning algorithms. Ultraviolet communication is a wireless optical communication technology based on atmospheric scattering and absorption. Its basic principle is to use the spectrum of the solar blind area as the carrier, modulate the information electrical signal at the transmitting end and load it onto the ultraviolet light carrier. The modulated ultraviolet light carrier signal is propagated by atmospheric scattering. At the receiving end, an optical communication link is established by capturing and tracking the ultraviolet light beam, and the information signal is extracted through photoelectric conversion and demodulation. Therefore, it has the characteristics of high-speed, anti-interference and non-line-of-sight.

[0003] The current TDOA ultraviolet positioning system encounters the problem of difficulty in synchronizing the transmitter. For example, local wired connection can achieve synchronization of the transmitter, but it is limited by the site and difficult to achieve in a long-distance positioning environment. The use of satellite timing is also limited by the site and is affected by more factors such as weather, and the synchronization accuracy is not high. Summary of the invention

[0004] The purpose of the present invention is to provide a method for ultraviolet light positioning with synchronization of the source, which can realize synchronization of the source time of ultraviolet light positioning, does not rely on external time and related equipment, and has high synchronization accuracy.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A method for locating ultraviolet light with synchronized emission ends, the method being applied to locating ultraviolet light of any three emission ends, specifically comprising:

[0007] Step 1: Transmitter 1 sends a synchronization sequence to transmitters 2 and 3. Transmitters 2 and 3 receive the synchronization sequence and determine the received signal by using the correlation peak synchronization method, and each records the time of receiving the signal as t 12 , t 13 ;

[0008] Step 2: When determining the received signal, transmitter No. 2 sends a synchronization sequence to transmitter No. 1 and transmitter No. 3. Transmitters No. 1 and No. 3 determine the received signal through the correlation peak synchronization method, and each records the time of receiving the signal as t 21 , t 23 ;

[0009] Step 3: When the transmitting end 3 determines the received signal, it sends a synchronization sequence to the transmitting end 1 and the transmitting end 2. The transmitting end 1 and the transmitting end 2 determine the received signal through the correlation peak synchronization method, and each records the time of receiving the signal as t 31 , t 32 ;

[0010] Step 4: Each transmitting end calculates the time difference of sending synchronization signals between the other two transmitting ends, and adds the time difference as information to the respective synchronization sequence to form a new synchronization sequence for each transmitting end;

[0011] Step 5: Each transmitting end waits for a set time after sending the synchronization sequence, and then sends a new sequence carrying the time difference information to the receiving end. The receiving end determines the received signal through the correlation peak synchronization method, and records the time of receiving the three transmitting end signals as ts. i , i=1,2,3;

[0012] Step 6: Calculate the time difference between the transmission ends 1 and 2 and the receiving end, and the time difference between the transmission ends 2 and 3 and the receiving end according to the time of receiving the three transmission end signals recorded in step 5 and the time difference obtained in step 4;

[0013] Step 7: Use TDOA to solve the location coordinates of the receiving end.

[0014] It can be seen from the technical solution provided by the present invention that the above method can realize the synchronization of the starting time of ultraviolet light positioning, and does not rely on external time and related equipment, has high synchronization accuracy, and the optical paths emitted at the same time will hardly cause interference, and the optical paths emitted at different times have no intersection in the time domain. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0016] Figure 1 A schematic flow chart of a method for ultraviolet light positioning with synchronization of the transmitting end provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, which does not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] like Figure 1 FIG. 1 is a flow chart of a method for ultraviolet light positioning with synchronization of transmitting ends provided in an embodiment of the present invention. The method is applied to ultraviolet light positioning of any three transmitting ends, and specifically includes:

[0019] Step 1: Transmitter 1 sends a synchronization sequence to transmitters 2 and 3. Transmitters 2 and 3 receive the synchronization sequence and determine the received signal by using the correlation peak synchronization method, and each records the time of receiving the signal as t 12 , t 13 ;

[0020] Step 2: When determining the received signal, transmitter No. 2 sends a synchronization sequence to transmitter No. 1 and transmitter No. 3. Transmitters No. 1 and No. 3 determine the received signal through the correlation peak synchronization method, and each records the time of receiving the signal as t 21 , t 23 ;

[0021] Step 3: When the transmitting end 3 determines the received signal, it sends a synchronization sequence to the transmitting end 1 and the transmitting end 2. The transmitting end 1 and the transmitting end 2 determine the received signal through the correlation peak synchronization method, and each records the time of receiving the signal as t 31 , t 32 ;

[0022] At this point each transmitter has determined the signals from the other two transmitters.

[0023] Step 4: Each transmitting end calculates the time difference of sending synchronization signals between the other two transmitting ends, and adds the time difference as information to the respective synchronization sequence to form a new synchronization sequence for each transmitting end;

[0024] In step 4, if the distances between the three transmitting ends are equal, each transmitting end i will subtract the time of the signals of the other two transmitting ends from the time of the signals to obtain the time difference of the transmission synchronization signals between the other two transmitting ends. Specifically, transmitting end 1 obtains t 31 -t 21 , the sender 2 gets t 32 -t 12 , the sender No. 3 gets t 23 -t 13 , respectively denoted as t i , i=1,2,3;

[0025] Otherwise, the travel time difference needs to be deducted, and the travel time between the originating number i and the originating number j is tt i，j , then the time difference that needs to be deducted from the originating point 1 is tt 1,3 -tt 1,2 Finally, the time difference between the transmission synchronization signals of the other two transmitting ends obtained by transmitting end 1 is: t1 = t 31 -t 21 -(tt 1，3 -tt 1,2 ).

[0026] Step 5: Each transmitting end waits for a set time after sending the synchronization sequence, and then sends a new sequence carrying the time difference information to the receiving end. The receiving end determines the received signal through the correlation peak synchronization method, and records the time of receiving the three transmitting end signals as ts. i , i=1,2,3;

[0027] In this step, the set time should ensure the completion of step 4 to avoid conflicts in the optical path.

[0028] Step 6: Calculate the time difference between the transmission ends 1 and 2 and the receiving end, and the time difference between the transmission ends 2 and 3 and the receiving end according to the time of receiving the three transmission end signals recorded in step 5 and the time difference obtained in step 4;

[0029] In this step, ts2-ts1-t3 is calculated as the time difference between the transmission end No. 1 and the transmission end No. 2 and the receiving end; wherein ts2 is the time recorded by the receiving end when the signal sent by the transmission end No. 2 is received; ts1 is the time recorded by the receiving end when the signal sent by the transmission end No. 1 is received; t3 is the time difference of the transmission synchronization signal between the other two transmission ends calculated by the transmission end No. 3;

[0030] Calculate ts3-ts2-t1 to get the time difference between the sender 2 and the sender 3 to the receiver, denoted as tts 23 , and similarly get tts 31 and tts 12 ;

[0031] Among them, ts3 is the time recorded by the receiving end when the signal sent by transmitting end No. 3 is received; ts2 is the time recorded by the receiving end when the signal sent by transmitting end No. 2 is received; t1 is the time difference of the sending synchronization signal between the other two transmitting ends calculated by transmitting end No. 1.

[0032] Step 7: Use TDOA to solve the location coordinates of the receiving end.

[0033] In this step, the specific process is as follows:

[0034] The coordinates of the originating point i are (X i , Yi ), i = 1, 2, 3; the position coordinates of the receiving end (observation point) are (X, Y), and the distance between the coordinates of the transmitting end i and the receiving end is The difference between the distances from the source i and the source 1 to the receiving end is Ri,1=Ri-R1=ttsi1·c, where c is the speed of light, so the equation is:

[0035]

[0036]

[0037] And then:

[0038]

[0039]

[0040] After arranging and simplifying, we get a set of linear equations of two variables about the position coordinates (X, Y) of the receiving end:

[0041]

[0042] The constant K introduced here i =X i 2 -Y i 2 ; Treat R1 as a constant, solve the equation to get (X, Y), and then substitute the result back into the equation about R1 to get a quadratic equation about R1; after solving the equation, substitute R1 back into the expression of (X, Y) to get the position coordinates of the receiving end (X, Y).

[0043] In a specific implementation, each transmitting end is composed of an ultraviolet light emitter and a photomultiplier tube (PMT), and the receiving end is composed of a PMT.

[0044] The correlation peak synchronization method is to obtain the correlation value of the received synchronization sequence, and the maximum value of the correlation value is the correlation peak value; when the correlation peak value is found, it is considered that the synchronization signal has been received.

[0045] It is worth noting that the contents not described in detail in the embodiments of the present invention belong to the prior art known to professional and technical personnel in the field.

[0046] The effect of the method described in the embodiment of the present invention is verified below. In this example, the positioning system is firstly simulated directly connected to test, without using PMT, the signal is directly connected with a wire, and the data at the receiving end is transmitted to the personal PC for data processing. The collected data is 106 groups. The results are shown in Table 1 and Table 2 below:

[0047] Table 1

[0048]

[0049] Table 2

[0050]

[0051] From the results in Table 1 and Table 2, we know that the error of the time difference between any two transmitting ends and receiving ends is less than 30ns, and the error of the time difference of nearly half of the data is 0ns, which can be considered to have high accuracy.

[0052] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. The information disclosed in the background technology section of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A method for ultraviolet positioning with synchronous transmission, characterized in that: The method is applied to ultraviolet light positioning of any three originating ends, and specifically includes: Step 1: Transmitter 1 sends a synchronization sequence to transmitters 2 and 3. Transmitters 2 and 3 receive the synchronization sequence and determine the received signal by using the correlation peak synchronization method, and each records the time of receiving the signal as t 12 , t 13 ; Step 2: When determining the received signal, transmitter No. 2 sends a synchronization sequence to transmitter No. 1 and transmitter No.

3. Transmitters No. 1 and No. 3 determine the received signal through the correlation peak synchronization method, and each records the time of receiving the signal as t 21 , t 23 ; Step 3: When the transmitting end 3 determines the received signal, it sends a synchronization sequence to the transmitting end 1 and the transmitting end 2. The transmitting end 1 and the transmitting end 2 determine the received signal through the correlation peak synchronization method, and each records the time of receiving the signal as t 31 , t 32 ; Step 4: Each transmitting end calculates the time difference of sending synchronization signals between the other two transmitting ends, and adds the time difference as information to the respective synchronization sequence to form a new synchronization sequence for each transmitting end; Step 5: Each transmitting end waits for a set time after sending the synchronization sequence, and then sends a new sequence carrying the time difference information to the receiving end. The receiving end determines the received signal through the correlation peak synchronization method, and records the time of receiving the three transmitting end signals as ts. i , i=1,2,3; Step 6: Calculate the time difference between the transmission ends 1 and 2 and the receiving end, and the time difference between the transmission ends 2 and 3 and the receiving end according to the time of receiving the three transmission end signals recorded in step 5 and the time difference obtained in step 4; Step 7: Use TDOA to solve the location coordinates of the receiving end.

2. The method for ultraviolet positioning with synchronous transmission end according to claim 1, characterized in that: In step 4, if the distances between the three transmitting ends are equal, each transmitting end i will subtract the time of the signals of the other two transmitting ends from the time of the signals to obtain the time difference of the transmission synchronization signals between the other two transmitting ends. Specifically, transmitting end 1 obtains t 31 -t 21 , the sender 2 gets t 32 -t 12 , the sender No. 3 gets t 23 -t 13 , respectively denoted as t i , i=1,2,3; Otherwise, the travel time difference needs to be deducted, and the travel time between the originating number i and the originating number j is tt i，j , then the time difference that needs to be deducted by the originator No. 1 is tt 1，3 -tt 1，2 Finally, the time difference between the transmission synchronization signals of the other two transmitting ends obtained by transmitting end 1 is: t1 = t 31 -t 21 -(tt 1，3 -tt 1，2 ).

3. The method for ultraviolet positioning with synchronous transmission end according to claim 1, characterized in that: In step 6, ts2-ts1-t3 is calculated as the time difference between the transmission end No. 1 and the transmission end No. 2 and the receiving end; wherein ts2 is the time recorded by the receiving end when the signal sent by the transmission end No. 2 is received; ts1 is the time recorded by the receiving end when the signal sent by the transmission end No. 1 is received; t3 is the time difference of the transmission synchronization signal between the other two transmission ends calculated by the transmission end No. 3; Calculate ts3-ts2-t1 to get the time difference between the sender 2 and the sender 3 to the receiver, recorded as tts 23 , and similarly get tts 31 and tts 12 ; Among them, ts3 is the time recorded by the receiving end when the signal sent by transmitting end No. 3 is received; ts2 is the time recorded by the receiving end when the signal sent by transmitting end No. 2 is received; t1 is the time difference of the sending synchronization signal between the other two transmitting ends calculated by transmitting end No.

1.

4. The method for ultraviolet positioning with synchronous transmission end according to claim 1, characterized in that: In step 7, the specific process is: The coordinates of the originating point i are (X i , Y i ), i = 1, 2, 3; the position coordinates of the receiving end are (X, Y), and the distance between the coordinates of the sending end i and the receiving end is The difference between the distances from the source i and the source 1 to the receiving end is Ri,1=Ri-R1=ttsi1·c, where c is the speed of light, so the equation is: And then: After arranging and simplifying, we get a set of linear equations of two variables about the position coordinates (X, Y) of the receiving end: The constant K introduced here i =X i 2 -Y i 2 ; Treat R1 as a constant, solve the equation to get (X, Y), and then substitute the result back into the equation about R1 to get a quadratic equation about R1; after solving the equation, substitute R1 back into the expression of (X, Y) to get the position coordinates of the receiving end (X, Y).

5. The method for ultraviolet positioning with synchronous transmission end according to claim 1, characterized in that: Each transmitting end is composed of an ultraviolet light emitter and a photomultiplier tube PMT, and the receiving end is composed of a photomultiplier tube PMT.

6. The method for ultraviolet positioning with synchronous transmission end according to claim 1, characterized in that: The correlation peak synchronization method is to obtain the correlation value of the received synchronization sequence, and the maximum value of the correlation value is the correlation peak value; when the correlation peak value is found, it is considered that the synchronization signal has been received.

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