A method for origin-synchronized ultraviolet light localization

Abstract

This invention discloses a transmitter-synchronized ultraviolet (UV) positioning method. The method is applicable to UV positioning with any three transmitters. First, each transmitter determines the signals from the other two transmitters. Each transmitter calculates the time difference between the transmission synchronization signals of the other two transmitters. After transmitting the synchronization sequence, each transmitter waits for a fixed time and then transmits a new sequence carrying the time difference to the receiver. The receiver determines the received signal using the correlation peak synchronization method and records the time of receiving the signals from the three transmitters. Based on the received times and time differences of the three transmitter signals, the path time difference from each transmitter to the receiver is calculated. Finally, the position coordinates of the receiver are obtained by solving the time difference over time (TDOA). This method can achieve transmitter time synchronization for UV positioning without relying on external time and related equipment, and has high synchronization accuracy.

Description

Technical Field

[0001] This invention relates to the field of wireless optical communication technology, and in particular to an ultraviolet light positioning method with transmitter synchronization. Background Technology

[0002] Wireless positioning technology determines the location of an object by measuring certain parameters of radio waves and using specific algorithms. These parameters typically include the radio wave's transmission time, amplitude, phase, and angle of arrival. Time Difference of Arrival (TDA) positioning is one common algorithm. Ultraviolet (UV) 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 zone as a carrier wave. At the transmitting end, an information electrical signal is modulated onto this UV carrier wave. The modulated UV carrier signal propagates using atmospheric scattering. At the receiving end, an optical communication link is established by capturing and tracking the UV beam. The information signal is then extracted through photoelectric conversion and demodulation processing. Therefore, it features high speed, anti-interference, and non-line-of-sight characteristics.

[0003] Current TDOA ultraviolet positioning systems encounter the problem of difficulty in synchronizing the transmitters. For example, local wired connections can achieve transmitter synchronization, but this is limited by the location and difficult to implement in long-distance positioning environments. Satellite time synchronization is also limited by the location and affected by weather and other factors, and the synchronization accuracy is not high. Summary of the Invention

[0004] The purpose of this invention is to provide a method for ultraviolet light positioning with synchronous transmission. This method can achieve synchronization of the transmission time of ultraviolet light positioning without relying on external time and related equipment, and has high synchronization accuracy.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for ultraviolet light localization with synchronized transmitters, applicable to ultraviolet light localization at any three transmitters, specifically comprising:

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

[0008] Step 2: When transmitter 2 determines that a signal has been received, it sends a synchronization sequence to transmitters 1 and 3. Transmitters 1 and 3 determine that a signal has been received using the correlation peak synchronization method, and each records the time of signal reception as t. 21 , t 23 ;

[0009] Step 3: When transmitter 3 determines that a signal has been received, it sends a synchronization sequence to transmitters 1 and 2. Transmitters 1 and 2 determine that a signal has been received using the correlation peak synchronization method and each records the time of signal reception as t. 31 , t 32 ;

[0010] Step 4: Each transmitter calculates the time difference between the transmission synchronization signals of the other two transmitters and adds the time difference as information to its own synchronization sequence to form a new synchronization sequence for each transmitter.

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

[0012] Step 6: Based on the times when the three transmitter signals were received as recorded in Step 5 and the time difference obtained in Step 4, calculate the travel time difference from transmitter 1 and transmitter 2 to the receiver, and the travel time difference from transmitter 2 and transmitter 3 to the receiver.

[0013] Step 7: Then, use TDOA to solve for the position coordinates of the receiving end.

[0014] As can be seen from the technical solution provided by the present invention, the above method can achieve the synchronization of the start time of ultraviolet light positioning, without relying on external time and related equipment, and has high synchronization accuracy. At the same time, the emitted light path will hardly cause interference, and the light paths emitted at different times have no intersection in the time domain. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic flowchart of the ultraviolet light positioning method for origination synchronization provided in an embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments, and do not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0018] like Figure 1 The diagram shown is a schematic flowchart of an ultraviolet light positioning method with synchronized transmitters provided in an embodiment of the present invention. The method is applied to ultraviolet light positioning of any three transmitters and specifically includes:

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

[0020] Step 2: When transmitter 2 determines that a signal has been received, it sends a synchronization sequence to transmitters 1 and 3. Transmitters 1 and 3 determine that a signal has been received using the correlation peak synchronization method, and each records the time of signal reception as t. 21 , t 23 ;

[0021] Step 3: When transmitter 3 determines that a signal has been received, it sends a synchronization sequence to transmitters 1 and 2. Transmitters 1 and 2 determine that a signal has been received using the correlation peak synchronization method and each records the time of signal reception as t. 31 , t 32 ;

[0022] At this point, each originating point has identified signals from the other two originating points.

[0023] Step 4: Each transmitter calculates the time difference between the transmission synchronization signals of the other two transmitters and adds the time difference as information to its own synchronization sequence to form a new synchronization sequence for each transmitter.

[0024] In step 4, if the distances between the three transmitters are equal, each transmitter i will subtract the time of the signals from the other two transmitters to obtain the time difference of the transmission synchronization signal between the other two transmitters. Specifically: transmitter i obtains t 31 -t 21 The second originator obtained t 32 -t 12 The 3rd originating point yielded t 23 -t 13 Let them be t respectively. i i = 1, 2, 3;

[0025] Otherwise, the travel time difference needs to be deducted, and the travel time between origin i and origin j is denoted as tt. i，j Then the travel time difference that needs to be deducted from origin 1 is tt. 1,3 -tt 1,2 Finally, the time difference between the synchronization signals obtained by transmitter 1 from the other two transmitters is: t1 = t 31 -t 21 -(tt 1，3 -tt 1,2 ).

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

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

[0028] Step 6: Based on the times when the three transmitter signals were received as recorded in Step 5 and the time difference obtained in Step 4, calculate the travel time difference from transmitter 1 and transmitter 2 to the receiver, and the travel time difference from transmitter 2 and transmitter 3 to the receiver.

[0029] In this step, ts2-ts1-t3 is calculated as the distance time difference from transmitter 1 and transmitter 2 to receiver; where ts2 is the time recorded by receiver to receive signal from transmitter 2; ts1 is the time recorded by receiver to receive signal from transmitter 1; and t3 is the time difference of transmission synchronization signal between the other two transmitters calculated by transmitter 3.

[0030] Calculate ts3-ts2-t1, which is the distance time difference from origin 2 and origin 3 to the receiving end, denoted as tts. 23 Similarly, we can obtain tts 31 and TTS 12 ;

[0031] Where ts3 is the time recorded by the receiving end when it receives the signal transmitted by the transmitting end 3; ts2 is the time recorded by the receiving end when it receives the signal transmitted by the transmitting end 2; and t1 is the time difference between the transmission synchronization signals between the other two transmitting ends calculated by the transmitting end 1.

[0032] Step 7: Then, use TDOA to solve for the position coordinates of the receiving end.

[0033] The specific process in this step is as follows:

[0034] Let the coordinate of the starting point i be (X i Yi ), i = 1, 2, 3; the coordinates of the receiving end (observation point) are (X, Y), and the distance between the coordinates of the sending end i and the receiving end is . The difference in distance traveled from origin i to origin 1 to the receiver is Ri, 1 = Ri - R1 = ttsi1·c, where c is the speed of light. Therefore, we obtain the equation:

[0035]

[0036]

[0037] Furthermore:

[0038]

[0039]

[0040] After simplification, we obtain a system of two linear equations in two variables concerning the position coordinates (X, Y) of the receiving end:

[0041]

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

[0043] In practice, each transmitting end consists of an ultraviolet light emitter and a photomultiplier tube (PMT), while the receiving end consists of a PMT.

[0044] The correlation peak synchronization method calculates the correlation value of the received synchronization sequence, and the maximum value of the correlation value is the correlation peak value; finding the correlation peak value means that a 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 those skilled in the art.

[0046] The effectiveness of the method described in this embodiment of the invention is verified below. In this example, a simulated direct connection test was first performed on the positioning system. The signal was directly connected via a wire without using a PMT (Positioning Mediator). The data from the receiving end was transmitted to a personal PC for data processing. 106 sets of data were collected. The results are shown in Tables 1 and 2 below:

[0047] Table 1

[0048]

[0049] Table 2

[0050]

[0051] The results in Tables 1 and 2 show that the time difference error between any two transmitting and receiving ends is less than 30 ns, and the error of this time difference is 0 ns for nearly half of the data, which can be considered as having high accuracy.

[0052] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for ultraviolet light positioning with synchronized start-up, characterized in that, The method is applied to ultraviolet light localization at any three emitting ends, specifically including: Step 1: Transmitter 1 sends a synchronization sequence to Transmitter 2 and Transmitter 3. Transmitter 2 and Transmitter 3 receive the synchronization sequence and determine the received signal using the correlation peak synchronization method, and each records the time of receiving the signal as t. 12 , t 13 ; Step 2: When transmitter 2 determines that a signal has been received, it sends a synchronization sequence to transmitters 1 and 3. Transmitters 1 and 3 determine that a signal has been received using the correlation peak synchronization method, and each records the time of signal reception as t. 21 , t 23 ; Step 3: When transmitter 3 confirms the received signal, it sends a synchronization sequence to transmitters 1 and 2. Transmitters 1 and 2 confirm the received signal using the correlation peak synchronization method and each records the time of signal reception as t. 31 , t 32 ; Step 4: Each transmitter calculates the time difference between the transmission synchronization signals of the other two transmitters and adds the time difference as information to its own synchronization sequence to form a new synchronization sequence for each transmitter. In step 4, if the distances between the three transmitters are equal, each transmitter i will subtract the time of the signals from the other two transmitters to obtain the transmission synchronization signal time difference between the other two transmitters. Specifically: transmitter i obtains t 31 -t 21 The second originator obtained t 32 -t 12 The 3rd originating point yielded t 23 -t 13 Let them be t respectively. i i = 1, 2, 3; Otherwise, the travel time difference needs to be deducted, and the travel time between origin i and origin j is denoted as tt. i，j Then the travel time difference that needs to be deducted from origin 1 is tt. 1，3 -tt 1，2 Finally, the time difference between the transmission synchronization signals obtained by transmitter 1 from the other two transmitters is: t1 = t 31 -t 21 -(tt 1,3 -tt 1,2 ); Step 5: After sending the synchronization sequence, each transmitter waits for a set time, and then sends a new sequence carrying time difference information to the receiver. The receiver determines the received signal using the correlation peak synchronization method and records the time of receiving the three transmitter signals as ts. i i = 1, 2, 3; Step 6: Based on the times when the three transmitter signals were received as recorded in Step 5 and the time difference obtained in Step 4, calculate the travel time difference from transmitter 1 and transmitter 2 to the receiver, and the travel time difference from transmitter 2 and transmitter 3 to the receiver. Step 7: Then, use TDOA to solve for the position coordinates of the receiving end.

2. The ultraviolet light positioning method with synchronous transmission as described in claim 1, characterized in that, In step 6, ts2-ts1-t3 is calculated as the distance time difference from transmitter 1 and transmitter 2 to receiver; where ts2 is the time recorded by receiver to receive signal from transmitter 2; ts1 is the time recorded by receiver to receive signal from transmitter 1; and t3 is the time difference of transmission synchronization signal between the other two transmitters calculated by transmitter 3. Calculate ts3-ts2-t1, which is the distance time difference from origin 2 and origin 3 to the receiving end, denoted as tts. 23 Similarly, we can obtain tts 31 and TTS 12 ; Where ts3 is the time recorded by the receiving end when it receives the signal transmitted by the transmitting end 3; ts2 is the time recorded by the receiving end when it receives the signal transmitted by the transmitting end 2; and t1 is the time difference between the transmission synchronization signals between the other two transmitting ends calculated by the transmitting end 1.

3. The ultraviolet light positioning method with synchronous transmission as described in claim 1, characterized in that, In step 7, the specific process is as follows: Let the coordinate of the starting point i be (X i Y i ), i = 1, 2, 3; the position coordinates of the receiving end are (X, Y), and the distance between the sending end i and the receiving end is . The difference in distance traveled from origin i to origin 1 to the receiver is R. i，1 =R i -R1=tts i，1 ·c, where c is the speed of light, thus we obtain the equation: Furthermore: After simplification, we obtain a system of two linear equations in two variables concerning the position coordinates (X, Y) of the receiving end: Introducing a constant K i =X i 2 -Y i 2 Treating R1 as a constant, we solve the equation to obtain (X, Y), and then substitute the result back into the equation about R1 to obtain a quadratic equation in R1. After solving the equation, we substitute R1 back into the expression for (X, Y) to obtain the position coordinates (X, Y) of the receiving end.

4. The ultraviolet light positioning method with synchronous transmission as described in claim 1, characterized in that, Each transmitting end consists of an ultraviolet light emitter and a photomultiplier tube (PMT), and the receiving end consists of a photomultiplier tube (PMT).

5. The ultraviolet light positioning method with synchronous transmission according to claim 1, characterized in that, The correlation peak synchronization method calculates the correlation value of the received synchronization sequence, and the maximum value of the correlation value is the correlation peak value; finding the correlation peak value means that a synchronization signal has been received.

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