Triangular positioning system and method based on visible light

A technology of triangulation positioning and visible light, which is applied in positioning, radio wave measurement systems, measuring devices, etc., can solve the problems affecting ranging and positioning accuracy, lack of accurate and operable light incident angle measurement methods, difficult signal synchronization and time measurement and other problems, to achieve the effect of convenient synchronization and control, and simple hardware

Inactive Publication Date: 2016-04-06

WUHAN POST & TELECOMM RES INST CO LTD

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Problems solved by technology

Various methods have their own advantages and disadvantages: In the RSS-based measurement scheme, the received optical power is usually affected by factors such as the brightness of the light source, the scattering and reflection of signal light, the angle of light transmission and reception, and background light interfe...

Abstract

The invention belongs to the technical field of communication and space positioning, and especially relates to a triangular positioning system and method based on visible light. A to-be-positioned target employs an LED lamp for transmitting a visible light signal, and a signal receiving end employs a plurality of light detectors with known coordinates and receives a light signal from an LED. The light detectors enables measured signals to be gathered in a processing unit, and the phase difference is calculated, thereby obtaining an optical path difference from the LED to the plurality of light detectors. The coordinates of the signal receiving end can be calculated according to the triangle geometric principle. According to the invention, a transmission end is simple in hardware, and can be extended to a plurality of positioning targets. Moreover, all calculation and processing can be completed at the receiving end, thereby facilitating the synchronization and control. Therefore, the system and method are low in cost and are wide in application range.

Application Domain

Position fixation

Technology Topic

PhysicsOptical path +7

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[0017] The present invention will be further described in detail below in conjunction with the drawings and embodiments.

[0018] Such as figure 1 As shown, the target to be positioned uses LED lights to send visible light signals, and the signal receiving end has at least 3 light detectors with known coordinates to simultaneously receive light signals from the LED lights. figure 1 Among them, D1, D2, and D3 are 3 unevenly distributed photodetectors. The sending frequency of the LED light at the sending end is ω 1 , The initial phase is q 1 Sine wave, namely sin(ω 1 t+q 1 ). There are two different optical detectors D1 and D2 at the receiving end, and the optical signal received by D1 is expressed as: S 1 =A 1 sin(ω 1 t+ω 1 t 1 +q 1 ), where A 1 Is the gain, t 1 It is the transmission delay of the optical signal to the optical detector D1. The optical signal received by the optical detector D2 is expressed as: S 2 =A 2 sin(ω 1 t+ω 1 t 2 +q 1 ), where A 2 Is the gain, t 2 It is the transmission delay of the optical signal to the optical detector D2.

[0019] After the receiving end receives the signal, the S 1 S 2 Phase shift can be obtained S 1 * = A 1 c o s ( ω 1 t + ω 1 t 1 + q 1 ) S 2 * = A 2 c o s ( ω 1 t + ω 1 t 1 + q 1 ) , At the same time get the amplitude A 1 A 2. Calculation S 1 S 2 * - S 2 S 1 * = A 1 A 2 s i n ( ω 1 ( t 2 - t 1 ) ) Can determine sin(ω 1 (t 2 -t 1 ))the size of. In ω 1 Known circumstances, t 2 -t 1 There are multiple possible values, select the one that matches the possible value according to the distance range. In order to improve the measurement accuracy, the system can change different ω 1 Calculate t multiple times 2 -t 1 Take multiple averages.

[0020] Select two different photodetectors for multiple measurements, and the distance difference between the LED lamp and the different photodetectors can be obtained. For example, the distance between the LED and D1 and D2 is L 12 =c(t 2 -t 1 ), the distance difference between D2 and D3 is L 23 =c(t 2 -t 3 ), the distance between D1 and D3 is L 13 =c(t 1 -t 3 ), where c is the speed of light.

[0021] At a certain moment, if the distance between the LED light and D1 and D2 is known to be L 12 , It can be seen that the LED light is located with D1 and D2 as the focus, and L 12 On the hyperboloid with the length of the real axis. Similarly, if it is known that the distance between the LED light and 3 different photodetectors is L 12 , L 23 , L 13 , 3 single curved surfaces can be obtained. According to the triangular geometric solution equation, 1-2 intersection points can be obtained, and obviously unreasonable intersection coordinates are eliminated. As shown in the figure, the position below the photodetector cannot be located above the photodetector The coordinates of the intersection point, you can determine that the LED lamp coordinates are located at the intersection point above the three single curved surfaces.

[0022] The error on the transmission path from the optical detector at the receiving end to the processing unit needs to be eliminated through digital transmission. All detection results at the receiving end need to be aggregated to the processing unit for processing and calculation, and finally the positioning result is obtained. The phase difference of the detection signal directly determines the size of the measurement distance, so it is necessary to pre-calibrate the transmission time of each optical detector to the processing unit to strictly ensure the synchronization of the detection signal at the receiving end.

[0023] The present invention is not limited to the above-mentioned embodiments. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also regarded as the protection of the present invention. Within range. The content not described in detail in this specification belongs to the prior art known to those skilled in the art.

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Classification and recommendation of technical efficacy words

simple hardware

Triangular positioning system and method based on visible light

AI-Extracted Technical Summary

Problems solved by technology

Abstract

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Examples

Example Embodiment

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Description & Claims & Application Information

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