Indoor positioning and recognition system based on surface acoustic wave technology and positioning and identification method thereof

Abstract

The present invention discloses an indoor positioning and recognition system based on a surface acoustic wave technology and a positioning and recognition method thereof. A surface acoustic wave tag is a single-ended dual-channel delay line type structure. First two reflection gratings are positioning reflection gratings, and the last six reflection gratings are code reflection gratings, and phasestepping pulse position coding is used. A reader connects three reader antennas by using a three-point switch, and the three reader antennas are located at three fixed positions. Before a system is positioned, a relationship between a distance and signal strength is calibrated. When positioning is performed, signal intensity of a first echo pulse of the tag is used as positioning information, two-dimensional coordinates of a positioning target are obtained by a three-side positioning method, and coding information of the positioning target is obtained by using a delay and a phase of six echopulses. Features of the present invention are as follows: The tag is purely passive, influence of indoor multipath effect can be eliminated, an integrated function of positioning and recognition can be implemented, and system costs are reduced by a structure of connecting three antennas by using one reader are reduced.

Description

Technical field: [0001] The invention relates to an indoor positioning and identification system based on surface acoustic wave technology and a positioning and identification method thereof, belonging to the field of wireless sensing and radio frequency identification. Background technique: [0002] Satellite positioning systems such as the American GPS, China's Beidou, European Galileo, and Russian GLONASS have high positioning accuracy outdoors, but they are inaccurate or even impossible to locate indoors. Current indoor positioning includes WIFI positioning, Bluetooth positioning, ultra-wideband (Ultra-Wide Band, UWB) positioning and other solutions, usually based on "Received Signal Strength Indication (RSSI)", "Time of Arrival (TOA) )” and “Angle of Arrival (AOA)” to achieve positioning. [0003] Compared with TOA and AOA, indoor positioning technology based on RSSI has been widely used due to its low hardware complexity and easy implementation, but there are the foll...

AI Technical Summary

Problems solved by technology

In a complex indoor environment, electromagnetic waves will reflect when they reach walls and objects other than the positioning target. The multipath effect will cause great interference to the received signal and seriously affect the positioning accuracy.

[0005] (2) In order to realize indoor two-dimensional positioning, the current hardware system needs at least three signal receivers, which is expensive

[0006] (3) At present, the positioning device attached to the positioning target usually adopts an active method, which has the trouble of regularly replacing the battery, and is not suitable for extreme indoor environments such as high temperature and high pressure, flammable and explosive

It is characterized by a wide positioning area, but it is necessary to ensure the anti-collision performance between multiple surface acoustic wave devices, and the mobile terminal is active, and the battery needs to be replaced regularly. It is not suitable for extreme environments such as high temperature and high pressure, flammable and explosive.

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