Indoor mobile phone positioning method based on TDOA (Time difference of Arrival)

Abstract

The invention discloses an indoor mobile phone positioning method based on TDOA (Time difference of Arrival). Sound wave beacons and wireless beacons are transmitted and received through utilization of a microphone and a wireless network card built in a smart phone; distance measurement and positioning are carried out according to the time difference of transmission of the wireless signals and the sound wave signals; positioning base stations periodically transmit and broadcast the sound wave beacons and the wireless beacons and record transmitting time stamps of the signals through a drive layer; a positioning mobile phone receives the wireless beacons and the sound wave beacons of the nearby positioning base stations and records the arrival time stamps of the beacons through the drive layer; on the basis of the four time stamps, the positioning mobile phone can calculate the distance to the positioning base stations; frequency modulation is carried out on the sound wave beacons based on an MAC address; the modulation method can be used for identifying source addresses of the beacons; and the positioning mobile phone can calculate own position coordinate through adoption of a maximum likelihood method when measuring the arrival distance of the three positioning base stations. The method is independent of special hardware, time synchronization does not need to be carried out between system nodes, and the method has the advantages of simplicity, feasibility, high positioning precision and high stability.

Description

technical field [0001] The invention relates to an indoor positioning technology, in particular to a TDOA-based indoor mobile phone positioning method. Background technique [0002] With the widespread popularization of mobile smart terminals and wireless networks, the application of Location Based Services (LBS) has been increasing day by day, and it is playing an increasingly important role in driving navigation, smart management, social network, security monitoring and many other fields. effect. Among them, terminal positioning is the key premise of location services. Only when terminal location information is obtained, various applications and controls of physical and information fusion can be effectively switched. For example, some large indoor places (such as parking lots, logistics warehouses, mines, prisons, archaeological sites, and exhibition centers) all need to locate people or objects in order to realize navigation, monitoring, and management. In addition, in ...

AI Technical Summary

Problems solved by technology

However, due to signal blocking and insufficient positioning accuracy, the above two mobile phone positioning systems cannot be applied to closed indoor environments

Signal fingerprint positioning based on WiFi network is currently the most common indoor wireless positioning method. However, the signal fingerprint positioning algorithm needs to establish an offline map in advance, which has problems such as large labor consumption, and the accuracy and stability still cannot meet the needs of most indoor positioning scenarios.

However, some short-distance positioning systems based on Zigbee, Bluetooth or RFID are limited in their application and promotion due to their small coverage and dependence on special hardware.

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