Indoor positioning method based on WiFi (Wireless Fidelity) fingerprints

Abstract

The invention discloses an indoor positioning method based on WiFi (Wireless Fidelity) fingerprints. The method comprises the steps of continuously acquiring RSSI (Received Signal Strength Indication) values of WiFi signals within a certain period of time for each known position point in a place to be positioned, preprocessing the acquired data, counting times num that each AP (Access Point) occurs in the signal sequence of a certain position point, deleting AP signal data with num which is smaller than half of the total length of the sequence, calculating the average value mu and the standard deviation delta of the preprocessed data, and storing the average value mu and the standard deviation delta in a database; and acquiring the RSSI values of the WiFi signals at a point to be positioned, uploading the RSSI values to a sever, matching the acquired data of the point to be positioned with values in the database by adopting a multilevel probability algorithm to obtain W position estimation values with the maximum probability and performing time averaging to obtain the position estimation of the point to be measured. Compared with the prior art, the method has the advantages that the positioning accuracy is guaranteed, the operability and the practicability of the system are improved, and the goal of accurate positioning at distance of 3m can be achieved.

Description

technical field [0001] The invention belongs to the technical field of indoor positioning, and in particular relates to an indoor positioning method based on WiFi fingerprints. Background technique [0002] A WiFi wireless network consists of an access point (AP) and a wireless network card. The AP is generally in a fixed position, and the signal it transmits contains information such as the global unique identifier of the hotspot, the network name, and the encryption method. By scanning, the mobile terminal can obtain the ID of the nearby hotspot, the name of the network, and the RSSI (Received Signal Strength Indication) of the location of the terminal. [0003] At present, most of the general-purpose WiFi indoor positioning technologies are based on IEEE802.11b / g protocol wireless local area network (WLAN) signal strength positioning technology, which are mainly divided into geometric measurement method and position fingerprint positioning method. The relative principle ...

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Problems solved by technology

[0003] At present, most of the general-purpose WiFi indoor positioning technologies are based on IEEE802.11b / g protocol wireless local area network (WLAN) signal strength positioning technology, which are mainly divided into geometric measurement method and position fingerprint positioning method. The relative principle is used to calculate the user's location, but the disadvantage is that special hardware measurement equipment is required, and the extreme complexity of the indoor radio propagation environment makes the prediction accuracy of the RSS propagation model of the geometric measurement method often low, and the positioning accuracy is not high, and the specific AP The location needs to be known in advance, which does not meet the actual application requirements; the general location fingerprint method has different receiving devices, which makes the received signal different, resulting in the wireless signal strength data collected in real time cannot be matched with the established location fingerprint database. The positioning accuracy is not high, which reduces the operability and practicability of the system

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