WO2022170634A1 - Line-of-sight path recognition based indoor positioning method independent of device - Google Patents

Abstract

A line-of-sight path recognition based indoor positioning method independent of a device, comprising step 1: dividing a monitoring area to be a plurality of small grids, an initial value of each small grid being 0; step 2: determining whether each communication link between receiving ends is a line-of-sight path; step 3: if the communication link is not the line-of-sight path, calculating a Fresnel area of the communication link, and adding 1 to all grid values in the Fresnel area; and step 4: traversing all the communication links, a grid having the maximum value being the most likely position of a target object, and if the number of grids having the maximum value is greater than one, taking the center of a plurality of grid positions as the position of the target object.

Description

A device-independent line-of-sight path recognition indoor positioning method technical field

The invention relates to a device-independent line-of-sight path identification indoor positioning method, which belongs to the technical field of indoor positioning and navigation.

Background technique

The wide application and deployment of WIFI technology has spawned many WIFI-based indoor positioning technologies, and wireless indoor positioning technology has also been widely used in many other aspects, such as robot indoor navigation, indoor games, intelligent human-computer interaction shopping guide, health care system, etc. There are two main types of WiFi indoor positioning methods: device-based active positioning methods and device-independent passive positioning methods. Active positioning requires the target object to carry a device and communicate data with the detection device to infer position information based on the signal or phase. Passive positioning does not require the target object to carry wireless transmission equipment. It is based on the interference of the target itself to the wireless signal, and the position information is inferred by measuring the signal attenuation degree on the interfered link. Since the target object does not need to carry related equipment, it can be more widely used in various occasions, such as elderly health care.

technical problem

Existing device-independent positioning technologies usually require pre-training. By collecting the signal strength of a specific reference point and a fixed access AP, and matching information such as the degree of signal attenuation to a specific point after adding a target, the fingerprint-based matching positioning method and shell Yessian estimation algorithm, etc., infer the location information of the target object. The current technology achieves pre-training, which increases the difficulty of technical application, hinders the promotion, and is easily disturbed by the complex and changeable indoor environment, resulting in a decrease in positioning accuracy. Therefore, how to achieve reliable and high-precision indoor positioning in the field of device-independent passive positioning technology without prior training has become an important problem that we need to solve.

technical solutions

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beneficial effect

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Embodiments of the present invention

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Industrial Applicability

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Claims (3)

A device-independent line-of-sight path identification indoor positioning method, comprising the following steps: step 1: dividing a monitoring area into several small squares, and the initial value of each square is 0; step 2: judging the receiving Whether the communication link between the ends is a line-of-sight path; Step 3: If it is not a line-of-sight path, calculate the Fresnel area of the link, and add 1 to all the grid values in the Fresnel area; Step 4: Traverse all communications Link, the square with the maximum value, the square position is the most likely position of the target object; if there are multiple squares, the center of the multiple square positions is taken. The first step includes: 1a: deploying multiple groups of wireless transceivers in the monitoring area, any group of transceiver nodes can communicate with each other, and the monitoring area is divided into several small squares of the same size; 1b: when a target appears in a When the group of transceivers is in a straight line, it is determined that the communication link at this time is non-line-of-sight; 1c: Through two non-line-of-sight communication links, find the overlapping area where the two non-line-of-sight paths pass through, and the target can be determined position; Step 2 includes: 2a: use the phase difference information of the multiple antennas of the wireless device to realize the line-of-sight path identification; 2b: the receiving end will generate a phase offset measurement error in the process of receiving the signal, which can be eliminated by the dual-antenna phase difference Phase measurement error, set a threshold that can separate line-of-sight and non-line-of-sight paths, and use binary hypothesis testing to determine that the phase difference belongs to the range of line-of-sight or non-line-of-sight phase differences; Step 3 includes: 3a: Each channel The state information is represented by the measured values of the amplitude and phase of each sub-carrier; 3b: In the two environments of line-of-sight and non-line-of-sight, since the non-line-of-sight is obstructed by the target object, the signal propagation path is more random than the line-of-sight, The viewing distance can be judged by the difference in phase and amplitude; 3c: is the actual phase difference between the two antennas; δ is the time delay at the receiving end; β is the unknown phase offset; Z represents the monitoring noise; The sampling difference of the root antenna, δ remains unchanged when the channel is stable. β is the constant phase difference of the two antennas, the part caused by the carrier has been cancelled, and the rest can be cancelled by the phase shift operation; 3d: By obtaining a series of channel state information samples of M data packets, use the ρ factor to represent the change value of the phase:   ; 3e: Use binary hypothesis to test line-of-sight (H0) and non-line-of-sight (H1), namely: H0: ρ<ρik and H1: ρ>ρik, where ρik is the set value; 3f: The Fresnel area is the transmission and reception area Between the antennas, the ellipsoid area is formed by the travel difference between the straight path of the radio wave and the polyline path, with the position of the transceiver antenna as the focus and the straight path as the axis; 3g: When the target object is located at the Fresnel of the transceiver link In the area, when the sum of the distance between the receiver and the target and the distance between the transmitter and the target < the sum of the distance between the receiver and the transmitter + half of the distance between the straight path and the discounted path, the weight is 1, otherwise it is 0 ; Step 4 includes: 4a: traverse all communication links, and the square with the maximum value, then the square position is the most likely position of the target object; 4b: if there are multiple squares, then take the center of the multiple square positions the most likely location of the target object.