CN113229802A - Single-device WiFi indoor height detection method based on phased array principle - Google Patents

Single-device WiFi indoor height detection method based on phased array principle Download PDF

Info

Publication number
CN113229802A
CN113229802A CN202110249544.1A CN202110249544A CN113229802A CN 113229802 A CN113229802 A CN 113229802A CN 202110249544 A CN202110249544 A CN 202110249544A CN 113229802 A CN113229802 A CN 113229802A
Authority
CN
China
Prior art keywords
phase
scanning
distance
antenna
phased array
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202110249544.1A
Other languages
Chinese (zh)
Inventor
杨晨
马晓宇
赵昕禹
陈祖豪
惠维
赵季中
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xian Jiaotong University
Original Assignee
Xian Jiaotong University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xian Jiaotong University filed Critical Xian Jiaotong University
Priority to CN202110249544.1A priority Critical patent/CN113229802A/en
Publication of CN113229802A publication Critical patent/CN113229802A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/107—Measuring physical dimensions, e.g. size of the entire body or parts thereof
    • A61B5/1072—Measuring physical dimensions, e.g. size of the entire body or parts thereof measuring distances on the body, e.g. measuring length, height or thickness
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/0002—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network
    • A61B5/0015—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network characterised by features of the telemetry system
    • A61B5/0022—Monitoring a patient using a global network, e.g. telephone networks, internet

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Animal Behavior & Ethology (AREA)
  • Biophysics (AREA)
  • Pathology (AREA)
  • Veterinary Medicine (AREA)
  • Public Health (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Dentistry (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

The invention discloses a single-device WiFi indoor human height detection method based on a phased array principle. The adopted technical scheme is as follows: under the indoor environment, an antenna array is deployed, angle measurement is carried out by utilizing the thought of a phased array, scanning time is reduced by utilizing scanning from coarse granularity to fine granularity, angle measurement precision is improved by utilizing an equal signal method, and the angles of different parts of the body can be obtained through the steps. Then, the distance measurement is carried out on different body parts by using a multi-frequency method, the angle information and the distance information are combined to obtain a body trunk heat map, and the purpose of height detection is achieved.

Description

Single-device WiFi indoor height detection method based on phased array principle
Technical Field
The invention belongs to the field of wireless sensing, and particularly relates to a non-binding WiFi indoor height detection method based on a single device by using a phased array principle.
Background
Indoor perception means perception of some information of people in indoor environment, and can be used in environments such as airport halls, exhibition halls, warehouses, supermarkets, libraries, underground parking lots, mines and the like. Expert scholars have proposed many indoor perception technical solutions, mainly divided into two broad categories, computer vision based and wireless location based.
When the computer vision is used for perception, a camera needs to be installed indoors, and the position of a target and the characteristics of the target need to be identified in an image processing mode. Although higher indoor positioning accuracy can be achieved by using computer vision, only sight distance propagation is enabled because light cannot pass through obstacles. Moreover, the indoor positioning based on computer vision has high calculation complexity, is easily influenced by background colors, and the privacy of the user can be invaded by the camera.
With the development of wireless communication technology, emerging wireless network technologies, such as WiFi, bluetooth, etc., are widely used in offices, homes, etc. In the wireless-based sensing technology, the method mainly includes three methods, wherein the fingerprint method is the most widely applied algorithm at present, and mainly includes two stages, firstly, a database (namely, the influence of different users on wireless data at different positions) is established by collecting data (such as RSS, CSI and the like) offline, and then, in the online sensing stage, the target real-time wireless data is matched with the data in the fingerprint database to realize sensing. However, such systems have some inherent disadvantages, firstly the process of data acquisition is very cumbersome, and secondly small changes in the surrounding environment can lead to unsuccessful matching and even the need to rebuild the database. The second method is ranging, which generally measures the time of flight of electromagnetic waves to locate and sense the target, such as directly measuring the time of flight using FMCW or indirectly finding the time of flight using phase, but it is difficult to accurately measure the time of flight, which requires some predefined actions of the target at predefined positions. The third is an angle measurement method, which utilizes a music algorithm to obtain the angle between a target and an antenna array, and carries out convergence sensing through the angles between a plurality of antenna arrays and the target.
In general, the existing indoor sensing systems are imperfect and have some defects and shortcomings. The wireless sensing technology is the mainstream of indoor sensing due to the advantages of wall wearing and non-binding. However, fingerprint-based methods require extensive training, time-of-flight-based methods require user intervention, and goniometric-based methods require multiple devices. The invention combines angle measurement and distance measurement, and provides a WiFi indoor height detection method of single equipment by using a phased array principle.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a WiFi indoor height detection method based on a phased array principle, aiming at the indoor height detection problem, and without training in advance.
In order to achieve the above object, a schematic flow chart of the technical scheme adopted by the invention is shown in fig. 1, and comprises the following steps:
1) constructing an antenna array system: the system model used for height detection is a phased array system formed by antennas, namely a plurality of antenna units are arranged in a straight line to form a uniform linear array, a shifter is added on each antenna, and the phase of the antenna is controlled by the shifter, so that the effect of the phased array can be achieved.
2) Angle measurement is carried out on the target: a group of antennas are used to form an antenna array, a narrow beam can be formed by adjusting the phases of different antennas according to the phased array principle, and when the feeding phase of the antennas is changed, the direction of the beam is changed, so that a beam scanning phased array system can be formed.
2.1) to determine the orientation of different parts of the body torso, a coarse-grained scan is first performed. Two antennas are used to form a scanning system with a wide beam, and when the beam is directed to a target, the echo energy is high. From the echo energy, the approximate extent of the different parts of the body torso can be determined.
2.2) fine-grained scanning. The number of antennas is continuously increased, more and more antennas are used to form a scanning system with narrower beams, and the next scanning is only performed within the possible range determined by the previous antenna array scanning.
2.3) improving the precision. In order to achieve a high accuracy with a small number of antennas, the equal signal method is used. When fine-grained scanning is performed, if the echo energies in the two directions are approximately the same, it is indicated that the target is located on the bisector of the two angles.
3) Multi-target ranging: and after the direction of the target is measured, aiming at each target, ranging by using a multi-frequency method.
3.1) in different time slots, the antenna sends radio frequency signals with different frequencies, so that phase lag generated by distance under different frequencies can be obtained, and phase ambiguity exists in the phase at the moment.
3.2) to the phase ambiguity number niTraversing search is carried out, and n corresponding to the minimum error under the least square criterion is foundi。
3.3) according to niThe true position of the target is calculated.
4) Multi-target positioning: by said step 2) accurate angle measurements can be made for different parts of the body torso and by said step 3) accurate distance measurements can be made for each part. The position of each part can be obtained by combining the angle information and the distance information.
The premise that the beam scanning system is adopted to carry out multi-person angle measurement in the step 2) is that the angles between different parts of the trunk of the body and the antenna array are generally different in an indoor environment, so that the different parts of the trunk of the body can be distinguished through angle measurement.
In the step 2.1), two antennas are used to form a scanning system with a wider beam, so that the scanning granularity is larger and the scanning can be performed quickly.
The step 2.2) of continuously increasing the number of the antennas means that for a uniform linear array, the middle antenna is selected to perform first phased array scanning; then, one antenna is added to each of the left and right sides, scanning is performed within the range determined for the first time, and the like is performed until all the antennas are used.
The principle in step 2.2) is that the main lobe width of the beam is inversely proportional to the number of antennas, i.e., the larger the number of antennas, the narrower the main lobe width of the beam after the beam synthesis is performed. The narrower the main lobe width of the beam, the smaller the scanning granularity, the longer the scanning time, and the higher the scanning accuracy.
The principle of the equal signaling method in step 2.3) is to use two identical beams partially overlapping each other, which is their pattern with reference to fig. 4. Referring to fig. 5(a), if the target is in the direction of the overlap axis OA of the two beams, the received signal strength of the two beams is equal, otherwise referring to fig. 5, one beam receives a higher signal strength than the other. Therefore OA is called equal signal axis. When the echo signals received by the two wave beams are equal, the direction pointed by the equal signal axis is the direction of the target. Referring to FIG. 5(c) if the object is in the OB direction, the echo of beam 2 is stronger than that of beam 1; referring to fig. 5(b), when the object is in the OC direction, the echo of beam 2 is weaker than that of beam 1. Therefore, the direction of the target deviating from the equal signal axis can be judged by comparing the strength of the two wave beam echoes, and the size of the deviating equal signal axis can be estimated by a table look-up method.
In step 3.1), the transmitting signals with different frequencies is to transmit signals with different frequencies in the target direction determined in step 2).
In the step 3.1), the relationship between the distance and the phase is as follows:
Figure BDA0002965426650000041
wherein the content of the first and second substances,
Figure BDA0002965426650000042
is a phase lag due to distance, since it is periodic by 2 π
Figure BDA0002965426650000043
May contain n 2 pi, i.e. there is a phase ambiguity problem, and the distance corresponding to each 2 pi is:
Figure BDA0002965426650000044
the phase ambiguity number n in the step 3.2)iRefers to the number of 2 π contained in the actual phase, so the actual distance is:
Figure BDA0002965426650000045
the error in the step 3.2) refers to traversing different n under different frequenciesiThe error of the distance R is calculated, and when the error is minimum, the corresponding group niI.e. the corresponding phase ambiguity numbers at different frequencies.
Compared with the existing wireless sensing technology, the height detection method and the height detection device can detect the height by using a single device without training in advance. The invention uses the antenna array to measure the angle, uses the method of scanning from coarse granularity to fine granularity to reduce the scanning time, and uses the equal signal method to improve the angle measurement precision. The invention transmits a plurality of signals with different frequencies, and utilizes the different time delay phases of the signals with different frequencies to accurately measure the distance of single equipment. The height detection is carried out on the target in an indoor environment by a method combining angle measurement and distance measurement.
The invention can complete the height detection of a single person only by a wireless receiving and transmitting antenna array.
The invention adopts the equal signal method to measure the angle, and the angle measurement precision is higher than that of the traditional maximum signal method because when the target is positioned near the equal signal axis, if the target is slightly deviated from the equal signal axis, the intensity of the two signals is obviously changed.
The invention can judge the direction of the target deviating from the equal signal axis according to the strength of the signals received by the two wave beams, and is convenient for automatic angle measurement.
The multi-frequency ranging method adopted in the invention solves the problem of phase ambiguity, and can carry out accurate positioning by using a single device.
Drawings
FIG. 1 is a positioning flow diagram of the present invention;
FIG. 2 is a schematic of a uniform linear array;
FIG. 3 is a uniform linear array simulated directional diagram;
FIG. 4 is a schematic illustration of an isobeam method beam;
FIG. 5 is a graph showing the size of echoes received using the iso-beam method;
FIG. 6(a) is a two beam pattern;
FIG. 6(b) is the difference beam response;
FIG. 6(c) is for a beam;
FIG. 7 is a schematic view of the positioning of the present invention;
Detailed Description
The invention is further explained below with reference to specific embodiments and the drawing of the description.
The invention aims to provide a wireless-based unbound height detection system in an indoor environment aiming at the condition that the existing indoor sensing technology is lack in height detection, the system does not need to perform a large amount of training to establish a database by referring to a flow shown in the figure, only needs to deploy a certain number of antennas in the indoor environment, performs angle measurement by utilizing the thought of a phased array, then performs distance measurement by utilizing a multi-frequency method, and combines angle and distance information to complete height detection.
The invention is completed by the following four steps:
step 1) constructing an antenna array system
The system model used for height detection is a phased array system formed by using antennas, namely, a group of antennas form an antenna array, a narrow beam can be formed by adjusting the phases of different antennas according to the phased array principle, and when the feeding phase of the antennas is changed, the direction of the beam is changed, so that the phased array system for beam scanning can be formed. Next, a system model of the phased array will be described in detail.
Referring to fig. 2, a plurality of antennas are arranged together in a certain manner to form an array antenna (or antenna array). The radiation of the array antenna may be superimposed by the radiation of multiple antennas within the array. It is related to the form, relative position, current distribution, etc. of each antenna. A phased array antenna refers to an antenna that electronically controls the phase of the antenna so that the array antenna can complete beam scanning or rotation in a spatial plane. The invention adopts a uniform linear array.
The uniform linear array is formed by aligning a plurality of antenna elements, each antenna element having a phase shifter for changing the phase relationship of signals between the small antennas. The current amplitudes of the antenna elements are the same, the phases are increased or decreased in a uniform proportion, and the antenna elements are arranged on a straight line at equal intervals.
FIG. 2 shows an N-element uniform linear array, the distance between two adjacent antennas is d, and the phase difference of the radiation fields of the adjacent array elements caused by the distance between the adjacent antennas is
Figure BDA0002965426650000061
The phase difference of the excitation currents of the adjacent antennas is alpha. The electromagnetic wave radiated by the antenna element 1 is ahead of the antenna element 0
Figure BDA0002965426650000062
The electromagnetic wave radiated by the antenna element 2 is ahead of that radiated by the antenna element 1
Figure BDA0002965426650000063
The electromagnetic wave radiated by the antenna element 3 is ahead of that radiated by the antenna element 2
Figure BDA0002965426650000064
… … are provided. The field strength generated by the antenna array at the observation point P is therefore:
E＝E0(1+ejφ+ej2φ+ej3φ+…+ej(N-1) φ)
wherein the content of the first and second substances,
Figure BDA0002965426650000071
by using an geometric series summation formula, the above formula is simplified and the absolute value is obtained:
Figure BDA0002965426650000072
f (phi) is an array factor of the N-element uniform linear array; the maximum value can be found by its first derivative being 0, i.e.:
Figure BDA0002965426650000073
the condition obtained is that Φ is 0. The maximum value at this time is N, so the normalized array factor is:
Figure BDA0002965426650000074
substituting the condition phi with the array factor having the maximum value into the formula
Figure BDA0002965426650000075
The following can be obtained:
Figure BDA0002965426650000076
from the above formula, the maximum radiation direction of the antenna array is θmThe phase difference alpha of the current between two adjacent antennas and the distance d. At thetamIn the direction, the phase difference caused by the wave path difference between the radiation fields of the antenna array elements is just offset with the phase difference introduced by the phase shifter, so that the components are added in phase to obtain the maximum value. Obviously, under the condition of a certain d, the radiation direction of the main lobe can be changed by changing the phase difference alpha, so that the electric scanning of the beam is realized.
Referring to fig. 3, based on the above phased array model, electrical scanning of a beam can be achieved, and three specific embodiments are given in the present invention. The invention adopts 8-element uniform linear array, the distance between the antennas is half wavelength, and the radiation direction of the main lobe is changed by changing the feed phase difference alpha to realize the electric scanning of the wave beam from-160 degrees to 160 degrees.
Step 2) using the system to measure the angle of different parts of the body trunk
Based on the phased array system, when the antenna beam is scanned circumferentially or at uniform angular speed within a certain sector range and the amplitude of the echo received by the antenna is maximum, the beam axis direction at the moment is the direction of the target. In the present invention, the equal-signal method is adopted, and the directional diagram thereof refers to fig. 4, that is, two identical beams which are partially overlapped with each other are adopted. Referring to fig. 5(a), if the target is in the direction of the overlap axis OA of the two beams, the two beams receive equal signal strength, otherwise one beam receives a higher signal strength than the other. Therefore OA is called equal signal axis. When the echo signals received by the two wave beams are equal, the direction pointed by the equal signal axis is the direction of the target. Referring to FIG. 5(c) if the object is in the OB direction, the echo of beam 2 is stronger than that of beam 1; referring to fig. 5(b), when the object is in the OC direction, the echo of beam 2 is weaker than that of beam 1. Therefore, the direction of the target deviating from the equal signal axis can be judged by comparing the strength of the two wave beam echoes, and the size of the deviating equal signal axis can be estimated by a table look-up method.
Based on the angle measurement principle of the equal signal method, the invention provides two specific embodiments.
Let the antenna voltage directivity function be F (theta) and the orientation of the equal signal axis OA be theta0Then the directivity functions of beams 1 and 2 can be written as:
F1(θ)＝F(θ1)＝F(θ+θk-θ0) (6)
F2(θ)＝F(θ2)＝F(θ-θk-θ0) (7)
θkis theta0Off angle from the direction of the beam maximum.
Echo signal u received by beam 1, measured by equal signal method1＝KF1(θ)＝KF(θk-θt) Echo voltage value u received by beam 22＝KF2(θ)＝KF(-θk-θt)＝KF(θk+θt) In the formula [ theta ]tDeviation of the equal signal axis theta for the target direction0The angle of (c). Two methods are proposed in the present invention for u1And u2Processing is performed to obtain a target direction thetat。
The first embodiment is amplitude comparison, i.e. the ratio of the two signal amplitudes:
Figure BDA0002965426650000081
the target deviation theta can be judged according to the size of the ratio0By looking up a pre-established table, the target deviation theta can be estimated0The ratio of (a) to (b).
A second embodiment is the sum-difference method, i.e. from u1And u2The difference Delta (theta) can be obtained1) And the sum value sigma (theta)1)：
Δ(θ)＝u1(θ)-u2(θ)＝K[F(θk-θt)-F(θk+θt)] (9)
On the equal signal axis theta ═ theta0In the vicinity, the difference Δ (θ) can be approximately expressed as
Figure BDA0002965426650000091
The sum signal is:
Δ(θ)＝u1(θ)+u2(θ)＝K[F(θk-θt)+F(θk+θt)] (11)
on the equal signal axis theta ═ theta0Nearby, the sum value can be approximately expressed as
∑(θ1)≈2F(θ0)k (12)
The difference and the sum beam Delta (theta) can be obtained by referring to FIG. 61) And sigma (theta)1) Normalized sum and difference value of
Figure BDA0002965426650000092
Since delta/sigma is proportional to the target deviation theta0Angle theta oftSo that it can be used to determine the angle thetatThe size and direction of the light beam.
The embodiment of the present invention can be implemented in two ways. One is to adjust the phase of the antenna array so as to generate two beams simultaneously; the other is that only one of the beams appears at the 1 and 2 positions in time sequence while the beam is scanned electrically
Step 3) using the system to respectively measure the distance of different parts of the trunk
Through the step 1) and the step 2), accurate angle measurement of a plurality of targets is realized, and the targets can be accurately positioned by accurately measuring the distance in the direction of the targets.
In order to effectively position a plurality of trunk parts, the invention adopts a multi-frequency method, an antenna transmits a plurality of signals with different frequencies in different time slots, and the corresponding distance of each signal can be obtained according to the phase lag of each signal generated by the distance. The principle is as follows:
when phase ranging is used, the phase changes by 2 pi when the distance change wavelength is large, assuming that the distance between the target and the transmitter is R and the frequency of the transmitted signal is fiSince the transmitter is located by echo, the distance R can be expressed as:
Figure BDA0002965426650000101
wherein the content of the first and second substances,
Figure BDA0002965426650000102
is a phase lag due to distance, since it is periodic by 2 π
Figure BDA0002965426650000103
May include n 2 pi, and each 2 pi corresponds to a distance:
Figure BDA0002965426650000104
the actual distance is therefore:
Figure BDA0002965426650000105
the maximum unambiguous distance (phase change 2 π) at each frequency is:
Figure BDA0002965426650000106
if the measured distance is greater than the minimum aiPhase ambiguity occurs, making ranging ambiguous. To solve the ambiguity problem, n needs to be solvediThe true value of (d).
From an approximate estimate of the distance, e.g. within 10 meters of indoor range, n can be calculatediMaximum value n ofmax. At not more than niWithin the maximum value range of (2) to niAnd searching is carried out, and meanwhile, the search result is judged by using a least square criterion. When the error is minimum, the real height is obtained.
Step 4) combining the angle information and the distance information to identify the height
The invention provides a Wi-Fi indoor height recognition system based on a phased array principle under an indoor environment, aiming at the condition that the existing indoor sensing technology is lack in height detection. Referring to fig. 7, the invention does not need to train a large amount of data base, only needs to deploy an antenna array in indoor environment, utilizes the thought of phased array to measure the angle, then utilizes a multi-frequency method to measure the distance, combines the angle information and the distance information to detect the height.
Furthermore, the height detection can be completed only by one wireless receiving and transmitting antenna array.
Further, the angle is measured by adopting an equal signal method, and the angle measurement precision is higher than that of a traditional maximum signal method, because when the target is positioned near an equal signal axis, if the target is slightly deviated from the equal signal axis, the intensity of the two signals is obviously changed.
Furthermore, the invention can judge the direction of the target deviating from the equal signal axis according to the strength of the signals received by the two wave beams, thereby being convenient for automatic angle measurement.
Furthermore, the multi-frequency ranging method adopted in the invention solves the problem of phase ambiguity, and can carry out accurate detection by using a single device.

Claims (4)

1. A single-device WiFi indoor height detection method based on a phased array principle is characterized by comprising the following steps:
1) constructing a phased array system: arranging a plurality of antenna units in a straight line to form a uniform linear array, and adding a shifter on each antenna;
2) angle measurements are made for a plurality of targets:
2.1) realizing electric scanning of wave beams, the maximum radiation direction of the antenna array is thetamThe relationship between the current phase difference α and the distance d between the two adjacent antennas is as follows:
Figure FDA0002965426640000011
from the above formula, in θmDirection, between the radiation fields of each antenna array element, the phase difference caused by the wave path difference is just offset with the phase difference introduced by the phase shifter, so that the components are added in phase to obtain the maximum value, obviously, under the condition that d is fixed, the radiation direction of the main lobe can be changed by changing the phase difference alpha, and the electric scanning of the wave beam is realized;
2.2) judging the directions of different parts of the body trunk, and firstly, scanning in coarse granularity;
selecting two middle antennas, adjusting the phases of the antennas by a phased array principle to form a beam to form a scanning system with wider beam, rapidly scanning within a range from-90 degrees to 90 degrees, and determining the approximate range of different parts of the trunk of the body according to echo energy, wherein when the beam points to a target, the echo energy is higher;
2.3) fine-grained scanning, the number of antennas is continuously increased, more and more antennas are used to form a scanning system with narrower beams, and the next scanning is only carried out within the possible range determined by the last antenna array scanning;
2.4) improving the precision, in order to realize higher precision while reducing the number of antennas, adopting an equal-signal method, when scanning with fine granularity, if the echo energies in two directions are approximately the same, indicating that the target is positioned on the angular bisector of the two directions, using all the antennas to form a narrow beam, and determining the direction of the target by using the equal-beam method in the direction determined in the step 2.2);
3) ranging different parts of the body torso: after the directions of the different parts are measured, aiming at each part, ranging is carried out by utilizing a multi-frequency method;
3.1) in different time slots, the antenna transmits radio frequency signals with different frequencies, and phase lag generated by distance under different frequencies can be obtained, wherein the relation between the distance and the phase is as follows:
Figure FDA0002965426640000021
Figure FDA0002965426640000022
is a phase lag due to distance, since it is periodic by 2 π
Figure FDA0002965426640000023
May contain n 2 pi, i.e. there is a phase ambiguity problem, and the distance corresponding to each 2 pi is:
Figure FDA0002965426640000024
3.2) number of phase ambiguities in phase lag niTraversing search is carried out, and n corresponding to the minimum error under the least square criterion is foundiThe phase ambiguity number niRefers to the number of 2 π contained in the actual phase, so the actual distance is:
Figure FDA0002965426640000025
error refers to traversing different n at different frequenciesiThe error of the distance R is calculated, and when the error is minimum, the corresponding group niNamely, the corresponding phase ambiguity numbers under different frequencies are obtained;
3.3) according to niCalculating the true position of different parts of the body torso;
4) multi-target positioning: through step 2) can carry out accurate angle measurement to different parts of the health trunk, through step 3) can carry out accurate distance measurement to every part, combine angle information and distance information, can obtain the position of different parts of trunk.
2. The method for detecting the WiFi indoor height of the single device based on the phased array principle as claimed in claim 1, wherein the phased array principle in the step 2) is that the phase of the antenna is controlled electronically, so that the array antenna can complete beam scanning or rotation in a spatial plane.
3. The method for detecting the indoor height of the single-device WiFi based on the phased array principle as claimed in claim 1, wherein the equal signal method in the step 2.3) is characterized in that two identical beams partially overlapped with each other are adopted, the direction of a target deviating from an equal signal axis is judged by comparing the strength of echoes of the two beams, and then the pointing directions of the beams are adjusted until the strength of the echoes of the two beams is approximately equal, so that the direction of different parts of each trunk of the body is obtained.
4. The method for detecting WiFi indoor height through single device based on phased array principle as claimed in claim 1, wherein in step 3.1), the signals with different frequencies are transmitted in the target direction determined in step 2).
CN202110249544.1A 2021-03-08 2021-03-08 Single-device WiFi indoor height detection method based on phased array principle Pending CN113229802A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110249544.1A CN113229802A (en) 2021-03-08 2021-03-08 Single-device WiFi indoor height detection method based on phased array principle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110249544.1A CN113229802A (en) 2021-03-08 2021-03-08 Single-device WiFi indoor height detection method based on phased array principle

Publications (1)

Publication Number Publication Date
CN113229802A true CN113229802A (en) 2021-08-10

Family

ID=77130409

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110249544.1A Pending CN113229802A (en) 2021-03-08 2021-03-08 Single-device WiFi indoor height detection method based on phased array principle

Country Status (1)

Country Link
CN (1) CN113229802A (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104076357A (en) * 2014-07-07 2014-10-01 武汉拓宝电子***有限公司 Radar device and method used for detecting indoor moving target
CN107883959A (en) * 2017-10-31 2018-04-06 西安交通大学 More people's localization methods in a kind of WiFi rooms based on phased array principle
CN108828576A (en) * 2018-04-10 2018-11-16 上海摩软通讯技术有限公司 Indoor locating system and method
CN208863084U (en) * 2018-08-03 2019-05-14 黄朝一 A kind of outdoor staff positioning device and positioning system
CN111836189A (en) * 2020-06-28 2020-10-27 四川省大见通信技术有限公司 Device and method for positioning interference source

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104076357A (en) * 2014-07-07 2014-10-01 武汉拓宝电子***有限公司 Radar device and method used for detecting indoor moving target
CN107883959A (en) * 2017-10-31 2018-04-06 西安交通大学 More people's localization methods in a kind of WiFi rooms based on phased array principle
CN108828576A (en) * 2018-04-10 2018-11-16 上海摩软通讯技术有限公司 Indoor locating system and method
CN208863084U (en) * 2018-08-03 2019-05-14 黄朝一 A kind of outdoor staff positioning device and positioning system
CN111836189A (en) * 2020-06-28 2020-10-27 四川省大见通信技术有限公司 Device and method for positioning interference source

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEN WANG ET AL.: "Towards In-baggage Suspicious Object Detection Using Commodity WiFi", 《2018 IEEE CONFERENCE ON COMMUNICATIONS AND NETWORK SECURITY (CNS)》 *

Similar Documents

Publication Publication Date Title
CN107883959B (en) WiFi indoor multi-person positioning method based on phased array principle
US5557282A (en) Height finding antenna apparatus and method of operation
EP1910864B1 (en) A system and method for positioning a transponder
US6061022A (en) Azimuth and elevation direction finding system based on hybrid amplitude/phase comparison
US8378885B2 (en) Device and method for locating a mobile approaching a surface reflecting electromagnetic waves
CN109061638B (en) Phased array close-range digital imaging method
Gil-Martínez et al. Direction finding of RFID tags in UHF band using a passive beam-scanning leaky-wave antenna
CN109254173A (en) Multiple target radar meter in-site modeling detection method and detection device
CN111398914B (en) Radar tracking beam angle measurement method
JPS62108175A (en) Radar equipment
CN107390170A (en) The method that three-dimensional fix is carried out based on directional electromagnetic and the anglec of rotation
CN110764059A (en) Three-coordinate phased array radar technology for transmitting and receiving vertical beams
RU2444750C2 (en) Method of determining elevation coordinate of low-flying target
Dumas et al. Self-calibration and antenna grouping for bistatic oceanographic High-Frequency Radars
Hartmann et al. Antenna pattern optimization for a rssi-based direction of arrival localization system
CN113229802A (en) Single-device WiFi indoor height detection method based on phased array principle
RU2593595C1 (en) Method of measuring angular coordinates in nonlinear radar
CN210465677U (en) Rotating field type omnidirectional antenna and omnidirectional detection radar system
RU2729459C1 (en) Method of determining spatial coordinates and speeds of objects using a scanning multiposition radio system
RU2686113C1 (en) Method of amplitude two-dimensional direction-finding
RU2316019C1 (en) Method for measurement of object altitude on the basis of multichannel radar
CN110208754B (en) Rotary field type omni-directional antenna, omni-directional detection radar system and signal processing method
RU2699028C1 (en) Method for direction-finding of a source of active interference
RU2721785C1 (en) Landing radar
JP3015494B2 (en) Monopulse angle measurement radar device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
WD01 Invention patent application deemed withdrawn after publication

Application publication date: 20210810

WD01 Invention patent application deemed withdrawn after publication