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WO2018139771A2 - Procédé et dispositif de positionnement sans fil très précis - Google Patents

Procédé et dispositif de positionnement sans fil très précis Download PDF

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Publication number
WO2018139771A2
WO2018139771A2 PCT/KR2017/015649 KR2017015649W WO2018139771A2 WO 2018139771 A2 WO2018139771 A2 WO 2018139771A2 KR 2017015649 W KR2017015649 W KR 2017015649W WO 2018139771 A2 WO2018139771 A2 WO 2018139771A2
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WIPO (PCT)
Prior art keywords
mobile node
signal strength
pattern
signal
relative position
Prior art date
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Ceased
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PCT/KR2017/015649
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English (en)
Korean (ko)
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WO2018139771A3 (fr
Inventor
이택진
전영민
김재헌
유보선
신범주
방재원
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.)
Korea Institute of Science and Technology KIST
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Korea Institute of Science and Technology KIST
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Filing date
Publication date
Priority claimed from KR1020170121851A external-priority patent/KR101954676B1/ko
Application filed by Korea Institute of Science and Technology KIST filed Critical Korea Institute of Science and Technology KIST
Priority to US16/476,901 priority Critical patent/US10746847B2/en
Priority to EP17893784.3A priority patent/EP3557919B1/fr
Priority to CN201780084270.7A priority patent/CN110463294B/zh
Priority to JP2019539211A priority patent/JP6906617B2/ja
Publication of WO2018139771A2 publication Critical patent/WO2018139771A2/fr
Publication of WO2018139771A3 publication Critical patent/WO2018139771A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
    • H04W64/006—Locating users or terminals or network equipment for network management purposes, e.g. mobility management with additional information processing, e.g. for direction or speed determination
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G01S5/0252—Radio frequency fingerprinting
    • G01S5/02521—Radio frequency fingerprinting using a radio-map
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/18—Service support devices; Network management devices

Definitions

  • a wireless positioning method and apparatus capable of estimating a location of a mobile node using a wireless signal.
  • the Global Navigation Satellite System is a system for estimating the position of moving objects around the earth using radio waves from satellites orbiting space orbits. It is widely used in navigation apparatus of ships, aircrafts, etc.
  • Typical examples of GNSS include Global Positioning System (GPS) in the United States, GLONASS in Russia, Galileo in Europe, and Qasis-Zenith Satellite System (QZSS) in Japan.
  • GPS Global Positioning System
  • QZSS Qasis-Zenith Satellite System
  • GNSS cannot be positioned in an indoor space where radio waves transmitted from satellites cannot reach, and there is a problem in that positioning accuracy is severely degraded in the city center due to radio wave blocking and reflection by high-rise buildings.
  • Wireless communication may be classified into near field communication and wide area communication.
  • Representative examples of short-range wireless communication include Wi-Fi, Bluetooth, and Zigbee.
  • Representative examples of wide area wireless communication include 3G, 3G, and 4G. Etc. can be mentioned.
  • Long Term Evolution (LTE) is a kind of 4G wireless communication. Short-range signals such as Bluetooth and ZigBee are not suitable for positioning because of the temporary occurrence and disappearance of the indoor space according to the user's needs.
  • LTE Long Term Evolution
  • Wi-Fi Wireless Fidelity
  • Typical positioning techniques using Wi-Fi signals include triangulation techniques and fingerprint techniques.
  • the triangulation technique estimates the position by measuring the received signal strength (RSS) of three or more access points (APs) and converting them into distances.
  • RSS received signal strength
  • APs access points
  • the fingerprint technique is mainly used in indoor spaces.
  • This technique divides the interior space into a lattice structure and builds a radio map by collecting and databaseting signal strength values in each unit area. In this way, in the state where the radio map is constructed, the intensity of the signal received at the user's location is compared with the data of the radio map to estimate the user's location.
  • This method has the advantage of very high positioning accuracy compared to triangulation method because it collects data reflecting indoor space characteristics. It is reported that the wireless environment is good and the indoor space is finely divided to collect a lot of signals, and thus the positioning accuracy is improved, which can be improved up to 2-3 meters.
  • the fingerprint technique performs relatively accurate positioning when there is little difference between the signal strength collected at the time of constructing the radio map and the signal strength collected at the time of performing the positioning.
  • changes in the wireless environment such as signal interference between communication channels, expansion of access points, breakdowns or obstacles that occur frequently in the real world lead to the collection of signal strengths that differ from the data of radio maps constructed in the past. This will seriously affect accuracy.
  • various attempts have been made to increase the positioning accuracy by applying K-Nearbor (KNN), particle filter, etc. to the fingerprint technique.
  • the fingerprint technique cannot be used alone in a vehicle navigation system or autonomous driving that requires positioning services for all areas of the outdoors and indoors. It has a natural limitation. LTE signal is distributed evenly throughout the indoor and outdoor, but there is a limit to increase the positioning accuracy due to the large area where the change in signal strength is not large. As a result, the positioning service using LTE signals remains at a level that roughly informs the user's location, and there are still many problems to be used for vehicle navigation systems or autonomous driving where positioning errors can lead to accidents.
  • a high accuracy wireless positioning method and apparatus capable of estimating a position are provided.
  • the present invention provides a computer-readable recording medium having recorded thereon a program for executing the above-described wireless positioning method on a computer.
  • the present invention is not limited to the above-described technical problems, and other technical problems may be derived from the following description.
  • Wireless positioning method comprises the steps of measuring the strength of at least one signal transmitted from at least one fixed node; Estimating the relative position of the mobile node; Generating a change pattern of at least one signal strength according to a relative change in the position of the mobile node over a plurality of time points from the measured at least one signal strength and the relative position of the estimated mobile node; And estimating an absolute position of the mobile node based on a comparison between the generated change pattern of the signal strength and a map in the form of a distribution pattern of signal strength in an area where the mobile node is located.
  • the change pattern of the at least one signal strength is a change pattern of at least one signal strength represented by a continuous sequence of the strengths of at least one signal received a plurality of times at a plurality of relative positions of the mobile node estimated at the plurality of time points.
  • Generating a change pattern of the at least one signal strength generates a pattern of the at least one signal strength currently received from the measured at least one signal strength and the relative position of the estimated mobile node, wherein the generated at least The change pattern of the at least one signal strength may be generated by successively arranging a pattern of one signal to a pattern of at least one signal received before the reception time.
  • the generating of the change pattern of the at least one signal strength may include pattern data representing a pattern of at least one signal strength received from the at least one fixed node at the estimated relative position and the estimated relative position before the relative position estimation.
  • the change pattern of the at least one signal strength may be generated by accumulating the pattern data of the position.
  • the generating of the change pattern of the at least one signal strength may generate the pattern data from spatial domain data representing the measured signal strengths in association with the estimated relative position.
  • the wireless positioning method may further include generating time domain data representing the measured signal strengths in association with one point in time; And converting the generated temporal domain data into the spatial domain data.
  • the one time point may be a reception point of each signal
  • the measured relative position may be a relative position of the mobile node estimated at the reception point of each signal. If the distance difference between the estimated relative position and the relative position of the mobile node estimated immediately before the estimation of the relative position is within a distance corresponding to a resolution unit of coordinates for indicating the relative position of the mobile node, the estimated relative position Accumulation of pattern data representing a pattern of at least one signal strength received from the at least one fixed node may be omitted.
  • the radio location method further includes estimating a relative position of the mobile node relative to the estimated absolute position of the mobile node after estimating the absolute position of the mobile node, and after the plurality of viewpoints, the absolute position of the mobile node.
  • a change pattern of at least one signal strength may be generated according to a relative change in the position of the mobile node from the relative position of the mobile node estimated with respect to the position.
  • the wireless positioning method further comprises the step of searching for a portion having a pattern most similar to the change pattern of the at least one signal strength in the map by comparing the change pattern of the at least one signal strength with the map,
  • the estimating the absolute position of the mobile node may estimate the absolute position of the map indicated by the retrieved portion as the absolute position of the mobile node.
  • the estimating an absolute position of the mobile node may estimate an absolute position corresponding to the estimated relative position among a plurality of absolute positions of the retrieved portion as an absolute position of the mobile node.
  • the generating of the change pattern of the at least one signal strength may include mapping an ID of one fixed node to a first coordinate axis of a multidimensional space, mapping a relative position of the mobile node to a second coordinate axis, and mapping a third coordinate axis to a third coordinate axis.
  • a geometrical graph of a change in at least one signal strength according to a relative change in position of the mobile node in a manner of displaying a dot at a point in a multidimensional space determined by mapping an intensity of a signal transmitted from one of the fixed nodes. It is possible to create a pattern in the form of a surface.
  • the method of wireless positioning further comprises extracting a portion of a surface having a shape most similar to the surface shape in the map by comparing the surface-shaped pattern with the map, and estimating an absolute position of the mobile node. May estimate the absolute position of the map indicated by the retrieved surface portion as the absolute position of the mobile node.
  • the estimating an absolute position of the mobile node may include an absolute position of a portion having a shape most similar to a shape of the estimated relative position among the plurality of absolute positions of the extracted surface portion as the absolute position of the mobile node. It can be estimated.
  • the wireless positioning method may further include selecting at least one cluster among clusters of all regions where a positioning service is provided based on the received at least one signal; And extracting map data representing the map from a radio map in which distribution data of signal strengths of all regions are recorded.
  • a computer-readable recording medium having recorded thereon a program for executing the wireless positioning method on a computer.
  • Wireless positioning device includes a signal processor for measuring the strength of at least one signal transmitted from at least one fixed node; A relative position estimator for estimating a relative position of the mobile node; A pattern generator configured to generate a change pattern of at least one signal strength according to a relative change of the position of the mobile node over a plurality of viewpoints from the measured at least one signal strength and the relative position of the estimated mobile node; And an absolute position estimating unit estimating an absolute position of the mobile node based on a comparison between the generated change pattern of the signal strength and a map in the form of a distribution pattern of signal strength in the region where the mobile node is located. do.
  • the wireless positioning apparatus may further include a sensor unit detecting a movement of the mobile node, and the relative position estimating unit may estimate a relative position of the mobile node from a value of an output signal of the sensor unit.
  • the radio positioning apparatus further includes a buffer for accumulating pattern data generated by the pattern generator, wherein the pattern generator is configured to generate at least one signal strength received from the at least one fixed node at the estimated relative position.
  • the change pattern of the at least one signal strength may be generated by accumulating and storing pattern data representing a pattern in the pattern data stored in the buffer.
  • the conventional radio positioning technique estimates the absolute position of the mobile node using the strength of at least one signal currently received, when a signal strength different from the signal strength collected at the time of constructing the radio map is measured due to a change in radio environment, It is very likely that the current position of the mobile node will be estimated as another adjacent position rather than its actual position.
  • the present invention estimates the absolute position of the mobile node using the change pattern of at least one signal strength according to the relative change of the position of the mobile node over a plurality of viewpoints, the present invention is hardly affected by the change in the wireless environment. Compared with the conventional wireless positioning technology, the positioning error due to the change in the wireless environment is greatly reduced.
  • At least one signal strength according to the relative change in the position of the mobile node over a plurality of time points is obtained. Since the absolute position of the mobile node is estimated using the change pattern, the position of the mobile node can be estimated accurately. Even if there is little change in signal strength between positioning points adjacent to each other on the moving path of the mobile node, within the moving distance corresponding to the length of the change pattern of the signal strength used in the positioning of the present invention, This is because the strength of the LTE signal changes sufficiently to enable accurate position estimation.
  • the position of the mobile node can be accurately estimated by using the LTE signal having little change in signal strength between measurement points on the moving path, it is possible to provide a wireless positioning service that can cover both the indoor and outdoor areas. It can be done. As a result, it is possible to provide a vehicle navigation system capable of both indoor and outdoor positioning or wireless positioning service for autonomous driving, thereby replacing GPS, which is most widely used as a vehicle navigation system but cannot be indoor positioning.
  • the positioning error of the conventional algorithm according to the comparison of the numerical values of the signal strength distributed in the map can be blocked at the source, so that the positioning accuracy of the mobile node can be greatly improved. Since the change in the radio environment at the current position of the mobile node has little effect on the overall shape of the surface, it is currently received when retrieving the portion of the surface that most closely resembles the surface shape of the three-dimensional pattern within the map represented by the map data. Due to the error in signal strength, it is very unlikely that the surface portion that is intended to be extracted will be extracted from another surface portion.
  • FIG. 1 is a block diagram of a wireless communication system according to an embodiment of the present invention.
  • FIG. 2 is a configuration diagram of a radio positioning device of the mobile node 1 shown in FIG. 1.
  • FIG. 3 is a flowchart of a wireless positioning method according to an embodiment of the present invention.
  • FIG. 4 is a view for explaining the principle of pattern formation in step 320 of FIG.
  • FIG. 5 is a diagram illustrating an experimental result of pattern formation in step 320 of FIG. 3.
  • step 320 is a detailed flowchart of step 320 illustrated in FIG. 3.
  • FIG. 7 is a diagram illustrating a three-dimensional spatial coordinate system for generating a change pattern of signal strength used for radio positioning according to the present embodiment.
  • FIG. 8 is a table showing accumulation of pattern data used for wireless positioning according to the present embodiment in a table form.
  • FIG. 9 is a diagram showing an example in which a change pattern of signal strength used for radio positioning according to the present embodiment is generated.
  • 10-11 illustrate examples in which the absolute position of the mobile node 1 is estimated according to the present embodiment.
  • FIG. 13 is a diagram illustrating a comparison experiment result with respect to LTE positioning according to the prior art and the present embodiment.
  • mobile nodes such as a smart phone that is carried by a user and a navigation system that is mounted and moved in a vehicle.
  • mobile nodes such as a smart phone that is carried by a user and a navigation system that is mounted and moved in a vehicle.
  • AP access point
  • base station base station
  • fixed node including a communication device that is fixedly installed in a certain area and relays wireless communication of the mobile node. Let's do it.
  • an RF (Radio Frequency) signal transmitted from the fixed node will be referred to simply as a "signal”.
  • An embodiment of the present invention to be described below relates to a wireless positioning method and apparatus for providing a positioning service using a wireless signal such as a Wi-Fi signal, a Long Term Evolution (LTE) signal, etc.
  • the position of the mobile node can be estimated with high accuracy even when positioning using a wireless signal, for example, an LTE signal, with little change in signal strength over a large area.
  • a high accuracy wireless positioning method and apparatus will be referred to simply as “wireless positioning method” and "wireless positioning device”.
  • the wireless communication system includes a plurality of mobile nodes 1, a plurality of fixed nodes 2, and a positioning server 3.
  • Each of the plurality of mobile nodes 1 performs a wireless communication with another node through at least one kind of wireless communication network while being carried by a user or mounted in a vehicle.
  • each mobile node 1 performs wireless communication through at least two types of wireless communication networks, for example, a Wi-Fi network and an LTE network.
  • Each of the plurality of fixed nodes 2 relays wireless communication of each mobile node 1 so that each mobile node 1 can access a wireless communication network and perform wireless communication with another node.
  • the fixed node may be an access point when the mobile node 1 performs wireless communication through a Wi-Fi network, and the fixed node may be a base station when performing wireless communication through an LTE network.
  • the positioning server 3 provides each mobile node 1 with a portion of the radio map for radio positioning according to the present embodiment.
  • FIG. 2 is a configuration diagram of a radio positioning device of the mobile node 1 shown in FIG. 1.
  • the wireless positioning device of the mobile node 1 illustrated in FIG. 1 includes a wireless communication unit 10, a sensor unit 20, a buffer 30, a scan unit 11, a signal processing unit 12, Relative position estimator 13, domain transformer 14, pattern generator 15, cluster selector 16, map loader 17, comparator 18, and absolute position estimator 19 It is composed.
  • Those skilled in the art to which the present embodiment pertains may implement these components in hardware that provides a specific function, or the software providing the specific function may be implemented in a combination of a memory, a processor, a bus, and the like. It is understood that it may be.
  • Each component described above is not necessarily implemented as separate hardware, and several components may be implemented by a combination of common hardware, for example, a processor, a memory, a bus, and the like.
  • the mobile node 1 may be a smartphone carried by a user or may be a navigation system mounted on a vehicle.
  • the embodiment shown in FIG. 2 relates to a wireless positioning device.
  • the features of the present embodiment may be blurred. It is omitted.
  • Those skilled in the art to which the present embodiment pertains may understand that other components may be added in addition to the components shown in FIG. 2 when the mobile node 1 is implemented as a smartphone or a navigation system. have.
  • the wireless communication unit 10 transmits and receives a signal through at least one wireless communication network.
  • the sensor unit 20 is composed of at least one sensor for detecting the movement of the mobile node (1).
  • the buffer 30 is used for accumulating the pattern data generated by the pattern generator 15.
  • the sensor unit 20 may include an acceleration sensor for measuring the acceleration of the mobile node 1 and a gyro sensor for measuring the angular velocity of the mobile node 1.
  • the sensor type of the sensor unit 20 may vary depending on what kind of device the mobile node 1 is implemented. When the mobile node 1 is implemented as a smartphone, the sensor unit 20 may be composed of an acceleration sensor and a gyro sensor as described above.
  • the sensor unit 20 may be configured with an acceleration sensor and a gyro sensor as described above, and instead of such a sensor, an encoder, a geomagnetic sensor, or the like. May be used.
  • the radio positioning method according to the present embodiment is composed of the following steps executed by the radio positioning apparatus of the mobile node 1 shown in FIG.
  • the scan unit 11, the signal processor 12, the relative position estimator 13, the domain converter 14, the pattern generator 15, and the cluster selector illustrated in FIG. 2 will be described.
  • the map loader 17, the comparison unit 18, and the absolute position estimation unit 19 will be described in detail.
  • the scan unit 11 of the mobile node 1 receives at least one signal transmitted from at least one fixed node 2 by periodically scanning a frequency band of wireless communication through the wireless communication unit 10. .
  • the sampling rate of the time domain data to be described below is determined according to the length of the scan period of the scan unit 11.
  • the accuracy of the absolute position of the mobile node 1 estimated according to the present embodiment can be improved.
  • the scan period of the wireless communication unit 10 is preferably determined. Since the ID transmitted from a fixed node 2 carries the ID of the fixed node 2, the ID of the fixed node 2 can be known from the signal transmitted from the fixed node 2.
  • the wireless communication unit 10 receives one signal from one fixed node 2 through a scanning process. Done. If there are a plurality of fixed nodes 2 within the communicable range at the current position of the mobile node 1, the wireless communication unit 10 may scan the fixed nodes 2 from the plurality of fixed nodes 2 through a scanning process. A plurality of signals as many as) are received. 1 shows an example in which the mobile node 1 receives three signals from three fixed nodes 21, 22, 23. It can be seen that the other fixed node 24 is located outside the communicable range of the mobile node 1.
  • the mobile node 1 Since the present embodiment can be applied to a region where the wireless communication infrastructure is relatively well equipped, the mobile node 1 receives signals from a plurality of fixed nodes 2 mostly, but in some regions where the wireless communication infrastructure is weak, one fixed node is used. The signal of (2) may be received. On the other hand, when no signal is received in the scanning process, since the positioning itself according to the present embodiment is impossible, the mobile node 1 waits until it receives the signal of the fixed node 2.
  • step 120 the signal processor 12 of the mobile node 1 measures the strength of each signal received in step 110.
  • step 130 the signal processor 12 of the mobile node 1 generates time domain data indicating the signal strengths measured in step 120 in association with any one time point.
  • any one time point is used as information for distinguishing a signal received in step 110 from a signal previously received or a signal received thereafter.
  • This time point may be a reception time point of each signal.
  • the reception point of each signal may be a point in time at which the signal processor 12 reads the time of the internal clock of the mobile node 1 at the moment of receiving each signal from the wireless communication unit 10.
  • the signal processing unit 12 of the mobile node 1 may transmit an ID of the fixed node 2 that transmits each signal for each signal received in step 110, a reception time of each signal, and 120.
  • at least one set of signal strength surrounds the intensity of the signals measured in step as a set ⁇ RSS mn, ... ⁇ and generates a time-domain data, including the TD.
  • RSS stands for "Received Signal Strength”
  • TD stands for "Time Domain”
  • "m” in the subscript indicates the sequence number of the ID of the fixed node 2
  • "n" indicates each signal. Indicates the sequence number at the time of reception.
  • the scanning unit 11 scans the surrounding signals three times. If the scan unit 11 receives only one signal transmitted from the fixed node 2 having the second ID during the third signal scan, the time domain data includes only one signal strength set RSS 23 . If the scan unit 11 receives the signal sent from the fixed node 2 having the second ID and the signal sent from the fixed node 2 having the third ID when the third signal is scanned, the time domain data The signal strength sets RSS 23 and RSS 33 will be included.
  • the time domain data may be referred to as data that divides the strength of each signal measured in step 302 into an ID of the fixed node 2 that transmits each signal in the time domain and a reception time of each signal.
  • the reception time points of the plurality of signal strength sets ⁇ RSS mn , ... ⁇ TD included in the time domain data generated in step 130 are all the same. Accordingly, in order to reduce the length of time domain data, a plurality of fixed node IDs and a plurality of signal strengths may be arranged and pasted at one time point for signals collected at the same time point.
  • the time domain data can be represented in various formats in addition to the formats described above.
  • the relative position estimator 13 of the mobile node 1 periodically receives an output signal of the sensor unit 20.
  • the relative position estimating unit 13 of the mobile node 1 calculates the moving distance and the moving direction of the mobile node 1 from the value of the output signal of the sensor unit 20 received in step 210.
  • the relative position estimating unit 13 of the mobile node 1 may move the mobile node 1 to the previous position of the mobile node 1 based on the moving distance and the moving direction of the mobile node 1 calculated in step 220. Estimate the current relative position of the mobile node 1 relative to the previous position of the mobile node 1 by calculating the relative change in the current position of.
  • the previous position of the mobile node 1 becomes the reference point of the cluster to be described below when the radio positioning method according to the present embodiment is first executed, and after the relative position with respect to the reference point is estimated,
  • the estimated relative position is immediately before the relative position to be estimated.
  • the reception time of each signal is replaced with the relative position of the mobile node 1 at the reception time.
  • the government 13 preferably calculates the relative position of the mobile node 1 periodically in synchronization with the scan period of the scan unit 11.
  • the relative position estimating unit 13 may calculate the relative position of the mobile node 1 at a period shorter than the scan period of the scanning unit 11.
  • the mobile node 1 since the sensor type of the sensor unit 20 may vary depending on what kind of device the mobile node 1 is implemented, the mobile node 1 may be used to estimate the relative position of the mobile node 1. Different navigation algorithms may be used depending on the type of device.
  • the relative position estimating unit 13 may estimate the relative position of the mobile node 1 using a PDR (Pedestrian Dead Reckoning) algorithm.
  • the relative position estimating unit 13 calculates the moving distance of the mobile node 1 by integrating the value of the output signal of the acceleration sensor of the sensor unit 20, and the gyro sensor of the sensor unit 20.
  • the moving direction of the mobile node 1 can be calculated by integrating the value of the output signal.
  • the relative position estimating unit 13 can estimate the relative position of the mobile node 1 using a dead reckoning algorithm.
  • the relative position estimating unit 13 may calculate the moving distance and the moving direction of the mobile node 1 by attaching the acceleration sensor and the gyro sensor of the sensor unit 20 to the wheel of the vehicle.
  • the relative position estimating unit 13 When executed again after the radio positioning method shown in FIG. 3 is executed, the relative position estimating unit 13 performs the estimated movement in step 520 after the estimation of the absolute position of the mobile node 1 in step 520, which will be described below.
  • the relative position of the mobile node relative to the absolute position of node 1 is estimated. Therefore, after the change pattern of at least one signal strength is generated according to the relative change of the position of the mobile node 1 over a plurality of viewpoints in operation 320, that is, the absolute position of the mobile node 1 after the plurality of viewpoints.
  • a change pattern of at least one signal strength is generated according to a relative change in the position of the mobile node 1 from the relative position of the mobile node estimated with respect to.
  • the relative position of the mobile node 1 is not continuously estimated based on the previous relative position of the mobile node 1, but when the relative position of the mobile node 1 is replaced with the absolute position, Since it is estimated based on the absolute position, the section to which the relative position estimation of the mobile node 1 is applied becomes very short, so that the absolute position error of the mobile node 1 due to the accumulation of the error of the relative position due to the repetition of the relative position estimation is almost It does not occur.
  • the PDR and DR algorithms for estimating the relative position of the mobile node 1 estimate the relative position of the mobile node 1 through the integration of the output signal value of the sensor, the relative of the mobile node 1 is relative. As the position estimation is repeated, the error of the relative position of the mobile node 1 accumulates. Accordingly, as the interval to which the relative position estimation of the mobile node 1 is applied increases, the error of the relative position of the mobile node 1 increases.
  • the accuracy of positioning according to the present embodiment is much higher than that of a technique incorporating a relative position estimation algorithm such as PDR and DR in a conventional radio positioning technique.
  • the absolute position of the mobile node 1 After the absolute position of the mobile node 1 is estimated according to the present embodiment, the absolute position may be estimated for each relative position of the mobile node 1 estimated later, and then the relative position of the estimated mobile node 1 is estimated. After estimating a plurality of times, one absolute position may be estimated. In the former case, after the absolute position of the mobile node 1 is estimated, the previous position of the mobile node 1 is always the estimated absolute position immediately before the relative position to be estimated currently. In the latter case, the previous position of the mobile node 1 becomes the estimated absolute position immediately after the absolute position of the mobile node 1 is estimated immediately before the relative position to be estimated now, but thereafter the relative number of times as described above. Until the position is estimated, it becomes the relative position estimated immediately before the relative position to be estimated currently.
  • the domain converter 14 of the mobile node 1 associates the time domain data generated in step 130 with each signal strength measured in step 120 to the relative position of the mobile node 1 estimated in step 230. Convert to the spatial domain data shown.
  • the domain conversion unit 14 is fixed by each set RSS mn for each set of at least one signal strength set ⁇ RSS mn , ... ⁇ TD included in the time domain data generated in step 130.
  • the time domain data is fixed by replacing the reception time of each signal among the ID of the node 2, the reception time of each signal, and the strength of each signal with the relative position of the mobile node 1 corresponding to the reception time of each signal.
  • the ID of (2), the relative position of the mobile node 1, and the strength of each signal are converted into at least one signal strength set ⁇ RSS mn , ... ⁇ SD that combines the set into one set.
  • RSS stands for “Received Signal Strength”
  • SD stands for "Space Domain”
  • “m” in the subscript indicates the sequence number of the ID of the fixed node 2
  • “n” indicates each signal.
  • the order of the relative position of the mobile node 1 corresponding to the order of reception time is shown. If the signal reception in step 110 and the signal reception in step 210 are synchronized and executed in almost the same time zone, the relative position of the mobile node 1 corresponding to the reception point of each signal is estimated movement at the reception point of each signal. It may be the relative position of node 1. In this case, the order of the reception timing of each signal is the order of the relative position of the mobile node 1 as it is.
  • the signal strength set RSS 23 included in the spatial domain data indicates the strength of the signal received from the fixed node 2 having the second ID when the relative position estimator 13 estimates the third relative position. .
  • the relative position of the mobile node 1 corresponding to the reception point of each signal is determined from the relative positions of the relative positions estimated at various time points. It may be a relative position estimated at a time point closest to the reception time point.
  • the time domain data is a time-based data that is associated with each signal strength by receiving each signal strength by grouping the ID of the fixed node 2, the reception time of each signal, and the strength of each signal into one set.
  • the spatial domain data indicates the ID of the fixed node 2 included in the temporal domain data, the relative position of the mobile node 1 estimated at the point of time included in the temporal domain data, and the signal strength included in the temporal domain data. By grouping them into a set, they are spatially based data represented by associating each signal strength with a relative position of the mobile node 1.
  • the reception timings of the plurality of signal strength sets ⁇ RSS mn , ... ⁇ TD included in the time domain data generated in step 130 each time the radio positioning method according to the present embodiment is executed are all the same.
  • the relative positions of the plurality of signal strength sets ⁇ RSS mn , ... ⁇ SD included in the spatial domain data converted in step 310 are also the same. Accordingly, in order to reduce the length of the spatial domain data, a plurality of fixed node IDs and a plurality of signal strengths may be arranged and attached to one relative position with respect to signals collected at the same relative position.
  • the spatial domain data can be expressed in various formats in addition to the formats described above.
  • the pattern generation unit 15 of the mobile node 1 may determine the location of the mobile node over a plurality of viewpoints from at least one signal strength measured in step 120 and the relative position of the mobile node 1 estimated in step 230. Generates a change pattern of at least one signal strength according to a relative change of.
  • the pattern generation unit 15 is configured to determine at least one signal strength currently received in step 110 from at least one signal strength measured in step 120 and the relative position of the mobile node 1 estimated in step 230. By generating a pattern and successively listing the currently received pattern of the at least one signal to the pattern of the at least one signal received before the signal reception time in step 110 of the position of the mobile node 1 over a plurality of time points.
  • the wireless positioning method according to the present embodiment is a method for repeatedly estimating its current absolute position in real time when the mobile node 1 moves in a certain path, while the wireless positioning device shown in FIG. The steps shown are repeated continuously.
  • FIG. 4 is a view for explaining the principle of pattern formation in step 320 of FIG.
  • the intensity of the signal transmitted from the fixed node 2 is attenuated approximately in inverse proportion to the square of the distance from the fixed node 2.
  • the mobile node 1 that the user carries receives the signal of intensity as shown in FIG.
  • a user does not always walk at a constant speed and may temporarily stop during walking. While the user is temporarily stopped, as shown in (b) of FIG. 4, even if the radio positioning method shown in FIG. 3 is repeatedly executed several times, the intensity of the signal transmitted from the fixed node 2 is almost the same. Is measured.
  • FIG. 4 shows a view for explaining the principle of pattern formation in step 320 of FIG.
  • the x-axis represents the point in time at which the signal is measured, and the y-axis represents the signal strength.
  • the x axis represents a relative position (RL) of the mobile node 1
  • the y axis represents a signal strength.
  • the intensity of the signal transmitted from the fixed node 2 is measured each time the radio positioning method shown in FIG. 3 is executed, the intensity of the signal transmitted from the fixed node 2 is continuous as shown in FIG. It is not displayed in the form of a conventional curve, and in reality, the dots displayed at the height corresponding to the signal strength are displayed in a continuous form.
  • the reception point of each signal is replaced by the relative position of the mobile node 1 by the domain converter 14, the signal strength generated by the pattern generator 15 as shown in (c) of FIG.
  • the change pattern is represented by a continuous listing of the strengths of the signals received multiple times at a plurality of relative positions of the mobile node 1 estimated at multiple time points.
  • the change pattern of the at least one signal intensity generated by the pattern generator 15 is continuous of the intensity of the at least one signal received a plurality of times at a plurality of relative positions of the mobile node 1 estimated at a plurality of time points. It can be said that the pattern of change in at least one signal strength represented by the sequence.
  • a radio map indicating a pattern of distribution of signal strength collected in all regions where the wireless positioning service according to the present embodiment is provided is stored.
  • the radio map reflects the ID of the fixed node 2 that has transmitted a signal, the absolute position of the point at which the signal is received, and the strength of the signal, for a number of signals collected in all regions where the radio location service is provided. It is represented by a map in the form of a distribution pattern of signal strength.
  • a pattern that can be matched to such a radio map should be generated. Since the positioning of the mobile node 1 is performed without knowing the position of the mobile node 1, the mobile node 1 generates the time domain data indicated by correlating each signal strength with the reception point of each signal, and then The temporal domain data is converted into the spatial domain data indicated by correlating each signal strength with the relative position of the mobile node 1 corresponding to the reception point of each signal. In order to determine the coordinates of the radio map, the area of the real world where the radio location service is provided is divided into a grid structure with a constant grid-to-grid distance.
  • the pattern generated by the pattern generator 15 is preferably the same resolution as the coordinate resolution of the radio map or as low as a multiple ratio.
  • the relative position of the mobile node 1 is estimated.
  • a plurality of dots representing the intensities of the plurality of signals received at the plurality of relative positions of the mobile node 1 may be concentrated. have.
  • the maximum distance between a plurality of dots that are concentrated together is within a distance corresponding to a unit of resolution of a radio map, that is, a unit of resolution of coordinates for indicating a relative position of the mobile node 1
  • the dot is generated as a single dot, the effect of representing one signal strength, resulting in a change pattern of the signal strength.
  • the coordinate resolution unit of the radio map is 1 meter
  • several dots gathered within 1 meter are generated as if the signal intensity change pattern is generated as if the dots represent one signal strength as one dot. Will result.
  • FIG. 5 is a diagram illustrating an experimental result of pattern formation in step 320 of FIG. 3.
  • the experiment shown in FIG. 5 is to help understand the change pattern of the signal intensity generated as the intensity value of the signal actually measured in the time domain of the real world is converted into the spatial domain.
  • the signal intensity change pattern of the present embodiment is not a two-dimensional graph form of FIG. 5, but a three-dimensional graph pattern reflecting the ID of the fixed node 2.
  • the user has roamed the aisle of a building with a smartphone on which an Android application for measuring signal strength of Wi-Fi is installed.
  • One access point was installed in the center of the front wall of the building's back aisle.
  • the user continues to move forward and then turns left, then moves back and forth through the building's back aisle three times and then turns left to move forward. At this time, the user approaches the access point three times and moves away.
  • the x-axis of FIG. 5B represents a time point at which a signal is measured by the Android application. Since the Android operating system is designed to input a Wi-Fi signal to the application every 1.5 seconds, the time resolution on the x-axis of FIG. 5 (b) is displayed as 1.5 seconds. If the wireless positioning method according to the present embodiment is implemented as an Android application, since the Wi-Fi signal may be provided in units of 1.5 seconds, the interval at the time of receiving a signal in step 110 may be up to 1.5 seconds.
  • the y axis of FIG. 5B represents signal strength measured by the Android application. The height of each dot shown in FIG. 5B is the intensity of each signal measured by the Android application.
  • step 320 illustrated in FIG. 3 includes the following steps executed by the pattern generator 15 illustrated in FIG. 3.
  • the pattern generator 15 receives new spatial domain data from the domain converter 14.
  • the pattern generator 15 determines the relative position of the mobile node 1 indicated by the spatial domain data received in step 321, that is, the relative position estimated in step 230 and the estimated mobile node immediately before the estimation of the relative position ( Check whether the distance difference between the relative positions in 1) is within the distance corresponding to the resolution unit of the coordinate to indicate the relative position.
  • step 322 if the distance difference between the current relative position of the mobile node 1 and the previous relative position is within the distance corresponding to the resolution unit of the coordinates, the process returns to step 321 and waits until new spatial domain data is received again. Otherwise, go to step 323.
  • the distance difference between the relative position estimated in step 230 and the relative position of the mobile node 1 estimated immediately before the estimation of the relative position corresponds to a resolution unit of coordinates for indicating the relative position of the mobile node 1. If it is within the distance to generate and accumulate the pattern data in steps 323 and 324 to be described below can be omitted.
  • the wireless positioning method shown in FIG. 3 is repeatedly executed, the relative position of the mobile node 1 is measured a plurality of times, and the maximum distance between the plurality of relative positions corresponds to the resolution unit of the coordinate. Even if the signal strengths of the plurality of relative positions are reflected in the pattern generation process in the pattern generator 15 when the distance is within the distance, the signal strength is generated as if the signal strength is represented as one relative position. This results in a change pattern of.
  • step 321 the process proceeds directly from step 321 to step 323 without going through step 322, the accuracy of positioning according to the present embodiment is not affected.
  • the signal strength is repeatedly displayed at various positions within a distance corresponding to the resolution unit of the coordinates, the repetition of the signal strength generated by the pattern generator 15 has little effect on the shape of the change pattern. Since the display process of the signal strength may increase the graphic data throughput of the mobile node 1, it may affect the real-time performance of the radio positioning. Omission of generation and accumulation of pattern data may be useful.
  • the pattern generator 15 may determine the at least one signal strength received from the at least one fixed node 2 at the relative position of the mobile node 1 estimated in step 230 from the spatial domain data received in step 310. Create a pattern.
  • the pattern of the at least one signal strength generated by the pattern generator 15 in step 323 is at least one fixed node indicated by the spatial domain data at a relative position indicated by the spatial domain data in the movement path of the mobile node 1. Is a pattern of at least one signal strength generated by indicating at least one signal strength represented by the spatial domain data.
  • the pattern generator 15 has at least one signal strength set ⁇ RSS mn, ... ⁇ , each signal strength of the set SD included in the spatial domain data received in step 310 RSS mn At least one signal strength pattern is generated by generating a signal strength graph representing the signal strength of each signal strength set RSS mn .
  • FIG. 7 is a diagram illustrating a three-dimensional spatial coordinate system for generating a change pattern of signal strength used for radio positioning according to the present embodiment.
  • the x-axis of the three-dimensional space is a coordinate axis that lists the IDs of the plurality of fixed nodes 2 at regular intervals, and the y-axis indicates a relative position of the mobile node 1 as a moving path of the mobile node 1.
  • the coordinate axis divided by the resolution unit of the coordinates to be produced, and the z axis is the coordinate axis obtained by dividing the measurement range of the intensity of the signals received from the plurality of fixed nodes 2 by the measurement resolution unit of the signal intensity.
  • the information represented by the x-axis, the y-axis, and the z-axis of the three-dimensional space can be interchanged with each other.
  • the x axis may represent the relative position of the mobile node 1 and the y axis may represent the ID of the fixed node 2.
  • the three-dimensional spatial coordinate system shown in FIG. 7 is based on the assumption that a moving path of a user or a vehicle is determined, such as a road in a city, and a radio map stored in a database of the positioning server 3 moves along the determined path.
  • the distribution pattern of the signal strength of the radio map which will be described below, includes a moving path. That is, when the change pattern of the current signal strength of the mobile node 1 coincides with a part of the radio map, the comparison with the radio map indicates that the mobile node 1 is located at a certain point of a certain moving path. Can be.
  • step 110 If the movement path of the mobile node 1 is not determined or if the height of the mobile node 1 is to be estimated in addition to the position of the mobile node 1 on the ground, at least one received in step 110 in a multidimensional spatial coordinate system of four or more dimensions A pattern of variation in the strength of the signal may need to be generated.
  • 10 access points corresponding to the fixed node 2 of the Wi-Fi network are listed on the x-axis of FIG. 7, and a user carrying the mobile node 1 is shown on the y-axis. They are listed at 10 meter intervals in metric intervals. Therefore, the resolution unit of the relative position coordinate of the mobile node 1 is 1 meter.
  • the change pattern of the signal strength compared with the map represented by the map data in step 510 is a three-dimensional pattern generated in the three-dimensional space of the size shown in FIG. That is, the size of the three-dimensional space shown in Fig.
  • step 323 is a change in signal strength compared with the map represented by the map data at intervals of 10 meters with respect to the path traveled by the mobile node 1 during the positioning according to the present embodiment. This means that the pattern is created. At this time, the number of access points on the movement path of the mobile node 1 is ten.
  • the three-dimensional spatial coordinate system shown in FIG. 7 is only an example, and the number of access points and the length of the moving path of the mobile node 1 may be variously modified.
  • the step 323 may be divided into the following steps 3231 and 3232. Hereinafter, the pattern formation process in step 323 will be described in detail with reference to FIG. 7.
  • the pattern generator 15 maps the ID of the fixed node indicated by any one signal strength set RSS mn included in the spatial domain data received in step 321 to the x-axis of the three-dimensional space, set signal strength in such a way that RSS mn to map the relative location of the mobile node 1 shown, and displays a dot at the point of the three-dimensional space is determined by mapping the intensity of the signal strength set signal indicative of the RSS mn in the z-axis
  • a graph representing the signal strength of the signal strength set RSS mn is generated.
  • the signal strength graph is not an output graph for showing to the user, but a graphic element of an intermediate stage for showing a process of generating a change pattern of signal strength in the form of a 3D graph used for wireless positioning.
  • a signal strength graph for each signal strength set RSS mn a pattern of signal strength at one relative position, and a pattern of change of signal strength according to relative position change may be visually recognized. It is assumed that it is in the form of the present invention.
  • step 3232 the pattern generator 15 checks whether the signal strength graph generation in step 3231 is completed for all signal strength sets RSS mn included in the spatial domain data received in step 321. As a result of checking in step 3232, when the signal strength graph generation for all the signal strength set RSS mn is completed, it is determined that the pattern generation for the received spatial domain data is completed in step 321, and the process proceeds to step 324; extracting the other of the set of signal strength RSS mn that is not yet performed in a signal strength graph generated RSS mn plurality of sets of signal strength with and returns to step 3231.
  • the pattern of the at least one signal strength generated by the pattern generator 15 is associated with the ID of at least one fixed node indicated by the spatial domain data and the relative position indicated by the spatial domain data, and thus the spatial domain data.
  • the pattern generator 15 accumulates and stores pattern data representing the pattern of at least one signal strength generated in operation 313, in the pattern data stored in the buffer 30. By accumulating the pattern data, a change pattern of at least one signal strength measured in step 120 is generated.
  • the buffer 30 may accumulate as much pattern data as is necessary for generating a change pattern of signal strength compared to a map represented by map data, and a larger amount of pattern data may be accumulated. In the latter case, a change pattern of signal strength is generated from a part of the pattern data accumulated in the buffer 30.
  • FIG. 8 is a table showing accumulation of pattern data used for wireless positioning according to the present embodiment in a table form.
  • the pattern data accumulated in the buffer 30 is represented in a table form.
  • the pattern generator 15 may accumulate the spatial domain data in the buffer 30 in the form of a table of FIG. 8A.
  • the value of "m" of "APm” corresponds to the ID of the fixed node 2 and corresponds to the coordinate value of the x-axis of the three-dimensional space, and the value of "n" of "RLn” moves.
  • the order of the relative position of the node 1 corresponds to the coordinate value of the y-axis in the three-dimensional space, and "RSS mn " is sent out from the fixed node 2 having the ID of "APm” and the relative position of the mobile node 1. It is the intensity of the signal received at "RLn” and corresponds to the coordinate value of the z-axis in three-dimensional space.
  • the "RSS mn " on any one point of the two-dimensional plane determined by the "m” value of "APm” and “n” value of "RLn” since the dots are displayed at a height corresponding to a value set of "RSS mn” shown in (a) of Figure 8 is to form a geometric surface (surface) in the three-dimensional space.
  • the pattern generator 15 maps the ID of one fixed node to the x-axis of the three-dimensional space, maps the relative position of the mobile node 1 to the y-axis, and maps the relative position of the mobile node 1 to the z-axis.
  • the plurality of signal strength sets included in the spatial domain data accumulated in the buffer 30 may not be accumulated in the buffer 30 in the form of a table of FIG. 8 (a), and may be in various forms for efficient use of the memory space. May accumulate in the buffer 30.
  • FIG. 9 is a diagram showing an example in which a change pattern of signal strength used for radio positioning according to the present embodiment is generated.
  • the relative position of the mobile node 1 is estimated twenty times and a three-dimensional pattern in the form of a surface is generated by the pattern at each of the twenty relative positions.
  • the surface shown in FIG. 9 is formed by dense dots of different heights.
  • Curvature of the surface is represented by the difference between the "RSS mn" in intensity by the difference between, that are adjacent to each other signals sent from the fixing node (2) which are adjacent to each other.
  • the cluster selecting unit 16 of the mobile node 1 selects at least one cluster from clusters of all regions where the positioning service according to the present embodiment is provided based on at least one signal received in step 110. do.
  • the whole area where the radio location service is provided is divided into a plurality of clusters.
  • the cluster selecting unit 16 selects one cluster in which the mobile node 1 is located based on the ID of the at least one fixed node 2 included in the at least one signal received in step 110. do. For example, if a fixed node 2 transmits a signal only to a specific cluster, or if a combination of multiple fixed nodes 2 can receive a signal only from a specific cluster, the cluster may only be identified by the ID of at least one fixed node 2. Can be selected.
  • the cluster selecting unit 16 determines the strength of the at least one signal received in step 110. Based on this, one cluster in which the mobile node 1 is located is selected. For example, if a fixed node 2 sends signals to two neighboring clusters, or if a combination of signals from a plurality of fixed nodes 2 is possible in two neighboring clusters, at least one signal may be used. The cluster may be selected based on the intensity. The cluster selecting unit 16 may select a plurality of clusters by adding a cluster around the cluster to the selected cluster. For example, a plurality of clusters may be selected when the mobile node 1 is located at the boundary between two neighboring clusters or when the number of clusters is increased to improve the accuracy of radio positioning.
  • step 420 the map loader 17 of the mobile node 1 requests to transmit the map data corresponding to the at least one cluster selected in step 310 to the positioning server 3 through the wireless communication unit 10. Send it.
  • data representing at least one cluster selected in step 410 is carried.
  • step 430 when the positioning server 3 receives the request signal for the map data transmitted from the mobile node 1, the radio map in which distribution data of signal strengths in all regions where the positioning service according to the present embodiment is provided is recorded. Map data representing a map in the form of a distribution pattern of signal strength in at least one cluster represented by the request signal, that is, at least one cluster selected in step 410, is extracted. The radio map is stored in the database of the positioning server 3.
  • the positioning server 3 transmits the map data extracted in step 430 to the mobile node 1.
  • the mobile node 1 receives map data transmitted from the positioning server 3.
  • the mobile node 1 can receive map data as shown in FIG. 8 (b).
  • the "m" value of "APm” is the sequence number of the ID of the fixed node 2 installed in the region of the at least one cluster selected in step 410, and the "n" value of "ALn”.
  • As the sequence number of the absolute position (AL, Absolute Location) of the mobile node 1 "RSS mn " is sent from the fixed node (2) having the ID of "APm", the absolute position "ALn” of the mobile node (1) The strength of the signal received at.
  • the format of the map data is the same as that of the pattern data. Therefore, the description of the map data will be replaced with the description of the pattern data described above. Since the map data is extracted from a radio map constructed by constructing a database of numerous signal strengths collected in an area where a radio location service is provided, the value of "RSS mn " of FIG. 8B is represented as a specific value. If the mobile node 1 has enough databases to accommodate the radiomaps stored in the database of the positioning server 3, the mobile node 1 will extract map data from the radiomaps stored in its internal database. It may be. In this case, steps 420, 440, and 450 may be omitted, and step 430 may be performed by the mobile node 1.
  • the comparator 18 of the mobile node 1 includes a map represented by the change pattern of at least one signal intensity generated in operation 320 and map data received in operation 450, that is, an area in which the mobile node 1 is located.
  • map data received in operation 450
  • the comparator 18 compares a three-dimensional pattern of a geometric surface form graphing a change in at least one signal intensity generated in step 320 with a map represented by map data received in step 450.
  • the surface portion having the shape most similar to the surface shape of the three-dimensional pattern graphized by the change in the signal strength generated in step 320 is searched for.
  • the present embodiment is generated in step 320 based on the surface correlation between the change pattern of at least one signal strength generated in step 320 and the distribution pattern of signal strength represented by the map data received in step 450.
  • the change pattern of the at least one signal strength is determined where it is located in the map represented by the map data received in step 450.
  • surface correlation may be calculated using a three-dimensional shape matching algorithm that is well known to those skilled in the art.
  • the absolute position estimating unit 19 of the mobile node 1 determines the absolute position of the map indicated by the portion extracted by the comparison in step 510, and more particularly, the surface portion that has been extracted. Estimate with absolute position.
  • the present embodiment uses the change pattern of at least one signal strength according to the relative change of the position of the mobile node 1 over a plurality of viewpoints up to now without considering only the currently received signal strength. Since the position of the mobile node 1 is estimated, if the length of the change pattern of the signal strength is set very long, the real-time of positioning of the mobile node 1 may be deteriorated. However, the shape similarity between the surface representing the signal intensity change pattern up to the current position of the mobile node 1 and the surface representing the distribution pattern of the signal intensity represented by the map data can be rapidly changed using a three-dimensional shape matching algorithm. Since it can be determined, even if the length of the change pattern of the signal strength over a plurality of time points is very long, the real-time property of the positioning of the mobile node 1 can be ensured.
  • FIGS. 10-11 illustrate examples in which the absolute position of the mobile node 1 is estimated according to the present embodiment.
  • the scale of the three-dimensional space coordinate system shown in FIGS. 10-11 is the same as the scale of the three-dimensional space coordinate system shown in FIG. 7, and the example of the pattern based on the relative position of the mobile node 1 shown on the left side of FIGS. 10-11. Is the same as the example shown in FIG.
  • the example of the absolute position-based pattern of the map shown on the right side of Figs. 10-11 shows a map of the distribution pattern of the signal strength for the travel path up to 100 meters.
  • the map indicated by the map data provided by the positioning server 3 is much larger than the map shown on the right side of Figs. 10-11, but the map data indicated on the right side of Figs. Only parts related to matching with the pattern shown on the left side of 10-11 are shown.
  • a three-dimensional pattern in the form of a surface shown on the left side of FIG. 10A is generated.
  • the comparator 18 searches for the darkly displayed portion in the pattern map shown on the right side of FIG. Similarly, when the user moves 40 meters, 60 meters, and 80 meters, three-dimensional patterns in the form of surfaces shown in the left side of FIGS. 10-11 (b), (c), and (d) are sequentially generated.
  • the comparator 18 searches for the areas marked in bold in the pattern map shown on the right side of FIGS. 10-11 (b), (c) and (d).
  • the absolute position estimating unit 19 moves the absolute position corresponding to the relative position estimated in step 230, that is, the last estimated relative position, from among the plurality of absolute positions of the portion extracted in step 510, that is, the surface portion. Estimate the absolute position of.
  • the absolute position estimating unit 19 determines the absolute position of the mobile node 1 from the absolute position of the portion having the shape most similar to the shape of the relative position estimated in step 230 among the plurality of absolute positions of the surface portion extracted in step 510. Estimate by location.
  • FIG. 12 is a view showing a comparison experiment results for the Wi-Fi positioning according to the prior art and this embodiment.
  • KNN K-Nearest Neighbor
  • Particle Filter algorithm Particle Filter and PDR fusion algorithm, which are well known in the conventional wireless positioning technology
  • SC Surface Correlation
  • the positioning error of the KNN algorithm is indicated by a solid line
  • the positioning error of the particle filter algorithm is indicated by a dashed-dotted line
  • the dotted line of the fusion algorithm of the particle filter and the PDR the positioning error of the present embodiment is represented by It is indicated by a dotted line.
  • the positioning error of the fusion algorithm of the particle filter and the PDR is relatively lower than other positioning algorithms
  • the positioning error according to the present embodiment is maintained at a very low level compared to the conventional positioning algorithm. Can be.
  • the average value and the maximum value of the positioning error are much lower than those of the conventional positioning algorithm.
  • radio location algorithms including the KNN algorithm, particle filter algorithms, and the fusion algorithm of particle filters and PDR, commonly estimate the position of the mobile node 1 using only the currently received signal strength. If signal strengths differ from those collected at the time of radio map construction due to changes in the wireless environment, such as signal interference between communication channels, expansion of access points, breakdowns or obstructions, etc., adjacent points within the radio map are similar. Because of the signal strength distribution, the conventional radiolocation algorithm has a very high probability of estimating the current position of the mobile node 1 as another adjacent position rather than its actual position. The greater the difference between the signal strength collected at the time of radio map construction and the strength of the currently received signal, the greater the positioning error.
  • the present embodiment estimates the position of the mobile node 1 using a change pattern of at least one signal strength according to the relative change of the position of the mobile node over a plurality of viewpoints, so that signal interference between communication channels is estimated.
  • a change in the wireless environment such as an expansion of an access point, a failure or an obstacle occurs
  • an error of an estimated value of the current position of the mobile node 1 hardly occurs. That is, the present embodiment considers not only the strength of the currently received signal but also all the past signal strengths received in the path that the mobile node 1 has passed so far, based on the change pattern of the signal strength of the mobile node 1. Because of estimating the current position of, the change in the radio environment at the current position of the mobile node 1 has little effect on the estimation of the current position of the mobile node 1.
  • the adjacent point of the actual position of the mobile node 1 is a point that deviates from the path indicated by the change pattern of the signal strength so far. do.
  • the change in the radio environment at the point where the mobile node 1 is currently located cannot change the whole change pattern of the signal strength received in the path that the mobile node 1 has passed so far. Since only the current view portion is changed, when the position of the mobile node 1 is estimated using a change pattern of at least one signal strength according to the relative change of the position of the mobile node over a plurality of views up to now, the conventional radio positioning is performed.
  • the intensity of the signal received from a fixed node 2 forms a peak as it passes around, and this peak tends not to be significantly affected by changes in the radio environment. Therefore, the mobile node 1 has already passed the length of the change pattern of the signal strength used for positioning according to the present embodiment even if the signal currently received is not a peak or an adjacent portion of the peak, to the extent that the real time of the positioning is guaranteed. Making it long enough to cover the peaks of the various signals on the on-path makes it very robust to changes in the wireless environment.
  • the position change between the peak and the peak in the change pattern of the signal strength used for positioning according to the present embodiment is estimated relative position of the mobile node 1 within a relatively short distance without error accumulation according to the relative position estimation. Since it can be accurately estimated by, the accuracy of the position estimation of the mobile node 1 can be greatly improved even when the radio environment changes severely.
  • the change pattern of the signal strength used for positioning is a three-dimensional geometric surface form graphing the change of the at least one signal strength according to the relative change of the position of the mobile node 1.
  • the change in the radio environment at the current position of the mobile node 1 is the strength of the currently received signal. This only leads to a height error of the surface portion corresponding to, and does not affect most of the surface at points other than the point of change of the wireless environment. In other words, changes in the radio environment at the current position of the mobile node 1 have little effect on the overall shape of the surface, even if it results in some deformation of the surface shape.
  • the conventional radio location algorithm compares the numerical value of the currently received signal strength with the numerical value of the signal strength distributed in the radio map, so that the mobile node 1 has the numerical value most similar to the numerical value of the currently received signal strength. The result is that the adjacent point of the actual position is incorrectly estimated as the position of the mobile node 1.
  • the change in the radio environment at the current position of the mobile node 1 has little effect on the overall shape of the surface, it has the shape most similar to the surface shape of the three-dimensional pattern in the map represented by the map data.
  • the positioning error of the conventional algorithm according to the comparison between the numerical value of the signal strength currently received and the signal value distributed in the radio map may be blocked at the source, thereby greatly improving the positioning accuracy of the mobile node 1. Can be.
  • FIG. 13 is a diagram illustrating a comparison experiment result with respect to LTE positioning according to the prior art and the present embodiment.
  • the LTE signal was carried using the LTE signal while carrying out the surface correlation based wireless positioning algorithm and the KNN algorithm according to the present embodiment.
  • FIG. 13A illustrates a moving path estimated by the surface correlation-based wireless positioning algorithm according to the present embodiment with respect to the actual moving path “LTE database” of the mobile node 1, and a moving path estimated by the KNN algorithm.
  • the movement path estimated by GPS is shown.
  • FIG. 13 (b) shows the position and actual position of the mobile node 1 estimated by the KNN algorithm and the surface correlation based wireless positioning algorithm according to the present embodiment among the methods shown in FIG. 16 (a). The error of is shown.
  • the position of the mobile node 1 estimated by the surface correlation-based wireless positioning algorithm according to the present embodiment is indicated by a circle, and the position of the mobile node 1 estimated by the KNN algorithm is shown.
  • the position is indicated by a rectangle, and the position of the mobile node 1 estimated by GPS is indicated by a triangle.
  • the surface correlation based wireless positioning algorithm according to the present embodiment can be seen that the position of the mobile node 1 is accurately estimated along the actual moving path of the mobile node 1.
  • the surface correlation-based wireless positioning algorithm according to the present embodiment accurately estimates the position of the mobile node 1 rather than GPS, which is known to have the best positioning accuracy.
  • the positioning error of the surface correlation-based wireless positioning algorithm according to the present embodiment is indicated by black dots, and the positioning error of the KNN algorithm is indicated by a rectangle.
  • the positioning error according to the present embodiment is maintained at a very low level compared to the conventional positioning algorithm.
  • the conventional radio positioning algorithm commonly estimates the position of the mobile node 1 using only the currently received signal strength, so that the change in signal strength between positioning points on the moving path of the mobile node 1 is reduced. In rare cases, the signal strength alone cannot distinguish the location points, and is very sensitive to ambient noise, resulting in very large positioning errors. As shown in (a) of FIG. 13, the position of the mobile node 1 estimated by the conventional radio positioning algorithm is caused to bounce off the actual moving path of the mobile node 1.
  • the present embodiment can accurately estimate the position of the mobile node 1 by using the LTE signal having little change in signal strength between measurement points on the moving path, thereby covering both the indoor and outdoor areas. It may be possible to provide a radio location service.
  • the present embodiment uses the LTE signal widely distributed throughout the building and the city center, and enables the vehicle navigation system or the autonomous driving for the autonomous driving, which can perform both indoor and outdoor positioning with high accuracy even in the city without the influence of high-rise buildings. It can be used as a vehicle navigation system, but it can replace GPS, which cannot be used indoor positioning and severely degrades the positioning accuracy in the city.
  • positioning according to the present embodiment may be performed using the strength of a wireless signal such as Bluetooth, Zigbee, Laura, or the like.
  • the wireless positioning method according to an embodiment of the present invention as described above can be written in a program executable in a processor of a computer, it can be implemented in a computer that writes the program to a computer-readable recording medium to execute have.
  • Computers include all types of computers capable of executing programs, such as desktop computers, notebook computers, smart phones, and embedded type computers.
  • the structure of the data used in the above-described embodiment of the present invention can be recorded on the computer-readable recording medium through various means.
  • the computer-readable recording medium may be a storage medium such as a RAM, a ROM, a magnetic storage medium (for example, a floppy disk, a hard disk, etc.), an optical reading medium (for example, a CD-ROM, DVD, etc.).

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

La présente invention concerne un procédé et un dispositif de positionnement sans fil très précis tels que : l'intensité d'au moins un signal émis à partir d'au moins un nœud fixe est mesurée ; la position relative d'un nœud mobile est estimée ; un motif de variation d'au moins une intensité de signal en fonction du changement relatif de positon du nœud mobile sur de multiples points temporels est généré à partir de ladite intensité de signal et de la position relative du nœud mobile ; et la position absolue du nœud mobile est estimée sur la base d'une comparaison entre le motif de variation de ladite intensité de signal et une carte d'un motif de répartition d'intensité de signal au niveau d'une zone dans laquelle est positionné le nœud mobile. Ainsi, la position du nœud mobile peut être estimée avec précision même lorsqu'un environnement sans fil change, et la position du nœud mobile peut être estimée avec précision sur une large zone en utilisant un signal sans fil ne présentant presque aucun changement d'intensité du signal.
PCT/KR2017/015649 2017-01-25 2017-12-28 Procédé et dispositif de positionnement sans fil très précis Ceased WO2018139771A2 (fr)

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US16/476,901 US10746847B2 (en) 2017-01-25 2017-12-28 Method and apparatus for wireless localization of high accuracy
EP17893784.3A EP3557919B1 (fr) 2017-01-25 2017-12-28 Procédé et dispositif de positionnement sans fil très précis
CN201780084270.7A CN110463294B (zh) 2017-01-25 2017-12-28 高准确度的无线定位方法及装置
JP2019539211A JP6906617B2 (ja) 2017-01-25 2017-12-28 高正確度の無線測位方法及び装置

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KR10-2017-0011988 2017-01-25
KR1020170121851A KR101954676B1 (ko) 2017-01-25 2017-09-21 고정확도의 무선 측위 방법 및 장치
KR10-2017-0121851 2017-09-21

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CN111800853A (zh) * 2020-05-22 2020-10-20 宁波大学 基于信号rssi的设备群体定位方法
JP2021101524A (ja) * 2019-12-24 2021-07-08 日本電気株式会社 自律走行装置、電界強度情報収集システム、電界強度測定方法、及び、電界強度測定プログラム
CN116134860A (zh) * 2020-07-27 2023-05-16 大金工业株式会社 推定系统以及推定方法

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KR101028964B1 (ko) * 2008-11-28 2011-04-12 경희대학교 산학협력단 무선 센서 네트워크에서 선택 파라미터에 기반하여 선택된 송신 센서 노드를 통해 데이터를 송신하는 방법
KR101178042B1 (ko) * 2010-07-21 2012-08-30 한국과학기술원 실내 내비게이션을 수행하는 위치 기반 서비스 시스템 및 방법
KR101260647B1 (ko) * 2011-08-19 2013-05-06 서울대학교산학협력단 무선센서네트워크 상에서 효율적인 다변측량을 이용한 무선측위방법과 이를 실시하기 위한 프로그램이 기록된 기록매체
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KR101634126B1 (ko) * 2014-09-23 2016-06-29 주식회사 아이티원 위치 추정 방법, 장치 및 그 기록매체

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Publication number Priority date Publication date Assignee Title
JP2021101524A (ja) * 2019-12-24 2021-07-08 日本電気株式会社 自律走行装置、電界強度情報収集システム、電界強度測定方法、及び、電界強度測定プログラム
JP7351216B2 (ja) 2019-12-24 2023-09-27 日本電気株式会社 自律走行装置、電界強度情報収集システム、電界強度測定方法、及び、電界強度測定プログラム
CN111800853A (zh) * 2020-05-22 2020-10-20 宁波大学 基于信号rssi的设备群体定位方法
CN116134860A (zh) * 2020-07-27 2023-05-16 大金工业株式会社 推定系统以及推定方法

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