JP2005109700A - Method and device for detecting position of indoor moving object by radio lan system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of detecting the position of an indoor moving object by a radio LAN system, in which a device is simplified itself regardless of a wide indoor space and the position of the indoor moving object can be detected more accurately while hardly affected by a multipath indoors. <P>SOLUTION: The method has high frequency antennas 1a to 1h connected to a radio LAN base station device 11 independently of one another and radio LAN slave units 8a provided in indoor moving objects, and the high frequency antennas 1a to 1h have antenna elements 6a and 6b having directivity and are arranged like a grid in an indoor space 14 and have communication areas 15a to 15d and 16a to 16d which are parallel with high frequency antennas 1a to 1h and have a certain width. The position of a specific indoor moving object is determined by a communication condition between the radio LAM slave unit 9a of the specific indoor moving object and two mutually crossing high frequency antennas 1g and 1b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for detecting the position of a moving object indoors using a wireless LAN system.

  In general, there is a GPS (Global Positioning System) as a system that provides location information of a portable terminal or a mobile terminal outdoors. This GPS receives the radio wave from the satellite and processes it to grasp the current location of the terminal.

  However, GPS cannot be used indoors because radio waves from satellites cannot be received or are difficult to receive. Examples of such indoors include offices such as buildings, buildings such as factories, warehouses, and hospitals, indoors in ordinary houses and offices, large temporary structures such as tents, event venues, and indoors of exhibition halls. Is done.

  On the other hand, a position detecting device using a wireless LAN system (intra-area wireless communication network) has been proposed for detecting the position of a moving object such as a forklift indoor (see Patent Document 1).

This position detection device has a plurality of high-frequency antennas connected to a communication modem, which is a wireless LAN base station device, on an indoor ceiling such as a warehouse. They are spaced apart from each other so as to cover the entire indoor area. Then, the on-board unit (wireless LAN slave unit) mounted on the forklift and the wireless LAN base station apparatus communicate with each other via each high-frequency antenna, and the on-vehicle unit at each arranged high-frequency antenna Compare radio field strength of radio signals from the aircraft. Further, the position of the forklift is detected by determining which high-frequency antenna the forklift is close to based on the comparison result of the radio field intensity at each high-frequency antenna.
Japanese Patent Laid-Open No. 7-15848 (Pages 1 and 2, Fig. 1)

  Here, the wireless LAN system uses a wide frequency band (hereinafter referred to as radio waves, electromagnetic waves) between a wireless LAN base station device (master unit) and a large number of wireless LAN slave units installed indoors (in the area). Communication), and forms a wireless communication network indoors (in the area). For this communication, a high-frequency antenna connected to the wireless LAN base station device is required. A high-frequency waveguide (high-frequency line) constituting the high-frequency antenna and an antenna element arranged on the high-frequency line are indispensable. This high-frequency line is simple and does not take up much space other than a waveguide made of a conductive metal such as stainless steel, steel, copper, or aluminum, or a microwave transmission line other than a waveguide such as a coaxial cable. A strip-shaped high-frequency line (high-frequency microstrip line) that can be installed is used.

  The point of the position detection device for a moving body described in Patent Document 1 is to compare the radio field intensity of a radio signal from an onboard unit (wireless LAN slave unit) at each high-frequency antenna placed on the ceiling of a warehouse. .

  However, although this is a problem specific to indoor wireless LAN systems, wireless signals from onboard units are inevitably located near forklifts in addition to direct waves received by each high-frequency antenna connected to the wireless LAN base station. Reflected waves (multipath) are easily generated by existing objects such as walls and shelves. For this reason, the received wave at each high-frequency antenna tends to be a combined wave of a direct wave from the onboard unit and a plurality of reflected waves. When there are many such reflected waves, the radio field intensity of the high frequency antenna closest to the onboard unit is not always the highest. For this reason, as long as there are many such reflected waves, there is a drawback that an error is likely to occur in the position detection of the moving body.

  In particular, assuming a large building area such as a factory or warehouse, there are many metal structures (ceilings, walls, columns, equipment, machines, etc.) that easily reflect radio waves. For this reason, when wireless communication is performed by a wireless LAN system through a wireless LAN base station antenna placed on the ceiling of a building, it is a wave that reaches not only a direct wave but also various propagation paths from the transmission point to the reception point. Multipath is likely to occur. For this reason, the signal level that can be received by the high-frequency antenna and the mobile wireless LAN slave antenna is greatly reduced, and the multipath component is increased, so that the reception S / N is lowered and high-speed communication becomes difficult. Therefore, an error is likely to occur in the position detection of the moving body. This problem occurs even in a normal indoor wireless LAN system, and becomes more prominent in a large building area.

  In addition, because there is a limit to the radio wave propagation range of the high-frequency antenna, the larger the indoor area is, the more high-frequency antennas are installed, and accordingly, the number of cables connected to the communication modem (control device) that is the base station device There is a complication that increases. For example, in Patent Document 1, when the position of a forklift is determined by dividing the indoor into 4 × 4 sections, a total of 16 high-frequency antennas are prepared, and 16 cables connected to each high-frequency antenna are connected to a single unit. To the base station equipment (control equipment).

  Therefore, when detecting the position of an indoor moving object using an indoor wireless LAN system, the influence of the reflected wave (multipath) is eliminated and the position of the moving object is detected without complicating the apparatus itself. Performing with high precision is an important issue.

  The present invention has been made in view of such circumstances, and its purpose is to simplify indoor movement and to move indoors with a wireless LAN system that can more accurately detect the position of an indoor moving body. The present invention seeks to provide a body position detection method and apparatus.

In order to achieve the above object, the gist of the position detection method of an indoor moving body using a wireless LAN system of the present invention is to arrange a plurality of high-frequency antennas, each independently connected to a wireless LAN base station apparatus, indoors. In addition, a wireless LAN slave unit provided with identification information for wireless communication with the wireless LAN base station apparatus is provided in an indoor mobile body, and the configuration of the high-frequency antenna has a plurality of directional antenna elements spaced apart from each other. As an arrangement on the high-frequency line, a communication area having a certain width is provided in parallel with the high-frequency line, while an indoor communication area is secured by arranging these high-frequency antennas in a lattice pattern in the indoor space. In addition, any two high-frequency antennas that intersect each other can be simultaneously wirelessly communicated to the wireless LAN slave unit of the mobile unit at an arbitrary indoor position. A wireless LAN terminal of the specific indoor mobile, the communication status with two high frequency antenna the crossing each other, and to determine the location of a specific indoor mobile.

  In addition, the gist of the position detection apparatus for indoor mobile objects using a wireless LAN system for use in the method of the present invention is that it is arranged indoors and is connected to a plurality of wireless LAN base station apparatuses independently connected to each other. A high-frequency antenna, and a wireless LAN slave device provided with identification information when wirelessly communicating with a wireless LAN base station apparatus provided in an indoor mobile body, each of the high-frequency antennas having an antenna element having directivity In addition to having a configuration in which a plurality of gaps are arranged on the high-frequency line, they are arranged in a lattice in the indoor space.

  In the present invention, the high-frequency antenna (a high-frequency antenna connected to a wireless LAN base station antenna or a wireless LAN base station device: hereinafter, the same meaning unless otherwise specified) includes a plurality of directional antenna elements spaced apart from each other. And a configuration arranged on a high-frequency line.

  In the present invention, the high-frequency antenna has a communication area having a certain width parallel to the high-frequency line by arranging the antenna element having directivity on the high-frequency line. Furthermore, in the present invention, the high-frequency antenna having such a configuration is arranged in a lattice shape above and below the indoor, and the arranged high-frequency antenna secures (covers) the entire necessary communication area indoors.

  Accordingly, any two high-frequency antennas intersecting each other can be simultaneously wirelessly communicated with the mobile wireless LAN slave unit at any position indoors. As a result, depending on the simultaneous communication status of the slave unit of the specific indoor mobile unit with the two base station apparatuses via any two high-frequency antennas intersecting each other, the vertical and horizontal in the indoor of the specific indoor mobile unit The coordinates (position) can be determined.

  In the present invention, an antenna element having directivity and preferably changing the polarization of adjacent ones is arranged on the high-frequency line. Therefore, compared to the conventional method of comparing the radio field intensity of the radio signal from the indoor mobile unit in each conventional high frequency antenna, walls, shelves, etc. that inevitably exist near the mobile unit It is hard to be influenced by the reflected wave (multipath) by the object. That is, regardless of the position of the mobile object indoors, it is possible to always ensure the communication status with the base station apparatus via any two high-frequency antennas without being affected by the reflected wave, and the accurate position of the mobile object Detection is possible.

  In addition, even in a wide area indoors, it is not necessary to increase the number of high-frequency antennas to be installed as in the conventional position detection device described above, and accordingly, a communication modem (control device) that is a base station device is connected. There is no complication of increasing the number of cables.

  Embodiments of the present invention will be described below with reference to the drawings. First, an indoor wireless LAN system as a premise of the present invention will be described with reference to FIG. FIG. 5 is a conceptual diagram showing an indoor wireless LAN system.

  In FIG. 5, a high frequency antenna (high frequency line) 1a constituting a wireless LAN base station antenna is provided, for example, along an indoor ceiling. This high-frequency antenna is preferably located above the indoors (above the area), such as the ceiling, in order to improve the visibility of the indoor antenna as a wireless LAN mobile station. However, depending on the indoor environment and usage conditions, the high-frequency antenna may be located below the floor (below the area), such as on the floor. Further, the upper arrangement and the lower arrangement of these high-frequency antennas may be appropriately combined for each indoor area.

  One end of the high-frequency antenna 1a is a non-reflective terminator, and the other end is connected to a wireless LAN base station device (also called a wireless LAN base station device or wireless LAN base unit) via a coaxial cable 12 or the like. 11 is connected. The wireless LAN base station device 11 is connected to the indoor mobile body position detection device 10 via an Ethernet cable 13 or the like. This position detection device 10 includes a hub (HUB: a multiport repeater that connects terminals in a star shape: a LAN component device having a signal reproduction and relay function) and a wireless LAN mobile station communicating with the wireless LAN base station device 11. Consists of devices that collect, process, and display information. The position detection device 10 may be further connected to an external network through a connection line.

  On the other hand, in FIG. 5, 9a, 9b, and 9c are slave units mounted on a moving body such as a person, a transport plane, and an object that move arbitrarily indoors (wireless LAN mobile station: a mobile station terminal such as a personal computer). Indicates. These slave units 9a, 9b, and 9c communicate with the antenna elements 6a and 6b in the high-frequency antenna 1 of the wireless LAN base station using, for example, antenna elements incorporated in the terminal wireless LAN card 5 respectively. . The terminal wireless LAN card 5 is provided with individual identification information for wireless communication for each mobile unit.

  The mobile body is assumed to be a transport vehicle such as a person, a forklift, a transport vehicle, etc., but these mobile bodies include slave units 9a, 9b, 9c having a wireless communication function such as the terminal wireless LAN card 5. Built-in or external. In the case of a forklift or the like, a dedicated terminal including a slave unit may be attached.

  Here, in the high-frequency antenna 1, the antenna elements 6a and 6b are provided with directivity so that the high-frequency antenna 1 has a communication area that is parallel to a high-frequency line to be described later and has a certain width.

  The high-frequency antenna 1 preferably has a configuration in which a plurality of antenna elements 6a and 6b adjacent to each other are alternately arranged with a plurality of intervals on a high-frequency line to be described later after changing the polarization of adjacent antenna elements 6a and 6b. This is because, as described above, each of the antenna elements in any two high-frequency antennas that intersect each other can be simultaneously wirelessly communicated with the indoor mobile unit at any indoor position. It is. Another reason is to eliminate the influence of multipath fading due to high-frequency interference between adjacent antenna elements 6a and 6b. If the polarization of the adjacent antenna elements 6a and 6b is not changed, there is a possibility that an area where communication is not possible due to cancellation of high frequencies may occur in some areas. If there is no inconvenience in position detection such as this area is small, it is not necessary to adopt means for changing the polarization between the adjacent antenna elements 6a and 6b. However, this means is preferably employed when there is a problem in position detection, such as when this area is large.

  The distance between the antenna elements 6a and 6b is determined in consideration of the height of the position (ceiling) where the high frequency antenna 1 (antenna element) is attached and the directivity of the antenna elements 6a and 6b. For example, when the high frequency antenna 1 is attached at a height of 3 m and the directivity of the antenna elements 6a and 6b is ± 45 degrees, they may be arranged at intervals of 6 m.

  Based on the configuration of the high-frequency antenna (wireless LAN base station antenna) as described above, an embodiment of position detection of an indoor moving body will be described below with reference to FIGS.

  FIG. 1 is a plan view showing an embodiment of a position detection device used in the present invention. FIG. 2 is a plan view showing a communication area of the high-frequency antenna in the indoor lateral direction (left-right direction in the figure) in the position detection apparatus of FIG. FIG. 3 is a plan view showing a communication area of a high-frequency antenna in the indoor vertical direction (vertical direction in the figure) in the position detection apparatus of FIG. FIG. 4 is a plan view showing a mode of detecting an indoor moving body based on FIGS.

  First, in FIG. 1, there are eight high-frequency antennas 1a to 1h having the same configuration as described in FIGS. 5 to 7 above the indoor, for example, an indoor ceiling 14 with a space therebetween. It arrange | positions at the grid | lattice form so that it may mutually parallel and cross | intersect. In this way, by placing the high-frequency antenna on the wireless LAN base station side above the indoor such as the ceiling, it becomes possible to see the mobile wireless LAN terminal antenna moving indoors, and direct waves The signal component is increased.

  In the indoor horizontal direction (left-right direction in the figure), four high-frequency antennas 1a, 1b, 1c, 1d are arranged in parallel to each other with a space therebetween. In addition, in the indoor vertical direction (vertical direction in the figure), four high-frequency antennas 1e, 1f, 1g, and 1h are arranged parallel to each other with a space therebetween. The indoor horizontal high-frequency antennas 1a, 1b, 1c, and 1d and the indoor vertical high-frequency antennas 1e, 1f, 1g, and 1h are arranged in a lattice pattern so as to cross each other so as to be orthogonal to each other.

  Each of these high frequency antennas is independently connected to a communication modem that is a wireless LAN base station apparatus 11a to 11h installed indoors. That is, the high frequency antenna 1a is the base station device 11a, the high frequency antenna 1b is the base station device 11b, the high frequency antenna 1c is the base station device 11c, the high frequency antenna 1d is the base station device 11d, and the high frequency antenna 1e is the base station device 11e. The high frequency antenna 1f is connected to the base station device 11f, the high frequency antenna 1g is connected to the base station device 11g, and the high frequency antenna 1h is connected to the base station device 11h. These wireless LAN base stations 11 are connected to a common indoor mobile body position detection apparatus 10 via Ethernet cables 13a to 13h, respectively.

As described above, in the present invention, a high frequency antenna is provided in a lattice pattern in an indoor area, and a wireless LAN base station apparatus is independently connected to each high frequency antenna. For this reason, N high frequency antennas and base station apparatuses are required in the vertical direction of the indoor area and N in the horizontal direction, and a total of 2 × N high frequency antennas and base station apparatuses are required. On the other hand, in the method of the conventional patent document 1, for example, when N high frequency antennas are provided in the vertical direction and N horizontal directions in the indoor area, N ² high frequency antennas and cables are required. Therefore, in order to increase the position detection accuracy of the moving body, when the N number needs to be increased or when the indoor area is wide, the difference in the number of high frequency antennas required between the present invention and the conventional method becomes larger. The advantages of the present invention are increased.

  Here, each of the high-frequency antennas has a configuration in which a plurality of directional antenna elements are arranged on a high-frequency line at intervals. For this reason, it has a wireless LAN communication area that is parallel to each high-frequency antenna (high-frequency line) and has a certain width. For example, as shown in FIG. 2, the high-frequency antenna 1a arranged in the indoor horizontal direction has a communication area 15a that is parallel to the indoor horizontal direction (left-right direction in the figure) and has a certain width. For this reason, the communication areas 15a, 15b, 15c, and 15d in the indoor lateral direction in FIG. 2 are secured by the four high-frequency antennas 1a, 1b, 1c, and 1d arranged in parallel in the indoor lateral direction.

  Similarly, as shown in FIG. 3, communication in the indoor vertical direction of FIG. 3 is performed by four high-frequency antennas 1e, 1f, 1g, and 1h arranged in parallel with the indoor vertical direction (vertical direction in the figure). Areas 16a, 16b, 16c and 16d are secured. Therefore, by arranging the high-frequency antennas on the indoor ceiling or the like in the form of a lattice spaced from each other, the horizontal and vertical communication areas overlap, and as shown in FIG. All necessary communication areas (all indoor moving areas of mobile objects) are covered.

  At this time, it should be noted that the communication areas of the adjacent high frequency antennas in the vertical direction or in the horizontal direction overlap well so as not to create a point where communication with the moving body cannot be performed by any high frequency antenna. The communication area width of each high frequency antenna can be adjusted by adjusting the transmission power from the base station apparatus 11 and the degree of coupling between the antenna element and the high frequency line. Also, changing the modulation method of wireless communication corresponds to controlling the S / N necessary for demodulation, so that the communication area width can be adjusted. For example, if a higher-order modulation method is used, communication can be performed only with a narrower communication area width and range.

  A method for detecting the position of an indoor moving body using the position detection device using the wireless LAN having the above configuration will be described below with reference to FIG. If the mobile unit 9a is at the position shown in Fig. 4 (solid circle), the mobile unit of the mobile unit 9a is within the communicable area (radio wave propagation range) of the mobile unit and is on the high-frequency antenna side. In addition, it communicates with the antenna element in the high-frequency antenna that is in the communicable area with the slave unit and has the same polarization as that of the antenna on the slave unit side.

  That is, in the case of the position shown in FIG. 4, the slave unit of the moving body 9a is arranged in the indoor horizontal direction with the antenna element 6a in the high frequency antenna 1g arranged in the indoor vertical direction that meets the above-mentioned conditions. The high-frequency antenna 1b communicates with the two antenna elements simultaneously with the antenna element 6a. However, depending on the surrounding environment, the high frequency from the antenna element 6a closest to the moving body 9a may not reach sufficient power for communication due to multipath.

  At this time, in the high-frequency antennas 1g and 1b, if the antenna element 6b adjacent to the antenna element 6a is different in the polarization of the antenna element 6a and the antenna on the slave unit, the antenna element 6a is replaced, Communication is performed with the mobile unit 9a (wireless LAN slave unit 5 in FIG. 5). This is because the mobile unit 9 of the mobile unit 9 is configured to scan the frequency channel to check the frequency channel of the base station and, if found, to use the frequency channel of the base station. Thus, if the polarizations of adjacent antenna elements in the high-frequency antennas 1g and 1b are made different, the influence of multipath can be eliminated and the communication state can be secured. In addition, transmission and reception between adjacent antenna elements in each high-frequency antenna do not interfere with each other.

  Further, when the moving body 9a moves to the position of the dotted line in FIG. 4 (downward in the figure), the antenna element 6a in the high-frequency antenna 1g (the antenna on the dotted line side below the antenna element 6a and the nearest antenna) Communication with element 6a) continues. As a result, communication between the handset side antenna and the high frequency antenna 1g is still continued.

  On the other hand, communication between the antenna on the handset side and the antenna element 6a in the high-frequency antenna 1b that is out of the possible communication area range is cut off. At the same time, instead of this, the antenna on the slave side in the high-frequency antenna 1c arranged in the horizontal direction and the nearest antenna element 6a start communication. As a result, even if the moving body 9a moves, communication with the two high-frequency antennas of the vertical and horizontal directions is always ensured, and the position after moving the mobile body 9a (indoor vertical and horizontal, so-called x and so on). (coordinate with y) can be detected continuously.

  In the communication situation between the antenna on the slave unit and the two high-frequency antennas crossing each other as described above, for example, the wireless LAN base station 11g via the high-frequency antenna 1g and the wireless LAN base via the high-frequency antenna 1b Communication with the mobile station 9a (wireless LAN slave unit 5 in FIG. 5) with the station 11b is input to the indoor mobile body position detection apparatus 10 via each of the ether cables 13g and 13b.

  The position detection device 10 reads data including a unique identification signal from the mobile body 9a, and determines the position of the mobile body 9a from the simultaneous communication status of the two high-frequency antennas 1g and 1b that intersect each other. It is determined that this is the intersection position (coordinates) between the two high-frequency antennas 1g and 1b. More specifically, it is determined that the position of the moving body 9a is a position where the antenna element 6a in the high frequency antenna 1g and the antenna element 6a in the high frequency antenna 1b can communicate simultaneously.

  In addition, when there are a plurality of mobile bodies 9, the position detection device 10 performs data communication with all the wireless LAN base stations 11, and each of the mobile devices 5 of each mobile body 9 communicating with each wireless LAN base station 11 It is also possible to obtain identification signal information and combine these pieces of information to determine the current position of each mobile body 9 and display it if necessary.

  At this time, the frequency channels transmitted and received by each wireless LAN base station 11 may be the same. The frequency channel used by the handset 5 of the mobile unit 9 depends on the frequency channel of the base station. That is, as described above, the handset 5 of the mobile unit 9 is configured to scan the frequency channel to check the frequency channel of the base station and, if found, use the frequency channel of the base station. However, in this case, other radios do not transmit data during the time when one radio (two base stations and mobile unit) transmits data for communication. Like that. In the case of using the same frequency channel, the same frequency channel is divided and used in time, so that there is a problem that as the number of wireless devices increases, a collision easily occurs during data transmission.

  In such a case, it is preferable that the frequency channels transmitted and received by each wireless LAN base station 11 are different. For example, the indoor vertical base station devices 11a, 11b, 11c, and 11d in FIG. 1 are the same frequency channel, the horizontal base station devices 11e, 11f, 11g, and 11h are the vertical base station devices. Different and the same frequency channel may be used. In this case, since the frequency channel on the handset side needs to communicate with two high-frequency antennas in the vertical and horizontal directions at the same time, the frequency channel of the vertical base station device and the frequency of the base station device in the horizontal direction It is necessary to have a frequency channel.

  Furthermore, if different frequency channels are used between adjacent base station apparatuses, the communication speed is improved without causing radio wave interference, which contributes to speeding up of position detection. For example, indoor vertical base station apparatuses 11a and 11c in FIG. 1 use frequency channel No. 1, vertical base station apparatuses 11b and 11d use frequency channel No. 2, and horizontal direction Base station apparatuses 11e and 11g use frequency channel No. 3, and horizontal base station apparatuses 11f and 11h use frequency channel No. 4. At present, indoor wireless LAN devices can be used in the 2.4 GHz band and 5.2 GHz band, and thus multiple frequency channels can be used simultaneously. In this case, the frequency channel on the handset side has one or more types of frequency channels No. 1 to 4 selected according to the necessity of the position detection accuracy of the moving body.

  Next, the aspect of the more concrete structure of the high frequency antenna used by this invention is demonstrated below. FIG. 6 shows a high-frequency antenna (high-frequency line) for a wireless LAN system, (a) is a perspective view of the high-frequency antenna 1a, and (b) is a cross-sectional view of the high-frequency antenna 1a. FIG. 7 is a perspective view showing a circularly polarized antenna element in a high-frequency antenna.

  In the following description, a high-frequency microstrip line structure in which a dielectric layer and a signal line are sequentially laminated on a ground layer will be described as a preferable aspect of the high-frequency line constituting the high-frequency antenna. In the present invention, as a high-frequency line constituting a wireless LAN base station antenna, a waveguide made of a conductive metal such as stainless steel, steel, copper, or aluminum, or a micro wave other than a waveguide such as a coaxial cable is used. Although it can also be used in a wave transmission line, it has inferior characteristics such as thinness, flexibility and workability as compared with the high-frequency microstrip line 1a as shown in FIG.

  In FIG. 6 (a), the high-frequency line constituting the high-frequency antenna 1a has a long thin plate shape having a length necessary for the wireless LAN system in the area. 6 (a) and 6 (b), the structure in the cross-sectional (thickness) direction of the high-frequency line is as follows: a ground layer 3 made of a conductor material, a dielectric layer 2 made of a dielectric material, and a signal for high-frequency induction made of a conductor material It has a high frequency microstrip line structure in which the wires 4 are sequentially laminated in the order of description. The signal line 4 is disposed in the longitudinal direction of the high frequency line. Here, the high frequency line has flexibility. Note that a known adhesive material such as a double-sided adhesive tape or an adhesive sheet or an adhesive layer may be provided on the bottom surface of the high-frequency line to facilitate attachment / detachment and installation of the high-frequency line.

  Such a strip-shaped high-frequency line is also referred to as a high-frequency microstrip line. A high-frequency line in which a long dielectric layer made of a dielectric material and a signal line are sequentially laminated on a pair of long ground layers made of a conductive material. The microstrip line has a configuration in which a plurality of directional antenna elements are arranged at intervals. Such a high-frequency microstrip line has flexibility, the line itself can be freely deformed according to the purpose, and the obstacle is exceeded or detoured depending on the installation conditions in the wireless LAN system area. Suitable for macro installation. In addition, handling such as installation work and transportation to the installation site is also simple.

  Next, a specific configuration of a high-frequency antenna provided with an antenna element is shown in FIG. In FIG. 7, antenna elements 6a and 6b in the high-frequency antenna 1a are patch antennas that are circularly polarized antenna elements. The basic structure of this patch antenna is configured, for example, by sequentially laminating a dielectric plate 8 made of a dielectric material and a patch (radiating plate) 7 made of a conductive material. These patch antennas are arranged on the signal line 4 of the high-frequency line in FIG. 6 and are electrically coupled to the signal line 4.

  In the example of FIG. 5 described above, the antenna elements 6a and 6b are adjacent to each other in order to have directivity, and to eliminate the influence of multipath fading due to high-frequency interference between the adjacent antennas 6a and 6b. The turning directions of the patch antennas are different from each other. That is, the patch antenna 6a is a clockwise clockwise circularly polarized antenna element, the adjacent patch antenna 6b is a counterclockwise left circularly polarized antenna element, and these circularly polarized antenna elements are alternately arranged. .

  As the conductive material constituting the patch 7, the same metal material as the conductive material constituting the ground layer of the high-frequency line can be applied. As the dielectric material constituting the dielectric 8a, the same material as the low-loss resin dielectric material constituting the dielectric of the high-frequency line is selected.

  As a means for electrical coupling between the patch antenna and the signal line 4 of the high-frequency line, any appropriate means can be adopted other than arranging the patch antenna on the signal line. For example, a patch antenna may be disposed beside the signal line 4 and a feeder line may be disposed for electrical coupling.

  With the configuration of the patch antenna, the antenna elements 6a and 6b can be easily attached to and detached from the high-frequency antenna 1a. Therefore, even if there is a change in the antenna layout of the wireless LAN system, such as a change in the indoor layout, if the entire indoor area can be covered with the high-frequency antenna, basically, depending on the new layout, It is only necessary to attach and remove the patch antenna, and there is no need to redo the installation work of the high-frequency line itself. Also, adjust the conditions such as the material and thickness of the radiating plate and dielectric on the side of the patch antenna, even when correction of the radio frequency to be used is required for the main characteristics such as the coupling degree and gain of the antenna element. The correction can be made easily by using a patch antenna adjusted to the conditions to be adapted.

  In order to reduce the influence of multipath fading due to high-frequency interference between adjacent antenna elements 6a and 6b in order to make the antenna element directivity after using the patch antenna as described above, In this embodiment, the circularly polarized antenna elements 6a and 6b are circularly polarized waves, and the circularly polarized waves have different turning directions, such as a clockwise clockwise circularly polarized antenna element and a counterclockwise counterclockwise circularly polarized antenna element. A plurality of antenna elements are arranged on the high-frequency antenna 1a at intervals.

  In order to give the patch antenna a turning direction as a circularly polarized antenna element, as shown in Fig. 7, the two opposite corners (corner portions) of the square (rectangular) patch 7 were dropped ( The shape is notched. In FIG. 7, the adjacent patch antenna 6a is a right-hand circularly polarized antenna element turning right, and the patch antenna 6b is a left-hand circularly polarized antenna element turning left. For this reason, as shown in FIG. 7, the patch antenna 6a, which is a right circularly polarized antenna element, drops two opposite corners on the upper left and lower right in FIG. 6b drops the two opposite corners of the upper right and lower left in Fig. 7.

  By changing the direction of notches at the two opposite corners of the patch 7, the antenna turning direction of the circularly polarized antenna element, that is, the right circularly polarized wave or the left circularly polarized wave, can be controlled. The planar shape of the patch (radiating plate) 7 and the control of the antenna turning direction can be controlled by a circularly polarized antenna element other than the rectangular shape shown in FIG. Any shape that can control the turning direction can be selected.

  On the other hand, the high-frequency antenna on the slave unit mounted on the mobile body can be basically configured in the same manner as the wireless LAN base station-side high-frequency antenna, including a patch antenna that is a circularly polarized antenna element. When multiple circularly polarized antenna elements with different antenna turning directions are present in both the base station side high frequency antenna and the mobile unit side high frequency antenna, it is less susceptible to multipath, ensuring good communication and moving. Body position detection is ensured.

  Here, the dielectric layer 2 of the high-frequency antenna 1a shown in FIGS. 6 to 7 does not have a ground layer on the surface of the dielectric layer 2 on the signal line 4 side, and even if this surface side is fully opened, Conditions that do not cause loss are appropriately selected. In general, high-frequency loss from a high-frequency line is roughly classified into radiation loss, conductor loss, and dielectric loss. Among these, in order to reduce the radiation loss, it is preferable to increase the dielectric constant of the dielectric layer 2. This dielectric constant is determined from the dielectric constant of the dielectric material itself constituting the dielectric layer 2 and the thickness of the dielectric layer 2. For this reason, it is preferable to select the thickness of the dielectric material and the dielectric layer so as to increase the dielectric constant. However, as the thickness of the material having a high dielectric constant or the dielectric layer increases, the flexibility is lost. Therefore, when flexibility is required, the optimum material and the thickness of the dielectric layer should be determined in consideration of this. select.

  Further, since the conductor loss becomes smaller as the electric conductivity of the signal line 4 becomes higher, it is preferable to determine the optimum electric conductivity of the signal line 4 from the electric conductivity necessary for the high-frequency line. Furthermore, since the dielectric loss is determined by the dielectric material itself constituting the dielectric layer 2, it is preferable to select a low dielectric loss material. However, the width and thickness of the dielectric layer 2 are required to have a certain width and thickness depending on the relationship between the frequency of the signal required for the wireless LAN system and the loss of high frequency. In this regard, for example, on the basis of a standard indoor wireless LAN system such as an office, it is preferable that the thickness is 0.1 to 2.0 mm and the width is about 10 to 50 mm.

  Accordingly, as the dielectric material for the dielectric layer 2, it is preferable to select a material that does not cause high-frequency radiation loss and has a low dielectric loss on the premise of the width and thickness of the dielectric layer 2 selected from the above-described preferred range. The dielectric material itself can be selected from resin dielectric materials such as Teflon (registered trademark), polyimide, polyethylene, polystyrene, polycarbonate, vinyl, and mylar. It is preferable to select and use as a composition or a mixture of a plurality of these. These resin dielectric materials can maintain desired flexibility required for a high-frequency line by setting conditions such as composition.

  The overall thickness of the high-frequency line in the high-frequency antenna 1a is preferably as thin as 2 mm or less for the purpose of reducing the cross-sectional area and volume of the high-frequency line. Therefore, the thickness of the ground layer 3 and the signal line 4 is preferably as thin as possible for this purpose. The thickness of the ground layer 3 is preferably 0.2 mm or less as long as the required thin plate strength can be ensured. The width of the ground layer 3 corresponds to the width of the dielectric layer 2 so as to cover the dielectric layer 2 and suppress high-frequency loss.

  The conductive material constituting the ground layer 3 includes various metals, alloys such as copper, aluminum, tin, gold, nickel, and solder, and various kinds of these metals and alloys plated on composite, laminated, or resin substrates. The aspect is appropriately selected as the highly conductive metal material. Among these, a metal material which can be easily processed into a thin plate, has a flexibility corresponding to the dielectric material, and further has a required thin plate strength is preferable.

  As the signal line 4 for high frequency induction, a fine wire or a thin plate of the above-mentioned highly conductive metal material is selected. The signal line 4 may be projected or placed on the dielectric layer 2 as shown in the high-frequency line 1a of FIG. 2, or embedded in the dielectric layer 2 in the longitudinal direction of the high-frequency line 1a. It may be arranged.

  The high-frequency microstrip line having the above configuration is thin and flexible, so that it is not only a long plate shape, but also a long coil shape wound around the high-frequency line. Easy to handle. Moreover, it has excellent basic characteristics as a high-frequency line, such as low-loss propagation of high-frequency waves.

  As described above, according to the present invention, the device itself is simplified even if it is a large indoor space, and is not easily affected by multipath indoors, and the position of an indoor moving body can be detected more accurately. A position detection device for indoor moving objects can be provided using a wireless LAN system. For this reason, the present invention is suitable for a larger indoor position detection device such as a large structure, building, factory, or venue.

It is a top view which shows the embodiment of this invention indoor mobile body position detection apparatus. FIG. 2 is a plan view showing a communication area of a high frequency antenna in the indoor lateral direction in the position detection apparatus of FIG. FIG. 2 is a plan view showing a communication area of a high-frequency antenna in the indoor vertical direction in the position detection device of FIG. It is a top view which shows the aspect which detects an indoor moving body. 1 is a conceptual diagram showing one embodiment of an indoor wireless LAN system as a premise of the present invention. FIG. 6 (a) is a perspective view and FIG. 6 (b) is a sectional view showing one embodiment of a high-frequency antenna (high-frequency line) in a wireless LAN system. It is a perspective view which shows one embodiment of the high frequency antenna which provided the circularly polarized antenna element.

Explanation of symbols

1: high frequency antenna, 2: dielectric layer, 3: ground layer, 4: signal line,
5: Wireless LAN card for terminal, 6: Patch antenna, 7: Patch,
8: Dielectric layer, 9: Mobile terminal, 10: Position detection device, 11: Base station device,
12: Coaxial cable, 13: Ether cable, 14: Indoor ceiling, 15: Communication area,
16: Communication area,

Claims (5)

  A method for detecting the position of an indoor moving body using a wireless LAN system, in which a plurality of high-frequency antennas each independently connected to a wireless LAN base station device are arranged indoors and wirelessly communicated with the wireless LAN base station device. A wireless LAN cordless handset provided with identification information at the time is provided in an indoor moving body, and the configuration of the high frequency antenna is configured by arranging a plurality of directional antenna elements on a high frequency line at intervals. The high-frequency antennas are arranged in a lattice pattern at intervals in the indoor space, while securing an indoor communication area and any two of them intersecting each other. Wireless communication is possible simultaneously with the mobile LAN slave unit of the mobile unit where the high-frequency antenna is located indoors. The communication status with two of the radio-frequency antenna which cross each other, the position detecting method of indoor mobile wireless LAN system, characterized in that the location of the specific indoor mobile.   The method for detecting a position of an indoor moving body by a wireless LAN system according to claim 1, wherein the high-frequency line is a high-frequency microstrip line in which a dielectric layer and a signal line are sequentially laminated on a ground layer.   The position detection method of the indoor moving body by the wireless LAN system of Claim 2 which changed the polarization | polarized-light of the adjacent antenna elements arrange | positioned at the said high frequency microstrip line.   The method for detecting a position of an indoor moving body by a wireless LAN system according to any one of claims 1 to 3, wherein frequency channels transmitted and received by each wireless LAN base station device are different from each other. A device used for the position detection method of an indoor mobile body by the wireless LAN system according to any one of claims 1 to 4, wherein the plurality of devices are arranged indoors and are independently connected to the wireless LAN base station device. A high frequency antenna and a wireless LAN slave unit provided in an indoor mobile body and given identification information when wirelessly communicating with a wireless LAN base station device, each of the high frequency antennas having a directivity Detecting the position of an indoor moving body by a wireless LAN system, wherein a plurality of elements are arranged on a high-frequency line at intervals, and are arranged in a lattice at intervals in the indoor space apparatus.

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