JP2021150941A - Coordinates and map generation by wireless mesh network - Google Patents

Abstract

To specify the coordinates of all wireless devices at an arbitrary time, enhance accuracy, and facilitate additional installation, when a vast wireless mesh network is constructed in the wireless devices including mobile stations.SOLUTION: When a vast wireless mesh network is constructed in wireless devices (which may include fixed stations) including mobile stations, all wireless devices including mobile stations measure the distance with each other, share, and form relative coordinates to create map data. In addition, the center point (center of gravity) is specified.SELECTED DRAWING: Figure 9

Description

Regarding the generation of coordinates and map generation of all radios in a configuration in which a wireless mesh network is constructed with three or more radios.

In the case of indoors, as an example, the following method of specifying the position (coordinates) by the prior art is known.
-A function to measure the distance from the radio wave strength emitted by another radio (RSSI function, beacon function, etc.) to the other radio within the range where wireless communication is possible (Fig. 3),
Currently, it is a technology realized by beacons using Bluetooth and the like.
-A function to communicate with other wireless devices within the range where wireless communication is possible (Fig. 4),
Currently, it is a technology that is possible with Bluetooth mesh.
-A function to identify the coordinates of the unknown one-point radio by three-range multilateration from the coordinates of the known two-point radio and the distance to the unknown one-point radio (Fig. 5).
It is a calculation method realized by surveying technology.

Further, when it is outdoors, the position identification by the following prior art is known.
・ GPS positioning function

Further, it is known that the position can be specified by a combination of the above-mentioned conventional techniques.
Furthermore, in order to specify the coordinates and positions of all wireless devices in a vast wireless network by the prior art, centralized management by a special fixed station base station, host computer, access point, etc. has been used.

However, when specifying the coordinates and positions of all wireless devices in a vast wireless network using conventional technology, it is necessary to increase the number of base stations, host computers, and access points of special fixed stations, or to follow mobile stations. It was not possible or could not be identified at any time, and when installing additional radios, it was necessary to set the base station, host computer and access point of the fixed station, and GPS was used outdoors. Even in that case, there were restrictions such as cost, power consumption, increase in size, and installation of GPS antennas.

One of the problems of the current IoT is that it is not easy to manage a large number of sensors and devices, so that the management may be complicated, and the management may not be perfect and the data may not be utilized.

In the future IoT, more sensors and devices will be wirelessly connected to the Internet compared to the current situation, and a vast wireless network (wireless mesh network, multi-hop network, etc.) will be constructed.
By increasing the number
-Importance of location information management-Cost, power consumption, size reduction-Following mobile stations-Inevitably, the demand for ease of installation will increase.

The means of claim 1

The present invention wirelessly creates a map at an arbitrary time while following a mobile station without using a special base station, host computer, access point, or the like, and without using positioning information such as GPS. All radios (radio that specify coordinates) including mobile stations arranged in the mesh network have the following functions.
・ Measure distances with each other by functions such as RSSI and beacon ・ Exchange all measured distance values with each other by unicast address communication ・ Specify coordinates by three-sided survey ・ Radio that is common to the results of three-sided survey Specify relative coordinates from ・ Collect relative coordinates by group address communication ・ Create map data ・ Execute at arbitrary time

An outline configuration example of the hardware of the radio is shown (Fig. 1). As a configuration, it can be configured by a general CPU and its peripheral devices. CPU for processing programs, non-volatile memory for storing programs and data, non-volatile memory for storing values and data required for program execution, timers, AES and UUID required for program execution, and wireless communication. Implement RF and, if necessary, external interface IO, DMA, PWM, etc.

A configuration example of a wireless mesh network (relative coordinate network) is shown (Fig. 2). When the radio can communicate with other radios at two or more points, the coordinates can be specified. In the case where only one point can communicate with another radio (radio m), the data is provided only as the distance, not the coordinates (Fig. 2 m). If it is possible to communicate with another radio at two or more points, but the distance between the other radios cannot be measured and the three-sided survey method cannot be performed (radio k), the radio that can communicate to form a triangle from the map data. The distance of (radio j, radio l) is calculated, and the coordinates are specified by the three-sided survey method (radio k, radio j, radio l) (FIG. 2 j, k, l).

The details of the radio will be described below.

First, an example of the prior art to be used will be described.

Explanation of the function of measuring the distance with each other by the functions such as RSSI and beacon (Fig. 3).

Currently, it is a technology that can realize a beacon using Bluetooth or the like. The radio a measures the distance from the radio wave intensity emitted by the radio b (beacon, RSSI value, etc.) to the radio b (FIG. 3 ab distance). The radio a measures the distance from the radio wave intensity emitted by the radio c (beacon, RSSI value, etc.) to the radio c (FIG. 3 a-c distance). The radio a measures the distance from the radio field intensity emitted by the radio d (beacon, RSSI value, etc.) to the radio d (FIG. 3ad distance). Similarly, the radio b, the radio c, and the radio d also measure the distances to all the other radios facing each other.

Description of the function of exchanging the measured values of all distances with each other by unicast address communication (Fig. 4).

As a method of exchanging distance values with each other by a wireless mesh network, communication using a unicast address of Bluetooth mesh (point-to-point two-point communication) is used. Bluetooth mesh is a standard that can be both a wireless server model and a client model, and can communicate with each other at two points, Point to Point. To send the coordinates (sending side), use the client model and publish to the unicast address (address of each radio on the receiving side). The side receiving the coordinates (receiving side) uses the server model and subscribes. The radio a requests the opposite radio b, c, and d to transmit the measured distance. The radio b, the radio c, and the radio d respond to the request of the radio a.

Explanation of the function of specifying coordinates by three-sided survey (Fig. 5).

The radio a is set to 0 (distance a-) of either the coordinates (0,0) of the radio a or the coordinates XY of the radio b from the three distances of the radio a, the radio b, and the radio c. Let b, 0) be set, and the coordinates of the C radio are specified by three-sided survey. Similarly, the radio a is set to the coordinates of the radio a (0,0) and the coordinates of the radio c (distances ac, 0) from the three distances of the radio a, the radio c, and the radio d, and is wireless. The coordinates of the machine d are specified by three-sided survey.

Next, the present invention will be described.

First, all radios (radio for specifying coordinates) including the mobile station of the wireless mesh network are premised on the use of the above-mentioned prior art example.

The function of specifying the relative coordinates from the radio that is common to the results of the three-sided survey will be explained. (Fig. 6)

Since the radio a is common to the radio c, the relative coordinates of the radio d are respecified with the distance a-c as the tangent to the triangle. Similarly, the radio a is calculated by the radio a, the radio c, and the radio e to specify the relative coordinates of the radio e. At this time, the process proceeds while specifying the center point (center of gravity) while performing claim 3. When the radio can communicate with other radios at two or more points, the relative coordinates can be specified, but when there is only one point that can communicate with other radios, the data is not the coordinates but only the distance. (Fig. 2 m). It is possible to communicate with other radios at two or more points, but if the three-sided survey method is not possible (radio k), the distance of the communicable radios (radio j, radio l) forming a triangle is set. Obtained by calculation, and the relative coordinates are specified by the three-sided survey method (radio k, radio j, radio l) (Fig. 2 j, k, l).

The function of collecting relative coordinates by group address communication will be described.

As a method of collecting the relative coordinates in the wireless mesh network, the group address (multicast communication) of the Bluetooth mesh network is used. The Bluetooth mesh can set a plurality of group addresses, and the radio that collects the relative coordinates in advance sets the relative coordinate group address. Relative coordinates can be collected from all the radios set in the group by sending and receiving only once to the relative coordinate group address from a certain radio. The radio that sends the relative coordinates (sender) publishes to the group address using the client model. The radio that collects relative coordinates (reception side) subscribes to the group address using the server model.

The function of creating map data will be explained.

As a method of creating map data, the same radio is set to the same coordinates from the collected relative coordinates and combined. For the combination, the radio that serves as the starting point is determined, and the radios are combined radially from the radio. FIG. 7 shows an example starting from the radio a. (FIG. 8) The radio a has the radio a and the radio b based on the relative coordinates of the radio b specified by the radio a and the relative coordinates of the radio a specified by the radio b collected from the radio mesh network. The relative coordinates of the two radios are matched and combined. At this time, the angle is adjusted by using a trigonometric function or the like. Similarly, the relative coordinates of the radio c, the radio d, and the radio e are collected from the wireless mesh network and combined. Next, since the radio c has relative coordinates of the radio f, the radio g, and the radio h outside the range in which the radio communication of the radio a can be performed, the radio f, the radio g, and the radio h have relative coordinates. Coordinates Relative coordinates are collected and combined from group address communication (multiplex communication). By combining them radially in this way, it is possible to create vast map data. Further, at this time, the process proceeds while specifying the center point (center of gravity) while performing claim 3.

The function to be executed at an arbitrary time will be described. (Fig. 9)

Map data is created at an arbitrary time by repeating the following operations.・ 1. All radios, including mobile stations in wireless mesh networks, emit beacons at any time.・ 2. All radios including mobile stations in the wireless mesh network measure and record the distance to the other radio by the signal strength of the beacon received from the other radio.・ 3. All radios, including mobile stations in the wireless mesh network, request the other radios that have transmitted the beacon to transmit all the recorded radios and their distances.・ 4. The other radio that receives the request returns all the recorded radios and their distances.・ 5. All radios, including mobile stations in the wireless mesh network, perform three-range multilateration together with the radios that have been replied by other radios and their distances.・ 6. All radios including mobile stations in the wireless mesh network find the tangent line of the triangle from the radio with the same coordinates, and use the triangular function etc. to obtain the relative coordinates of other radios within the range where wireless communication is possible. To identify.・ 7. All radios, including mobile stations within the wireless mesh network, multicast relative coordinates to the wireless mesh network.・ 8. Create map data using trigonometric functions.

The means of claim 2

In addition to the function of claim 1, a function of specifying a center point (center of gravity) when there is an error in the relative coordinates of the radio and providing highly accurate relative coordinates will be described. (Fig. 10)

Starting from a radio with a small error, the center point (center of gravity) is sequentially specified radially from the radio. For example, the radio a records four measured distances ab, ac, ad, and a, and the distances b a and a b measured by the radio b, and the radio c. The distances c-a and a-c measured by the radio device d, the distances d-a and a-d measured by the radio device d, and the distances e-a and a-e measured by the radio device e are used for the ratio. As a result of comparison, the radio with the least difference in distance is set as the first starting point. The second starting point is the radio that has no difference in the second distance. If the first starting point is the radio b and the second starting point is the radio c, the radio a first finds the centers of the distances baa and ab, and then sets the distances ca. When there is an error between the coordinates of the radio d obtained from the radio b and the seat of the radio d obtained from the radio c, the center point (center of gravity) is wirelessly obtained. Determined as the relative coordinates of the machine d.

Means of claim 3

In addition to the function of claim 1, a function of specifying a center point (center of gravity) when there is an error in relative coordinates when creating map data and providing highly accurate map data will be described. (Fig. 11)

The order is not limited, but the starting point radio is determined, and the center point (center of gravity) is sequentially specified radially from the radio. For example, in the radio a, when the starting radios are the radios b and c, the relative coordinates of the radio b specified by the radio a and the radio b specified by the radio b collected from the radio mesh network are used. From the relative coordinates of a, the relative coordinates of the two radios, the radio a and the radio b, are matched and combined. At this time, the angle is adjusted by using a trigonometric function or the like. Similarly, the radio a and the radio c also match and combine the relative coordinates of the two radios. At this time, the radio f is included in both the relative coordinates of the radio b and the radio c, and the coordinates of the radio f obtained from the radio b and the radio f obtained from the radio c When there is an error in the seat, the center point (center of gravity) is determined as the relative coordinates of the radio f. In this way, the relative coordinates are determined radially in order, and the map data of all the radios of the wireless mesh network is created.

The means of claim 4

The map data created in claims 1, 2 and 3 have relative coordinates, and a function of converting the map data into absolute coordinates will be described. Register the position information that is the source of the absolute coordinates in two or more radios in the wireless mesh network. The location information and the information of the radio that registered it are sent by the registered radio to all radios including mobile stations in the wireless mesh network. All radios including mobile stations in the wireless network convert the received two or more position information into absolute coordinates by trigonometric function. As a method of sending location information, a group address (multicast communication) of a Bluetooth mesh network is used. The Bluetooth mesh can set a plurality of group addresses, and the radio that collects the position information in advance sets the position information group. Position information can be obtained from all the radios set in the group by sending and receiving only once to the position information group from a certain radio. The radio that sends the location information (sender) publishes to the group address using the client model. The radio that collects location information (receiver) subscribes to the group address using the server model.

When a vast wireless mesh network is constructed with wireless devices including mobile stations,
-Coordinates (position information) can be acquired at any time-Following mobile stations is possible-Easy installation is possible-Total cost, power consumption, and size can be reduced.

This is an example of a wireless device hardware configuration. This is an example of a wireless network configuration. It is a conceptual diagram of the distance measurement by the wireless mesh network performed by all radios. (Previous technology) It is a conceptual diagram of the distance data transmission / reception performed by all radios. (Previous technology) It is a conceptual diagram of three-sided surveying and coordinate identification performed by all radios. (Previous technology) It is a conceptual diagram which specifies a relative coordinate by a tangent line performed by all radios. It is a conceptual diagram which creates map data from a relative coordinate network using a wireless mesh network. It is a conceptual diagram which creates map data radially starting from a radio a. It is a flowchart which repeats operation at an arbitrary time performed by all radios. It is a conceptual diagram which specifies the coordinates by the center point (center of gravity) performed by all radios. It is a conceptual diagram which creates map data by the center point (center of gravity) performed by all or some radios.

Claims (4)

With a configuration that builds a wireless mesh network with wireless devices that include three or more mobile stations.
All radios (radio that specify coordinates) including mobile stations have unicast address communication (point-to-point two-point communication) and group address communication (multicast communication) functions.
All radios, including mobile stations, measure distances with each other within the range where wireless communication is possible by functions such as RSSI and beacons, and the values of all distances measured with each other are mutually measured by unicast address communication. It has a function to exchange and re-identify the coordinates of the unknown one-point radio by three-sided measurement from the coordinates of the known two-point radio and the distance to the unknown one-point radio.
All radios including mobile stations in the wireless mesh network are relative to other radios within the range where wireless communication is possible using common radios, trigonometric functions, etc., together with the results of three-sided survey. It has a function to specify the coordinates,
All radios, including mobile stations in wireless mesh networks, have the ability to communicate relative coordinates in group addresses.
Some or all radios, including mobile stations in the radio mesh network, form a relative coordinate network consisting of radios with specific relative coordinates, and collect, combine, and combine relative coordinates from group address communications. Radio that creates map data All the radios including the mobile station in the wireless mesh network of claim 1 obtain the tangent line of the triangle from the radio having the same coordinates, and use other radios within the range where wireless communication is possible by using the triangular function or the like. It has a function to specify the relative coordinates of the machine,
As a result of specifying the relative coordinates, when there is an error in each coordinate, it has a function to specify the radio with a small error distance.
A radio that identifies the center point (center of gravity) radially from the radio that started. The wireless mesh network of claim 1 Some or all of the radios including the mobile station in the network form a relative coordinate network composed of radios whose relative coordinates are specified, and the relative coordinates are collected and combined to form a triangle. It has a function to create map data using functions, etc.
As a result of combining, when there is an error in the coordinates, the radio that will be the starting point (for example, the first radio) is determined, the center point (center of gravity) is sequentially specified radially from that radio, and the overall map data is highly accurate. Radio to create. It has a function of registering position information in order to convert the relative coordinates of the map data created in claims 1, 2 and 3 into absolute coordinates.
The wireless registration in which the location information is registered has a function of transmitting the location information through a wireless mesh network (for example, communication using a group address of Bluetooth mesh = multicast communication).
All radios, including mobile stations in a wireless mesh network, are radios that convert two or more received location information into absolute coordinates.

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