Use Wi-Fi Based Positioning for Non-GPS Locations

Your project can use Wi-Fi based positioning for indoor scenarios where GPS signal is lacking. Your wireless devices and Access Points (APs) must support the Wi-Fi RTT (Round Trip Time) feature.

Wi-Fi RTT (Round-Trip-Time) lets your Wi-Fi devices measure the distance to nearby RTT-capable Wi-Fi access points and peer devices. Several Android 9 and Android 10 mobile devices support Wi-Fi RTT. Wi-Fi based positioning results usually have accuracy precisions between one and two meters.

To use Wi-Fi based positioning in Oracle IoT Connected Worker Cloud Service, you need to configure your Wi-Fi RTT access points and positioning settings. You can then add the positioning settings to your project.

You need to create a Cartesian coordinate system for your location, such that each point can be identified by its x,y, and z coordinates. You do this by specifying the coordinates for the start point and end point. The start point and end point can be the opposite corners of your location. You also specify the latitude, longitude, and altitude values for the start point and end point to complete the mapping.

For example, if you choose the bottom left corner of your floor plan as the start point, you can choose the top right corner as the end point. The floor plan would usually have the distance measurements for your location. You can also physically measure the distances. The Cartesian coordinates are specified in millimeters (mm).

Wi-Fi RTT access points, such as Wi-Fi routers, are identified by their hardware MAC addresses. You also need to specify the Cartesian coordinates of the access points based on their distances from the start point.

After configuring the access points and the positioning settings, you can add one or more set of positioning settings for your project. The following sections describe these steps.

Identify Your Wi-Fi Access Points

Each Wi-Fi access point is identified by its hardware or MAC address. For successful trilateration of a device or user position, at least three access points are required in a plane. For 3-dimensional space, at least four access points are required.

1. Click Menu and then click Design Center.
2. Click the Access Points tab.
3. Click Create New .
4. Enter a Name for the access point.
5. (Optional) Enter a Description for the access point.
6. Specify the MAC address for the access point.
   The MAC address consists of six pairs of hexadecimal numbers separated by colons ( : ) or hyphens ( - ).
7. Click Save.

Repeat the preceding steps to identify additional access points.

Configure Positioning Settings and Access Points

Complete the Cartesian mapping for your location by specifying the Cartesian coordinates and the corresponding latitude, longitude, and altitude values for two points in the location. Also specify the Cartesian coordinates for your access points.

1. Click Menu and then click Design Center.
2. Click the Positioning tab.
3. Click Create New .
4. Enter a Name for the positioning settings.
5. (Optional) Enter a Description for the positioning settings.
6. Enter the Number of History Points to use.
   Specifies the number of historical points to be included in the moving average. Multiple points in an average help get more precise locations. Every access point has an associated entry in the history of observed ranging results.
7. Enter the Ranging Request Period in milliseconds.
   Ranging requests are used to measure the distances to nearby RTT-capable Wi-Fi access points and peer Wi-Fi devices. The ranging request period is the time period, in milliseconds, between successive ranging requests.
8. Complete the Start Point Cartesian Mapping.
   You need to specify the Cartesian coordinates, latitude, longitude, and altitude values for the start point. The start point can be one corner of your floor plan.
   1. Specify Coordinate X, Coordinate Y, and Coordinate Z values for your start point.
      These are the x, y, and z coordinates for your start point in millimeters. For example, start coordinates of [0,0,300] implies that the start point for your Cartesian map is 300 mm or 30 cms on the z-axis. The x and y coordinates are 0.
   2. Specify the Latitude, Longitude, and Altitude values for the start point.
      This maps the Cartesian coordinates to their corresponding Geo-coordinates.
9. Complete the End Point Cartesian Mapping.
   You need to specify the Cartesian coordinates, latitude, longitude, and altitude values for the end point. The end point can be the corner opposite to your start point on the floor plan. For example, if the start point is the lower left hand corner, the end point can be the upper right corner.
   1. Specify Coordinate X, Coordinate Y, and Coordinate Z values for your end point.
      These are the x, y, and z coordinates for the end point in millimeters. For example, end coordinates of [30000,20000,300] implies that the start point for your Cartesian map is 30 meters along the x-axis, 20 meters along the y-axis, and 30cms along the z-axis.
      The floor plan would usually have the distance measurements for your location. You can also physically measure the distances.
   2. Specify the Latitude, Longitude, and Altitude values for the end point.
      This maps the Cartesian coordinates to their corresponding Geo-coordinates.
10. Complete the configuration for your Wi-Fi access points.
    1. Click Add Access Point to add an access point configuration to the positioning settings.
    2. Specify Cartesian Position: X, Cartesian Position: Y, and Cartesian Position: Z values for your access point.
       These are the x, y, and z coordinates for the access point in millimeters.
    3. Specify any distance Offset to be used for the access point.
       The offset value is specified in millimeters.
       Offsets are used for precision tuning of the access point. Usually, this value is zero. However, if your access point reports a non-zero distance even when an android device requesting distance is at the access point, then this non-zero distance is used as the offset for the access point. The offset distance is automatically subtracted from reported distances.
    4. Under Access Point, select the existing access point name.
    5. Click Create to complete the access point configuration.
    Repeat the above steps to configure additional access points.
11. Click Save to save the positioning settings.

Repeat the preceding steps to create positioning settings for other locations.

Associate Positioning Settings with a Project

To use Wi-Fi based positioning in a project, you need to associate your positioning settings with the project.

1. Click Menu and then click Projects.
2. Select your project in the Projects list in the left pane.
3. Click Edit Project Details in the right pane.
4. Click the Project Positionings tab.
5. Under Project Positionings, select your project positioning name.
   If your project has multiple locations, and you have created more than one positioning settings, you can select all the positioning setting names that apply.
6. Click Save and close the window to return to the Projects page.