Spaces Heatmap, footfall, and Polygon Zones analytics rely on the capability of the Wi-Fi network to estimate the position of each device on the floor plan. Access Points can track the location of client devices based on the signal strength of the signals they emit. This helps to locate client devices that are either stationary or moving inside the intended area.
Currently, positioning data is provided only by a limited number of vendors, as detailed in this article. But, having the Wi-Fi network with positioning technology is not sufficient to get started with these solutions, there are minimum design standards that have to be filled.
If you are installing a new network, we recommend putting time and effort into designing for Wi-Fi position tracking, because if the design does not meet the application needs it will be more difficult to compensate post installation.
Minimum number of sensing devices
Although mathematically positioning algorithm requires the device to be seen by at least 3 sensors, in a real world where the network layout is not optimal, is a good practice to have a minimum of 4 Access Points seeing a specific device at the same time.
To give the most accurate results, the placement of the Access Points must be laid out in accordance with the following guidelines:
- At least 4 sensors cover each point on tracking area
- Perimeter of sensors around the tracking area
- Do not place sensors in a straight line
Below are a couple of examples of bad and good layouts. The following design is a bad layout, the density of APs is too low, the sensors are not installed along the perimeter.
the following design is a good layout. There are 4 or more sensors covering each point on the tracking area and spread throughout the environment. There is also a perimeter created that contains multiple sensors.
A general step by step method is to place sensors around the perimeter. Once the perimeter is configured, place sensors in the center. Finally, fill in the gaps between the perimeter and center to complete coverage
Minimum Polygon Zone size
WiFi positioning technology estimates the position of the clients on the tracking area by means of triangulation techniques. The precision of the positioning varies based on different factors, including the density of sensors and layout. In average, most of the Wi-Fi vendors, estimate their technology to provide a precision of 10-12 meters.
Considering the average precision of the positioning algorithm, it is a best practice to define Polygon Zones that are much larger than the average positioning error.