Positioning

Introduction

Once your anchors have coordinates, the positioning will start automatically. You can see this in the visualization page.

When clicking on the buttons showing the amount of working tags or anchors, you will see a list of those respective devices. Each ID is also clickable to provide more information about that particular device’s settings.

For tags, you can see the update rate, the current coordinates, the UWB settings… but also the firmware and hardware versions on the device. The selected tag will also be highlighted, and other tags will be shown less bright.

This works for anchors as well. When pressing the "Actions" foldout, you can also choose to forget the individual device, removing it from the list.

Positioning settings

Not every installation is the same, and sometimes you will want to tweak some of the positioning settings to get the best result. You can navigate to both positioning settings and UWB settings in the ‘Settings’ page of the Creator Controller.

The positioning settings offer options to configure the operation of the positioning algorithm. The default settings should suffice for a lot of setups, offering a good update rate and good positioning performance.

As you can see below, hovering over an option will show you detailed information about that options. Hovering over the different options gives detailed information about the option.

You can also configure a filter that will be applied to the positions. This way, you don’t need to do this in post-processing. In general, increasing the filter strength slider will make the positioning smoother, but will also increase the delay on the position.

The sensor data allows you to configure which extra tag sensor data should be present in the positioning stream.

An important new feature is ‘Off-board’ positioning. When positioning this way, the tag will calculate its ranges with the anchors but the final position will be calculated in the Creator Controller. This should both improve the update rate and positioning accuracy, especially in the z-direction. This is a new feature, and is not enabled by default to prevent regressions.

UWB settings

The UWB settings also have a large impact on the positioning and the update rates that can be achieved. However, playing with the UWB settings is considered more advanced for the simple reason that all devices in the system must be on the same UWB settings to work together.

Saving the settings will try to save the UWB settings on all tags and anchors within range that have been discovered and are in use. This is not always possible. The settings may result in a different radio range and consequently, some devices may be in range for one combination of UWB settings, but not for another.

For larger setups, it may be necessary to move around to update all devices and to verify their settings using discoveries.

If you have old or new devices on different UWB settings than you configured, or can’t find your devices in general, performing a ‘Full discovery’ is recommended.

For each setting the system again provides useful tooltips on its effect, but they’re listed in more detail here below.

• Channel: the UWB channel. The pozyx device can use 6 independent UWB channels. Devices on different UWB channels cannot communicate and do not interfere with each other. In general, lower frequencies (i.e. lower channel numbers) also result in an increased communication range. The antenna on the developer devices works has the longest range on channel 2.
  Data bitrate: the UWB bitrate. Three possible settings are possible: 110kbit/sec, 850kbit/sec and 6.81Mbit/sec. A higher bitrate will result is shorter messages and thus faster communication. However, this comes at the expense of a reduced operating range. The effect of the bitrate on the duration of ranging or positioning is shown in the figures below.

• Pulse repetition frequency (PRF): the UWB pulse repetition frequency. Two possible settings are possible: 16MHz or 64MHz. This settings has little effect on the communication rate. However, when you want two setups on the same UWB channel, changing this setting between the two will reduce interference.

• Preamble length: the UWB preamble length. This setting has 7 different options: 64, 128, 256, 512, 1024 or 2048 symbols. A shorter preamble length results in shorter messages and thus faster communication. However, this again comes at the expense of a reduced operating range.

• Tx gain: the UWB transmit power. The power can be set between 0 and 33 dB, and each channel has a default value. The maximum transmit power you can legally configure your devices with depends on your country.

Now that your tags are positioning, you can easily integrate the Pozyx position data in your own applications using our MQTT streams. The next section explains how to do this for both a local and a cloud-based stream.