The UWB settings have a large impact on the positioning and the update rates that can be achieved. Four UWB profiles have been predefined: A high speed and low speed profile for channel 5, and a high speed and low speed profile for channel 2:
- High speed: The default UWB profile and best suited for short range positioning with high update speeds and/or many tags. This profile uses shorter UWB packets corresponding to a higher bit rate of 6.81 Mbps and a short UWB preamble length equal to 64 symbols. A high bitrate and short preamble length will result in faster communication, however at the expense of a reduced operating range. The Pulse Repetition Frequency is equal to 64 MHz.
- Low speed: Configured for longer ranges and more accurate positions. Longer UWB packets are used corresponding to a lower bit rate of 110 kbps. The preamble length is longer and equal to 1024 symbols. This will result in a high operating range, at the expense of lower update rates and/or lower number of tags. The Pulse Repetition Frequency is equal to 64 MHz.
A correct configuration for your system is a trade-off between speed of the updates or number of tags concurrently positioning and positioning range. The Pozyx system also supports values in between high and low speed, but these two predefined profiles are sufficient for 99% of all applications. In TWR mode, only the high speed profiles are currently supported.
The Pozyx system can use 6 independent UWB channels1. Devices on different UWB channels cannot communicate and do not interfere with each other. A general rule is that lower frequencies also result in increased communication range. The longest range is achievable on UWB channel 2, but channel 5 is accepted without restrictions in most parts of the world. If other settings are required for you setup, please contact our support team at firstname.lastname@example.org.
|Channel||Center frequency (MHz)||Band (MHz)||Bandwidth (MHz)||Remarks|
|1||3494.4||3244.8 – 3744||499.2|
|2||3993.6||3774 – 4243.2||499.2||Preferred channel for long-range|
|3||4492.8||4243.2 – 4742.4||499.2|
|4||3993.6||3328 – 4659.2||1331.2|
|5||6489.6||6240 – 6739.2||499.2||Accepted without restrictions in most parts of the world|
|6||6988.8||6739.2 – 7238.4||499.2||Not supported at the moment|
|7||6489.6||5980.3 – 6998.9||1081.6|
Power should be selected high enough so that the anchors have good UWB ranging with their neighbors. On the other hand, it is not always beneficial to use the highest available power, as higher power may also result in more reflections of the UWB signal. In an optimal configuration, minimal power is assigned that results in good ranging between neighboring anchors.
After changing the UWB settings in the web application, your tags should be updated as well. If changes are made to the UWB settings without reconfiguring the tags, the tags will disappear from the visualization and MQTT stream. See the Tags setup section for instructions on how to do this.
1 But only channel 2 and 5 are supported out of the box at the moment.